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.
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.
That analysis was done here: http://norskmeteornettverk.no/... (it's not in English, but google translate does a decent job). He makes a distance estimate based on speed, which itself is based on the assumption it's a falling rock at terminal velocity. But the distance, speed, and time it takes to cross the FOV are related, and if you make a stab at speed you can get distance and vice versa.
Yes, the apparent speed is the biggest argument against it being something packed in the 'chute, I'd think. If the skydiver were still decelerating hard after the parachute opened, the rock could appear to move rapidly, but even then it appears to come from farther away than the parachute. I'm still looking into this, and will have my own thoughts posted tomorrow on my blog.
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 headline as submitted isn't really correct. The planet is not the biggest found; there are several whose mass may be larger, like the exoplanets announced just last week (and this planet has 11 times the mass of Jupiter; we don't know its actual size). The real issue with HD 106906 b is that it is so far out from its parent star, much farther out than planets with that ass should form. Either it formed farther in and got tossed out (which is unlikely) or it formed where it was, which current theories say is difficult; usually objects forming that far out have much higher mass. I explain all this in my own blog post about it.
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.