Celestial body that orbits following an elliptical path around a star or stellar remnant.

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15
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1answer
369 views

Relationship between Mars and Earth rotation

Is it by pure random chance that Mars and the Earth have nearly the same day duration (Mars day is barely 40 minutes longer, which is just 3% difference), or there is some causal relationship between ...
0
votes
1answer
21 views

Can large bodies spin both ways

Can a planet, stars, moons, solar systems or black holes rotate on 2 axis? and if so is it possible to have 3 or 4 axis? Two axes for rotational motion does not cover if planets can hove 2 axis in a ...
6
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2answers
4k views

What does the phrase “limb of the earth” or “atmospheric limb” mean?

What does the term limb of the earth (see this question, for example) or atmospheric limb mean? The phrase strikes me as very odd, since earth is nearly spherical. Do other planets with atmospheres ...
-1
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3answers
96 views

Gravity effects when deleting stars or planets

In one of the latest SCIFI movies, they collect a star absorving it entirely in a kind of planet size gun/machine. As mass cannot disappear, I assume it was just concentrated inside their machine (...
7
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2answers
2k views

What planets are visible to the naked eye from Mars?

Here on Earth we are blessed with being able to see some other planets, Mars & Venus etc, with the naked eye on a fairly regular basis thanks to the distance between the planets. What about from ...
5
votes
3answers
1k views

Could the sky on a planet theoretically be any color?

The sky on the Earth is blue. Could the color of the sky on a planet with an atmosphere be of any color theoretically? Which colors are the most likely? I think it would be really awesome to have ...
2
votes
1answer
174 views

Magnetic field line distribution

If I had a magnetic bar in space that was 2cm wide and 2cm high and was one Earth diameter long and had the same magnetic strength as the Earth, would the distribution of field lines be the same ...
-1
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1answer
25 views

Finding density ratios with missing information? [closed]

How would you go about solving this problem? You can't find the densities since the volumes are missing.
0
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0answers
35 views

Ultra-cold gas giant atmospheres

In the troposphere, which has the bulk of the atmospheric mass, it's colder at higher altitudes due to adiabatic lapse. Gas giants have several different chemicals that condense into cloud decks at ...
11
votes
1answer
569 views

What would the collision between a (large) solid planet and a gas giant be like?

Assuming a Jupiter-like planet and an Earth-like planet (Except, say... half the mass of Jupiter), what would happen when the two collide? For clarification: What would the actual collision be like? ...
1
vote
1answer
24 views

Would a celestial body in a horseshoe orbit be tidally locked to the planet?

A smaller celestial body like a moon or an asteroid can be in a horseshoe orbit around a planet. Since it might go inside the tidal lock radius (but does not stay inside it all the time), during the ...
2
votes
2answers
1k views

What would happen if a hydrogen bomb were to explode in Saturn's atmosphere?

Purely hypothetical since any kind of testing in atmosphere/space is banned by international legislation/agreement. The humans have already bombed Luna so ... what could be expected to happen on ...
4
votes
1answer
144 views

Protoplanetary disks, angular momentum and prograde orbits

So you've got a protoplanetary disk and you're going to gravitate yourself some planets together. The disk is made up of the usual planetary system stuff, dust and gas and whatnot, orbiting a common ...
-3
votes
1answer
49 views

How is the Earth moving in a elliptical orbit around the Sun? [duplicate]

If gravity is transmitted by a four-dimensional fabric of spacetime and the Sun creates a bend in it ,which causes planets to orbit it , shouldn't the planets move in a circular orbit around the Sun ...
3
votes
2answers
2k views

How does one measure Earth's speed of revolution around the sun?

I know that there are several formulae that one can plug numbers into to arrive an estimate of Earth's speed around the sun (Kepler's third law for instance), but I'm wondering how these things are ...
4
votes
0answers
41 views

Barycenter correction for inner planets in solar system?

