Top Story: December 17, 2010

Universe Update, December 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.

In honor of the annual meeting of the American Geophysical Union (AGU) here in San Francisco, I’ll focus on several stories coming out of that gathering.  Because AGU gathers together a collection of geologists, climatologists, planetary scientists, etc., I’ll talk quite a bit about discoveries here in our own solar system.

During Monday’s AGU sessions, the International Dark Sky Association announced that city light pollution affects air pollution. It turns out that the atmosphere makes good use of nighttime darkness to break down chemicals from car exhaust and other anthropogenic sources.  After analyzing the role played by one form of nitrogen oxide, “the study’s first results indicate that city lights can slow down the nighttime cleansing by up to 7% and they can increase the starting chemicals for ozone pollution the next day by up to 5%.” So light pollution ain’t just bad for astronomers: it affects the rest of us as well!

How do you measure the strength of the magnetic field deep inside Earth?  You look at the most distant objects in the Universe!  A Berkeley geophysicist announced the first measurement of magnetic field in Earth’s core. In case you were wondering, it’s about fifty times stronger than the magnetic field at Earth’s surface:  we know that the force that causes compass needles point north originates in the core, but now we can better describe what happens inside our planet to maintain the all-important magnetic field (which also creates the magnetosphere that protects us from the solar wind). The tricky (and counterintuitive) measurement relies on the tiny influence exerted on Earth by the Moon, which changes our planet’s spin just enough to be detectable through radio observations of distant quasars. A clever and impressive observation!

Speaking of Earth’s magnetosphere… NASA released the first-ever image of Earth’s magnetotail created by The Interstellar Boundary Explorer (IBEX).  The images that accompanied the press release look like something only a space scientist could love, but they reveal some important features:  notably, a blob of plasma shoved around by Earth’s magnetic field, which could contribute to the phenomena known as the aurora, more familiarly called the “Northern Lights” in this hemisphere. IBEX pulled off a very tricky observation, allowing us to see something we’ve never before observed directly.

A little farther from home, Jupiter’s stripe has returned!

As we described in a spiffy Science in Action video, new computer models suggest that Saturn’s rings may have originated in the collision of a large moon with the planet. Gotta break some eggs to make an omelet, right?

NASA announced that the Cassini spacecraft has discovered a volcano-like formation on the surface of Titan, Saturn’s largest moon. Instead of spewing lava, this thing probably belches out ice, but it’s the first such formation discovered in the outer solar system. I have to admit that I get really annoyed by the exaggerated terrain depicted in the reconstructions of the volcano (such behavior in fact qualifies as one of my planetarium pet peeves), but an ice volcano on Titan?  I guess I can forgive the mediocre visualization.

Remember the Voyager 1 spacecraft?  Way back in the late 70s and early 80s, it sent back those images of Jupiter and Saturn that still grace many textbooks.  And now it’s speeding away from the Sun, headed out of the solar system.  About six years ago, it moved into a region where the solar wind grew denser, slower, and hotter. For the past few months, the probe has entered interstellar doldrums, where the solar wind has slowed to nothing.  One more step as Voyager 1 becomes an interstellar spacecraft…

Want to help scientists sift through the massive quantities of data coming from NASA’s Kepler Mission? You’re in luck!  The new Planet Hunters web site allows citizen scientists (that means you) to access light curves from various stars observed by Kepler. As described on the site:  “The Kepler team’s computers are sifting through the data, but we at Planet Hunters are betting that there will be planets which can only be found via the remarkable human ability for pattern recognition.  This is a gamble, a bet if you will, on the ability of humans to beat machines just occasionally. It may be that no new planets are found or that computers have the job down to a fine art. And yet, it's just possible that you might be the first to know that a star somewhere out there in the Milky Way has a companion, just as our Sun does. Fancy giving it a try?”  If your contribution leads to the discovery of an extrasolar planet, then you can even get your name on the resulting scientific publication.

And of course, there’s that arsenic story. We talked about it in Science Today right when the story broke and before the uproar ensued.  Bacteria discoverer Felisa Wolfe-Simon continuously posts to her blog with updates on the controversy, including a Q&A response posted just yesterday. Hard to know what to think at the moment, but time will tell. Paul Davies of Arizona State University wrote an article for the Wall Street Journal in which he reveals that, “What few people know, however, is the story behind the initials for her GFAJ-1 microbe, the first known organism to depart from the usual chemical formula for life. GFAJ stands for ‘Give Felisa a Job.’”  He concludes by expressing “little doubt” that someone will.

The Atacama Pathfinder Experiment (APEX) is a prototype for a much grander collection of telescopes to be built in the Atacama Desert. What’s a prototype telescope to do, however, if not a little research?  APEX has proven its mettle by making some key observations to help understand how stars form in Giant Molecular Clouds.  Tantalizing but very preliminary results.  (BTW, I’ll just mention that we show astrophysical simulations of the process of star formation in our new planetarium show, Life: A Cosmic Story.  Just FYI.)

I’ll finish by noting that I’m now attending the Future of AstroComputing Conference at the San Diego Supercomputer Center. Astronomers and computer scientists are gathering to discuss the latest tools and techniques for simulating the Universe using nothing but the laws of physics and massive computer power!  It’ll then be our job at the planetarium to visualize all the exciting results.

Ryan Wyatt, Director
Morrison Planetarium and Science Visualization


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