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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Why was Galilei “right”? [duplicate]

Considering that all frames are equivalent, isn't it up to the observer to say "The earth turns around the sun" or "The sun turns around the earth"? Isn't this more or less like arguing about which ...
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1answer
466 views

Gravity anomaly in Lacnov, Slovakia: Gravity ashamed

http://www.youtube.com/watch?v=4qxwqNqL-Nc http://tvnoviny.sk/sekcia/spravy/technologie/v-lacnove-sa-predmety-kotulaju-do-kopca.html (Sorry: above links in Slovak.) Can someone explain this to me? ...
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2answers
384 views

Proofs that Earth is not flat? [duplicate]

Well, I do not believe that Earth is flat, but I met some conspirationistas believing that all physics we learn in school is twisted, all the Earth's pictures from space are photoshopped by NASA, etc, ...
5
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1answer
529 views

Measuring temperature at a distance

http://www.youtube.com/watch?v=gKYrXHZwtPw In this video it is explained that Land Skin Temperature (LST) are measured by NASA's Aqua and Terra satellites. It seems it works by collecting the ...
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2answers
837 views

Result of increasing the radius of earth?

How can increasing the radius of earth may cause an impact on the solar system ? Like, would earth may start making a bigger orbit (due to increase in size and wait) or vice versa ? or else ? PS: The ...
4
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1answer
316 views

What do you call the period after sunrise when the sky is bright?

At sunrise, the sky isn't actually up in the sky yet. Twilight occurs before sunrise, then at sunrise the leading part of the sun crosses the horizon. But, the sky isn't bright yet. It takes some time ...
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3answers
540 views

Do volcano blast changes earth's course?

Volcano blasts are one of the most powerful calamities on earth. When they blast they release large amount of mass in the air just like a jet does. Does such a blast have any effect on the course of ...
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2answers
1k views

How does one measure Earth's speed of revolution around the sun?

I know that there are several formulae that one can plug numbers into to arrive an estimate of Earth's speed around the sun (Kepler's third law for instance), but I'm wondering how these things are ...
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2answers
417 views

Is it better to build a space elevator from GEO down to the surface of the Earth?

Having just finished Arthur C. Clarke's "The Fountains of Paradise", Clarke seems to make a distinction between starting construction of a space elevator from geosynchronous orbit and working on our ...
3
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3answers
379 views

Would a sea level rise (on the other side of the Earth) if you would dip your finger into the ocean?

(I'm not a physicist & I hope this question isn't too basic/lame) The question says it all & assuming: No atmosphere No Earth rotation Not a single object in the ocean(s) Ignore all other ...
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4answers
33k views

Earth's Magnetic Field, Human Brain and Sleep [closed]

I remember reading somewhere: when you sleep in a way subjecting your body to cut the geomagnetic field at right angles, you become highly emotional whereas when it is Parallel, it cools your ...
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4answers
132 views

Revolution of Earth [duplicate]

If all motion is relative, how do we know that the Earth revolves around the sun? Or we are just making the above statement from the frame of reference in which Sun is at the origin?
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3answers
1k views

Do mankind and manmade activities/constructions have any effect on the rotation of the Earth?

We walk or ride on our vehicles to our destinations daily. Does our movement have any effect on the rotation of the earth according to Newton's law? What will be the effect if we move all the peoples ...
2
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3answers
192 views

Could we use the coriolis effect to travel

Given a platform that is floating independent of Earth's gravity, would it be possible to put a platform over the equator and over the day, would the Earth rotate from under it allowing you to travel ...
9
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5answers
603 views

sun-moon-earth anomaly

When one looks at the sun and the moon in the sky together, why is it that the illuminated crescent of the moon does NOT "point" at the sun? (More correctly the perpendicular bisector of the straight ...
2
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0answers
52 views

Is it possible to generate usable electricity from the motion or magnetic field of the Earth? [duplicate]

Let me start by saying that my knowledge of physics is almost nil (only high school level and I pretty much forgot everything) so bear with me, if I am asking naive questions the answers of which may ...
14
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1answer
453 views

What is the evidence for the super-rotation of Earth's inner core?

What are the geophysical observations that support (or contradict) the hypothesis that the Earth's inner core rotates at a faster rate than the Earth's mantle? Summary of Answers: 1) Studies of ...
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2answers
504 views

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

Among the other ways, one way to prove the Earth is round is the triple-right triangle. The idea is simple: Starting from point A you move in a straight line for a certain distance. At point B, ...
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6answers
11k views

How fast is Earth moving through the universe?

As the galaxy is moving and the solar system orbiting the galaxy and the Earth orbiting the sun. So how fast is each object moving and what is the fastest we move at? Do we even know how fast the ...
3
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1answer
492 views

Calculating the length of day at any time of the year? [duplicate]

Is it possible to calculate the length of the day at various location (distances) from the sun? I hear agricultural scientists are able to do that. To make calculations easier assume there is no axis ...
3
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2answers
109 views

Does spin of the earth vary at different locations?

Does the spin of the earth around its axis vary at different distance from the sun?,if so how does it correspond to the length of day and night,?
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8answers
19k views

Proof that the Earth rotates?

What is the proof, without leaving the Earth, and involving only basic physics, that the earth rotates around its axis? By basic physics I mean the physics that the early physicists must've used to ...
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0answers
2k views

Does gravity change the closer you are to the Earth's core? [duplicate]

Very simple question that has bugged me for some time, does the acceleration produced by gravitation (e.g. $9.8\: \mathrm{m/s^2}$) would change if we placed an observer closer to the planet's core? I ...
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2answers
2k views

Argument for proving Earth-Centered Earth-Fixed (ECEF) reference frame is non-inertial

Today I heard an argument to prove that the Earth-Centered Earth-Fixed (ECEF) reference frame is non-inertial. It seriously doesn't make any sense to me but I also heard that same argument was made by ...
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2answers
946 views

Huge buildings affect Earth's rotation?

