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Questions tagged [planetary-science]

The study of planets, asteroids, comets, etc, including weather, geology, composition, etc. This tag should be used when the focus of the question is on the the science of a non-Earth non-star natural object, and not used when designing spacecraft to cope with said challenges.

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67
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3answers
42k views

What will be the effect if we stand on Jupiter?

As we all know Jupiter is a gaseous gas giant and it has a large mass, almost twice the sum of all other planets in the Solar system. So, if it happens that we go to Jupiter and as we know it does not ...
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Could we breathe an atmosphere that is not nitrogen based?

As I understand it, the important part of Earth's atmosphere that we breathe is the oxygen. However, Earth's air is only about 21% oxygen with the rest made up of about 78% nitrogen and 1% other gases,...
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Is it possible for a moon to have a higher surface gravity than the planet it is attached to?

Is it possible that a moon has a higher surface gravity than its planet? I guess it would mean that the moon has a higher mass, but then it would be the planet gravitating around the moon and the ...
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If there's nothing special about Pluto, why was it discovered so early?

Pluto was recently re-classified, losing its official status as the ninth planet, because a bunch of other dwarf planets were found in its orbital region that were too numerous and insignificant to ...
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Is it true that NASA is hiring a new 'planetary protection officer'?

NASA is hiring a new 'planetary protection officer' to defend Earth from alien matter, and the pay is a six-figure salary: as much as $187,000 a year. When we are not sure whether aliens exist, why ...
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Could the Moon keep an atmosphere?

When we think of terraforming a body in our galaxy Mars gets lots of consideration as the closest potential body. But what about the Moon? It is currently beyond our ability to add an atmosphere ...
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Why is the rotation rate of Venus so slow?

Venus has an extremely slow rotation rate, to the point that it actually rotates slower than it revolves around the sun. In other words, its day is longer than its year. With the exception of Mercury, ...
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Why are probes that tend to explore outer system always launched to go outwards instead of straight upwards or downwards?

Let's take a look at the trajectory of variety probe missions. New Horizons and Ultima Thule will be 4.1 billion miles away when it visits the Kuiper Belt object. This chart shows the path of New ...
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What is the deepest we have penetrated a terrestrial body other than Earth?

Curiosity drills 6.4 cm (2.5 inch) holes on Mars. Comet harpoons have been proposed for future space probes. There are a number of ways in which we can penetrate the surface of terrestrial bodies, but ...
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Can I harvest diamonds from the rain of Saturn and Jupiter?

A recent news article on BBC News indicates that 1,000 tonnes of diamonds a year are being created on Saturn This is like science fact that screams it must be Science Fiction! Assuming the ...
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How can Mars have dust storms with such a thin atmosphere?

Mars, as I understand, has a very thin atmosphere. However, it still has weather like this: What causes the thin atmosphere to move fast enough to cause such a monster wave of dust?
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Is water on Mars the same as Earth water?

I would like to know how similar Mars water is to Earth water. Can we survive on Mars with Martian water without any major health issues etc?
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When is the next Outer Planet lineup (Voyager)

If I remember correctly, The construction and launch of the Voyager spacecrafts in the early 1970s had an urgency as there was to be an unusual lineup of the outer planets (Jupiter, Saturn, Uranus ...
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Why is the Far Side of the Moon so different from the Near Side?

Here's a photo of the Far Side of the Moon Compare that to the Near Side: Why the difference between the two? The difference is quite significant.
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What defines the radius of a ball of gas like Jupiter?

I've seen statements to the effect of: "the gravity on the surface of Jupiter is about 2.5 times that of Earth". The problem with such a statement is that as essentially a ball of gas, Jupiter is not ...
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Why was Titan the first celestial body beyond Mars to be landed on?

If my memories are accurate, then there's only one celestial body beyond Mars, on which any man-made device was landed. Pictures made there are, in fact, quite popular among space fans. But why Titan?...
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Can it be said that Venus is covered by an ocean rather than atmosphere?

