Or maybe Tom H-Bombadil?

The One Bomb

You zoggin' called?

Will middle earth be able to understand the concept of radiation? Is mordor now an untraversable land? Will they still be able to throw the ring into the mountain?

Hell I think nuking Mordor may be the biggest boon Sauron can get

Unless it just happens to destroy the One Ring along with it?

Which if the Ring were in the Shire and the bomb dropped onto Mordor seems unlikely, but just imagine Frodo and Sam having walked all the way up the mountain and right there at that moment the bomb drops...

What horrific irony that would be.

Could just destroy the ring in a fusion reactor.

Just airburst the nuke, standard practice for maximum areal devastation and minimal fallout and by the time Frodo gets there most of the radiation has already dissipated and he can just trot along completely devastated and empty landscape. First 48-72h are the most dangerous and after 14 days it's mostly safe.

Depending on the size of Mordor more than one nuke might be needed. Based on Google, Mordor seems to be bigger than Poland so an ICBM capable of carrying multiple warheads, up to 10-15, would be more suited for maximum areal destruction.

maybe for other worlds, but the kayfabe of Tolkien's works is that they are historical accounts from our own real world. canonically, thousands of years after the end of the Third Age, Eru Ilúvatar sent himself to Middle-earth in the form of a Man who was his son, and he was called Jesus Christ; at one time Tolkien said that was the beginning of the Seventh Age, which we are currently in

essentially that means that whatever happens in the real world, or at least wherever happened between events recounted in the Bible up to 1954, is canonical to LotR. so we have explicit confirmation that it would have been physically possible, given the proper technology, to drop a nuke on Sauron

but the things is that it still wouldn't have happened. because recognizing the danger of great power and seeking to use it to your own advantage to dominate your enemies, rather than acknowledge that it should not be used by anyone, is what the dang book is about. the whole point is "don't do that exact thing." anyone in Middle-earth who would use an atomic bomb either is Sauron, or serves Sauron, or would at best defeat Sauron in order to take his place

https://en.wikipedia.org/wiki/Project_Plowshare

unless the ring is destroyed.

I guess the temperature generated by a thermonuclear device should by far exceed that of the fires of Mt. Doom. So with conventional physics, the ring should be destroyed. With magic getting in the way, the destructibility of the ring could be directly linked to the actual fires of Mt. Doom, though. Anyway, one of the more unhinged noncredible contraptions dear old Dr. Strangelove Edward Teller dreamed up could destroy all of Middle Earth, which would sufficiently diminish the power of Sauron through the extinction of all species susceptible to the ring's control, even if the Ring stayed intact, and he survived. This would surely piss him off big time, and therefore be very funny.