Does constructing huge buildings affect the rotation of the Earth, similar to skater whose angular rotation increases when her arms are closed comparatively than open?
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1answer
1k views

How much negative charge do I accumulate by touching the earth?

The Earth carries a negative electric charge of roughly 500 thousand Coulombs (according to different sources I've seen). If I touch the Earth I should therefore pick up some of this electric charge ...
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2answers
152 views

Orbits within a $-\vec{r}$ field

Let's say that we have a cold dark matter theory, so we imagine weakly interacting particles. Now, let's say that one of those dark-matter particles has a rare interaction while traveling through the ...
2
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1answer
109 views

What is the Earth's magnetic field in space?

I have looked around a bit, but haven't found a simple answer. At an altitude between 100-1000 km, Is the magnetic field B still around $\sim 10^{-5}\ T$? Is there a simple equation that would provide ...
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3answers
263 views

How to create frame of reference?

Is this possible to create a inertial frame of reference in the earth? How it is possible?
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2answers
5k views

What is geostationary orbit radius?

I'm asking this apparently "general reference" question for the simple reason: I was unable to find whether the quoted everywhere "35,786 kilometers (22,236 mi) above the Earth's equator" means ...
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2answers
1k views

Cancel out Earth's Magnetic field

Is there any tools except helmholtz coil to cancel out earth's magnetic field to calibrate magnetometers in practice.
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2answers
408 views

Attenuation mass-thickness for sunset light

We are able to look directly at the sun near sunset and sunrise, which clearly demonstrates the fact that our atmosphere attenuates visible light. Let's imagine it follows the typical attenuation ...
2
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1answer
114 views

How small the earth should be for it to become a black hole

How small would the earth have to be squashed so that it would become a black hole?
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3answers
888 views

What would happen to the Moon if Earth is turned into a black hole?

Assume that all of sudden the Earth is turned into a black hole. And the moon revolves around the Earth (before turning into a black hole). What would happen to the Moon after earth changes to black ...
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1answer
164 views

Based on what does Hawking give 1000 years of time for humans to escape the planet earth? [closed]

I read it news that: Hawking Gives Humans 1,000 Years to Escape Earth How did he arrive at this figure? Whats gonna make human race extinct in 1,000 years?
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2answers
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1answer
141 views

Energy flows in the core also responsible for another of the planet’s unique [closed]

Energy flows in the core also responsible for another of the planet’s unique features: a strong magnetic field. Scientists believe that the earth has had a magnetic field for at least 3.5 billion ...
3
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1answer
190 views

Under what practical conditions would Earth's atmosphere be a dilatant?

I have read and heard in many places that when the astronauts of Apollo were coming back to Earth, they had to determine the best angle of attack to re-enter the atmosphere. This is usually indicated ...
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8answers
11k views

Would it matter if the Earth rotated clockwise?

In the Futurama episode "That Darn Katz!" they save the world by rotating the Earth backwards saying it shouldn't matter (which direction Earth rotates). If Earth rotated clockwise and remained in ...
4
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1answer
141 views

Link between Earth and Mars

I am trying to the calculate the link budget for link between a ground station on Earth (with a particular latitude and longitude) and a rover at a particular location on the surface of Mars, either ...
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4answers
412 views

Why a day is divided by 12/24 hours? Why the number 12?

Why a day is divided by 12/24 hours? Why the number 12? Why not using 10 or 6 or 14, 16? Who invented this? Any physical reasons behind this?
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3answers
1k views

Speed of the Moon

Why the motion of the Moon looks very slow in the sky? Doesn't it need the high speed in order to escape the earth's gravity?
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2answers
149 views

Spot of my light on the moon

This is a funny question, but worth answering. The distance between the moon and the Earth is 384,400 km. The speed of light is 299792.458 km/s. It will take 1.3 seconds (Approx.) for my laser beam to ...
5
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1answer
5k views

How much energy would it take to blow up the earth?

There is a common statement running around that we as a species has enough nuclear weapons to blow up the earth several times over. What I want to know is: by how many orders of magnitude is that a ...
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0answers
35 views

What is the formula for calculating the length of any given day (sunrise to sunset)? [duplicate]

In a specific date what law gives us perfect measurements and how will we measure if latitude is given?
0
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1answer
116 views

How much energy is needed to curve the space so the Sun will come 1 meter closer to our planet? [closed]

How much energy/work will it take if our planet is: 5.9736×1024 kg or 3.0×10−6 Suns to move Sun and Earth 1 meter closer ...
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1answer
59 views

What role has our Moon played in creating a persistent geomagnetic field?

The question comes from a comment by Mark Rovetta on my earlier question about the Earth's core going cold.
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8answers
63k views

Why doesn't the Moon fall upon Earth?

Why doesn't the Moon, or for that matter anything rotating another larger body, ever fall into the larger body?
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1answer
24k views

What is the extent of Earth's gravitational pull? [closed]

Where the gravitational pull of Earth exist up to? What distance from Earth it will be zero? How do the skydivers fly at a same altitude? Won't they feel gravitational pull? What is the Earth's ...
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1answer
44 views

What is the Willmore energy of the Earth (or the geoid)?

Wikipedia defines the Willmore energy as: $$e[{\mathcal{M}}]=\frac{1}{2} \int_{\mathcal{M}} H^2\, \mathrm{d}A,$$ where $H$ stands for the mean curvature of the manifold $\mathcal{M}$. What is the ...