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 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 ...
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1answer
64 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 ...
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1answer
77 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 ...
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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 ...
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2answers
34 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 ...
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1answer
301 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
193 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 ...
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2answers
350 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 ...
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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
328 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
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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 ...
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1answer
67 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 ...
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1answer
50 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 ...
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1answer
325 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 ...
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2answers
116 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?
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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
69 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
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2answers
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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
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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 ...
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2answers
131 views

Antipodes are mostly ocean - so what happens after digging that hole through earth?

Digging a hole through earth is a common thought experiment, often used to explain effects of gravity. But what would happen if someone finally dug the hole? Sure, he took care to stabilize and ...
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2answers
370 views

Day/night cycle in Greenland

I have heard that in Greenland there is day for 6 months and night for 6 months. Is this true? If so, how does it happen?
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0answers
42 views

Terrestrial Space Elevator Construction - Plausability

Framework If there was a cable constructed at the equator about the circumference of the Earth, and if this cable had sufficient strength to remain intact while erect, call this tensile strength T. ...
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0answers
26 views

Variance of daylight over short periods of time?

I've searched various publication archives but I'm a signal processing engineer and not an applied physicist, so I might not be using the right terms. While I can find various average values for the ...
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1answer
64 views

Do objects in free-fall contribute to earth's weight as a whole still?

If everything in earth's atmosphere contributes to earth's overall weight, including air etc. Does an objects weight in free-fall effect this overall weight in anyway. Just say the weight of earth ...
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1answer
61 views

Earth's magnetic field

I'm dealing with a problem here. Today my professor asked us a question : How should a metallic wire move in Earth's magnetic field such that she gets maximum potential difference in it's ends: a) ...
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4answers
102 views

Bulk flow of air in a long tube between Antarctica and Australia?

I have a 5km diameter clear plastic tube which is open at each end and runs from the center of Antarctica to Lake Eyre in Australia. The tube is on the ground where it can be and at sea level on the ...
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5answers
1k views

Why the water remains on the surface of the Earth?

What makes the water stay on the surface? Why the earth does not absorb the water in it?
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51 views

Could there be a planet just as the Earth, but bigger?

Could there be a planet twice or thrice the size of Earth but while being the same? and by the same I mean, hosting the same life as Earth, having a day last 24 hours and a year 365 days. Basically, ...
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2answers
119 views

Does the Earth's core have tides?

Does the moon produce a measurable tidal-effect on the Earth's (liquid) core? If so, how strong is it? Would it play a factor in other geological effects like earthquakes, volcanoes, etc?
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5answers
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How much does the Earth's rotation affect a golf ball?

When launching rockets into space, they start straight but begin to lean, I assume due to the Earth's rotation. For something on a much smaller scale, such as a golf tee, is there a measurable ...
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2answers
87 views

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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7answers
835 views

How does heat actually stay kept in the carbon molecules in the atmosphere? [duplicate]

We have all learned that the earth is getting heat up because of the CO2 and CO molecules absorbing heat. However, how is heat actually kept in those molecules. When photons heat them up, their ...
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3answers
101 views

What is the constant $g_0$ used for calculating the specific impulse in seconds?

Wikipedia defines specific impulse as: $$ I_\mathrm{sp} = \frac{F_\mathrm{thrust}}{\dot{m} \cdot g_0} $$ The $g_0$ is said to be the acceleration at the Earth's surface. So is it actually the ...
5
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3answers
530 views

Gravitational force of the Earth [duplicate]

Why does gravitational force of the Earth decrease as we move towards the centre of the Earth? Where as inverse square rule says that distance is less than gravitational force is more.
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4answers
172 views

Sun revolves around the Earth [duplicate]

What if somebody says that Sun revolves around the Earth and not Earth revolving around the Sun? What would be the consequences?
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1answer
60 views

Does gravity act in the centre of the Earth? [duplicate]

If we we dig a hole from north pole to the south pole of the Earth and we throw a ball in this hole where would it stop? Will it come back on the surface or it will stop at the centre?
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3answers
66 views

Why do grey body radiators not heat up?

So I'm doing so work on the earth's climate system, and modelling it as a grey body radiators, and I've come across the phrase: "$62\%$ of the outgoing energy is lost to space and the other $32\%$ is ...
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1answer
57 views

What would happen if I was in the centre of the Earth? [duplicate]

If right in the centre of the Earth would be like a hole and I could teleport right there, what would happen to me? Would I explode, implode? My own theory is that maybe I would levitate because since ...
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0answers
65 views

Is it true that the sun will cause very high temperatures on Earth long before the red-giant-phase?

I heard at least three claims about the development of the heat of the sun. In an old book, I read, that nothing dramatically will happen in the next few billion years. Wikipedia states, that the ...
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1answer
83 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 ...
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2answers
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What will happen when “earthing” is not an option?

I know that earth has a very high capacitance (of about 711$\mu$F) and it would take a lot of time for this but since we earth almost all our appliances for safety, wouldnt one day come when earth ...
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2answers
250 views

What would happen to wet laundry in the vacuum of space?

Imagine for a second that I was in a college dorm room frustrated that all the dryers were broken or in use. I'm impatient and not a jerk so I don't wait or take out someone else's laundry, I shoot it ...
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1answer
39 views

Regarding the theory of the origin of water on earth through meteorites, why wouldn't the water evaporate on impact?

Water on earth has been theorized to have come through comets trapped inside crystals. But why wouldn't that water evaporate on impact, and wouldn't the atmosphere at that time allow the vapours to ...
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3answers
830 views

Are the air particles in today's wind on earth (more or less) the same as the air 2/3 billion years ago?

So the air pressure on earth remains relatively constant, right? Is there air gained or lost through transitions of any sort? e.g. plumes going out into space, earth gaining new air particles with ...
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3answers
503 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.
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1answer
255 views

Effect of Earth's magnetic field on aeroplanes?

As an aeroplane accelerates through the Earth's B-field, it experiences a changing flux $d\phi \over dt$ and a potential difference is induced along its wings. Given the wings are made of metal and ...
4
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5answers
295 views

Would dropping large blocks of ice into the ocean mitigate global warming?

This amusing Futurama sketch 'solves' global warming by dropping increasingly larger blocks of ice into the ocean. Presumably the blocks of ice are harvested from a different planet. Would this ...
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0answers
55 views

Why doesn"t centrifugal force throw us off the earth? [duplicate]

I was drawing a diagram and trying to resolve all the forces. It seems to me that because of gravity, centrifugal force will produce a sort of "dragging" motion along the surface of the earth. The ...
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0answers
107 views

Compute and plot satellite position on 2D Earth map

I would like to create a simple satellite tracking software, that will compute the position of a satellite at any time, and show its location on a 2D map of Earth. Let's assume it is possible to ...