Visit the USGS Home Page Go to the Astrogeology Research Program Home Page USGS Astrogeology Research Program

Happy 4th of July from USGS Astrogeology!

Friday, June 30, 2006

Fireworks
Happy Independence Day!

Somebody Define Planet, Please

Tuesday, June 20, 2006

2003 UB313
Artist concept of 2003 UB313
(also known as the "10th" planet)
Credit: Robert Hurt (IPAC)
256X192

The International Astronomical Union (IAU) will be meeting this August to hammer out the final definition of the word "planet." If approved, the definition will be announced in September.

Webster defines the word planet as: any of the seven celestial bodies sun, moon, Venus, Jupiter, Mars, Mercury, and Saturn that in ancient belief have motions of their own among the fixed stars b (1) : any of the large bodies that revolve around the sun in the solar system (2) : a similar body associated with another star.

So one might ask, what's the big deal? Apparently it's UB313, an object roughly the size of Pluto that orbits the Sun beyond Neptune. The object's discoverer, Mike Brown of Caltech, has argued it should be called a planet. Some astronomers say if UB313 is a planet, then several similar bodies should gain the same status. The number of planets in our solar system could ultimately climb into the thousands as technology improves.

What will the definition be? Will they scratch Pluto from being a planet? What qualifiers will they use to rewrite this definiton? Will they look at mass? Some have wondered if they in fact would include orbit characteristics and formation scenarios? I suppose we won't know until the new committee that includes historians and educators, make their recommendation to the IAU in September. Mark your calenders.

A Baby Crater is Born

Tuesday, June 13, 2006

MoonOn May 2, 2006, a baby crater was born on the Moon. NASA says its about 14 meters wide, 3 meters deep and precisely one month, eleven days old. What a baby!

NASA astronomers watched a meteoroid hit the Moon's Sea of Clouds (Mare Nubium) with 17 billion joules of kinetic energy.

Bill Cooke, the head of NASA's Meteoroid Environment Office in Huntsville, Alabama said that the impact created a bright fireball, which was video-recorded using a 10-inch telescope. Stuff hits the Moon all the time," said Cooke--but this is the best-ever recording of an explosion in progress."

Show me the impact and tell me the full story!