For astronomers, the moon is both a blessing and a nuisance.  It鈥檚 considered a nuisance when its bright glare drowns out the dim light from faint and fuzzy deep sky objects that we all want to either observe or photograph.  But at the same time it is also a blessing in that we have such a remarkable world right in our very own backyard.  The moon offers so much astonishing beauty and detailed features that stargazers of any level of experience will always be richly rewarded by spending a little time with it.   And of course, the more you learn about the moon the more fascinating an object it becomes.

In this episode I have randomly chosen five different things that I personally find amazing about the moon and that perhaps you might not have heard of.  So, here they are, and listed with no particular order in mind.

Number one,  THE MOON HAS BOTH AN ATMOSPHERE AND WATER

Okay, I鈥檝e cheated a bit and worked in two amazing things under one heading. 

Until recently, the conventional thinking was that the moon was both airless and completely dry but new findings tell us a rather different story.  

Granted, there isn鈥檛 much of an atmosphere.  To give you some perspective, at sea level here on Earth our atmosphere contains about 100 billion billion molecules per cubic centimeter.  On the moon, you would only find about 100 molecules per cubic centimeter, just enough to distinguish it from the hard vacuum of space.  But keep in mind that even 100 molecules per cubic centimeter is about what you鈥檇 find in some of the best lab created vacuums here on Earth.

The exact composition of the lunar atmosphere is still unknown but to date we have identified sodium and potassium as well as argon, helium, oxygen, methane, nitrogen, carbon monoxide, carbon dioxide, and radon.

The origins for this very tenuous atmosphere is also a mystery but lunar scientists suspect that there are several different sources.  Outgassing, the release of gases from inside the moon, is one possibility.  The solar wind and high energy particles colliding with the lunar surface and chipping off atoms may be another.  Material being released from the impacts of micrometeorites may be yet another source.

NASA scientists have a special name for this kind of very thin atmosphere, they call it an 鈥渆xosphere鈥�, and it is probably the most common type of atmosphere on various kinds of small bodies throughout our solar system.

The evidence for water on the moon comes from a number of sources, including impact probes, orbiting spacecraft, and from moon rocks collected by the Apollo astronauts.

Upon initial analysis of those rocks the verdict was that the moon was bone dry but some 40 years after that assessment, orbiting spacecraft have detected the signature for water at the moon鈥檚 poles.

Of course liquid water cannot exist on the moon but it may occur as ice within the permanently shadowed craters located at the poles.  Elsewhere on the moon water occurs as the molecule hydroxyl (which is one oxygen atom and one hydrogen atom).  Some of this water is found within the lunar soil and a re-analysis of those moon rocks have shown that it is also trapped within tiny crystals of a mineral known as 鈥渁patite鈥�.E
How much water there is on the moon is still a matter of debate.  Some scientists say that there is as much as 64 parts per billion, two orders of magnitude greater than previously thought.  This still means that the moon is drier than any desert on Earth.

Some of the moon鈥檚 water may have been delivered by asteroid and comet impacts but the most important source may be due to the influence of the Sun.  The solar wind that I mentioned earlier is a constant stream of particles being emitted by the Sun.  Some of these particles are hydrogen protons.  When these hydrogen protons collide with the oxygen rich materials at the surface they may cause free oxygen to be released and if a hydrogen proton collides with an oxygen atom with enough force they may stick together to form water鈥檚 close cousin, hydroxyl.

Number two, MOONQ糖心Vlog传媒KES

A moonquake is the lunar equivalent of the earthquakes that we experience here on Earth.  During the Apollo missions from the years 1969 and 1972, astronauts placed seismometers on the moon which sent data back to Earth up until 1977 when they were switched off.  They revealed to us that there are four types of moonquake.

1    Deep moonquakes that originate over 400 miles within the lunar interior
2    Quakes triggered by the impact of meteorites
3    Thermal quakes triggered by the expansion of the frozen crust upon being exposed to sunlight after having been in the deep freeze for two weeks of lunar night and
4    Shallow quakes that occur about a dozen miles or more beneath the surface

The first three kinds of quake are fairly minor but the shallow quakes were the strongest, some of which reached magnitude 5.5 on the Richter scale.  Here on Earth that is enough to move heavy furniture around and crack plaster.  What鈥檚 even more interesting is their duration.  On Earth strong quakes may last only a couple of minutes but on the moon these shallow quakes can go on for at least 10 minutes with the moon ringing like a bell.  Why the difference?  Well, here on Earth rocks can become saturated with water and the energy from an earthquake deadens as it tries to propagate through it.  The moon, lacking as much water as does the Earth, has rocks that are far more rigid and quakes can keep them vibrating like a tuning fork for much longer periods of time.  If we ever set up colonies on the moon we had better have quake-proof housing.  As to why the moon experiences quakes it is still something of a mystery.  Some of them may be triggered by tidal interactions with the Earth while others may be caused by the rims of young craters slumping in upon themselves.

Number three, if you were STANDING ON THE MOON, YOU WOULD SEE THE EARTH GO THROUGH PHASES

The moon does not generate any light of its own, all of its light is reflected sunlight.   We see the moon go through a set of phases (new moon to full moon and then back to new) every 29.5 days.  The reason we see these phases is because the moon and the Earth orbit around one another and we see various portions of the lunar surface illuminated as the angle between the Sun, moon, and Earth constantly changes. 

But did you know that, from the moon鈥檚 perspective, the planet Earth would also be seen going through a full set of phases?   However, the Earth鈥檚 phases would be the opposite of the phase that we are seeing for the moon.  For example, during a waxing gibbous moon phase (which is when the moon is close to being full) any astronaut on the lunar surface would see a slender crescent Earth.  A few nights later, when the moon becomes completely full here on Earth, our lunar astronaut wouldn鈥檛 see the Earth at all.  At this time the moon, Earth, and Sun are all aligned with the Earth in the middle.  From the moon the Earth would appear to be lost in the Sun鈥檚 glare.

From here on Earth we see the moon rise and set because our planet revolves upon its axis once every 24 hours.  But the moon has a 1:1 spin-orbit resonance.  In other words, it rotates once upon its axis for every time that it takes to orbit around the Earth and the upshot of this is that the moon always presents one face towards us.  So, while we see the moon rise and set, from the moon the Earth would always appear to be in one place in the sky, spinning around every 24 hours to show off it various features, and slowly going through its phases just like the moon does.

Number four, NO ONE CAN OWN THE MOON

Just because American astronauts have planted flags upon the moon does not mean that the United States owns the moon.  Neil Armstrong and Buzz Aldrin planted a flag on the moon purely as a ceremonial gesture and nothing more.  On January 27th, 1967 the United Nations adopted the Outer Space Treaty which states that free access is granted to all celestial bodies and that 鈥渙uter space is not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means.鈥�  By the same token, the treaty also states that weapons of mass destruction and all military activity is strictly prohibited in space.

That still hasn鈥檛 stopped certain enterprising individuals form laying claim to ownership of the moon and some of them will even be glad to sell you some very nice lunar real estate.    They claim a loophole in the U.N. treaty but Article VI of the Outer Space Treaty clearly states that non-government entities are just as bound to its provisions as are all member nations.

So, if you鈥檝e paid good money for lunar property be aware that it is only worth the paper it is printed on.

And number five, THE MOON IS LEAVING US

Yes, it is indeed true that the moon is moving farther away from the Earth.  Here鈥檚 why鈥�

The answer has to do with tides and the gravitational embrace that is shared between the Earth and the moon.  The side of the Earth that faces the moon feels a greater gravitational pull than does the center of the Earth, and the side that is facing away from the moon feels an even weaker pull.   The net effect of this is that the moon鈥檚 gravitational tug creates two tidal bulges in our Earth鈥檚 oceans (one on the side facing the moon and one on the side facing away).

But these tidal bulges are not static, the Earth is rotating underneath them.  Now, keep in mind that these tidal bulges have mass and as a consequence they also exert a gravitational pull on the moon.  So, as the Earth spins faster than the moon can orbit around us, these tidal bulges try and drag the moon ahead in its orbit.  But the moon is having none of it, it pulls back and slows the Earth down in its rotation.

This pulling back and forth between the Earth and moon, combined with the tidal friction that it generates, takes energy out of the Earth鈥檚 rotation.   In fact, the Earth鈥檚 rotation is slowing down by about 2 milliseconds every century.   Sure, not so much that you and I notice in our day to day lives but it is a measurable effect and one that the U.S. Naval Observatory has to factor in every now and again to keep our atomic clocks in check.  But this energy taken out of the Earth鈥檚 rotation has to go somewhere, it doesn鈥檛 just disappear, so it ends up going into increasing the size of the moon鈥檚 orbit.  The end result of this is that the moon is moving away from the Earth at the rate of about 1.5 inches per year.  We can actually measure this by bouncing lasers off of specialized reflectors the Apollo astronauts left on the moon鈥檚 surface.  But don鈥檛 worry, it will take a very long time before anyone notices and before we do the Sun will have likely swelled into a red giant star, engulfing the Earth and moon and turning us into a charred cinder.  So yeah, there鈥檚 that.

