Asteroids and Comets

All the Little Things in the Solar System, and the Things They Can Do to Earth

Is there an asteroid or comet out there that poses a risk to life on Earth? The answer is certainly "yes," but we don't yet know where the next major impactor will come from or when it will crash. The best way to reduce this uncertainty is to search the skies for these crumbs of the solar system. The Planetary Society has a long history of supporting amateur and underfunded professional astronomers in their efforts to discover and track potentially hazardous near-Earth objects. This is useful not only for planetary defense, but also for learning about the solar system's origin and evolution.

A fortuitous byproduct of our increasing ability to detect fainter objects is that, for the first time, we now stand a chance of discovering smaller, five- to ten-meter-sized rocks while they are still in space before they burn up in our atmosphere and scatter meteorites along the ground. We are now beginning to link meteorites that we can study in our labs with the data on orbits and compositions that we amass with astronomical observations. Every meteorite, every tiny asteroid has a story, and we can combine these stories together to answer fundamental questions about how the solar system formed and evolved. What were the ingredients that made Earth and the other planets? How are those constituents different now? How have asteroid and comet impacts shaped the origin and evolution of life on Earth (and, potentially, on other planets)? Can asteroids serve as stepping-stones for human travel to farther destinations?

Blogs About Asteroids, Comets, and the Impact Threat

Dione, Mimas, Titan, Tethys, Rhea, Enceladus, Hyperion, and Iapetus, from Cassini science data, to a common scale and from similar phase angles, montage by Emily Lakdawalla

What Saturn's moons can tell us about comets (Notes from LPSC 2012)

Posted by Emily Lakdawalla on 2012/04/03 05:20 CDT

My notes on a two-part presentation by collaborators Jim Richardson and David Minton about the sizes of things in the Kuiper belt, a story they told by looking at Saturn's moons. How does that work? What connects Saturn's moons to the Kuiper belt is craters.

La Sagra Observatory discovers very near-Earth asteroid 2012 DA14

Posted by Jaime Nomen on 2012/03/27 05:20 CDT | 3 comments

With a new CCD camera configured to shoot rapid, short exposures bought with a Planetary Society Shoemaker NEO Grant we caught near-Earth asteroid 2012 DA14.

New "Snapshot From Space": Defending Our Planet

Posted by Mat Kaplan on 2012/03/06 10:18 CST

A new installment of our "Snapshots" video series examines the threat posed by asteroids on collision courses with our home planet. Emily Lakdawalla explains why it's so important to find, understand and learn to deflect these potential civilization enders.

Items 58 - 60 of 97

Eros' northern hemisphere as seen by the NEAR spacecraft on February 29, 2000. The view is a mosaic of six images.

Asteroids and Comets Visited by Spacecraft

A comparison of all the asteroids and comets ever visited by spacecraft, up to date as of November 10 (when Deep Impact flew past Hartley 2). Vesta is not included.

During the first few hundred million years after oceans appeared on the young Earth, life may have repeatedly begun only to be erased in planetwide sterilization events as very large planetoids were colliding with the larger worlds.

Sizing Up the Threat from Near-Earth Objects (NEOs)

Scientifically, it is useful to divide the impact hazard into two types of events: those with local consequences and those with global consequences. Global events, while much less likely, actually pose a greater risk.

The Torino Scale

The Torino scale is a color-coded advisory system that enables near-Earth object (NEO) researchers to place objects within a potential threat range from zero -- where there is virtually no chance of collision, to 10 -- where global catastrophe is certain.