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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Thought experiment: Could the Earth be cooled by pumping refrigerant?

Possibility of Using a Refrigerator to Cool the Earth I understand that the Earth as a whole cannot be cooled directly by radiating energy away for theoretical reasons. Waste heat has low entropy; ...
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367 views

Does Earth's Gravitational pull increase with time?

Gravitational field depends on mass ($g = \frac{GM}{r^2}$) and every year many outside cosmic objects like asteroids or tiny object are hitting earth. So I think may be in a very microscopic amount ...
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What happens if I place myself on a land pole?

What happens if I place myself in the center of one of the Earth's poles? Could I see how the earth revolves around me?
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Is the gravitational force for an object on the surface of earth always pointed to the center?

I thought it would be so because the mass inside the earth would attract us however they would be at a larger distance than masses on the surface of the earth. For example, consider having a tall ...
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Ptolemy physic astronomy

in Claudius Ptolemy physic of universe did earth is sphere or Flat ؟ did earth orbit around itself or it is stable? why he think star have impact on human life ?
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Angular momentum of the earth

We know the tidal waves are decreasing the spin rate of the earth which causes the days to longer, so as the angular momentum of the earth decreases it means it rotational kinetic energy also ...
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2answers
67 views

Does Acceleration due to Gravity take into consideration the centrifugal acceleration due to Earth's spin?

Is the gravitational acceleration we consider only the attraction due to the Earth's gravity or is it that of gravity plus the attraction due to Earth spinning? We know that earth produces an ...
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1answer
42 views

where do the gases such as hydrogen and helium end up after leaving the earths atmosphere?

I've heard that gases like hydrogen and helium leak out of the earth's gravity a little by little. but where are they going? where do they end up after leaving earth's pull? would the sun pull them ...
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Cumulative Sun's radiation pressure exerts on Earth's surface

I have some discrepancies in what is in "Optics" (E. Hecht) and what I calculated, but it's simply formula, so I'm confused. I used: $$F = \frac{\pi R^2 S}{c}$$ to calculate cumulative force of ...
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25 views

Why does the earth and oceans emit primarily infrared photons?

Climate on earth depends a lot on infrared photons being emitted by the earth and its oceans. I want to know why the atoms in earth elements emit infrared photons after absorbing visible light, UV ...
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How high can you jump (at the corner) on Cube-Earth?

I have read this question: Is the force of gravity always directed towards the center of mass? And G. Smith's answer lists a site where they specifically talk about this case mathematically. https:/...
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What (and if) is the difference in the form of the tidal bulges on the Earth with a smooth surface and the rough surface as it actually is?

It's clear that on a smooth surface of a massive sphere $M$, covered with water, two bulges of water appear when it's rotating in sync with a satellite (a massive sphere with a substantially smaller ...
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Schumann resonance frequency

I keep hearing that Schumann resonances have been increasing rapidly in recent years. And that it was relatively stable before. I failed to find any scientific data proving or disproving this. I would ...
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Gravity force inside the Earth

It is a well known exercise on classical Newton's gravity that assuming that the Earth has an ideal round shape to compute its gravity force at the given distance from its center. (Answer: it is equal ...
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I want to know about the synodic and sidereal months. Why is there a difference between the two? [closed]

I want to know about the synodic and sidereal months. Why is there a difference between the two?
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Why doesn't Einstein's general theory of relativity seem to work on Earth?

I am new to physics and I have learned a little bit about gravity from Einstein's perspective. The gist is that heavy objects create curvature of spacetime, and free-falling objects move on the ...
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Electrons @ battery negative terminal [duplicate]

Does the negative terminal of a battery have a negative charge due to having a surplus of electrons? If so, then why do the surplus electrons from the negative terminal of the battery not discharge to ...
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Can I use current state of radiation levels to have a rough estimate on natural background radiation or do I need to average over longer timescales?

If I look at EU's radioactivity monitoring map: I get the impression that most of Europe's Gamma Dose Rate is below or around 100-200 nSv/h. If I convert this value, lets say 150 nSv/h (and looking ...
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Can Earth's Magnetic Field Be as Less as -85μT and as Much as +70.46μT?

What did create the question? I was analyzing a data set where the researchers have used objective data. They have calculated earth's magnetic field through sensors and that research was conducted in ...
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67 views

Deriving gravitational acceleration from the formula for the force of gravity [closed]

I'm trying to derive this $g = 9.8 m/s^2$ from this $$F = G\frac{m_E\cdot m_2}{(r)^2}$$ So I did: $$g = G \frac{(5.972\cdot 10^{24}kg)}{(6.371km)^2} \Leftrightarrow \\ g = 6.67\cdot10^{-11}Nm^2/kg^...
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3answers
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How are the relative distances of celestial objects from the Earth calculated using observations at a single time instant?

How does one find the distances of celestial objects in the night sky, such as the Moon and the stars, from the Earth using a snapshot of information (including, say, the intensity and wavelength of ...
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1answer
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Why can atmospheric re-entry heat up the air into plasma?

The adiabatic processes of re-entering earth from a spaceship, creates intense heat. Heat in the range of 1700-2000 degrees Celsius. I've read the the temperature in the air molecules generate a ...
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How much at least should the Earth be smaller so that we notice these three phenomenons?

The Earth is moving with a speed of about $1670$ $km/h$ around its axis. This speed is more than the sound speed. So the Earth is always breaking the speed of the sound. How much at least should the ...
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What is the Lowest point of gravity on the Earth map? [duplicate]

what is the lowest gravity point on the earth surface and where is it exactly on the map and what is the importance of having low gravity on earth surface...
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Does Earth's core have a heat sink and does it need one? [closed]

Pardon a question from a complete physics noob. I know only very basic thermodynamics and if my question is completely ridiculous, I apologize. I've heard a very interesting, yet very questionable "...
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Should the centripetal force of Earth's orbit around the Sun affect a pendulum on Earth?

