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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How did the Moon survive next to the Earth since earth and Moon came into existence?

What mechanism(s) prevented the gravitational effect of the earth on the moon from shattering the moon when it was closer to the earth than the Roche Limit some 4.5 billion years ago?
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How to measure the mass of Earth?

I was wondering how you can measure the mass of Earth. From what I find on the internet, people are using Newton's Laws. But how can you do that ? Newton's Laws are assumed to work because you know a ...
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Why Earth is not a cuboid? [duplicate]

There must be some scientific reasons for why earth is a spheroid but what are they? If Earth would be a cuboid, Would it matter?
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Did God have enough water to flood the earth during Noah's time? [migrated]

In Genesis 7:11-20, we read how God destroyed the living beings on earth--save for Noah's family-- using flood. In the six hundredth year of Noah’s life, on the seventeenth day of the second ...
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Why is Earth's gravitational pull only at its center?

Why is Earth's gravitational pull only at its center? Does acceleration due to gravity remain constant wherever I go in and on the Earth?
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Variation on the “Hole through the Earth” problem

In the news recently was the announcement that the answer to the classic Newtonian mechanics question of the time it takes for a body to fall all the way through the Earth was corrected to account for ...
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Why isn't $g$ larger on the equator? [duplicate]

I understand that at the equator, you will have maximum centripetal force acting on you, whereas if you're standing directly on the pole you will have none. But because centripetal is a resultant ...
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Is it possible that Mercury collided with Earth, thus creating the Moon?

I recently heard a theory that Mercury might have been bigger before a massive collision that shrunk it and sent it on its current orbit. I also heard that a possible explanation for the formation of ...
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Will the day/night cycle change when the poles melt?

I want to know what will happen to day and night if poles melt i think it will change but I don't know why? ^_^
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How do we age if we tunneled to Earth's core?

Scenario Suppose there exists an advanced technology that can hypothetically transport living humans to study the center of the Earth, as they goes deeper underground most of the Earth's mass would ...
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Since Earth spins, would an aircraft travelling opposite to direction of Earth spin take less time? [duplicate]

Suppose we want to reach the point on earth which in relative terms is exactly on the opposite end of the sphere we call earth (I know it is not an exact sphere). We either dig vertically downwards, ...
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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 ...
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Earth's direction in space [closed]

After watching videos about the rotation of the planets being helical and not heliocentric, I wondered, as Earth travels through space, which part of Earth is the forefront?
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Does the rotation of the Earth affect time?

If the Earth were to spin from east to west instead of west to east, how would that affect time or our perception of it?
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Wouldn't dark matter throw off the calculation of Earth's 'light' mass and estimates of its composition?

The Cavendish experiment first determined the mass of the Earth and (arguably) the gravitational constant. However, given the ubiquitous nature of dark matter, it seems reasonable that at least some ...
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What happens if the Russians decide to nuke the Kola borehole?

I recently came across research on the Kola Superdeep Borehole in Russia. It's one of the world's deepest at 12 km (7.5 mi) down. If someone decided to hoist a nuclear weapon all the way down and set ...
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How would a huge ball of air look in space from outside and from inside?

If you replaced the Earth (except the atmosphere) with air and kept the pressure linear to the center (of the now non-existing Earth) while ignoring the effects this would have on gravity and leaving ...
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3answers
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If the Earth's atmopsphere spins with the earth due to friction, why is there no horizontal spiralling drag?

Imagine a bucket of paint with a spinning ball in it. The paint would form a spiral and would not all move in synchronous movement with the ball. To clairfy - In order for the Earth's atmosphere to ...
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Name for Earth?

What is the proper word for 'Earth', as in 'Solar' and 'Lunar'? I cannot find this anywhere; I am guessing there is a word that starts with geo?
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Average surface temperature of Earth [duplicate]

I had a question in my school exam. Will the average surface temperature of the Earth be lower or higher, if there was no atmosphere? Now, the answer expected is "The avg temp will be lower, because ...
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Does the strength of a beam of light determine how much distance it can travel?

If I point a light torch to a cloudless, crystal clear and an absolutely pristine sky, will the light beam exit the planet and travel forever in the vacuum of space? (assuming it doesn't get perturbed ...
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Which will collide first, the moon and Earth, or Sun and Earth?

As time progresses, which scenario will happen first? The moon colliding with Earth, or the Earth colliding with the Sun? I figure the Moon and Earth will happen first, based on proximity, but the sun ...
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How does the Earth rotate, given that the torque acting on it while revolving is zero?

I've come to understand that the torque acting on the Earth while revolving the Earth is zero. Torque is the force responsible for rotation of a body. So how does the Earth rotate?
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How does the earth do a negative work on a static body? [closed]

If a body is in rest and the earth acts with a force on it 10 N Is there a negative work done by the earth though the body doesn't move? how? does it have a common thing with potential energy?
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Does the Moon have rotation about its axis?

