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View Full Version : Life, Europa and Jupiter's Deadly Radiation



Mr. Milton Banana
2004-Jun-05, 03:14 PM
I had been wondering about this for a while now...

Given all the talk about possible life inside Europa, how can this life be protected from radiation? I've read that Jupiter's radiation belt is 1,000 times stronger than what's needed to kill a human.

Is Europa's icy crust really enough to shield any underground ocean from radiation? And wouldn't any collisions or cracks in the crust let radiation leak in?

:-k

Eroica
2004-Jun-05, 03:26 PM
Europa is about 671,000 km from Jupiter. Maybe that's far enough away? :-k

Amadeus
2004-Jun-05, 04:47 PM
Plus just because the radiation could kill a human who knows what kind of life coul have evolved there?
The radiation could be a vital energy source in a life cicle.

ToSeek
2004-Jun-05, 05:58 PM
Europa is about 671,000 km from Jupiter. Maybe that's far enough away? :-k

No. Europa's surface gets about a million rads a day, where 400 is the 50% lethality level for a human being. The good news is that the ice is a very good insulator and keeps most of the radiation from getting into the depths.

Mr. Milton Banana
2004-Jun-05, 06:20 PM
Europa is about 671,000 km from Jupiter. Maybe that's far enough away? :-k

No. Europa's surface gets about a million rads a day, where 400 is the 50% lethality level for a human being. The good news is that the ice is a very good insulator and keeps most of the radiation from getting into the depths.

The operative word being "most". And what of the little bit of radiation that does get in, insofar as cracks in the ice and collisions by meteors? How long would it last, if it contaminated any underground ocean?

Mr. Milton Banana
2004-Jun-05, 06:23 PM
Plus just because the radiation could kill a human who knows what kind of life coul have evolved there?
The radiation could be a vital energy source in a life cicle.

Good point. We have to remind ourselves that we can't just look at life in terms of what we've seen on Earth. That would be rather narrow-minded thinking.

One Day More
2004-Jun-06, 01:27 AM
They could be like some insects or something that has a natural immunity against radiation. For example dolphins and whales, theroratically, evolved from land animals, and became adapted overtime to their watery habitats! They happen to be my favourite creatures! ;)
After all, aren't scorpians immune to at least some radiation? Or was it something else? :-k

Master258
2004-Jun-06, 01:39 AM
The name of this thread would be a good sci story.

eburacum45
2004-Jun-06, 02:19 AM
The extremophile bacteria Deinococcus radiodurans is probably the most radiation resistant Earth organism; ithas a tight protein case around each of its chromosomes so that the DNA has less opportunity to shuffle itself when it is disrupted by radiation.

If it were possible for Europan life to evolve similar protection it would be less likely to suffer constant genetic damage; similarly it may be possible to engineer such radiation resistance into future space-dwelling humans...

however, deep under the Europan ocean, life would be pretty much safe from the radiation from Jupiter's magnetic field ; we are not talking about radioactive isotopes here, but charged particles trapped in a field. I believe this sort of radiation would not penetrate Europa's ice and ocean layers very well.

ttoensing
2004-Jun-06, 11:13 PM
Depending on how we define "life", maybe radiation is no factor or even sustains Europa's creature(s)?!?

Hmmm....shades of the movie Alien...

Spacedog
2004-Jun-06, 11:57 PM
i'm imagining a creature that requires radiation to survive
so that in the earth year 10,000,001
the obelisk has a fulcrum
effective negotiation

Jpax2003
2004-Jun-07, 04:01 AM
however, deep under the Europan ocean, life would be pretty much safe from the radiation from Jupiter's magnetic field ; we are not talking about radioactive isotopes here, but charged particles trapped in a field. I believe this sort of radiation would not penetrate Europa's ice and ocean layers very well. What I was just gonna say.

Incidentally, the radiation tenth value thickness for water is 24 inches. That means that 2 feet of water will block 9/10 allowing only 1/10 of incoming gamma radiation and, therefore, 12 feet will only allow 1/1,000,000 of incoming radiation. The ice is less dense but not by too much, so I am guessing that packed ice would still only be double that thickness at the most. Of course this is in reference to gamma radiation. If the only radiation is charged particles, then you need to take that into account.

from www.ki4u.com link to this page (http://www.radshelters4u.com/index3.htm#b2).

The denser and thicker the barrier substance, the better its shielding properties. Where every 3.6" of earth cuts the incoming gamma radiation in half, thus doubling the PF, it would only take 2.4" of concrete because it is even denser. Of course, earth is cheaper, but where concrete had been used in the construction of a shelter it'll be providing even additional barrier protection. Also, the tenth-value thickness, in inches, for steel is 3.3; for concrete, 11; for earth, 16; for water, 24; for wood, 38. That means that where you have those thicknesses you'll have only 1/10th as much gamma radiation pass through with that barrier material.

bobjohnston
2004-Jun-07, 05:04 AM
I agree with Jpax2003. If you apply those numbers, you'll probably find that the radiation penetrating the expected thickness of ice on Europa is far less than the natural radioactivity of the water and rock of Europa. Charged particles won't penetrate that much ice, either; they can induce secondary radioactivity, but that will be mostly confined to the surface of the ice. And additionally, as eburacum45 alluded to, it is not unreasonable for life forms to have cellular repair mechanisms to survive such radiation levels (this is easier for simpler life forms).