So how close can one get to Jupiter before the gravity exceeds 1G? Inside the atmosphere?
Should be the square root of the ratio of Jupiter’s Mass over Earth’s mass multiplied by the radius of earth --> 1.6r[sub]jupiter[/sub] (112,313 km). That’s about the distance Amalthea orbits.
Of course, if you’re “getting close to” Jupiter, you’re probably doing it along some orbit, which makes the local acceleration due to gravity mostly irrelevant for passengers aboard the spaceship. For comparison, Earth’s gravity is still about 85% of its surface value, at the height of the International Space Station.
Well that or freefall into Jupiter, but again unless in the atmosphere the passengers are not going to feel the gravity.
I don’t know if the right term is “hovering” or the Jovian equivalent of geosynchronous orbit, but assuming you are stationary or nearly so relative to Jupiter’s center of mass. I.e. not in free fall.
Regards,
Shodan
Freefall directly in is a kind of orbit.
IIRC at the top of Jupiter’s atmosphere (however they define something without a definite edge) the “surface” gravity is around 2.5G.
Basically, the “surface” is what looks like the surface. The same standard is used for stars.
And for anyone wondering how it can be so low, gravity depends not just on mass, but radius, and Jupiter’s radius is a lot bigger than Earth’s.
But it wouldn’t look like “the surface” if you were at it.
And Jupiter is less than a quarter the density of Earth.
So the sci-fi stories I’ve read of folks using airships to live in Jupiter’s atmosphere is not possible? Unless those folks are OK with 2.5 Gs?
I think you should be more concerned about being crushed by Jupiter’s atmospheric pressure than dealing with its gravity.
I think a close, very rapid orbit just outside its atmosphere would be your best bet for safe exploration.
What about all the lethal radiation? Surely hanging around Jupiter can’t be that good for your health.
Good call. You’d have to be outside its magnetosphere which, according to the specs, extends something like 3,000,000 KMs into space.
A satellite in geostationary orbit remains in position above a fixed point on the equator of the Earth in a circular orbit. A synchronous orbit is one that has an orbital period which is the same as the rotation rate of the body, and thus, passes over the same point each day; a stationary orbit can be considered the trival case of the synchronous orbit. Since Jupiter does not have a solid crust the rotation rate varies with latitude and depth but equator of Jupiter rotates in about a 10 hour period, so a stationary-like orbit would be very fast and low, a scant 19,200 km above the surface.
An orbit, by the way, is “free fall” by definition; that being that only gravity is operating on an object. In the case of a stable orbit, the object is falling so fast that it literally falls above the horizon. That it appears stationary in an observer’s frame of reference is irrelevent; what matters is that it follows a geodesic curve that makes a closed, non-intersecting path around the object.
There are many reasons why it would not be desireable to live in or around Jupiter, including the charged particle environment, high magnetosphere, charged plasma from Io spraying everywhere, and having to see a giant staring red eye (or anus, depending on how you think of it) every time you look through a viewing portal. Basically, Jupiter is the Jersey Shore of planets.
Saturn has rings, better moons (including the only moon with a significant atmosphere and surface hydrocarbons), and is generally just a better neighborhood to hang around in. It is almost twice as far from Earth orbit at Jupiter, but if you’re going out that far into the black anyway, you might as well make the destination worth the effort.
Stranger
Heavy, man.
Check out the 1942 Isaac Asimov short story “Victory Unintentional” for an interesting - and funny - look at a robotic mission to Jupiter.
I’m so adding Io to the list of Jovian moons I’m not attempting.
There is some depth within Jupiter where the gravity is 1G, because the gravity of the mass above cancels out the gravity of the mass below, but I don’t know what depth that would be, and if it is before the “real” surface below the clouds, but wherever it is, it would not be a pleasant neighborhood.
Nobody knows of any “real surface” within Jupiter. There probably is one, but it’d be pretty deep down.
Any chance of it being liquid?
There’s probably liquid hydrogen.