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Strange Bacteria Sustains Itself Without Sunlight
Hahnsoo writes "A colony of bacteria found 2.8 kilometers below the Earth's surface in a South African gold mine is able to sustain itself without energy from the Sun. While sub-surface colonies of microorganisms utilizing sulfur (mostly near deep sea hydrothermal vents) is not new, this particular colony is unusual. The colony does it by relying on radioactive uranium to split water into hydrogen gas. Thus, instead of solar energy and photosynthesis, this species relies on radioactive materials and sulfur/hydrogen to facilitate its energy needs. There is some speculation about life on other planets in the article as well."
Yes, these are natural uranium ores in South Africa.
The radioactive half-life of uranium is in the order of 100 millions of years for the two common isotopes of uranium that the radioactivity of itself is not very significant.
Radioactive materials used for power-production from radioactive decay itself (see radioisotope thermoelectric generator) use radioisotopes with half-lives of tens to hundreds of years.
radioactive materials absolutely do not rely on sunlight. They rely on big huge stars to make big fat elements, then explode spreading them all over the universe where the coalesce into planets like the Earth.
The hydrogen and sulfur components are likely released as part of volcanic activity. which is not sunlight driven, although it is driven through the energy released due to the effect of solar gravity on the Earth's core.
I'm not really sure what point you're trying to drive here. Likely the bacteria's ancestors required sunlight to survive, if you are so interested in associating sunlight with everything.
“Common sense is not so common.” — Voltaire
(Slashdotters who already know this can feel free to ignore it. Everyone has to learn science sometime, if you had the good fortune to learn it years ago no reason to jump on someone who hasn't yet.)
Yes, uranium is naturally radioactive. Much of nature is naturally radioactive, including you, incidentally. There is a certain amount of what is called "background radiation" around you twenty-four hours a day, seven days a week, there would still be even if no human had ever drawn a single breath. Uranium just happens to be quite a bit more radioactive than you are, owing to its nuclear structure.
Now, uranium like most metals doesn't come in handily available lumps in the natural world, but is found in ores: the ore is called pitchblend, in the case of uranium. Humans extract pitchblend (at a ratio of a few pounds of pitchblend to a lot of tons of boring old rock), extract the uranium, and then refine/enrich the uranium so that we get the exact isotopes of it we need for our nuclear power/weapons needs. (Isotopes are the same element, except with a different number of neutrons in the nucleus. Different isotopes of elements have vastly different radioactive properties. For example, the most common isotope of hydrogen isn't radioactive at all, and your body contains a heck of a lot of the stuff. The least common isotope of hydrogen, tritium, has two neutrons in it, and is used for making hydrogen bombs.)
So there are essentially three ways an atom can alter the configuration of its nucleus and release energy. Number one, it splits off into two atoms (fission). Number two, it fuses with another atom (fusion). Number three, it spits out something that was in its nucleus (radioactive decay -- there are a couple of types of this, producing radiation of various levels of danger -- alpha decay, for example, can be stopped with a piece of paper, gamma decay on the other hand will penetrate a meter of concrete). You can cause fission by manipulating radioactive decay in the right way, but it will happen really bloody slowly over time regardless -- uranium, for example, has a half life in the millions of years, which means that of a given sample it will take millions of years for one half of it to radiate and transform into whatever the next step is. Now, a bit of pitchblend just sitting on the counter isn't going to be useful for much of anything, although if you handle it for a few months or years you're at an elevated risk of getting cancer (and if you get radium, a radioactive gas, in your lungs, well, its less than good for you). So you can't, say, just chuck it in a specially designed miniature nuclear power plant and have it power your refrigerator. But a comparitively small amount of the concentrated, refined stuff (a few tens or hundreds of kilograms, as I recall), plus a nuclear plant designed to accelerate the fission faster than it occurs in nature, can literally power a city for years.
Nuclear power, even with the downside of producing harmful radiation (which is almost totally controllable, incidentally), is already very useful. Several countries and many, many communities are dependent on it to keep the lights running, the computers playing WoW, and air conditioners conditioning, the welders welding, and all those electricity-using things modern society depends on. If you're an environmentally concerned sort, you might also be happy to know that it generates extraordinarily little pollution compared to the refinement and combustion of fossil fuels.
This lesson in nuclear chemistry has been brought to you by the letter U and the number 235.
Help poke pirates in the eyepatch, arr.
Does that mean, that on Earth the "big elements" are actually from big OLD stars from Long Long ago..almost at the time of big Bang??
Yes. Every element heavier than helium was created primarily either in the core of a star (up to iron), during a nova (almost everything else) or as a decay product of the radioactive decay of a heavier element (which was created during a nova or similar event).
The big bang created hydrogen and a little helium; we have stars to thank for everything else.
It's official. Most of you are morons.