The third Thursday of every month, give or take, Morrison Planetarium hosts “Universe Update” at the 6:30 planetarium shows during NightLife. We select our favorite astronomy stories from the past month, and give a brief run-down of current discoveries while taking audiences on a guided tour of the Universe.

We always start at Earth and work our way out to cosmological distances, and we’ll list the news stories in the same order—from closest to farthest from home.

Let’s start at Mars. Curiosity, the latest addition to our growing team of Martian rovers, landed on the Red Planet just a few months ago.  Previous landers sent back pictures and performed basic measurements, but Curiosity brought an entire geology and chemistry lab on a 225-million-kilometer expedition to Gale Crater, where the rover is using its instruments to search for evidence of Mars’s past.

In its “rocknest,” Curiosity found wind-swept dunes containing material similar to volcanic soil in Hawaii.  After vaporizing samples with its onboard laser, Curiosity’s CheMin instrument then used X-ray diffraction to search for clues to understanding the history of Mars’s atmosphere.  Evidence suggests that Mars once had a much thicker atmosphere, which disappeared a long time ago, leaving the thin layer we observe today.  As previous landers found layers of frozen water beneath Mars’s surface, Curiosity is taking the next step, equipped to hunt for methane, an organic molecule that’s a good indicator of life.  So far, Gale Crater seems devoid of this malodorous precursor, but Curiosity has two years and many kilometers of Martian soil to cover.

Our next stop is the giant asteroid Vesta: over 500 kilometers in diameter (the distance from San Francisco to Los Angeles), it’s the second-largest asteroid in our solar system.  The Dawn mission photographed it for over a year, looking at Vesta as a good example of what Earth may have looked like when it was just a wee baby protoplanet.  The big differences between light and dark in these photos puzzled scientists, since asteroid terrain isn’t usually so varied.  Space weathering should homogenize the surface, leaving a matte gray all over the surface.  But scientists now think that the dark material comes not from Vesta but from 300 smaller asteroid impacts over the last 3.5 billion years, each of which brought material such as the metallic dust, carbon, and hydrated minerals (minerals containing water) Dawn detected.  This mélange can account for the difference in light and dark areas, wrapping Vesta in powdered asteroid debris, one-to-two meters thick.

With a constant influx of data, astronomers are discovering new exoplanets faster than ever.  Re-examining old data can produce useful results, too, and astronomers have just announced that a planet somewhere between Earth- and Neptune-sized is orbiting HD 40307.  Despite only being three quarters as massive as our Sun, this star hosts six planets in total.  Most importantly, the new planet is orbiting right in that habitable sweet spot: not too cold and not too hot, this is a strong contender to have liquid water, that necessary ingredient for life on Earth (and very possibly elsewhere).

Our view of the stars from Earth is strictly two-dimensional, and even with visualizations like the planetarium’s Digital Universe, we still rely on our Earth-bound view to determine distances to objects in space.  A new image (see above) from a 340-megapixel camera on a telescope in Hawaii has found a heretofore unidentified cluster of stars in the familiar Orion constellation.  The most studied part of our night sky, the Orion Nebula turns out to have many layers, and the stars we see in the middle are in fact older stars closer to us than we previously suspected.

Two twelve-billion-year-old supernovae live far, far from our starting point on Earth: because looking out into space also means looking back in time, the Universe has changed a lot since these stars exploded, so it’s hard to give you a distance in kilometers or even lightyears, but one of them holds the record as the most distant supernova yet observed.  Needless to say, these are very, very old explosions that came from even older, supermassive stars, the likes of which don’t exist in the nearby, more recent Universe.

As the Universe continues to accelerate outward, the light we can see here on Earth fades into the cosmos.  In a few billion years, information from these distant galaxies simply won’t make it to Earth anymore, and we’ll be living in a rather empty neighborhood.  The parallels with the economic downturn are a little alarming, and a press release from a group of European cosmologists hammers it home.  It turns out that stars in the Universe are only forming at 1/30 the rate they once were: a cosmic market crash that looks to continue till the end of time.  The Universe seemed to peak about 11 billion years ago… Let’s hope the same isn’t true for the American GDP!

Dan Brady is a planetarium presenter at the California Academy of Sciences. He earned his BS in Physics from UCLA and has taught science since 2008.

Image: CFHT/Coelum (J.-C. Cuillandre & G. Anselmi)

The third Thursday of every month, the Morrison Planetarium hosts “Universe Update” at the 6:30 planetarium show 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.

