How many words can you create out of atmosphere?

Well, I got 19 Words:at, a, most, here, sphere, sat, hat, mere, some, mat, math, pat, rat, pot, hot, rot, roam, the, and as. There may be more, but I couldn't think of any more.

atom, there, are, sear, rest, stamp, post, roast, pet, met....

tear... Is phat a real Word? if not, then I think that's all.