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Questions tagged [earth]

Questions regarding the planet on which humans live; the third planet from the Sun.

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Origin of heavier elements on earth?

Earth is part of Solar system, which is said to have originated from condensation and mutual attraction in dense clouds of gasses and dust. If Sun is basically more than ninty percent hydrogen and ...
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Orbital decay of the Earth's orbit and Earth's moving closer to the Sun

If we consider orbital decay of the Earth's orbit, then can we counter argue with the following reasons? Due to tidal effects transferring small amounts of angular momentum from the Sun's spin to ...
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Word for blue ring around the Earth

From certain positions in outer space the Earth will appear to have a blue ring around it when the viewer is in the shadow of the Earth and sunlight is passing through the atmosphere. Here is a ...
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Does the sun have cycles causing temperature changes on Earth?

Can the Sun go through seasons or cycles to cause a temperature change? Could the Sun have to go through any kind of thermal cycle to change the climate on Earth and by how much?
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How to caclulate the chinese Three Gorges Dam impact on Earth rotation? [closed]

According to this January 2005 NASA JPL News item NASA Details Earthquake Effects on the Earth, the Three Gorges Dam has slowed down Earth's rotation by 0.06 microseconds per day. Having that weight ...
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Are these real paths of planets as traced from Earth?

Few days a go, I came across these two pictures of paths of planets as observed from Earth. They have a perfect geometric shapes. Actually, to me they look so beautiful and perfect, that they appear ...
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Why is the equinoxes only 2 days and not more?

The earth is tilted at 23.5 degrees which means that in the solstices the north/south hemisphere is more radiated by the sun and the tilt to the sun is maximum. In the equinoxes, the tilt is not ...
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Diamonds in Neptune?

In this publication from 1981, was shown that Neptune is raining diamonds: Many of the current models of Uranus and Neptune postulate a three-layer structure, consisting of an inner rocky core, a ...
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Seasonal effect based on Earth position [duplicate]

I know that Earth rotates around the Sun in an oval route: And I know the seasons happen, because the axis of the Earth is not vertical. I think it is 23 degree slope. How come the distance from the ...
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Why is Earth's rotation considered fast?

I'm currently reading Atom (Krauss book), and in chapter 11 there is this text: This collision can explain many things, including the high rate of spin of the Earth (the grazing collision would ...
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If Earth is tilted, why is Polaris always above the same spot?

Why is Polaris, the North Star, always above (or near) the North Pole? If Earth is tilted, Polaris' path should be in winter 23 degrees away from its path in summer, or not?
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Should the sun appear very low in the horizon if its path is always between the two tropics?

If the sun never rises above the tropic of cancer and never goes bellow (southern) of the tropic of capricorn then it seems that it should appear to the observer lower and lower in the horizon for as ...
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What is the origin of the term “plane of the spirit level”?

I have heard the term "plane of the spirit level" e.g. the sun's shadows is X degrees to the plane of the spirit level to signify the surface of the earth and I see it is a common term used in ...
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South of the tropics, where does the sun's noon shadow point?

If I understand correctly, in countries to the north of the tropics the sun's noon shadow points north. What happens south of the tropics? Is it pointing south?
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Historical Day Lengths on Earth

I recently read something about a major earthquake in Japan having possibly shortened Earth's day due to an increase in rotation. Here's an example: https://www.nasa.gov/topics/earth/features/...
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Why hasn't the Earth fallen into the sun yet?

So the Earth's been orbiting the sun in a relatively stable orbit for billions of years now. during that time, it's been plowing through dust, and hit by comets and asteroids, presumably mostly from ...
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Why is the Earth called terrestrial? Can we call the Earth an ocean planet?

Why is Earth called a terrestrial planet even though it is 70% covered by water?
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Did the Moon ever approximate a geosynchronous orbit above the early Earth?

Simulations suggest the early Moon formed about 20,000 to 30,000 km away from Earth which is less than the current geosynchronous orbit of 42,164 km. The Moon is now 384,000 km away from Earth. Does ...
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The equation for calculating how many times Earth (or our solar system) has revolved around the Milky Way

I have seen it said on Quora and Reddit that it's about every 220-250 million years to go around the Milky Way from Earth. Wondering what the rough equation is for calculating it. That is, I guess, ...
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Angle between earth's angular momentum and earth's axis

I think this picture is correct because for earth astronomical day is slightly shorter than solar day. (Is it a rule of thumb for planets? Where can I read such data?) Source So the angle between ...
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What will be the temperature on Earth when Sun finishes its main sequence?

We know that presently Sun is 4.5 billion years into its main sequence. It has another 5 billion years before it enters the Red Giant phase. We also know that Sun's luminosity increases by 10% every ...
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Why are there no stars visible in cislunar space?

It’s very puzzling that the moon landing had no stars in the background, the ISS clips have no stars in the background. I listened to multiple astronaut interviews speak on what it looks like up in ...
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How far does the Earth travel around the Sun during each month of the year?

After reading about the Earth's orbit and how it moves faster in January than it does in July (based on its distance from the Sun), I started to wonder... How far does the Earth travel around the Sun ...
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Why is the moon drifting? Shouldn't orbital decay bring it closer? [duplicate]

I noted that the moon drifts away from Earth a few centimeters each year. However, I'm thinking that the emission of gravitational waves would deter such thing and cause the exact opposite. ...
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Official degrees of earth’s rotation per day

What is the official degree to one decimal point please, of the earth’s rotation in one single day. Can it be confirmed that it is exactly 360.0 degrees using official data? Thank you in advance.
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Is the moon inside earth’s atmosphere? If so, what are the consequences?

