OT: Ceres more interesting than previously thought

[douglas]

Kamog said:
I thought depleted uranium emits its own radiation, doesn't it? So although it may stop outside radiation, it probably won't be very healthy to live inside walls made of the material.

Uranium has an extremely long half-life under normal conditions (4.47 billion years), so it really doesn't emit much radiation. What little it does emit can probably be blocked by a very thin layer of something else. The primary health concern with uranium is about its chemical properties.

Kamog said:
Also, I don't understand why radiation that passes through the human body won't do any damage. Wouldn't it still do damage as it passes through, just like a bullet that passes through the body?

A bullet passes through the body because it's massive and fast enough to push the body out of its way. An atomic or smaller scale particle would pass through the body because it's so small or interacts so little with most matter that the body is effectively empty space as far as that particle is concerned. For example, there are trillions upon trillions upon trillions of neutrinos passing through your body every second, but they are so miniscule, light, and electromagnetically neutral that they don't actually "hit" anything on their way through. If you sent a stream of neutrinos straight through the Earth, going directly through the core, the vast majority of them would go all the way through and come out the other side without interacting with any of the matter in the way in the process.

[narf poit chez BOOM]

Interesting excercise: Your body is made up of molecules. These molecules have empty space between them. Molecules are made up of atoms. These atoms have empty space between them. Atoms are made of protons and electrons. Except (Not really) in the case of neutrons, these protons and electrons have empty space between them.

The pattern probably continues.

In other words, we're mostly made up of empty space.

[dogscoff]

Any kind of radiation harmful to humans has to react/be blocked by something on the order of the thickness of the human body,

Line the hull with human bodies? A massive orbital cemetary, where the deceased are more than just worm-food...

Someone mentiond story referrencing tranparent shup hulls, the only one i can think of was "ringworld Engineers" by Larry Niven.

It was a short story - probably only 1000 or 2000 words. If I remember rightly some guy was sent to investigate a mysterious and deadly stellar phenomonomnom of some sort, and was given a ship to do it in.

I've never read any novels by Niven so I doubt it's him, although if he's ever featured in any short-stroy anthologies I might have stumbled across him without realisng it. I'll take a look at my bookshelf later.
*** far as short stories go I've read a lot of Asimov, a fair bit of Bradbury (Illustrated Man was his, wasn't it?) and various others. From memory I have "The Golden Apples of the Sun" on my bookcase. Was that by one author or a collection of people?

[Wolfman77]

Radiation only damages stuff it hits. Gamma radiation being made of photons, doesnt occupy much space (compared to a neutron for neutron radiation). Atoms are mostly empty space, so there is less chance of it hitting anything. Photons also have less mass than neutrons, but their damage is due to the high energies. At least thats how I understand it right now, I'm sure sure someone else could explain it better.

Depleated uranim (DU) does release some radiation, but the amount is considered safe. That, of course, depends on who you ask. U235 is the radioactive part, Uranium ore in nature is about .7% U235 and is considered safe to mine (with certain precautions I think). DU contains .2-.4% about half of what is found in nature, but still requires it to be stored, long term, as low level radioactive waste.

Uranium ore is about as abundant as tin, and durring refinement about 89% is left as depleated uranium. The US has ove 775,000 tons of it.

[ToddT]

Someone mentiond story referrencing tranparent shup hulls, the only one i can think of was "ringworld Engineers" by Larry Niven.

It was a short story - probably only 1000 or 2000 words. If I remember rightly some guy was sent to investigate a mysterious and deadly stellar phenomonomnom of some sort, and was given a ship to do it in.

I've never read any novels by Niven so I doubt it's him, although if he's ever featured in any short-stroy anthologies I might have stumbled across him without realisng it. I'll take a look at my bookshelf later.
*** far as short stories go I've read a lot of Asimov, a fair bit of Bradbury (Illustrated Man was his, wasn't it?) and various others. From memory I have "The Golden Apples of the Sun" on my bookcase. Was that by one author or a collection of people?

[/quote]

Hmm golden Apples not sure i herad of it, deffinitley haven't read it.
ok as for Ringworld Engineers< before i posted these i went and dug out the book from storage, as i suspecte it was the Sequal to Ringworld, both are noveels by Larry Niven. Ring world is copyrighted in 1970, the copy i have was printed in December 1981. Ringworld Engineers was copyrighted in 1980 and the copy I have of that is May 1983, seventh printing, there is the nineteenth.
I have around 450 to 500 books on scifi and i read who knows how mny more, i even have the book Tin Woodman which the Episode Tin Man in STNG is based on.

As for threads topoic i don't remeber all the numbers but there have been Gamma ray bursts detected that where so powerful if they had been aimed in our direction from a few hundred lightyears out, would have vaporized the side of the earth facing it.

[Phoenix-D]

DU doesn't emit enough radiation to be really harmful- you'd get more exposure just by being outside in most cases.

And in the cases where you would get a dangerous dose, the radiation would be a secondary concern..the real problem there is simple heavy metal poisoning.

[NullAshton]

narf poit chez BOOM said:
Interesting excercise: Your body is made up of molecules. These molecules have empty space between them. Molecules are made up of atoms. These atoms have empty space between them. Atoms are made of protons and electrons. Except (Not really) in the case of neutrons, these protons and electrons have empty space between them.

The pattern probably continues.

In other words, we're mostly made up of empty space.

To make this clearer, look at an atom like a football field. The electrons are on the outside. Now take a marble, and put it at the center of the football field. That's the nucleus. About 99.99% of matter is empty space. I guess you could say the whole universe is an airhead.