View Single Post
Old 02-08-2013, 12:49 PM   #59
Ring of Famer
W*GS's Avatar

Join Date: Jan 2004
Location: Earth
Posts: 20,751

Originally Posted by mhgaffney View Post
The discovery of cometary x-rays
Now, to the real science:

Comets emit X-rays, indicating they are not cold.

McCanney claims in that book (on page 1!) that he predicted that comets would give off X-rays, and also that the side of the comet facing the Sun would be the source of these X-rays. This has to do with his claim that comets are plasma balls, electrically coupled with the Sun. Amazingly, years later, it was found that not only do comets give off X-rays, but they comes from the sunward side! Could McCanney have been right?

Nope. Well, his prediction was correct, but for the wrong reason. For a prediction to be counted as a success, it has to be exclusive; that is, no other theory could account for it. The problem is, there are plenty of ways a comet could give off X-rays, even though it's cold. For one, comets get smacked by the high-energy particles from the Sun's solar wind. Ice, when hit like that, fluoresces; that is, gives off light. At those energies, the light given off is in the form of X-rays. So naturally, the part of the comet facing the Sun is where the X-rays come from.

McCanney is very derisive in his book about this. He says: "Let's get serious... x-rays coming from a docile little snow ball?" But think about it: when you go to the dentist, she isn't heating the X-ray machine to a million degrees to get it to give off X-rays! Those machines work by accelerating electrons to high speeds and slamming them into metals. When the electrons hit the metal, they slow down and emit X-rays in the process. So there are other processes which generate X-rays besides temperature, despite what he is saying there. Ironically, his own process is not thermal either, so why is he so derisive of cold comets giving off X-rays? Oh yeah: it's because he's wrong.
W*GS is offline   Reply With Quote