Near the end of The Martian movie we see Mark Watney shirtless, and his body appears to be bruised. What is the cause of these marks? I thought it might be from scurvy or some other malnutrition.

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    Well, he did go through two explosions and one rapid decompression... – FuzzyBoots Oct 6 '15 at 23:13
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    Malnutrition and lack of bathing? – Joe L. Oct 6 '15 at 23:19
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    @SeanDuggan The marks OP is referring to happened after the "7 Months Later" tag. He'd certainly have healed by then. – Nerrolken Oct 9 '15 at 17:10
  • @Nerrolken: Gotcha. – FuzzyBoots Oct 9 '15 at 17:24
  • Scurvy. He's a space pirate, after all. – Crashworks Mar 4 '16 at 7:29

When Mark takes the suit off in the ship at the very end of the movie everybody complains about his body odour.

He says " I haven't had a shower in a year".

Having been in a similar situation ( with no acces to water for a long period of time ) I can tell you that his marks look a lot like something you get from not enough personal hygiene combined with a poor diet.

this this

  • Interestingly, as far as I remember, there is no mention to these lesions in the book... – heltonbiker Oct 22 '15 at 1:59
  • It's very possible it is from malnutrition and hygiene. In the book it mentions there are enough vitamins to last for a long time but this is not mentioned in the movie so I would suspect that route – Huangism Feb 26 '16 at 21:58

I was struck by the skin lesions/rash as well, and have been looking for an explanation. I suspect it had to do with prolonged exposure to radiation. The Mars atmosphere is very thin, 100 times less dense than Earth's. An astronaut wouldn't have the same protection from solar radiation that we enjoy on Earth.

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    The protection from solar radiation would come from the magnetosphere, rather than the atmosphere. Mars has a weak, bordering on non-existent magnetosphere. There are parts of Mars which have magnetism but not enough to shield the planet nor any space travellers. – heptapod Oct 7 '15 at 17:24
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    This cannot be correct. If those were the marks of radiation sickness, he would be dead within weeks, if not days. – Michael Borgwardt Oct 10 '15 at 22:48
  • Also the book handwaves radiation issues away with an argument about the HAB's canvas doing the shielding (WTF!). Not that he also stays outdoors quite a lot. – Ghanima Nov 27 '15 at 7:00
  • @MichaelBorgwardt I think he also travelled with radiating plutonium?.. – prakhar londhe Nov 27 '15 at 9:36
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    @prakharlondhe: basically the radiation is caught by the shell and converted to heat (it's alpha radiation, which is very easily shielded). In the book, it is mentioned that if the shell gets damaged, it could kill him. But my main point is that radiation sickness bad enough to leave the kind of symptoms visible in the movie is not something you recover from. Since he does recover, it could not have been radiation sickness. – Michael Borgwardt Nov 27 '15 at 9:43

He appears to have pellagra, which is due to deficiency of niacin (Vitamin B3) or the amino acid tryptophan, neither of which are present in sufficient quantity in potatoes to prevent this micronutrient deficiency.

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    Do you have any references to back this? – Joe L. Oct 10 '15 at 21:49
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    In the book Mark notes that he has an overabundance of vitamins, he's only worried about calories. – Chahk Oct 13 '15 at 20:36

Could be 'bed sores' from living in a pressure suit for as long as he was forced too. Staying outside the transport so it could charge up might make for all kinds of marks on his skin.


The lesions/rashes were shown at the same time his much thinner body was shown after 7 months or so.

This could have been due to prolonged diet of boiled potatoes without any source of Vitamin C and other vital ingredients.

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    The book specifically states he had enough vitamins for a long time. – Deer Hunter Oct 8 '15 at 16:57
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    @DeerHunter The movie generally follows the book pretty closely, but may not have on that particular point. – Wossname Oct 8 '15 at 21:19
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    Potatoes have plenty of vitamin C. One serving contains 70% of the daily value, according to google. – Nerrolken Oct 9 '15 at 17:11
  • @Nerrolken: Incidentally, probably under Weir having done his homework, potatoes are about as close as we get to a "superfood". They're missing a few complex proteins, but you can survive a long time on just potatoes and water. – FuzzyBoots Oct 9 '15 at 18:51

He broke a couple ribs due to the 12G's he experienced during the MAV ascent. Being yanked along by a tether with Beck didn't help matters.

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    The scene in which Watney appears shirtless with a skin rash and skin sores is before he makes the MAV ascent. – Praxis Oct 7 '15 at 0:21
  • He was also injured by being thrown in the airlock. – Jacob Krall Oct 7 '15 at 0:52
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    @JacobKrall - that was looong before the ascent. – Deer Hunter Oct 7 '15 at 10:02
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    @DeerHunter: the scene in question was also looong before the MAV-4 ascent, given that Mark has just finished taking a shower in the HAB - he hasn't even started the rover journey to Schiaparelli Crater yet! – Jacob Krall Oct 8 '15 at 16:35
  • @JacobKrall - ah. Okay, I stand corrected. – Deer Hunter Oct 8 '15 at 16:55

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