Questions tagged [earth]

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

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3
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1answer
84 views

Is the equinox absolutely true east everywhere?

I've read that only only in the equinoxes do you get to see the sun rise in the exact east regardless where you might happen to be. However I think this is not absolutely true everywhere, but only in ...
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2answers
1k views

Can you provide a visual description of the sun rise?

The Sun rises in the east only two times a year. The other days, the Sun rises in the east, but a little bit to the north, or to the south. How can you know the degree of how much north or south it is?...
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2answers
76 views

Is a year really 365.24 days, or is it 365.2564 days like I remember?

The NPR News item and podcast Spring Starts Today All Over America, Which Is Weird includes the following: But why isn't the time of the equinox the same each year? The short answer is that ...
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0answers
105 views

Earth circles Sun or opposite? [duplicate]

I've been talking with a friend about our galaxy and mentioned that our planet (earth) circles the sun. He said that it is not necessary to say so, and added that this claim is not stronger than the ...
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1answer
938 views

How is an exoplanet characterised as “Earth-Like”?

Which features or characteristics are taken into account to characterize an exoplanet as "Earth-Like"?
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2answers
62 views

How Does Earth Move In Relation To The Stars

In my simulation, I have stars scattered around Earth, all stars are the same distance from the center of the Earth and positioned based on their right ascension and declination like so: I am ...
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2answers
128 views

When was the longest day on record?

The Earth's rotation is gradually slowing down. It was significantly shorter in the prehistoric past, but now we need to add a leap second every few years and we've not yet had to take any back. In ...
5
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1answer
138 views

Was the Earth-Sun distance ever calculated based on the time difference between night and day?

If we define sunrise and sunset as the time when the center of the Sun goes over the horizon then day time is a little bit shorter than night time because from a single point one cannot see a complete ...
3
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1answer
89 views

Are Sun-Earth L1 & L2 points generally considered outside the Earth's Hill Sphere?

This image from Wikipedia of the SE Lagrange points and the Hill Spheres suggests that the SEL points are outside the Earth's Hill Sphere. (The Hill spheres are the circular regions surrounding the ...
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68 views

What's the first written record of the moon being tidally locked to the earth?

I couldn't find references as to who first noticed (wrote down) that the moon was tidally locked to the Earth. This, to me, doesn't seem obvious from first glance, and looks like something only found ...
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1answer
138 views

If the earth lost 1/81th of its mass how would it orbit change? [closed]

If a planet becomes lighter, then I believe its orbit will change. For example, the moon is 1/81 of the mass of the earth. So, if the moon disappeared, then the earth-moon system would lose 1/81th of ...
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1answer
73 views

Earth as a grain of sand

If Earth was a grain of sand in Buenos Aires in what point in this observable universe map would be LA be?
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60 views

Where and when will someone on Earth be standing with the floor parallel to the Ecliptic plane?

I have been trying to figure this out and I think the answer might be - once per day for anyone living on the Tropic of Cancer or Capricorn. Is that right? To be clear - I want to know where on Earth ...
6
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1answer
101 views

What methods can high school students use to measure the radius of the earth?

I suppose they could split into 2 groups and use the shadow method from different latitudes. Maybe they could also use the stars on the horizon at two different latitudes. Is measuring a ship below ...
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1answer
79 views

What is the exact time of sun stay in each zodiac every year on sidereal year duration?

I tried to reverse engineer from astro-chart times at which sun stays in a zodiac. Here is the list. ...
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2answers
4k views

Why are perihelion and the shortest day in the northern hemisphere different?

The orbit of Earth is elliptical and the nearest distance to sun is perihelion position. Should it not be the shortest day in the northern hemisphere?
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1answer
70 views

Age of earth relative to other planets

Relative to the average age of other known planets, is the earth young, old or in the middle? Does it make a difference if you compare the earth against nearby planets (say < 500 LY), or other ...
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0answers
55 views

Orbitally convenient Mars-to-Earth transit times?

Are there any peculiar solar system layouts that would result in highly efficient transits between Mars-to-Earth? I am aware of a Hohmann transfer orbit, but can other planets be used to "sling-shot" ...
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40 views

Astronomical events and Celebrations

In the past people celebrated important astronomical events and some of those events are still celebrated in some cultures and traditions. For example: March/September equinox, New Moon, Winter/...
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1answer
341 views

What would the effects on or around Earth if Betelgeuse went supernova?

There's been a lot of news lately about Betelgeuse possibly exploding sooner than perhaps was expected. Some examples: Guinan, Edward F.; Wasatonic, Richard J.; Calderwood, Thomas J. (8 December 2019)...
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3answers
229 views

Difference in gravity on both sides of the moon

How much (if any) difference in gravity would you feel if you are on the surface of the moon and: standing right 'under' earth (exaclty between the moon and the earth) and on the opposite side of the ...
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3answers
143 views

How long is the Sun closer to Earth then Mars is?

A recent question at Space.se has generated a few comments that are interesting. But the answer to one particular comment to might address a lot of misconceptions. I imagine the actual halfway ...
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1answer
91 views

Latitude of given altitude of Sun

From Question #6 of USAAAO First Round 2018 (1 point) For the following problem find the range in which the answer lies: on the day of summer solstice, on which geographic latitude is the sun ...
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1answer
147 views

Why do the magnetic field lines of the earth go from south pole to north pole?

