Questions tagged [gravity]
Questions regarding the attractive force which exists between any two bodies of matter.
359 questions
5
votes
0answers
63 views
Why do sun spots appear near the equator of the Sun?
I noticed on many examples sun spots are near the equator of the Sun. Why are there no sun spots closer to the poles of the Sun?
5
votes
3answers
335 views
Can two planets in an empty universe meet/be pulled together?
For this question assume that the entire universe is completely empty. The universe is not expanding or contracting, it is completely motionless.
Only two identical earths without moon are left in ...
2
votes
1answer
57 views
What would happen to the solar system if Earth's mass was removed?
This question is inspired by the "Stargate SG-1" episode "The Road Not Taken". In that story a device is used to shift the entire Earth to another dimension to defend against an attack.
I'm not ...
4
votes
1answer
72 views
Is an elliptical orbit around a black hole, or an orbit consisting of three bodies (including the black hole) possible?
If this is possible, would it then lead to an object undergoing varying time dilation (predictable variation with elliptical and random variation with three body)?
-1
votes
1answer
104 views
Can light be curved due to heavy gravitational force?
Lets suppose there is a huge planet having large amount of gravitational pull, then will the light passing through the planet get attracted towards it.
2
votes
1answer
136 views
Do falling bodies ever slow down?
I've had some discussions recently about black holes, and the issue of infalling bodies taking forever to reach the event horizon. That's essentially what Einstein said in his 1939 paper on a ...
2
votes
0answers
20 views
Change in axis of the Earth if the Moon would dissappear [closed]
I read that, if the moon would not be there or if it would dissapear or be destroyed it could cause the earth to rotate into a possible axis of 45° degrees. Because it would be missing the ...
3
votes
1answer
95 views
Are other planets' gravity measurable on Earth?
I understand that we can calculate the gravitational force other planets exert on Earth, but can it be measured?
1
vote
3answers
234 views
Why doesn't the vertical light beam get out of a black hole?
I'm asking this question as a follow-up to if light has no mass why is it affected by gravity?
Imagine you’re standing on a gedanken planet, shining a laser beam straight up into space. The light ...
4
votes
4answers
119 views
Why do nebulae turn into accretion disks but planets do not?
What are the factors that prevent planets from also turning into disks, like the stellar dust in a nebula does?
The Earth is not a perfect sphere, but rather it's squished at the poles and it bulges ...
4
votes
1answer
41 views
Largest non-hot gas giants
Excluding 'fluffy' or 'puffy' gas giants that are 'inflated by heat from their stars, what is the maximum radius of a gas giant planet. I keep reading things like "...Jupiter is 'about' as big as ...
8
votes
3answers
1k views
Gravitational acceleration inside a planet
The gravitational acceleration, g, inside the Earth generally decreases with decreasing distance to the center:
However, apparently for Jupiter, the gravitational acceleration only increases with ...
2
votes
0answers
37 views
Can eternal inflation and gravity explain dark energy?
First of all, I have absolutely no background in astronomy and physics. I just watch a lot of "i-hope-scientific" youtube channels talking about physics and astrophysics and I can kind of follow the ...
0
votes
1answer
65 views
How would humans with appropriate equipment navigate the surface of Saturn's moon Titan on foot?
Taking into account the physical characteristics of Titan (e.g. surface gravity, atmospheric pressure), what would be the most efficient method of motion for an astronaut to navigate the surface of ...
5
votes
1answer
576 views
How does gravity affect pressure under water?
How different would being under water in Europa differ from being under water on Earth? Would it be possible to dive deeper on Europa with a submarine than on Earth and by how much?
15
votes
3answers
3k views
Why don’t we feel the Earth rotating beneath us?
I’m not sure all of the details in the experiment but basically it went as follows. Someone marked their location of take off in a hot air balloon and went straight up in the air. They stayed ...
0
votes
1answer
61 views
Black hole, escape velocity, going up?
I do know nothing can escape a black hole, and I understand popsci explanation of geodesics of space-time around and inside the event horizon.
I however have some trouble with following thought ...
