Questions tagged [earth]

Questions of the science and space exploration related to Earth.

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25
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3answers
5k views

How are astronauts in the ISS protected from electric shock?

On Earth, most of the electrical appliances having exposed metal parts, such as electric iron, are grounded, to protect the user from electric shock when an uninsulated-wire accidentally comes into ...
-1
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4answers
140 views

What kind of force is there in exact middle of earth? [closed]

Basically i have one question but this question leads to another. firstly can we dig in earth that from one side we reach other side of earth ? i mean just going through it. Now let's say we can dig ...
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1answer
136 views

Can we hang a really large rope or wire from space to the Earth? [duplicate]

I have a very simple question that can we hang a really large wire from space to the Earth? What if we build some turbine kind of thing that can produce electricity in space and we transfer that from ...
2
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1answer
102 views

Which camera has produced this image from Longjiang-2 microsatellite?

Here is an image of this lunar micro-satellite taken in 2018, from this tweet, found in this comment below the question What is the most recent photo taken from the Moon surface as of August 2019? In ...
36
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4answers
14k views

Why is my Earth simulation slower than the reality?

It took me a long time to create a simulation of the Earth like that. I wanted to show the real spinning speed of the Earth. Here's my video: From this NASA live ...
2
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0answers
115 views

Orbiting clock visible with the naked eye

Does anyone remember from the 1980s or possibly early '90s in the UK news a (serious) story about contructing a huge orbiting clock so that people would be able to look up at the sky to read the time ...
1
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3answers
188 views

Is the night sky on Earth different from the night sky on the moon or Mars?

If colonists or space-tourists spend time on the Moon or on Mars long enough to have a chance to take a good look at the nighttime sky, will they be able to see stars and the Milky Way? Will they ...
0
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0answers
56 views

Convert ICRF to Body-fixed coordinate for Earth or Lunar. (MATLAB)

I want to find the position (x, y, z) of the satellite around the Lunar. I use the gradient of the gravitational potential to get an equation of motion of x, y, and z-direction in inertial coordinate. ...
8
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1answer
998 views

What materials are naturally released into space from earth?

I am wondering what kinds of materials that are released by Earth into space due to natural processes. If possible, what are their approximate rates in kg per day or year?
3
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1answer
153 views

Have there been any spacecraft with an ecliptic Earth orbit?

Have any spacecraft (manned or unmanned) orbited the Earth in the same plane as the Sun? (Please read the question carefully. It is not an orbit centered around the Sun, nor an equatorial orbit.)
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1answer
81 views

What types of engines are able to go from Earth orbit to Martian orbit? [closed]

What engine is the most efficient in fuel and/or time to go from Earth orbit to Mars orbit and back again that are not capable of launching from the ground?
1
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0answers
67 views

Question about line-of-sight on a flat earth [closed]

If the Earth were flat - could you (on a crystal clear day) see the Himalayas from the UK? (Assuming there were no obstructions in between) And secondly - would the view into space be any different?
4
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1answer
241 views

Are we changing Earth's rotation?

Can rockets launching change Earth's rotation, and can going into orbit do the same?
5
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1answer
254 views

Is it possible to take another Pale Blue Dot image?

Pale Blue Dot is a photograph of planet Earth taken on February 14, 1990, by the Voyager 1 space probe from a record distance of about 6 billion kilometers (3.7 billion miles, 40.5 AU), as part of ...
4
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2answers
723 views

Why is the earth so small when observed from the moon?

I recently discovered the pictures from DSCOVR taken at the Lunar Transit in 2016. The earth appears very massive behind the moon, which is a little unintuitive if you consider how small it is when ...
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0answers
37 views

Can Voyager I be turned around? [duplicate]

This video discusses the looming death of the Voyager I. Is it possible for the craft to be reprogrammed, thus making its way back to earth?
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9answers
12k views

Which country borders are visible from space?

You can see the borders of North Korea with China and South Korea at night from the ISS since unlike their neighbours, they have almost no light. That got me thinking, which other country borders (of ...
5
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1answer
150 views

At what altitude do the effects of atmospheric drag completely disappear?

