With stars topping Christmas trees and twinkling lights covering houses, the holiday season is the perfect time to stop and think about the real stars that surround us all year. 2011 was an important year for astronomy, and with the daily advances in our capabilities to explore the universe, 2012 might be even more impressive.
Before 2011 comes to an end, it’s worthwhile to look back on this year’s most important discoveries and what they mean for the future of astronomy. There have been too many discoveries to cover them all, but here’s a look at some of the more interesting (and comprehensible):
This vein of gypsum on Mars could be evidence that water once ran there. | Photo courtesy of NASA/JPL-Caltech/Cornell/ASU
Water on Mars
Was there ever liquid water on Mars? This is a hotly contested question in the popular science world. In December, the mystery was one step closer to being solved: the Opportunity Rover uncovered what Steve Squyres, the lead researcher for the rover, says is the most “bullet-proof evidence” from the rover’s mission thus far.
Previous potential evidence was found in surface particles that could have been blown in from anywhere. This time, the rover found a line of gypsum in the red planet’s bedrock, suggesting the mineral was created there on Mars. Gypsum, a mineral created when water flows through rock, doesn’t require a highly acidic environment like previously found minerals do, suggesting the water on Mars could have been much more gentle than scientists thought.
If the mineral is confirmed to be gypsum, it would be “the single most powerful evidence for liquid water” on the planet. The Opportunity Rover has been traveling years longer than its original 90 day mission, and scientists eagerly wait for the confirmation of the mineral’s origin in hopes of finally knowing if there was once liquid water on Mars.
Giant Alien Worlds
Earlier this month, eighteen new super-massive gas giants were found orbiting stars even bigger than our own Sun. Scientists at the California Institute of Technology have been searching the sky looking for stars more than one and a half times the size of the sun and picking out the ones that wobble, a phenomenon often caused by the pull of orbiting planets. In their search, they found eighteen new Jupiter-sized planets, increasing the number of known planets orbiting supermassive stars by 50%.
According to current theories of planetary formation, planets are the product of small particles in the dusty disk around a newly-formed star. More and more tiny particles clump together until the planet is formed, like how a snowball is made. If this theory is correct, then larger stars with larger disks should result in larger planets—something that this discovery seems t0 support.
As John Johnson from the discovery team at Cal Tech said, scientists are thrilled to “see all these converging lines of evidence pointing toward one class of formation mechanisms.” A better understanding of general planet formation thanks to planets like these can help scientists move towards an understanding of how our own solar system formed. Scientists are puzzled, however, about why these new planets travel in circular orbits, rather than the usually found elliptical ones.
While their discovery was a success for the current theory of planet formation, there are still unresolved questions to be answered before scientists can determine how this and other solar systems were formed.
In February, scientists observed for the first time what they believe is a new planet being born around a young star. While observing the star T Chamaeleontis (T Cha), a star 350 light years away and just seven million years old, scientists noticed a gap in the disk of debris surrounding it. In that gap, it seems that a young planet is being born from the dust clumping together. It is the earliest evidence that has been found of a disk of just dust transforming into a planetary system. Like the discovery of the 18 gas giants, this reinforces the current theory of planetary formation and moves scientists closer to answering how solar systems like our own are born. Astronomers are relieved to fill in the missing pieces of planet formation with evidence like this. It shows that planets are formed, on a grand scale, very early in the life of a star. Future observations will determine what type of planet this is, and how similar T Cha is to our own Sun. Regardless of the outcome, it’ is exciting to see the planetary-formation puzzle pieces coming together.Kepler Program and Discovering New Exoplanets
An artist’s rendition of the potentially habitable exoplanet, Kepler 22b. | Image courtesy of NASA/Ames/JPL-Caltech.
The Kepler Program is possibly one of the most exciting programs in recent history. NASA’s Kepler Space Telescope, launched in March 2009, is on a mission to find Earth-like planets in the habitable area, or “Goldilocks Zone,” of stars they orbit. Before Kepler’s more recent finds, there were only a few known and possibly-habitable exoplanets.
But as of this month, the telescope has found over 2,000 new candidates! First studied in 2009, Gliese 581d was thought to be the first potentially habitable exoplanet. It was recently concluded that the exoplanet could support liquid water, but its 5.6-times-Earth size makes habitability unlikely.
Then, in August of this year, HD 85512b was found and concluded to be another enticing possibility, especially because it is only 36 light years from Earth despite being super-Earth size. Thanks to the Kepler program, the number of known exoplanets is growing rapidly. Of the thousands of potential candidates, 48 seem to be in the habitable zone of the stars they orbit.
The most exciting of these finds is Kepler 22b.
According to NASA scientists, Kepler 22b is “a major milestone on the road to finding Earth’s twin.” The planet’s surface temperature is a comfortable 72 degrees, its 290-day year is similar in length to our own and it is about the same distance from its star as Earth is from the Sun. At 2.4 times the size of Earth, it is possible that Kepler 22b is a little too massive to support life at its surface, but scientists are still hopeful. Until further investigation, scientists can only speculate about what the surface might look like. And at 600 light years away, it is still far beyond our reach. Even though it’s not perfect, the discovery of something that looks so promising is bringing scientists one small step closer to understanding if there’s life anywhere else in the Universe.
In addition to these major discoveries, there are many more that are just as important for the future of astronomy that aren’t mentioned here. Whole books could be written about just the discoveries made by NASA this month, let alone other scientists throughout the year. Here’s a few more of the more interesting ones that are changing the way we perceive our Universe.
Super Massive Black Holes
Astronomers at UC Berkeley have found a black hole that is 9.7 billion times the mass of our Sun and another that is as big, if not bigger. They are unsure how these black holes, far into old age, got so big, and hope to understand more about black hole formation as they continue their research.
The orange spot within the green cloud shows evidence of star birth. | Photo courtesy of NASA, ESA, W. Keel (U. of Alabama) and the Galaxy Zoo Team.
The mystery of the giant odd-looking cloud discovered in 2007 has finally begun to unravel. Named Hanny’s voorwerp (“voorwerp” is Dutch for “object”), this cloud is bigger than the entire Milky Way galaxy and was called “one of the strangest space objects ever seen” by the American Astronomical Society.
In January of this year, when the Hubble Telescope sent back the clearest picture yet, scientists discovered that the cloud isn’t just inactive gas. Rather, the side of the cloud closest to the neighboring galaxy shows evidence of ongoing star formation. The new pictures not only help to solve one of the most recent great mysteries of the Universe; they also allow a rare look into the birth of stars.
The Coldest Star Yet
Scientists at the University of Hawaii have found a small star with surface temperatures of around 206 degrees Fahrenheit (97 °C), much colder than any star seen before. They also have their eyes on another star that might have temperatures as low as 86 degrees Fahrenheit. Both stars are brown dwarfs and are blurring the distinction between stars and planets. As gas-giant planets are found with temperatures much higher than these cool stars, scientists are being pushed to understand just where to draw the line between brown dwarf stars and massive gas-giant planets.
This galaxy gives a good idea of what our own galaxy might look like from the outside. | Photo courtesy of NASA/JPL-Caltech/UCLA.
Milky Way Twin
Scientists have discovered a galaxy 30 million light years away from Earth, NGC 6744, looking quite a bit like our own. The view of this galaxy, says ESO press officer Richard Hook, “is close to the one we could see … if we had the technology to escape the Milky Way.” Although twice the size of the Milky Way, this galaxy gives scientists and casual observers alike an idea of what our galaxy might look like if we could see it from outside.