Can you fall off the moon

The simplest would be defining some arbitrary impact velocity that is at the limit of being fatal, and we then consider everything else surface properties, subject's physique, We can also neglect air resistance to make it simpler, since we're more interested in a safe height to jump off on the Moon, than that on the Earth.

Plus air resistance at such small heights wouldn't change our results much anyway. At Earth's mean sea-level surface gravitational acceleration 9. I'm cheating by using an online free fall and constant acceleration calculator , but the maths for a free fall without air resistance go as follows:. We can derive everything else we need from these two equations, let me know if you require a more detailed answer in this part. Moon's average surface gravity acceleration is 1.

Edit to add : Both these last impact velocities and mph are over So if we accept that a human can survive an impact at given velocities and mph , Moon's gravity isn't sufficient to counteract atmospheric drag of 1 atmospheric pressure to such speeds to kill you on impact. In reality, you'd then have to deal with the heat released during atmospheric reentry beyond terminal velocity, which becomes a different question altogether.

And it would of course be unfeasible, the Moon doesn't have sufficient gravity and magnetic field to sustain Earth-like atmospheric pressure. Solution to calculate lunar terminal velocity, with a known terminal velocity of the same object and same atmospheric density on Earth:. For a belly-to-earth i. On the Moon, using our conversion value of 0. I would still argue that this is not survivable due to lack of vegetation and unweathered sharp terrain on the Moon, but it is a food for thought.

For a lbs, this "only" amounts to an impact force of 1, Newtons. With some luck and landing into a deep pocket of lunar dust and no larger boulders in the way, it might be survivable. Still, that's in a face down position, so most likely not. Another thought though, that our subjects are acrobats that would probably achieve jumps of such heights with their own power. So they would first have to work against the same gravitational acceleration that will later try to kill them on impact.

Point being, that if you can't jump on Earth to heights that would be fatal to land from, you won't be able to do that on the Moon either. Of course, bone density loss usually comes with muscle atrophy, so the ability to jump as high might decrease, too.

Going away from the scientific answers, and more towards the psychological answers, I'd like to approach how one makes a mistake bad enough to break a bone. The first step involves getting enough energy to break the bone with a fall in the first place. The body should naturally do a reasonable job of balancing the muscle strength needed to do tasks against the bone strength needed to oppose the muscles. This is why you see little fear of broken bones on the ISS -- their muscles and bones atrophy in harmony.

However, when they come back to earth, their muscles are forced to push themselves to the limit to fight gravity, and the bones haven't been given an opportunity to catch up. Think similar to forgetting to stretch before physical activity.

So to get the energy to break your bones, you'd probably have to rely on something other than jumping. A tall fall could do it, just like on earth only taller. This is where the psychology comes in. If you have not had enough time to get used to low gravity rules, your brain may not realize it is in trouble until too late. You may get cocky, and think you can take the 1km fall because the m one wasn't so bad.

The brain has a lot of safeguards to prevent us from hurting ourselves. The most likely culprit would be mass vs weight. If someone had not gotten used to low gravity such as an Earthlander visiting the Moon , they may drastically underestimate the inertia of an object because it "doesn't weigh much.

This has happened at least once in our spacewalks. An engineer designed a procedure that involved powering down a spinning dish and then stopping it to do maintenance. The earthbound engineer accidentally assumed that the dish would have little inertia, because they were weightless. The spacewalker found it was virtually impossible to stop the disk. They ended up finding a smooth ring on the dish, and appyling friction for several minutes to get the rotational rate down to where the spacewalker had the muscle and bone to actually stop the rotational inertia of the disk.

I'm starting to sound like a broken record, but I agree with Tildal's post yet again. There is one more thing I would add that concerns an Earth native who recently travels to the Moon. Jumping ability comes from strength in muscles and tendons, while bones support weight.

Good landings come from apropriate training, coordination, etc. As a counter point, one who just came from Earth's higher grav might be able to jump very high on natural strength alone and not be able to land as easily as they jumped.

The more dense bones might be able to take the force, but I am concerned with the ability of the tissues to absorb the shock and take the damage. When you combine the speeds that Tildal writes about with a solid ground and number of factors could contribute to injury. It could be possible that an untrained individual may not be able to react quickly enough to the increase in speed or not be able to accurately estimate the distance to the ground much like when jumping out of a plane on the Earth, the trees come up rather quickly.

Any number of issues could arrise that could cause serious damage. I don't see people dying per se, but with speed and a solid ground, one could hurt themselves much more easily than they would on Earth with a similar jump.

