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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7
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1answer
153 views

Should we expect the surface rocks of Venus to be oxide poor?

My thinking is that in an atmosphere rich in hot sulfuric acid they couldn't stand a chance. Although I am unsure of what exactly would be going on chemically at the interface between the venerean ...
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95 views

Strategies for scientific objectives aboard small lunar orbiting satellites [closed]

We are designing a small satellite lunar mission. In the preliminary design submitted for approval, most of the focus was on technological demonstration of acquired COTS hardware, flight systems, ...
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1answer
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Does the temperature near the surface of the Moon rise rather quickly with depth?

I have heard presentations on lunar lava tubes that estimated the temperatures of the ground surrounding them as being well below zero. An article in NASA Science News says this: Once you get down ...
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2answers
298 views

How can I find a daily record of the temperature on Mars?

Does any probe or lander track the temperature on Mars, and is this data published anywhere? I recall the MGS used to issue a "Martian Weather Report", but it has ceased operating.
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2answers
455 views

Where do ice giants contain ice?

There is a class of planets called ice giants. Let's talk about Neptune. The top layer is atmosphere, consisting of hydrogen and helium. The amount of these gases is about 10% but they produce high ...
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1answer
298 views

Mars: Readily usable sulfur for sulfur concrete?

Sulfur concrete is a mix of sulfur and aggregates that make a strong, quick-hardening concrete that is likely to be used for construction on Mars, which has a great deal of sulfur. Most experiments, ...
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1answer
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Is there salt in space?

Is it possible for ordinary table salt (sodium chloride) to form on a lifeless planet / moon / comet / other body? Is liquid water required? Would it be common or nearly-impossibly rare? Part of a ...
4
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1answer
753 views

How to produce oxygen out of Venusian atmosphere's carbon dioxide?

What are the possible methods of in-situ extraction of oxygen from the atmosphere of Venus, which is mostly carbon dioxide?
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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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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 ...
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2answers
220 views

How can an orbiting spacecraft's motions yield the orbitee's deep structure?

I've always been a fan of satellites like GRACE and GRAIL, where two satellites orbit a body, precisely measuring the changing distance between them in order to sense gravitational anomalies caused by ...
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How do domes in lunar impact melts develop, and might they be hollow?

On the floors of young craters of the Moon, smoothly rounded domes are visible in some spots. Lalande crater has 4 of them, each around 200 m across. Here are less regular ones on the floor of ...
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1answer
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How deep is the regolith around this crater?

I'm trying to estimate the depth of the soil around this 300 m crater about 150 m from the lip of Lalande crate on the Moon's equator. In the image below from the LRO's camera the sun's incidence ...
3
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1answer
287 views

If a high-temperature melt of lunar soil cooled slowly, what layers might appear?

Suppose mare regolith is heated to 2400 K, then left to cool slowly in a tank. Samples of powder regolith from the mare are about half glasses and half crystals of composition as shown below. Would ...
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4answers
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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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1answer
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If Mars had more atmosphere how warm would it be?

Looking at Venus, Earth and Mars, the closer you are to the sun the warmer you are. At the same time the warmer planets also have thicker atmospheres. ...
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Is Hydra of Pluto cut unusually, or just darkened on its surface?

The image of Hydra recently released shows a sharply edged black half oval cutting deep into its bottom as in the image below. Is it dark sky behind an open gap we see, or just unreflective matter on ...
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1answer
193 views

What is the accepted methodology for prioritizing scientific exploration missions?

This question is motivated by an argument that arose in relation to this question. We know there are decadal surveys recommending the priorities in planetary exploration. There is also a neat problem ...
10
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2answers
399 views

When did Kepler roll over and how does it match the anomalies of KIC 8462852?

The Kepler space telescope, during its first mission, rolled over four times per year in order to keep its heat shield facing the Sun. At what dates (in that BJD time format) was this done during the ...
7
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1answer
581 views

Lightning on Mars?

I watched the movie The Martian, and there is a brief scene where there is lightning on Mars. Something about this seems unlikely to me, but I can't remember if it's actually possible or not. Is there ...
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2answers
2k views

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 suggested that ...
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1answer
683 views

Titan - Is the source of so much Methane being overlooked?

