Is it possible to build an atmosphere on Mars without an ozone layer? What would trap the gas? Also what is an ozone layer made of?

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    $\begingroup$ Come on, doing a bit of homework won't hurt you. It even helps you spell ozone correctly. $\endgroup$
    – user10509
    Commented Sep 28, 2016 at 12:35
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    $\begingroup$ No need to be rude about it. Point them in the right direction and move on. The user's research could have been hindered by the fact that they were spelling things incorrectly, or by any of several other potential reasons. $\endgroup$
    – duzzy
    Commented Sep 28, 2016 at 15:54
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    $\begingroup$ "what is an ozone layer made of?" – Umm, ozone? $\endgroup$ Commented Sep 29, 2016 at 13:09
  • $\begingroup$ A planet needs an atmosphere with some oxygen content to form an ozone layer. Ozone is just a molecule of three oxygen atoms instead of only two. $\endgroup$
    – Uwe
    Commented Mar 28, 2020 at 16:37

2 Answers 2


The ozone layer contains more ozone (O3) than most of the remainder of the atmosphere. It absorbs a lot of UV radiation.

An ozone layer is not required to maintain an atmosphere. All gases in the atmosphere are trapped by gravity only.

If you build a human-livable atmosphere on Mars, the oxygen in that atmosphere will automatically start creating an ozone layer.

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    $\begingroup$ Building an atmosphere without a magnetic field is another matter, though. $\endgroup$ Commented Sep 28, 2016 at 15:30
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    $\begingroup$ @Rikki-Tikki-Tavi: Nah, only maintaining it over millions of years is a problem. $\endgroup$ Commented Sep 28, 2016 at 21:40

No, an ozone layer is not a requirement but it wouldn't hurt anyway if one wants to terraform Mars. Mars would need a strong magnetosphere instead and/or a higher mass/gravity to hold a 1 atm like atmosphere.


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