Fast Times Over East Coast Skies

Did you see it?

Last Friday, I got a phone call around 9pm from one of our local television stations.  They were getting lots of calls about some kind of meteor or something being seen in sky from all over the area.  Did I know anything about it?

Sadly, I'd been in my house all evening and missed the show.  But a quick internet search (oh whatever did we do before the internet!?) told me all I needed to know...people from Canada to Florida had seen a fireball...a dramatic meteor that lit up the skies all over the East Coast of the United States.

Two images of the East Coast Fireball from an astronomy camera in New York.  Images by Carl Fuller.

Since big sky rocks have been much in the news lately, I thought I'd use this week's post to define a few terms that have been tossed around of late.  I've got five of them for you, and once you've learned the differences between them, you too might get a phone call from a tv station, asking you for your expert opinion!  Okay, maybe not...but at least you'll know what these folks are talking about...and when they slip up and use the wrong word.

Let's start with the most common word: meteor.  A meteor is the streak of light created when a piece of material (usually rock and/or metal, but sometimes ice as well) comes in contact with the Earth's atmosphere.  The rock rubs against air molecules as it moves, generating lots of heat via friction.  This heat makes the air the rock passed through glow - and that's the streak of light we call a meteor.  The rock itself is not the meteor - in fact, we call it a meteoroid.

A meteorite is a piece of rock or metal that has traveled through the Earth's atmosphere from space and survived creating a meteor.  It crashes into the ground (sometimes creating a crater - a hole in the ground where it hit), and once the rock is on the ground, we call it a meteorite.  Finding a meteorite after seeing the meteor is very rare.  The vast distances involved often make it very difficult to judge where such an object may have landed.  There were early reports of the meteor on Friday having hit somewhere on the border between Maryland and Virginia, but this is extremely unlikely.  NASA has since analyzed the reported sightings of the meteor and they believe that any material that survived the passage likely fell into the Atlantic Ocean.

A meteorite nicknamed "Black Beauty."  The rock is believed to be from Mars, and landed in North Africa here on Earth.  The rock has been cut open and polished to reveal the inner structure.  Image courtesy NASA.

Okay, that's the big three.  But there are two more terms we need to come to grips with, and they've been tossed around a lot in recent days.  Some meteors are very bright - like the one that lit up the skies last Friday.  When a meteor is brighter than any of the planets (that is, brighter than Venus, the brightest object in the sky after the Sun and Moon), we call it a fireball.  Fireballs can be quite spectacular - often they show colors, since a chunk of material big enough to generate that much heat is going to be cooking lots of different materials - both on itself and in the air.  Such superheating can cause different molecules to glow with different colors of light.  Many people saw different colors in the trail of the meteor on Friday - and indeed, it was bright enough to qualify as a fireball.

Finally, the word bolide often comes into play when we talk about really bright meteors.  A bolide is a fireball that ends with an explosion - the rock becomes so superheated it detonates and explodes.  Such explosions are often accompanied by noises.  While several people reported seeing the Friday meteor fragmenting (bits and pieces may have been coming off), and some did report hearing noises accompanying the meteor's passage, the rock did not explode.  So it was not a bolide.  The recent fireball over the Siberian region of Chelyabinsk - that was indeed a bolide.  And a big one too.

So there you have it - you are now ready to speak with confidence about any shooting stars you might happen to see in the evening sky.  Did you see the one last Friday?  Leave a comment and tell me about it!

One more thing - I hope you got to see Comet PanSTARRS.  One of our wonderful volunteers did - and here's the photo to provide it!  Thanks to Mark Jablow for letting me use his beautiful picture.

A beautiful image of Comet PanSTARRS just after sunset.  Image by Mark Jablow.

Spring Break is coming for our area - so enjoy!  The museum will be open every day and we've got a full schedule of planetarium shows to keep the kids busy - hope to see you here next week!
Until then,
Carpe noctem!
Kelly

It's a bird...it's a plane...it's a COMET!

Greetings astronomy fans!

Well, it's here!  The first of the two comets touted to put on great shows in our skies this year.  Comet PanSTARRS has arrived!

Yep.  It's here. 

Okay, sorry if I sound a little bummed.  But I'd give my right arm to be in the southern hemisphere.  They've had extraordinary views of Comet PanSTARRS for quite some while now...and Comet Lemmon too!  And Comet McNaught last year!  It's been a veritable comet bonanza for our friends down under...and dang it, I am jealous!

But all is not lost here in the great white North.  I tried to see Comet PanSTARRS last night, but lingering clouds and light pollution made it impossible (I did see a fantastically young crescent Moon, however - youngest I've ever seen!).  But it should get easier tonight, as the comet is inching itself away from the Sun day after day.  That's going to both help (further from the Sun means it will be in a darker sky and easier to see) and hurt (further from the Sun means the comet itself will be a dimmer object) - but over the next couple of days we'll have our best chance to see this little interloper.  So how do we do that?  Here are some tips!

• Find a location with as little light pollution as possible.  Get away from as many city lights as you can.
• This same location also needs to have as flat a western horizon as possible.  The more sky you can see to the west, the better.
• Start looking to the west just after sunset.  Focus your attention to the left of the brightest sunset glow.
• Look for a very slender crescent Moon.  It will be up and to the left of the sunset.
• Once you see the Moon, look between the Moon and the sunset glow for the comet!

