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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Is the Earth round?

Imagine you are a common man and want to prove that the Earth is Round, how would you prove it without any mathematical derivation or without the theory of the ships.
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Does the moon affect the Earth's climate?

So, this morning I was talking to a friend about astronomical observations, and he told me that lately there has only been good weather when there was a full moon in the sky, which was a shame. I ...
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2answers
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Can a GPS system detect the decline in the rotational velocity of the Earth?

From Wikipedia: Rotation in Angular Velocity of Earth Earth's rotation is slowing slightly with time; thus, a day was shorter in the past. This is due to the tidal effects the Moon has on Earth's ...
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1answer
223 views

What will be effects of harnessing lightning?

In Feynman's Lectures, volume 2, chapter 9, there is a mention of earth getting charged by thunderstorm lightning. It is the thunderstorms throughout the world that are charging the earth with an ...
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2answers
101 views

Reaction due to gravity

There is a reaction to the gravity of the earth on us but the earth does not move due to its huge mass. But what if I combine the weight of all humans and other things on Earth? Is it not enough to ...
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2answers
307 views

7 Billion people jumping at once

What would happen if every person in the world gathered at a minimum possible area and jumped all at once? Would that have any effect on Earth?
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Do I weigh less during high tide? [duplicate]

Given weight = mass * gravity do I weight less during high tide and more when tide recedes? My guess is weight = mass * gravity * gravitational pull of moon factor
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1answer
337 views

What happens when a compass is taken to the site of magnetic pole of earth?

We know that the direction of compass needle always points towards the magnetic north pole. If we take the compass to the site of magnetic north pole, which direction will the compass needle point?
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1answer
322 views

Why doesn't the moon crash into the Earth?

I was searching about 'why do not moon crash to earth due to its gravity?'Then by reading physics stake exchange existing questions I came to know that its the sideways motion of the moon that keeps ...
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1answer
121 views

Why is the tilt of Earth in sync with an orbit around the Sun?

Is there any physical reason the changing tilt of Earth (which gives rise to our seasons: Spring, Summer, Autumn and Winter) is in sync with an orbit of the Sun (i.e. one year)? It can't just be ...
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1answer
121 views

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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1answer
167 views

Does Earth get gravity due to it's spinning? [duplicate]

Consider my example below. Example: 1. A man standing on grass(point) on earth surface. 2. He jumped. 3. And returned back, and he could find the same grass(point) under his foots. Right? If earth is ...
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2answers
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Can gravity be reversed?

I'm wondering if any set of hypothetical conditions could result in us gravitating in a different direction. Specifically a reversal of gravity on the surface of Earth (or at least part of it), so ...
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Is there a resonance within the earth, separate from the Schuman resonance?

In a very recent biography of Nikola Tesla by Bernard Carlson, the author explains that Tesla measured the resonant frequency of the earth using his invention - the amplifying transmitter. Tesla came ...
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5answers
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Earth still exists - does this fact tell us anything about LHC safety?

When LHC was about to be launched there were many fears that it would destroy the world. To counter them scientists tried to carefully examine all possibilities and concluded that there is nothing ...
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7answers
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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 ...
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5answers
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Does the Moon's core still contain significant heat?

On earth, using earth-sheltering techniques can significantly reduce the temperature fluctuations on a structure. Would the same statement be true as well on the Moon? Does the Moon's core still ...
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1answer
107 views

What is causing the Trumpet Sounds that are emited from the sky?

In these last years, a phenomenon have appeared in several countries (US, Canada, Australia, Russia, Germany, and others). It consists of sounds like a trumpet coming from our own planet's sky. ...
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3answers
102 views

What is the definition of potential energy? [duplicate]

I have problems with this equation: $$U_G ~=~ G\frac{m_1m_2}{r}.$$ It's for potential energy of say something placed on Earth. But it intrigues me. $r$ is the distance from the very center of the ...
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Why does earth spin counter-clockwise?

If we observe the earth from the north pole, we can see that the earth is rotating counter clock wise direction. The earth spins due to angular momentum, but why only in counter clock wise. Why ...
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5answers
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Build a ring around Earth, then remove the supports

What would happen if we decided to build a giant ring that managed to wrap around the whole world, end to end that was supported with pillars all along the ring and then the supports all suddenly ...
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1answer
98 views

How does Foucault's pendulum work in a place other than the poles?

I find it easy to understand how Foucault's pendulum works at the poles, the pendulum oscillates in a fixed plane and we, along with the earth, rotate around it. So it appears that the pendulum's ...
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12answers
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What is the simplest way to prove the Earth is round?

Assume you've come in contact with a tribe of people cut off from the rest of the world, or you've gone back in time several thousand years, or (more likely) you've got a numbskull cousin. How would ...
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6answers
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Why it is colder in mountains, at high altitudes?

The conventional answer is to say that "lower temperature follows from lower pressure because temperature is average molecular energy (average speed)". For instance "Temperature is a measure of ...
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0answers
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Do all stars Turn into Black Holes? [duplicate]

If all stars turn into black Holes one day, in far future, what will happen to Earth if Sun becomes a Black Hole.
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4answers
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Will the sea form a concave surface?

