New answers tagged planets
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Plausible orbit to have a visible object slowly circle over the night sky
A binary star system around the planet's north pole
There's a serious issue with the question: You want the observer to use solar clock to determine "every night", but the star-based time ...
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If Io were the size of Earth, what would its atmosphere consist of?
I’d say the most important factor in determining the answer to this question is the geological composition of the planet. If its mantle is mostly made up of the same elements as Io’s, then it’s highly ...
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What size should my inside-out planets be so that people on the surface can see the curvature?
Technically ~6,000km across, but efficially, much bigger is fine
On a cloudless summer solstice day at noon, about 75% of the solar energy reaches the earth's surface at an intensity of ~100,000lux. ...
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If Io were the size of Earth, what would its atmosphere consist of?
Size alone is not sufficient to determine the atmospheric composition of a planet: size, and its related gravity well and escape velocity, determines only which gases the planet can retain on long ...
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Coral Islands and Atolls on a Drip-and-Plume world
We've seen on Mars that plumes tend to create nothing but massive mountains. Olympus Mons, the largest volcano in the solar system, was created because of a plume and its 3x the size of Mount Everest. ...
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What size should my inside-out planets be so that people on the surface can see the curvature?
The normal answer
Consider that we can see the surface of the illuminated Moon pretty clearly (citation needed). That distance is on average 384,00-385,000 kilometers depending on who you ask. If we ...
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Plausible orbit to have a visible object slowly circle over the night sky
This depiction of 20 stable 3 body problem solutions may provide an orbital set that suits.
Viewing highly recommended to all.
There are others. If one body other than your target world was luminous (...
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Plausible orbit to have a visible object slowly circle over the night sky
There are one relatively straight-forward answer and one where it would not be the night sky but the Sun itself
A (distant) giant planet with 200 years orbit
Any planet around the central star with a ...
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Could you please check my calculation for a habitable binary planet system?
According to this handy calculator the Goldilocks Zone of this system is from 0.7 to 1.0 AU, your worlds orbit right at the inner edge of this, they're going to be fairly warm with an Earthlike ...
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Plausible orbit to have a visible object slowly circle over the night sky
Sirius, as seen from either WISE 0855-0714 or Procyon, would probably fit the bill. Sirius is the single brightest star in Earth's sky, Procyon and WISE 0855-0714 are only a little over half the ...
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Coral Islands and Atolls on a Drip-and-Plume world
Rings atolls exist because the volcanic mountains they form around have sunk into the crust and dropped below the water line. Drip and plume volcanism should generally result in longer dwell time for ...
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Plausible orbit to have a visible object slowly circle over the night sky
You can use Lagrange Points and a comet.
Now, L2, which is the only point on the night side is unstable. This means that a comet caught there will eventually escape. L4 and L5 are stable, however, ...
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Plausible orbit to have a visible object slowly circle over the night sky
The world is orbiting one of a binary pair of stars, with a 200 year period. There is a third star toward the axis of the binary (toward the north or south poles of the binary system), either a very ...
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Accepted
Coral Islands and Atolls on a Drip-and-Plume world
It really depends on how densely distributed are these drip and plume spots, and how long they live before fading out.
With dense and short lived spots, you will have a lot of atolls going through the ...
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Coral Islands and Atolls on a Drip-and-Plume world
They should be much the same. Polynesia & Micronesia are mostly made from volcanic activity. Coral will form anywhere that the conditions are right and the rest follows.
The larger Islands like ...
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Weather in The Cluster World
In particular will water vapour be able to circulate up out of the high pressure core zone into the habitable pressure zone?
Yes
That is a qualified yes, as assumptions must be made, but lets compare ...
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Accepted
Creating a prison on the high-pressure ice of a deep oceanic planet
Pressure equilibrium vs material strength (frame challenge)
You do not need a material that is able to withstand the full pressure of kilometers worth of water above an underwater base.
All you need ...
