Questions tagged [earth]

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

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1answer
161 views

What contributes the most to the seasonal temperature variation?

The seasonal temperature is ultimately due to the precession of the Earth around the axis. But what I'm curious about is... is it due more to the side experiencing winter being farther from the sun ...
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106 views

Can we, with arbitrary precision, calculate what's the place on earth that's closest to the sun on a given day?

Can we, with arbitrary precision, calculate what's the place on earth that's closest to the sun on a given date? If so, what's the math like? Say, if I wanted to calculate this within 1m, 10cm or 1cm ...
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2answers
191 views

What kind of a visual trajectory would an asteroid have if it were to hit Earth?

Let's say that Peter has a set of superb telescopes and he's watching the sky every night, for 3-4 months. He may not know it just yet, but there is an asteroid heading towards Earth, on a crash ...
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1answer
6k views

If an asteroid was to collide with Earth, how much warning would we have?

I was talking to my 9-year-old son about the Florence asteroid that is passing close to the earth. He wanted to view youtube videos about that asteroids, and we saw the starting of this one https://...
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1answer
278 views

Why do we we even exist? [closed]

It came to my mind one day that why does this universe even exist and why do we even exist and like we are enclosed in the so called atmosphere and a floating rock in space called the Earth, so is ...
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1k views

On the Equator, why are the shortest shadows seen at 11:32, and not at Noon?

On Equator, why do objects cast the shortest shadows at 11:32 and not 12:00? For instance, this happens in Costa Rica.
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1answer
102 views

GEO and HEO images of Earth

I would like to see some GEO and HEO images of Earth. But I can't find a good source. There are a lot of LEO images of Earth but I can'f find any raw images from higher (preferably 30,000km+) ...
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1answer
160 views

Why would there be no day/night cycle even though the firmament would still be rotating, according to Copernicus

In chapter 6 of "The Revolutions of the Heavenly Spheres" where Copernicus maintains that the heavens are immense compared to the size of the Earth, the Edward Rosen translation of the book states ...
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2answers
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How did we first determine the Earth's departure from sphericity?

I'm quite interested to know the history of the study of the Earth's departure from spherical symmetry. What were the first methods used to model the non-spherical geometry of the Earth? For example, ...
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64 views

Earth shape and rotation

Imagine a helicopter that took off from point A and goes vertically in the air to a certain fixed point B in the atmospheric area at a certain fixed altitude with enough fuel to stay there (at point ...
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1answer
658 views

How long was an early Earth year? [duplicate]

Roughly how long did it use to take for the early Earth 4.5~ billion years ago to complete one revolution around the Sun? (I know the Earth was spinning much faster, so a day would only take 2-3 ...
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455 views

If a comet strikes a glacier, does it make a print on the land below?

The Younger Dryas Impact Theory describes an asteroid impact in Northern America, possibly the eastern part of Hudson Bay, which contributed to the end of the last ice age. If a comet strikes a ...
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1answer
146 views

How have we measured the radius of the Earth (old and new)?

I'd imagine ancient methods are fun exercises in geometry. how has the measurement has evolved over time? The first method is credited to Eratosthenes. He knew that during the summer solstice in ...
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1answer
119 views

How are the elevations of the poles proportionate to distances of earth that have been traversed according to Copernicus

In chapter 2 of "The Revolutions of the Heavenly Spheres" where Copernicus maintains that the Earth is spherical, the Edward Rosen translation of the book states that the elevations of the poles ...
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2answers
449 views

Which would be safer: removing hydrogen or adding hydrogen to our sun?

If we want to extend the lifespan of our habitable zone safely, would it be safer to institute a yearly 'tax' on our suns outer layer of hydrogen, or a yearly 'subsidy' to our suns outer layer of ...
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1answer
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How can I calculate the time between sunset and actual darkness?

I would like to know the time it takes to go from sunset to dark based on GPS location. In addition, ideally I would also like to have a formula that determines the percentage of sunlight at each ...
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2answers
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Size and Mass of a typical “small” asteroid that impacts the Earth?

