54 votes
Accepted

Does gravity increase the closer to the core you get?

The below figure, taken from Wikipedia shows a model of the free fall acceleration, i.e., 'gravity'. The left-most point corresponds to the center of the Earth; then further right at $6.3\cdot1000$ km ...
Erik's user avatar
  • 1,999
37 votes

What is the pressure at the center of the Earth?

It is the pressure gradient that is proportional to the local gravitational force. When that force is integrated over a distance, the pressure gradient is integrated to accumulate a total pressure. ...
Oscar Lanzi's user avatar
  • 3,831
24 votes
Accepted

What is the fastest the Earth has ever spun?

The speed of rotation of Earth is controlled by its angular momentum. And the conservation of angular momentum is a very serious law of physics (perhaps even stricter than conservation of mass). So in ...
Camilo Rada's user avatar
  • 17.7k
22 votes
Accepted

Does gravity differ from place to place on Earth

There is an entire field of Geophysics called gravimetry dedicated to measuring the magnitude of the gravitational field. First, we should distinguish between weight (a force) and gravity (an ...
arkaia's user avatar
  • 15.4k
19 votes
Accepted

Are we experiencing lower level of gravity now compared to past?

Earth's radius is about 6400 kilometres. That's 6400000 metres. Let's say that you have a mound 20 metres high, burying an older settlement. Your new "radius" is now 6400020 metres. Let's say that $g ...
Gimelist's user avatar
  • 23.1k
15 votes
Accepted

Hudson Bay Has Low Gravity?

Gravitational acceleration does vary. It tends to be strongest at the poles and weakest at the equator, this is due to the oblate shape of the Earth which means that at the Equator you are further ...
James K's user avatar
  • 797
13 votes

What is the pressure at the center of the Earth?

The previous answers do a fine job already. But I'll try to add a simple thought experiment. Imagine three objects floating in space, clumping together by gravity: ...
stippi's user avatar
  • 231
13 votes

How is the atmosphere expanding in all directions if Gravity is holding the atmosphere down to earth?

A couple thought experiments up front: If you breathe on a cold day, the air doesn't rush up, despite the vacuum of space above it. Why? It's not just because of its own gravity... but because of ...
JeopardyTempest's user avatar
11 votes

Variations in Gravity over Time

Is there any consensus about the conjecture that gravitational force on Earth may have changed significantly over geological time; No, Earth's gravity did not change significantly over time. Yes, ...
Gimelist's user avatar
  • 23.1k
11 votes

Hudson Bay Has Low Gravity?

The link you give seems largely plausible about the cause of the anomaly in that area: a 2007 study found that now-melted glaciers were to blame. The ice that once covered the area during the last ...
Steve Linton's user avatar
10 votes

Does gravity differ from place to place on Earth

The weight that an object with a constant mass experiences on different parts of the Earth's surface will be slightly different for different locations, largely dependent on the height above sea level ...
Fred's user avatar
  • 24.7k
10 votes
Accepted

If Earth had rings would gravity exerted by Earth decrease?

Rings wouldn't decrease the gravity much, but the exact amount would depend on the exact geometry of the rings. One reason is that the gravity of one side of the ring would partially cancel the ...
Camilo Rada's user avatar
  • 17.7k
9 votes

What is the pressure at the center of the Earth?

Pressure at the center of the earth is non-zero. You're correct that there's no gravitational force at the center of the earth, but that doesn't mean pressure is zero - the pressure comes from the ...
Nuclear Hoagie's user avatar
8 votes
Accepted

Why doesn't Wolfram Alpha show low gravitational acceleration for the Hudson Bay?

Wolfram Alpha reports values between 9.78 and 9.88 m/s2 depending on the location, which is odd because it should stay within the range 9.76 - 9.83 all over the world. It also seems to be using the ...
FSimardGIS's user avatar
8 votes

Does gravity differ from place to place on Earth

To add to the previous answer the gravity will vary locally due to the density of the rocks (or other materials) in the area. Gravity meters are used in mineral exploration to find dense rock types ...
haresfur's user avatar
  • 4,419
8 votes
Accepted

How high is too high for hydrogen to rise?

