All Questions
87
questions
154
votes
14
answers
58k
views
How do I explain to a six year old why people on the other side of the Earth don't fall off? [closed]
Today a friend's six year old sister asked me the question "why don't people on the other side of the earth fall off?". I tried to explain that the Earth is a huge sphere and there's a special force ...
- 1,531
39
votes
5
answers
34k
views
Would you be weightless at the center of the Earth?
If you could travel to the center of the Earth (or any planet), would you be weightless there?
- 543
16
votes
8
answers
11k
views
How do stars from far away affect Earth?
I know that we obviously get light (or we wouldn't be able to see them), but are there any other ways that they affect Earth and maybe just our solar system in general?
- 341
14
votes
4
answers
2k
views
What is the general relativity explanation for why objects at the center of the Earth are weightless?
The idea that as you move through the earth you get a symmetric cancelling of gravitational acceleration which approaches zero acceleration due to gravity at the center of the earth makes a lot of ...
- 1,039
13
votes
2
answers
2k
views
Where did the energy released due to gravitational binding energy of the Earth go?
The gravitational binding energy of the Earth is $2×10^{32} J $, so the same amount of energy must have been released during the Earth's history.
According to this and this, the current internal ...
- 3,916
10
votes
9
answers
4k
views
Why and when can the Earth be considered an inertial reference frame?
The question has been asked (e.g., here and here), but I would like to get a more definitive and mathematically formal answer.
The Earth rotates around its axis, around the Sun, and participates in ...
- 60.3k
10
votes
3
answers
226
views
How much additional light does Earth receive from the Sun due to Earth's gravitational field?
I was reading about how gravity affects light, and that got me wondering how much additional light is collected by the Sun due to the Earth's gravitational field.
Is it a significant amount of light (...
- 203
8
votes
7
answers
10k
views
Why doesn't Einstein's general theory of relativity seem to work on Earth?
I am new to physics and I have learned a little bit about gravity from Einstein's perspective. The gist is that heavy objects create curvature of spacetime, and free-falling objects move on the ...
- 253
7
votes
2
answers
1k
views
Does Earth experience any significant, measurable time dilation at perihelion?
Is there any measurable time dilation when Earth reaches perihelion? Can we measure such a phenomena relative to the motion of the outer planets?
- 79
5
votes
5
answers
4k
views
Why doesn't the Earth release you as soon as you escape it?
I've always wondered, that since the Earth is moving at a very fast velocity around the Sun, why is it that when astronauts leave the Earth, the Earth doesn't immediately move away from them at ...
- 1,158
5
votes
4
answers
8k
views
Could we make a trebuchet that could launch objects to a stable orbit?
Inspired by this xkcd, which calculated the energy requirements for accelerating individual humans to escape velocity (regardless of consideration for what that would do to your organs), I am ...
- 3,241
5
votes
5
answers
1k
views
Gravity is not a force - how does "accelerating up" work for the entire earth? [duplicate]
So this question has been bothering me for several days now. I've seen many YouTube videos on how "Gravity is not a Force", but no one seems to offer a simple explanation on how does this &...
- 183
5
votes
3
answers
572
views
Does the conversion of crude oil to greenhouse gases have any measurable effect on earth's gravitational pull?
Oil underground is much denser than greenhouse gas in the atmosphere.
Does the conversion in anyway effect the gravitational force from earth.
- 157
5
votes
1
answer
2k
views
If the Moon had gravity as strong as the Earth's, and a magnetic field, could it have supported life?
If the Moon had gravity as strong as Earth's, and a magnetic field, could it have supported life? Because if the Moon had as much gravity as Earth, it could have retained more water than is present ...
- 163
5
votes
1
answer
471
views
Could the Earth be ejected when the sun burns out?
My younger brother came home from school today and told us at the dinner table that when the sun burns out the Earth could be ejected from its orbit. Skeptical, I asked his source. He quoted his ...
- 184