Before we go I want to recommend two books about a group of extraordinary women whose mathematical abilities paved the way for the human race鈥檚 journeys into space.  But, because of their gender (and in some cases, their race) history has ignored their contributions up until now.

The first book is 鈥淩ise of the Rocket Girls: The Women Who Propelled Us, From Missiles to the Moon to Mars鈥� by Nathalia Holt.

The second book is, 鈥淗idden Figures: The American Dream and the Untold Story of the Black Women Mathematicians Who Helped Win the Space Race鈥� by Margot Lee Shetterly

Check your local library or bookstore for these two great reads.

That鈥檚 all for now.  Be sure and watch our web site for all the latest happenings in astronomy and be sure to take just a little bit of time to step outside and look up in both awe and wonder.

The post Five Things About The Moon appeared first on University Television - Comcast 61/1095 & UVerse 99.

Hello everyone, I鈥檓 Darrell Heath with the 糖心Vlog传媒LR College of Arts, Letters, and Sciences;
welcome to The Night Sky.
Stars are usually born in groups inside dense, vast, and cold clouds of molecular
hydrogen and dust. After they become full颅fledged stars they will disperse from their
parent clouds over a period of several million years.
Looking up at a star颅filled sky you can see groups of stars in various stages of this
dispersal process. At around 9PM during the month of March face towards the southwest
and locate the constellation of Orion the Hunter. Then locate the three bright stars that
form his belt and the fainter group of stars that hang off the side towards the east. These
fainter stars form the Hunter鈥檚 sword. Here you can see with your unaided eye a misty-
looking star. Take a good look at it with binoculars or a telescope and you are personally
witnessing one of nature鈥檚 Holy of Holies: stars in the process of creation, for this is the
Orion Nebula, one of the finest of our deep sky objects. Inside the nebula are hundreds
of stars in the process of being born; with a pair of binoculars you can see two of them
emerging from out of the gas and dust, with a telescope you can make out four of these
infant stars forming a grouping known as the 鈥淭rapezium鈥�.
The process of star birth is happening right this moment within the Orion Nebula but
shifting our gaze immediately west of Orion we find the constellation of Taurus the Bull
and within it are two star clusters of different ages and different stages of dispersal.
The Pleiades star cluster (also known as Messier 45) is an open star cluster that, at first
glance, seems to be made up of about six or seven faint stars. But binoculars reveal
many more and we know that there are actually as many as 400 stars all loosely bound to
one another by gravity. Over the next few million years the speed of any given star within
this cluster is sufficient enough to allow the star to escape the combined gravity of its
siblings and will eventually strike out on its own across the universe as a fully adult star.
Looking at the face of Taurus the Bull we see a V颅shaped pattern made up of about 20 or
so faint stars, this is the Hyades cluster. And, just as with the Pleiades, there are actually
several hundred stars forming the cluster. While the Pleiades is estimated to be a
youthful 100 million years old, the Hyades cluster is thought to be close to 700 million
years old. That鈥檚 certainly old by human standards but just stop to think that our own Sun
is a middle颅-aged star at about 4.5 billion years of age.
One of the first things you鈥檒l notice about the Hyades is how much further along the cluster
is in regards to their dispersal compared to the younger Pleiades. While the Hyades and
Pleiades share a close proximity together upon the sky they are not related to each other
but some astronomers believe that the Hyades do share a physical relationship with
another beautiful open star cluster, which is prominent in our late winter and spring skies.
To find it we must locate the constellation of Cancer, the Crab. Being one of the zodiacal
constellations you might think that Cancer is going to be a very bright and conspicuous
star pattern, it isn鈥檛. However, with the aid of a few other bright stars you should be able
to locate it fairly easily. My suggestion is to use a star chart or a stargazing app and step
outside at around 9 PM on a moonless night, in an area with only minimal light pollution,
and face the east. Look for the backward question mark pattern of stars forming the
mane of Leo the Lion. The bottom of the question mark is the Heart of the Lion, the bright
star Regulus. Throughout March you can use the planet Jupiter as a bright and handy
signpost to direct you towards Regulus. Now, using your star map or stargazing app
locate the nearby twin stars Pollux and Castor in the constellation of Gemini the twins. If
you draw an imaginary line from Regulus towards these twin stars, then about half way in
between them you should be in the Heart of the Crab and it is here that you will find the
wonderful star cluster known as The Beehive, or Messier 44.
The Beehive is one of those deep sky objects that鈥檚 best appreciated with binoculars
rather than a telescope. Why? Well, because it occupies an area upon the sky some one
and a half degrees across, or, roughly, the width of the three full moons placed side by
side. Viewing through binoculars will provide you with a much wider field of view with
which to encompass this impressive star cluster. A telescope will only provide you with a
very small field of view and you will miss out on all of M44鈥檚 grandeur.
But don鈥檛 think that the Beehive is bright and showy, it isn鈥檛 and you鈥檒l need a moderately
dark sky in order to see it naked eye. With the binoculars though you will be able to see a
swarm of about 30 bright and glittery stars but bear in mind that the cluster has over a
thousand all told.
Because the Beehive is about the same age as the Hyades (say, some 500 to 700 million
years) and because the stars in each cluster are chemically very similar, it is thought that
the two share a common origin but broke off into separate groups millions of years ago.
Another line of evidence that supports this theory is that the stars from both clusters all
appear to be traveling in the same general direction.
Aside being known as the Beehive or Messier 44 this cluster has had a variety of
interesting names across time and different cultures. To the ancient Greeks it was often
referred to simply as 鈥渢he small cloud鈥�. While to others it was known by the Latin name of
鈥淧raesepe鈥�, the manger. The story goes that the manger housed the two donkeys
belonging to the gods Dionysus and Silenus. In fact, the names of the two stars found on
either side of Praesepe are: Assellus Borealis (the Northern Donkey) and Assellus
Australis (the southern donkey). To the ancient Chinese the cluster was known by the
rather gruesome name of 鈥淓xhalation of Piled颅up Corpses.鈥�
But I will leave you with one other little tidbit about this cluster that has come down to us
from history. According to Pliny, the Greek naturalist and philosopher: 鈥淚f Praesaepe is
not visible in a clear sky it is a presage of a violent storm.鈥� There may in fact be
something to this bit of ancient weather lore. While a sky may look clear to our eyes
there can sometimes be high, thin cirrus clouds containing lots of ice crystals in our
atmosphere. These may be invisible to you and me but there are just enough of them to
make a normally dim patch of stars disappear from view in an otherwise clear sky. We
know today that the presence of such clouds are a good indicator that unsettled weather
is indeed close at hand.
Be sure to visit our web site for news and announcements as well as a list of various
astronomy resources available to you.
Until next time, I encourage you to get outside and look up in both awe and wonder.

The post The Celestial Swarm appeared first on University Television - Comcast 61/1095 & UVerse 99.

September of 2015 will go down as one of the best months of the year for Moon lovers of all kinds.  Not only do we have International Observe the Moon Night going on, but we also have a total lunar eclipse of the full Harvest Supermoon.

International Observe the Moon Night is an educational outreach event sponsored by various NASA and astronomical organizations and occurs on September 19th. It鈥檚 an educational outreach event sponsored by various NASA and astronomical organizations in order to get people outside and looking up at our nearest celestial neighbor. On this night astronomy clubs, planetariums, museums, and science centers all around the world will have telescopes set up for anyone curious enough to come out and see the Moon close up.

The moon鈥檚 phase for this evening is a 5-day-old waxing crescent. You may be wondering why we aren鈥檛 looking during a full Moon phase.  Well, a full Moon is actually the worst time to view the Moon with a telescope.  During a full Moon the entire surface is illuminated and the Sun鈥檚 light makes everything look flat and one-dimensional.  The best time to see the Moon through a telescope is when it is partially lit and the best place to look is along the terminator.  No, not the Arnold Schwarzenegger variety but the line that divides the Moon into its day and night sides.   If you were standing on the Moon along the terminator you would see the Sun rising or setting off to one side and its light would make the craters and mountains stand out in sharp relief.  Viewing from the Earth you would also benefit from this effect and from night to night as the terminator moves you get to see more and more varied terrain features.  On International Observe the Moon Night we will be able to see a number of the Moon鈥檚 maria, which are large, flat plains of solidified basaltic lava and they can be viewed in binoculars or even with the unaided eye.

There are other interesting lunar landforms that are favorable for viewing on the evening of the 19th   as well.    The Moon鈥檚 Caucasus Mountains, a mountain range some 520 km long and 6 km high will be viewable, as will the Valentine Dome, a low-profile volcanic dome just east of the south tip of the Caucasus鈥� and visible only when the terminator is near, like tonight.    Seeing the Moon鈥檚 ancient and battered landscape through a telescope is always a thrilling sight. If you鈥檝e never had the pleasure then you owe it to yourself to come out and take in the view.

