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Written by Kelly Herbst, Astronomy Curator for the Virginia Living Museum. Updated every two weeks, more or less.
Showing posts with label August. Show all posts
Showing posts with label August. Show all posts

Wednesday, January 2, 2013

Resolved

Happy New Year everyone!

I hope your 2013 has gotten off to a great start.  For many of you, that may mean making some New Year's Resolutions.  I've never been much for them myself...I often find my enthusiasm for them wanes rapidly after the New Year's celebrations are over.  But if you find yourself in need of some resolutions this year...I humbly present to you these recommendations.

New Year's Resolution #1: Resolve to be more in touch with the universe around you.
Back in the day, humans were very in touch with the universe.  It was our clock, our calendar, a source of wonder and the home of the gods.  Today, many of us go through our lives without ever taking the time to look up.  Make it a mission to spend some time under the stars this year.  We can help!  Every second Saturday of the month, the museum hosts a Star Party.  The first one in 2013 is on January 12 - we'll look forward to seeing you!  Star Parties are FREE and everyone is welcome.

New Year's Resolution #2: Resolve to see some shooting stars.
Virtually every year there's a really good meteor shower to see...and 2013 is no exception.  This year, the Perseids are on tap to put on an excellent show, and that's great news for all you folks who hate having to be outside in the freezing cold weather to do your stargazing!  The Perseids peak on August 12th, so you'll be able to spend a balmy evening in your shorts and t-shirt watching "stars" fall from the sky!  On that night, the Moon will be just past first quarter and will set early, so you can drag out a lawn chair and stare upwards for the rest of the night with nothing to dim your view of the heavens (just get away from any city lights near you).  Some models are predicting a bump up in rates for the Perseids this year, so this one could be pretty neat.  Remember - no telescope or binoculars are needed; the more sky you can see, the better.  Put your back to the constellation Perseus and enjoy the show.

A bright Perseid meteor streaks across the sky.  Image by Stefano DeRosa

New Year's Resolution #3: Resolve to use that telescope in the closet to see something cool.
So many of us have a telescope sitting somewhere gathering dust.  Well, this year, you need to get it out and have it set up and ready to go on Friday, October 11, no later than 11:30pm.  Point it at Jupiter as early as you can, and watch.  Slowly but surely, the shadows of not one, not two, but THREE of the largest Jovian moons will make their way across the giant planet.  A triple eclipse for Jupiter...a triple shadow transit for those of us here on Earth.  It should be a lovely sight in a good sized telescope.


A rare triple shadow transit on Jupiter on March 28, 2004.  Image by Sid Leach.

New Year's Resolution #4: Resolve to watch a rocket take off.
If you can get to Cape Canaveral on November 18th, you'll have the opportunity to do it in person!  If not, tune in NASA TV and watch the launch of MAVEN: the Mars Atmosphere and Volatile EvolutioN mission.  MAVEN will study the Martian atmosphere to see how the loss of materials to space has affected Mars over its long history.  Launches are always cool to watch, and this one should be no different.

An artist's conception of the MAVEN spacecraft orbiting Mars.  Courtesy NASA.

New Year's Resolution #5: Resolve to see the comet of the century...maybe...
There's already a buzz in the astronomical community about Comet ISON - it could be the most amazing comet North America has seen since Hale-Bopp...or it could fizzle.  Currently located beyond Jupiter, this newly-discovered comet is making its way toward a close encounter with the Sun.  If it holds together, it could put on an incredible show during the last two months of 2013.  Early predictions indicate that Comet ISON could reach negative magnitudes (bright like Jupiter or Venus), or even outshine the Moon (2nd brightest object in the sky!) and have a gorgeous tail visible to the unaided eye for weeks or even months.  Other early predictions say it could completely collapse under the pressure of the Sun's light and heat and be a total washout.  The only way to find out will be to watch the skies.

The orbital path of Comet ISON.  Courtesy NASA.
So there you have it - five astronomical things to resolve to do in 2013.  Whatever you choose to do, may 2013 be a year full of joy for all of us.

Carpe noctem!
Kelly

Wednesday, August 3, 2011

The Dog Days are Back

Hey everyone!

Well, here we are again.  It's August.  The weather is hazy, hot, and humid.  Going outside for more than about 4 seconds results in sticky wet clothes, lots of sweat, and generally feeling nasty really fast.  It is not, by any stretch of the imagination, an astronomer's favorite time of year.

And yet, there's still stuff to talk about, even if we'd rather stay inside while we do it!

Traditionally, August days are called the Dog Days of Summer.  The phrase refers not to the lolling tongues of dogs desperately trying to stay cool, but to the brightest star in the nighttime sky, Sirius.  It's the brightest star in the constellation Canis Major, the Big Dog, and therefore it is often called the Dog Star.

The star Sirius.  NASA

The ancient Greeks noticed that in August, when things were getting pretty hot, the star Sirius rose in the East just before the Sun, meaning that Sirius shares the sky with the Sun virtually all day.  Since Sirius is so bright, the Greeks figured it must be pretty close, and the extra heat in August was caused by Sirius adding its light and heat to the powerful rays of our own Sun.  The Romans and the Egyptians also shared this same belief - and in fact, the Egyptians were especially attentive to Sirius, as the Dog Days occured just before the annual flooding of the Nile.  Score one for the ancients, no?

Well, the ancients were unaware of just how far away stars are.  They were correct in their assumption that Sirius is pretty close to us - it's about 8 light years away, or 47 trillion miles.  As close as that is as stars go, that's still much, much too far away for Sirius to have any kind of effect on our weather.  The Sun is only 93 million miles away, and that's the cause of our weather changes.  The heat at this time of year is the result of the Earth's tilt - the Northern Hemisphere is tipped towards the Sun during summer, giving us long days and lots of intense sunlight.  No additional stars required.

Don't feel too bad for the ancients.  They might not have been right about everything, but they did hand down some wonderful stories and ideas that are still fun to share.  Take the exciting tale of Perseus, son of Zeus and legendary hero.  His story is best known today as the campy classic film Clash of the Titans (trust me, for maximum enjoyment, stick to the original, not the sad modern remake).  You might want to rent it around August 12, and enjoy a midnight movie at home.  When the film is over, head outside and look up.  You should be just in time to catch some of the annual Perseid meteor shower, which will peak around 2AM on the morning of August 12.  Meteors will seem to come from the direction of the constellation Perseus, so put him at your back if you can. 

The constellation Perseus.  NASA

Staying away from bright sources of light will also help...and the best way to enjoy any meteor shower is from the comfort of a lawn chair so you can watch the sky as long as possible.  The beautiful streaks of light you see are bits of Comet Swift-Tuttle disintegrating in the Earth's atmosphere.  Want more information on meteor-watching.  Come by the museum any day at 1:30PM for our Virginia Skies program - one of our staff astronomers will be happy to help you with your questions about meteor showers, or any other astronomical topic!

And, just in case you were wondering...that bright golden star in the West in the early evening is Saturn, still nicely visible.  Out a bit late and noticing a bright white star in the East?  That's Jupiter.  Enjoy!

Carpe noctem!
Kelly