Earth is the planet on which we live, the 3rd planet from the Sun. Questions using this tag should be about Earth the planet and not Earth-like planets nor earth, as in dirt or soil.

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11
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2answers
847 views

How much does the curvature of space change the volume of Earth by?

If we assume space is flat the volume of Earth is: $$ V = \frac{4 \pi R^3}{3} = \frac{4 \pi (6378.1 km)^3}{3} = 1.086 \times 10^{21} m^3 $$ The Einstein field equations, however, predict that the ...
14
votes
4answers
7k views

Can the Earth leave orbit if the population of humans and other live forms increases?

I don't know a lot about physics, but this seemed like the correct place to ask my question. I apologize in advance if it is a ridiculous one. It's actually a two part question: If the population ...
3
votes
0answers
58 views

Faster alternative to travel to any location in the west? [closed]

Suppose one needs to travel to Somalia from Indonesia(which are approximately at a distance of $4000$ miles from each other on the line of equator). To accomplish this task, I suggest the following ...
22
votes
11answers
3k views

Backyard experiments to falsify the Flat Earth theory [duplicate]

I recently became aware that the flat Earth theory still exists in the 21st century, and has colored the views of a friend of mine. Roughly speaking, the tenets are: The Earth is a flat disk, with ...
2
votes
2answers
70 views

When sunlight bounces off the Earth, why isn't the entire spectrum reflected rather than just the infrared portion?

I've read that greenhouse gases absorb and reemit sunlight, and that the infrared portion is what bounces off Earth back to space. When sunlight bounces off the Earth, why isn't the entire spectrum ...
-1
votes
3answers
142 views

A gravity question [closed]

Does gravity have a unit like length is metres?
5
votes
2answers
4k views

What if the earth's core goes cold?

What effects would occur if the earth's core goes cold? Would the planet stay liveable after this happens?
1
vote
0answers
43 views

Charge on Earth [closed]

We know that the Earth is neutral. But what will happen if the Earth becomes negatively charged or positively charged somehow?
1
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2answers
83 views

Saturn V horizontally attached to Earth

If the Saturn V rocket were attached to the ground facing in the opposite direction of the Earth's spin, would it in anyway slow the Earth's spin on its axis? How significant of an impact would it ...
7
votes
3answers
3k views

How long was a day at the creation of Earth?

Since the earth is slowing its rotation, and as far as I know, each day is 1 second longer every about 1.5 years, how long was an earth day near the formation of earth (4.5 billion years ago)? I ...
1
vote
2answers
2k views

True or false: the Moon was touching the Earth 1.2 billion years ago

A creationist website makes this argument for the 6,000 year old earth. I'm embarrassed to say I don't know how to do the math to evaluate the claim myself. However, the time scales involved seems ...
1
vote
0answers
46 views

What is the maximum theoretical height upto which our oceans can rise? [closed]

The question is framed from a physics point of view so we will assume water is an indefinite resource. All I am interested in is if we go on adding water into our oceans then what is the maximum ...
0
votes
2answers
70 views

Can we decrease the value of $g$ (gravitational pull) without gaining height? [closed]

The value of $g$ on earth surface is $9.8\ \text{m/s}^2$ and when we gain height, then the value of $g$ decreases. Pilots experience same phenomena in air, but can we decrease the value of $g$ by ...
0
votes
1answer
86 views

Why lightning most likely occure in night?

This is a question based on my experience. I am not going to prove that lightning (succeed by thunder) never occure in day, but it seems it most likely occure in night. May the humidity of air become ...
0
votes
0answers
23 views

Earth's magnetic field

New researchs found that very high pressure on certain materials may reduce the degree of temperature required to change to superconductor. So is it possible that the high pressure in earth core ...
4
votes
1answer
1k views

Why is the geomagnetic north pole at a different location from the magnetic north pole?

According to this site Magnetic North, Geomagnetic and Magnetic Poles The Geomagnetic poles (dipole poles) are the intersections of the Earth's surface and the axis of a bar magnet hypothetically ...
1
vote
1answer
105 views

How destructive would a small black hole be on the surface of the Earth?

