The air force revealed this information, which is usually kept secret, because it wants to make the case that it makes more sense to cut production of the F-35 (which cost $30-50 million each), so that more F-22s (that cost over $100 million each) can be bought. Most of the air force generals are former fighter pilots, and the F-22 is a much hotter fighter than the F-35 (which is basically a fighter-bomber, with emphasis on the latter function.) This is causing an international uproar, because of the many foreign countries that are buying the F-35. Some of these countries have contributed money for the development of the F-35. The F-22 will not be exported, because it uses so much top secret technology.
The U.S. Air Force, in it's effort to get money to build more F-22s, has revealed just how "stealthy" the F-22 is. It's RCS (Radar Cross Section) is the equivalent, for a radar, to a metal marble. The less stealthy (and much cheaper) F-35, is equal to a metal golf ball. The F-35 stealthiness is a bit better than the B-2 bomber, which, in turn, was twice as good as that on the even older F-117. Much older aircraft, like the B-52, have a huge RCS, which makes them very easy to spot on radar. But with a smaller RCS, it's more likely that the aircraft won't be detected at all.