Questions tagged [surface]

Questions about the outermost solid or liquid layer of a celestial body.

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Longest line of sight on Mars

It is said that the slope of Olympus Mons is so gradual that the peak cannot be seen from the plain; it is hidden by the planet's curvature. That provokes questions: How steep is the steepest of the ...
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4 votes
1 answer
63 views

At what point does an astronomical body's surface stop being gas giant-like and start being sun-like?

I've generally seen brown dwarfs depicted as more massive and slightly wider Jupiters in varying colors with banded cloud structures, sometimes hot enough to be visible glowing. I've also seen red ...
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2 votes
0 answers
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Surface composition of Mercury?

I've been doing research on the surface composition of Mercury, but it doesn't seem that there are many helpful results online from ArXiv. One article from PNAS describes the composition of Mercury as ...
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2 votes
1 answer
108 views

When were the spiders first observed on Mars?

On Mars, there are spider-looking features near the South pole that might be caused by CO2 sublimation. When were these features first observed on the surface of Mars?
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6 votes
2 answers
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What are the dark spots in the "face of Mars" picture?

In this picture of Cydonia by Viking 1 (taken from this article), there are a bunch of black spots scattered everywhere. Are they an artifact of the image or are they an actual feature on the surface ...
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32 votes
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Is oxygen really the most abundant element on the surface of the Moon?

I found this infographic that seems to say that oxygen is the most abundant element on the surface of the Moon. Is this really the case? If so, under what form is this oxygen?
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Local atmospheric pressure and surface gravity in Jezero crater?

The Jezero crater on Mars is the target location of the American Mars 2020 mission. I can't find any good values on the local air pressure and gravity, though the elevation is around what is ...
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3 votes
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Surface of the Sun, or Jupiter, etc [duplicate]

I keep hearing and reading statements that refer to the "surface of the Sun" (how hot the surface of the sun is) or the "surface of Jupiter" (when the Shoemaker comets hit Jupiter)....
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4 votes
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What is the surface feature of the mesas in the Noctis Labyrinthus on Mars?

Caveat-my knowledge of geology is limited. Is it known what is the surface like on the larger mesas in the Noctis Labyrinthus? I trust the very smooth looking surface on this mesa is a product of ...
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46 votes
3 answers
11k views

Why is Mars cold?

The surface temperatures of Mars are about -87C to 5C, which is much colder than that of Earth's. If Mars has 95% carbon dioxide, which is a Greenhouse gas, why is the surface of Mars so cold? ...
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9 votes
1 answer
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How would water-ammonia oceans behave?

Scientists strongly suspect that several moons in our solar system have frozen-over oceans of water-ammonia mixture. I've also read speculations on the possibility of surface water-ammonia oceans on ...
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What might the surface of Jupiter's rocky core look like? [closed]

Jupiter is posited, in some models, to have a rocky core about the size of a few Earths. If we could see through the thick gaseous atmosphere, what topographical features might we find on the rocky ...
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3 votes
2 answers
152 views

Are all impact craters circular?

I'm aware for over 100 years the reason has been known how impact craters are almost always circular, but my question really is has there been any recent insights in the area? What other topologies ...
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6 votes
1 answer
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Strange square-like formation on Mars

Recently I've explored an area on Mars' surface which one looks like huge hatch cap & hole, about 10 kilometers, between tons of circular craters. The formation is very unique and strange to me. ...
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6 votes
2 answers
882 views

What colours can rocky planets (or moons) have

I am currently working on a simple program to randomly generate and display rocky exoplanets (for a space based strategy game), but I am having some problems figuring out what colour the rocks of ...
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1 answer
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Are these parallel lines I'm seeing in this image a real pattern on the Moon?

In this question I mention the GIF in EarthSky.org's Moon Phases update Lengths of lunar months in 2017. After watching it a while, I've noticed a pattern of parallel nearly vertical lines on the Moon ...
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1 vote
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How do we get the angular size of a crater without lens?

Suppose I want to calculate the diameter of the crater. I apply the small angle formula $$diameter=\frac{\theta_{diameter}}{206265''}\times D$$ where $\theta_{diameter}$ is the angular size of the ...
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What type of telescope can show cliffs on the moon surface from a city location?

I am a complete novice in this world and I would like a telescope where I could have enough power to view the moon's surface, I don't expect to see the flag or the hover sending signs to me, but ...
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Angles of sunrise and sunset viewed from a surface anyway oriented

I need to understand how to calculate the angles of the sunrise and sunset viewed from a surface oriented against the azimuth and the horizon plane, and for any day of the year. For example, I have ...
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1 vote
1 answer
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What does the surface of Mercury look like?

