# Questions tagged [mars]

Questions regarding Mars, the fourth planet from the Sun.

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### Is the 1970's Viking Orbiter due to contaminate Mars?

From Wiki: The Viking program ended on May 21, 1983. To prevent an imminent impact with Mars the orbit of Viking 1 orbiter was raised on August 7, 1980 before it was shut down 10 days later. Impact ...
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### Is dust the only reason why the Martian sky is so bright?

The atmospheric pressure on the surface of Mars is 0.00609 atm on average and 0.012 atm at most in the Hellas Basin. On Earth, at these pressures, which are found at altitudes about 30-35 km (19-22 mi)...
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### Who coined the phrase “martian dichotomy”?

This question is adjacent to this other one. The martian dichotomy refers to the fact that the northern and southern hemisphere are radically different on Mars, with different surface ages and ...
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### When was the martian dichotomy first observed?

The North and South hemispheres of Mars are very different one from another. They have different elevations, different crust thickness, different surface ages. This is known as the martian dichotomy. ...
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### What is 'surface acceleration' of a planet or other body? As opposed to its 'g' (gravity)?

The Mars Fact Sheet at NASA (their NSSDC or NSSDCA section, whatever that means) lists a value for 'surface acceleration' just below one for 'surface gravity'. They also have the values for Earth, ...
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### How many quakes have been detected by Insight?

Insight has been on Mars with its seismometer for almost two years now. Has it detected any mars-quakes yet? How often do these quakes seem to occur? Is there a website where the current number of ...
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### Could life forms have travelled between the Earth and Mars on meteoroids?

Mars meteorites have been found on Earth, and there likely are Earth meteorites that have crashed on Mars. If you take any random piece of rock from the surface of Earth, the odds are there will be ...
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### What are the most recent minerals modified by water found to date on Mars?

There likely was quite a bit of liquid water on the surface of Mars less than 4 billion years ago. We know this because we found rocks that old that have been modified by the presence of water. For ...
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### How to retrieve from NASA Horizons site the needed data to plot analemmas for other planets?

I posted such a question in space.stackexchange ( https://space.stackexchange.com/questions/46077/which-are-the-correct-input-parameters-for-nasa-horizons-query-to-get-the-right?noredirect=1#...
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### How to see Mars and Venus in color?

My telescope is Arsenal - Synta 70/700 AZ2 (refractor model). 140x max zoom (10 mm with Barlow). I could clearly see Jupiter and Saturn in color. I even saw brown stripes on Jupiter. Yet, when I tried ...
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### How can one determine the angle between the line of nodes and the major axis of the orbit of Mars?

Edit: What I really was looking for, was the difference in longitude on the orbit of Mars between its aphelion and the point where the north pole axis of Mars would point towards the Sun (northern ...
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### How did the orbits of Phobos and Deimos circularize?

The satellites of Mars might be captured asteroids. But Phobos has an eccentricity of $0.015$, and Deimos of $3\times10^{-4}$. If they were captured, they likely were captured with rather eccentric ...
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### How old are the Martian blueberries?

The martian blueberries (only blue in false color) found by the Opportunity rover in Meridium Planis are formed by slow evaporation in mineral-rich liquid water. They obviously formed early in the ...
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### Has any of the orbiters or rover on Mars captured image of comet NEOWISE?

We are seeing stunning pictures of comet NEOWISE from earth (and ISS too), are there any pictures captured from Mars by an orbiter or rover, or any other spacecraft?
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### Why wouldn't massive torrents freeze on Mars?

I am currently reading the Cambridge Guide to the Solar System. In chapter 8, section 8.7, they explain that massive torrents of water created outflow channels on the surface of Mars in the past. The ...
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### Is there permanent dry ice on Mars? [duplicate]

Are there any places featuring permanent dry ice (carbon dioxide ice) on Mars? Is there dry ice at the poles?
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### Ice filled craters on Mars

How many craters on Mars have ice in them and which ones have permanent ice? I could only find Korolev and the unnamed one - strange for such a remarkable crater. http://www.esa.int/...
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### Age of Jezero crater on Mars

How long ago the Jezero crater was formed on Mars? And is it a meteorite impact crater?
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### How to easily find out the periods when a planet gets into retrograde?

How to easily find out the periods when a planet gets into retrograde? for eg I want to find out all the periods, in last 5 thousand years, when mars goes into retrograde in Sidereal Scorpion? Is ...
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### Is it possible to find what crater the Mars meteorites come from?

A few dozen meteorites have been determined to come from Mars. These meteorites likely formed from three separate events. Each one of these events must have created a big enough crater that rocks ...
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### Does the axial tilt of Mercury and Venus vary?

The axial tilt of Mars varies greatly over time, with a tilt varying between 15 and 25° over the last million years, and varying even more over the last 5 million years. The Earth's tilt on the other ...
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### Has the inclination of the orbital plane of Phobos and Deimos followed that of Mars' axial tilt?

Phobos and Deimos are very close to Mars' equatorial plane (the inclination of their orbits is roughly 1°). The axial tilt of Mars has changed a lot over time, and might have had a inclination of over ...
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### Retrograde Motion: Stars in the background

I was reading about the retrograde motion of Mars. All explanations give reference to the stars in the background. But I do not understand why this is necessary. I say this since stars themselves also ...
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### Retrogradation movement of planet Mars relatively from Earth by Copernic

I have a simple question : on the following figure: I don't understand on the right figure why there is a progressive shift on the right when we start from step 1) to step 9). I guess there is an ...
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### Eclipses on Mars

This amazing video shows an annular eclipse of the Sun by Phobos as seen from Curiousity. This one shows an eclipse by Deimos. My question is do these things ever both happen at once? Do you ever get ...
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### Why does Hellas Basin look white on some maps?

