h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

you remember 1930 europe? bloggs

Appy my family wittnessed the events of those times.
Oetz

23:00 Folks local
beepyes time
Good Night Sleep Tight
Oetz till morrow

>>I've tried living backwards and I don't seem to make any progress in past for some reason. One thing's for certain. It doesn't help me remember to take out the trash.<<
Living backwards.. it could be very useful, if you could skip parts! (I did mean Mars

In the spirit of the original thread topic:

An element with a longer radioactive half life is more dangerous than one with a shorter half life.


- JD

Good to be back on topic, JD.

taken

But where is the wrong?

An element with a longer HL is not necessarily more dangerous than one with a shorter one.

- JD

Nice Meeting...see you around the cosmos sometime.
Bye Oetz

ah ha, but wouln't that be subjective?

Which is more dangerous, a harmful substance or a less harmful substance that hangs arround twice as long?

answer: depends on how you look at it.

Depends in which way they are dangerous.

An alpha emitter with a half life of (this is just an example physics s) 20 years is much less dangerous than a gamma emitter with a half life of 40 seconds.

Liam.

yes but you'd only have to avoid the gamma emitter for 80 seconds. That's what I mean by it being subjective.

Erm. No. After 80 seconds a quarter of the material would still be radioactive.

Liam.

And if you swallowed the alpha emitter you'd be pretty much done for - gamma rays have enough energy to pass through you, alphas don't, hence if they do get inside you...seyonara


It's why they don't allow food and drink in school science labs

"Erm. No. After 80 seconds a quarter of the material would still be radioactive."

you know what I mean

I'm still in a 96hour monday

Nuclear Physics 101 Notes:

Gamma radiation is ionizing. Ionization destroys tissue, proteins and such. You will not survive exposure to gamma radiation for very long. You can shield yourself from Alpha radiation however.

The question of the relative harm done by low level,long term as opposed to intense short term radiation sources is resolved by recognizing that long term sources kill slowly while intense short term sources kill right away.

The first will affect your longevity and your progeny. The second will affect your longevity but you probably won't have any progeny subsequent to exposure unless you can pursuade yourself that something resembling mutant mucus might be progeny.

The upshot is don't mess with nuclear physics moron!! It's not a genie liberated from a lamp. It's a monstrocity waiting to obliterate life as we know it. It's a peek at the universe before life could survive in it. It's bad dope!

Didn't mean to cause a stir. I shoud've known better than to post that sort of thing around here in the first place.

Anyway, I'm glad that my point was well-taken - that a radioactive element's danger to humans (or life in general) is dependent on much more than just it's half life, a fact that escapes many lay people (no elitist mentality here, it used to escape me too, until I started studying it in college - it is, after all, nuclear physics ). Other such factors of critical (heh) importance are the afore-mentioned type of radiation the nuclide is decaying with (alpha, beta, gamma, neutron - usually a combination thereof) and the relative energies of the decay particles (which can change drastically in the presence of other types of radiation or radioactive elements). Chemical properties as well as nuclear properties of the element can even have a drastic effect on the human body, too. If the element is likely to stay in the human body a long time and be concentrated in an area of the body, more damage can be done. I was just trying to say that touting an element's half life as an expression of it's danger is, in turn, dangerously misleading.

Ok, now I'm lecturing again. I hate it when I do that. By the way, I don't think people that mess with nuclear physics are "morons," but maybe I'm a little biased there.

To continue as we were, one could simply mine most of snopes.com for more stuff - I'm trying to think of something more original though.

Ok, here's something that's wrong: super-wealthy rock musicians make most of their money from record sales (they don't, the vast majority of their income is from tours, though there are a few exceptions).

- JD

One last one and we can leave the nuclear physics alone

>alpha, beta, gamma, neutron

beta = neutron, also alpha = helium nuclei, and gamma = high energy EM radiation.

Liam.

We can leave the nuclear physics when we get it right.

beta = electrons

(Well, beta- = electrons, if you want to be pedantic. beta+ = positrons).

Dang nabbit.

Liam.