I had a similar question, and then I learned that at the molecular level it is diffusion what dominates, that means that despite Hydrogen is lighter, it won't rise to the top of the atmosphere. ...
Camilo Rada's user avatar
  • 17.7k
7 votes
Accepted

Why does the moon orbit the earth and not the sun instead?

The moon does orbit the sun but it also orbits the earth. But your assertion that the earth's gravity is weaker than the sun's is not universally true. If the sun's gravitational pull were greater ...
jwh20's user avatar
  • 186
7 votes

How is the atmosphere expanding in all directions if Gravity is holding the atmosphere down to earth?

The Earth's atmosphere is held in place because it is more or less in hydrostatic equilibrium, where the pressure that would buoy it upward were it not for gravitation is in balance with the Earth's ...
David Hammen's user avatar
  • 23.6k
7 votes

How is the atmosphere expanding in all directions if Gravity is holding the atmosphere down to earth?

However, observable reality shows us that the atmosphere expands in all directions as it fills any and all available volume A very close measurement will reveal that in the presence of gravity the ...
Kevin Martin's user avatar
6 votes
Accepted

A balloon falling from space?

You cannot leave "temperature outside", as temperature is the key factor to know if the balloon would pop or not. Let's set up some assumptions about the problem so we can calculate something: The ...
Camilo Rada's user avatar
  • 17.7k
6 votes

Does gravity increase the closer to the core you get?

This is a companion answer to both Erik's and tfb's answers. tfb's answer assumes a uniform density throughout the Earth. This is highly inaccurate. Not to disparage tfb's answer; I've run across ...
David Hammen's user avatar
  • 23.6k
6 votes

How to make a Python function return the Moon's gravitational force (acceleration) to calculate orbits?

From my understanding, it should be possible to follow a similar procedure as what is done for calculating the gradient of gravity potential for the Earth (ignoring the potential corrections due to ...
Rafa's user avatar
  • 233
5 votes

Realtime planetary gravity maps?

For sure this is not available. To create those maps takes several dozens Earth orbits by GOCE (one orbit ~90 minutes) and possibly many more to bring up the signal to noise Which gravitational ...
AtmosphericPrisonEscape's user avatar
5 votes
Accepted

Compute direction of gravity vector

First, a distinction between "gravity" and "gravitation" as used in geophysics. "Gravitation" pertains to Newton's law of gravitation. (Nobody uses general relativity to ...
David Hammen's user avatar
  • 23.6k
5 votes
Accepted

What does the degree and order of Spherical Harmonics mean?

Citing from Wikipedia: $Y_l^m$ is called a spherical harmonic function of degree $l$ and order $m$. If we take the real part of the spherical harmonics only, there is a nice visual explanation for ...
Joscha Fregin's user avatar
5 votes

Are we experiencing lower level of gravity now compared to past?

To address your original concern, no, the fact that there are buildings underground does NOT mean that the surface of the earth is higher than in the past. What is actually happening is that these ...
PMar's user avatar
  • 51
5 votes

How is the atmosphere expanding in all directions if Gravity is holding the atmosphere down to earth?

In the radial direction (upwards), the atmosphere is very close to hydrostatic balance, and allows only very small fluctuations in velocity (Mach number <0.1%). In the horizontal direction the ...
AtmosphericPrisonEscape's user avatar
4 votes
Accepted

Plate Tectonics vs Gravity for Creating Highs and Lows

I think this question is less intuitively obvious than it appears. and I like @Universal_learner 's answer. I thought I'd give a different approach to the question. Earth is the only object in the ...
userLTK's user avatar
  • 5,857

Only top scored, non community-wiki answers of a minimum length are eligible