What does the surface of Mercury look like? What color is it (I have seen some images portraying it grey and some a light brownish color), and would the surface be dusty like the Moon, smooth, or ...
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1 answer
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How to calculate the temperature of a star

I need a way to calculate the effective temperature (surface temperature) of a star for a stellar model. I need something in the form Te=.... I have: Radius in m mass in kg the composition of ...
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What is the color of Venus if it has no atmosphere?

Mars looks reddish and Mercury looks gray because they lack thick atmospheres and we can see their "real color" easily, how about Venus? Is the surface of Venus really yellowish in color?
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Do boulders erode differently on asteroids than on the Moon?

If I understand it correctly, boulders on the Moon are only found near fresh craters, because micrometeorites erode them over time. Asteroids are believed to have formed sometimes even earlier than ...
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4 votes
1 answer
531 views

What is the temperature on surface of Pluto facing Sun?

According to wiki page, the mean temperature of Pluto is 44 degree K (-229 degree C). However, given that Pluto is tilted greatly and there is daylight for long periods on part of Pluto facing the Sun ...
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8 votes
2 answers
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Could Pluto and Charon have extra-Solar origin?

Pluto and Charon seem to have surprisingly young surfaces, considering that resurfacing events were expected to be rare for them. Could the explanation be that they actually are young? Formed later ...
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10 votes
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Could an impact have resurfaced Venus 300 million years ago?

Venus surface isn't older than about 300 million years. The only explanation I've come across is that some kind of global volcanism resurfaced the planet. But couldn't it have been an impact event? A ...
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3 votes
1 answer
307 views

How easy is it to mine water on Ceres?

It has been suggested by some futuristic or sci fi leaning thinkers, that Ceres' surface might be mined for water to support human exploration and settlement of space. But NASA's Dawn mission and ...
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13 votes
2 answers
21k views

What will happen when landing on Jupiter?

Jupiter is a gas giant, so landing on it will not be like landing on Earth, our Moon or Mars etc., as it does not have a solid surface like these. If we have a hypothetical spaceship or probe landing ...
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7 votes
1 answer
181 views

Would bagging an asteroid destroy valuable science about it?

NASA has a plan called "Asteroid Redirect Mission option A". It would robotically put an asteroid of a few meters diameter in a bag and push it into reach of astronauts for thorough examination. 44 ...
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1 vote
2 answers
236 views

Why do rocks on other solar system bodies that have an atmosphere seem to be flat?

Images taken by landers on Titan and Venus and Mars show landscapes where rocks, to me at least, are surprisingly flat. Being used to walking around in forests with roundish meter sized boulders, I'd ...
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8 votes
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How likely and severe is the threat of a gamma ray burst to earth?

In the National Geographic article: http://news.nationalgeographic.com/news/2009/04/090403-gamma-ray-extinction_2.html it is suggested that a gamma ray burst likely caused a mass extinction in earth's ...
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3 votes
0 answers
166 views

Intrasolar planetary surface temperature change divergence from Earth

Considering the vast amount of insulating gas emitted by human activity on Earth without a coincident release on all other planets in the solar system as well as the phenomenon that planets in a solar ...
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3 votes
1 answer
828 views

Is the surface of Venus red hot?

I was wondering, is the surface of Venus so hot that it would glow red in the dark (e.g. on the dark side of Venus)? I am working on making a solar system simulator, and that would make for a great ...
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5 votes
5 answers
272 views

Could there be life beneath the surface of Mars or moons?

I realize radiation and extreme temperatures would probably destroy life on the surface of most planets and moons, but could life exist beneath the surface (e.g. like earth worms on earth)?
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4 votes
1 answer
145 views

Do planetary surface temperatures change in unison in a solar system?

Are there any known correlations between the changes in planetary surface temperatures in a solar system? If so, do the farthest planets have smaller albeit correlated changes?
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10 votes
1 answer
116 views

What observational constraints are there in detecting the presence of volcanism on exoplanets?

This question is somewhat related to my earlier question How are the compositional components of exoplanet atmospheres differentiated?, but this about a specific surface-atmospheric phenomena - ...
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15 votes
1 answer
754 views

Is the surface of TrES-2b actually dark?

The exoplanet TrES-2b is known as the darkest planet ever found, reflecting <1% of the light that hits it. What does it mean in respect to the surface? What would we see below the atmosphere of ...
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