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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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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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What is the Structure of Earth's atmosphere?

What are the Structure of the atmosphere of the earth and what is the difference compare to other planets ?
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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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1answer
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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 is the core of Earth in a reduced state? ($\text{Fe}$ and $\text{Ni}$) [migrated]

I understand gravitational differentiation caused the layered structure of Earth when it is still molten. However, why are the heavier constituents in a reduced state, i.e. metal $\text{Fe}$ and $\...
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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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1answer
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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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1answer
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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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1answer
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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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1answer
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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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1answer
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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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1answer
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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-...
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In astronomy Is there a name for the exact time between solar noon and sunset?

Like there are names for various events such as sunset, sunrise, solar noon, solar midnight, astro, nautical and civil twilight, what exactly is name for time between sunset and solar noon. Afternoon ...
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If a giant object would approach the Earth, would Earth start to turn faster or slower while the object starts to become nearer and nearer?

I am asking myself this question: if a giant celestial object would approach the Earth, would Earth start to turn faster (then day duration would be diminished) or slower (day duration increased) ...
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Why does earth's north pole roughly point in the same direction throughout the year?

I know there is a gioscopic explanation but I was under the impression that Earth is traveling in a straight line through space that has been curved by our sun's gravity ,so my question is why doesn't ...
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Just out of curiosity. What's this curvature per unit length for a sphere? I see a lot of flat earthers using it.

I've seen most flat earthers mention if earth was a sphere the earth should curve at x value per unit length. Is that even a proper logic? Radius of curvature is constant for sphere and a circle of a ...
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Can one detect from earth that angular momenta of its axial rotation and its orbital rotation are “almost parallel”?

I mean that the angle between these angular momenta is acute as opposed to obtuse (23.5 and not 180-23.5), so that the rotations are "roughly in the same direction". Related but distinct question -- ...
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What does it mean that the Sun`s rotation axis is: RA 286.13° , Dekl: 63.87°?

first post here. I found 1 related Question, which has not solved my Problem. SHORT QUESTIONs VERSION: Suns axis is 7,25° tilted from the ecliptic. But in which direction? LONG QUESTION: Nasa ...
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1answer
110 views

What cosmic disaster is most likely to happen? [closed]

Of all the different ways that the Earth can be destroyed what ways is the most likely that could happen?
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Calculate position of the Sun in ECEF

I'm making a very basic orbit simulator in C# using the Helix Toolkit. I want to position the Helix lighting object at the sun, but also be able to calculate solar eclipse by the moon and earth for a ...
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Could the Moon sit on the Earth?

Let say that the Earth's Moon was knocked out of orbit and landed on the Earth with some damage but not world ending. Would Earth's atmosphere envelop to include the Moon? Would the moon sink into the ...
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What is the Terra phase?

Does the Moon have a night and day like Earth? When sitting on the Moon and viewing the Earth what does it look like when the Earth goes through phases like the Lunar Phase? How does the sun travel ...
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Reversal of magnetic poles of earth

When the magnetic poles of the earth get reversed, does the earth keep on revolving in the same direction or does it start revolving in the opposite direction?
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How much magnetic attraction is there between the Sun and Earth?

How much magnetism is there between the Earth and Sun? Would the distance from the Sun differ for not the Earth iron core and how much?