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Questions tagged [earth]

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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Electrical systems with multiple connections to earth - is earth modelled as one region of equal potential here?

In the picture we can see a realization of a TT-System, an electrical system with multiple connections to earth at different localiations. I allready know (from this question) that the coulomb-...
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Conservation of Angular Momentum — Earth-Moon System — Earth spin backwards?

I am developing an exhibit for a museum. We want to show how the Earth's spin rate changes as the Moon drifts farther and farther out from the Earth. The visitor has a slider they can move to set ...
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1answer
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Why $g$ on equator is less than $g$ on poles? [duplicate]

I found this on my physics book. The book says $g$ on equator 9.78 $m/s^2$ and on the poles 9.81 $m/s^2$. Is it due to gravity?
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2answers
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How much change in Earth's orbital distance to change average temperature by 1°C?

How much closer/farther would the Earth need to be to/from the Sun to effect a $1 \sideset{^{\circ}}{}{\mathrm{C}}$ increase/decrease in average temperature?
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3answers
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Is there a difference between the red sky in the morning and in the evening?

It certainly has a different feeling to it, but does the temperature or earth's rotation or the clouds or anything else really make it two different physical phenomena or at least different colors? ...
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Motion at absolute 0 in relative to [duplicate]

Hypothetically, if we could get some type of particle to be at absolute 0 would it be technically still have relative motion due to an observer outside of earth. E.g earth is moving therefor particle ...
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Do variations of the Earth's magnetic field affect gravitational acceleration at Earth's surface, and if yes, by how much?

The Earth's magnetic field varies with time over geological time scales (we have phenomena such as pole inversion). Can this affect the acceleration of gravity at Earth's surface? I would think that ...
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Why doesn't the Earth lose its magnetic properties? [duplicate]

I learnt in junior high that magnets, when exposed to heat, usually tend to lose their magnetism. Similarly, the Earth's core is also hot, but it doesn't lead to the loss of magnetism of Earth. Am I ...
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Estimating the Pressure of Earth's Center

The pressure of a medium of density $\rho$ and in a graviational field with strength $g$ at a depth of $z+dz$ is equal to the pressure at $z$ plus the pressure caused by the weight of a slab of volume ...
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A confusion between geocentric and heliocentric model [duplicate]

As per Ptolemy, he proposed firstly geocentric model and that model if one see with aspects of relativity he would find true. Here is an example how Suppose you are in a train which is moving and you ...
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1answer
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How much does temperature affect the time of sunrise?

Please forgive me if this is a dumb question, or if my understanding of basic physics is wrong. Please feel free to correct me. As I understand it, if the Earth didn't have any atmosphere, then the ...
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How fast would an object at cruising altitude (around 10,600 m) need to travel to stay on the opposite side of the Earth to the Moon? [closed]

I am trying to figure out how fast an object will have to travel (at a height around 10,600 m) to never be in the presence of the moon. Meaning the object will always be on the opposite side of the ...
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Did Eratosthenes make his measurements on the same day?

Erasthosenes measured the circumference of the earth on the summer solstice by observing the sun at Alexandria and Syene. Was this done on the same day in one year or on the same day in two ...
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1answer
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If I drive East, how much lighter am I than if I drive West?

I'm at the equator. Suppose I am driving at x kph, in the direction of the Earth's rotation (i.e. due East), I presume that the force my vehicle exerts on the ground is less than when I am stationary. ...
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1answer
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How does the Earth's radial acceleration affect it's velocity during orbit around Sun? [closed]

When the earth moves along its ellipse at $67,000mph $ it accelerates at $0.006m/s^2$ would it be correct to say it's speed at some points relatively increases by $0.006m/s$ every second
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What's the Earth's linear acceleration component around the Sun?

