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Questions tagged [planet]

Questions regarding astronomical bodies orbiting stars which are of proper size to be called planets.

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1 answer
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Would the Earth still precess if it were an ideal sphere?

I am trying (unsuccessfully) to acquire an intuitive understanding of planetary precession. Is Earth’s precession Torque-free Precession due to its asymmetry as per https://en.wikipedia.org/wiki/...
Woody's user avatar
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7 votes
1 answer
301 views

What would Venus look like without acid clouds?

Despite its unpleasant surface conditions, Venus is undoubtedly one of the most beautiful worlds in the solar system when viewed from space. It’s huge clouds of sulphuric acid make the planet ...
user50946's user avatar
2 votes
2 answers
194 views

best way to generate electricity on any planet's dark side

What options are available for generating electricity in a space colony if it is at the planet's darkest point all year around without help from nearby outposts?
Osm's user avatar
  • 121
0 votes
0 answers
40 views

Most accurate method to find exoplanets?

NASA has found thousands of exoplanets in space using their powerful telescopes. How exactly does NASA do so and what is the best method? I'm assuming that NASA uses some sort of sensor to detect ...
DialFrost's user avatar
  • 1,673
2 votes
1 answer
141 views

Density vs ocean planet?

According to Nasa.gov: Details: Ocean planets are long imagined but difficult to confirm, and TOI-1452 b is no different. About 70% larger than Earth, and roughly five times as massive, its density ...
DialFrost's user avatar
  • 1,673
9 votes
4 answers
1k views

Is it possible for a planet to be habitable by just geothermal activity

Is it possible for a planet (with an atmosphere and breathable air obviously) to be super far away from its star but still have a habitable surface temperature just from geothermal activity alone, if ...
NuclearTaco's user avatar
6 votes
2 answers
256 views

What is the largest possible rocky body? [closed]

Suppose you start with a rocky sphere about 12,742 kilometers in diameter and continuously add more rocky material such that you don't smash this sphere to bits. What is the upper limit for this? ...
Frotz's user avatar
  • 161
0 votes
1 answer
91 views

Wondering about materials [closed]

I am currently designing a Revit project on the planet Mars I was wondering what a wall on a base like structure need to consist of to protect its from the planet atmosphere. any thoughts ? regards, ...
matt's user avatar
  • 11
1 vote
2 answers
446 views

When and where on Planet Mars are the Sun's rays the most blueshifted?

Let's say for a moment that the spin of a planet causes the Sun's rays to be blue-shifted in the morning. As far as I know, redshift occurs in steps of like 2.6 km/s or something like that. We can't ...
Tomer Blobaum's user avatar
0 votes
1 answer
160 views

Intercommmunication between crewed space missions in all planets of solar system [closed]

As we know Human Communication taking place between Man in space, Man on Moon, Man on Mars (Future exploration) with Human beings on Earth planet where we are living with the help of control stations ...
Prashant Akerkar's user avatar
18 votes
5 answers
4k 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 ...
Nilay Ghosh's user avatar
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0 votes
1 answer
594 views

Which are the correct input parameters for NASA Horizons query to get the right Alt/Az data needed to plot analemmas for various planets?

I tried to replicate these analemmas, taken from a discussion of the equation of time in the following post: http://pbarbier.com/eqtime/eqtime.html: I used "Quantity n.4" for Nasa Horizons ...
jumpjack's user avatar
  • 3,033
30 votes
4 answers
5k views

Could one of the interstellar probes discover Planet IX by accident?

Could one or some of the spacecraft sent beyond the Kuiper belt discover (or even disprove) the hypothetical Planet IX? That doesn't necessarily mean coming so close you'd recognize the planet in ...
Giovanni's user avatar
  • 515
0 votes
1 answer
865 views

What would happen if Jupiter became solid like Earth and condensed to the size of Earth? [closed]

I just want to know, hypothetically, what if Jupiter was solid and condensed to the size of Earth. What would it look like? Would it's characteristics (gravity, orbit, rotation, etc) stay the same, or ...
Brett O'Donnell's user avatar
1 vote
1 answer
83 views

Is the sunlight reflected off of either the atmosphere or surface of a planet polarized?

Is the reflecting off of the surface of the terrestrial planets (those with or without an atmosphere), or the gas- or ice-giants, polarized, or unpolarized like the sunlight before it is reflected?
Bob516's user avatar
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7 votes
2 answers
255 views

Any additional information required for colonising these rocky solar system bodies?

I am doing some research into the nearby rocky bodies Mars, Venus and the Moon with reference to human colonisation. Are there any specific pieces of information that would be useful to know about ...
Pedro Hablespanyos's user avatar
0 votes
0 answers
35 views

How can the download speed increase from space probes? [duplicate]

It always seems to be a genuine question that is How can we download data from far away probes in instant. When New Horizons reached Ultima Thule, it took us quite a few months to have a great picture ...
Pranay's user avatar
  • 482
11 votes
2 answers
2k views

When a planet loses atmosphere, where does it go?

