Monday, January 5, 2009

Astronomy is truly a science that takes you places.  At one level, it has brought ME to Long Beach, CA to hear about the latest and greatest astronomy discoveries. At another level, it is bringing us (scientists, writers — and  ultimately our audiences) out to the most fascinating places in the cosmos.

“Where?” you ask.  How about the core of the Milky Way Galaxy? Q.D. Wang of the University of Massachusetts at Amherst used the Hubble Space Telescope to make an infrared mosaic of the center of our galaxy.  It’s a beautiful panoramic view that takes in an area of space measuring 300 x 150 light-years.

The core of the Milky Way in an infrared mosaic from Hubble Space Telescope. (click to embiggen)

This is a “false-color” image taken through a filter that reveals the glow of hydrogen gas heated by winds from new stars revealed as a new population of massive stars at the core. And the cool thing is that this is the sharpest infrared picture ever made of the galactic core.

Astronomers are looking at this region to understand how massive stars form and what they do to their local enviroment during their tempestuous birth process. If we can understand how it works in OUR galaxy then we have insight into how it works in the cores of other galaxies, particularly the active ones.  Read more about this fascinating image at at the Space Telescope web site.

This 0.6 by 0.7-degree infrared photograph of the galactic center shows a large population of old, red stars. However, the discovery of two young protostars within a few light-years of the center of the Milky Way shows that stars can form there despite powerful gravitational tides due to the supermassive black hole. Credit: 2MASS/E. Kopan (IPAC/Caltech)

Now, looking at the center of the galaxy is difficult, since it’s shrouded in dust clouds. The good news is that we can plumb those depths using infrared and radio telescopes. Astronomers at Harvard-Smithsonian Center for Astrophysics and the Max Planck Institute for Radio Astronomy have used the Very Large Array in New Mexico to study young stars that really shouldn’t be there.

This is because the core of the galaxy is not a gentle creche where young stars should be able to form. It’s wracked with powerful radiation and gravitational tides stirred up by the four-million-solar-mass black hole that’s hidden at the core. It’s a place where stars go to get gobbled up, not get born.

So, nobody’s sure how a pair of protostars started to form at a spot only a few light-years from the galactic center. What this tells us is that this place, as wild as it might be, can still nurture star formation. Now astronomers will spend time figuring out how and why this is happening.

Artist's Conception of our Milky Way Galaxy: Blue, green dots indicate distance measurements. CREDIT: Robert Hurt, IPAC; Mark Reid, CfA, NRAO/AUI/NSF

This scenario may suggest that star-forming clouds may be much denser than we thought.  For more information, check out the story here.

Continuing our look at the Milky Way, the folks at the National Radio Astronomy Observatory are looking at our galaxy using the Very Long Baseline Array radio telescope and what they’re finding is redefining what we know about our galactic home. Essentially, the Milky Way is rotating faster, is heavier, and is more likely to collide with other galaxies than we used to think.

You can read more about their findings at the link above, but just to give you an example of what they’ve found: at our location in the galaxy — some 28,000 light-years away from the core of the galaxy — we’re speeding along at 960,000 kilometers per hour (600,000 miles an hour).

An asteroid bites the dust around white dwarf star.

A little closer to home, astronomers continue to focus attention (and detectors) on exoplanets — worlds circling other stars.

The white dwarf GD40 and five other similar type stars came in for some attention by Mike Jura of the University of California, who used the Spitzer Space Telescope to study the remains of asteroids chewed up as the stars went through their red giant phase and then shrank down to  become a white dwarf. That chewing action generated dust, which can be spotted with infrared-sensitive detectors. A star with MORE dust around it is “brighter” in infrared than a star with NO dust.

Ultimately, what their research suggests is that the same materials that made up our planet and other rocky worlds may be pretty common in the galaxy and the universe. You can read more about their work here.

NGC 2362 This photograph from NASA's Spitzer Space Telescope shows the young star cluster NGC 2362. By studying it, astronomers found that gas giant planet formation happens very rapidly and efficiently, within less than 5 million years, meaning that Jupiter-like worlds experience a growth spurt in their infancy. Credit: NASA/JPL-Caltech/T. Currie (CfA)

One of the more intriguing stories is about how baby Jupiters form around other stars.

It turns out that, according to scientists at the Harvard-Smithsonian Center for Astrophysics (who used the Spitzer Space Telescope to look at stars in the cluster NGC 2362 to detect infrared signatures of active planetary formation) a Jupiter-type planet has a pretty short time frame to form before the dynamics of the system shut off the process.

For our solar system, that means that Jupiter took only 2 to 3 million years to spring into being, whereas Earth took 20 to 30 million years to aggregate and solidify. Read more here.

