Written by Kelly Herbst, Astronomy Curator for the Virginia Living Museum. Updated every two weeks, more or less.

Wednesday, August 28, 2013

Hey there, LADEE!

Okay, the title works much better if you think of saying it with a nice Irish accent.

We're going back to the Moon!  Okay, it's with a robot right now, but hey, let's take what we can get!  LADEE, or the Lunar Atmosphere and Dust Environment Explorer, will launch from the Wallops Island Flight Facility here in Virginia on September 6th.  That means we should have a great view of the will much of the east coast of the United States, in fact.

The LADEE Spacecraft.  Courtesy Wikipedia.

Wait a minute...Lunar Atmosphere?  Yes, lunar atmosphere.  Most of the time, when we talk about the Moon, we say it has no atmosphere.  That's because for all practical purposes, it doesn't.  There's certainly nothing like air that we could breathe.  And yet, there are some tenuous gases around the Moon...and I do mean tenuous.  The pressure of the "lunar atmosphere" is less than one hundred trillionth of Earth's atmospheric pressure at sea level.  You don't get more tenuous than that!  It seems to mostly be comprised of argon, helium, sodium, potassium and hydrogen, most of which probably comes from outgassing from the Moon itself.  But we'd like to know more about this "atmosphere," where it comes from, and what effect it may have on any future (and perhaps permanent) missions to the Moon.

And then there's dust.  Dust is tricky stuff in space.  It can make for some real problems.  The Moon's surface is covered in dust - lunar regolith is essentially dust-sized particulates and they can get everywhere.  A major challenge for any equipment working in the lunar environment is how to deal with the lunar dust.  The more we know about it, the better we can plan to handle the dust as we eventually head back to the Moon, hopefully, to stay.

Dust may also be the answer to an enduring mystery that came out of the Apollo missions.  Apollo astronauts reported seeing mysterious glows and rays above the lunar surface.  These could have been caused by sodium ions...or they could have been caused by sunlight shining on dust in the lunar atmosphere.  LADEE will be seeking the answer to this enduring mystery.

A sketch made by Apollo astronauts showing the glows and rays observed above the Moon.  Courtesy Wikipedia.

Watch my blog for more information on when and where to look for LADEE's launch as we get closer to T minus zero.  If all goes well, on September 6, Virginia will be host to an amazing sight - and the start of a 3 to 9 month exploration of more mysteries of the Moon.

Until then,
Carpe noctem!

Sunday, August 18, 2013

COSMIC STRINGS ALERT: Nova Delphini 2013

Woohoo!  We got us a nova!

A nova is a small, usually white dwarf star which brightens significantly because a companion star dumps material onto it.  When this new material becomes hot and dense enough - WHAM!  Nuclear fusion suddenly begins again, making the once-dead little star come to life and produce a whole heck of a lot of energy all at once.  A white dwarf can go nova repeatedly - as often as the supply of fuel is replenished to sufficient levels by its companion.

Nova Delphini 2013.  Image courtesy Wikipedia.

That appears to have a happened to a star in the constellation Delphinus the Dolphin.  The once-invisible star has brightened dramatically over the last few days - and it is now at just about the limit of vision for the average skies in our area.  If the sky around where you are is relatively dark and uncluttered at night, you should be able to pick out a faint "new" star in Delphinus.

"New" is in fact the Latin translation of nova.  Early astronomers thought that what they were seeing was a new star bursting into life.  Today we know this is not the case, but the name persists.  And in one sense, it is a "new" star, since normally this little white dwarf cannot be seen with the human eye at all.

This uptick in brightness may only last for a few days, and fortunately for us, the nova is well-placed in our evening skies for viewing.  Don't miss your chance to see this beautiful object!  Once the sky is nice and dark, head outside to check out the area near the Summer Triangle for the nova.  The chart below will help you locate it.  Bring out a pair of binoculars or a telescope to help you, as even at this new brightness, the nova may be just on the edge of your vision.

A guide to finding Nova Delphini 2013.  Image from Universe Today, created in Stellarium.

Best of luck!  If you see it, leave me a message in the comments!
Carpe noctem!

Wednesday, August 14, 2013

No Stars Over Nashville

Howdy y'all!

Okay so after another missed post by the automatic poster, I give up.  And that's how I find myself sitting in a hotel room in Nashville, writing this entry.

I'll be on the road most of this month, actually.  Having a school-age child, this is our chance to go on vacation before the school year begins again.  So far, I've spent a week in Chadds Ford, Pennsylvania, and now I'm in the middle of a week in Nashville.

I grew up in New York City, where a night filled with stars meant you were either seeing a Broadway show or you were in the Hayden Planetarium in Manhattan.  I can remember being a kid and being so excited for summer and the return of the Summer Triangle - three bright stars that I could pretty reliably find in evening sky.  I knew the Big Dipper and Orion only from my many visits to the Hayden.  The Moon was a well-known friend, of course, and I could spot planets, but frequently couldn't tell which was which.

Since moving to Virginia, where the skies are much darker, even with as much growth as there's been in the Hampton Roads area, I've naturally come to know as much about the real sky as I do in the planetarium.  The real sky is different from the planetarium sky of course, because the real sky is...real!  It's big!  And things twinkle!  And you can see satellites and meteors and all sorts of stuff that's kind of hard (and often distracting) to simulate in the planetarium environment.

Whenever I travel, I try to take some time to check out the local skies, wherever I am.  Chadds Ford was a nice place to stargaze, once I drove away from the main roads.  I didn't take long to find an area with pretty much no lights at all and beautifully dark skies.  Wilmington, Delaware is the nearest major city, and the sky glow from it was largely unnoticeable thanks to some nearer object shielding me.  Sky glow, the excess light thrown up into the sky by artificial lighting used by people, is the stargazer's great nemesis.   It washes out the sky, and obscures from our view much of what we should be able to see.  So many of us now live near cities that most people, at least here in the United States, have never seen the Milky Way, the beautiful cloudy band of light that stretches across our sky every evening.  It's our view of our galaxy as seen from the inside, and it's amazing.  I got to see it in Chadds Ford, thanks to a clear night and a fairly open area with no streetlights.

Here in Nashville, I'm not so lucky.  Nashville is Music City USA, and it's a busy, fun, and exciting place.  But with all that comes the inevitable light pollution problem that so many have.  I've seen the Moon here thus far, but that's it.  The next two nights are supposed to be cooler and clearer than the sky has been so far - I'm hoping to spot a little more in the sky tonight.

Light pollution is a problem that can be solved - and so easily!  It even saves us money! All we need to do is make sure the lights we need for safety and security and fun are shielded - that is, they are protected so no light is wasted by shining up into the sky.  After all, light that shines up just lights us birds and airplanes and the sky, so why bother spending money on that?

Later this month, I'll be in Grenloch, New Jersey.  My folks live there, and I know those skies pretty well.  Sadly, the Garden State is losing its sky as rapidly as it loses its rural areas.  Here's hoping that someday we can reclaim those skies.  It isn't too late.

Wherever you go this summer, may the skies above be clear and light pollution free!
Until next time,
Carpe noctem (and yee-hah!),

PS: Hey!  Don' forget the annual Perseid meteor shower is underway!  We're officially past the peak, but you should still be able to see meteors in the evening any time after the Sun goes down.  The darker your sky, the more you will be able to see.  Just get outside and look!  No telescope or binoculars needed!