24O has a half life of 65ms, so "24O isn't especially stable. If you look at that table, 23O has a half life of 82 ms, 22O is 2.25 s, and the isotopes gradually get more stable as you approach the stable 16-17-18 isotopes. If it were more stable than 23O, I would agree that it would be surprising, but that's not the case.
In fact, if you look at what they did and read the abstract for the actual paper, the claimed novelty here isn't creating 24O (as others have done so before) or about how stable it is, but rather that they came up with a new technique to characterize it. The article's title is misleading." Said chaos386 on reddit<p><a href="http://www.reddit.com/r/science/comments/14hz9v/oxygen_nucleus_with_twice_as_many_neutrons_as/c7dak0v" rel="nofollow">http://www.reddit.com/r/science/comments/14hz9v/oxygen_nucle...</a>