Fourth graders from the Emily Dickinson Elementary School in Bozeman, Montana, proved themselves more creative than NASA engineers! Crazy rocket scientists named their two lunar-orbiting spacecraft “GRAIL-A” and “GRAIL-B” (where, of course, “GRAIL” is an acronym, which stands for “Gravity Recovery and Interior Laboratory”). The elementary school students selected the names “Ebb” and “Flow,” which NASA selected as the winning contribution in a nationwide contest. The GRAIL mission measures the ebb and flow of gravity, in a sense, as the two spacecraft orbit the Moon and measure variations in its gravitational pull. From the GRAIL website:

As they fly over areas of greater and lesser gravity, caused both by visible features such as mountains and craters and by masses hidden beneath the lunar surface, they will move slightly toward and away from each other. An instrument aboard each spacecraft will measure the changes in their relative velocity very precisely, and scientists will translate this information into a high-resolution map of the Moon’s gravitational field.

A little farther from home, new reports from a comet impact on the Sun that took place last July. We like to describe comets as “dirty snowballs,” and as you might imagine, a comet getting too close to the Sun stands a snow ball’s chance in… Well, a million-degree plasma irradiated by incident solar flux. The comet evaporated over a period of about 20 minutes, and as described in a paper that appears in today’s Science magazine, it probably measured between 150 and 300 feet across and had a mass equivalent to an aircraft carrier. According to Karel Schrijver, a solar scientist at Lockheed Martin in Palo Alto, the comet moved speedily to its demise: “It was moving along at almost 400 miles per second through the intense heat of the Sun—and was literally being evaporated away.”

A fair bit farther from the scorching heat of the Sun, the Dawn spacecraft is sending back gorgeous images of the asteroid Vesta, including this gorgeous snapshot of a crater on the asteroid’s surface. Dawn has entered a low-altitude orbit that gives it a close look at the potato-shaped planetoid. Learning more about such objects should help us better understand the formation of the solar system, and after its stay at Vesta, Dawn will move on to Ceres, the dwarf planet (like Pluto) that resides between the orbits of Mars and Jupiter.

Beyond our own solar system, of course, we are rapidly discovering planets in orbit around other stars: these extrasolar planets (or exoplanets) now number in excess of 700, and astronomers find more all the time.

As I described in one of my updates from the American Astronomical Society meeting last week, astronomers have announced the discovery of the most compact extrasolar planetary system yet detected. Looking at the KOI 961 system side-by-side with Jupiter and its major satellites strikes me as a particularly illuminating comparison: only 70% larger than Jupiter, the host star (the smallest known to have planets) has at least three planets (the smallest yet found) in orbit around it, the smallest of which is about the size of Mars. John Johnson, an astronomer at Caltech, announced the superlative system last week, and on April 2nd, he will give a talk in the Morrison Planetarium as part of our Benjamin Dean Lecture Series, “The Quest for Habitable Planets Orbiting Red Dwarfs.”

And astronomers have help in their search. Just this week, we had a glimpse into the democratization of astronomy… Viewers of a British television program(me) may have discovered a new exoplanet! Evidence from the Kepler mission suggests the existence of a Neptune-sized planet around the star SPH10066540, orbiting every 90 days at a distance equivalent to Mercury from our Sun. The discovery awaits confirmation, but you don’t have to watch telly in the U.K. to join in the search for such objects. You can go to the PlanetHunters website and start sifting through Kepler data in hopes of finding a planet of your own…

In another of my posts last week, I mentioned the spectacular new Spitzer image of Cygnus X, a massive star-forming region in the constellation (you guessed it) Cygnus. Ten times the size of the Orion Molecular Cloud Complex, Cygnus X appears to host some 26,000 possible young stellar objects, according to an announcement last week.

Moving farther from home, I talked a bit about the new dark matter map that I previously described in a post from Austin. It turns out that analyzing the light from 10 million galaxies call tell you a lot about where dark matter resides, and since dark matter drives the formation of much of the structure in the Universe, that knowledge helps us understand more about the evolution of the cosmos…

The dark matter maps tell one part of the story, but we also rely on studies of the cosmic microwave background to tease out how the Universe has evolved over time. Since 2003, the gold standard of such measurements have come from the Wilkinson Microwave Anisotropy Probe (WMAP). But ESA’s Planck mission recently completed its survey of the cosmic microwave background: the sensor used to make the observations ran out of its coolant a little less than a week ago. It had collected more than two years’ worth of data, however, and the first new high-resolution maps will be released early next year. (Hey! It takes a while to process all that data.)

That’s all for now. Check back for next month’s update! Or come to NightLife on Thursday, 15 February, and check out “Universe Update” live in the Morrison Planetarium.

Ryan Wyatt is the director of the Morrison Planetarium and Science Visualization at the California Academy of Sciences.

Image: SOHO (ESA & NASA)