It’s ironic that in an era of ever-shrinking science budgets, high-flying observatories such as Hubble and the Chandra X-Ray Observatory are producing a wealth of data. And while no new interplanetary spacecraft left the Earth in 2012, several previously dispatched spacecraft such as the Curiosity rover on Mars and the Dawn and Messenger missions made headlines exploring worlds in our solar system. These observatories and spacecraft — along with the scientists and technicians monitoring them — made many exciting discoveries in 2012, expanding our knowledge of distant galaxies, exoplanets and the universe in general. Following, in no particular order, are 10 of the most exciting astronomical discoveries in 2012.
10. Scientists Find “Super Earth” in a Habitable Zone
Astronomers announced the discovery in 2012 of HD 40307 g, a planet 7 times Earth’s mass orbiting in its host star’s habitable zone, what astronomers commonly call the Goldilocks Zone — because it’s supposedly “just right” for life as we know it to exist. This is the zone within which surface water under atmospheric pressure would remain liquid, as it does here on Earth. HD 40307 g was identified by scientists at the European Southern Observatories’ HARPS (High Accuracy Radial velocity Planet Searcher) project, which looks for signs of the planet tugging on its host star.
9. Astronomers Spot Exoplanet in Alpha Centauri
In recent years, astronomers have discovered almost 800 exoplanets, or planets outside our solar system. While each one of these has been exciting, scientists were especially thrilled in 2012 to discover an Earth-sized planet in the closest star system to our own. The exoplanet is in Alpha Centauri, a three-star system that is 4.3 light years distant. Designated Alpha Centauri Bb, the planet circles its star in a tight 3.24-day orbit. However, it is far too hot to support life. Alpha Centauri is visible in the southern sky in the constellation Centaurus.
8. Scientists Discover Farthest Known Galaxy
The Hubble Space Telescope returned yet another first this year with the discovery of MACS0647-JD, a galaxy 13.3 billion light-years from Earth. It’s the most distant galaxy yet observed — a title it may hold for only a few months, given the pace of such discoveries. When we look back through intergalactic distances in space, we’re also looking back in time; we see MACS0647-JD as it appeared when the universe was only 420 million years old. The galaxy was identified via a gravitational lens, when a fortuitous alignment of a foreground galaxy bends and focuses the light of a more distant object.
7. Scientists Spy Rogue Alien Planet
In early November, astronomers announced the discovery of CFBDSIR2149, a “rogue planet” about 100 light years distant. Located in the constellation Doradus, there’s some speculation that rogue, wandering planets may be more prevalent in the galaxy than those gravitationally bound to stars. Astronomers doing a survey of the AB Doradus star cluster discovered CFBDSIR2149. Although it doesn’t shine by reflected light, it does glow faintly in the infrared. CFBDSIR2149 is estimated to be about 4 to 7 times the mass of Jupiter; the higher range (or a new estimation of distance) may put it approaching brown dwarf versus planetary status.
6. New Ideas Emerge About Type 1A Supernovae
Turns out, we may not know as much about supernovae as we thought. A 2012 paper by astronomer J. Craig Wheeler cites both current models for formation of Type 1A supernovae as deficient in terms of the observed data. Current thinking is that a Type 1A supernova occurs when either: A) A degenerate white dwarf star absorbs material from a parent star and explodes; or B) Two white dwarf stars collide and merge. Wheeler proposes a “white widow model,” a twist on the single degenerate model where a white dwarf consumes an M-dwarf star. This would explain a baffling mystery; why stellar remnants of Type 1A supernova are often not observed.
5. Mars Rover Offers Glimpse of Earth’s Neighbor
The Mars Curiosity rover landed in Gale Crater in early August 2012 and has already made some amazing discoveries on the Red Planet. Primary among these is evidence for flowing water on Mars, as seen by telltale signs of water erosion. Curiosity has also already weighed in on the “Martian methane” issue, finding a paucity of the gas in the rarified atmosphere. The rover has also measured the radiation environment at the surface of Mars. Curiosity has a primary mission of one Martian year (about twice that of Earth’s) and may well last much longer than that with its plutonium power supply. As a bonus, the social media and public “buzz” surrounding the Curiosity mission shows it has captured the public’s imagination more than most recent space endeavors.
4. NASA Takes Closer Look at a Giant Asteroid
NASA’s Dawn spacecraft orbited the giant asteroid Vesta from
mid-2011 until early September 2012 and made some amazing discoveries. The spacecraft mapped the tiny worldlet and spied the existence of hydrated minerals on its surface. Studying asteroids is of particular interest because they are examples of the primordial solar system. Dawn is now headed for the asteroid Ceres, to arrive in orbit in 2015.
3. Satellite Probes Edge of the Solar System
Until recent years, much of what we knew about the boundary of our solar system came from theory, not observation. That has all changed since the 2008 launch of NASA’s IBEX (Interstellar Boundary EXplorer). The satellite is mapping the heliopause, which marks the boundary of the solar system, the point far beyond the orbit of Pluto at which the pressure of the solar wind gives way to the interstellar medium. One surprising discovery revealed by IBEX in 2012 is the apparent absence of a “bow shock” as the bubble around our solar system pushes through the void ahead. Scientists have theorized since the 1980s that our solar system caused this type of bow shock, much as a supersonic jet creates a sonic boom. Look for more exciting upcoming discoveries about the boundary of our solar system not just from IBEX but from the twin Voyager spacecraft; launched in the 1970s, those probes are now escaping the solar system.
2. Astronomy Team Peers into Heart of a Black Hole
Like other large galaxies, galaxy M87 features a massive black hole at its center. M87’s black hole is the equivalent of more than 6 billion suns and shoots out a 5,000-light-year-long stream of ionized material. In September 2012 a team at the Event Horizon Telescope project announced it had used four separate radio telescopes to trace that stream all the way to the black hole itself. This detection (apart from the amazing physics involved) will serve as a fine examination of how things occur under extreme relativistic situations.
1. Scientists Find Massive, Prolific Galaxy Cluster
In August 2012, NASA scientists announced an amazing find from the Chandra X-Ray Observatory. The galaxies in the Phoenix Cluster 5.7 light years distant were measured to be producing stars at a rate of more than 700 new stars a year, more than five times the fastest rate previously recorded. Our own galaxy produces new stars at a paltry rate of about one to two per year. First detected by the South Pole Telescope, the Phoenix Cluster may be more massive than any other cluster discovered to date.
One More: Scientists Finally Detect Elusive Higgs Boson
While not exactly astronomy, the announcement of the discovery of the Higgs Boson as detected by the Large Hadron Collider at CERN has implications for our understanding of how the universe operates. The Higgs was the last of the particles predicted by the Standard Model of physics; while the strong nuclear force gives baryonic matter its mass, the Higgs field interaction applies mass to bosons and electrons, which are essential to chemical bonding. This in turn ties the Higgs in with some of the big questions in modern astrophysics that also deal with the mass of the universe, namely dark matter, dark energy, and the cosmological constant. Perhaps what would’ve been an even more stunning discovery would’ve been if the Higgs hadn’t been observed at the predicted energies, turning the Standard Model on its head.