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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2answers
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Can a Storm make the day longer/shorter?

I've read that changes in jet streams can affect the speed that the Earth rotates on its axis, thus making the day longer or shorter?
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2answers
78 views

Properties of an object whose collision with Earth would completely disintegrate Earth

This picture got me thinking, whether such collision would be possible, and would it really look like that from the moon. What would be the properties (mass, size, velocity etc.) of an object, whose ...
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2answers
77 views

Why does the Earth rotate on its axis?

I know that the earth moves around the sun because of the gravity force, because the spacetime around the sun is curved. But why does the earth rotate on its axis, and which parameters can affect ...
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3answers
622 views

While finding escape velocity, does human mass counts as the mass of Earth?

Escape velocity depends upon the mass of earth. my doubt is whether human mass adds into it or not? If it add then Earth's escape velocity would be increasing!
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0answers
22 views

how to find whether molecules will absorb radiation of a particular wavelength or not?

I am trying to understand vertical temperature profile of Earth's atmosphere. We know that different frequencies get absorbed by molecules at certain heights. I want to show this mathematically. For ...
3
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3answers
82 views

Why is Earth's gravity stronger at the poles?

Lots of places state that the Earth's gravity is stronger at the poles than the equator for two reasons: The centrifugal force cancels out the gravity minimally, more so at the equator than at the ...
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2answers
1k views

How does Earth carry Moon with it, if it can not force Moon to touch it by gravitational force?

Earth's gravitational force is acting on its Moon in such a way that it forces the Moon to rotate round its orbit by centripetal force and carries it while rotating round the Sun by gravitational ...
7
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2answers
552 views

Why heavy elements don't sink to the core?

If earth assembled out of space dust, how come we find heavy elements like gold, silver, uranium and bunch of others that are heavier than iron on the surface? I mean silicon (Si mass 28.084) being ...
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6answers
428 views

Are metals more heavy due to the Earth's magnetic field?

Non-metal objects are attracted to the Earth due to gravity. So the weight of non-metal objects can be only dependent on their mass. On the other hand metals can be attracted to the Earth's magnetic ...
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1answer
21 views

Correcting for oblateness of the Earth [duplicate]

I'm trying to model numerically the effects of the Earth's oblateness on satellite orbits. I'm seeing precession of the orbit, but not in the plane that I'm expecting. Here's my corrected grav. ...
6
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2answers
405 views

How would gravity change on a planet rotating around itself very fast?

Let's take a planet identical to Earth, but with rotation speed multiplied by ten thousand. What would happen with the gravity if it was spinning madly around itself? Would the centrifugal force make ...
5
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1answer
141 views

How much power would be needed to make a substitute for natural Earth magnetic field?

Imagine the Earth's magnetic field will take a "maintainance pause" for 1000 years and there is gigant 10 years "doomsday countdown timer" ticking in the sky. The magnetic field will be just normal ...
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1answer
133 views

Temperature on the surface of the sun calculated with the Stefan-Boltzmann-rule

In a German Wikipedia page, the following calculation for the temperature on the surface of the Sun is made: $\sigma=5.67*10^{-8}\frac{W}{m^2K^4}$ (Stefan-Boltzmann-constant) $S = 1367\frac{W}{m^2}$ ...
4
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3answers
90 views

Why does the sea horizon line always seems to be at the same height as one's eyes?

I wonder why, when I look at a sea/ocean, the horizon line always seems to be at the same height as my eyes, no matter how many meters I am above the sea level. This is something I noticed when I ...
0
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6answers
312 views

The earth is spinning, so why don't we jump and land on a different location?

I know there are similar questions in stackexchange but i think it's different and detailed. The earth is spinning 465 meters/second so why don't we jump and land on a different location ? I have ...
34
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4answers
4k views

Why is Earth's climate so stable?

Earth wasn't always the only water-world in the solar system. Mars also appear to have started out wet but, as conditions changed, Mars lost its oceans. So, how has Earth managed to avoid a ...
3
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6answers
5k views

Where on Earth can you find plasma?

Ok, so not that 'where on earth', like literally - 'Where on Earth'. Where on Earth, can you find matter in the 4th state, i.e. the plasma state?
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2answers
46 views

Gravitational field strength inside the Earth [duplicate]

please could someone give me a relatively straight forward answer why the gravitational field strength follows a straight line (linear) relationship with distance from the center of the Earth but when ...
-1
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2answers
60 views

Is Water the only Liquid of Life? [closed]

What makes scientists think that water is better at sustaining life than every other substance? every organism we know of needs water to survive. In fact, without water, life on Earth would have ...
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0answers
25 views

If earth generates magnetic field does it attract metal? [duplicate]

If earth generates magnetic field does it attract metal objects at the surface of the planet and make them heavier?
0
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1answer
47 views

What is the longitudinal difference between the sub­solar point and the magnetic poles at time $t$ (hours)?

I'm trying to convert geomagnetic coordinate to geographic, but there are some steps in the paper which I'm reading, that I don't understand. I have the geomagnetic latitude centered around the ...
3
votes
1answer
130 views

Why is the Earth's moon so big?

It could just be me, but it seems like our Moon is WAY bigger than it should be for a planet of our size. If you look at satellite-to-planet mass ratios for the largest moons of Jupiter, Saturn, ...
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2answers
46 views

Does angular speed of the earth around the sun remain constant?