At Venusian temperatures and pressures, CO2 becomes supercritical. This means it behaves as a dense liquid yet has no clear upper bound and continuously becomes gas with height. Can we thus say that ...
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1answer
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Why did the Earth based observations of methane on Mars go wrong?

ScienceNews states that: Scientists had previously identified methane on Mars using Earth-based telescopes and spacecraft orbiting the Red Planet. In 2003, researchers detected a ...
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Did the Mars rovers actually confirm the gravity of Mars?

For years the theoretical calculated gravity of Mars has proliferated science texts and Internet documentation - but did the rover actually do a test to confirm the theoretical gravity is truly equal ...
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How fast does Roche limit disintegration proceed?

The answers to this question about encounters with Jupiter keep mentioning the Roche limit, inside which solid objects break up due to tidal gravity gradients. Over what time scale does this effect ...
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What is the mysterious “Ball of Mars”?

A recent picture of Curiosity rover depicts a surprisingly accurate sphere on the surface of Mars. What is it, and how is it possible that it is so perfecly spherical? Photo by NASA Mars Science ...
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1answer
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What causes moonquakes?

Despite having very little geological activity, without any active tectonic plates, the moon is prone to shaking shifts. As far as I know, moonquakes can be caused by the Sun, thermal quakes, or by ...
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1answer
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Is it a pure coincindence that the magnetic poles of Earth are near the geographic poles?

On Earth the magnetic poles are near the geographic poles. Does Earth have this situation by pure luck? What is the situation on other planets?
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How large could Hyperion be and stay porous?

Here is a question originating on the Worldbuilding stack. Hyperion is porous, with a density of 0.55 g/cc; a little more than half that of water. from https://www.space.com/20770-hyperion-moon.html ...
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Is NASA launching fewer interplanetary missions?

We were discussing this in the chat room yesterday, and I thought it might make an interesting question. While missions are lasting longer today than they perhaps ever have, it seems like there are ...
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1answer
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Can the Sun set twice during the same day on Mercury?

Mercury's day is only a little bit shorter than its orbital period, the relationship is a 3:2 resonance. However, I noticed that the planet's angular velocity at perihelion, 0.265 arc-degrees per ...
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What is the cause of Saturn's north pole persistent hexagon jet streams?

According to the article on the Cassini Solstice Mission website dating back to December 9, 2009: The six-sided shape remains a mystery. Scientists think the hexagon is a meandering jet stream at ...
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Did we know the gas planets were truly gaseous before Pioneer 10?

I'm asking for historical scientific knowledge of our understanding of the outer planets, which seems hard to come by. Pioneer 10 was the first probe to an outer planet (Jupiter). Before then, did we ...
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How will Juno establish existence of solid core within Jupiter and determine its size?

One of the set goals for NASA's New Frontiers Juno mission is studying Jupiter's interior and determining if this gas giant has a solid core and if, how large it is. This is mentioned several times on ...
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Did the Viking landers detect life on Mars?

The two Viking landers had an experiment on board where they attempted to find life on the planet. The initial results said yes, there was life, but later there were questions raised about the results....
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How hard is the Lunar surface?

The lunar surface visible to us is mostly regolith - space dust, asteroid remains, and what-not. The true lunar surface is below - at depths ranging from a few inches to a few metres. Given that ...
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If a gas giant is far enough away from a sun will it freeze solid?

I am reading a book where a gas giant is coming into our solar system. It was a rogue planet, traveling between stars. Given the knowledge we have now, would we expect a gas giant to freeze solid if ...
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Feasibility of colonising Ceres?

Ceres is a dwarf planet in the midst of the Asteroid Belt between Mars and Jupiter - its location in the Asteroid Belt makes it a good base to mine the riches believed to exist in the asteroids. ...
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1answer
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Where to find the best values for standard gravitational parameters of solar system bodies?