The spate of K-questions got me thinking: At what point does atmospheric drag disappear1 with the pressure from sunlight, solar wind, or other forces becoming overwhelmingly dominant? I'm guessing it'...
1
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1answer
96 views

Would a debris field on Mars look like one on either the Earth or the Moon?

I am assuming there are no photographs, with enough resolution, of the any of the debris fields of Mars probes that crashed into the surface of Mars to indicate what the debris field looks like. I am ...
2
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1answer
80 views

Hypersonic Inflatable Aerodynamic Decelerator entry to Mars' atmosphere

Is it known whether or not a Hypersonic Inflatable Aerodynamic Decelerator inflation and entry into Mars' atmosphere would produce more violent vibrations and lateral movements than was experienced by ...
36
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2answers
5k views

Was the “Earthrise” witnessed by Apollo 8 the first available “full” photo of the Earth?

Was the video/photos taken during the earth-rise on the Apollo 8 flight the first "blue marble"-esque photo? I've heard the image equated to the "earth's first selfie" and question the technical ...
0
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1answer
273 views

How long was the trip from Earth to Mars for Insight?

How long was the trip from Earth to Mars for Insight from blastoff to landing?
4
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1answer
180 views

At what point when travelling faster and faster around the earth are you not gonna be falling back again (7km/s? 8km/s?)

My dad and I thought about a problem we had when discussing Earth's gravitational field. This wasnt the original question but I still would like to know the answer. So essentially my question is: ...
0
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1answer
89 views

How to match orbital speeds of 2 or more satellites in different orbits?

Satellite ME is orbit around the Moon and Earth. Satellites E is around Earth. I understand the low orbit satellites orbit at higher speeds. Can Sat ME match the speed of any of Satellites E at any ...
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1answer
95 views

How large would a alien spaceship have to be to affect the earths gravitational orbit? [duplicate]

Would a large enough ship generate enough gravity to affect earths course?
5
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1answer
296 views

Is there any life from Earth that can live on Mars?

Does Mars have any environment in which a plant, virus or otherwise would be capable of living on Mars without an artificial environment? Is there anything that can live below the Armstrong Limit on ...
3
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1answer
130 views

Which mission delivered the first ever complete photograph of the Earth?

So far, I found a picture made from a captured V missile launched in US to image part of the Earth. Which mission did deliver a full view of the Earth from the space? Note. Of course it's ...
1
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1answer
128 views

How much asteroid can we divert from the Earth?

There are many movies with the Earth being saved by sending a bomb out blow up the asteroid. What realistically could we do to that degree today? Do we have interplanetary missiles? if so how much of ...
3
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1answer
967 views

How to calculate GEO (geostationary) satellite eclipse time?

The positions of satellites in geostationary orbits can be characterized by their longitude, the longitude of a point on Earth's equator that is nadir to the spacecraft. Satellites in GEO will ...
0
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1answer
71 views

Can an Earth like planet support life by building a Dyson Sphere across a White Dwarf? [closed]

(Hypothetical Concept) But is it possible to depend on a white dwarf as our power source? Provided we harness its 99% of energy? Can life be sustained?(If it is possible we can easily colonize an ...
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0answers
41 views

If earth span fast? [closed]

Imagine earth spinning at very high angular speed. What it would feel like at various latitudes from 0 to 90 degree ? Like at 0 degree one may feel lighter than his weight. At 45 degree one is going ...
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3answers
406 views

Help computing solid angle subtended by the Earth as seen from LEO

I would need to compute the solid angle of the Earth from a spacecraft when close to the Earth, where no small angles approximation can be made. I thought it wouldn't be that hard but I feel actually ...
2
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1answer
64 views

Plotting error values between simulated and JPL data

I'm attempting to compare values between my simulated data for the solar system and the official JPL data, to find errors for the position, velocity, inclination and azimuth. The simulated data was ...
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2answers
121 views

How do constellations appear to stay constant despite Earth's spin and orbit? [closed]

Our Earth is spinning and also orbiting the Sun, so how do the constellations appear fixed and constant? Almost all galaxies and stars are said to be fixed relative to constellations.
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2answers
194 views

Earth Habitable zone

The question is "Find the maximum orbital eccentricity that the Earth would be allowed to have if it stays in the “habitable zone” all the time. Be careful to define what you mean by “habitable zone""....
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0answers
46 views

Why did DSCOVR increase its pictures rate on February 3rd 2018?

