# RADIATION FLUX AND MARS SUPPORTING LIFE? help unit 5 physics

#1

I don't know how to explain the 2nd mark. how does the radiation flux of mars being half that of earth have any link to supporting life?
0
4 years ago
#2
(Original post by sarah99630)

I don't know how to explain the 2nd mark. how does the radiation flux of mars being half that of earth have any link to supporting life?
It's a lot to do with liquid water... google for goldilocks zone

but also the quantity of solar radiation. you probably did something on trophic levels and food pyramids in pre gcse science, the food pyramids all started with green plants using sunlight. There are some specialist organisms on earth that use geothermal energy instead of photosynthesising with sunlight iirc... but the core of mars has cooled so there is no geothermal energy supply available there.

You could say something about the flux on mars being lower but somewhat comparable to that on earth. in the outer solar system it's much weaker due to the inverse square law.
1
4 years ago
#3
(Original post by sarah99630)

I don't know how to explain the 2nd mark. how does the radiation flux of mars being half that of earth have any link to supporting life?
Someone else asked this same question a few weeks back.

The question is really asking you to understand that the flux arriving at Earth is an average and varies considerably according to season, cloud cover, ocean depth etc. i.e. compare the flux arriving at Earth (we know Earth supports life and has liquid water) with that arriving at Mars (where we know there is also water as permafrost just below the surface but also a much thinner atmosphere).

So you have to make an intelligent estimate by comparing the range of flux arriving at different places on earth, (where we know life is supported) with that average flux arriving at Mars.

For instance, on Earth, we know life exists in the oceans where the flux and light is attenuated significantly with depth. The average flux arriving in the deep ocean supports life but is still well below the average flux arriving at say, the equator, on Mars. So from an energy perspective when compared with the Earth, if there is water on Mars, then the radiation flux arriving at Mars at shallow depth, should also be capable of supporting life. But that also supposes water exists in liquid form (0 to 100 Centigrade) on Mars somewhere. You will need to make an intelligent assumption whether this is likely or not.

Also think about how the atmosphere on Earth protects life from high energy and intensity solar radiation compared with the flux arriving at Mars but also because there is virtually no protective atmosphere etc.

There is no right or wrong answer, but any answer statement you do give (yes, Mars may be able to support life, or no it probably does not support life etc.) must be justified by showing you have linked your correct factual physics knowledge as reasons to support your answer either way.

https://www.thestudentroom.co.uk/sho...770&highlight=
1
#4
(Original post by Joinedup)
It's a lot to do with liquid water... google for goldilocks zone

but also the quantity of solar radiation. you probably did something on trophic levels and food pyramids in pre gcse science, the food pyramids all started with green plants using sunlight. There are some specialist organisms on earth that use geothermal energy instead of photosynthesising with sunlight iirc... but the core of mars has cooled so there is no geothermal energy supply available there.

You could say something about the flux on mars being lower but somewhat comparable to that on earth. in the outer solar system it's much weaker due to the inverse square law.
Great explanation! thank you so much!
0
#5
(Original post by uberteknik)
Someone else asked this same question a few weeks back.

The question is really asking you to understand that the flux arriving at Earth is an average and varies considerably according to season, cloud cover, ocean depth etc. i.e. compare the flux arriving at Earth (we know Earth supports life and has liquid water) with that arriving at Mars (where we know there is also water as permafrost just below the surface but also a much thinner atmosphere).

So you have to make an intelligent estimate by comparing the range of flux arriving at different places on earth, (where we know life is supported) with that average flux arriving at Mars.

For instance, on Earth, we know life exists in the oceans where the flux and light is attenuated significantly with depth. The average flux arriving in the deep ocean supports life but is still well below the average flux arriving at say, the equator, on Mars. So from an energy perspective when compared with the Earth, if there is water on Mars, then the radiation flux arriving at Mars at shallow depth, should also be capable of supporting life. But that also supposes water exists in liquid form (0 to 100 Centigrade) on Mars somewhere. You will need to make an intelligent assumption whether this is likely or not.

Also think about how the atmosphere on Earth protects life from high energy and intensity solar radiation compared with the flux arriving at Mars but also because there is virtually no protective atmosphere etc.

There is no right or wrong answer, but any answer statement you do give (yes, Mars may be able to support life, or no it probably does not support life etc.) must be justified by showing you have linked your correct factual physics knowledge as reasons to support your answer either way.

https://www.thestudentroom.co.uk/sho...770&highlight=
Great explanation!!! thank you soo much. and also thanks for the link to the other thread
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