The Central Arkansas Astronomical Society will be partnering with the Innovation Hub in North Little Rock on September 19th to celebrate the Moon. Telescope views, some of 糖心Vlog传媒LR鈥檚 finest meteorite specimens, science demonstrations, music, food, and more will be on hand at the Innovation Hub from 7-10pm. For more information about the event, visit the Night Sky website.
Moving on towards the end of the month we have a total eclipse of the full Harvest Supermoon on the night of September 27th.   Maybe we should take that apart and look at each component in a bit more detail.

A full Moon is when the Moon appears fully illuminated from our perspective here on Earth.  As the Moon and Earth orbit around one another we will only see a full Moon when the Moon is on the opposite side of the Earth from the Sun.

Harvest Moons are full Moons that occur either two weeks before or two weeks after the Autumnal Equinox, the first day of Fall in the northern hemisphere.  Now, the interesting thing about Harvest Moons is that they rise about 30 to 35 minutes later than they did the evening before which, traditionally, has served to provide farmers with extra light to work by in order to bring in their crops.

Normally there鈥檚 a difference of about 50 minutes in between rise times for the Moon each night, so what makes the Harvest Moon so different?

Well, it鈥檚 at this time of year that we see a change between the angle of the ecliptic with that of our horizon.   The ecliptic is the narrow path we see across the sky through which the Sun, Moon, and planets all appear to move over the course of the year.  What we call the ecliptic is in fact a reflection of our Earth鈥檚 orbital motion around the Sun.   Think of it as viewing our solar system鈥檚 plane edge on.  When you combine the fact that we are moving around the Sun with the fact that our axis of rotation is tilted by 25 and-a-half degrees you see something very interesting: the ecliptic is never in the exact same place throughout the entire year and changes with the seasons.  Around the time of the Autumnal Equinox each September we see that the ecliptic has a very narrow angle relative to the horizon.  Just compare September鈥檚 ecliptic with that of March鈥檚. In March the angle is very steep indeed, with a decrease in that angle we see a corresponding decrease in the times between successive moonrises and we get the phenomena we call the Harvest Moon.

The ecliptic gets its name from the fact that eclipses only occur along this path in the sky.  Now, the Moon orbits around the Earth once a month so, all things being equal, you might expect to see an eclipse once a month as well.  BUT, not all things are equal.  The Moon鈥檚 orbital path around the Earth is tilted by about 5 degrees with respect to the plane of the ecliptic.  This means that eclipses are infrequent and can only happen when the alignments between the Earth, Moon, and the Sun are very precise.  On the night of September 27th those conditions will be met and we will see a total lunar eclipse when Earth鈥檚 shadow completely covers the Moon鈥檚 disc.  Lunar eclipses can only occur during a full Moon and this particular one happens to be on the night of a Harvest Moon as well.

Provided the weather cooperates you can look at the start of the eclipse around 8:07PM with eclipse maximum occurring at 9:47PM.  This early evening event means that it will be a great time to be outside with family and friends to observe this amazing celestial spectacle.  You can see the event from anywhere that you have a clear view to the southeastern part of the sky.  Check out the Night Sky website for more info regarding viewing locations.

Last but not least, this particular eclipse of the full Harvest Moon will also be what is known as a 鈥渟upermoon鈥�.   Who says it鈥檚 a supermoon?  Astrologers and the news media do and, so, astronomers (people who are interested in the scientific aspects of our universe) simply ignore the hype.  According to astrologers, a supermoon is a full Moon that coincides with the Moon鈥檚 perigee: its closest point to Earth for the entire month.  The Moon doesn鈥檛 orbit the Earth in a perfect circle; if it did then its position would always stay the same.  Instead, the Moon鈥檚 orbital shape around the Earth is that of an ellipse, a somewhat flattened circle and its distance from us changes from day to day.  You might think that a full moon that is closest to the Earth will be noticeably bigger than any other full moon; sadly this just isn鈥檛 the case.   On this night the Moon is 221,754 miles away, closer than the average 239,000 miles distance, and, technically should be a bit bigger than most other full Moons but it鈥檚 just not significant enough for our eyes to even register the difference.  Oh, and don鈥檛 worry, a 鈥渟upermoon鈥� is not going to cause earthquakes or knock your chakra out of alignment.

So, even though you may not be able to discern any difference in the apparent size of the Moon you can still experience the optical illusion known as 鈥渢he Moon Illusion鈥� on any night of or around a full Moon.  For whatever reason our eyes and brain fool us into thinking that a Moon seen near the horizon is bigger than at any other time.  But it is in fact just a trick of the mind, a giant-looking Moon seen near the horizon is no bigger than any other time you鈥檝e seen the Moon.  You can prove this to yourself by holding an average-sized aspirin between your thumb and forefinger out at arms length.  Let it cover the rising Moon and then check back an hour or two later to repeat the experiment again when the Moon is higher up in the sky.  You will see that both Moons are in fact the same in angular size and that nothing has changed.

No matter when you observe the Moon, if you do it carefully and really take the time to notice details about it you can鈥檛 help but look up in both awe and wonder.

The post Celebration of the Moon – transcript appeared first on University Television - Comcast 61/1095 & UVerse 99.

Hi everyone, I鈥檓 Darrell Heath with the 糖心Vlog传媒LR College of Arts, Letters, and Sciences: welcome to The Night Sky.

On any given day of the year it鈥檚 estimated that the Earth collides with about 19,000 meteors weighing over 3.5 ounces.  The majority of these burn up in our atmosphere but a few do make it to the ground but fewer than 10 of these are ever recovered each year.   On the other hand, some 100 tons of dust-sized micrometeoroids rain down on our planet each day.   We occasionally see these bits of cosmic debris burning up in our atmosphere as a sudden streak of light in our night sky.  We often call them 鈥渟hooting stars鈥� but of course they aren鈥檛 really stars at all.  Most of this stuff is the random fragments that were left over from the birth of our solar system, but throughout the year there are certain nights when, rather than just seeing a few sporadic meteors every few hours, we can see anywhere from dozens to around a 100 meteor streaks per hour.  We call these events 鈥渕eteor showers鈥� and their source material often comes from comets.

One of the very best of our annual meteor showers occurs this month: the Perseids, so named because when you trace back all the meteors you see on the peak night they appear to originate from a point in the sky where we find the constellation of Perseus.  The source for the Perseid meteors is comet 109P Swift-Tuttle, which completes one orbit around the Sun every 133 years.   Comets are relatively small bodies left over from the formation of the solar system and are composed of various kinds of frozen gases along with bits of rock and dust.   Whenever Swift-Tuttle makes a close approach to the Sun, as it last did back in 1992, it begins to defrost and sheds large amounts of gas and dust in its wake.   These streams of comet material will follow along in the same orbital path as the object that produced them and eventually spreads out over time.  Like clockwork the Earth will plow through it every year and we get treated to a celestial light show when this comet dust burns up in our atmosphere some 60 miles overhead.   Now, Swift-Tuttle is big, its nucleus is 16 miles across: more than twice as big as the object thought to have wiped out the dinosaurs 66 million years ago; but the stuff you see creating those meteor trails are no bigger than a grain of sand.   How can something so tiny create something so bright and dramatic?   Well, meteoroids (which is what we call the bits of interplanetary material that creates a meteor streak) are travelling really fast: a piece of Comet Swift-Tuttle may be screaming into our upper atmosphere at a velocity of around 133,200 mph (many times faster than a rifle bullet).   The meteoroid has a lot of kinetic energy (the energy of its motion) associated with it and once it meets the resistance of our atmosphere (and suddenly slows down) that kinetic energy gets converted to thermal energy.  A fast moving meteoroid violently compresses a column of air out ahead of it as it slams into our atmosphere, this sudden shock to the air molecules makes them heat up and glow.  What we see as the sudden appearance of a meteor streaking across the sky is actually that superheated and glowing column of air being violently squeezed out ahead of the meteoroid.

So, when and where should you be outside and looking up for Perseid meteors?  The Perseid meteor stream is very wide and you can start seeing meteors from July 17th up to August 24th.  This year the peak time is the night of August 12th and into the morning hours of the 13th.  But, if the weather proves to be uncooperative then viewing will be just dandy during the morning hours from August 11th through the 14th.  The best time to be on the lookout for the highest hourly rates (which on the peak nights can be anywhere from 50 to 100 meteors per hour) are from midnight until dawn.   The reason for this is that it鈥檚 during these hours that the side of the Earth we are on is facing in the same direction that our planet is orbiting around the Sun.  It鈥檚 a bit like being in a car and looking out through the windshield into an oncoming snowstorm.  Earlier in the evening the meteors will have to catch up with the Earth to collide with our atmosphere but in the wee hours of the morning we are driving head on into the meteor stream.  But, don鈥檛 rule out looking during the early to late evening hours.   At this time the shower鈥檚 radiant (the constellation Perseus and the spot from which the meteors all appear to radiate from) is low in the sky and if you鈥檙e lucky you might see an 鈥渆arthgrazer鈥� meteor.  These are bright and very slow moving meteors traveling in a horizontal, overhead path.

