Read the rest of Emily Baldwin's text here: http://www.astronomynow.com/news/n1106/28genesis/Nitrogen has one isotope, N-14, that makes up nearly 100 percent of the nitrogen atoms in the Solar System, but there is also a small contribution of N-15. The Genesis results showed that the Sun and Jupiter have the same nitrogen composition, but that they have slightly more N-14 and around 40 percent less N-15 than the Earth. Genesis scientists speculate that Earth might have received its heavier nitrogen from comets that smashed into the Earth during the Solar System's youth. A sample return mission to a comet would help answer that question.
Similar to nitrogen, nearly 100 percent of oxygen atoms are O-16, but there are also small amounts of isotopes O-17 and O-18. “We found that Earth, the Moon, as well as Martian and other meteorites which are samples of asteroids, have a lower concentration of the O-16 than does the Sun,” says Kevin McKeegan, a Genesis co-investigator from UCLA. The other isotopes’ percentages were slightly lower in the Sun than the Earth. “The implication is that we did not form out of the same solar nebula materials that created the Sun – just how and why remains to be discovered.”
Ann