I want to run simulations of the solar system, and I've read in some papers that to speed up the simulations it is useful to use the barycenter correction of the inner planets (from Mercury to Mars), ...
3
votes
2answers
505 views

How does rogue planet PSO J318.5-22 stay 800ºC?

According to this article, the rogue planet (meaning a planet which does not orbit a star) PSO J318.5-22 has a surface temperature of 800ºC and weather that features molten iron rain. Without a star ...
5
votes
2answers
221 views

Could planets survive their star becoming a black hole? [duplicate]

Would the supernova responsible for its formation destroy them. The question becomes one of how destructive the supernova event is to its own solar system - does it completely evaporate all planets up ...
0
votes
1answer
47 views

What is the difference between habitable and Goldilocks zone?

If I am right, Habitable Zone means that a planet is on such a distance from its Star which makes it good candidate for supporting some sort of life. But then what is Goldilocks zone and how is it ...
2
votes
3answers
4k views

Artificial planetary magnetic field

I wonder how difficult it is to create an artificial planetary magnetic field with generators? What power they would need? The question is inspired by thinking about possible colonization of Jupiter'...
7
votes
1answer
183 views

What coordinate system is used to describe planets positions in the universe?

How are planets positions described in the space and in respect to what? For example is Sun the origo and right now at this moment Earth has [coord_X, coord_Y, coord_Z]? or maybe [lng, lat]? Edit1:...
7
votes
0answers
49 views

Are there any models for distribution of asteroid sizes in a belt?

Question: Is there any function that can describe the distribution* of asteroid diameters expected within an*' asteroid belt? *: distribution as frequency of occurrence within the asteroid belt or ...
1
vote
1answer
60 views

Mathematically calculate if a Planet is in Retrograde

How do you mathematically calculate if a Planet is in Retrograde when you are given both the Earth and the Planet Keplerian Elements value and rate? Keplerian Elements are: a - Semi-Major Axis; e - ...
3
votes
1answer
36 views

Which force transfers angular momentum in tidal locking?

The moon is in tidal lock with the earth, but a long time ago it was not. As the moon became tidally locked with the earth, its angular momentum changed and the delta went into it's orbit and possibly ...
2
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1answer
84 views
1
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2answers
34 views

How to calculate the mass of the orbiting body given only its orbital information

A question asks the following: Using Newton’s Law of Gravity, show that the mass of a planet can be written: $$M = \frac{4\pi^2a^3}{ GP^3}$$ where $a$ is the semi-major axis and $P$ is the orbital ...
11
votes
6answers
3k views

Can low-gravity planets sustain a breathable atmosphere?

If astronauts could deliver a large quantity of breathable air to somewhere with lower gravity, such as Earth's moon, would the air form an atmosphere, or would it float away and disappear? Is there a ...
-3
votes
1answer
66 views

If we live on the surface of Earth then why Earth images shows maps around it? [closed]

If you visits google map and go to earth we see the image as attached below. My question is if the earth is round like sphere ball and if we live on the surface of this ball (point me if i am ...
2
votes
2answers
295 views

Planetary alignment of the gas giants?

There is this nice and new applet of the orbits of the planets around the sun: Solar System Orrery You can click and drag any planet and watch their relative orbits evolve in time. I was curious ...
1
vote
1answer
46 views

Small enough planet to notice rounding

This is my first question on Physics StackExchange, so bear with me. I am wondering. How dense would a planet need to be for a human to notice the fact that the planet is not flat, but round, by ...
0
votes
1answer
60 views

planetary scale motor

A spinning mass of a motor has a gyroscopic effect when moved. As the mas and size of the motor approaches the size of the planet it sits on, what kind of effects would this cause to the planet?
4
votes
2answers
1k views

Does surface tension play a role in planet's shape?

I'm thinking that when the planets and stars were forming along with gravity surface tension also could have played a role in making them spherical. Am I correct?
7
votes
1answer
144 views

What colour would the sky of a high-oxygen, high-argon, high-water vapour atmosphere be?