The best way to see any meteor shower is to go the best dark sky site you can find, this often means getting away from your neighborhood or city in order to escape light pollution.

Get comfortable.  Lie out on a blanket or a reclining lawn chair and simply look up.  While the constellation of Perseus is the radiant point and is in the northeast part of the sky you will still see meteors in all directions, so don鈥檛 focus on just one area of sky.

Expect lulls in meteor activity punctuated by sudden outbursts.

Keep insect repellant on hand as well as lots of water to stay hydrated.  Snacks won鈥檛 go amiss either.

Invite family and friends. A meteor shower party is a great bonding experience and even if you don鈥檛 see many meteors, you鈥檒l at least have spent some quality time with people you care about and maybe even have created a few memories that will last you and them a lifetime.

All you really need are your eyes to see meteors but you might consider a pair of binoculars as part of your equipment.  Use them to scan the rich star fields of the Milky Way, which is arching high overhead by midnight.  Pay close attention to the constellations of Sagittarius and Scorpius low upon the horizon in the southwest at midnight.  These star patterns are especially rich in star clusters and nebulae, many of which are easily seen with binoculars.    Use a star map found in the latest issue of an astronomy magazine, an app, or download one for free from skymaps.com in order to find constellations and the deep-sky treasures hidden within them.

Also, be sure to watch the Central Arkansas Astronomical Society鈥檚 web site for announcements of meteor shower observing nights at their River Ridge Observatory.

Most of all just get outside and look up because I guarantee that once you start seeing meteors you鈥檒l be looking up in both awe and wonder.

The post The Night Sky – Perseid Meteor Shower Transcript appeared first on University Television - Comcast 61/1095 & UVerse 99.

Hello everyone, I鈥檓 Darrell Heath with the 糖心Vlog传媒LR College of Arts, Letters, and Sciences; welcome to The Night Sky.

Remember when our solar system had nine planets?  Our little corner of the universe seemed so familiar and well organized back then: we had the Sun, four rocky inner planets, an asteroid belt, four outer gas giant planets, a number of moons, the occasional comet, and diminutive little Pluto hanging out all alone in the outskirts.  But in 2006 we lost Pluto as a member of the planet club.  What changed?  How can you demote a planet?  And who has the authority to even do such a thing?

Our story begins in1905 with the hunt for a theoretical Planet X thought to exist just beyond the orbit of Neptune.  Astronomers noted that there were some slight irregularities in Neptune鈥檚 orbit and they suspected that an undiscovered planet鈥檚 gravitational tug might be the culprit.  In 1929 the Lowell Observatory in Flagstaff, Arizona hired a 24 year old farm boy and self taught astronomer named Clyde Tombaugh to hunt down Planet X.

The work was tedious and involved Tombaugh taking two photographs on glass plates of the same section of sky several nights apart.  He would then put the plates on a machine that allowed him to flip the two images back and forth so quickly that they would appear as one.   Each plate contained thousands of stars and Tombaugh was looking for one tiny dot in a sea of dots to move ever so slightly between frames.   After a year of doing this day in and day out the tedium finally paid off and Tombaugh found what he was looking for.   The story made front-page headlines around the world and since the object appeared to be round and everyone expected to find a planet, a planet it was deemed to be.

A young schoolgirl in England read the story and thought that a world in such a far-flung corner of the solar system should be named for the Greek god of the underworld, Pluto.  Her grandfather even wrote a letter to the Lowell Observatory鈥檚 director to make the suggestion and the name stuck.  Later that year animator Walt Disney, who always had an interest in space and space exploration, debuted a loveable dog character with the same name in one of his cartoons.  If anything this helped to cement the popularity of planet Pluto with the public.

The technology available at the time couldn鈥檛 really tell us much about an object so small, faint, and distant as Pluto.   For many years the only thing we knew with any certainty is that Pluto orbited the Sun in a very odd manner.  All of the other planets move around the Sun in nearly circular orbits but not Pluto.  Its orbit is highly elliptical; what鈥檚 more is that during part of its 248 Earth-year long orbit around the Sun Pluto actually crosses over Neptune鈥檚 orbit.  This means that for 8% of Pluto鈥檚 orbit it鈥檚 closer to the Sun than is Neptune.  Odder still is that Pluto doesn鈥檛 orbit within the same plane as all the other planets, its orbit is tilted by 17 degrees relative to the solar system鈥檚 plane.  It鈥檚 almost as if Pluto were trying to behave differently from all the other planets!

Pluto remained both an oddity and a mystery well into the 20th century.

After Pluto鈥檚 initial discovery people began to puzzle over the fact that this remote little world appeared so all alone, it seemed to exist out of context with the rest of the solar system.    Many astronomers, Clyde Tombaugh included, began a search for any neighbors that Pluto might have.   Nothing turned up but, given what we knew about the solar system鈥檚 formation, astronomers were certain there must be a realm just beyond Pluto where the frozen relics that went into its making were sure to be found.  Most of these objects, the reasoning went, would be the source for our short period comets while others would most likely be small worlds akin to Pluto

Yet Pluto remained a lonely anomaly until 1978 when astronomers discovered that it had a moon.  This companion to Pluto was named Charon and the two are locked together in synchronous rotation.  By watching the two orbit around one another astronomers were able to work out their mass and size.  Pluto is some 1,433 miles in diameter while Charon is a little more than 750 miles across; both worlds could easily fit across the continental United States. Some astronomers prefer to think that the two are in fact a double planet system rather than a planet and moon.   Today there are a total of five known moons, all tightly packed together, and it鈥檚 thought that the system may be the debris left behind after something big collided with Pluto long ago.

Beginning in the 1990鈥檚 astronomers began to find even more objects within Pluto鈥檚 neighborhood; in fact, there are some 1,300 known icy objects in this outer zone of the solar system we now call the Kuiper Belt (in honor of astronomer Gerard Kuiper, one of the big proponents of its existence in the 1950鈥檚).  Some of these objects are icy boulders while others are nearly as big as Pluto and we suspect that there could be billions more out there.

All of these discoveries begged the question as to whether or not Pluto and other Kuiper Belt objects could rightfully be called planets or whether they should belong to a special category all their own.  Much to the embarrassment of the astronomical community came the realization that there wasn鈥檛 a formal definition of what a planet actually is.   The International Astronomical Union, the organization responsible for officially naming celestial objects, decided to rectify that.   The IAU came up with three criteria an object must meet to defined as a planet:

1)    The object must orbit the Sun.  No problem there, Pluto certainly does that.
2) The object must be massive enough to have pulled itself into a spherical shape.  Pluto meets this requirement too.

2)    The object must be able to have cleared the neighborhood of its orbit.  This
means that a planet must be the dominant gravitational presence in its orbit. Like all the other classical planets it must have consumed smaller bodies or hurled them out of its way.   Clearly, Pluto was not massive enough to have done that and, so, it was deemed not a planet.  Instead, it belongs to the new category known as a dwarf planet.   Rather than Pluto being the solar system鈥檚 ugly stepchild it had now found its rightful place as one of the largest members of its kind in a newly discovered realm of the solar system.   Unfortunately the public and many in the astronomical community didn鈥檛 see it this way.  There were organized protests and many an angry letter written to various scientists deemed as being 鈥淧luto Killers鈥�.

Perhaps in the end it doesn鈥檛 really matter what we call Pluto, the argument may be nothing more than a case of 鈥測ou say tomato and I say tomato鈥�.  What really matters is that Pluto is a world worth knowing and this month, after a nine and half year journey, NASA鈥檚 New Horizons spacecraft will make a flyby to image, map, study, and reconnoiter this distant world and its busy moon system.   Up until now all of our images of Pluto have been nothing more than fuzzy blobs of pixels but now we should be getting high definition images of this mysterious world.   After its flyby of Pluto the spacecraft will head deeper into the Kuiper Belt to explore.  New Horizons is literally sailing into unknown waters and who knows what wonders await us there.   Exploration and discovery is what makes the human adventure worth being a part of and I for one eagerly await what we will learn about Pluto and the other denizens of this remote corner of our solar system.

Also, in a fitting side note, New Horizons is carrying some of Clyde Tombaugh鈥檚 ashes out to the little world he discovered all those years ago in 1930.

Visit our web site to see postings of New Horizon鈥檚 discoveries as they become available.

Until next time I encourage you to take a little time to step outside and look up in both awe and wonder.

The post Pluto and the Planetary Blues – Transcript appeared first on University Television - Comcast 61/1095 & UVerse 99.

by Darrell Heath

Hi everyone, I鈥檓 Darrell Heath with the 糖心Vlog传媒LR College of Arts, Letters, and Sciences; welcome to The Night Sky.