Recently, a paper was published claiming that the Earth’s atmosphere extends far beyond the Moon. This has been reported on by a number of news sources and websites, including the ESA, Business ...
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Angular diameter of the Sun's reflection from the ocean, seen from Sun-Earth L1?

I'm trying to understand how smooth the reflecting ocean surface would need to be to produce such a small bright spot as seen from the DSCOVR satellite at Sun-Earth L1. It appears to be only about 8E-...
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Are there pictures from a solar eclipse of the earth taken from a moon landing unit or orbiter?

Did any moon landing vehicle or orbiter took pictures of a solar eclipse happening on the earth, i.e. the moon's shadow on the earth? (Alternatively from other spacecraft showing the whole globe). A ...
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Can Earth be ejected out of the solar system this way?

I found this image of what maybe a model of our solar system. Without a credible source I'm not sure I am looking at a star or black hole that comes close to our solar system and how it could throw ...
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Who was the first to realize that the Earth is surrounded by vacuum? [closed]

My question isn't about the arrangement of planets in space (geocentrism / heliocentrism), nor the understanding of the whole universe (we are in a galaxy, there are galaxies etc). My question is: who ...
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What's the proportion of Mars' surface compared to Earth's surface uncovered of water?

How does Mars surface compare to Earth's surface? Mars is quite smaller than Earth, but most Earth's surface is covered with water. I thought making the math could be relatively easy but Earth isnt a ...
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How close to circular is the Earth's equator

Earth's orbit is about 99% circular. How circular is Earth around the equator? I know it bulges around the equator and is a spheroid. I also know it is not smooth and has oceans and mountains and all ...
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How are cardinal points on horizon defined?

How are the cardinal points (North-East-South-West) defined? On equatorial regions it is somewhat obvious. But what about the higher latitudes? If the pole star is up above the sky instead of horizon, ...
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What would happen to the solar system if Earth's mass was removed?

This question is inspired by the "Stargate SG-1" episode "The Road Not Taken". In that story a device is used to shift the entire Earth to another dimension to defend against an attack. I'm not ...
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What is Earth believed to have looked like before the collision with Theia?

Let's assume the moon was formed because Earth collided into Theia. (There are numerous other theories, but this one is the most widely accepted.) In that case, are there theories that address what ...
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Properties of low-mass stellar remnants vs the Earth

How does the Earth differ from a (low-mass) stellar remnant, which has stopped fusion and the outer layers of which have been blown away? Could a stellar remnant end up with a similar relative ...
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Could a rocky rogue planet get trapped in the orbit between Earth and Mars?

I know it's extremely unlikely a rogue planet passing by there, and I know the size of rocky planets can vary a lot (IIRC there is a rocky planet 5 times the size of Earth) but in any hypothetical ...
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Change in axis of the Earth if the Moon would dissappear [closed]

I read that, if the moon would not be there or if it would dissapear or be destroyed it could cause the earth to rotate into a possible axis of 45° degrees. Because it would be missing the ...
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What causes Titan a moon to have a denser atmosphere than that of a Mars?

I'm wondering about Mars and Titan. If Mars is larger than Titan how come it lost most of its atmosphere? Mars also has a magnetic field while Titan doesn't. Yet Titans atmospheric pressure on the ...
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Will Earth at some point stop rotating anti-clockwise, stay still, and then rotate clockwise? [duplicate]

Will Earth at some point stop rotating anti-clockwise, stay still, and then rotate clockwise?
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Do we know if there are asteroids leading or following Earth in Earth's orbit around the Sun?

A search of the Internet is so clouded with discussions about the asteroid belt or asteroids orbiting the planet Earth that I couldn't see an answer to my question. Do we know if there are asteroids ...
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If Earth suddenly stops rotating, will be thrown at 465 m/s? [duplicate]

If Earth suddenly stops rotating, will be thrown at 465 m/s ?
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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?

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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Earth rising and setting from moon's perspective

Why the earth is rising and setting seen from the moon, when the moon is tidally locked? Shouldn't the earth be always on the same spot because of the tidal lock, if observed from the moon?
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Is Earth's true anomaly roughly 1 degree currently?

I wrote software which uses GMT real time to calculate Earth's mean, eccentric, and true anomaly. I encountered a bug where after reaching 360 degrees, instead of flipping back to zero, it subtracts ...
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Why is the moon more visible during the winter? [closed]

I was curious to find out that as to why, the moon looks more sharper during the day in winter, whereas it's almost not visible during summer.
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What was earth's mass before the collision with theia?

Assume the "Big Splash" or "Giant Impact" (whichever name you prefer) theory is more or less correct. EDIT: With so many variations of this theory, with so many names and qualifiers on them, such as ...
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Gravitational acceleration inside a planet

The gravitational acceleration, g, inside the Earth generally decreases with decreasing distance to the center: However, apparently for Jupiter, the gravitational acceleration only increases with ...
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Which direction does the Earth face as it travels through the Galaxy

According to the Helical model, as the Sun orbits around the galaxy, the planets that orbit the sun are travelling perpendicular to the path of the Sun. This is better shown in this video: https://...
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How long will a ball of ice stay in orbit around Earth? [closed]

How big would a ball of frozen water need to be to last one orbit? How would atmospheric drag effect the ball of water? https://space.stackexchange.com/questions/32188/what-is-the-darkest-orbit-...