On February 3rd for some reason NASA tuned up DSCOVR to send images of the Earth every 20min instead of the regular 2 hours interval. Last time they did this was for the great USA solar eclipse, in ...
8
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2answers
845 views

Could you launch rocks from the Moon to hit Earth?

In the Robert A. Heinlein novel, The Moon is a Harsh Mistress, the plot famously revolves around sending rocks from the Moon to Earth, launched via electromagnetic rail gun and the impacts looked like ...
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1answer
714 views

Finding the true anomaly

I've read from a page that you can find the distance from the Sun to the Earth via the following equation: $$r = a\frac{1-e^2}{1+e\cdot \cos(θ)}$$ where r is the distance from the Sun, a is the semi-...
3
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1answer
527 views

What's the unshielded radiation dose in mSv in Low Earth Orbit?

Say we have a guy orbiting Earth in LEO with no spacesuit (I know, I know), what would be the millisieverts he would be receiving?
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2answers
426 views

What is the Fischer 1960 Mercury Ellipsoid, and why is it called that?

Don't be distracted by the 1960 Mercury shown below. Reading about Irene Fischer (also here, and mentioned in this answer) and seeing the Fischer 1960 Mercury Ellipsoid turn up in tables of ellipsoid ...
2
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2answers
229 views

Are there any protocols the space station follows if there is an Earth-wide catastrophe?

Are there any protocols the space station (or any space explorer) follows if there is a massive catastrophe on Earth where the responsive parties on the ground would not be available for support/...
5
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2answers
556 views

Physical meaning of perigee advance

I'm starting to study orbital perturbations and I can't find any physical explanation about the perigee advance (apsidal precession) when considering Earth oblateness effects. Can someone give a ...
3
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1answer
1k views

Roughly, how fast do rockets travel?

I know that different rockets are built with different a range of different sizes or purposes, but there must be some kind of range of typical speeds for those things when leaving the Earth. So how ...
3
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1answer
6k views

Does escape velocity apply to rockets? [duplicate]

I know so far that escape velocity on the surface of Earth is 11.2 km/s Wikipedia says that escape velocity is the minimum speed needed for an object to escape from the gravitational influence of a ...
11
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2answers
381 views

Why is the surface of Mars oxidized?

Before 2.5 to 2Gya, Earth's surface was a chemically reducing environment (evidence includes reduced forms of iron, sulfur, and uranium in rocks before that time). It is believed to have become ...
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2answers
8k views

Is it true that NASA is hiring a new 'planetary protection officer'?

NASA is hiring a new 'planetary protection officer' to defend Earth from alien matter, and the pay is a six-figure salary: as much as $187,000 a year. When we are not sure whether aliens exist, why ...
3
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2answers
1k views

Launching a rocket from a weather balloon for a very small payload

I am new to the site and am unaware of the correct formation of my question. That being said, I wanted to know if this is plausable and what would be the correct way of tackling this idea. If I had a ...
8
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4answers
4k views

Is it possible to touch stars with our bare hands?

Well I'm new to Space SE and have gone through many questions but I couldn't help but notice that is it even remotely possible that one can touch the stars without burning him/her self ? Is there any ...
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1answer
145 views

What would happen to communication if we stayed in contact with a person going to mars?

If we talk to a person on mars it would take about 30 minutes before they would see the communication, but lets say we stayed in contact 24/7 by video calling starting from Earth, what would happen? ...
7
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0answers
224 views

Why doesn't jupiter look bigger than our moon? [closed]

If Jupiter is 365 million miles away from earth. Our moon is about 238,900 miles away from earth. that means Jupiter is 1527.8 times farther away from the earth than the moon. Jupiter is 5285.2 times ...