For the first time, NASA’s Hubble Space Telescope has seen distinctly the “tenth planet,” currently nicknamed “Xena,” and found that it’s only slightly larger than Pluto.

Though previous ground-based observations suggested that Xena’s diameter was about 30 percent greater than Pluto, Hubble observations taken Dec. 9 and 10, 2005, showed Xena’s diameter as 1,490 miles (with an uncertainty of 60 miles).

Pluto’s diameter, as measured by Hubble, is 1,422 miles.

credit: NASA

1. Eward N. Says:
   January 4th, 2008 at 12:07 pm

   someone says that the 10th planet is bigger than jupiter, What’s the truth?