As I understand, the Moon is following Earth's curved space. If that's the case, shouldn't the Moon have no rotation if it's tidally locked, and only appear to have rotation? If the Earth suddenly ...
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How much time would it take for a free-falling ghost-like object to cross the entire Earth? [duplicate]

We have an object of mass $m$ which can go through matter like a ghost. It's only affected by gravity, not by any other force, so it's in free fall. At the instant $t=0$ it is at the surface of the ...
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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 ...
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Chemical composition and structure of Earth's inner layers?

How exactly do scientists determine the chemical composition and structure of Earth's inner layers, for example that the outercore is composed of liquid iron and nickel, and that the mantle is is ...
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Earth's magnetic effect on my magnet

My magnet seems to work independently of, and unaffected by, the Earth's magnetic field, yet the magnetic field of my magnet changes as I introduce some other similar magnets of varied sizes into its ...
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Can we get energy from the Earth's rotation?

Is there any way to harvest large amounts of energy from the Earth's rotation?
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How can one know for one's self how big the earth is?

I want to know how big the earth is. I have heard of double sun set experiments, but it appears that you need to know you latitude, which I do not. I want to do this without using any outside ...
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How much potential fusion energy is in Earth's ocean?

Assuming the most efficient manner for extraction, and a ready supply of other necessary materials not mentioned herein, and given the current estimates about the volume of Earth's ocean, how much ...
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How much energy would it require to send Earth to Proxima Centauri?

Assuming 100% efficiency of energy usage, and given the current estimates about the mass of known objects in our solar system, including Earth itself, and assuming no other objects are affected by ...
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If I am a light travel around Earth, what relativistic phenomenons do I have?

In school, or even in university, we are only taught Lorentz transformation in one direction. It is quite easy: $$\begin{align} t' &= \gamma \left( t - \frac{vx}{c^2} \right) \\ x' &= ...
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Infinity problem: Why is gravity $g=0$ zero at the center of Earth if according to Newton gravity formula $g=GM/R^2$? [duplicate]

It is said that value of $g=0$ at the centre of the Earth. $g$ is calculated using the formula $$ g=G*M/R^2.$$ When $R = 0$, $g$ approaches infinity. I have two ...
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Why doesn't Earth's atmosphere form bands due to different rotational speeds?

If the Earth's atmosphere is rotating at the same speed as Earth, then the atmosphere must be rotating much faster at the equator than at the poles. If you spin a ball covered in oil, it will form ...
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Where did earth's electric charge come from?

I get between .7 and 1.3 volts out of a 20 foot tree depending on the weather. I understand this is "telluric" electricity with pretty low amperage. Where is this charge coming from? The sun, right? ...
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If earth's magnetic field disappeared, would cosmic radiation lead to increased radioactivity?

This is about the effect of cosmic radiation on earth. Is it the type of radiation that could make things radioactive? So if earth's magnetic field weakened considerably (such as could happen if it ...
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Solar plants and energy conservation

I'd like to apologise if this question is stupid or if it was asked ten thousand times - I haven't found an answer to it. Quite possibly due to mediocre English or abominable knowledge of physics. ...
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If you are on Earth, are your mass and weight the same?

I was wondering how mass and weight are different so I Googled it. I found that mass is constant no matter where you are because it is the amount of matter in an object and weight changes because it's ...
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How the Moon causes the tides?

I am considering the following question but I con't quite figure it out... I have looked up differential gravity but I cannot derive the equation for the effect on earth, and I haven't found any ...
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How is north defined for any point on the surface of the earth?

While studying about terrestrial magnetism, references were made to north direction, and the geographic meridian and later magnetic meridian defined using that. But what is actually the north ...
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Could we have a black hole on Earth? [duplicate]

There was once a Far Side cartoon in which a black hole had opened in someone's living room and was sucking the furniture, people, pets, etc to the middle of the room. It was a funny picture, but ...
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Does radiating heat to outer space through the atmospheric transparency window have any impact on heat loss?

I was reading this article: Passive radiative cooling below ambient air temperature under direct sunlight The authors are improving upon the age-old idea of reflecting incoming sunlight while ...
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Is It Possible To Move The Earth In A Direction? [duplicate]

According to Newton's 3rd law, when an object moves upward, the Earth moves by a very tiny factor in the opposite of the direction of the object. And when the object falls back, the earth moves back ...
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1answer
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Why is the Earth self-rotating? [duplicate]

What drives this happen? Would it be the internal energy or by an external force? I did try to Google the answer, but could not find a good one.
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If earth stopped spinning how much heavier would 1kg feel [closed]

My girlfriend seems to think if the earth stops spinning we will all fall off However, she did spark my imagination, due to centripetal force things must feel lighter then they otherwise would on an ...
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Physics Riddle - Know Plant Earth [closed]

I hope it's OK to ask here, because it's pretty much as basic as physics can get. So here it is: I have a hot air balloon that can rise to any altitude I'd like, a precise watch, a sandbag, a weigh ...
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I was told that if the Moon had a retrograde orbit, tides would have a faster rhythm. Why is that?

Would this be because tidal deceleration causing the Earth to spin faster or are there other actions in play that I haven't considered? Would the Earth even spin faster because of the tidal ...