Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: annie123 on 09/11/2019 22:29:35
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I heard someone today saying, when talking about Voyageur 2, that it would go on travelling in space for billions of years. This suggests that it will never break down/'decay,change. is this true of anything that gets into space?
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I heard someone today saying, when talking about Voyageur 2, that it would go on travelling in space for billions of years. This suggests that it will never break down/'decay,change. is this true of anything that gets into space?
All particles have a half-life of sorts, but given what space probes are made of, it is not of any real concern. Billions of years doesn't begin to touch that.
Shorter term, the probes are continuously bombarded with bits of matter it runs into, solar rays, and all the same sorts of things that make life inhospitable to humans (breaks us down similarly). That sort of thing will age the probes faster than the decay of its materials, and it will always be surrounded by material since it has nowhere near the speed needed to exit the galaxy.
Our galaxy is scheduled for being eaten by our neighbor in the next 5-15 billion years (swallowing takes a while), and this process has the potential to fling either Voyager or our sun in some random direction, into the void or into the thick of it where the bombardment is greater.
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talking about Voyageur 2, that it would go on travelling in space for billions of years. This suggests that it will never break down/'decay,change. is this true of anything that gets into space?
In a vacuum there is no friction or resistance to motion so even if Voyager breaks down or changes what is left will keep on moving at the same speed - unless it hits something.
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So if an astronaut left the space station and couldnt get back, or anyone's body was just let go in space would it freeze and stay like that for ever? Would it move or stay in one place?
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So if an astronaut left the space station and couldnt get back, or anyone's body was just let go in space would it freeze and stay like that for ever? Would it move or stay in one place?
Being in a suit means you're under pressure, so the body might suffer a similar fate as one on Earth at a similar temperature, in an enclosed container. Space isn't particularly cold or hot as there is no matter to give it temperature, so the eventual temperature of the body in the suit will depend on how much time it spends in the sun or shade.
As for where it will go, a body let go outside a space station will drift nearby it for quite a while, orbiting in its own path not much different than the station. It would take considerable energy to actually push a human outside of Earth's gravity well. If it orbits near the space station, the orbit will probably decay over a long time and then fall to Earth, just like the space station will if not pushed now and then.
It would move, yes. There is always mass (like Earth or the sun, or whatever) accelerating every object. Nothing that is stationary (in some frame) can remain so for any length of time. I can thing of zero examples of a non-accelerating object. If an object (body?) was near a space station, but somehow stationary relative to Earth, it would immediately just fall to Earth.
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This suggests that [the Voyager spacecraft] will never break down/'decay,change
The Voyager spacecraft (1 & 2) are powered by a plutonium-238 "battery". Plutonium is radioactive, and decays spontaneously whether it is on Earth or in space, with half of it decaying every 88 years.
The rest of the spacecraft does not spontaneously decay, but will be slowly damaged by the impact of the dust that travels around in space at speeds far higher than a bullet. After the Plutonium power is turned off, heating will be lost, and the temperature of the electronics and instruments will drop to near absolute zero. This will cause thermal strains and cracking, which means the functioning spacecraft could never be resurrected, even if power and temperature could be restored.
See: https://en.wikipedia.org/wiki/Voyager_1#Power
if an astronaut left the space station and couldn't get back, or anyone's body was just let go in space would it freeze and stay like that for ever?
It is commonly seen in science fiction movies - someone is thrown out the airlock, and they freeze solid in a few seconds.
If space exposure occurs near the Earth, in full sunlight, the average outside temperature is about -15C (the average of intense sun on one side, intense dark on the other). A human in space would lose consciousness in under 30 seconds due to lack of oxygen, and be dead in 4 minutes.Evaporation of water from exposed surfaces will cause ice crystals to form on eyes and in the lungs. But it takes a while for a human body to cool down from 37C to -15C, and meanwhile, the gut bacteria will have a party. In the longer term, exposure to UV light damages organic chemicals. As the body slowly rotates, repeated thawing and freezing cycles will turn the body into mush (less damage if it is rotating fast enough to stay completely frozen).
An astronaut in a spacesuit has an air supply, has air conditioning and is is fairly well insulated. They will survive until their air runs out. Their bacteria will have a much longer party, generate their own heat, and will cause considerable decay before the body finally freezes over.