Say a black hole with the diameter of around 200 meters or so was formed on the Earth's surface, how much damage would it cause?
1
vote
1answer
42 views

Does Earth rotation effect planes? [duplicate]

What about the supposed aiming modifications when firing a weapon? According to my research, when firing a weapon you are supposed to aim a little to the right when firing northwards and to the left ...
0
votes
2answers
62 views

Is the Earth's molten outer core affecting its motion?

According with the seismological studies [1] the outer core, with thickness of about $2300km$, starting from depth of $2,900 km$ and ending at $5,200 km$ is a low viscosity fluid, consisted mostly of ...
2
votes
2answers
1k views

Triple-right triangle experiment: what's the minimum distance?

As I had showed in a previous answer, among the other ways to prove that the Earth is round, we have the triple-right triangle. The idea is simple: Starting from point A you move in a straight ...
2
votes
2answers
127 views

Temperature of fusion in the Sun vs. fusion in controlled experiments on Earth

I recently learned that hydrogen fusion (i.e., hydrogen to helium) experiments on Earth have been successful at temperatures in excess of 100,000,000 degrees Celsius. However, I also learned that ...
6
votes
4answers
415 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 ...
3
votes
2answers
193 views

If the earth is spinning and we are spinning with the earth, why doesn't it take longer to go opposite the rotation?

Imagine you are on a walking type platform at an airport where you are walking with the platform where it moves you faster walking with......than against. This would be the same concept as if we were ...
2
votes
2answers
1k views

How many hours will there be in a day 5,000,000,000 years from now?

It is known that the moon is moving away from Earth 2cm a year, and in doing so makes the days longer. I want to know how many hours will have one day, when our planet is near its end.
1
vote
0answers
22 views

Rotation of earth and effect on $g$ [duplicate]

How do we calculate the change in the acceleration due to gravity (consider earth as a uniform sphere) with a change in the rotation speed of earth along its axis? How do we build up a mathematical ...
25
votes
7answers
10k views

If the gravity at the center of the Earth is zero, why are heavy elements like iron there?

If gravity is zero at the center of the earth, why is there a core of heavy elements, such as iron? Alternate question for the opposite hypothesis: If gravity is greatest at the center of the earth,...
15
votes
4answers
2k views

What would happen if the Earth was in a polar orbit around the sun?

This is a question that has been bugging me for a while now, I was wondering about the effects on the Earth if it was in different orbital situations to what it is now, and one of those was what would ...
2
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2answers
3k views

Why does Earth behave like Natural Bar Magnet?

What is the reason for the Earth to behave like a bar magnet and have poles (North and South poles)?
6
votes
1answer
3k views

How to determine satellite position in J2000 from latitude, longitude and distance from Earth?

Due to my task of writing orbit prediction routines I am trying to understand the reference frames better and how to use them ( particularly for Earth orbits ). I think I get the idea of what ECI (...
14
votes
2answers
2k views

Why is there a temperature gradient on Earth?

I was thinking about why the poles are colder and I came out with three possible explanations. 1. The atmosphere blocks light beams coming to poles The Sun is seen only slightly over the horizon ...
-1
votes
4answers
132 views
1
vote
1answer
59 views

Effect of radiation pressure on Earths orbit in large timescales

I have seen some posts concerning the radiation pressure exerted by the Sun on Earths surface (Force on Earth due to Sun's radiation pressure). Though it is fairly small may it have a considerable ...
1
vote
1answer
50 views

Earth as a conductor

In a lightning rod or other safety devices, charge is directed towards the earth. How the surface of the earth can be used as a conducting path despite being composed of material that is not a good ...
6
votes
1answer
1k views

If the Moon had gravity as good as the Earth and a magnetic field could it have supported life?

If the Moon had gravity as good as Earth and a magnetic field could it have supported life? Because if the Moon had gravity, it could have retained water more than is present today on the surface. ...
0
votes
1answer
61 views

Is there any way to create a globe with gravitational or similar attractive force - earth simulator?