One map of Mars I see a lot is this colourized map: the Viking colourized global mosaic: (Source) But one thing which strikes me as odd is just how white the Hellas Basin is (the white patch which ...
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### Are there Earth rocks on Mars?

Certain meteorites found on Earth have been established to come from Mars: a giant impact ejected rocks from Mars, these rocks traveled through interplanetary space, and went through the Earth's ...
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### When and how was the length of a Mars year determined?

I guess it is known for a long time that Mars has an orbital period of around 687 days. But when and how was this determined?
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### Is it possible to revive the Mars geodynamo? [closed]

I’ve done a bit of reading and have found multiple theories suggesting how the Mars geodynamo stopped fully working. This site suggests that one possibility could be volcanic activity ejecting water ...
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### Does rusty iron on Mars have tetanus? [closed]

Since the surface of Mars is covered with lots of iron and became red because of rustiness of iron, Source from: live.mrf.io if we do have plan to live there, can we get tetanus on those rusty thing?...
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### Why are only some of the geologic features in Mars' Noctis Labyrinthus region named?

I found this page Names Approved for Six Cavi and a Tholus on Mars which lists seven features on Mars. I'm curious about the decisions to name only these features: Dalu Cavus, Layl Cavus, Malam Cavus, ...
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### Martian dust storms-what was the smallest in area, or shortest in duration storm detected?

I understand localized Martian dust storms can develop into global wide events. All searches I do produce results that focus on local storms expanding. Is there any information on what was the ...
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### How many meteorites have been found some place other than Earth? Where is an authoritative list maintained?

Backgound: After seeing this tweet by astronomer Kacper Wierzchoś about our not-so-new but at least newly-discovered "mini-moon" I scrolled down and saw the tweeted image below. The object is the ...
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### How to understand the meaning of this International Occultation Timing Association (IOTA) lunar occultation of Mars map?

Earthsky.org's Watch Mars disappear behind the moon on February 18 as well as Moon occults Mars morning of February 18 include the image below and credit it to The International Occultation Timing ...
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### How can I find the depth of a portion of the Valles Marineris?

How can I find the depth of the low lying part of this image of the western part of Valles Marineris? I'm interested in the area northeast of Noctis Labyrinthus, southwest of Tithonium Chasma, north ...
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### How does the surface gravity on Mars vary between the equator and its poles?

A day on Mars is similar in length to the Earth's day. On Earth, due to rotation, the surface gravity varies from 9.78 m/s² (0.997 g) on the equator to 9.832 m/s² (1.003 g) on the poles. I wonder how ...
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### Are Tharsis Montes and Hellas Basin a result of the same event?

Looking at Mars map: the highest, biggest mountains and their associated highlands are essentially antipodes of the deepest, huge basin. Roughly 180 degrees away, similar latitude except opposite ...
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### Orbitally convenient Mars-to-Earth transit times?

Are there any peculiar solar system layouts that would result in highly efficient transits between Mars-to-Earth? I am aware of a Hohmann transfer orbit, but can other planets be used to "sling-shot" ...
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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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### Is there a general term used to identify the high flat features within Noctis Labyrinthus on Mars?

At the western end of Valles Marineris, where it mets Noctis Labyrinthus (highlighted section of image) there are a series of flat geological formations between the canyons. Is there a unique term ...
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### Why are we so quick to proclaim the geological inhospitability of other planets based on extremely minimal information?

Now, I'm not questioning claims that any planet in the Solar System is atmospherically or externally inhospitable, but claims made that other planets have geology that is extremely hostile to ...
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### At Mars' equator how long does twilight last?

With Mars' thinner atmosphere I'm assuming twilight would not last as long compared to the duration on Earth. Has there been any determination of the length of twilight on Mars at the equator or any ...
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### Would Martian sunrise/sunset look the same at the Thaumasia Plateau as the rovers' photographs?

If observing the sunrise or sunset, with the naked eye, from the Thaumasia Plateau (app. 260°, -10°), 6 kilometers above Mars elevation zero, would it have the same blue hue as the images of the ...
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### Are meteors visible on Mars?

If a person were standing on the surface of Mars, under ideal viewing conditions for seeing a meteor: no clouds, the sun has long set, would a meteor be visible to the naked eye considering how thin ...
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### How long is the Sun closer to Earth then Mars is?

A recent question at Space.se has generated a few comments that are interesting. But the answer to one particular comment to might address a lot of misconceptions. I imagine the actual halfway ...
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### How can I download all of this JPL MRO imaging data at once?

There are several files. I think that they all needs to downloaded to have the complete dataset. Is there a particularly good way to download them all in one shot? https://pds-imaging.jpl.nasa.gov/...
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### How was Cassini able to measure and use the Earth-Mars distance to get the Earth-Sun distance?

How was Cassini able to measure and use he distance between Earth and Mars to get the Earth-Sun distance? How were the ratios of Earth-Mars and Earth-Sun calculated then? Given Kepler's laws all we ...
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### 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? ...