Hydrogen and helium are quite rare in Earth's atmosphere, despite being the most abundant elements in the universe. Planets such as Mars have even lost almost all their atmosphere. The usual ...
Michael's user avatar
  • 471
5 votes
1 answer
342 views

Explain this light and wavelength graph

Would someone please explain this graph. I am not an expert and with my limited understanding of physics, I am unable to correlate this graph between the light received with its wavelength. I don't ...
roottraveller's user avatar
2 votes
1 answer
171 views

Is it possible to have a planet made entirely out of water? [closed]

Let's say we had a mechanism of adding unlimited amounts of water at a certain point in space. How much water could we add until the water molecules would turn into something else due to gravity? What ...
Stefan Mihai Stanescu's user avatar
1 vote
0 answers
90 views

Which object has been on other planet(s) or other natural bodies the most times? What if orbits count?

Following answer(s) to Which object has been to space the most times? answer, and related to Objects that have been on the Moon multiple times one. Question: Are there any object(s) that travelled to ...
JuanCa's user avatar
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2 votes
1 answer
86 views

What is the state of the art of exosolar planet imaging in 2019?

I have seen this question from 2013 asking if it's possible to take pictures of extrasolar planets. But I am wondering if anything has changed since then. Have we taken higher quality images of other ...
Outsider's user avatar
  • 578
5 votes
1 answer
353 views

Which planet gets the most money? Which gets the least?

I'm curious if anyone has ever tallied the expenditures of all of the world's space programs, and then tried to divide it by which planet was targeted. It's possible this has already been done. If ...
uhoh's user avatar
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4 votes
1 answer
1k views

Elliptical orbits transformed to "equivalent" circular orbit

I'm trying to transform Mars' elliptical orbit into its circular "equivalent". I understand that if the semi-major axis is used as the radius, and the mean angular rate and period are kept the same, ...
Harvey Rael's user avatar
2 votes
0 answers
50 views

Saturn's tropical year [closed]

What is the value of Saturn's "tropical year" (as opposed to its "sidereal year"). I am seeing it listed as 10 days shorter (10,747 days) than the sidereal year (10,759 days). How could this be if ...
PaulS's user avatar
  • 121
1 vote
1 answer
287 views

Calculate the state vector of planets and moons

What is the efficient way to calculate the state vector of planets and moons? The coordinate system for planets would be with center in Solar System Baricenter, for Moon- with center in Earth and in ...
Tarlan Mammadzada's user avatar
6 votes
2 answers
470 views

Are there planets that are tide-locked to their sun?

An interesting question was raised about satellites being tide-locked (Does a satellite naturally turn in phase with its orbit, always facing Earth?). It was a educational read for me, and in one ...
miltonb's user avatar
  • 285
13 votes
2 answers
15k views

Do any planets other than Earth have artificial satellites?

Space probes have been sent to fly by or temporarily orbit other planets. Have any artificial satellites been sent to permanently orbit another planet and record data? "Permanent" as in purpose of ...
Dan Sorensen's user avatar
  • 3,561
4 votes
1 answer
258 views

Is there a planet walk with the positions of Voyager 1 and 2?

There are a lot of walks like the Sagan Planet Walk (see the list on Wikipedia). But are there any of these walks that include the position of the Voyager space probes? Some days ago I was ...
Uwe's user avatar
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1 vote
1 answer
452 views

Could a Uranus-style planet tidally lock?

I was reading this world building post and it got me thinking - every body eventually tidally locks with the body it rotates with. Let's say for a moment a planet near the sun had a Uranus style axis ...
corsiKa's user avatar
  • 321
34 votes
4 answers
11k views

Why is Jupiter called a "Gas Giant"?

Jupiter's enormous gravity would turn its atmosphere first into a liquid from a certain depth, and then into a solid further towards its centre. So Jupiter has a solid core, above which is a liquid ...
boardrider's user avatar
1 vote
1 answer
335 views

Does Sunlight have a range? [closed]

If you switch on a lightbulb in a room its light has a visible range. So how about Sunlight? Does it light more on Mercury and less on Pluto? And what about planets that are not in the Solar System?
Prolog's user avatar
  • 113
0 votes
3 answers
173 views

How does "planetary protection" apply to Europa since Europa is not a planet?

NASA has this "planetary protection" scheme. But it seems to apply to non-planets, like Enceladus and Europa. Thus Galileo and Cassini probes are crashed into their gas giants. How does this add up? ...
LocalFluff's user avatar
5 votes
3 answers
1k views

When will we be able to conclusively confirm or disprove Bode's law?