Is the source of so much Methane on Titan being overlooked? Tons of very intelligent and knowledgeable people already looked at it, so the answer in undoubtedly "no", so I guess my question is more ...
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1answer
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Why has no lander or rover visited Hellas Planitia on Mars?

While with this weeks discovery, I am sure everyone is waiting for the inevitable trip to Palantir Crater, I noticed that one Mars' largest crater, Hellax Planitia has never been visited by a lander ...
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3answers
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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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1answer
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What makes materials on the Moon look so different when the sun is high?

The surface of the Moon looks very different in orbiter images taken at local noon than it does in images from other times. Here are two examples of the same places in Lalande Crater. In each image, ...
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4answers
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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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2answers
744 views

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
205 views

How Earth-like is “Earth-like”? [closed]

This is about planets on which life as we know it could arise, and how different they might seem to Earth. By "life as we know it", I mean life sharing the same chemical basis as our own - requiring ...
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1answer
694 views

Catalog of lunar crater depths and diameters

What is the most recent and comprehensive lunar craters catalog which contains information about their depths as well as diameters?
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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 ...
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2answers
149 views

Planet building: collision without fragmentation?

Our Solar system poses a significant problem for colonisation insofar that the rocky planets are predominantly on the... small scale; at least as far as mass is concerned (Earth is the exception ...
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1answer
287 views

How do I properly use the LROC Image Search tool?

My current favorite lunar imagery tool is Arizona State's Lunar Reconnaissance Orbiter site. (Sorry LMMP.) It has a section where you can search for imagery by filling out a form, which is great ...
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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
198 views

Measuring the pressure and temperature of Pluto's atmosphere using stellar occultations

Is this primarily done analyzing the Voigt profiles absorption bands on background of stellar spectra or on re-emission bands of atmospheric compounds? Assuming Pluto's atmosphere behaves like an ...
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2answers
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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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1answer
324 views

Why does Jupiter have the colors it does?

This was sparked by an interesting conversation in the chatroom. We were discussing how Jupiter, being made of gas, has a lot of color. Looking into it, I found this statement, from Universe Today: ...
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3answers
7k views

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 ...
4
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1answer
187 views

Do the size of rocky planets determine how hot they are inside?

As I recall, the main cause of the high temperatures inside e.g. the Earth is thermal heating due to the decay of radioisotopes. The thinking is that: Although small, the heat has nowhere to go, so ...
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2answers
665 views

Why is part of this New Horizon's Charon high resolution image missing?

The New Horizons team released the following photo of Charon today This choice of image seems rather odd to me for a number of reasons. First of all, according to Emily's schedule, there were 3 ...
6
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1answer
320 views

When could we see Pluto's Southern hemisphere?

New Horizons just passed by Pluto, but was unable to see the southern hemisphere, as a result of it being in perpetual eclipse. When will the southern half be lit, so that the rest of the planet could ...
11
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1answer
445 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 ...
8
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1answer
556 views

Why does Pluto change color?

This article says [Pluto] is about 20% redder than it used to be. Have there been any further articles/Hypotheses on both the cause of the color, and more importantly, the color change? Or do we ...
13
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1answer
604 views

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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0answers
275 views

Why does the Moon's Anaxagoras crater seem sort of jumbled?

Now that very high resolution imagery of the Moon's whole north, above 60oN, can be viewed on one giant awesome zoomable map, I've been taking a close look at a number of craters. Anaxagoras sticks ...
5
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1answer
615 views

Why are smaller celestial bodies like Ceres spherical?

When we look at larger objects (the Moon, Mars, Earth), they are pulled into spherical shapes by their own gravity. The question I have relates to smaller objects... those close to the threshold at ...
7
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1answer
287 views

Will there be a team of planetary scientists advising the Emirates Mars Mission team?

The United Arab Emirates (UAE) recently announced plans to send a probe, named al-Amal (Hope), into Mars orbit. A new group called the Emirates Mars Mission was created to head this effort. The ...
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2answers
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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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3answers
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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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1answer
422 views

Is this photo of Mars in color?

This recently released terrain of Mars as taken by the Curiosity Rover looks like it was done in black and white. Is this really how it looks like to the naked eye? From here.
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1answer
917 views

A cloud-top colony on Venus, will it drift to the poles?

Suppose a cloud-top colony on Venus. Provided that it has no thrusting engines, where it will tend to go naturally with winds, to the equator, to the poles or elsewhere?