As an amateur astronomer I鈥檓 always looking up. During the day it鈥檚 possible for me to see such things as rainbows, solar halos, strange cloud formations and even the Moon. At night I have the stars, planets, meteors and even the occasional comet to look out for. All of these things are naturally occurring objects and phenomena that any of us can observe throughout the year.   But ever since 1957 when Soviet Russia launched Sputnik, the first satellite to orbit the Earth, we鈥檝e had human made objects to look for in the night sky as well.

Some estimates place the number at over 30,000 man-made objects in orbit around the Earth right now. Over 1200 of those are operational satellites, the rest is 鈥渟pace junk鈥�: intact but out of control satellites, bits and pieces of broken up satellites, or the spent rocket bodies that carried them out into space.  Functional satellites include those used for communications, geophysical surveys, weather monitoring, navigation, spy and military operations, space telescopes, and even those large enough to hold a crew of several humans.

How high up a satellite is depends on such things as its purpose, how long it鈥檚 meant to stay in orbit, and whether or not maintenance or servicing is required.   The highest satellites are 22,223 miles above us. They travel around the globe near the equator in geosynchronous orbits: in other words their revolutions match that of the Earth鈥檚 and they鈥檙e always positioned over the same spot on the planet. Television and communication satellites use these orbital positions.   From geosynchronous orbits down to about 1,243 miles you鈥檒l find satellites traveling in Medium-Earth orbits, GPS satellites are often found here.   Satellites that are meant to survey and image the Earth, or are serviced periodically, travel in Low-Earth orbits, anywhere from 111 miles to 1,243 miles above. This is the home of spy and military satellites as well as weather monitoring satellites and the International Space Station.

On any given night of the year it鈥檚 possible for you to see a satellite passing overhead, but it鈥檚 usually those in Low-Earth orbit that are seen the most often.   No optical aid is needed, just use your eyes to scan the sky and look for a faint star-like object moving against the background stars.   Within about 15 minutes you should see at least one or two. If you see flashing lights of different colors then you鈥檝e spotted an aircraft and not a satellite.

As is the case with most things involving stargazing there鈥檚 an optimal time of night and year to observe satellites.   Keep in mind that satellites are not producing any light of their own, at least none that you can see. The light that makes them visible to our eyes is sunlight being reflected off their body or from panels. The best time to observe them is anywhere from 45 minutes to two hours after sunset or just before sunrise.   The sky has to be just dark enough to make them visible and yet not so late that your viewing location has passed within Earth鈥檚 shadow.   During the early evening, or just before sunrise, there鈥檚 enough sunlight hitting our atmosphere hundreds of miles above to light up a satellite or piece of space junk. The time of year can also be an important factor. During winter the Earth is in a point in its orbit so that Earth鈥檚 shadow is already well overhead soon after sunset, not a good time to see these otherwise faint objects. During summer our orbital position is now such that Earth鈥檚 shadow is angled southwards and never quite makes it overhead, even at midnight. Summer is prime time viewing season for satellites.

So, what can you expect to see?

Well, most satellites you see are going to be faint, just at the threshold of naked eye visibility.  Some may be as bright as the Moon or Venus! If your viewing location is optimal and you鈥檙e looking at the right time you can see anywhere from 10 to 20 satellites an hour.

While they don鈥檛 have blinking lights some of the out of control satellites and bits of space junk are tumbling in space. This can make them appear to flicker as they move across the sky.

Typically satellites will be traveling from a westerly direction towards an easterly direction and not the other way around. Satellites are launched this way to take advantage of Earth鈥檚 1,040 mph spin rate. Because the Earth spins faster near the equator most launches take place as near there as possible: you get to add more payload for less fuel this way.   Occasionally you鈥檒l see satellites heading on north-south trajectories, or vice versa; be sure to smile and wave when you see one of these because it may well be one of those spy satellites I mentioned earlier.

Satellites have no way of increasing or decreasing their speeds, they are falling to the Earth in a curve just fast enough to match the curvature of the Earth and to keep themselves in orbit. Usually you鈥檒l see them traverse the sky within a couple of minutes. If they鈥檙e traveling much faster then it鈥檚 most likely a dead satellite skimming the upper atmosphere and on its way towards a fiery death. Another spectacular display is when a Centaur, an upper rocket stage used to boost a satellite鈥檚 payload into space, vents some of its fuel, resulting in a glowing cloud of gas.

While the majority of satellite sightings are a bit on the dim side there are two that can occasionally shine as bright, or even brighter, than the planet Venus: the International Space Station and Iridium flare satellites.

At 450 tons and bigger than a football field the International Space Station is the largest man-made structure in space, it circles the globe in a Low-Earth orbit 225 miles up every 90 minutes.   The ISS is a microgravity laboratory and is occupied by six people at any one time; since its construction in November of 2000 over 200 people from 15 different nations have lived and worked there. Over an acre of solar panels extend out to either side of the crew and cargo areas and when the ISS passes over at just the right time and the sunlight hits those panels it can be the brightest object in the evening sky after the Moon.   Sometimes, when the ISS is angled just right towards the Sun the station can appear to flare in brightness to magnitude -8; more than 16 times as bright as Venus!

It鈥檚 orbit around the Earth is inclined by about 52 degrees with respect to the globe鈥檚 equator, this means that just about everyone on the planet gets to see it at one time or another, but you鈥檒l have to know exactly when in order to see it. The best way to do that is to have NASA send you email notifications as to the time, date, and viewing directions. Visit spotthestation.nasa.gov to sign up. Alternatively you can visit web sites such as Heavens-Above.com for a customizable itinerary.   There are even a number of apps that will notify you as to the next flyover. It鈥檚 best appearances are when it鈥檚 higher than 20 degrees above the horizon, anything below that means it will be difficult to see and rather dim to boot.

Iridium satellites are older spacecraft used for voice and data coverage to satellite phones and pagers and they orbit about 500 miles above the Earth.   They are also one of the most dramatic satellite performers you will see in the night sky. Each spacecraft is equipped with three door-sized and highly reflective antenna arrays and during a favorable flyover sunlight will hit them and direct it back to an observer on the ground.   This creates the spectacular sight of a dim-looking satellite suddenly flaring in brightness; so much so that at times it can become 25 times brighter than the planet Venus.   Many people who happen to see one often mistake it for a fireball or UFO. Check with the Heavens Above web site for flyover times and, yes, there are even apps for that as well.

While you are gazing up and looking for these moving dots of light in the dark here is something to think about.

The furthest a human being has traveled in space is when the crew of the ill-fated Apollo 13 mission used the Moon鈥檚 gravity to help slingshot them back safely to Earth. At the furthest they were 248,655 miles away: no human has ever been more distant. The furthest a man-made spacecraft has ever been is the Voyager 1 space probe, currently 11 billion miles away, within the edge of interstellar space. The closest star system to Earth is Alpha Centauri, some 4.3 light years away. Traveling at the speed of one of NASA鈥檚 retired space shuttles, say 17,600 mph, it would take you 165,000 years to reach Alpha Centauri (and that鈥檚 with no potty breaks!). While those satellites we see appear to be very distant the truth is that we have just barely dipped our toes into the great cosmic ocean.

Until next time I encourage you to get outside and look up in both awe and wonder.

The post Satellite Nights – Transcript appeared first on University Television - Comcast 61/1095 & UVerse 99.

Hi everyone, I鈥檓 Darrell Heath with the 糖心Vlog传媒LR College of Arts, Letters, and Sciences; welcome to The Night Sky.

Almost from the moment of its invention in 1608 the telescope revolutionized our understanding of the universe and how we fit within it.   Using a crudely made telescope of wood and leather Galileo managed to bring two thousand years of dogma and human ego crashing to the ground by showing that Earth moved around the Sun along with all the other planets and not the other way around. His telescope used glass lenses to collect light and could only magnify objects 20 times; Sir Isaac Newton perfected the telescope a few years later with his own design that used a curved metal mirror to collect light rather than glass lenses, which were prone to color distortion of the image. Newton鈥檚 design also allowed for telescopes to be made bigger and cheaply. 400 years on the telescope still remains the primary tool astronomers use to unravel the secrets of the cosmos.   In pursuit of that quest to understand how the universe works astronomers have developed ever bigger and better telescopes and with improvements in telescope technology there have also come major leaps in our knowledge.

For the first 30 years of the 20^th century the world鈥檚 largest telescope resided at the Mount Wilson Observatory in the San Gabriel Mountains just outside of Pasadena, California. It was a reflecting telescope similar to Newton鈥檚 basic design but rather than a metal mirror it used one made from two tons of melted and highly polished glass. Its aperture was 100 inches, a far cry from Galileo鈥檚 two-inch scope. And it was here at Mt. Wilson that not one, but two, revolutionary discoveries were about to be made.

In 1919 a young man named Edwin Hubble took a job at Mt. Wilson as an astronomer, in 1923 he became world famous by discovering that the Andromeda Nebula wasn鈥檛 just a cloud of gas within our own galaxy but, in fact, another island universe of stars like our own Milky Way, but much further away. In essence, Hubble discovered the universe; he demonstrated that galaxies existed outside our own and that they were distributed widely throughout the cosmos. Our universe became much bigger than we had ever thought possible.

