Asteroids and comets come in all shapes and sizes—from small pebbles, to larger SUV-sized fragments, to massive asteroids like Ceres, which has a diameter of about 621 miles. Much of the asteroid material that crosses paths with the Earth burns up when it enters the atmosphere. About once every 100 years, though, a fairly large asteroid strikes the Earth.
Russia's proposal for an Armageddon-style mission to deflect the space rock Apophis seemed bold, but it's not the only one fretting about a catastrophic impact on Earth. The U.S. National Research Council (NRC) released a new report that calls for an international asteroid defense agency that can organize a proper mission to counter possible asteroid threats, New Scientist reports.
The harvest moon--which came a couple weeks late this year, on Oct. 4--has long allowed farmers to gather their crops late into the night, using moonlight as a beacon.
Someday, the moon might yield a harvest of its own, thanks to a natural supply of water. A NASA probe is set to crash into the moon this week in search of that potential bounty. Here's how you can watch it from here on Earth.