This may sound like a dumb question. Is there anyway to create a miniature version of earth or its gravitational force. A globe or sphere which have force inside it which can attract the things ...
4
votes
2answers
622 views

Deviation from Earth's orbit

How much orbital deviation is required for the Earth to get knocked out from current orbit so it either moves away from Sun or towards the Sun?
1
vote
1answer
50 views

What happens if an object stops orbiting the sun? [closed]

What would happen if an object (like a space ship) was to stop its orbit around the sun. would time slow down with that object (the same way time sped up for the characters in that great film ...
2
votes
2answers
44 views

Space station illuminated by the Earth

Let's say that we have a space station orbiting the Earth around the equator at a speed of 360 degrees per 24 hours, always being roughly on the line between the centers of the Earth and the sun. From ...
2
votes
2answers
133 views

Why is the acceleration due to gravity $g$ quoted as if it were constant?

In elementary physics courses the value $g=9.8\:\mathrm{m/s^2}$ is used almost universally. But surely this value must depend to some extent upon one's location on the Earth. Why do we assume a ...
1
vote
0answers
68 views

Why are the cores of planets melted?

We all know that the core of Earth is in liquid form, as are most other planets as recently read. Why is this the case? Obviously, high temperatures are the cause, but what causes the high ...
0
votes
0answers
41 views

How does magnetic field gets generated by friction between high temperature molten metallic cores?

I was watching "Strip the cosmos" show on Discovery science channel last day and they explained that earth produces magnetic field due to rubbing of the two concentric cores, both the molten metal ...
-1
votes
1answer
66 views

If Earth was split into thousands of astroid-size chucks, would any of them have gravity? [closed]

I know that mass increases gravity and that less mass decreases gravity. But is there a minimum gravity amount that won't let meteors or astroids have gravity because of their littler masses?
0
votes
5answers
88 views

Static model of the Earth motion

Believe it or not, an old man I know in 2015 still negates the Earth orbital motion around the Sun. He believes the earth is rotating on itself and acknowledges this gives day and night on every ...
0
votes
2answers
71 views

How do gravity anomalies on Earth comply with conservation of energy?

Gravitational acceleration varies from place to place on Earth in a range of about 0.02 percent and is caused by density distributions within the Earth. Imagine an experiment where you move around the ...
2
votes
3answers
108 views

(How) can we determine mid-point on Earth's orbit?

The eccentricity of earth's orbit varies with time, but at present time its eccentricity is roughly mean e (0.0167). The position of equinoxes is far more complicated than I thought and it is not at ...
2
votes
2answers
145 views

Why Earth is considered to be an inertial frame? [duplicate]

Earth rotates about its axis and also revolves around the Sun at the same time. So why Earth is considered as an inertial frame in Newtonian Physics. So technically, I'm effectively asking why the ...
16
votes
3answers
2k views

Are there any exact data about Earth's orbit?

Wikipedia says that the Earth's orbit's axis is $a=149\ 598\ 000\ \mathrm{km}$ and its eccentricity is $e=0.016\ 7086$, but if we use these values to find distance at aphelion and perihelion we get $...
0
votes
0answers
147 views

What altitude you need to see the earth's curvature? [duplicate]

i have seen several videos and articles that nobody has seen earth's curvature except nasa. if someone has tried to go up to see earth curvature it seemed flat to them which makes some people to think ...
3
votes
0answers
40 views

Different time between equinoxes

I calculated from here that there are 16 104 096 seconds between the vernal and autumnal equinox, if I made no mistake, this is some 650 592 s longer than the other half orbit. I imagine this is due ...
31
votes
5answers
9k views

If the Earth is a good conductor of electricity, why don't people get electrocuted every time they touch the Earth?

Since the Earth is a good conductor of electricity, is it safe to assume that any charge that flows down to the Earth must be redistributed into the Earth in and along all directions? Does this also ...