I presume that angular speed is nothing but angular velocity without direction. So, since the earth always takes nearly 365 days to complete one revolution around the sun, can't we conclude that it's ...
0
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0answers
19 views

Reason behind the rotation of Earth? [duplicate]

I want to know what is the reason that the Earth rotates on its own axis? What are the forces responsible for the Earth's rotation?
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0answers
18 views

Is the density of air in the mountains higher at the equator?

I have heard that at e.g. 5000 m altitude, the subjective feeling is better in the Himalayas than e.g. Tien Shan, because Himalayas are located near the equator, and due to Earth's rotation "air is ...
0
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1answer
82 views

How much energy is necessary to set a year to exactly 360 days

How much energy would be necessary to slow down Earth rotation such that a year was 360 days long? In the same spirit: how much energy would be necessary to make the Earth rotate faster around the ...
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5answers
1k views
0
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0answers
28 views

What if there was a hole between earth poles [duplicate]

Imagine if there was a hole between two earth poles, let's say 100 meters wide, as deep as the Earth's height between north and south poles - what would happen if we threw an object from the North ...
0
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4answers
1k views

What cosmic event would cause Sun rising from the west?

I'm wondering what kind of astronomical or geological events would cause the reversal of Earth's rotation. For instance, Is a meteorite passing very close to Earth able to reverse its rotation? Can ...
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2answers
109 views

Two expressions for potential energy in the gravitational field of the earth

Let $M$ be the mass of the earth, considered as a point mass, then the potential energy of a point with distance $r$ away from the center (assume $r > \textrm{radius of earth})$ is $$ U(r) = ...
3
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3answers
286 views

How would normal matter behave under conditions found in the core of the sun?

Considering how low the power density is at the sun's core, I seem not to be able to expect what would happen to matter in case it was thrown inside the sun's core. For example, let's assume an ...
0
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1answer
59 views

If you dig a deep tunnel, will the rock sublimate?

If a tunnel is dug deep inside the crust (but before reaching places where the rock is liquid), how will the enormous downwards pressure manifest itself? Will the difference in pressure ...
1
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1answer
49 views

Gravitational acceleration at half Earth's radius [duplicate]

What would be the gravitational acceleration at half at Earth's radius? Something tells me it should be proportional to the mass distributed in that part, but I am not sure. Of course, we assume we ...
5
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3answers
2k views

If there was a black hole on earth, what would it look like?

If an answer does exist, I'd love to hear it. I'm trying to incorporate a doomed earth story in something I'm writing, and the end of the world I'm going for is a black hole. Let's say the black hole ...
0
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2answers
33 views

How to measure rainfall? And how is it determined for a specific location?

How is rainfall measure in a pinpoint location? This is what I think: There are automatic rainfall measuring stations at: A, B, C. But say I want to know point D, located between A and B, its ...
3
votes
1answer
105 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 ...
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2answers
184 views

Earth's Temperature

I have a question regarding earth's temperature... How come the average temperature in the middle east (Israel, Saudi Arabia, Sudan or lower) is always so much significantly higher than in Europe ...
11
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2answers
346 views

How are the northern lights produced?

Although I've never seen it myself, I hear the northern lights are a sight to be seen! I know they're related to the Earth's magnetic field but I don't know much more about them. What is the physical ...
0
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0answers
30 views

Cause and properties of northern lights [duplicate]

If outside on a dark night in the middle to high latitudes, one might be able to see an aurora. It may be several hundred kilometers high and several thousand kilometers long, stretching around Earth ...
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2answers
149 views

What if an asteroid the size of the moon hitting earth

Would we all parish due to excessive heat? Or would that be only limited to the area near the impact while as the people on rest of the earth would die from other phenomenons such as mega earthquakes, ...
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4answers
1k 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 ...
0
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1answer
55 views

How powerful would an explosion have to be for its effects to be felt worldwide?

If an explosion were to occur at any point on earth, how powerful would that explosion have to be for it to be audible or otherwise detectable by every person on the planet? Detection could mean ...
1
vote
1answer
34 views

Why does absorption cause seismic pulses to increase in length over distance?

The specific question I'm trying to answer is "How does the progressive loss of higher frequencies in a propagating seismic pulse lead to an increase in pulse length?" I understand how the higher ...
2
votes
1answer
322 views

Why does earth cool? [duplicate]

This question is boggling me for some time. We know that heat can be transferred from matter to matter and heat is nothing more than tiny atoms vibration intensity (correct me if I'm wrong). But space ...
8
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2answers
113 views

Does the geomagnetic field rotate?

The Earth rotates about it's own axis. Do the geomagnetic field lines rotate due to this rotation or not?
35
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6answers
5k views

How can the Earth keep spinning with a liquid core?

In regards to the 'conservation of angular momentum' being the explanation of why celestial objects spin... If you fill a ball or any other container with a liquid and try to spin it, you will not ...
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2answers
56 views

Is it really okay to treat the Earth as stationary when doing free fall experiments?

Typical treatments of free-fall experiments treat the the Earth as fixed. Using this model, object being dropped moves toward Earth, but the Earth doesn't move toward the object. A more detailed ...
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2answers
54 views

Is the gradual progression of day(light) into night a clue that the earth is a sphere?

If the earth was flat, would the transition between day and night be sudden?
2
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2answers
50 views

What is the value of $g$ at centre? [duplicate]

What is the value of $g$ at the centre of the Earth? Is it zero or infinity? My attempt: I know it's zero but applying law made me on fused.
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0answers
24 views

Do we feel the full force of the earths gravity even though the earth is spinning [duplicate]

As far as I know, since the earth is spinning, centrifugal force should be throwing you off the earth. However, gravity counteracts that by being a stronger force. So if you stood an object with the ...