I'm looking for some realistic data about the size (in meters) and mass (in kg) of a typical small asteroids that impact the Earth, without disintegrating in the atmosphere. Any suggestion ?
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914 views

Umbra, penumbra and antumbra

I'm trying to understand following schema of the wikipedia page here. Image subtitle is "Umbra, penumbra, and antumbra, for a lunar eclipse". Distances and sizes are not to scale. If distance ...
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3answers
200 views

Problem about orbiting of a satelite

Problem: There is an satellite that orbits the Earth. Its orbit is circular and its orbital plane is perpendicular to Earth's Equatorial Plane. It orbits is such that a person who is on equator see ...
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1answer
243 views

How far away does the Moon have to be until Earth doesn't feel its effects? [closed]

How far in miles does the Moon have to be for the Earth not to feel its effects?
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611 views

Calculating length of summer solstice day using tilt and latitude

I want to be able to predict how long the summer solstice lasts at any part of world given the maximum tilt angle $φ = 0.4101524 \; \mathrm{rad}$ and the latitude $θ \; \mathrm{rad}$. I specifically ...
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2answers
456 views

Which constellation would appear to revolve around Denab,Vega or Thuban when axis of the earth would point toward them?

We have been calling the star by looking at which we can make out the direction of the North Pole the North Star. This was the only method at the disposal of the sailors during the days when they did ...
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1answer
263 views

Stellarium simulation

I'm interested lately in Stellarium and the functionalities which it provides especially scripting. I want to make a simulation that shows the celestial sphere with some planets like Venus, Mars, and ...
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1answer
114 views

Hole through the earth [closed]

I have a problem: If I would dig a hole through the earth, and jump right in, disregarding the rotation of the earth, I should come back out on the other side. However, orbital mechanics say ...
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2answers
463 views

If there was air between the Sun and Earth, how warm would we get?

Based on this question: How loud would the Sun be? If instead of a vacuum we had air between the sun and earth (let's say of the same composition we have here on earth) how warm would our planet get?
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4answers
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About how many revolutions has the Earth made around the sun?

The Earth is about 4.543 billion years old. However, the length of a year can be changed by anything from an impact to a natural cycle of orbit changes to a slow drift toward or away from the sun to ...
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2answers
488 views

As the Sun dies, does the Earth's orbit change?

As the Sun nears the end of its life and expands, would the Earths orbit get bigger as it moves out or would it stay in the same orbital plane and not move out? Therefore in the far off future, we'd ...
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1answer
462 views

Can Earth have a ring?

Why doesn't the earth have a ring? If solid material such as dust and moonlets, and common components of satellite systems are brought nearer to the Earth, then what will happen? Will it take the ...
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1answer
794 views

If earth changed its orbit, what would happen to the moon?

Let there be an accelerating force acting on earth over an arbitrarily long time to change its orbit around the sun (e.g. by asteroids repeatedly passing by close to earth (intentional or not) or ...
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3answers
906 views

Determining latitude and longitude in bad weather

In Sobel's famous book 'Longitude', she described the story of Harrison. I still have one question. What if it is cloudy on the sea? In this case, the sailors have nothing to compare with, right? This ...
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1answer
2k views

Could an object block out the Sun from Earth's view for 3 hours?

how large, massive, far away (from earth), and fast would an object (planet-like) have to be to block out the Sun for 3 hours and not disturb Venus, Earth, or the Moon?
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494 views

Why does the traslation movement of the earth last the same time as the four seasons?

Why does the traslation movement of the earth last the same time as the four seasons? The seasons could take 100 days or 200 or 20 years (aprox. like in GoT)... but exactly (exactly???) 1 year. Why? ...
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1answer
82 views

Age of a planetary body

We quote that the Earth is about 4 billion years old. However earth started with billions of cigarette smoke sized particles. What event or size or something do we use to say this is the start of ...
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2answers
916 views

What causes the Earth to have gravity?

