Asteroids; the ultimate villain.  If they’re big enough (and many are), they are capable of destroying all life on Earth in a single event.  Many doomsday scenarios making their viral way around the Web prominently feature asteroids to play on this fear.  We know it’s happened before, and we know the odds are good it will happen again.

I wrote a post not too long ago called “Chicken Little Was Right” (you can look it over here if you’re interested) which talks about chunks of real estate bombarding Earth.  That’s definitely a concern when talking about asteroids, but today I want to talk about asteroids that aren’t falling to Earth destroying civilization.

Image released to Public Domain - Distribution of asteroids in the inner solar system

An asteroid is a small body orbiting the Sun; smaller than a planet but larger than a meteoroid.  They are closely related to comets, the main difference being asteroids do not have a coma, and comets do.  Comets are believed to come mostly from the Oort Cloud, while asteroids are mostly concentrated further inward; being somewhat rare beyond the Scattered Disc.

NASA/JPL artist's conception of the Dawn Mission probe with Vesta (left) and Ceres (right)

When talking about asteroids, the first thing that comes to mind for most people is the Asteroid Belt.  When I was growing up, it was still common belief that the asteroids where remnants of a planet that once orbited between Mars and Jupiter.  Now, of course, we know there never was a planet in that space; Jupiter became large enough to disrupt the accretion process.  We did get a few good-sized bodies in the Belt:  Ceres,  3 Juno, 4 Vesta, 5 Astraea, 2 Pallas, and 10 Hygiea.  Ceres, in fact, is large enough to be classed as a Dwarf Planet.  The asteroid Ida, while not large enough to be a dwarf planet, is large enough to have her own little moon.  While Ida was the first asteroid found to have a little moon, many more have since been discovered.

NASA/JPL Galileo approach to Ida 02/1996

When asteroids get pulverized into dust, we get to see Zodiacal light.  This eerie, beautiful phenomenon is caused by sunlight reflecting off the dust.

Image: Mila Zinkova - Orionid Meteor Shower showing Zodiacal green and red light at bottom of image

There’s a lot to be said about asteroids, and the more we know about them, the more interesting they become.

And of course, one day an asteroid is going to come crashing into Earth and destroy most (if not all) life on the planet.

Meteor Crater in Arizona - Image PD US Gov