Questions tagged [earth]

Questions of the science and space exploration related to Earth.

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0answers
30 views

Biggest orbital inclination change done in Earth's orbit

Generally orbital inclination change is said to be (fuel) expensive. What is the biggest orbital inclination change (in degrees) done in Earth's orbit for an orbiting object? Can this be broken down ...
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1answer
61 views

How much of the total angular momentum of the Earth-Moon system is due to the Moon?

I've read that the total angular momentum of the Earth-Moon system is 3.41x10^41 g.cm^2/s (1). How much of that is due to the Moon? In other words, if the Moon ceased to exist and the Earth ...
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102 views

Why are minimum three artificial satellites required for radio-communication all around the Earth?

Artificial satellites orbiting the Earth have important applications for radio-communication around it. To avoid the blockage of radio-communication around the Earth, multiple satellites can be ...
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30 views

If I know the masses, positions, and velocities of two objects, how do I calculate their trajectories under gravity?

I was thinking about the effect of a near-miss with an asteroid upon the orbit of the earth around the Sun. My goal is to figure out a formula I could use for a visualization I'd like to build to get ...
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1answer
126 views

Do astronauts on ISS notice Earth's seasons?

Has anyone stationed on the ISS for some months reported noticing the changing seasons on Earth in any way like people on the surface do, subconsciously without needing to look up numbers for anything?...
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220 views

How to plot this orbit?

I have these data for some orbits, without any explanation about meaning of each datum: ...
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48 views

How to convert body coordinate from Sun reference frame to Earth reference frame?

I have the coordinates of a celestial body w.r.t. Sun , expressed as (x,y,z), at a given time. I need to move this coordinates into a reference frame centered on Earth center, but after reading dozens ...
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3answers
6k views

Does it make any scientific sense that a comet coming to crush Earth would appear “sideways” from a telescope and on the sky (from Earth)? [closed]

In multiple different movies and fiction, there's the threat of a burning space comet heading for Earth, threatening to kill everyone and destroy the planet. One example is the animated Comet in ...
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5answers
3k views

Is Mohs scale of mineral hardness applicable for rocks and minerals of terrestrial planets other than Earth?

The Mohs scale of mineral hardness is a qualitative ordinal scale characterizing scratch resistance of various minerals through the ability of harder material to scratch softer material. Now there is ...
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1answer
38 views

Should coordinate transformations from J2000 to ITRF93 in quaternions be cyclic?

I used SPICE's pxform at an interval of epochs to determine the transformation from J2000 (inertial) to ITRF93 (Earth body-fixed) frame. Then, I converted these rotation matrices to quaternions with ...
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50 views

J2000 to current ECI transformation matrix

I want to find the transformation matrix that converts an ECI frame at some time 't' (lets say t = 1st January 2020) to J2000 ECI frame (that is ECI frame at noon of 1st January 2000). From what I ...
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Earth's Axial Precession and Frame Change [duplicate]

Is Earth's Axial Precession and change in Axial tilt values significant enough to be considered while writing Rotation matrix that converts Body frame into ECEF frame and also while propagating Orbit ...
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magnitude of magnetic anomalies (Earth and Mars)

I've been looking for the magnitude of highest and lowest magnetic anomalies on Earth and Mars (mapped by spacecraft in low orbit), by searching online I couldn't really find a numerical value. From ...
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2answers
258 views

Why do many Mars missions launch now, if the Hohmann transfer orbit is the most propellant-saving one?

The Hohmann transfer orbit is the most propellant-saving transfer orbit to Mars. When using this kind of transfer, the rover/rocket/etc. starts from Earth when Earth and Mars are in conjunction. But ...
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1answer
91 views

Would Earth without water look like Mars? [closed]

I was watching this slideshow of 4K images of the surface of Mars, and I noticed that the surface looked mostly smooth, with the most rugged features being crater impacts (sort of resembling an Earth ...
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150 views

Calculate Satellite ground track

I'm trying to find equations to calculate satellite position based on orbit parameters and given time. What I currently have is a mess that is basically giving me bunch of garbage. What is latitude ...
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46 views

Why spacecraft 's trajectory is shown undulating curve on 2D image of earth? [duplicate]

As i am watching live-stream of Demo-2 mission,the trajectory of a capsule is shown curved(like sin wave). In other words, why their trajectory isn't along longitude so that in 2D, the path followed ...
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1answer
137 views

Earth Live Video Feed in HD?

