Now that 2012 has really and truly been put to bed, let’s look at the year that was in space exploration and astronomy.
My choice for #1 was a no-brainer: not only is spectacular science already rolling in, but the top space event of the year—the August landing of the Curiosity rover on Mars—also crossed over into mainstream news coverage in a big way. Even Esquire took notice of Curiosity in its recent “Americans of the Year” issue. For me personally, it was a highlight: after staying up all night to cover the rover’s “seven minutes of terror” landing, I made a morning appearance on the Weather Channel to talk with Al Roker and his colleagues about Curiosity and some of the ways that the rover will improve weather forecasting on Mars. (Unfortunately the links to those segments appear to have expired.)
Narrowing down a year’s worth of news to fill the other nine slots was surprisingly tough. What did I miss? Let me know in the comments. And now, without further ado…
10. A meteorite boom in gold country
In April a daytime fireball over Northern California heralded a meteorite fall near Sutter’s Mill, where the California Gold Rush began in 1848. Doppler radar data and eyewitness documentation led researchers to conclude that the Sutter’s Mill meteorite made an unprecedented high-speed entry; the data also guided searchers to dozens of fragments on the ground, some of which were recovered within days. Analysis of those samples, mostly unsullied by rainfall and other terrestrial weathering processes, has provided hints that a rare class of meteorite called carbonaceous chondrites may be more complex in composition than had been thought. Coincidentally, Northern Californians were treated to another brilliant fireball in October.
The space shuttle program officially ended in 2011, but 2012 was the year that the shuttles made their way to their final homes. With flyovers of Washington, D.C., New York City, San Francisco, Houston and Los Angeles, among other locales, countless individuals got their first—and last—close look at a space shuttle in flight, albeit at low altitude atop a modified 747.
Scorching, sun-baked Mercury has long been neglected as a destination for planetary exploration, having had only one scanty series of flybys in 1974 and 1975. But after NASA finally sent a dedicated orbiting spacecraft there in 2011, surprising science started pouring in. This year we learned that Mercury’s polar craters appear laden with water ice, despite the searing temperatures of roughly 400 degrees Celsius at lower latitudes due to the innermost planet’s proximity to the sun. (Mercury orbits at only 40 percent the Earth-sun distance.)
7. Planetary science meets the budgetary ax
In February NASA and the White House announced new budgets for the space agency, and planetary scientists promptly reeled. The new numbers included a 20 percent cut to planetary science programs and canned two Mars missions that had been planned with the European Space Agency in 2016 and 2018. The move caused concern that planetary exploration missions would be unable to address key science questions in the years to come. For instance, the joint ESA missions would have taken steps toward the future return of Martian rock and soil samples to Earth. (NASA later announced plans for a different Mars rover, to launch in 2020, but that mission may not include a sample-return aspect.)
Two of the most famous astronauts in spaceflight history passed away in 2012. Sally Ride, the first American woman in space, who flew on two space shuttle missions, died of cancer in July at age 61. A month later Neil Armstrong, the first man on the moon during the Apollo era, passed away at age 82 due to complications from cardiovascular surgery.
5. Voyager 1: Are we there yet?
It was a big year for the Voyager 1 spacecraft. For starters, NASA celebrated the 35th anniversary of the launch of the pioneering probe (not to be confused with the Pioneer probes) and its twin Voyager 2, also launched in 1977. But more importantly the spacecraft delivered a series of new findings as it draws near the outer boundary of the heliosphere (a giant bubble in space inflated by plasma from the sun) and the edge of interstellar space. Mission scientists announced that Voyager 1 had not yet left the heliosphere, then noted that puzzling new data were inconclusive on that front, and finally determined that Voyager remained inside but had discovered a new facet of the solar system.
Researchers around the globe made great strides in identifying many of the most distant celestial objects ever recorded. Researchers in Japan used the Subaru telescope to identify a galaxy so far away that its light has traveled 13 billion years to reach us—a remarkable fact, given that the universe is 13.7 billion years old. Though more distant objects were already known, the Japanese group was able to make a rare precision measurement of the galaxy’s distance by taking a spectrum of the galaxy’s light. Other scientists used the orbiting Hubble Space Telescope to spot an even more distant galaxy, which had been magnified by the effects of gravitational lensing, in which a massive object bends light rays as they propagate across the universe. Shortly thereafter another group, also tapping into Hubble’s observing power, located not one but seven galaxies in the early universe, one of which may well be the most remote known object, having emitted its light some 13.3 billion years ago.
3. SpaceX special delivery
Commercial spaceflight companies are expected to fill the void left by the decommissioned space shuttles, but until 2012 few had conclusively demonstrated their readiness for service. SpaceX passed an important milestone in May when its Dragon cargo capsule returned safely from a resupply trip to the International Space Station. The mission marked the first time that a private operator had docked at the station and kicked off a series of SpaceX cargo runs under contract with NASA.
2. A new interstellar neighbor
Exoplanet findings are commonplace these days, with 854 so far known by one count, but Alpha Centauri B b was no ordinary discovery. Just 4.3 light-years away, the presumably rocky exoplanet is the nearest known world to our own solar system. In the words of one leading researcher, “You can spit a watermelon seed to Alpha Centauri.” Its presence offers new hope that Alpha Centauri B, one of the stars nearest the sun, might host additional exoplanets, perhaps even worlds with potentially habitable climates. Such nearby planets, if favorably aligned, would make promising subjects for studies of atmospheric composition.
It took an exquisitely choreographed sequence of heat shield, parachute, retrorockets and something NASA calls a “sky crane” to pull off an unprecedented feat—plopping a supremely sensitive mobile laboratory the size of a small car onto the surface of another planet. Gently. But the landing of the Curiosity rover went off without a hitch, and the six-wheeled robot is now cruising Mars in pursuit of evidence that the Red Planet was once hospitable to extraterrestrial microbes. The mission, still in its early phases, is off to such a promising start that NASA has vowed to send a similar rover to Mars in 2020.
Photo credits: NASA/Matt Hedges (shuttle); NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington (Mercury); NASA (Armstrong); NASA, ESA, R. Ellis (Caltech) and the UDF 2012 Team (Hubble image); NASA/JPL-Caltech/MSSS (Curiosity)