Pluto's Moon Gives Up Secrets

This Week In Science writes "When Pluto's moon, Charon, occulted a distant star on July 11, 2005 two groups of astronomers were there to witness the fleeting moment. Based on what they saw, the scientists were able to determine that Charon has very little atmosphere, has a radius of 605 km, and is about 1.7 times denser than water. The density calculation implies that Pluto and Charon were once two separate proto-planets that because of a chance encounter are now bound by gravity."

Comments

Wait a second

[Lars T.]

From the article:

The team also found that the density of any atmosphere on the moon must be less than a millionth of that of the Earth. This argues against the theory that Pluto and Charon were formed by the cooling and condensing of the gas and dust known as the solar nebula. Instead, Charon was likely created in a celestial collision between an object and a proto-Pluto.

"Our observations show that there is no substantial atmosphere on Charon, which is consistent with an impact formation scenario," Gulbis said. Similar theories exist about the formation of the Earth-moon system.

That's not the same as "the density calculation implies that Pluto and Charon were once two separate proto-planets that because of a chance encounter are now bound by gravity".

Re:double double toil and trouble

[Bootle]

Well, I was wrong to point the finger so hastily!

Occultation

Might still be the stupidest word I've encountered in a LONG time!