Question about radiation on Mars

Leovinus · Oct 7, 2005

I think I read somewhere that Mars gets more surface radiation because of the thinner atmosphere and lack of magnetic field. Now is most of this radiation from the Sun or is it cosmic in origin? If the radiation is from the Sun, then I have this what if question: If Mars were twice as far from the Sun as it is now, would the surface radiation be reduced? One would expect that to be the case. <div class="Discussion_UserSignature"> </div>

Saiph · Oct 7, 2005

If the radiation was from the sun, the total radiation hitting mars is 4x weaker per square meter. however, due to worse shielding, a much higher percentage that may hit the surface. For example, if the earth blocks 10x more radiation than mars...mars gets more surface radiation. As for the actual origin...likely from the sun IMO, but I've no real basis for that other than an educated guess. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

vogon13 · Oct 7, 2005

Solar UV has apparently charged the surface materials with the 'superoxidizing' materials found by the Vikings. The lack of an ozone layer has allowed this despite the weaker sunlight. Magnetic field absence would effect solar and cosmic radiation, but keep in mind, stuff like alpha particles is pretty easy to stop with atmosphere. I don't know about the transparency of the Martian atmosphere to x-rays, but suspect I am happier on Earth in this regard. IR, and radio not of any great import here, beta and gamma rays probably absorbed in martian atmosphere, but I'd 'Ask Jeeves"' before I emigrated. <div class="Discussion_UserSignature"> TPTB went to Dallas and all I got was Plucked !!So many people, so few recipes !!Let's clean up this stinkhole !! </div>

pyoko · Oct 8, 2005

Without googling for it, I'm going to ask - Does Mars really have no/ little magnetic field? How was this measured? Without a satellite or probe directly measuring it, I would assume that Mars has a similar field to Earth. Being the most similar planet to Earth in our Solar System, having 2 poles etc etc. <div class="Discussion_UserSignature"> -pyoko the duck It is by will alone I set my mind in motion. </div>

jatslo · Oct 8, 2005

The red rovers are not designed to find life, and I hope you are wrong about the aspects of possible life, even though it is possible. The aspect of life on the planet Mars makes for publicity which equates to funding.<blockquote>In reply to:<hr />This is why Mars is dead, BTW. Those superoxides penetrate to some depth most likely, destroying anything organic. And despite the last 2 years of surface exploration and remote imaging, not the slightest sign of anything living has been found. And that's exceedingly unlikely to change, too.<hr /></blockquote>

Philotas · Oct 9, 2005

Tell us where the methane come from. Life or vulcanism? Well, if it`s vulcanism then that would again make new possibilities of life. The rovers weren`t designed to find life, no one expected them to find life nor fossils. MSL on the other hand is. Wait for that and confirmation of what sub-surface Mars is like before thinking about concluding that there isn`t life on Mars. <div class="Discussion_UserSignature"> </div>

bonzelite · Oct 9, 2005

mars is very electrically active. a good article on dust devils and earth-based tornadoes goes into this: http://www.holoscience.com/news.php?article=zg70y10m&keywords=%20magnetic%20field#dest i'm sure the UV would kill you pretty good, though!

bonzelite · Oct 9, 2005

[The red rovers are not designed to find life, and I hope you are wrong about the aspects of possible life, even though it is possible. The aspect of life on the planet Mars makes for publicity which equates to funding.] yep. that is right. it is too bad that we have to sell constantly the idea of "life everywhere may be possible" in order to simply explore and discover -life or not. that sort of lack of interest or attention span of people generally, unless you coat everything with some shiny object or pot of gold incentive, makes me sick. it seems you cannot do anything for the sake of discovery itself. everything must be "justified." i'd rather they just open up space resorts and tours, space casinos, around the earth to fund really awesome projects that NASA would never attempt to do in it's bureaucratic dinosaur state.

paleo · Oct 9, 2005

"This is why Mars is dead" Yes. I agree. If there is a smidgeon of hope, however, it's that the rovers would not have detected life even if they had landed on many parts of the Earth.

jatslo · Oct 10, 2005

that sort of lack of interest or attention span of people generally, unless you coat everything with some shiny object or pot of gold incentive, makes me sick. it seems you cannot do anything for the sake of discovery itself. everything must be "justified." Earth is going to be consumed by are own Sun one day and humanity will not survive, so you would think that colonizing space would be our highest priority.

jatslo · Oct 10, 2005

That's largely correct. UV radiation on the Martian surface is far higher than the earth because there is no effective ozone to stop it as there is on earth. Nor is there much blocking of x-rays, cosmic rays, or much else, including solar radiation from flares, or from any source, the sun or galactic origin. Stevehw33 – You are an archeologist, right? Has it ever occurred to you that the reason dinosaurs (general biology of the time period), were so large was because the Earth was less efficient at blocking harmful radiation? Meaning, there larger mass was better at absorbing radiation; they homogeneously evolved that way because of higher radiation levels.

phaze · Oct 10, 2005

<blockquote>In reply to:<hr />that sort of lack of interest or attention span of people generally, unless you coat everything with some shiny object or pot of gold incentive, makes me sick. it seems you cannot do anything for the sake of discovery itself. everything must be "justified."<hr /></blockquote> We have a little time, no?

