Space Radiation

Palomar · 2003-08-12 07:32:41

*Okay, what causes radiation in outer space (LOW-TECH ANSWERS, PLEASE)? I tried to relocate the posts (from months ago) regarding the extreme levels of radiation around Jupiter, and how an astronaut on Ganymede would be dead from radiation poisoning in under 40 minutes.

By what natural processes is radiation created? Is it all due to stars? And how can planets emit radiation (?); are they reflecting the radiation which originated from the host star?

--Cindy

dickbill · 2003-08-12 09:21:51

In the large sense, radiation can be any particle or photons.
The "particles" are usually ionized atoms, atoms lacking electrons, like helium nucleus also called alpha particles. The sun emits a lot of these, in addition to other atomic nucleus, protons, neutrons and neutrinos. Given their speed these particles are very energetic and when they hit our body, they can make a lot of damage by killing the cells (which can be better than damaging the DNA, see further).
The term "radiation" has definitevely a medical connotation, as people tend to associate biological dammages to a radiation. For example the sun emits a lot of neutrinos, but this neutrino "radiation" doesn't affect us, the neutrinos are so small and non-reactive that they just traverse our body without damaging anything, billions of them tracerse our body. So some "radiation" can be more or less harmless depending of a lot of parameters. Radiations have different origin, in the sun it is the nuclear fusion reactions , on Earth it is the disintegration of unstable (radioactive) element. I think the first radioactive element discovered was the radium, discovered by Ms Curie before the 2nd WW, and these radioactive elements disintegrate by fission in "radiating" different kind of particles.
The term "radiation" can be extended to photons, as we call a gamma irradiation, a X-ray irradiation or even a UV irradiation. So if you get a sun burn, you have been irradiated by UV.

A final note to the medical connotation of radiation. It is generally preferable to receive a slow moving, big particle than a small, fast moving very energetic one. A big particle when it hits your skin, will probably kill the cell like a bullet, it's too big to enter further your body without interacting with an atom. So a skin cell is dead but you can replace it quickly, no big deal. Of course too much of that can be letal too.
A small energetic and fast particle, or an energetic gamma photon, being small and fast, can enter deep into your body, several centimeter or more sometimes, and being small, rather than killing the whole cell, the particle just destroys locally our molecules, that could be our DNA, and if it is the DNA which has been hit, then the cell survives but with a damaged DNA, a mutation that could cause cancer. So the effects can be long term and pernicious with some radiations.
The UV radiation causes DNA damage too, but in the course of evolution, the animals being constantly exposed to the solar UV, a biological mecanism with a specific DNA repair proteins, has been set up to remove these DNA damages from our cells. I think that everyday in normal people (some people lack the DNA repair mechanism and cannot sustain the sun), hundreds of these DNA damages are fixed and removed, otherwise we would get a skin cancer everyday.
But there is limits of mutation that animals can sustain and repair, however, a famous case of bacteria has been discovered. It was the famous Deinoccocus Radiodurans, discoved in Gamma irradiated sterilized food, actually not sterilized at all because deinoccocus was at ease with the gamma irradiation. That bacteria has mannaged to build a DNA repair system properly incredible, the purpose of which we are not sure yet (supposedly to survive high dessication which can destroy the DNA too). This is the reason why this bacteria, if imported on Mars, despite the intense dessication and UV radiation on the surface, would not be killed. Even bacteria less resistant than Deinoccocus have survived Mars condition actually.