A finder chart for Comet PanSTARRS.  Courtesy space.com.

Trust me, it will not be easy to see.  Binoculars may come in handy, but use them carefully and ONLY after the Sun has completely dipped below the horizon.  Seeing a comet is not worth losing an eye for.

A camera will help a lot, if you are confident enough to try it and have one of those "old-fashioned" cameras you can force to leave the shutter open for more than a tenth of a second.  Witness the power of the two-second exposure:

Comet PanSTARRS from Louisiana on March 12.  Image by Mike B. Courtesy Cloudy Skies Telescope Reviews.

So, sadly, Comet PanSTARRS is fainter than we hoped it would be by now.  Comets are tricky beasts - chunks of ice and rock left over from the early days of the solar system's formation.  When they dive close to the Sun like this one has, the ices warm and turn directly to gas, creating an often intricate and beautiful tail of materials stretching for millions of miles.  But the brightness of a comet is determined by the amount of ice as compared to rock (ice is shiny and bright and rock is dull and dim), so there's never really a good way to know if a comet is going to be bright or not...until it arrives.  Also, this appears to be Comet PanSTARRS first (and possibly only) trip close to the Sun, so the intense heating may have driven all the ices off, leaving not much left for us to see now that the comet has rounded the Sun.

I wish you all the best of luck in your efforts to see Comet PanSTARRS...and never fear, there's still Comet ISON to come later this year.  It's being touted as the "Comet of the Century" - but of course, we'll just have to wait and see.

Until next time,
Carpe noctem!
Kelly

What's Up?

Well, hello.

It's been an eventful time in the astronomy business, thanks to a chunk of rock that decided to scare the living daylights out of a whole lot of people living in Siberia.  Amazingly, they seem to like air-bursting asteroids...once again, just like in 1908, a chunk of space rock exploded rather than impacting.  Since this one did so over a city, many people were injured when they rushed to look out their windows to see what the bright flash of light was.  Once the shock wave hit, the windows shattered, glass went flying, and many people were hurt.  But fortunately, I do not believe there were any deaths associated with the event.  But my goodness, it must have been quite scary to experience that first hand.  We talked about the 1908 event in our previous chat...when I wrote that I had no idea it would be happening again so soon!

The fireball over Siberia on February 15, 2013.

Anyway, let's turn ourselves to a calmer exploration of the sky.  It's been a while since I wrote a nice, simple post about things appearing in the skies above, so I think it's time to do that again.

The early evening skies are currently dominated by the largest planet in the solar system - Jupiter.  Shining brighter than all the visible stars, Jupiter is easily seen high in the southwest after sunset.  It's currently located in the constellation Taurus the Bull, right behind the bull's V-shaped face.  Taurus, of course, is facing off with Orion the Hunter, brightest constellation of our sky and easily visible high in the south.  So just by looking southward after sunset you should be able to quickly find the seven bright stars of Orion.  Use the belt of Orion (three stars in an almost perfect straight line) to find Taurus by following the line it makes away from Orion towards the right.  The belt will point you to the brightest star of Taurus, reddish Aldebaran.  This is the upper left point of the V of Taurus' face.  Right next to the V will be Jupiter, almost shocking in its brightness.

Following Orion's Belt to Aldebaran, the red right eye of Taurus the Bull.  In February of 2013, Jupiter is located between the V of Taurus' face and the Pleiades.

Jupiter is an incredible world.  Ten times bigger than our own planet Earth, Jupiter is a gas giant and the largest of the solar system's planets.  Even so, it is still much too small to be a star...Jupiter would have to be 10 times again as big as it is to become a star like the Sun.  The gravity of mighty Jupiter holds over 60 moons in orbit around the massive world, and even supports a tiny, thin ring system, completely invisible from Earth.  Only visiting spacecraft have the opportunity to see the rings of Jupiter, and they have fortunately sent lovely pictures back to us here on Earth.  Known from ancient times, Jupiter has long fascinated us, and it has been the target of numerous missions including the Voyager space probes and the Galileo spacecraft.  Another mission, Juno, is on its way, with a planned arrival in July of 2016.

The giant planet Jupiter.

The only other planet currently visible to us is Saturn, which graces the early morning sky before the dawn.  You'll see Saturn as a golden-yellow star-like object shining in the south before the Sun rises.  A pair of binoculars is all that is needed to reveal the lovely Saturnian rings, but you will need to hold them very steady.  A tripod will serve you well.  And be prepared to get up quite early - 5AM is the best time to see Saturn these days.  If you'd rather see it at a more convenient time...wait a few months.  Later in the year, Saturn will become an early evening object rather than an early morning one.

Saturn and its amazing ring system.

So everyone take a deep breath, relax, and enjoy the sky.  I promise, despite the events of recent days, the world is not coming to an end.  Hopefully the sky will give us a few days to catch our breath before the next potential big event - Comet PANSTARRS.  If the comet becomes something worth venturing outside to see, I'll put out a Cosmic Strings Alert to let you know.

Barring that, I'll see you in two weeks!
Carpe noctem!
Kelly