The earth's centripetal acceleration around the Sun is $0.006m/s^2$ does this mean one can say the earth's acceleration when it travels(revolves) at $670,000mph$ is simply equal to its centripetal ...
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Large objects in the universe sized by gravitational and electrical constants

In a famous talk (from 14:30 to 15:00) Nima Arkani-Hamed tells us that what "fixes the size of the earth" is the equilibrium between the gravitational pressure against the atomic pressure of the atoms ...
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Does current flow when you connect a battery to earth?

Let's say that the earth has 0V and everything is ideal, does current still flow and why?
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Need an equation to calculate the list of latitudes and longitudes of an off-nadir sensor with a given half angle

I need a deterministic way to determine a list of latitude and longitudes of an off-nadir pointing sensor for a given half angle. Below is a depiction of the problem. It isn't too hard to calculate ...
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1answer
86 views

Is gravitation on earth less in nighttime than in daytime?

I have been thinking on the effect of the centrifugal/centripetal forces from the orbital movement of the earth around the sun, which might perhaps affect the gravity. In nighttime we are on the ...
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2answers
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Is the period a physical observable in General Relativity?

I am currently seeing the classical tests of GR. To justify the introduction of a test based on the Doppler effect, the professor says that the previous test ( Shapiro and echo-radar test ) is based ...
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Is one side of earth faster at night and slower at daytime?

I'm reading Physics for Entertainment by Yakov Perelman and in it he says under "When we move around the sun faster" that at midnight the speed of the rotation of the earth is added to that of earth's ...
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1answer
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Measuring the earth's electric field

My question stems from a question on the Dutch VWO-level highschool state exam (from 1993) concerning a device to measure the earth's electric field. It consists of two plates positioned above one ...
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1answer
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Is the Earth orbiting an 'illusory' Sun, owing to the 'speed' of gravity? [duplicate]

We see the Sun about eight minutes after light left it. Presumably this means we are also experiencing the Sun's gravity 8 minutes after it 'left' the Sun. So are we orbiting around the Sun we can ...
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4answers
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Is Earth an inertial reference frame?

Is earth considered as inertial frame? i was confused because we learned about coriolis effect. We know that earth spins therefore coriolis effect should take place . But does it have minimal effect ...
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Can magnets be arranged to interact with earths magnetic field to produce force?

Is it possible to arrange one or more magnets along with iron/ferric guides to interact with our planets magnetic field in such a way that a force is generated in one or more directions? Would a ...
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1answer
478 views

How do we know the Earth's core is Molten with Seismology?

My current knowledge about how the core of the earth was discovered is the observation made from non returning/reflecting sonar signal when sent to deeper depths through the earth's crust/mantle. How ...
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0answers
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If the Earth would change into a ball of water, how wil its form develop, considering only the Sun's and Moon's influence? [duplicate]

Let's fantasize that the Earth changes in a non-rotating ball of water. And let's assume the only gravitational influences on it are those of the Sun and Moon. What will happen to the form of the ...
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2answers
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What happens to the water on the surface of the Earth if the Earth is not rotating about its axis in the Earth-Moon system?

Suppose the Earth is not rotating. As usual, the Moon follows its normal path around the Earth. Let's assume it's a circular motion and that there are no other gravitational influences. A test ...
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1answer
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A question about horizontal doppler effect on galaxy hydrogen radiation observation

The figure shows the positions of the solar and neutral hydrogen regions A to D rotating in a circular orbit relative to the center of the galaxy. The sun and A to D assume a Kepler rotation. ...
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Confusion about angular momentum of earth moon system

My assumed definition of angular momentum is the sum over $i$ of $L_i =r_i\times{\omega_i}\times{r_i}$ for each particle about some origin. We have two spheres rotating about the centre of orbit. For ...
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How to calculate weight of an object orbiting another object?

