Universe Update, November 2010

The third Thursday of every month, the Morrison Planetarium hosts “Universe Update” at the 7:30 and 8:30 planetarium shows during NightLife. I select my favorite astronomy stories from the past month, and I give a brief run-down of current discoveries while taking audiences on a guided tour of the Universe.  As you may or may not know, the planetarium sports a three-dimensional atlas of the Universe, so we can take you places virtually while talking about the latest astronomy news.

I always start at Earth and work my way out to cosmological distances, so I’ll list the news stories in the same order—from closest to farthest from home.  (Sorry for the delay in posting, BTW; I’m new at this, and I managed to mangle all my formatting in my initial version of the following…)

First off, evidence that engineers have a sense of humor.  NASA plans to launch a satellite named “O/OREOS.” That’s an acronym, of course, which stands for “Organism/Organic Exposure to Orbital Stresses.”  Nothing awkward about that. Nope.  Anyway, the so-called nanosatellite looks to be about the size of a PS3, at least as far as I can tell from this image. The tiny package includes two separate experiments: the Space Environment Survivability of Live Organisms (SESLO) and the Space Environment Viability of Organics (SEVO).  Basically, the experiments will expose microbeasties and organic molecules to the environment of space, then see what happens.

In addition to launching pint-sized satellites, NASA has also taken to repurposing spacecraft for more extended missions.  The Spacecraft Formerly Known as Deep Impact got a new lease on life as EPOXI, yet another acronym (of sorts) which combines the two acronyms Extrasolar Planet Observations and Characterization (EPOCh) and the Deep Impact Extended Investigation (DIXI) in a manner that would surely confuse any linguist.  At any rate, the mission overcame its burdensome epithet to succeed in making up-close observations of a the comet Hartley 2 (Deep Impact’s original mission involved visiting the comet Tempel 1 and slamming an impactor into it to analyze the resulting debris, and you can compare the size and appearance of the two comets in this image). EPOXI observed “cosmic snow” spewing from Hartley 2, which makes it a much more active place compared to Tempel 1 and other comets.  Carbon dioxide appears to power these snow storms (I imagine shaking up a can of soda), which also distinguishes Hartley 2 from others of a cometary ilk.

And oh, yeah.  More evidence for water on Mars.  (No, really, it’s great that we’re finding more and more evidence:  it just seems like the same story over and over.) The poor little Spirit rover, trapped in place with one of its wheels stuck in soft sand, found evidence of subsurface water when it examined soil uncovered during its attempts to free itself. I mean, what else is it going to do, sitting there in one spot for so long?  May as well take a close look at what’s underfoot…

Meanwhile, in orbit around the Red Planet, the Mars Reconnaissance Orbiter observed silica on the slopes of a martian volcano.  The presence of silica implies that the region must have experienced a “wet and cozy past,” with conditions conducive to life.  A snazzy image shows a three-dimensional reconstruction of the volcano.

A little farther from home, the Cassini spacecraft has made extended observations of the planet Saturn, including measurements of the planet’s temperature.  Measuring the output of infrared radiation allows scientists to deduce how much energy flows from the planet, and it turns out that the flow is both uneven and unsteady. The southern hemisphere emits more energy than the northern hemisphere, and seasonal variations also surprised scientists.  Cloud cover may explain some of the disparity, but mover evidence will help clarify what’s going on.

(Also, FYI, the Cassini spacecraft went into “safe mode” in early November, but it will resume nominal operations just in time for Thanksgiving. Not that it has anybody to share turkey with, a billion miles from Earth, but hey, it should be thankful for getting powered back on!)

The Kuiper Belt resides in the Solar System’s Pluto-ish neck of the woods, and we keep identifying more icy dwarfs inhabiting the belt.  And we find out more and more about the individual members, too.  An announcement at the end of October describes measurements of the colors of these comet wannabes, and scientists were surprised by the diversity.  We might expect basic black to be the color of choice when exposed to the constant flux of radiation from the Sun, but it seems that a range of hues result from erosion or sandblasting of the Kuiper Belt objects.

The day of Universe Update, news outlets tittered with the announcement of an “Exoplanet from Another Galaxy.” (Which reminds me for some reason of Brother from Another Planet, a John Sayles film I highly recommend.) Anyway, this recent exoplanet discovery rightfully attracts attention for a variety of reasons. First off, its parent star looks like a red giant, which suggests that some of the exoplanet’s brethren may have gotten gobbled up in the past, and indeed, the planet may have spiraled into a closer orbit over time. Also, the parent star exhibits a high velocity relative to other stars in our galaxy, suggesting that it originated not from our own Milky Way Galaxy but from a galaxy gobbled up by the Milky Way. According to Rainer Klement of the Max-Planck-Institut für Astronomie (MPIA), “this cosmic merger [of the two galaxies] has brought an extragalactic planet within our reach.”

Happy birthday, SETI!  Not the SETI Institute, but the search for extraterrestrial intelligence itself… Fifty years ago, the astronomer Frank Drake conducted the first SETI experiment, Project Ozma. (Yes, “Ozma” comes from the book The Wonderful Wizard of Oz, and thus the subtext of odd names continues in this week’s Universe Update.)  In 1960, Drake listened for radio signals from extraterrestrial civilizations and launched a search that continues today.

Scientists announced the discovery of the youngest nearby black hole—only thirty years old, and a mere 60 million light years distant.  In 1979, astronomers observed a supernova in the spiral galaxy M100; as the third supernova discovered that year, it gained the moniker SN1979C (you do the alphabetical math).  After a dozen years of observing SN1979C in x-rays, it turns out to emit a constant stream of high-energy light.  The likely explanation?  A black hole formed in the wake of the supernova.

Way back when (well, 1974 if you want to be precise), Stephen Hawking proposed that tiny black holes formed shortly after the Big Bang might actually evaporate over time, through a process unsurprisingly dubbed Hawking radiation. Lo and behold, a group of UCLA scientists think they may have discovered evidence for these exotic objects, although their results seem to take the form of a terse and somewhat difficult pre-print. Trust me, if it pans out, it’s a pretty spiffy finding.

The Hubble Space Telescope imaged the core of the giant elliptical galaxy NGC4150, discovering a wealth of activity, with swirling dust and gas illuminated by a bunch of baby stars. That comes as a bit of a surprise, since elliptical galaxies basically qualify for retirement in cosmological terms—they have used up the gas and dust that they need to form new stars.  Thus, it seems that NGC4150 has recently gobbled up a neighboring dwarf galaxy, and we are now seeing the digestion taking place in the center of the galaxy.

Those rate as my favorite stories for the past month.  Stay tuned for next month’s “Universe Update.”

Ryan Wyatt, Director
Morrison Planetarium and Science Visualization