RobertDyck · 2003-08-12 10:40:37

Hello Cindy. dickbill's explanation is pretty good, but you also asked where radiation around Jupiter comes from. Jupiter doesn't give off radiation, but its magnetic field traps radiation from the sun. Radiation from fusion in the sun can be proton, neutron, electron, or ionized atoms. Electron radiation is not much to worry about; it can't get through the outer layer of our skin. Neutrons can only survive a few minutes outside an atom, so in space a neutron will break up into a proton and electron before it passes the orbit of Mercury. Neutrinos are also generated, but they are so small and have so little mass that most of them pass right through the entire Earth without reacting with anything. It's protrons and ions that you have to worry about in space; and they have a positive charge and mass. The strong magnetic field around Jupiter traps them in orbit around Jupiter. The trapped particles build up until their concentration is much greater than interplanetary space. In fact, as they fall into Jupiter's gravity they speed up, so the radiation in orbit is also much faster than interplanetary space. Since it?s charged, the magnetic field accelerates it as it falls as well. Earth also has radiation belts, but Earth's magnetic field and gravity aren't as great as Jupiter so the radiation belts aren't as intense. This is actually a hazard for anyone designing a mission to Mars. A slow but efficient engine like an ion engine could slowly spiral from low Earth orbit to escape velocity, but an ion engine would take 3 months to leave. Astronauts cannot stay in Earth's radiation belts for months, they would die. Passing through in minutes like the Apollo astronauts is fine, but they can't linger in the radiation for months. Yes, the difference between Earth's radiation belts and interplanetary space is that significant.

Also, yes, Earth does have more than one belt with a bit of a gap between each one. Earth's magnetic field, like a bar magnet, does pass through the center of the Earth at the poles. When radiation from the belts wanders close to the poles it is drawn down into the atmosphere. As it's drawn down the magnetic force accelerates the radiation so it travels even faster as it is shot into the upper atmosphere. When it strikes the atmosphere it caused the air to glow, that is the aurora. Proton radiation will combine with electrons from the air to form hydrogen, which at that temperature will burn with oxygen in the air to form water. Therefore, solar wind is one source of new water for our planet. Of course some water in the very top of the atmosphere is broken by radiation into hydrogen and oxygen. Some of that hydrogen is whacked so hard it achieves escape velocity, and is blown off our planet. So solar wind both delivers new water and removes existing water. Some of that ionized hydrogen (protons) is trapped by Earth's magnetic field and pulled back in, to be added to our radiation belts, which eventually wanders to the poles to return as aurora. It's all a complex dance.

Palomar · 2003-08-12 13:41:34

Robert: "It's protrons and ions that you have to worry about in space; and they have a positive charge and mass. The strong magnetic field around Jupiter traps them in orbit around Jupiter. The trapped particles build up until their concentration is much greater than interplanetary space. In fact, as they fall into Jupiter's gravity they speed up, so the radiation in orbit is also much faster than interplanetary space."

*I see.

Robert: "Proton radiation will combine with electrons from the air to form hydrogen, which at that temperature will burn with oxygen in the air to form water. Therefore, solar wind is one source of new water for our planet. Of course some water in the very top of the atmosphere is broken by radiation into hydrogen and oxygen. Some of that hydrogen is whacked so hard it achieves escape velocity, and is blown off our planet. So solar wind both delivers new water and removes existing water."

*I certainly did not know this!

Robert: "It's all a complex dance."

*That's an understatement. Now where's my aspirin bottle?

Thanks, dickbill and Robert.

--Cindy

SpaceNut · 2015-01-31 20:45:05

UNH Scientists Launch "CubeSats" into Radiation Belts

Knowledge to be gained for sure....

Mars_B4_Moon · 2023-08-26 07:35:54

IceCube-Gen2: 8 Cubic Kilometers of Ice, 5 Times the Sensitivity

https://www.universetoday.com/162915/ic … nsitivity/

The IceCube Neutrino Detector is an observatory unlike any other. Using sensors embedded inside a square kilometer chuck of Antarctic ice, it detects tiny particles called neutrinos, which rarely interact with ordinary matter and are incredibly hard to capture. IceCube has had several major successes in the last few years, including this summer’s announcement of a neutrino map of the Milky Way galaxy. But scientists are pushing up against the limits of IceCube’s capabilities, and plans are in the works for IceCube-Gen2: a detector 5 times as sensitive and 8 times as large, with a radio antenna array across four hundred square kilometers. IceCube Gen2 will increase the number of neutrino detections by an order of magnitude, and will be able to better pinpoint the sources from which the neutrinos are emitted.

Last edited by Mars_B4_Moon (2023-08-26 10:34:47)

tahanson43206 · 2023-08-26 08:19:53

For Mars_B4_Moon re #6

Thanks for giving this topic by Palomar another viewing, and! thanks for the report on the plans to build a new and much larger neutrino detector!

That *** is impressive science, on any scale !!!

(th)

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#1 2003-08-12 07:32:41

Re: Space Radiation

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