Although this is a hypothetical, I think it is nevertheless a legitimate physics problem. I would very much appreciate any answers you can give. What colour would the sky be, both at daytime and at ...
0
votes
1answer
51 views

Spacetime Mercury vs Earth

What is the time dilatation of the planet Mercury compared to Earth? Can a person survive on the dark side of Mercury in the In the L2 position to Mercury and the Sun?
2
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1answer
63 views

Atmospheric pressure of Venus?

I have seen the calculations on the atmospheric pressure of Venus - 90 times that of earth. With gravity very similar to earth, how does Venus do that. The calculations I have seen assume constant ...
8
votes
3answers
3k views

How do you explain Kepler's third law in general terms without complex math?

I understand the first law-elliptical orbits, and the second-equal area in same time, but I need help with the third one. Note that I am not in an AP course or taking calculus at the moment so simple ...
1
vote
2answers
53 views

What is the reason for Earth's rotation and revolution?

Is it because of the gravitational effect of the other planets and the sun then why do the other planets rotate and revolve too? And well does the Sun rotate and revolve too?
-1
votes
1answer
60 views

Why does gravity make objects spherical? [duplicate]

Why is it that gravity tends to make large objects spherical? I'm looking for reasons that are based on the laws of physics.
8
votes
3answers
490 views

Can a planet form before the parent star ignites?

I'm unable to find an answer to my questions via my searches. This questions pertains to the timeline of a star system creation. My question: During the creation of a star system, can satellite ...
1
vote
3answers
150 views

If planet like Jupiter is massive enough to hold hydrogen with its gravity is it bound to become a star?

I have been reading about Jupiter as of late and reason I am asking is if Jupiter has strong enough gravity to pull hydrogen to itself then it should be only matter of time when it will acquire enough ...
1
vote
2answers
65 views

Planets potential [duplicate]

I'm a physic student of Italy. I'm moving my first steps in this beautiful world, and as every new entry, my simple and stupid questions are sometimes not so simply resolved. I'm trying to know the ...
0
votes
2answers
62 views

The shortest path among two points inside Earth [closed]

I have this idea and I don't know how to process, explain or question it. I hope you can understand these images and help me formulating a good question. This is like a gravitational train but it ...
12
votes
1answer
297 views

Local temperature equation for a planet

After seeing in science fiction too many planets with two suns that look too much like a geocentric system, I'm trying for my own amusement to understand if it's really possible to have a planet with ...
0
votes
0answers
21 views

Gravity changes at the equator due to Earth's spin [duplicate]

If an object weights 100 kilos at the equator how much would it weight if the earth spun twice as fast?
2
votes
1answer
28 views

Can a tidally locked planet have a horizontal rotational axis?

Is it hypothetically possible for a planet to be both tidally locked, and still have a rotation "horizontally"? Where the substellar point would in effect be like the point of a top, spinning and yet ...
0
votes
1answer
55 views

Why do planetary all rings seem to be on the equatorial plane?

Why do planetary all rings seem to be on the equatorial plane? When I first saw a picture of Uranus and its rings, I was surprised by their inclination, 90 degrees from the axis of rotation. This ...
11
votes
3answers
3k views

Is it possible to see satellites with the naked eye?

Every now and then I notice some very bright "stars" in the sky. They tend to be very few (one or two, usually), and are quite much brighter than any other star out there. Often they're perfectly ...
1
vote
1answer
40 views

How is the stellar flux for exoplanets calculated?

I have noticed that in many Wikipedia articles, the stellar flux received by each planet is stated. I tried to calculate this stellar flux from the given data, but the results didn't seem to be ...
0
votes
3answers
110 views

Could the recent evidence of a gravitational force orbiting the solar system indicate not the existence of a ninth planet, but rather a black hole?

In case you haven't heard already, researches at the California Institute of Technology discovered mathematical evidence of large object orbiting the sun at a distance about 20 times further than that ...