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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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Who was the first to realize that the Earth is surrounded by vacuum? [on hold]

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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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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Do we know what Earth 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, do we know what the Earth surface ...
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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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1answer
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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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1answer
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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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1answer
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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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1answer
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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
96 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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3answers
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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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1answer
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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?
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What's a good model for the vernal equinox year? Can it increase forever?

Duncan Steel (2002) makes an interesting argument that the notion of year is (1) somewhat arbitrary and, more interestingly (2) one notion of year can increase while another decreases. His examples ...
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1answer
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Would this effect occur if an ice planet was put into orbit or trajectory? [closed]

Imagine an earth getting warmer. Humans decide to make their homes ready for a voluntary ice age. All the space agencies work together to get an icy planet/moon into our orbit between us and the sun. ...
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How big should be a piece of neutron star to reach Earth's mass?

Imagine a neutron star could be broke into pieces. How big would be the piece matching Earth's mass?
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1answer
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Site to see direction to the Voyager by entering time and coordinates of my position on the Earth? [closed]

Where is Voyager relative to me right now in realtime?
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1answer
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Water Ice on Meteorites

I was reading an article by David O'Brien et al. where it stated "in meteorites only the water bound to the silicates can be found, all the water ice having been lost, whereas on asteroids water ...
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What is Earth's average temperature as a whole? [closed]

I would like to know, what is the average temperature of Earth as a whole planet, not just its surface temperature. Hope the following scenario will make it more clear what I mean: Imagine, that we ...
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1answer
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Why is the shadow of the earth not visible during sunsets?

I would imagine that during a sunset, for a brief moment of time, there would be a shadow of the earth seen in the clouds but I have never seen this. Why does it not happen?
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Calculate eclipse days and duration of satellite

If a satellite is revolving in a GEO orbit, then what will be the eclipse duration for it? How to calculate when the satellite will enter the dark side of the Earth? Any formula or online tool would ...
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How did the solar system get its angular momentum? Why did Earth not fall into the Sun at the start? [duplicate]

I know that Earth is always falling towards the Sun, but due to its sideways momentum it just misses always. But how did it all start? To go into detail, when the gas cloud with zero angular ...
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Simple experimental evidence that Earth revolves around Sun

What are the simplest experiments or calculations that give evidence that the earth revolves around the sun? Can you please explain them and reference the history? Many simple explanations such as ...
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1answer
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Could Earth have been seeded with life? [closed]

The earliest life on Earth is thought to have began shortly after its formation (a few hundred million years after, by fossil evidence, and this while the late heavy bombardment was raging). With the ...
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Why do photos of Earth always have a black background?

if we are in the milky way, and people are able to take photographs from Earth that look like this: Then how come almost all of Earth's photos look like this? In the first photo, we are seeing what ...
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1answer
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Precautions when retrieving material originated from space

I'm assuming that when retrieving a meteor for study and later display, there are precautions taken against possible radiation coming from it. Is my assumption correct and are there other precautions ...
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1answer
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Do we know how old the matter that makes us is?

Last weekend, I had the pleasure of visiting an observatory where there was a series of lectures to cover up the fact that there was too much cloud cover to actually observe much at all. One of these ...
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Why does each and every planet of our solar system have an unique axial tilt angle?

Why do planets have an axial tilt? From the above image we can see that each planet's axial tilt angle varies and differs from the others. What was the cause of this, was this from the beginning of ...
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How to calculate the altitude of the Celestial Equator from an observer's latitude? Exam question

When observing from a latitude of 50 degrees North on Earth, the Celestial Equator will have a maximum altitude of: Answer: 40 degrees I've looked this up and it says something about the observer's ...
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Given sunrise, noon, sunset, longitude and latitude can I calculate the “hight” or “ascension” of the sun?

I'm trying to make a simple app for my own use to be able to check which of my favorit restaurants have outdoor seating sun and for how long etc. Given the data in the title (sunrise, noon, sunset, ...