I saw these figures and could not get why the magnetic field lines are not pointing from the north pole towards the south pole but they do the opposite. Or also this picture which is about magnetic ...
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1answer
108 views

Earth's magnetic field vs. refrigerator magnet

According to this article: The Earth's field ranges between approximately 25,000 and 65,000 nT (0.25–0.65 G). By comparison, a strong refrigerator magnet has a field of about 10,000,000 ...
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1answer
95 views

Solar degrees vs Calendar days [closed]

What is the difference between solar degrees and Calendar days. Is there any formula to convert one to another. for example Starting from 1/1/2000 1/1/2000 + 300 calendar days=some date (easy) 1/...
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Simulate earth, moon, sun constellation with dates

I would like to simulate the three object distance, specifically the distance of the moon to both, sun and earth for further investigation into tide prediction. What would be a good starting point ...
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40 views

Reason for Orbital Reflector [closed]

We know that last year, space X rocket took orbital reflector with it into the space. But what might be the reason behind launching this weird object into the space? Does it do any work there?
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1answer
78 views

How is Earth's gravity modelled?

The Earth does not have a defined geometric shape. Then how do space scientists who want to put a satellite in orbit model the gravitational field of Earth? Do they assume a single object with minute ...
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2answers
87 views

Does the Lagrange L1 point have a 'size'?

Like in cubic kilometers, what is the size of L1 "area of influence"? being unstable I guess that size can vary?
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3answers
224 views

When did people discover that the Earth is not an ideal sphere, but a little flattened?

When did people discover that the Earth is not an ideal sphere, but a little flattened? And if you know, who was the first person to discover it?
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1answer
107 views

Storm on Earth vs. storm on Jupiter?

Why is the storm on Jupiter much stronger than storms on Earth and why don't the storms on Earth get as big as Jupiter's great red spot
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29 views

Angle of the Sun during winter solstice

What is the angle of the Sun on the eastern horizon at 35° latitude if it is the winter solstice?
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4answers
171 views

What is the size of the largest asteroid orbiting the Earth, other than the Moon?

It seems odd to me that no other asteroid around the Earth is even close to the size of the Moon. Anyone have any idea about the size and orbit radius of Earth's "second moon" ?
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1answer
88 views

Perihelion dates and parameters

I have to find the perihelion and aphelion data for the 20th century for Earth. I found this table http://www.astropixels.com/ephemeris/perap2001.html, but no such table for the past century. I ...
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2answers
120 views

Are there any planets or objects orbiting in Goldilocks zone?

I was wondering whether there were any objects that orbit the "goldilocks zone" besides our home planet earth, and how the goldilocks zone of our solar system is defined.
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1answer
92 views

How Long Will Earth's Year be When Our Sun Goes Red?

We live in a planet that orbits 93 million miles from a G-type main-sequence star, or "yellow dwarf". That is far enough for a revolution of 365 days. Such is the case of Kepler's Third Law of ...
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1answer
149 views

Is it possible that Venus was once a rogue planet? [closed]

As Venus rotates in clockwise direction, while other planets rotate in anti clockwise direction: Is it possible that Venus was once a rogue planet?
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2answers
109 views

Does the magnetic field of earth restore?

The magnetic field of earth protects us from solar wind as we know it, but after the solar wind interacts our magnetic field. Does the magnetic field of earth restore after it deflects the solar ...
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2answers
245 views

Can an Earth-like planet survive if our Sun went Supernova?

First, I would like to point out, yes, our sun does not have enough mass to be a candidate for Supernova, this is a scenario were our sun is though, and after the various life cycle stages of the sun ...
6
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1answer
98 views

Why do transits of Earth across the Sun seen from Mars follow a pattern of occurring after 26, 79 then 100 years?

According to this answer transits of Earth across the disk of the Sun as seen from Mars: The (Arthur C.) Clarke story is quite correct. Earth (and Moon) would transit the sun from the viewpoint of ...
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1answer
95 views

When and where are we exposed to most cosmic radiation?

I understand the mechanical dynamics of being faced away from the Sun at night, having a lower altitude, not being in the weak points at the poles in the atmosphere, being in a valley and others ...
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3answers
3k views

How well would the Moon protect the Earth from an Asteroid?

Would the Earth fare better if the Moon blocked the meteor, comet, rogue planet, or otherwise rather than a direct impact? At what point would the Moon's debris would be an extinction event? The ...
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1answer
82 views

Earth's perihelion vs winter solstice [duplicate]

I found that Earth's perihelion occurs roughly two weeks after winter solstice similar thing happens for summer solstice and aphelion. I understand what those terms mean but I don't understand the ...
6
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1answer
195 views

When did the first annular eclipse happen?

A few hundreds of millions of years ago, the moon was closer to the Earth than it is today and hence was of a bigger apparent size. This made every solar eclipse either total or partial. Over the ...
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4answers
219 views

Could the solar system survive in a void?

If the solar system were suddenly placed in the middle of a large void... would everything still function as normal? Would we even notice any difference here on Earth apart from the night sky? ......
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3answers
93 views

What effect does Earth losing a part of its mass have, is there an impact on the Earth's orbit around the Sun?

This is a random question that popped into my mind. I'm not a physicist or astronomist, however, I am genuinely curious. Also, this is not intended as a science fiction question, but an actual science ...
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1answer
143 views

What keeps the planets of the solar system moving in their fixed orbits?

Models of the solar system show each planet moving around on its own orbit. Is is really because of the Sun that every planets remains in its own fixed orbit?
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132 views

Can someone tell me what is exactly the curvature per mile in earth? [closed]

Earth is a planet as we all know.Astronomy examine the planets too.So whats the point looking for answers on other planets if you cannot give an answer to a simple question like the following. Basic ...
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4answers
258 views

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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