4
votes
2answers
92 views
Could a moon be passed from one planet's orbit to another?
Like if you had two planets that had a close orbital path could the moon be pulled away from the first planet?
2
votes
1answer
74 views
What is the smallest possible planet with same sea level atmospheric pressure as Earth? [closed]
Suppose there is a planet made of pure tungsten (a quite common and heavy element), with perfect spherical shape.
Which should be its radius so that the air pressure and ground/sea level is the same ...
1
vote
1answer
55 views
The specifics of two Earth-like worlds orbiting each other? [closed]
I'm currently looking into writing a story or two set on twin worlds, which I came to find out in my research is apparently not a new idea (Double planets?
Rocheworlds? Am I close?). But I want it ...
-1
votes
2answers
69 views
Since gravity is like an indent on a piece of paper (the space/time matrix) to a marble, can the black hole eventually suck in the matrix?
Can a black hole suck in time? People claim that if you were to put a bowling ball on a trampoline and rolled much smaller balls through the deppression, some would stay in "orbit", some would roll ...
1
vote
2answers
70 views
Is there a limit to how fast spacetime can bend/warp around an accelerating object?
If in the future a spaceship can accelerate to nearly the speed of light, will it encounter any kind of resistance/drag from the spacetime in front of it not being able to bend/warp fast enough around ...
1
vote
3answers
139 views
Could the Moon sit on the Earth?
Let say that the Earth's Moon was knocked out of orbit and landed on the Earth with some damage but not world ending. Would Earth's atmosphere envelop to include the Moon? Would the moon sink into the ...
2
votes
1answer
69 views
How dependent is Earth is with the other Planets' gravity? [duplicate]
How would the Earth be affected if the Moon was destroyed as far as our orbit around the Sun? What if Mars or Jupiter was destroyed?
1
vote
1answer
67 views
Does time dilation increase within overlapping gravitational fields?
If a spaceship was to travel to the barycenter of a binary star (the stars having identical size and mass) and come to a stop there, would the people on board this spaceship find that time is moving ...
-1
votes
1answer
60 views
Expansion ofthe Universe [duplicate]
If the universe is expanding how come Andromeda is heading for us?
In isolated spatial areas does gravity overcome universal expansion?
What is the gravitational force between us and Andromeda?
2
votes
0answers
34 views
Astrophysical Jet Size?
I am wondering about what is the estimated size of astrophysical jet that shoots out from a black hole, I don’t know if it is determined by the size of a black hole.
What would classify a black hole ...
-1
votes
1answer
80 views
Space curvature and its rotation
As I learn, the gravity is caused by the spacetime curvature. Is there any gravitational/magnetic field that really exists around the Earth, or any other planets?
Since the planets/stars rotate, does ...
4
votes
2answers
184 views
Why does earth not collide with the sun? [duplicate]
Gravity is most accurately described by the general theory of relativity (proposed by Albert Einstein in 1915) which describes gravity not as a force, but as a consequence of the curvature of ...
9
votes
1answer
2k views
Could dark matter be wrong? [duplicate]
As I understand, the evidence for dark matter is the observation of the gravitational dynamics of objects around the size of galaxies and above. They move in a way such that the equations imply there ...
11
votes
3answers
1k views
Is there any orbit at which the Roche limit can be “felt”?
Do any of the planets have a Roche limit that is strong enough to be felt by an astronaut whilst in orbit?
3
votes
1answer
51 views
How come moon's difference in thickness between sides does not create an unbalance on its mass?
I've just found out that moon's dark side is 30 miles thicker then the closer side to the Earth. So I'm wondering about moon's mass. How come it's still balanced? Supposing the far side is indeed ...
3
votes
1answer
70 views
Can gravity be amplified by other celestial bodies in its vicinity?
I`m wondering if the gravitational pull from earth that should be constant around the planet, will get amplified by a celestial body like the moon orbiting the earth?
1
vote
2answers
159 views
Universe Sandbox 2 accurate representation of gravity
I've been playing Universe Sandbox for a while now and I have never been able to make a near Earth asteroid collide with it. By "make" I mean, simulating billions of years of known, near Earth objects ...
