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48 votes
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Why is Jupiter called a "Gas Giant"?

Jupiter being a gas giant is not about its appearance, as another answer stated. It's only about the mass distribution of a planet. Jupiter's mass is 320 Earth masses, while we know from the Juno ...
AtmosphericPrisonEscape's user avatar
37 votes

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

Any hypothetical planet (or other object) even further out would be very dark, so few photos are taken for any reason other than to look inward. (And in any case, the cameras on the Voyagers are shut ...
GremlinWranger's user avatar
27 votes
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Do any planets other than Earth have artificial satellites?

Yes, certainly, around 6 of 8 planets in the Solar System, the oldest of which, The 2001 Mars Oddessey orbiter has been in orbit around another planet longer than any other satellite. A key thing to ...
Edlothiad's user avatar
  • 2,127
24 votes

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

There are five probes leaving the Solar System. Pioneer 10 and 11 are no longer functioning. Voyager 1 and 2 are functioning but their cameras have not been used since the early 1990s, and it is ...
Andrew is gone's user avatar
19 votes
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Is Mohs scale of mineral hardness applicable for rocks and minerals of terrestrial planets other than Earth?

Yes, because for the vast majority of minerals you can find in space, they are the same as those you can find (or synthesize) on Earth. A pyrite in space is a pyrite just like on Earth. A wollastonite ...
Anton Hengst's user avatar
  • 10.7k
18 votes

When a planet loses atmosphere, where does it go?

Escape from planetary atmospheres of the terrestrial planets in our solar system is dominated by ions in absolute numbers, as opposed to neutral particle species. Particles can be any type of molecule ...
AtmosphericPrisonEscape's user avatar
18 votes

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

Yes, but with a couple modifications. On some planets, notably Venus within our Solar Systen, different conditions from those on Earth, especially temperature, can affect mineral hardness. Pyrite is ...
Oscar Lanzi's user avatar
  • 8,495
17 votes
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Which of the outer planets could you see with the naked eye if you were in close proximity?

You can try for yourself how bright it is on Pluto. High noon on Pluto is as bright as a certain point during dusk/dawn on Earth. I tried this, at that point it's bright enough to make out details. My ...
Hobbes's user avatar
  • 127k
16 votes

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

Planet Nine semi-major axis is estimated to be 400 AU to 800 AU. New Horizons is now about 50 AU away from the Sun and travels about 3 AU per year. So in about 120 years New Horizons will be 400 AU ...
Uwe's user avatar
  • 48.9k
16 votes

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

It is actually pretty likely we have seen Planet 9, but just don't know that it is in fact moving. The problem is to know something is an object in the solar system, we have to see it move, and an ...
PearsonArtPhoto's user avatar
  • 121k
14 votes

Why is Jupiter called a "Gas Giant"?

One reason they are called gas giants is because they are mostly composed of elements that are gaseous at Earth like temperatures and pressures. Jupiter is primarily composed of hydrogen with a ...
M.A. Golding's user avatar
14 votes
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Why is TRAPPIST-1f considered habitable?

None of the TRAPPIST-1 planets are "considered habitable"; we don't know nearly enough about them to say that (any news article which referred to the planets themselves as "habitable" needs firm ...
Russell Borogove's user avatar
13 votes
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Which of the planets could we detect today from just the movements of the sun?

Getting hard numbers about how accurate measures we can get from current systems, adapted to the Sun instead of far away stars is difficult, bordering to impossible. But we can get data about the ...
SE - stop firing the good guys's user avatar
12 votes
Accepted

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

I would argue that it is disproven already. There have been studies done with Extrasolar planets, and it has been found to only apply in a very small number of instances. There might be some that ...
PearsonArtPhoto's user avatar
  • 121k
10 votes
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Elliptical orbits transformed to "equivalent" circular orbit

The period $T$ of some satellite in orbit is determined by its semi-major axis $a$, so for a given $a$ (and central body), the orbital period will always be the same: $$T = 2\pi \sqrt{\frac{a^{3}}{GM}...
Jack's user avatar
  • 9,976
9 votes
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Are there planets that are tide-locked to their sun?