I am reading Heinlein's Time for the Stars(1956) and some of the characters are very excited about confirming Bode's law. The formula suggests that, extending outward, each planet would be ...
James Jenkins's user avatar
6 votes
2 answers
2k views

Why is TRAPPIST-1f considered habitable?

The TRAPPIST-1f is in the TRAPPIST-1 system discovered recently with seven planets. Three of them are said to be in the habitable zone. But the data says that the average temperature on the TRAPPIST-...
KKZiomek's user avatar
  • 325
2 votes
1 answer
208 views

Exoplanet(s) that share orbit?

Has Kepler (or any other survey) found an exoplanet with a similar orbit as another exoplanet around the same star? The current IAU definition of a planet requires that "a planet has cleared its ...
MarsOneOrBust's user avatar
3 votes
1 answer
3k views

Is there a calculation for determining the thickness of a planet's atmosphere?

I'm wondering if there a way to determine how thick (from the surface to the edge of space(karman line)) a planet's atmosphere would be. Assume an earth body like Earth or Mars (not a gas giant). I ...
DMfiend's user avatar
  • 133
2 votes
0 answers
82 views

Rocky Planet around Proxima Centauri - how can we learn more about it?

Besides an epic millennium-long interstellar voyage by a probe, what can we possibly do to learn more about this rocky planet discovered around Proxima Centauri? I understand that we have some ...
orulz's user avatar
  • 433
12 votes
2 answers
966 views

Which of the outer planets could you see with the naked eye if you were in close proximity?

My question is which of the outer planets you could see with the naked eye if you were in close proximity to them. It's pretty obvious the human eye can see the inner planets through to Mars, but I ...
GdD's user avatar
  • 20.3k
7 votes
0 answers
193 views

What do the enclosed numbers represent? [closed]

A friend asked me what the numbers in the following image represent: ...
Keira Dueck's user avatar
6 votes
3 answers
8k views

Which planets and moons can you walk on?

Which planets and moons have a surface where you could survive with a conventional or near-future spacesuit? Assume oxygen, water, and food supplies are accounted for, but roughly current limitations ...
Allahjane's user avatar
  • 323
7 votes
2 answers
2k views

Why would Hollywood's Planet X (at earth's L3) be unstable?

This NASA website states "NASA is unlikely to find any use for the L3 point since it remains hidden behind the Sun at all times. The idea of a hidden "Planet-X" at the L3 point has been a popular ...
uhoh's user avatar
  • 149k
5 votes
3 answers
349 views

Has any other term been used for a solar day on a solar system body besides "sol" on Mars?

My interest was piqued by this question and answer. For several reasons NASA needed to refer frequently and extensively to a Martian solar day, and "sol" became the nom du jour. There have been ...
uhoh's user avatar
  • 149k
11 votes
1 answer
423 views

Are any spacecraft heading remotely where Planet 9 is expected to be?

Planet 9, the hypothetical planet predicted Batygin and Brown, is expected to have an apoasis near the galactic center. Is there a spacecraft that is heading in that direction? Specifically, they ...
PearsonArtPhoto's user avatar
  • 121k
12 votes
4 answers
4k views

What is the exact format of the JPL ephemeris files?

I'm attempting to do some basic planet position calculations using the JPL ephemeris data. The first step is to properly parse the files. Here's my understanding so far: The header file gives a ...
Lukas Bystricky's user avatar
2 votes
1 answer
99 views

Could two planet-like objects be created-as or form a binary pair that orbits something else?

Could two identical or slightly different planets (or planet-like objects if you want to be pedantic) form a binary pair that then orbit some other larger gravitic object (like a star)? I was ...
killermist's user avatar
16 votes
3 answers
3k views

Could twin planets exist and share the same orbit?

Could there be a stable orbit shared by two planets with the same mass and density? Regardless of whether the formation of such system is possible or not. For example, if Earth and Venus could have ...
rraallvv's user avatar
  • 361
30 votes
2 answers
765 views

Which of the planets could we detect today from just the movements of the sun?

Assume that despite our current level of space exploration and technology, we have somehow missed the existence of the other planets in our solar system. We have developed various methods of ...
Max Q Lagrange's user avatar
11 votes
2 answers
4k views

Is there a term to refer to a planet and its accompanying moons as a whole collection?

I am trying to find out of there is a term that can be used when referring to both a planet and any accompanying moons (if present) as a whole collection. For example if you were to refer to Mars and ...
jwvanderbeck's user avatar
9 votes
2 answers
1k views

From which celestial bodies do we have samples?

Excluding our own, which bodies have we directly (or indirectly) gathered samples from? I'm aware of these: Moon: moon rocks from Apollo Mars: Martian meteorites found on Earth What else?
Gstestso's user avatar
  • 817