Lets use approximate earth angular velocity around the sun with $\omega\approx2*10^{-7}\frac{r}{s}$ and earth translation orbit radius with $r\approx1.5*10^{11}m$ we can approximate centripetal ...
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Would a 1km edge length solid tungsten cube sink through the Earth crust?

This question was inspired by this question on worldbuilding SE. Suppose you have a giant cube with $1$km edge length made out of pure tungsten and you put it somewhere on the ground. This is the size ...
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How far could one tunnel towards the Earth's core? [closed]

Using current technology and virtually unlimited funds, how deep could we dig a shaft/tunnel with 1m bore (or larger), and what would be the limiting factor(s)? If we push the envelope of current ...
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54 views

What would the surface temperature of the Earth be without the Sun? [closed]

If the Sun would not heat the earth, and never had heated it in the past, its surface would only be heated from the inside. What would be the current temperature of the surface?
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Why doesn't Earth explode from the great pressure inside?

The inside of Earth is very hot, molten, and under incredible pressure. When small cracks form, the pressurized contents spill out and we get volcanoes and eruptions. So does that mean that with a ...
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7answers
13k views

Why isn’t the center of the Earth cold? [closed]

If the pressure of the Earth is keeping the inner core solid, keeping it rigid to take up the least space, and temperature is dependent on how much the atoms are moving, why isn’t the inner core cold? ...
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Generating power with a “straw” to space… Is it possible? [duplicate]

Imagine you have a straw in a glass of water. If you put a turbine inside it somehow and move the glass, pour water in and out of it etc, you would see the water level rise and fall, and the turbine ...
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Black hole on Earth, 1 foot in diameter [duplicate]

If a black hole 12 inches in diameter were situated (say) 10 metres off the ground, what would happen? And how long would it take to devour the earth?
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Closed Room Experiment to prove Earth isn't flat

With Focault's pendulum, it is possible to demonstrate in a closed room that the Earth Rotates with respect to an inertial reference frame. And allowing guests to inspect and manipulate the pendulum ...
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Why does hot air balloon rotate with the earth?

This might be a silly question but I have been wondering this for quite a while. When a hot air balloon is flying in the sky, the earth is rotating at the speed of 1000 mph. Why does it move along ...
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Why cant we measure the alleged curve of ball earth? [closed]

Why can't we measure the alleged curvature of ball earth?
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Can Earth's mass increase due to sunlight? With how much?

Asking this just out of curiosity: I am no physics buff but considering the particle nature of light, each photon has energy (however small it may be). Given this, can the earth's mass increase given ...
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586 views

Determine Earth's radius with stopwatch at sunset [closed]

This question appeared on Bangladesh physics Olympiad 2014, Sylhet, Bangladesh for students of class 9 and 10. I really tried to solve this, but I failed. Please help. Suppose that, while lying on ...
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Variance of earth's rotational speed due to tidal effects

I recently watched a video that explained how the length of the day was impacted by where the Earth was at in its orbit around the Sun. Consider a "day" for a point on Earth the period from when the ...
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Does the length of days change substantially during the year, from more than 24 hours to less?

I just read an article in the 'Science' journal online about Monarch butterfly migration. (Mysterious monarch migrations may be triggered by the angle of the Sun , by Elizabeth Pennisi , Dec. 18, ...
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The net charge of Earth

Shouldn't the earth have an over all small positive net charge? Cosmic rays in the form of light or high energy particles can ionize atoms, when that happens the electron and the positive ion recoils ...
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Change of direction of rotation with change of perspective

Take an apple. Rotate it around its vertical axis to the right (relative to you). If you look at it from above (your head above the apple) and take a point there while the apple is rotating, you will ...
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Is it possible for meteors and asteriods to become natural satellites of Earth?

We know that the moon isn't falling on the earth because it's in orbit. If we make an asteriod or meteor spin is it possible for it to become a natural satellite of Earth?
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Moon is receding from Earth approximately 4cm per year [closed]

According to the theory of relativity the universe is styled as a fabric which is depressed by a large mass and a moon, still following a straight path ever 'curves inward' toward the large mass. Now ...
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1answer
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An asteroid strikes Earth. I’m skydiving. Do I die? [closed]

Let’s say I’m skydiving at a high altitude and, while falling, an asteroid strikes Earth. Is there a certain mass / momentum of the asteroid below which I would have a chance of surviving? Or would ...
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Finding how much time it takes for a complete Earth revolution around the Sun

Long story short, my brother made a joke about how stupid it is to celebrate the Earth making one "trip" around the Sun: New Year's Eve. So I got curious and was wondering: how could the first ...
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Ocean warming by induced electric current for wandering magnetic poles?

In a post on the co-rotation of Earth and its magnetic field (Does the geomagnetic field rotate?), John Rennie raised the point that, if Earth's magnetic field were rotating about its dipole axis, it ...
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Would the moon eventually hit the Earth?

The moon is rotating around the earth in elliptic or approximately circular orbit with speed $v$. Its acceleration have two components tangential and radial one. It is the radial acceleration ...
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Gravitational waves detection using lunar retroreflectors

According to Wikipedia, the wavelength of a gravitational wave is about 600,000 km. The Earth moon distance is about 384,400 km. Considering that the latter is roughly half the former, it seems to ...
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EM waves with frequency much higher than gamma rays penetrate a planet like Earth?

I have just started to study the electromagnetic waves as a personal interest. I wonder if there exist a much higher frequency of electromagnetic wave than Gamma Ray's which can even penetrate Earth. ...

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