If Humans Were To Exist On A Planet The Size Of Jupiter, And They Were To The Same Scale As We Are With Earth, How Tall Would They Be?

[wazzock]

My mind was wandering this morning and this thought popped in to my head for no apparent reason, so thought I'd see if anyone had an answer, just out of curiosity.

[bert_h]

Maybe two to four inches high, and tortoise-shaped. For any surface-dwelling life form with our organic chemistry, no other shape could withstand the gravity. However, airborne life forms have been thought more probable by several science-fiction writers, who usually try to keep their science plausible.

[Gizmonster]

Well, Jupiter's radius is approx 11 times that of earth, so its circumference and other 2 dimensional measurements would also be 11 times greater.
So if the average size of a person on earth is approx 5' 9" - the equivalent on Jupiter would be 63' 3" (11 x 5.75) ...... jeez ...... I wouldn't want to meet one of them down a dark alley lol :P

[Gizmonster]

I'm assuming that the OP just wants a like for like comparrison, without taking into account the affects of the extreme gravitational forces on Jupiter.

[Zacs-Master]

They'd be good at basketball then.

[EDDIE51]

You have it the wrong way round Gizmonster. The higher the gravity the smaller a life form can be, bert_h has it right.

[Gizmonster]

No - I'm assuming that the OP just wants an answer that doesn't take into account gravitational forces.
I'm assuming that the OP just wants to know that if the earth was as big as Jupiter and everything else was as it is now, what size would humans be ........

[Zacs-Master]

Why would they not have evolved with super muscles and skeletal structure to withstand the gravity?

[Gizmonster]

...... I'm still giggling at your 1st post Zac :)

[Zacs-Master]

Good Giz. At least I made someone smile today. 8-))

[New Judge]

Surface gravity on Jupiter is not as massive as might be imagined. Leaving aside that it is not solid but liquid and gas, gravity of what appears to be its surface is about 2.5 times that on the Earth. Still massive enough to cause problems for the likes as us.

[Zacs-Master]

Like 'not being able to stand up' because its a gas giant. I think the OP meant a solid surface planet the SIZE of Jupiter. In fact, that's what he actually said.

[factor-fiction]

If Jupiter's radius is 11 times that of the earth (I thought it was bigger than that) then its volume will be 11x11x11 = 1331, so your volume would be 131 times the size. That's hard to envisage so think of it in terms of mass- someone having a mass of 13 stones would have a scaled-up mass of over 17000 stone.

[factor-fiction]

Keyboard missed out a digit second time around- should have said "1331 times"

[LazyGun]

It is an intriguing thought experiment - but I am not sure that you can just proportionately scale up a human being, irrespective of gravity or planetary size.

You would run into problems with the inverse-square law for a start. And then there would be a whole host of biomechanical problems to resolve.Scaled up humans would have to have significantly higher blood pressure to pump the increased volume of blood around a much larger circulatory system, not to mention the effort the issues of pumping blood back up the legs, which would take much greater effort, even if the gravity remained the same.

We wouid have to evolve a different form of haemoglobin, one with a greater affinity for O2, in order to ensure that sufficient O2 remained in circulation long enough to enrich the tissues at the extremities.

For similar reasons, the size of the lungs would need to be proportionately larger to allow for greater O2 exchange. The heart would have to pump harder and slower. More heat would be generated, so heat dissipation systems would need to be more efficient.

Greater stress on the bones and joints would mean that the bones would need to be disproportionately thicker, in order to support the weight and the mechanical stresses.

Virtually a whole new human,really - not just proportionately larger.

The tallest humans, ignoring the rather wild biblical claims, have been around 9 feer -those who suffer from acromegalic gigantism ; And a common complaint in those individuals is burst blood vessels and varicose ulcers through the high blood pressure, and this process, leading to an infection of the ulcer, can be fatal.....

[mccfluff]

you wouldn't want to proportionally scale me up, that would be worrying....

[wazzock]

Thanks for all your replies. As I said, I had no reason for wanted an answer, just a random thought. I did indeed mean just in terms of size not taking into account gravity or anything. I wasn't sure whether it would be in terms of Jupiter being 11 Earth's wide, or that it could contain 1321 Earth's, but I'm 63'3" sounds like a scary prospect, so I'll leave it at that. Thanks again.

[wazzock]

*being 63'3", not I'm*

[Gizmonster]

I think both mine and factor fiction's answers are correct.

If someone is 11 times taller, then their width and depth would also be 11 times greater (assuming that they were scaled up in proportion) - so their volume would be 1331 times greater (11 x 11 x 11) and hence their mass would be 1331 times greater .......... the mind boggles .........

[ChickPea57]

The issue with living on the "surface" of Jupiter (to the extent it has one) is not the gravity as such, but the pressure. The atmosphere is extremely deep (5,000km or so) and pressure exceeds 10 atmospheres. It's also pretty damn cold, and poisonous, and is permeated by a massive magnetic field, and full of winds far in excess of hurricane force.

The gravity will actually vary significantly with latitude, as the rapid rotation means that there is a noticeable equatorial bulge.

All in all, not prime real-estate.

[footieshorts]

...And the question did specify a planet "the size of Jupiter" , not Jupiter itself!