A digital orrery. It has two settings: Earth centered (Tychonian), and Sun centered (Copernican). You can select any time to see the positions of the planets, by clicking on the outer ring at the zodiac:
The Kepler spacecraft has found a strange solar system, packed with 6 planets, very close together. Five of these objects orbit their sun in a space equivalent to that between Mercury and the Sun:
A remarkable planetary system discovered by NASA’s Kepler mission has six planets around a Sun-like star, including five small planets in tightly packed orbits. Astronomers at the University of California, Santa Cruz, and their coauthors analyzed the orbital dynamics of the system, determined the sizes and masses of the planets, and figured out their likely compositions — all based on Kepler’s measurements of the changing brightness of the host star (called Kepler-11) as the planets passed in front of it…
…The five inner planets in the Kepler-11 system range in size from 2.3 to 13.5 times the mass of the Earth. Their orbital periods are all less than 50 days, so they orbit within a region that would fit inside the orbit of Mercury in our solar system. The sixth planet is larger and farther out, with an orbital period of 118 days and an undetermined mass.
An exquisite re-use of an existing spacecraft, and a second chance to see the results of the first man-made deep space collision:
NASA’s Deep Impact mission pounded a comet in 2005, but failed to see the resulting crater. Now, scientists will get a second chance to glimpse the damage when a second spacecraft flies by the comet on 15 February.
In an unprecedented experiment, NASA smashed a 372-kilogram impactor into Comet Tempel 1 on 4 July 2005 as part of its Deep Impact mission.
A flyby spacecraft recorded images of the impact from a safe distance, but the cloud of impact debris and a flawed camera made it impossible to see the crater itself. Studying the crater could have revealed more about the interior composition and structure of comets.
Now, another spacecraft is about to make its own fly-by of the comet, offering a second chance to image the structure.
Called Stardust, the spacecraft collected material from Comet Wild 2 in 2004 and sent it in a capsule back to Earth, where scientists have been studying it ever since.
It would be nice to live to see this: should Betelgeuse, one of the stars in much loved constellation of Orion explode (as astronomers expect it to do, soon), it’ll be very bright. As bright as the full moon, maybe brighter. Probably visible during daytime! In spite of much online noise, it’s unlikely to kill life on Earth – that Honour shall belong to the Mucoid Invader Fleet of #21343314390-K. They’re not due to arrive for another 23 years. The ensuing horror will make you curse the day of your conception. Until then:
We will see a bright light, a flash, which will last for years. But even at its strongest, it will be about as bright as the Moon – not anywhere near as bright as the Sun. There are several types of supernovas, and we know that this one will be a type two.
We also know what its maximum luminosity will be; we have seen similar ones in other galaxies. It will be bright enough to light up the night sky as much as the Moon does.
As for gamma rays or high-energy particles, there’s no reason to worry about them. We have nothing to be concerned about before the shock wave reaches the Earth, and this won’t happen for a very long time. It will expand at a speed well below the speed of light. If it takes the speed of light 640 year to reach the Earth, something travelling a hundred times slower will take a very long time to reach us.
Lovely, and just a little creepy: Greenland’s Moulins
A moulin is a hole in a glacier that funnels meltwater from the surface to the bedrock beneath. This flow of water has importance consequences for the speed at which the glacier moves.
Warmer summers may paradoxically slow down the speed of glaciers flowing towards the sea, suggests new research. This investigation, using data from ESA’s oldest environmental satellite, has important implications for future estimates of sea-level rise.