His second discovery was even more astounding and Stephen Hawking has described it as 鈥�one of the great intellectual revolutions of the 20th century.”

Using Mt. Wilson鈥檚 100 inch telescope Hubble discovered that galaxies are moving away from one another, in effect: the universe was expanding. This revelation was to lead to what we now call the 鈥淏ig Bang鈥� theory. Later discoveries were to confirm this finding of an expanding universe and it is now an accepted fact of modern cosmology.

Now, astronomers enjoy a breathable atmosphere just like the rest of us but what they don鈥檛 like is how it distorts their telescope images as well as blocks out certain wavelengths of light. The universe advertises its presence across the entire range of the electromagnetic spectrum, everything from high energy Gamma rays to low energy radio and microwaves. The human eye can only see a very narrow sliver of the EM spectrum, wavelengths that are only 380 to 760 nanometers long, which is what we know as 鈥渧isible鈥� light. Our atmosphere does a very good job of blocking out a large part of the spectrum from ever reaching the surface of the Earth. This makes us blind to much of what the universe has to offer and by the middle of the 20^th century plans were being laid to place a telescope in space capable of seeing in various wavelengths, well above the blocking effects of our atmosphere.

In 1975 NASA teamed up with the European Space Agency to make what would become the Hubble Space Telescope a reality. By 1977 Congress had approved funding for the project and Hubble鈥檚 launch date was scheduled for October 1986. Unfortunately the tragedy of the Space Shuttle Challenger in January of that year resulted in a two-year delay for all NASA shuttle launches. Finally, on April 24^th, 1990, the Hubble Space Telescope was launched into space aboard the Space Shuttle Discovery. But there were more setbacks to come.

The first images from Hubble were blurry and for a piece of high tech equipment that cost over $2.5 billion dollars this was an unacceptable problem. The fault was due to Hubble鈥檚 94.5 inch curved mirror not being the correct shape as originally specified.   The flaw in the mirror was tiny; about 1/50th the thickness of a sheet of paper, but it was just enough to create the blurred images.   Engineers soon had a solution, a set of smaller mirrors would act as spectacles to correct the problem and would be installed as part of a space shuttle servicing mission. After a successful repair in December of 1993 the Hubble Space Telescope was back in business and ready to peer deep into the universe.

Hubble is specially equipped with a suite of five scientific instruments capable of looking at the universe in either ultraviolet, visible light, or infrared. Orbiting the Earth every 97 minutes the school bus-sized telescope is constantly gathering data in various wavelengths of light and sending it back to Earth. Astronomers routinely submit research proposals for various projects utilizing Hubble. Nearly 1,000 requests are sent in annually and around 200 are selected based upon which ones will make the best use of Hubble鈥檚 capabilities as well as whether or not the research being proposed has a high priority in astronomy.

Over the past 25 years the Hubble Space Telescope has made many astonishing discoveries about our universe but there are five in particular that stand out as being major scientific achievements.

#5 HUBBLE DEEP FIELD

One of the most important photographs ever taken is the Hubble Deep-Field, which allowed us to gaze across both space and time to when the universe was still in its infancy.   The first Hubble Deep-Field image was taken in 1995 when the telescope stared at a speck of seemingly empty space. The photo of this speck revealed some 3,000 individual galaxies going as far back in time as 10 billion years. It showed us that the earliest galaxies were small and irregular in shape and were probably the building blocks to the many large, grand spiral galaxies we see today.

#4 ALIEN ATMOSPHERES

While most extrasolar planets have been found using ground-based telescopes and various other space telescopes, Hubble has still made important contributions to their study. In 1994 Hubble showed that most of the infant stars within the Orion Nebula contain disks of gas and dust, the raw ingredients from which future planets will be made. In 2001 astronomers used Hubble to analyze the atmosphere of an alien world as it passed in front of its Sun-like star. This 鈥減roof of concept鈥� study shows that we can use the technique to look at other alien planets to see if their atmospheres might contain signature gases that would betray the existence of living organisms.

#3 SUPERMASSIVE BLACK HOLES

Astronomers had long suspected that the bright and busy cores of some galaxies were host to supermassive black holes, compact gravity monsters that are millions or even billions of times more massive than our own Sun.   Hubble not only demonstrated that these black holes exist but that they are a common component of many galaxies ranging from normal spirals to misshapen and distorted colliding galaxies. More importantly, Hubble has shown that supermassive black holes, in addition to being common, are also intimately connected to galaxy formation and evolution.

#2 DARK MATTER

The universe is filled with all kinds of exotic forms of matter and the most puzzling variety of all is one that we can鈥檛 even see: dark matter.   We鈥檝e suspected the existence of this weird form of matter since the 1930鈥檚 but it has only been in the past few decades that scientists have become more certain of its reality.   While we have no real clue as to the nature of dark matter we can see it鈥檚 gravitational effects on more familiar varieties of matter; namely in how it keeps fast rotating galaxies from flying apart and how it also keeps fast moving galaxy clusters all held together.

While dark matter doesn鈥檛 emit or absorb light its mass can distort the fabric of space-time around it and can bend the light coming from more distant background objects. The phenomena is known as gravitational lensing and astronomers using Hubble and other space telescopes have used it to map out the distribution of dark matter within the universe.   These maps show that the cosmos is not only made up of 85% of a substance that we don鈥檛 even understand but that is also filled with spider web-like strands of the stuff, which seems to act as a scaffolding upon which the universe鈥檚 largest structures are built.

#1 DARK ENERGY

Edwin Hubble discovered that the universe is expanding and for most of the 20^th century it was thought that all of the matter within it should be slowing the expansion rate down. But in 1998, two teams of scientists, working independently of each other, discovered that rather than slowing down, the universe鈥檚 expansion was accelerating.   Crucial to this research was the use of a specific kind of supernova event that astronomers often use as a cosmic yardstick when measuring distances across the universe. Only the Hubble Space Telescope could provide them with the level of precision needed to measure the most distant of these stellar explosions. We don鈥檛 yet know exactly what the energy source is for making the universe鈥檚 expansion rate accelerate and astronomers call it 鈥渄ark energy鈥� for that very reason.   Dark energy makes up 70% of the universe鈥檚 overall energy density and it may play a role in how the universe will meet its end. If the expansion rate continues or accelerates further then all of gravity鈥檚 work throughout the eons will come undone. Galaxy clusters will fall apart, the galaxies themselves will be torn asunder, and eventually even the molecules and atoms that make up visible matter will become shredded by the universe鈥檚 accelerated expansion.

Hubble has not only advanced our knowledge of the universe, it has also inspired works of art.   Choreographer Liz Lerman, recipient of a MacArthur 鈥済enius grant鈥�, created a contemporary dance piece called 鈥淭he Matter of Origins鈥� which included images taken with the telescope. Artist Tim Otto Roth has created two art installation pieces inspired by Hubble鈥檚 discoveries. There is even a Hubble Cantata written by composer and visionary Paola Prestini in collaboration with astrophysicist Mario Livio. The work incorporates orchestral arrangements, vocalists, multimedia, and narration. The work serves to intermingle the fate of one young woman with the ultimate fate of the stars and a full-length version of the cantata is expected to debut in time for Hubble鈥檚 25^th anniversary.

But it is those stunning images from Hubble with which most of us are familiar.   Even without understanding the science that underpins them we are struck by their incredible beauty and we marvel at the awesome grandeur of a universe so vast in scale that we can scarcely grasp its true immensity. Hubble has become our own personal avatar in an attempt to understand the universe and our place within it, it is, in a very real sense, an extension of our own eyes into space and through which we look up at the night sky in awe and wonder.

The post The Hubble Space Telescope: 25 Years on the Cosmic Frontier appeared first on University Television - Comcast 61/1095 & UVerse 99.

Hi everyone, I鈥檓 Darrell Heath with the 糖心Vlog传媒LR College of Arts, Letters, and Sciences; welcome to The Night Sky.

On a March evening in the year 1744 a 13-year-old boy living in Lorraine, France saw an amazing spectacle in the night sky that would inspire him to make astronomy his life鈥檚 work.  The boy鈥檚 name was Charles Messier and the spectacle was the Great Comet of 1744.  At the time that Messier observed the comet it had become so bright that it could be seen during the daytime and it displayed a stunning six tails that reached well above the horizon and fanned out in all directions.

This remarkable sight had a lasting impression upon the young Messier and he knew then that he wanted to become not only an astronomer but a famous comet hunter as well.   Discovering a comet in those days meant fame and fortune for whomever found one and Messier was definitely bitten by the comet-hunting bug.

In 1751, at the age of 21, Messier moved to Paris where he became the assistant to astronomer Joseph-Nicolas Delisle of the Naval Observatory.  The observatory itself was a rather humble affair located in the stair tower of the Hotel de Cluny, which had once been the residence of Benedictine monks, and, in terms of prestige, stood within the shadow of the French Royal Observatory.  The Naval Observatory and Delisle were not part of the in-crowd of European astronomy and Messier would have to work hard to become accepted by his more formally trained academic peers.

