5. DAF39- WHAT IS "APITCHEY DGEHNOM"- IS IT REAL FIRE?
Your question is very interesting. TOSFOS in Chulin (8a, DH b'Chamei Teveriah), regarding a Nega which appears on a wound caused by a heat source other than fire, says that perhaps Chamei Teveryah is different than fire in that it is fire that is created "b'Yidei Shamayim," by Divine hands, so to speak. The RAMBAM, explaining the Mishnah in Negaim, says that the heat source is similar to sulfur pits and does not come from fire. If so, it need not be fire "out of H-ll."
The Gemara in Pesachim (54a) says that the fire we use was created on the first Motza'ei Shabbos after Creation, and the fire of Gehenom was created on the second day of Creation (several days earlier). This clearly implies that there is a "fire" raging in Gehenom, which is a completely different entity from the one we know of.
Moshe
Rav Aharon Soloveitchik in his book interprets this Gemara as meaning heat from the interior of the earth. The Gemara uses the terminology of Gehinnon because they had no other way of expressing it.
He says that anyone who interprets the Gemara literally just allows others to make fun of the Chazal.
Eli Turkel