73
votes
Why do Jupiter’s moons have so much water?
tl;dr: They have more water because they captured it as ice, and it’s easier to hold onto ice than water vapor. Planets (and by extension, moons) beyond the frost line were formed with ice as a part ...
- 3,404
48
votes
Accepted
Could liquid water have existed in open space 15 million years after the Big Bang?
Let's interpret your question to be about whether the conditions would permit blobs of water to remain liquid, whether or not water existed yet. And the answer is No, because the pressure was by then ...
- 3,944
27
votes
Why there are no terrestrial planets with a subsurface ocean?
Some hypothesize that the Earth did have a subsurface ocean during the Cryogenian period, which lasted from 720 to 635 million years ago. The Cryogenian saw the two greatest known ice ages in the ...
- 34.1k
21
votes
Could liquid water have existed in open space 15 million years after the Big Bang?
As others have mentioned in the comments, there wouldn't have been any oxygen to form water. Soon after the Big Bang, the protons were hot or dense enough to fuse up to helium and some lithium but ...
- 2,847
19
votes
Accepted
Is the water underneath Europa's ice cap potable?
According to this 2007 paper, the current research as of the time of their own research had a huge range in possible concentrations of $\text{MgSO}_4$, magnesium-sulfate, with over four orders ...
- 3,269
16
votes
How would ocean tides work on a tidally-locked planet?
Since the tidal bulge is always in the same place, how would that affect ocean tides?
The concept of tidal bulge is a useful fiction, but fiction nonetheless. For an object in an eccentric orbit, the ...
- 34.1k
15
votes
Can a comet orbit a planet?
Its very unlikely for a comet to become a satellite of an inner solar system planet. Much less likely than it is for an asteroid. Most asteroids are on fairly circular orbits, and so the relative ...
- 126k
15
votes
Accepted
Why there are no terrestrial planets with a subsurface ocean?
The terrestrial planets are Mercury, Venus, Earth and Mars. Mercury and Venus are too hot for liquid water to exist at any level, Mars has lost nearly all its water and Earth has a surface ocean, not ...
- 126k
13
votes
Salinity of Martian water 3.5 Billion years ago
The article "Water Activity and the Challenge for Life on Early Mars" finds that the early Martian ocean would have been acidic and almost as salty as the dead sea.
The estimates for ...
- 126k
11
votes
How can "Geysers" on Europa reach heights of 100km?
Technically those aren't "geysers" on Europa, they're cryovolcanos. Though that definition may be a bit imprecise as well, but the 100 km eruptions on Europa probably have more in common with ...
- 24.1k
10
votes
Can a comet orbit a planet?
Given that moons commonly orbit planets, why do we never encounter a comet orbiting a planet?
By definition, it would no longer be a comet, but rather a moon (or more properly a satellite). Comets ...
- 15.1k
9
votes
Accepted
Can Liquid Water exist on Mars?
Liquid water can in principle exist at many locations on present-day Mars, but there are a few interesting twists to the story.
At low elevation, the atmospheric pressure is high enough. The triple ...
- 216
8
votes
Accepted
Would drinking melted ice water from Mars taste like sparkling water?
Any ice that forms from water will be free of salt -- the process of crystallization does an excellent job of removing impurities.
But that's only when freezing out of liquid water, which is not a ...
- 7,650
8
votes
Accepted
Can a habitable planet be smaller than 0.58 Earth radii?
Short Answer:
In part Two of the long answer below, it is stated that a planetary mass object needs to have a mass of at least 0.1, 0.12, 0.23, or 0.25 Earth mass to be habitable. Worlds with those ...
- 7,739
7
votes
How can "Geysers" on Europa reach heights of 100km?
I wanted to throw my hat into the mix to flesh out another contributing factor. One reason these "geysers" are so capable of achieving great heights is a lack of atmosphere on Europa to slow them down ...
- 15.1k
6
votes
Why there are no terrestrial planets with a subsurface ocean?
There are no terrestrial planets with subsurface oceans because of differentiation. Denser materials move toward the center of the body. Iron is denser than rock which is denser than water which is ...
6
votes
Is the water underneath Europa's ice cap potable?
Since water on all planets is in contact with impurities, I would think that the default for water is salty, and a small percentage on Earth (2.5%) gets desalinated by going through the evaporation/...
- 3,455
6
votes
When did the first liquid water settle on planets?
The question of water delivery to Earth, and planets in general, is one that is hotly debated!
Let's start by using Earth as our benchmark. The total amount of water on the Earth's surface is around ~...
- 1,386
6
votes
Is Venus in our sun's habitable zone?
What are the inner and outer edges of the Sun's circumstellar habitable zone or Goldilocks zone?
Here is a link to a list of about a dozen estimates made in the last 60 years, some using complex ...
- 7,739
6
votes
Why don't scientists believe Earth's surface water came up from the mantle?
If the question is actually "why don't any geologists believe that Earth's surface and near-surface waters were brought up from the Earth's interior?", then the premise is false since many ...
- 771
5
votes
Accepted
Water Ice on Meteorites
It looks to me that you probably have some misunderstanding of the term meteorite. A meteorite is a remnant body which has reached the surface of a major or minor body (a planet, a moon, an asteroid, ...
- 300
5
votes
Accepted
What would happen if we released water into deep space?
Liquid water can't exist in a vacuum. Water in space (atmosphere, no gravity) tends to form into a ball, but take away the atmosphere and it would rapidly fly apart. It actually wouldn't look like ...
- 24.1k
5
votes
Accepted
How would water-ammonia oceans behave?
It's a big question, but kind of a favorite subject of mine, thinking about exoplanets, so I can give a ballpark answer, and I invite anyone to give correction or give a more technical answer if they ...
- 24.1k
5
votes
Can Liquid Water exist on Mars?
Had you asked a couple of months ago the answer would be "probably yes", now it is more "maybe".
Pure water could not exist in the Martian Environment. The pressure is too low, so the water would ...
- 126k
5
votes
Why there are no terrestrial planets with a subsurface ocean?
We may regard Earth's ocean as a subsurface ocean that has melted through. Temperatures on Earth's surface are too warm to maintain the global ice covering which, on the outer-planet moons, renders ...
- 1,211
5
votes
Is the water underneath Europa's ice cap potable?
The most popular hypothesis for explaining the various zigzagged lines (lineae) that cover Europa’s surface is that they are caused by cracks appearing in the ice shell because of tidal deformations, ...
- 7,549
4
votes
Can a comet orbit a planet?
Yes. See Split comet Shoemaker-Levy 9 became a satellite of Jupiter Ríse hvezd, Vol. 74, p. 224-225
and The Century of Space Science
comet Shoemaker-Levy 9 which was probably captured into a ...
- 236
4
votes
Accepted
Can fish and other sea creatures survive in watery planets like Neptune or any other planets that has water?
Being an ice giant, there is no water on the surface of Neptune. Having a surface temperature of $-201$ $^oC$ any water on Neptune will be frozen. Extraterrestrial liquid water is believed to be ...
- 2,169
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