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What unique phenomena would be observed in a system around a hypervelocity star?
The Milky Way and Andromeda galaxies are already on collision course at a speed of a similar magnitude to hyper velocity stars. So the hyper velocity star would arrive at Andromeda a lot sooner than ...
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What unique phenomena would be observed in a system around a hypervelocity star?
What a wonderful and weird question. The first thing to consider is how fast the earth is already moving. We calculate that the solar system is rotating around the galactic core at 700,000 km/h. ...
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What unique phenomena would be observed in a system around a hypervelocity star?
Hypervelocity stars are created through close gravitational encounters with other bodies, which are likely to strip away planets, especially those particularly far from the star. You have declared ...
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Is it possible to have a planet that's gaslike in some areas and rocky in others?
Hmm, how oblate is this spheroid?
If you, somehow, spin the earth 17 times as fast as it is now, so a day only lasts 84 minutes, you would feel a net 0 g at the equator (Whee!), while still feeling 1 ...
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Is it possible to have a planet that's gaslike in some areas and rocky in others?
Larry Niven's Known Space setting has two planets with something like what you're after.
One is called Plateau or Mount Lookitthat; it's a Venus-like atmosphere with a single flat-topped mountain ...
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Is it possible to have a planet that's gaslike in some areas and rocky in others?
I think it's possible if you consider a double planet system in very close proximity. Think Earth+moon, but both very similar size and both very very close (one or two diameters top). They would then ...
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Is it possible to have a planet that's gaslike in some areas and rocky in others?
No
The primary issue is that the planetoid is an entity which surface is shaped according to its own gravity, and a planet is more so, thus you can't really get "more gravity at the equator" ...
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Crustal composition of an ammonia planet
Well first some key points.
First, your pressure would not be 2.5 atm, it would be higher. Your world, assuming a distribution equal to that of the Earth, should have a gravity of approximately 3.3 g ...
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Is it possible to have a planet that's gaslike in some areas and rocky in others?
No, not really. Gravity gradient makes so that matters is arranged according to density, forcing the densest material to sink below the less dense.
Therefore having hydrogen below rock would not be ...
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Could a mini-Neptune host life at the surface with gas giant-style storms up above?
You haven't specified if you want a realistic or more fantastical answer. My answer is in regards to a Mini-Neptune, not a Super Earth, so keep that in mind.
The realistic answer is you wouldn't have ...
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Could a mini-Neptune host life at the surface with gas giant-style storms up above?
MiniNeptune - No
The primary reason of inability for gas giants to have life on their surface is sheer pressure. At mere 12 kilometers down here on Earth the pressure (granted it's rock, not gas) is ...
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Could a mini-Neptune host life at the surface with gas giant-style storms up above?
You can only have a hydrogen-helium layer with gas giant storms above a oxygenated atmosphere if vertical atmospheric mixing is effective zero. This means you have to have an atmosphere deep enough ...
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Will fire still burn well in my atmosphere?: concentration vs partial pressure
Here is a frame challenge.
You are worried whether combustion can happen in your atmosphere. What is the most important form of combustion for humans? Oxidation or combustion of various substances in ...
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Will fire still burn well in my atmosphere?: concentration vs partial pressure
Fire yes, wood no. There are compounds that when combined will burn, period, because one of them is a strong oxidiser and/or produces molecular O2, or even Ozone, as part of the reaction. However wood ...
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Accepted
Will fire still burn well in my atmosphere?: concentration vs partial pressure
It depends entirely on what you are burning
Hypoxic fire suppression systems exist where the oxygen percentage is lowered to 15%.
Hypoxic fire suppression wikipedia
In a normobaric hypoxic ...
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Will fire still burn well in my atmosphere?: concentration vs partial pressure
I’m a relativist/particle physicist, not a chemist, but I have seen diamonds combust at cryogenic temperatures when exposed to nearly-pure oxygen. As it turns out the carbon-oxygen-to-$\mathrm{CO}_2$ ...