Is there any space agency that provides a live video of Earth, in HD? Preferably without anything man-made in the way (e.g some ISS robotic arm)? I want to create a live HD wallpaper of Earth, so I'm ...
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2answers
150 views

Is it easier to take off from the moon or earth? [closed]

how much mass does the moon have? how much mass does the earth have? how much force needed to leave earth how much force needed to leave the moon
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3answers
4k views

If the Earth spun clockwise, how would that affect Space Exploration?

If viewed from the North Pole, the Earth spins counter-clockwise. Because of this, many satellites also orbit in the same direction as you can take advantage of the Earth's rotation and essentially ...
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Can any aspect of the brightness of Martian twilight be determined by Curiosity's photo of Earth?

Curiosity took this image of Earth on Jan. 31, 2014, 80 minutes after sunset. Stellarium has the Earth >15° above the horizon 80 minutes after sunset on that day. With Stellarium indicating the ...
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1answer
80 views

What was the effective magnification of the Mars Reconnaissance Orbiter's HiRISE camera to acquire the detailed image of Earth?

On October 3, 2007 NASA's Mars Reconnaissance Orbiter HiRISE camera acquired this image of the earth and the moon from Mars The oceans and clouds can be easily distinguished and "the west coast ...
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Could the Apollo astronauts distinguish Earth's continents and oceans from the moon?

This article "Earthshine Reflects Earth's Oceans And Continents From The Dark Side Of The Moon" indicates that the difference in reflection of light from the Earth’s land masses and oceans can be seen ...
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What is the acceleration necessary for a Brachistochrone transfer from Earth to Mars?

With these orbital configurations, source-Bing leaving Earth on Aug 16, 2106 and arriving on Mars October 10,2106, what is the lowest continuously-applied acceleration that can make what is ...
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Earth Moon Pork chop plot

Does pork-chop plots exist for Earth-Moon System? I could only find pork-chop plots for Earth-planet systems.Could someone please shed some light on this topic?
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1answer
533 views

How to determine the distance between where Earth and Mars are two specific dates?

How would I find the solar-system-relative distance between where Earth would be on 2106/8/16 and where Mars would be on 2106/10/16, or any combination of dates. Image source-Bing Is there software ...
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67 views

Could Breakthrough Starshot be used to deflect asteroids and comets?

Would Breakthrough Starshot be able to deflect an asteroid or comet? I have seen thoughts about using the lasers that would launch Breakthrough Starshot to deflect asteroids or comets: https://www....
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2answers
249 views

What does Earth's J₂₂ moment look like?

Wikipedia's Geopotential model give's the form of the potential component linked to $J_2$ as $$u = J_2\frac{P^0_2(\sin \theta)}{r^3} = J_2\frac{1}{r^3}\frac{1}{2} \left(3 \sin^2\theta-1 \right) = ...
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How much does the earth's axis change its tilt every year? [closed]

In recent years it seems that the winter sun rises and sets even further south as parts of my house are illuminated with sunlight that I don't recall 4 or 5 years ago.
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5answers
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Is a midspace space station between Earth and Mars practical?

A recent answer included the following: For example if you were to start a colony on mars, in this order for supplies and other necessities to be delivered there would need to be a network of space ...
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1answer
115 views

Definition of a trans-Earth injection

Should every "propulsion maneuver used to set a spacecraft on a trajectory which will intersect the Earth's Sphere of influence" be called a trans-Earth injection? Regardless where the spacecraft ...
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4answers
5k views

What is the largest piece of space debris volumetrically?

What is the largest piece of space debris currently in Earth orbit by volume? Space debris is not limited to defunct satellites, but also includes things like spent upper stages. Bonus points for ...
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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 ...
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4answers
168 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
283 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 ...
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1answer
128 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 ...
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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 ...
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0answers
117 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 ...
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3answers
286 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 ...
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1answer
1k 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?
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1answer
181 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
86 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?
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101 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?
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1answer
759 views

Are we changing Earth's rotation?

Can rockets launching change Earth's rotation, and can going into orbit do the same?
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1answer
332 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 ...
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3answers
4k 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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9answers
14k 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 ...
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How far from Earth were the Apollo astronauts when they left the Earth's magnetosphere?

I am assuming the Apollo missions recorded radiation levels as they travelled to the Moon. Have those records ever been released, as a way of determining when the Apollo astronauts left the ...
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1answer
415 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'...
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1answer
120 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 ...