For seven long years Messier toiled away at his apprenticeship and he finally got his first real assignment in 1758 when Halley鈥檚 Comet was predicted to reappear.  Messier鈥檚 mentor had done his own calculations of the comet鈥檚 orbit and determined that it would make its closest approach to the Sun sometime in April of 1759.   Delisle assigned Messier the task of finding it before anyone else could.  He began hunting in the summer of 1758 and he stuck to his master鈥檚 predicted orbital path but he had no success until the night of January 21st, 1759.  Unfortunately it wasn鈥檛 where Delisle said it would be and Messier soon found out that a farmer in Saxony had beaten him to the punch by spotting the comet a month before on Christmas night of 1758.

Even more frustrating for Messier was the fact that his master would not let him publish an account of his independent discovery; Delisle did not want the rest of the scientific community to know that he had erred in his calculations.  Delisle finally allowed Messier to publish the news months later but the Royal astronomers were highly suspicious of the late publication and refused to acknowledge Messier鈥檚 discovery.

Prior to the 18th century comets were usually discovered with the unaided eye and Charles Messier was the first person to really apply a systematic approach to their discovery.  He would scan regions of the sky with a telescope looking for faint and fuzzy blobs of light that might be a comet.  After spotting such a blob he would then carefully record it鈥檚 position and then watch it over a period of many nights.  If it moved relative to the background stars then it was a comet, if not then it was something else.  The usual name given to these objects in the 鈥渟omething else鈥� category was 鈥渘ebula鈥�, which simply meant it was a faint, misty patch and no one really knew what it was.   The problem for Messier was that the night sky has a lot of these comet impostor objects and he began to get fed up with wasting so much time on them.  He decided that he should catalog all of these nuisance nebulae to save him and any other comet hunters from having to concern themselves with them.

Messier would go on to become the most famous comet discoverer of his time.  He was obsessed with finding these dirty snowballs in space, so much so that King Louis XV dubbed him the 鈥渃omet ferret鈥�.   From 1758 to 1804 Messier would spend 1100 nights diligently searching for comets, he observed 44 altogether, more than the total known before him.   He discovered 21 comets in total, 6 being co-discoveries.  His most famous find was the Great Comet of 1769, sometimes called Napoleon鈥檚 Comet because Bonaparte was born a week after its discovery and who, years later, would award Messier with the Cross of the Legion of Honour.  With these and other discoveries Messier finally became a member of the international scientific community and, eventually, he even gained acceptance among members of the French astronomy establishment.

After a long and fruitful life Charles Messier died on April 11th, 1817.   But in a twist of fate it turned out that we remember Messier today, not for his comet discoveries, but for his catalog of nuisance nebula objects.   You see, the great irony is, that in his attempt to create a list of objects that comet hunters should avoid he inadvertently created a catalog of some of the most amazing deep-sky objects the night sky has to offer.

Today the catalog contains a total of 109 celestial objects and while no one knew what they were in Messier鈥檚 time science and technology have allowed us to gain not only much better views than was available through 18th century telescopes but also a deeper understanding as to just what the objects are.

Here are just a few of my favorites.

Messier (or, M) 1, The Crab Nebula in the constellation of Taurus.   While Messier was searching for Halley鈥檚 Comet in 1758 he came across this faint and fuzzy blob and mistook it for the famous comet.   After spending several nights watching it to see if it moved against the background stars he came up with the idea for his catalog.  We now know that the Crab Nebula is the remnant of a supernova seen by Chinese astrologers nearly a thousand years ago in the year 1054 A.D.  Today we can still observe the cloud of gas and dust expanding out into space.

Messier 27, The Ring Nebula.  This small, glowing cloud of gas and dust represents the last gasps of a dying star similar to our own Sun.  The star鈥檚 core has ran out of fusible material, contracted in upon itself and become extremely hot.  This has resulted in the star ejecting its outer layers in a glowing shell of gas that surrounds the white-hot core.

Messier 42, the Orion Nebula and arguably the most spectacular of all the Messier objects.  M42 is a vast glowing cloud of gas and dust where stars are being born.  It is also the most photographed of any deep sky object.

Messier 45, the Pleiades star cluster in Taurus.  M45 is an open star cluster, a loose collection of hundreds of stars that were all born from within the same stellar nursery.  The radiation from these hot young stars has cleared away all of the nebula material from which they were born and they now sparkle like diamonds in the night.

Messier 13, the Great Hercules Cluster is a spectacular example of a globular star cluster.  Globular clusters can contain thousands or even a million or more stars all tightly packed together in a ball that is only a few hundred light years or so in diameter.    They are also very ancient with some clusters being estimated at around 12 billion years old, almost as old as the universe itself.

Messier 81 and 82, Bode鈥檚 Galaxy and the Cigar Galaxy in Ursa Major.  Both galaxies are about 12 million light years away and the thing I like best about them is that you can get both within the same field of view whether you are using binoculars or a small telescope.

Every amateur astronomer begins his or her adventures with a telescope by trying to see as many of the Messier objects as possible and during March or April every year astronomy clubs all across the northern hemisphere hold Messier Marathons in which participants stay up all night to try and see all 109 in a single night.  It鈥檚 both a daunting and grueling challenge to say the least and it鈥檚 difficult to say whether the participants are just dedicated or a little crazy.   Being an amateur astronomer myself I can say that it鈥檚 probably a little of both.  Either way, a Messier marathon is just a lot of fun and it gives amateur astronomers a chance to not only hone their observing skills but to also enjoy the company of their fellow stargazers while engaging in a bit of friendly competition.

So, merci mon ami Messier.  Even though your catalog serves an entirely different purpose now than the one you originally intended for it we astronomers are forever in your debt for cataloging this incredible assortment of celestial eye candy.

Until next time, get outside, look up, and wonder.

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FROM VENUS, WITH LOVE

Hello, I鈥檓 Darrell Heath with the 糖心Vlog传媒LR College of Arts, Letters, and Sciences, welcome to The Night Sky.

When I was a boy of about 10 or 11 I became hooked on Edgar Rice Burroughs鈥� John Carter of Mars novels.  For weeks on end I stuffed my head on these planetary science fiction adventures and craving more I then turned to his Carson of Venus novels.  Burroughs had a tendency to recycle his plots but I didn鈥檛 care, I just wanted more wild adventure stories that took place on other planets.

Whereas his version of Mars was that of a dry and dying world inhabited by an assortment of exotic aliens and creatures, his Venus was that of a tropical paradise.   According to Burroughs, Venus was a planet enshrouded by water-laden clouds and beneath those clouds was a world that was mostly ocean with a few landmasses covered in jungle.  What鈥檚 more there were giant reptiles aplenty and for a boy who was also in love with dinosaurs Venus seemed like the place for me.

On paper Venus and Earth do appear to be twin sisters of one another: both are very similar in size and mass with Venus being just a bit smaller, both have a similar surface gravity, and both possess substantial atmospheres and even clouds.  But there the similarities end.  As most of you already know the planet named for the goddess of love is downright nasty.

Orbiting spacecraft using ground penetrating radar as well a probes sent to the surface reveals a world more akin to Hell than paradise.  Venus鈥� surface temperature is a scorching 860 degrees Fahrenheit.   That鈥檚 hot enough to melt lead!  The atmosphere is so thick that were you able to reach the surface you would be crushed under pressure that is over 90 times what you experience here on Earth.  The Venusian atmosphere is mostly carbon dioxide and those clouds that perpetually enshroud the planet are not made of water vapor but are instead composed of sulfuric acid.  No oceans of liquid water cover Venus; its surface is a desolate landscape of scorched rock and thousands of dormant volcanoes.

But was Venus always this way and if not then what made it so inhospitable?

Many astronomers believe that during the first 2 billion years of its history Venus may well have contained oceans of liquid water.  In fact, it was this water that eventually led to the planet becoming the hellish world we know today.  But the instigator for the transition from paradise to Hell wasn鈥檛 the planet but the Sun.

Like any star our Sun has undergone changes during its 4.5 billion year history and will undergo more changes in the distant future.  Early on in its life the Sun was much dimmer and cooler than it is today and during this time Venus was on the edge of the habitable zone at around 67 million miles away.  But at around 2.5 billion years ago the Sun began to brighten and became much warmer.

Being much closer than the Earth is to the Sun Venus began to warm up and its water began to evaporate to form a thick cloud layer that enshrouded the planet.  Water vapor is a potent greenhouse gas so, while sunlight was allowed to penetrate the cloud layer, the much longer wavelength of infrared heat energy was prevented from escaping.   This made Venus even hotter and even more water vapor entered the atmosphere.  The result was a runaway greenhouse effect.  Eventually the surface became so hot that carbon was baked out of the rocks, which then entered the atmosphere to create carbon dioxide, another powerful greenhouse gas.  Venus鈥� fate was sealed and all the water on the surface boiled away.  Today we can find only traces of water in the atmosphere, the rest has escaped out into space.

