r/spaceporn • u/joosth3 • Oct 07 '22

The tallest mountain in the solar system, Olympus Mons on Mars. It has a height of 25 km, Mount Everest is 'only' 8.8 km tall.

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u/skullduggeryjumbo Oct 07 '22

how do they determine sea level on mars? shouldnt we count everest from sea floor level on earth to more accurately compare?

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u/Tirriss Oct 07 '22

They ship all our oceans water to mars to make their measuress, then they ship it back to earth. They usually do it at night so we dont notice it.

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u/MastaGarza Oct 07 '22

So fish get a free trip to Mars?

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u/SerratedRainbow Oct 07 '22

We don't determine "sea level" on Mars, just the mean elevation of the overall surface. That's what is referred to as the datum rather than sea level.

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u/Themountaintoadsage Oct 07 '22 edited Oct 09 '22

They determine it based on a set atmospheric density Edit: Why am I being downvoted? That’s literally how they determine Mars’ version of “sea level”. By using a specific level of atmospheric density as a baseline, they can determine elevation or depression from there. Scientists came together and chose a somewhat arbitrary number based on atmosphere density at the most common elevation, as there’s obviously no actual sea level to work with. It’s not much different than how we measure it here on Earth really, as air density at sea level is 1 atmosphere. Mars’ sea level is called Mars Datum Surface, and it’s the point of elevation where the atmospheric pressure is 6.1 Millibars, or 610 Pascals