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
A huge amount of effort goes into deciding where to try to collect a sample on Bennu. There are roughly nine months to survey, map and model the asteroid to help make this decision.
Having found a color photo of the comet, I finally added Churyumov-Gerasimenko to my scale comparison of comets and asteroids visited by spacecraft.
Dawn has successfully entered orbit at Ceres, becoming the first mission to orbit a dwarf planet and the first to orbit two different bodies beyond Earth. I also have updates on Curiosity, Rosetta, Mars Express, Hayabusa 2, the Chang'e program, InSIGHT, and OSIRIS-REx.
Asteroids, Comets, and the Threat
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 excitement is building! LightSail is counting down to our test launch, set for May 20—and you’re invited.