Tom Hanks zoomed just 151 million miles from Earth Monday and Meg Ryan will make a pass at us from 191 million miles later this month. How did these celebrities travel so far from Earth without a single mention in the tabloids? Well, they’re living second lives as asteroids of course!
12818 Tomhanks, the 12,818th asteroid to have its orbit determined and name assigned, was discovered on April 13, 1996 by the Spacewatch program at Kitt Peak in Arizona and named after the famous actor for his role in the movie Apollo 13. 8353 Megryan was picked up earlier on April 3, 1989 by E. W. Elst at the European Southern Observatory. Both are small main belt asteroids orbiting between Mars and Jupiter. They’re dim at just 17th and 18th magnitude respectively, so few of us will ever view them in a telescope. Guess we’ll just have to see a movie instead.
The name a newly discovered asteroid receives comes only at the end of a long process that can carry into years. Assuming it’s a unique object and not a re-discovery of an older asteroid, it first receives a temporary designation based on the year and half-month of its discovery, ie. 2011 MD. When the asteroid has been observed long enough that its position can be predicted well into the future, it then gets a permanent number like 12818. At that point, the discoverer is asked to suggest a name. As of September 2011 there are 297,233 numbered minor planets out of the millions that must be out there; only some 16,000 of them have been given both numbers and names.
A special committee within the International Astronomical Union assigns both numbers and names. Naturally there are naming guidelines:
1. 16 characters or less in length
2. preferably one word
3. pronounceable in some language
5. not too similar to an existing asteroid or planetary moon name
And ix-nay on the names of individuals or events known for political or military activities until 100 years after the event or death of the person. And no commercial names either. Sadly, pet names are discouraged.
Their discoverers must have admired the actors to honor them with an asteroid. Many gods, goddesses, scientists, artists, musicians and hard-working amateur astronomers have also been given a touch of immortality with an asteroid name. I’ll leave you with words of wisdom from 20th century American novelist Kurt Vonnegut (asteroid 25399 Vonnegut), whose every book I devoured back in high school: Laughter and tears are both responses to frustration and exhaustion. I myself prefer to laugh, since there is less cleaning up to do afterward.”
Just kidding. I’m not going to leave just yet. Not without sharing this family portrait of five of Saturn’s moons that was recently released by the Cassini probe imaging team. If you like that, take a minute to fly by the planet in the short video below created using nothing but real images taken by the Cassini spacecraft. My favorite segment is crossing through the planet’s ring plane in the final, hi-res clip. Awesome!