Finally (for now, anyway), I got a press release detailing the upcoming WISE mission, which will provide a highly detailed all-sky survey in the infrared, from 3 to 25 microns. It’s supposed to launch in 2009 and will map the sky for at least seven months.  The scientists who use this instrument hope to find the most luminous galaxies in the universe, find the closest stars to the Sun, detect most of the asteroids in the Main Belt, and do a number of different studies of planetary discs around other stars.

Check out the WISE web site for more details.

Okay, there’s more to come, so stay tuned!

The World Series of Astronomy

I’m here in Long Beach, California at the American Astronomical Society meeting. The sessions start this morning, but we’ve already been at our meetings since yesterday morning. Lots to do and see! I will be putting up a more extensive blog posting later today, focusing on the day’s big news. Just to give you a taste of what’s to come: today we’re hearing news about exoplanets, brown dwarfs, a new discovery in the Milky Way, the festivities on store for the International Year of Astronomy, and the debut of a TV special about 400 Years of the Telescope.

So, stay tuned!

Mars 2019? 2029?

Will future Mars explorers see this scene before leaving their orbiting craft to land on the surface of the Red Planet? (This simulated view (created by Carolyn Collins Petersen) from Mars orbit is based on an ISS image posted at Astronomy Picture of the Day on December 30, 2008 and a Mars Global Surveyor image of dust storms at the Martian poles.)

A few days ago the folks at Astronomy Picture of the Day had a nice shot of an astronaut looking out the window at Earth from the International Space Station. Oddly enough, the just the other night, I had a dream about flying over the surface of Mars, and so when I saw the ISS picture, I thought back to that dream.

The dream of going to Mars is one that a lot of us have had for many years.  Many of the missions we see going on today are based on planning sessions that first occurred back in the 1980s, and now — decades later those spacecraft are doing the jobs we dreamed they’d be doing.

I don’t doubt that sometime in the next decade or two, the first Mars explorers will leave Earth to head for the Red Planet.  If they do, they’ll probably spend some time in orbit around the planet before heading to the surface. And, as such, I imagine that the scene from ISS that so caught my attention may well get played out for real by our children or their children — but high above Mars instead of Earth.

It’s Not Just About the Neighbors

A while back, I wrote an article for a book called State of the Universe 2008, and in it I discuss how some local astronomers were hunting for the very faint and elusive signals from the 327 MHz deuterium line out in space. This may sound rather esoteric — and it is if your life doesn’t revolve around trying to find out how much deuterium is left over in the cosmos after 13.7 billion years of stellar formation (which destroys deuterium).  For astronomers however, this is an important quantity to know since all the deuterium that ever existed in the cosmos was made in the Big Bang. If you find deuterium in great quantities somewhere, then it’s a pretty good sign that there’s been no stellar activity to suck it up.

The signal for deuterium (327 MHz) is detectable, but only just barely. And, if there’s any kind of radio frequency interference (RFI) in the vicinity of the detector, then it wipes out the deuterium signal. And I do mean ANY kind of signal — including RFI from sound systems, door bells, radios, cell phones, and answering machines.  The folks at MIT Haystack Observatory built a deuterium array and then spent months “mitigating” RFI from the nearby homes. It was worth it: these scientists were the first to detect and confirm this material.

But, they aren’t the only radio astronomers to be affected by nearby noise. Just like radio astronomers around the world, the folks at Greenbank, West Virginia (home of a major radio observatory) are constantly fighting RFI from things as simple as a car engine or a heat pad on somebody’s bed.  The signals they track down from earth-based sources are often more than strong enough to wipe out the faint frequencies emanating from distant pulsars and other cosmic sources.

This is why radio observatories have radio-quiet zones around them. And inside those zones, people can’t use technology that interferes with the faint signals from space. I’ve visited facilities where we’ve been asked to turn off cell phones, not use digital cameras, and refrain from turning on the wireless transmitters on our laptop computers. As annoying as it might be to visitors or the neighbors, having an RFI-free environment for science is important. The alternative is to move the observatories away from where they are (with the concomitant loss of jobs, etc.) and try to find other radio-quiet places (which the folks who are building the MWA and ALMA are doing). On a planet where there’s hardly anywhere left unexplored and unsettled, that’s getting to be a tough (and expensive) proposition.

Space Weather via Vodcast

Space Weather FX: the Vodcast Series

The third episode of our epic series on space weather, produced in conjunction with MIT’s Haystack Observatory, just got posted on the SWFX web site.  This is very timely, since I’m heading out to Los Angeles on Saturday for the American Astronomical Society meeting, where I’ll be giving a progress report on the whole SWFX project.

Each episode aims to present the basics of space weather in an approachable style in three minutes (although the first one came in a little longer because it was an overview).

Think of the episodes as bite-size tastes of the causes and effects of space weather. Some also focus on the many ways that atmospheric scientists study what happens to our planet — and our technology — when the Sun burps up a little space weather.

So, go check ‘em out!  I’ll write more about these episodes as the project progresses, and if you’re an educator, we’ll have some educational use feedback forms posted in a few weeks for your use.  Happy viewing!