Yes, any planet within a sufficient distance from the parent sun is assumed to be tidally locked. Proxima Centauri B, the nearest exo-planet to the Earth, is believed to be tidally locked. Pluto and ...
Chris B. Behrens's user avatar
9 votes

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

I'm going to make the assumption that you mean life other than humans. Humans can survive anywhere with enough technology, even frozen, lifeless rocks. We don't even need a planet, as our experience ...
GdD's user avatar
  • 20.2k
8 votes

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

Bright sun light of a clear sky is about 100,000 Lux, room light at night about 100 Lux, street light at night about 10 Lux. We are thus able to see with 1/10000 of the brigthness of summer day with ...
Uwe's user avatar
  • 48.9k
8 votes

Why is TRAPPIST-1f considered habitable?

The temperature estimate is based on no atmosphere. For instance, Earth, without our atmosphere, would have an average temperature of -20°C . The equator should be warmer, and any atmosphere will also ...
PearsonArtPhoto's user avatar
  • 121k
8 votes
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Explain this light and wavelength graph

While this animation is somewhat misleading as the wavelength line seems to be following the position of the exoplanet as it passes the star, I think this is an example of Exoplanet Spectroscopy. ...
Dragongeek's user avatar
  • 18.7k
7 votes
Accepted

Does Sunlight have a range?

Light is electromagnetic energy conveyed by photons. Photons travel in straight lines at approximately 300,000,000 m/s. They do not lose any energy as they travel, so can travel indefinitely, only ...
Anthony X's user avatar
  • 17.4k
7 votes

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

Mercury is tidally locked to our sun, although in a 3:2 resonance, not 1:1 as you're probably imagining. There is therefore one day on Mercury every 2 years (3:2 from an exterior frame of reference; ...
Walter's user avatar
  • 71
7 votes

When a planet loses atmosphere, where does it go?

Basically it is blown away by the solar wind, headed to interstellar space. A light particle in orbit around the Sun will tend to be pushed further out with time because of both solar wind and ...
PearsonArtPhoto's user avatar
  • 121k
7 votes
Accepted

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

Yes, it is possible that geothermal activity can achieve habitability. In 2018, a group of scientist discovered an extrasolar planet (Barnard’s Star b) orbiting Barnard’s star, an M-type (red dwarf) ...
Nilay Ghosh's user avatar
  • 1,015
6 votes

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

Bodes law is a little over stated. It's not a law per se but rather a rule of thumb or a rough guideline It also doesn't work on our solar system exactly. For it to apply perfectly for our system ...
Diesel's user avatar
  • 271
6 votes
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Exoplanet(s) that share orbit?

Two planets sharing their orbit is expected to be a rare configuration. Most configurations of 2 planets in 1 orbit are unstable. Only when one planet is in a Lagrange point of the other, are the ...
Hobbes's user avatar
  • 127k
6 votes
Accepted

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

What you're possibly asking about is the scale height of an atmosphere. To clarify, atmospheres don't simply abruptly stop existing at a certain height. They decrease in density and pressure ...
AtmosphericPrisonEscape's user avatar
6 votes
Accepted

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

In addition to solar radiation/wind, cosmic radiation. Regarding surface conditions (soil) you will need consider: Potential nutrients for plants as well as toxins for plants, humans and other ...
Fred's user avatar
  • 13.1k
6 votes

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

Yes, for the simple reason that it is a scale of hardness rather than a classification of minerals: the minerals serve only as exemplars of hardness at various places on the scale.
Mark Morgan Lloyd's user avatar
5 votes
Accepted

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

Galactic centre: -29.01° declination and 17.76 hours right ascension, Voyager 1 12.44° declination and 17.163 hours right ascension, missing by ~40° Voyager 2 −55.29° declination and 19.888 hours ...
SE - stop firing the good guys's user avatar

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