How do we calculate weight of an object which is orbiting another bigger object in the space? For example, comparing the pair of Sun-Earth, Earth is orbiting Sun due to the force applied by Sun on ...
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The acceleration in Earth's gravity

The acceleration in earth's gravity is $9.807 m/s^2$ at my location. But is this value uniform in the entire earth? For example in the inner core or outer core. What is the acceleration in the center ...
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1answer
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How much does NASCAR affect the rotation of the Earth? [duplicate]

Many of us will be familiar with XKCD 162: Angular Momentum, in which someone spins counterclockwise to slow down the rotation of the earth and make the night longer. The mass of an individual human ...
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5answers
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Why does the Earth not lose its magnetism?

A magnet loses its magnetic properties when subjected to heat, the Earth's core is also hot but still it has magnetic properties, Why?
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25answers
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Simple check for the global shape of the Earth

I have been on a date recently, and everything went fine until the moment the girl has told me that the Earth is flat. After realizing she was not trolling me, and trying to provide her with a couple ...
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1answer
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The Earth's Equatorial Bulge [duplicate]

It is stated that the Earth is a 'squashed sphere' due to the very slight bulge at the equator. (Thought in reality it's such a small difference, it's essentially spherical) Typical values: ...
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2answers
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Innermost stable circular orbit in Schwarzschild solution

I've been reading about GR recently and I can follow the derivation of a Schwarzschild solution to it's final and well known form in Schwarzschild coordinates. The orbit stability argument (for a ...
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1answer
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Measured Earth local gravity

I am looking for measured data of the local gravity on Earth. I know this website (https://www.ptb.de/cartoweb3/SISproject.php). The idea is nice but it looks a bit old and I would like to have an ...
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Blocking of infrared radiation from the sun by $\rm CO_2$ [duplicate]

Why is the infrared heat from the sun not prevented from entering the earth's atmosphere by $\rm CO_2$ to the same extent that it is prevented from leaving the Earth's atmosphere?
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Direction of Coriolis force [closed]

My doubt is all about finding the direction of coriolis force by using the direction of the moving object. I really find it difficult to determine the direction of coriolis force through direction of ...
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4answers
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Is there any way looking at Stars from that I can understand that we are revolving around the Sun?(Not caring about other planets for now)

I am learning Astronomy. I videos or lessons I look at are already biased over heliocentric math to explain the parallax concept. I am looking for an intuition to get myself a deeper understanding of ...
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4answers
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What is acceleration due to gravity at the centre of the earth? [duplicate]

When I asked my teacher that what is the acceleration at the centre of earth, he replied that it is 0 as when we move inside the earth, the effective mass decreases i.e. the mass that exerts ...
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1answer
278 views

What would really happen if somebody dropped a small black hole into the Earth?

Suppose we drop a small black hole, but large enough that it accumulates mass more quickly than it radiates it, into the Earth. What happens? This question has already been asked here and here, but ...
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2answers
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Do we see an ellipse when we view Earth's horizon?

I wanted to try to determine mathematically exactly how much curvature one should see on the horizon when I viewed it from a given height, and it hit me that looking at the horizon is not the same as ...
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203 views

Why doesn't Foucault's pendulum show Earth's spin at the equator but works at the North/South poles

If you where directly above the North/South pole and set up Foucault's pendulum, why does it show the Earth's spin even though the Earth isn't spinning there? This is also where it takes the shortest ...
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How can we have different speeds relative to a same point for a same object?

A day last not the same at all altitudes (https://aapt.scitation.org/doi/10.1119/1.5000802), meaning earth has different angular velocities. What is the actual rotation speed of the earth to the ...
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Detecting Earth’s Changing Speed Will My Idea Work?

Is there a way to detect the earth’s changing speed as it orbits the sun? I’m thinking of an at home experiment. It would be a plumb bob suspended in a tube about ten feet in length. There would be a ...
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Microwave links

If the record for microwave links is 235km long, and the microwave waves must travel in a straight line (and cannot go through solids such as the sea or objects in between), then how did they account ...
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Life around a different element from Carbon [closed]

On Earth, life developed around Carbon (and Hydrogen and Oxygen). I guess this depends on the availability of those elements, but also on the spectrum of radiation and Temperature and Pressure. Under ...