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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

Rosetta NAVCAM's Shades of Grey

Posted by Claudia Mignone on 2014/10/27 09:51 CDT | 1 comment

What do “light” and “dark” mean for an object like Comet 67P/C-G? Here are some details on how Rosetta's NAVCAM images are taken and displayed to make a wide range of surface features possible.

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Herschel observations of Comet Siding Spring initiated by an amateur astronomer

Posted by Peter Mattisson on 2014/10/22 11:26 CDT | 4 comments

The European satellite Herschel acquired images of Comet Siding Spring before its death in 2013 — thanks to an observing proposal from an amateur astronomer!

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Status update: All Mars missions fine after Siding Spring flyby

Posted by Emily Lakdawalla on 2014/10/20 12:07 CDT | 2 comments

All seven Mars spacecraft are doing perfectly fine after comet Siding Spring's close encounter with Mars.

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Asteroids, Comets, and the Threat

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.

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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.

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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.

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Space in Images

Pretty pictures and
awe-inspiring science.

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