Suppose humanity found a rocky planet outside the solar system. It is in the habitable zone of its star, has breathable air, clean water etc. A true paradise.

Only problem is, its surface gravity double that of Earth.

Let's forget for a while that this is going to be extremely taxing on whatever colonists decide to settle there. They are going to anyway, simply because they can.

I am thinking, though, that many everyday things we use on Earth could become awkward or even dangerous to use. For example, dropping a glass of water from a table would be much more dramatic. Showering could be painful. Riding a bike down a slope would become a new radical sport.

How would the settlers adapt their equipment, appliances, toys etc. to cope with a higher gravity?

  • $\begingroup$ What sort of technology is commonplace enough to be adapted to fit their personal lives? $\endgroup$
    – Ranger
    Jul 26, 2016 at 19:26
  • $\begingroup$ @NexTerren I am thinking of people going to another planet, so their technology will be more advanced than ours. Anything that is commonplace for us then should be commonplace for them, and you can insert as much sophistication as you like. $\endgroup$ Jul 26, 2016 at 19:33
  • $\begingroup$ Build that Megastructures 05 Shellworlds - it will help to set gravity to normal one where living surface will be. Or make your tools 2 times stronger - kinetic energy of falling water glass will be just 2 times bigger then normal (hm although it's expected to break in normal gravity). Main problems will be humans, they could be reinforced with tech, without changing they human nature. $\endgroup$
    – MolbOrg
    Jul 26, 2016 at 20:49
  • $\begingroup$ @MolbOrg kinectic energy is proportional to the square of speed. Since gravity has to do with acceleration rather than speed, I think a drop from a given height at 2G will actually cause an impact more than four times as strong as it would on Earth. $\endgroup$ Jul 26, 2016 at 22:30
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    $\begingroup$ @MolbOrg you are right. I stand corrected. Thanks :) $\endgroup$ Jul 26, 2016 at 23:42

2 Answers 2


A number of complications come from 2x gravity.

First any fall would be considerably more deadly. My (at the time) 60-year-old mother broke her wrist fairly badly by simply falling down in a Home Depot parking lot. She has no medical conditions that impair the strength of her bones; that's just life. 2x the gravity would likely increase this threat. I assume some sort of soft exoskeleton would be normal for day-to-day, and a more robust hard suit when anything physical was involved.

Simply standing up and walking would be challenging, if not impossible. A 200 pound athletic man would suddenly be lugging around 400 pounds, and would not be able to run (likely at all) or even travel very far distances. For this reason the exoskeleton likely needs to be upgraded with robotics to take pressure off the muscles.

Blood pressure is also an issue. To quote a source:

Under normal conditions, your body must maintain 22 millimeters of mercury blood pressure to get blood from your heart to your brain. Each additional +Gz (blood flows from the head to the feet) that a person experiences multiplies that requirement: The body has to muster double that at 2g, triple that at 3g, and so on until they hit around 4 or 5 G's, at which point most folks will pass out due to oxygen starvation because all the blood stays in their feet.

This condition is known as G-LOC (G-induced loss of consciousness). Fighter pilots, with the aid of flight suits packed with air bladders that force blood out of the lower extremities as well as specialized breathing and tension techniques, can be trained to withstand up to 9 +Gz.

So the exoskeleton also should provide external pressure like a flight suit to allow blood pressure to be maintained.

Further still the increase in atmospheric pressure (from the increase in gravity) would make it harder to breathe in and out, while simultaneously forcing extra gasses in your bloodstream including oxygen and less-than-ideal other gasses included. We could negate both of these issues by suiting entirely up with oxygen tanks and a sealed mask, or we'll have to accept the drudgery of simply breathing and carefully terraform the atmosphere to an ideal composition.

Likely buildings will be built around asinine safety with railing common, stairs rare, and most floors designed to provide traction.

Transportation costs will be significantly more, and flight will be expensive enough that most long-range transportation will depend on railcars designed to avoid frictional costs.

Chairs will likely be reclined to be more comfortable, since the human body is designed to handle Earth's gravity, not sitting up in 2x, and even with the exosuits it will likely still be more comfortable to simply not avoid fighting gravity as much as possible.

The people will likely be unusually muscular even in ways that you normally would not expect (for example, muscle builders don't exercise blinking, but in this world every blink rips down muscles considerably more and the body will respond to try to build them back up stronger).

Toys will likely be far less physical-activity focused with again a concern for safety.

Cooking will be changed since the boiling point of water will be considerably higher, and any chemical reaction to add air to food (such as yeast causing bread to rise) will fantastically fail, most likely, producing dense food.

Most plants from Earth simply won't survive; as plants depend on osmosis to draw water up, they depend on osmosis being stronger than the force of Earth's gravity. In a 2x gravity world this likely will no longer be the case. Thus if this new world doesn't come with plants, the colonists will likely have to depend on plantstuff for food to be shipped to them from off world.

Credit to @DaaaahWoosh for some of the ideas.

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    $\begingroup$ I can't upvote you right now because I've reached my daily votes. I'd like to add one interesting thing here though: earlier today I asked another question: Slow Killing Atmosphere, about what kind of atmosphere would take more than a day to kill a person, delivering a slow but sure death. Your description of the effect a higher gravity would have in the atmosphere gave me some ideas for that! $\endgroup$ Jul 26, 2016 at 20:05
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    $\begingroup$ A lot more stuff would be done lying down. Offices would not have desks, but couches. Vehicles would have beds, rather than seats. Clothing and manners would adapt to this, in ways that would seem very strange to people who lived in 1G. $\endgroup$ Jul 26, 2016 at 20:54

Remember, after the first few generations, the colonists and whatever species they bring will have acclimatized to the new gravity. You'd expect the first generation born there to develop denser bones than their parents, have stronger hearts and so forth. The first set of colonists might simply stay on floating platforms half the planet's radius away from the surface, with only the fittest young adults allowed onto the surface. They'd need to spend time terraforming the surface anyway to make it habitable, before they can actually set up shop, so why not use this time to ensure the next generation can survive without technological support. This could also be sped up with genetically engineering humans, plants and animals to be physically more robust. Or shorter.


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