1
vote
2answers
106 views
How does the gravity of one planet affect the velocity of other planets?
If there was a massive enough planet outside of earth's orbit to affect it, how would the earth's velocity change? I know it would be small, but would the velocity increase or decrease?
-1
votes
1answer
43 views
Could two planetesimals orbit a dense object and share an atmosphere?
Could two objects be caught into an orbit around some kind of dense object, perhaps a rogue planet. Could they share an atmosphere.
-1
votes
1answer
65 views
Physical measurements and celerity of black hole mergers?
LIGO detected a black hole merger for bh's of about 30 solar masses, with a schwartzchild radii of about 20km.
Were the gravity waves generated by masses distanced by a few microns or a few ...
5
votes
3answers
241 views
Why do neutron stars collide instead of just revolving around each other like planets revolve around the Sun?
We know about events like two neutron star colliding and resulting in a black hole, also collision of black holes, and collision of galaxies. But we never see a satellite such as a moon colliding with ...
3
votes
1answer
187 views
Are the planets in our solar system in free fall?
If I’m correct, the International Space Station is in free fall, but is moving fast enough to keep it’s position. Assuming that is true, does that mean that some/all planets orbiting the Sun are in ...
3
votes
1answer
183 views
How far out can the sun keep celestial objects revolving?
Astronomers define the Solar System as the distance under the influence of gravity from the Sun.
I read that the Oort cloud is probably the farthest object that surrounds the sun. The sphere of this ...
1
vote
0answers
33 views
Does center of gravity of Solar system influence intensity of space rays reaching earth, space dust, speed of earth rotation?
I found an interesting article, claiming very interesting things. But I cannot find any trust-worty sources confirming such bold claims. Maybe someone came across some solid proof?
1) Center of ...
1
vote
0answers
105 views
Great attractor is doing the big crunch? [closed]
Laniakea and other super clusters are moving towards shapely super cluster .
Even the Great Attractor is moving towards it. Isn't it all about the Big Crunch?
2
votes
2answers
136 views
When the asteroid hit the earth 65 mya did the earth's gravity pull change? By how much?
When the asteroid hit the earth 65 million years ago, did the earth's gravity pull change? By how much?
0
votes
0answers
57 views
Inconsistent Precession (Apsidal Rotation) Rate formulae for circular Clairaultian Orbits
TWO CLAIRAULTIAN GRAVITATIONAL FORMULAE
Wells 2011/2016 refers to two well-known patterns of centripetal acceleration which (when applied in a Euclidean-Newtonian orbital system) produce "perihelion ...
4
votes
1answer
219 views
Can a star eat a black hole?
I know there are stars much larger than the sun and that we've discovered "small" black holes, so, let's say that the Pistol Star, which is at least 80x the mass of the sun, and the smallest known ...
1
vote
2answers
188 views
Roche limit - calculation with centrifugal forces
Let's assume there is a small natural satellite oribiting a massive planet. The satellite rotates synchronously (revolution period = orbital period) on a circular orbit, both bodies are homogenous and ...
2
votes
0answers
263 views
Gravity on a right rectangular prism? [closed]
Let's assume there is a right rectangular prism floating about in space, what would the gravity be like across its 6 flat surfaces? What gravity would you experience if you set foot on the rectangular ...
0
votes
2answers
149 views
Do other planets affect the Earth?
Let say Mercury, Venus, the Moon were all in alignment between the Earth and Sun. They are all closest to each other in respective elliptical orbit. On the other side of the Sun you have the rest of ...
6
votes
1answer
92 views
Can Earth be spun like a magnet?
Could an asteroid or a rogue planet have enough magnetism and/or gravity to spin the Earth near the speed in which they are passing by Earth?
1
vote
1answer
379 views
Can you simulate artificial gravity by using an electromagnetic field?
If you create a electromagnetic field under a surface could you then create artificial gravity effect by wearing magnetized clothing and shoes?
Or could you bombard objects that you want to ...