In a surprise twist space probes have discovered that at about 31 to 40 miles above the surface there exist conditions that are remarkably Earth-like, in fact you will not find such hospitable conditions anywhere else in the solar system.  At these altitudes the atmosphere is actually breathable with a mixture of 21% oxygen and 78% nitrogen.  But if you plan to visit be sure and bring along the air conditioner because temperatures are at around 167 degrees Fahrenheit.

While human induced global warming will most likely not create conditions as extreme as those on Venus the planet still serves as a stark reminder of the dangers of dumping excess greenhouse gases into our own atmosphere.  Even a fraction of those conditions will have devastating consequences for life on Earth.

Whenever Venus is visible in our morning or evening sky it is often the brightest object visible outside of the Moon.   All this month you can spot the second planet from the Sun quite easily during the hours of dusk just around and after sunset low along the western horizon.    Be sure and look for the much fainter planet, Mars, next to it.  Early on in the month Mars will lie about 8 degrees above Venus but as the month wears on they will get closer and closer together.  On the nights of February 20th through the 23rd the two are less than one degree apart, a close pairing indeed!  On the 21st they are actually a half a degree apart and what鈥檚 more we will have a very lovely crescent moon that will be part of the western sky view as well.  When Venus and Mars are that close you will need either binoculars or a small telescope to split them apart optically.   Now, keep in mind that even though they are close together on the sky they are in fact separated by millions of miles in space.

That鈥檚 all for now but be sure and visit our web site for more astronomy news and information.  Until next time be sure and get outside to look up and wonder.

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Hello, I鈥檓 Darrell Heath with the 糖心Vlog传媒LR College of Arts, Letters, and Sciences, welcome to The Night Sky.

I imagine many of you have stepped outside on a cold winter鈥檚 night and noticed just how bright the stars look.   Part of this is due to the fact that the atmosphere is more transparent; there鈥檚 just less humidity and haze to obscure the starlight.  But it鈥檚 also due to the fact that our winter sky is filled with more bright stars and constellations than any other time of the year.  Some of the most prominent stars in our winter sky can be seen while facing south during the early evening hours this month and include Betelgeuse and Rigel in the constellation of Orion, Aldebaran in Taurus, Capella in Auriga, Castor and Pollux in Gemini, Procyon in Canis Minor and Sirius, the brightest star in our night sky within Canis Major.  Most of these stars make up a pattern known as the Winter Hexagon.  Such patterns are not constellations however; they are called 鈥渁sterisms鈥� and are made up of the stars from one or more of the official 88 constellations.   You already know one of the most famous of asterisms, 鈥淭he Big Dipper鈥� within the constellation of Ursa Major seen in our northern sky year round.  I suggest you spend a little time learning more about these different stars on your own as they offer a good survey of the types of things you can find within the stellar zoo.

For right now however I want to draw your attention to how, on some nights, these stars twinkle like flickering sparks of light in the dark.  All stars can be seen to twinkle at anytime of the year but it seems to be particularly noticeable on winter evenings and even more so with brighter stars than with dimmer ones.  Oh, and if you want to amaze and impress your friends you can use the more technical term of 鈥渁stronomical scintillation鈥� rather than 鈥渢winkling鈥�.

So, why do stars scintillate?   Take a deep breath.   There鈥檚 your answer: atmosphere.  We live on a planet that is insulated by layers of air with differing densities, temperature, and humidity and it鈥檚 always churning.   It鈥檚 turbulence within the atmosphere that makes the stars twinkle.   The photons emitted by the stars have been traveling unimpeded, in straight lines, across trillions of miles of vacuum but once they enter our atmosphere their path can become bent, or refracted.  Light refracts when it passes from one medium to another. You鈥檝e seen this effect before when a spoon appears to be bent inside a glass of water.  Of course it isn鈥檛 the spoon that鈥檚 bent, it鈥檚 just the way light is being refracted as it passes from the water into the air.   In the cold vacuum of space there was nothing to bend the starlight but inside our atmosphere there exists multitudes of tiny packets of air known as cells that are only a few dozen centimeters across and these cells are constantly moving around in all directions, more so when there鈥檚 lots of atmospheric disturbance.  The cells act like tiny lenses that bend the star鈥檚 light back and forth.   From our vantage point on the ground the star appears to twinkle.

If you are an especially good observer you might notice that stars low along the horizon seem to twinkle much more than do the stars overhead.  Not only that, but some of the stars are also changing colors.   When you look at any star while it鈥檚 low in the sky you are seeing it though a much thicker layer of air than when it鈥檚 directly overhead, and as it鈥檚 light is having to travel through more air before finally reaching your eye, it鈥檚 also getting refracted more and twinkles more conspicuously than does a star overhead.   To see the color change I suggest watching Sirius while it鈥榮 low upon the horizon during the early evening.   Finding Sirius is easy, it鈥檚 our brightest star, and if you draw a line through Orion鈥檚 belt stars, and extend it out and to the left, you will run right into it.  When Sirius is high upon the sky it鈥檚 light appears as an unchanging white, but when it鈥檚 near the horizon and there鈥檚 a lot of turbulence you can see it rapidly change colors from white to blue to green and red.   The white light of stars actually contains every color of the rainbow but if you pass the light through a prism you can split it into its constituent colors.   This is what happens as Sirius鈥� light passes through all of those cells of air in our atmosphere.   If the turbulence is especially bad it can refract the star鈥檚 light so much that Sirius looks like a disco ball as it changes colors in fractions of a second.   It鈥檚 not at all unusual for folks to report seeing a UFO when Sirius is so scintillating.

Now, you鈥檒l sometimes hear folks say that you can always distinguish a planet from a star by the fact that stars twinkle and planets do not.  This is mostly true but not always.  Around 8PM when Sirius is still low in the southeast look to the east to see the planet Jupiter on the rise.  In most cases you鈥檒l see that Jupiter鈥檚 light remains steady while Sirius鈥� may be flickering.  Planets don鈥檛 appear to twinkle because they are closer to us than the background stars.  While not apparent to the naked eye a planet is a disc rather than a pinpoint light source like a star is.  Remember, the cells of air in our atmosphere are usually only a few dozens of centimeters across and are too small to make the light from the planet鈥檚 disc scintillate very much but are just the right size to really distort the starlight.   However, on nights with lots of turbulence even Jupiter may appear to twinkle.   Last year at this time I recall trying to observe Jupiter through my telescope on a seemingly calm night.  The view through the telescope however told a different story.  Jupiter鈥檚 disc appeared to shimmer wildly and I couldn鈥檛 make out any of the planet鈥檚 distinctive features.  While twinkling stars can look very pretty they are a royal pain to both amateur and professional astronomers.   Twinkling stars means the seeing conditions are bad and you won鈥檛 be able resolve stars or planetary details through the eyepiece of a telescope.

Astronomers have had to be very creative in overcoming the limitations of trying to study the universe through an uncooperative atmosphere.

This is a photo of me at the Keck Observatory located 14,000 feet above sea level atop the extinct volcano Mauna Kea on the Big Island of Hawaii.  There are a number of good reasons to build observatories at such altitudes but one of the most important is that the atmosphere is very thin at these elevations and consequently starlight is not distorted as much as it would be at lower altitudes.
But we still aren鈥檛 completely free of atmospheric disturbances even at higher elevations so astronomers have had to become even more creative.   One of the most inventive and high tech methods astronomers use to compensate for atmospheric distortion is known as 鈥渁daptive optics鈥� and involves the use of lasers, deformable mirrors, and supercomputers.  To get clear, sharp images from the telescopes at the Keck Observatory astronomers fire a laser up into the atmosphere.  Their target is not a star but tiny atoms of sodium located about 60 miles up.   The laser excites the sodium atoms for a brief moment and when the atoms return back to their normal un-energized states they emit light.  In effect, astronomers are creating an artificial star, although it鈥檚 far from being a real star in any shape or form.   The light from this false star is analyzed by a computer to determine how the atmosphere is distorting it.  Once this is established the computer then sends instructions to the telescope鈥檚 mirror to change its shape in order to correct for the light refraction.   Over the past decade many other observatories have employed adaptive adaptive optics with much success.

Of course the ultimate way to get around the distorting effects of our atmosphere is to escape it altogether and send telescopes into outer space itself.   For 24 years now the Hubble Space Telescope has allowed astronomers to understand our universe in ways never before dreamed of.  It has helped us understand how galaxies evolve over time, given us data that has helped refine the age of the universe itself, shown us that supermassive black holes are a ubiquitous component of galaxies, revealed how planets form, and has helped us figure out the rate of expansion of the universe.  And the images acquired by the Hubble Telescope have inspired us, filled us with awe, and revealed to us just how beautiful and wondrous the universe really is.

Until next time, I encourage you to experience some of this beauty for yourself by simple stepping outside and looking up in both awe and wonder.

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