I've always wondered how our planet Earth or any other large spheroid-shaped thing in our universe has gravity? Does it have a small black hole on its core causing it to have gravitational force? ...
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2answers
3k views

Transformation from Geocentric Coordinates into Equatorial Coordinates?

I have the moon's position in equatorial coordinates (RA and Dec) and now I want to calculate same moon's position in terms of earth centered coordinates i.e. Geocentric (latitude & longitude). My ...
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1answer
1k views

'Very High Noon' - Sun directly overhead

Twice a year the sun is at a certain angle south (or north) of the equator between The Tropic of Cancer and The Tropic of Capricorn. At that time the sun will be exactly overhead for people at the ...
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195 views

What would be the difference in distance between earth and moon on supermoon night (14 November 2016)

As we all know the usual distance between earth and moon is 384,400 km. But i was thinking how much closer it will be on 14 November 2016, as it will be a supermoon, the brightest and biggest moon in ...
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1answer
7k views

Is it same distance Equator & Prime Meridian? [closed]

i just want to ask in earth what the difference between Equator & Prime Meridian & also want to know is it same distance Equator & Prime Meridian?
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2answers
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Distance to Sun at Perihilion and Aphelion at max and min Eccentricity

Title says it all. I'm putting together a presentation on Milankovitch Cycles, and I would like to bring up the difference in distance to the sun (km) at aphelion and perihelion when the earths orbit ...
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1answer
3k views

Will the Earth ever be tidally locked to the Moon?

From my basic understating, Momentum is being transfered from the Earth's rotation to the Moon's orbit by tidal friction. The Earth's rotation slows down and the Moon receedes from the Earth as it ...
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3answers
2k views

Sudden Effects of Sun Disappearing [duplicate]

It takes 8 minutes for the sun's light to reach earth. If the sun were to instantly disappear, what would happen? I imagine that Earth would fly away on a path tangential to its orbit. What would ...
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4answers
4k views

Did the earth form outside the solar system?

Why isn't it possible that the earth formed outside the solar system and got attracted later by the Sun? I just need arguments to defeat this hypothesis.
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1answer
236 views

Energy deposition in planet Earth due to gravitational waves

The gravitational wave detected by the LIGO observatory acted on planet Earth streching and shrinking it a little bit. I assume that not all of this action was fully elastic and that some energy of ...
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2answers
772 views

Can Earth host another natural satellite than the Moon?

Are there orbits with long-term stability (astronomical time scales) around Earth? Low altitude orbits will decay due to friction with Earth's atmosphere. Inside Earth's Roche limit, a Moon could not ...
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1answer
609 views

What makes the Earth infinitely rotating around its axis

I was reading two sites before I posted the question here. One site says something like that the collisions in Universe eventually set the planets rotating, another site says that our planet is formed ...
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1answer
94 views

Measurement precision of celestial events

The local weatherman declared that fall starts at exactly 10:21am (local time). Ignoring the fact that seasonal boundaries have multiple definitions (meteorological, astronomical, etc.), what he ...
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1answer
572 views

The Hollow Moon Story [closed]

I've heard on various programs (yes TV) with "supposed" experts in various fields that there is evidence which would suggest that the moon could be hollow. The experts ranged from scientists, sound/...
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1answer
483 views

Effects of the solar tide on planets

It’s well known that (lunar) tides on Earth result in a transfer of angular momentum from Earth proper to the Earth–Moon orbital motion. That’s why the Moon resides now in a high Earth orbit, and ...
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1answer
893 views

Angles of sunrise and sunset viewed from a surface anyway oriented

I need to understand how to calculate the angles of the sunrise and sunset viewed from a surface oriented against the azimuth and the horizon plane, and for any day of the year. For example, I have ...
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1answer
55 views

Observations of a perigee coincident with a full Moon

Hopefully this will be a quick and easy question, with a quick and easy answer, but why is it that we observe a perigee Moon coincident with a full Moon approximately every 13 months? Is this related ...

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