Without neglecting the fact that the earth is rotating, let us be in a ship (such that there is no relative motion between sea and ship) in a sea that surrounds the northern most or southern most ...
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0answers
48 views

What will be the affect of Global Warming if Polar Ice melts? [duplicate]

Due to global warming, all the polar ice melts & sea level increases, with increase in humidity. Angular momentum of ice at pole is, very low. Due to shift of water, from pole to equator, it's ...
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3answers
73 views

How far do we need to go from earth to view it as a complete sphere?

How far do we need to go from earth so that our view makes us believe that the earth is just a sphere without any terrains and depressions? It must look like a completely uniform spherical land mass.
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1answer
57 views

Centrifugal force on objects rotating around Earth

Suppose two objects travel around the equator on Earth at the same speed, $v$, in opposite directions, where the speed $v$ is measured relative to the Earth's surface. Will they experience different ...
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2answers
118 views

If 1% of total water in earth evaporates to the atmosphere due to Global Warming, what will happen? [closed]

My views Atmospheric volume increases. Mesosphere's temperature will increase. Resulting no rainfall. Some H2O molecules will escape to the space. Rotation of Earth will slow down, resulting the ...
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1answer
111 views

Forces that fall under gravitational forces

I was explaining the air motion in the atmosphere, so I introduced Gravity, Pressure Gradient and Coriolis Forces. Then one of the Professors asked me this question, which I couldn't answer. He said ...
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0answers
17 views

Density and pressure of the earth core [duplicate]

According to some sources the density of the earth core is about 9.5kg / m^3 and the pressure: 4*10^11 Pa I know the gravitational force decreases, if you get closer the center of the earth, ...
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1answer
126 views

Drift of Earth's orbit?

How much has Earth drifted (inwards or outwards) from its orbit about the sun? Or has Earth has not moved at all, compared to, say, 1000 years ago? 10,000 years ago?
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2answers
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Is the Earth the center of the Solar System? [duplicate]

Alright guys, so I attracted you with the title. Now, to preface the question, I am fully aware of the work of Copernicus, as well as the concepts of Heliocentrism and Barycentric Coordinates. I have ...
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1answer
83 views

Motion of a ball in a tunnel along Earth's diameter [duplicate]

Suppose, a tunnel is made along the diameter of Earth and we drop a ball inside it. How will the ball behave? Please help me in the stand.
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3answers
458 views

How often does the earth rotate around the common center of mass with the moon?

I could not find anywhere how long does it take for the earth to rotate around the center of mass of the earth moon system, which is located inside the earth but off-center. And does this motion have ...
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1answer
141 views

if the Earth's rotation was slowed down, would it naturally speed back up as it was before? [closed]

Fact: The Earth is rotating on it's own axis every 24 hours. Question: If, for some reason I won't specify the current speed of the Earth and could slow it down(say by 5%). Will it speed up again ...
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1answer
212 views

From Paris to … London [closed]

(Excuse the pun in the title, couldn't resist) Paris and London are connected by a straight underground tunnel, as shown in the diagram below. A train travels between the two cities powered only by ...
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1answer
121 views

Is sunlight like a spotlight? [closed]

It is believed that if earth would have no atmosphere then the sunlight would fall on earth like a spot light. According to this fact the sunlight on moon must fall like a spot light. Does it? Then ...
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3answers
9k views

Does Earth's Rotation Affect Its Shape?

The question I am working on is, "Consider the following. (a) Find the angular speed of Earth's rotation about its axis. rad/s (b) How does this rotation affect the shape of Earth?" I am fully ...
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1answer
188 views

What forces carry hovering objects around the earth with its rotation?

My questions are: a) What significant forces “carry” flying objects around with the rotation of the earth, b) How do each of those forces contribute to that “carrying”, and c) How relatively ...
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1answer
63 views

Does earths gravitational force decreases?

I feel that attractive gravitational forces on Earth is somewhat similar to attractive magnetic forces. However, because the magnet loses some of its attractive force over time, will gravitational ...
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1answer
73 views

How bright would the Earth be at night without the moon?

How bright would the Earth be at night without the moon? Specifically, how much light would reach the surface of the Earth at sea level?
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2answers
63 views

It's All About Earthquake! [closed]

All the following informations i've got are from a book.(i want to check that whether the informations are correct or not,that book isnt a science book though) There is a limit to which earth can ...
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1answer
87 views

How is it we have helium on earth?

Earth gravity isn't strong enougth to hold helium so we are loosing it constantly. If earth assembled out of space dust how come we have helium? Where did it come from?
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6answers
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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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3answers
3k views

Is there evidence to support that the Earth has a molten core?

I am told the Earth has an molten core. Is this a theory or has this been proven?
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3answers
155 views

Milky Way galaxy central black hole and time contraction of life story

We know that life is almost 4 billion years old on Earth. We also know that time contracts as we approach the event horizon of the massive black hole at the center of the Milky Way galaxy. Now the ...
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1answer
218 views

What does this sentence mean?

"The acceleration of free fall on the surface of the Earth is 6 times its value on the surface of the Moon." I interpreted it as: "The acceleration of free fall due to the Earth's ...
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1answer
63 views

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?