The Bad Astronomer writes: Astronomers have found a new asteroid, 2014 OL339, that is a quasi-moon of the Earth. Discovered accidentally earlier this year, the 150-meter asteroid has an orbit that is more elliptical than Earth's, but has a period of almost exactly one year. It isn't bound to Earth like a real moon, but displays apparent motion as if it did, making it one of several known quasi-moons.
Submission Summary: 0 pending, 34 declined, 92 accepted (126 total, 73.02% accepted)
The Bad Astronomer writes: Astronomers have found a 5.4 Earth-mass planet orbiting the star Gliese 15A, a red dwarf in a binary system just 11.7 light years away. Other exoplanets candidates have been found that are closer, but they are as yet unconfirmed. This is more evidence that alien planets are common in the galaxy.
The Bad Astronomer writes: The Mars Reconnaissance Orbiter spotted a new crater on the surface of Mars, and, using before-and-after pictures, the impact date has been nailed down to less than a day — it happened on or about March 27, 2012. The crater is 50 meters or so in size, and surrounded by smaller craters that may have been caused by smaller impacts due to the incoming meteoroid breaking up. Several landslides were spotted in the area as well, possibly due to the shock wave of the impact.
The Bad Astronomer writes: Astronomers have just announced that the exoplanet Beta Pic b — a 10-Jupiter-mass world 60 light years away -— rotates in about 8 hours. Using a high-resolution spectrometer and exploiting the Doppler shift of light seen as the planet spins, they measured its rotation velocity as 28,000 mph. Making reasonable assumptions about the planet's size, that gives the length of its day. This is the first time such a measurement has been achieved for an exoplanet.
The Bad Astronomer writes: Using data from the orbiting WISE and Spitzer infrared space telescopes, an astronomer has discovered a brown dwarf that is just 7.2 light years away, making it the seventh closest known interstellar object to the Sun. Not only that, it's cold ; its temperature is likely 240-260 Kelvin, well below the freezing point of water. It's literally as cold as ice.
The Bad Astronomer writes: Astronomers have announced the discovery of Kepler-186f, a very nearly Earth-sized planet in its star's habitable zone. The planet is the fifth in a system of five orbiting a red dwarf star 500 light years away, and is located in the region where liquid water could exist on its surface. It's not know if this planet is Earth-like — that is, with water and air and the potential for life — but it's the closest we've yet seen where one could be like our own planet.
The Bad Astronomer writes: The viral video showing what looked like a meteorite falling past a skydiver made quite a splash, with many people assuming it was true. However, further analysis shows that it's also perfectly consistent with being a small (1-3 cm) rock that fell out of the parachute itself, which is a far more likely explanation.
The Bad Astronomer writes: A new and potentially bright supernova was just discovered in the nearby galaxy M82. This is a Type Ia supernova, the catastrophic explosion of a white dwarf. It appears to be on the rise, and may have been caught as much as two weeks before peak brightness. It's currently already brighter than magnitude 12, and may get to mag 8, easy to see in small telescopes. The galaxy is less than 12 million light years away, so this may become one of the best-studied supernovae in recent times. Type Ia supernovae are used to measure dark energy, so seeing one nearby is a huge boon to astronomy.
The Bad Astronomer writes: The Gemini Planet Imager is a camera that is designed to take direct photos of exoplanets, alien worlds orbiting other stars. In a test run last November it spotted the exoplanet Beta Pictoris b, a dusty ring around a nearby star, and even snapped a portrait of Jupiter's moon Europa. Up to now, only about a dozen exoplanets have been directly imaged; GPI is expected to find dozens more in the next few years.
The Bad Astronomer writes: On December 24, 1968, the Apollo 8 astronauts saw the Earth rising over the limb of the Moon. The photo they took of this moment — dubbed Earthrise —has become an icon of our need to explore, and to protect our home world. NASA has just released a video explaining how the astronauts were able to capture this unique moment, which included a dash of both coincidence and fast teamwork.
The Bad Astronomer writes: Planets orbiting other stars are usually found indirectly (by blocking their stars' light or inducing a Doppler shift in the light as they orbit, for example), but direct images of exoplanets are extremely rare. However, using the 10-meter Keck telescope in Hawaii, astronomers have taken photographs of three nearby exoplanets, all young, massive, and hot. One may be massive enough to count as a brown dwarf, but the other two are more likely in the planet-mass range. All three are very far from their stars, which means they may have formed differently than the planets in our solar system.
The Bad Astronomer writes: Using data from the Feb. 15, 2013 asteroid impact over Russia, scientists have determined that we may be hit by objects in this size range (10 — 50 meters across) more often than we previously thought, something like once every 20 years. They also found the Chelyabinsk asteroid was likely a single rock about 19 meters (60 feet) across, had a mass of 12,000 tons, and was criss-crossed with internal fractures which aided in its breakup as it rammed through the Earth's atmosphere.
The Bad Astronomer writes: A new study, looking at over 40,000 stars viewed by the Kepler spacecraft, indicates that 22% of stars like the Sun should have Earth-like planets orbiting them — planets that are similar in size to our home world and with a surface temperature hospitable for liquid water. There are some caveats (they don't include atmospheric issues like the greenhouse effect, which may reduce the overall number, or at cooler stars where there may be many more such planets) but their numbers indicate there could be several billion planets similar to Earth in the Milky Way alone.
The Bad Astronomer writes: Last week, astronomers discovered 2013 TV135, a 400-meter wide asteroid that will swing by the Earth in 2032. The odds of an impact at that time are incredibly low — in fact, the chance it will glide safely past us is 99.99998%! But that hasn't stopped some venues from playing up the apocalypse angle. Bottom line: we do not have a good orbit for this rock yet, and as observations get better the chance of an impact will certainly drop. We can breathe easy over this particular asteroid.
The Bad Astronomer writes: On Oct. 10, 2013, the Cassini spacecraft took a series of wide-angle pictures of Saturn from well above the plane of the rings. Croatian software developer and amateur astronomical image processor Gordan Ugarkovic assembled them into a stunning mosaic (mirrored on Flickr), showing the planet from a high angle not usually seen. There's a lot to see in this image, including the rings (and the gaps therein), moons, and the planet itself, including the remnants of a monstrous northern hemisphere storm that kicked off in 2010. It's truly wondrous.