najab · Oct 10, 2005

>And despite the last 2 years of surface exploration and remote imaging, not the slightest sign of anything living has been found.The two rovers have covered what, 5km between them? There are many places on Earth where you could drive 10 times that distance and not see any signs of life. And remote sensing is useless for detecting microscopic life. The sharpest 'eye' in orbit around Mars has a resolution of ~10m/pixel (I think), which means that it wouldn't be able to pick out cows on Earth!None of this means that there is life on Mars, but we haven't looked closely at enough of Mars to say conclusively that there isn't.

nexium · Oct 10, 2005

Summary: Radio waves are same as on Earth's surface, except for the man-made radio waves of Earth, with some exceptions. These have little or no effect on biology, except at intensities that rarely occur except inside microwave ovens. Earth has three? times the infrared at the surface due partly to greenhouse effect. This makes Mars too cold for most kinds of life/ much of tropical Earth is too hot for some species of life. Mars averages about the same visable light (and near ultraviolet) as Earth, because negligible clouds and the thinner atmosphere offsets 40%? less visable light from the sun. This is good news for photo synthesis and solar energy. The rest of the ultraviolet spectrum is reduced by ozone and other things in Earth's atmosphere by about ten, so this harmful to life radiation is stronger on Mars. X rays and gamma rays are minor problems to life on Earth's surface. On Mars they are harmful during solar flares, sun spots and CMEs = solar mass ejection. Helium nuclii, electrons, and hydrogen nuclii = protons and some other kinds of ionized particles are about ten times more hazardous on Mars due to the very thin atmosphere and lack of magnetic field. This is likely true of the comparatively rare particles from outside our solar system, some of which arrive at nearly the speed of light. Neutrons may also be a significant hazard on the surface of Mars. Sorry there are so many kinds of radiation. Neil

vogon13 · Oct 10, 2005

There were many more small dinosaurs concurrent with the big ones. Maybe you can expound on possible DNA sequences the small dinosaurs had that conferred resistance to your hypothetical radiation. <div class="Discussion_UserSignature"> TPTB went to Dallas and all I got was Plucked !!So many people, so few recipes !!Let's clean up this stinkhole !! </div>

chew_on_this · Oct 10, 2005

The point is that we do NOT have to exclude life. No one has to prove that life does NOT exist on Mars. They simply have to show that it does. It just takes one cell. I suppose if we were looking for cells your post would make sense. But as usual, it doesn't.

jatslo · Oct 10, 2005

I don't have a clue; it was just a thought, and not one in which I would like to hold onto for very long. <img src="/images/icons/wink.gif" />

Philotas · Oct 10, 2005

New interpretations of the Viking lander data tells a different story, but that`s controversial. Not controversial, the methane-findings of Mars Express, wich overlap with the water vapour. How do you explain that? Wouldn`t the water make it more possible for life? -- The conditions on Mars is not necessarily as hostile as people want it to. Every year we find just more and more extreme extremophiles here on Earth making extraterrestial life more likely for every discovery. <div class="Discussion_UserSignature"> </div>

halcyondays · Oct 10, 2005

<<< ...the reason dinosaurs (general biology of the time period), were so large was because the Earth was less efficient at blocking harmful radiation? Meaning, there larger mass was better at absorbing radiation; they homogeneously evolved that way because of higher radiation levels. />>> In addition to Vogon's response, there were also plenty of small land mammals around the earth while the dinosaurs (large and small) dominated. Also, we have had later periods when there were far larger land mammals around than today.

paleo · Oct 10, 2005

"Has it ever occurred to you that the reason dinosaurs (general biology of the time period), were so large was because the Earth was less efficient at blocking harmful radiation? Meaning, there larger mass was better at absorbing radiation; they homogeneously evolved that way because of higher radiation levels." Hopefully any sane person will answer 'No'. Has it ever occured to jatslo that dinosaurs were big because they ate too much ice cream?

bonzelite · Oct 10, 2005

insofaras large animals, a possibility, too, is that the earth's gravity was a bit less than it is today. allowing for larger animals to proliferate. under today's gravity, creatures of such sizes as the largest dinosaurs may not have been able to walk, stand, pump blood, anything.

halcyondays · Oct 10, 2005

<<< insofaras large animals, a possibility, too, is that the earth's gravity was a bit less than it is today. allowing for larger animals to proliferate. under today's gravity, creatures of such sizes as the largest dinosaurs may not have been able to walk, stand, pump blood, anything. />>> I don't think there's any evidence that the earth's gravity has changed to any material degree in a mere 65m years (which is after all only 1.4% of the earth's entire age), and we still have some large animals around today, not least the cetaceans. There are some theories about large animal evolution, the details of which I forget for now. However, if I recall, it's something to do with the metabolic rate of an animal being lower in proportionate terms to the animal's overall surface area. So there is some efficiency gained with size, provided there is fuel for the system (ie. food), and large animals also tend to live longer than small animals. In any case, there may be climatic reasons and food reasons why there are conditions which predispose evolution to larger animals at certain eras (eg. tropical conditions across the world and large amounts of plant growth).

bonzelite · Oct 10, 2005

maybe they all injected steroids like barry bonds.

jatslo · Oct 10, 2005

If planets dissipate and decay, like everything else in the universe does, then a greater gravity is possible, which may require larger masses for circumnavigating increased pressures. Great Idea! Stevehw33 should have fun with that speculation. <img src="/images/icons/wink.gif" />

jatslo · Oct 10, 2005

Hold that thought; you may be onto something. Great Post!

Question about radiation on Mars

Leovinus

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pyoko

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