In relation to the book great book btw , these acrobats are trained and Lunar natives or at least they have been on the Moon long enough to become skilled with movement with the lower gravity. It is possible with the aid of some suspension of disbelief that they are able to react more quickly, and perform movements that help mitigate or disperse any force applied, much like a parachute landing fall plf can save someone from falling a great height by rolling the force in a different direction.

This is ignoring friction, which is certainly valid on the Moon, and valid for moderate yet fatal heights on Earth. The damage done on hitting the ground is mostly a function of the velocity of impact, so whatever height makes you uncomfortable on the Earth, six times that heigh should make you uncomfortable on the Moon. First of all, let's ask how far does a fall from Earth have to be to have injury? For simplicity, I'm going to assume a health middle aged adult, the typical range for astronauts.

Looking around, the height of serious injury on the Earth appears to be 7 m, or something relatively close to that. In fact, the height might be even lower. I'm also going to assume that the person was well conditioned.

We know that bone mass is lost in zero gravity, and I'm going to assume that the person falling still have an Earth bone mass. As bone mass is lost, the chance of injury increases dramatically. So, a 7 m fall from Earth will end up with a velocity of about What distance is required to have that speed on the moon?

The answer is about 43 meters. Of course, that's the serious injury level, and in fact the fall distance might well be less than that, as you lose bone mass from being in low gravity for so long. But this should be a good starting point at least. As on Earth, it really depends how you land. High-jumpers land on crash mats, therefore it seems reasonable to suppose that on Earth it's possible to jump high enough to sustain injuries on landing, anyway if you choose to land on the back of your shoulders and head.

I certainly would not choose to leap head-first at the ground, I reckon that would mess me up ;-. As others have pointed out, the strength of gravity doesn't make a difference here, you land with whatever speed you can jump at, so the same would apply on the Moon.

You can't jump so high that you'll injure yourself if you land well , because humans are well-equipped to jump and land. Our legs can handle take-off speed in reverse. Any of our potential ancestors whose legs couldn't do that, probably broke their legs early and never reproduced It might be harder to jump into the air and land on your feet on the Moon than it is on Earth.

Aside from being unfamiliar with low gravity, the jump takes longer 6 times longer , so you have to jump more accurately to avoid rotating significantly in the air.

So take it a bit easy before you go bounding around the place, your risk of landing on your head is increased compared with Earth. What about heights we can't jump to? On earth, a 4m fall onto something hard is pretty nasty if you don't land properly, and it's difficult-ish to land properly. The only inaccuracy I can see is at Venus, which has such a dense atmosphere that it would make jumping harder than it looks in the example. Not only does a planet's gravity affect how high you can jump but also the rate of your fall.

With less gravity tugging at your body, you descend more slowly on the moon compared to the Earth or Jupiter. The strength of gravity you experience on a planet or moon also depends upon its density — how tightly packed the material is.

If you had two planets with identical masses, but one was smaller and therefore denser , you would weigh more on the smaller, denser planet. In fact, if you compressed the Earth into a sphere just 0. Shortly before that moment, if you could somehow stand on the rapidly shrinking Earth, you would weigh billions of tons. But because the mass of the Earth would be unchanged, the moon would still revolve the marble-sized planet just like always as if nothing had happened.

Weird, right? The sun is by far the most massive object in the solar system, weighty enough to keep all the planets in place. But its gravity, like that of all objects, decreases with distance. The closer you are to a massive object the more you feel it's pull.

The sun has a much tighter grip on Mercury, the closest planet, for instance compared to a comet at the edge of the solar system.

The sun powerful gravity, 27 times greater than that on Earth, holds the planets in orbit. Not to scale. Gravity is everywhere. It keeps us anchored to the ground. The pull of the moon and sun creates the tides. Clouds of gas and dust called nebulae collapse to form stars and planets under its grip.

But beware: when you come down after your record-breaking jump, the landing will feel just as hard as it does on Earth.

The fastest jumping human being ever was Javier Sotomayor, who reached a speed of 7 metres per second, and a height of 2. The speed at which you jump does not depend on the strength of gravity — it depends on your muscle strength and skill.

What about fleas? They would be able to jump well into space, surely? They do jump many more times their own height, of course — but then, they are really tiny. The highest jumping animal in the world is the white-tailed jackrabbit. They can jump over six metres in the air, and would certainly get a speeding ticket if caught jumping in town. On the moon, a white-tailed jackrabbit would easily jump over a ten-storey flat — but still not shoot off into space. People would love to go back to the moon.

If they get serious about it, it will happen. You can:. Here are some more Curious Kids articles, written by academic experts:.