Where can I find the best values to use for standard gravitational parameters of solar system bodies for numerical simulation experiments? Here are two sets I've put together. The first set is from ...
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1answer
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What are the implications if Juno finds that Jupiter has a solid core?

Juno has arrived at Jupiter, and will begin taking measurements to determine if the gas giant has a solid core. But what I cannot seem to find is the implications such a discovery would have. This ...
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1answer
627 views

How strong is the electric charge capacity of Martian dust storms?

In my answer to What would it feel like to be in a Martian dust storm? I assert that Martian dust storms would be best avoided, and as one of the reasons (besides carrying corrosive chemicals like ...
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What would happen if an Earth-sized body encountered Jupiter?

As we all know Jupiter is a gaseous planet so what would happen if an Earth-sized object happened to encounter Jupiter? Would Jupiter engulf the object and make it stay at Jupiter's core? Would the ...
12
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1answer
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Does Venus have doldrums or horse latitudes (latitudes with lower winds)?

Because of all the heat fueling convection cells, Venus has some brisk winds especially in the upper atmosphere (up to 370 km/h). I realize the winds are quite slow at the surface, but are there any ...
12
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1answer
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What are the dark areas on the moon?

The Moon has a large number of dark spots, as can be seen on the photo below (Wikipedia), that differ significantly from the lighter areas. The dark areas often seem to be roundish, but not ...
12
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1answer
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How long have we known Pluto is red?

Recently the New Horizon's satellite has given us some lovely color images of Pluto. When did we first discover that Pluto is red? Secondly, did we suspect its color was red before we were able to ...
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1answer
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How long will it be light on Venus at night?

The atmosphere of Earth bends light such that there is still light after the sun goes down for a period of time. How would such effects appear on Venus, given the thicker atmosphere?
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How much sunlight gets to the surface of Titan? What would astronauts see?

Saturn being at 10 A.U. means sunlight on Titan's cloud tops is about 1/100 that on Earth's. That's 4000 times the illumination of Earth's moon. Titan's atmosphere is described as opaque smog. If ...
12
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1answer
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Could Jupiter's tidal forces be used to generate energy?

Let's say we have a colony on Europa (or any other Jovian moon really). Jupiter exerts a lot of tidal forces on its satellites. Could this force be used to generate energy for our colonists?
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2answers
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Why are the Rings of Saturn so much brighter than the other planets?

It seems to be a given that gas giants have rings. However,Saturn has rings that are far larger than any others in the Solar System, and far more visible as well. What is unique to Saturn that it has ...
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1answer
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Would it be possible to “ride the wave” on Venus?

Update: Newly published paper in Nature Geoscience Atmospheric mountain wave generation on Venus and its influence on the solid planet’s rotation rate has open-access links in Science News, ...
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1answer
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Is there a map or list of all the lava tube skylights the LRO has detected on the Moon?

I have read that so far the LRO has detected about 200 skylights - they appear to be holes into larger spaces below them, which could be lava tubes or domes. I would really like to know where all of ...
11
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1answer
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Why is the SOI of Jupiter less than that of Neptune?

Recently we had a question on gravitational SOI (Sphere of Influence) of planets but the image in answer has a plot showing that the SOI of Jupiter is less than that of Neptune. However, Jupiter's ...
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1answer
387 views

What causes Pluto's atmosphere to recede/collapse?

An answer to this question sparked my curiosity. Pluto's atmosphere seems to come and go depending on its orbital position and distance from the Sun. If the heat up from coming closer to the Sun ...
11
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1answer
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Features on border of a crater & ravine on Mars

This image of the Sirenum Fossae Trough - MGS MOC Release No. MOC2-248 of Mars shows spots on the northern lip of the crater that draw my attention. See the Mars Global Surveyor - Mars Orbiter Camera ...
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What is the science behind the canals of Mars?

A recent BBC news article give a short history on the canals of Mars In the late 19th Century, the American astronomer Percival Lowell thought he saw canals on the surface of Mars. He ...