# Water on the red planet

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As far as you may know, scientists found a huge amount of water on Mars. Ive been wondering for a while if that water is contaminated with radiation because of the high level of radiation on the red planet?

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Water can’t be “contaminated with radiation”. Contamination is actual radioactive material.

Water could become theoretically be activated via neutron absorption, but where would the neutrons be coming from?

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22 minutes ago, swansont said:

Water could become theoretically be activated via neutron absorption, but where would the neutrons be coming from?

In the case of the Earth's atmosphere, they are created by:

$p^+ + p^+ \rightarrow p^+ + n^0 + \pi^+$

i.e. a highly accelerated proton ("cosmic ray") colliding with a gas molecule in the atmosphere creates a secondary pi-meson and neutron, that can be absorbed by another molecule.

It transforms Nitrogen-14 to Carbon-14:

$N^{14} + n^0 \rightarrow C^{14} + p^+$

Analogous reaction can happen in Mars or other planet atmosphere.

Edited by Sensei
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2 minutes ago, Sensei said:

In the case of the Earth's atmosphere, they are created by:

p++p+p++n0+π+

i.e. a highly accelerated proton ("cosmic ray") colliding with a gas molecule in the atmosphere creates a secondary pi-meson and neutron, that can be absorbed by another molecule.

It transforms Nitrogen-14 to Carbon-14:

N14+n0C14+p+

The (electric) charges don't balance.

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5 minutes ago, studiot said:

The (electric) charges don't balance.

???

Nitrogen has 7 protons, free neutron has 0, Carbon has 6 protons, free proton is 1. 7 = 7 as far as I can see.. isn't?

Edited by Sensei
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59 minutes ago, Sensei said:

???

Nitrogen has 7 protons, free neutron has 0, Carbon has 6 protons, free proton is 1. 7 = 7 as far as I can see.. isn't?

The equation, as written, has zero net charge (  0  + 0 = 0 ) on the left hand side but + 1 positive charge in the right hand side   ( 0 + 1 = +1 )

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18 minutes ago, studiot said:

The equation, as written, has zero net charge (  0  + 0 = 0 ) on the left hand side but + 1 positive charge in the right hand side   ( 0 + 1 = +1 )

What do you mean by net charge?  There are 7 protons on the left and 7 protons on the right, so it balances.

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Obviously once Nitrogen N-14 transmutes into Carbon C-14, it does not need anymore one of electrons which is also ejected.

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6 hours ago, Sensei said:

In the case of the Earth's atmosphere, they are created by:

p++p+p++n0+π+

i.e. a highly accelerated proton ("cosmic ray") colliding with a gas molecule in the atmosphere creates a secondary pi-meson and neutron, that can be absorbed by another molecule.

It transforms Nitrogen-14 to Carbon-14:

N14+n0C14+p+

Analogous reaction can happen in Mars or other planet atmosphere.

At a greatly reduced rate, owing to the thin atmosphere and the fact that N2 only makes up a few percent, rather than ~80%

6 hours ago, studiot said:

The (electric) charges don't balance.

It’s a nuclear reaction balance.

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11 hours ago, bearnard44 said:

As far as you may know, scientists found a huge amount of water on Mars. Ive been wondering for a while if that water is contaminated with radiation because of the high level of radiation on the red planet?

Probably is radioactive dust on/in the surface ice but underground water should be okay.

I'm thinking that as it is probably saltwater, we'll remove any contaminants at the same time as we are desalinating.

Edited by Endy0816
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2 hours ago, swansont said:

At a greatly reduced rate, owing to the thin atmosphere and the fact that N2 only makes up a few percent, rather than ~80%

I did not say N-14 is on Mars, or it is transmuted to C-14 on Mars, or any other planet. It was just an example of what happens in Earth's atmosphere due to cosmic rays.

The first reaction is universal:

$p^+ + p^+ \rightarrow p^+ + n^0 + \pi^+$

Further secondary reaction(s) are specific to planet's atmosphere.

Free neutrons are result of collisions of cosmic rays with matter. It can happen even without any atmosphere.

Edited by Sensei
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5 minutes ago, Sensei said:

I did not say N-14 is on Mars, or it is transmuted to C-14 on Mars, or any other planet. It was just an example of what happens in Earth's atmosphere due to cosmic rays.

The topic in the OP is Mars.

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4 hours ago, swansont said:

The topic in the OP is Mars.

..and I replied: if you have cosmic rays, you have some free neutrons created by them, transmuting one element into another.. and causing them to be radioactive..

16 hours ago, bearnard44 said:

As far as you may know, scientists found a huge amount of water on Mars. I`ve been wondering for a while if that water is contaminated with radiation because of the high level of radiation on the red planet?

OP, in a sloppy way, asked whether radioactive elements are created by cosmic rays and are in Marsian's water e.g. Tritium H-3 or Oxygen-19 etc.

OP should ask about C-14 too (because abundance of CO2) in Mars atmosphere..

If water exist on Mars and is irradiated by cosmic rays for billions of years, yes, it contains radioactive isotopes. The thinner atmosphere layer, the worser for water..

So the next question for scientists searching for "water on Mars" (or any other planet): is it radioactive and how much more than terrestrial.

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It is true that cosmic rays will occasionally spall neutrons off nuclei and give rise to an unstable nucleus or two.

However that's going to happen on Earth just as much as on Mars.

Since it's not a problem here, it won't be a problem there.

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10 hours ago, Sensei said:

..and I replied: if you have cosmic rays, you have some free neutrons created by them, transmuting one element into another.. and causing them to be radioactive..

OP, in a sloppy way, asked whether radioactive elements are created by cosmic rays and are in Marsian's water e.g. Tritium H-3 or Oxygen-19 etc.

OP should ask about C-14 too (because abundance of CO2) in Mars atmosphere..

Same issue, though, because C-14 is formed via the reaction you described earlier. With little nitrogen, there won’t be much C-14. The abundance if CO2 in the atmosphere is irrelevant.

10 hours ago, Sensei said:

If water exist on Mars and is irradiated by cosmic rays for billions of years, yes, it contains radioactive isotopes. The thinner atmosphere layer, the worser for water..

“Billions of years” is irrelevant, too. The half-lives of the isotopes you form tend to be very short (O-19 is less than a minute), which means they will not continue to build up - you will hit steady-state pretty quickly (all else being the same)

10 hours ago, Sensei said:

So the next question for scientists searching for "water on Mars" (or any other planet): is it radioactive and how much more than terrestrial.

As JC said, it’s not an issue here, so why would it be an issue there?

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Posted (edited)
19 hours ago, swansont said:

It’s a nuclear reaction balance.

Sensei's notation does not conform to the nuclear reaction notation I was taught.

For instance

${}_7^{14}N + {}_0^1n \to {}_6^{14}C + {}_1^1H$

Where the upper number refers to the mass number and the lower to the +ve charge number (so reckoned -ve for negative charges)

I also agee about the short half lives, carbon-14 has short one in terms of billions of years at just over 5 and a half thousand years.

Edited by studiot
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5 minutes ago, studiot said:

Sensei's notation does not conform to the nuclear reaction notation I was taught.

For instance

147N+10n146C+11H

Where the upper number refers to the mass number and the lower to the +ve charge number (so reckoned -ve for negative charges)

I’ve seen both. The atomic number is redundant information, so it’s sometimes omitted.

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