So, I was reading this article about how difficult it would be for any alien race to escape an exoplanet with about 10 times the mass of Earth.

It states they probably would even lack satellites. Taking into account a planet like the one in the example, where "escaping" the planet or even putting up satellites would be impossible, how feasible would be the existance of a humanoid race, like humans, and how close to our appearance could they get?

Usually one would think they might look like DnD's dwarves due to the gravity being higher, is that a must or is there a way for their bodies to be more similar to our human stature and bulk?

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    $\begingroup$ I think it needs to be clarified that 10 times mass does not mean 10 times gravity. In the article, surface gravity for the sample planet is estimated at about 2.4g, which is not that bad. $\endgroup$
    – Alexander
    Commented Apr 23, 2018 at 21:23
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    $\begingroup$ higher oxygen environments mean larger animals, that could compensate for gravity $\endgroup$ Commented Apr 24, 2018 at 0:11
  • $\begingroup$ 10 times the mass of the earth doesn't say much about it's gravitational field on the surface and up to orbit heights. You also need the density. $\endgroup$
    – Fl.pf.
    Commented Apr 25, 2018 at 11:38

3 Answers 3


10 times the mass of Earth? I don't think there'd be much in the way of terrestrial life there at all, aside from ground cover. That's a lot of weight to lift up, and biologically speaking it's just not feasible. The most you'd get is probably some short, squat plants, or things like plants.

However, I'm going to make one assumption: this planet has oceans. Liquid water oceans to boot - maybe that's Earthling chauvinism, but I'm doing it anyway. And in that case, there would be a lot of life. Consider the kind of pressure exerted by the deep sea on our planet - we get a lot of weird things seen in deep oceans. This planet would have ALL its life like that, except without the lack of visible light. Very few bony animals, lots of things like squid or sponges or tube worms. Actually, those squid things are the most promising candidate for intelligent life - considering how smart our octopuses and cuttlefish are, it's not too far a stretch to assume that if intelligent life were to form on our hypothetical heavy water world, it'd resemble them. And if we assume our squid could have two long tentacles and two medium tentacles plus a lot of short tentacles, and if you squint really hard, they could look humanoid. So I guess there's your answer - "humanoid" life on that planet would be squids.

...I had to work really, really hard not to make a Splatoon joke here.


High-G environments arent condusive to tall creatures. In the Marines we had to specifically re-learn how to fall down because in full gear your full weight can be pushing 375 to 400 pounds and its really easy to seriously injure yourself by just falling over. On a planet with 10 times the gravity I would weigh in at almost 2000 pounds. My diaphragm wouldnt be able to inflate my lungs, my blood would pool in my feet instead of circulating, falling down would be like getting hit by a truck but that is irrelevant because my body would basically collapse under its own weight into a mushy puddle before I could fall down anyways.

Humanoid body structure is not suited to high G at all. To give you an idea of how crazy high G can get you must realise that on a planet with 10 times the gravity of earth an object dropped from 1 meter would be moving at 219 miles per hour by the time it hit the ground.

  • $\begingroup$ Ouch. Even though it's not 10G's for 10x mass, the points are well taken. Sounds like a totally different biological system needs to be invented for said planetary types. $\endgroup$
    – user39523
    Commented Apr 24, 2018 at 2:29
  • $\begingroup$ Some low to the ground, slow moving, deliberate, and probably horizontally oriented rather than vertically. On a high G world rather than organisms having growth strategies revolving around vertical growth it would instead be focused on growing outward. $\endgroup$
    – TCAT117
    Commented Apr 24, 2018 at 3:23
  • $\begingroup$ its not 10G, or even close to that. 2.4G is something completely different. Everything would be smaller, but there would still be vertical life.. $\endgroup$
    – Fl.pf.
    Commented Apr 25, 2018 at 11:37

With that mass planet would have to be less dense to support humanoids... but its possible. I believe you can go to about 2g safely maybe even less (mind you there might be issues with magnetosphere due to less iron in core but its hard to calculate). This humanoids would be much more stocky and culture would be different since you tire a lot more there. Biggest change would be to big animals on the surface. Legs like elephants or dinos and such. Plants will be shorter. Carnivores would probably depend more on traps than chasing and so on and on. There would also be more water on such planet.


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