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Accepted
How long would it take for an Earth-like planet to become uninhabitable if another sun suddenly appeared?
Not Long
It currently takes ~7 minutes for infrared radiation - the primary heat agent from the sun - to reach us. If you added a second sun, within 7 minutes the planet would be bathed in twice as ...
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Habitable world with abnormally low Argon
Biological activity
Some of your life forms produce cluster argon cations with several argon atoms held together because they have a collective positive charge. This only works because they are ...
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Will The Cluster World hold onto an atmosphere for a useful length of time without further intervention?
The hard part is keeping the atmosphere roughly uniform. If you evenly atomize the rock, so that the local gravity of each lump is minimal and the lumps are evenly spaced, then the atmosphere falls ...
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Accepted
Behaviour of volcanic eruptions and lava under a high-pressure supercritical water atmosphere
So at the highest temperature reached, 1500°C, and similarly high pressures, the magma and water are going to intermix as a semi-liquid (saved from boiling only by the extreme pressure) upper surface ...
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Behaviour of volcanic eruptions and lava under a high-pressure supercritical water atmosphere
It is hard to be certain exactly how water would behave under such extreme conditions, but among other things it would depend on the temperature of the magma and particularly on the composition of the ...
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Habitable world with abnormally low Argon
Your planet took a very long time to accreate
When you look at any of the inner planets, your argon levels are way higher than this because argon is heavier than Oxygen and Nitrogen; so, it is less ...
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Climate types for large volcanic islands on tidally locked planet
For the sake of clarity in this answer "summer" is when the dwarf facing side of the planet is also illuminated by the yellow star, "deep winter" is when the yellow star is on what ...
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Accepted
Habitable world with abnormally low Argon
Secondary atmosphere, the planet isn't young and hasn't been artificially tampered with but it's atmosphere is much younger than expected. Earth is on it's second atmosphere, we don't know anything ...
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Venus’ LIP period starts today, can we save the Venusians?
Nowhere in the question does it mention evacuating Venus to space, I'm not sure why all the answers are focused on that. Instead, assuming Venus has a few decades, humanity's goal should be to slow ...
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Venus’ LIP period starts today, can we save the Venusians?
The vast majority of Venusians will die, but I think answers suggesting the entire species is doomed are too pessimistic, for the following reasons.
Our space programs in real life are so slow to ...
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Do temperature variations make trains on Mars impractical?
Before we consider track expansion, it may be worth thinking what sort of track we are using.
Mars has about a third the gravity on Earth. A train will have the same mass and momentum as on Earth, but ...
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Do temperature variations make trains on Mars impractical?
The solution is simple: Just include expansion joints (known as Breather Switches in railway parlance) in the rails.
The diagonal joint between separate rails will allow a significant amount of ...
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Do temperature variations make trains on Mars impractical?
Tracks are possible. And you don't even need new technologies.
120C of temperature difference will give a tensile or compressive stress of about 300 MPa, and steels can have tensile strength in the ...
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Do temperature variations make trains on Mars impractical?
Prerequisite
Even though the question states "current tech", I take a running Mars economy (several "cities", industry etc.) for granted here, making all necessary materials, tools,...
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If Venus had a sapient civilisation similar to our own prior to global resurfacing, would we know it?
As an addition to the existing answers, exploring the geology of Venus might not be economically impossible for ever. We will be developing robots that can do most of their own construction and ...
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Venus’ LIP period starts today, can we save the Venusians?
I can't argue with @L.Dutch's answer (which I up voted). Moving an arbitrary number of people in a developed civilization of billions can't be done.
But that's unbelievably boring and I'm not an ...
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Venus’ LIP period starts today, can we save the Venusians?
Yes, but not in their current form.
Venus' atmosphere could be reproduced on a small scale, but it's hot (464C, 867F), high pressure (96 Barr) and very, very corrosive (CO2 atmosphere with sulphuric ...
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