Questions tagged [planetary-science]

The multi-disciplinary study of the geomorphology, geology, chemistry, meteorology, oceanography, hydrology, astronomy and astrophysics of the planets and other objects within the solar system.

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15
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3answers
5k views

Do other terrestrial planets have "earthquakes"?

I know some planets have storms akin to what we have on Earth although obviously varying in nature. I was wondering if other planets have earthquakes? Since this comes down to plate tectonics (right?...
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3answers
305 views

What are the conditions for an ionosphere to form?

I already asked this on Astronomy SE but did not receive any answer so far: What are the prerequisites for an ionosphere to form? For example, can a planet without any atmosphere have an ionosphere? ...
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Minimum Surface Water for Plate Tectonics?

There is good evidence that the presence of water on a planet's surface is necessary for that planet to have plate tectonics. My question is this: Do we know if there is a minimum amount of surface ...
9
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1answer
272 views

Does the global temperature vary daily (hotter and colder days)?

Earth's current average global temperature (i.e. including hot deserts and cold polar caps) is reported be somewhere between 14°C and 16°C (depending on sources and methods). This temperature varies ...
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2answers
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What would happen if you hypothetically happened to touch an aurora

I think that if you touch an aurora it will give you radiation damage? But then the solar winds at -90C would freeze you, so speaking metaphorically what would happen?
3
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2answers
715 views

Would a nuclear explosion over one of the Earth’s magnetic poles momentarily disrupt/weaken the Earth’s magnetic field?

If say the Tsar Bomba had been detonated directly over one of the Earth’s magnetic poles at ground level, would the nuclear electromagnetic pulse generated from that blast have had any momentary ...
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4answers
4k views

Carbon dioxide on Mars, Venus and Earth

Earth's atmosphere is 0.038% carbon dioxide. Mars's atmosphere is 95.3% carbon dioxide. Venus's atmosphere is 96.5% carbon dioxide. If Earth's climate is controlled by CO2, then why is Mars so cold ...
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0answers
70 views

Would the Gaia hypothesis have any practical use?

I recently stumbled upon the Gaia hypothesis, which briefly states that the Earth itself is a living organism. I am wondering: Would this hypothesis have any practical use? Does it make any ...
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3answers
528 views

In an Earth-like planet with no history of carbon-based life forms, would there be limestone?

The extent of my understanding of limestone is about what Wikipedia says at the very top of the page: Limestone is a sedimentary rock, composed mainly of skeletal fragments of marine organisms such ...
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0answers
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Can a cryovolcanic eruption be as powerful as a normal volcanic eruption?

The most powerful volcanic eruption in recorded history was the 1815 eruption of Mount Tambora, an explosion equivalent to 33 billion tons of TNT. Is there any way a cryovolcanic eruption could be as ...
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38 views

How long will it take for plate tectonics to shut down and what will the effects be? [duplicate]

As the interior of the earth cools, presumably there will come a time when the temperature gradient is insufficient to maintain the mantle plumes and hence plate tectonics. How long will this take ...
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2answers
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How would a world entirely covered in oceans get the nutrients to support life?

On earth nutrients flow from the land to the ocean. Life on oceans need those nutrients to trive. I was trying to think how an ocean world might support life if there was no land to provide the ...
3
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2answers
253 views

How to graph gravity as a function of depth, given radius and density?

I need to do this for a planet that has uniform density, and a planet that has two layers. For the first part, I was given that the density was 550 kg/m³, so I made one column in an Excel spreadsheet ...
3
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0answers
329 views

Puzzle using relative dating principles

This isn't directly looking at a real life ecological example kind of thing, but it requires knowledge of relative dating, so I thought I would come here. Here is what was told: -"Worms" (curved ...
7
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1answer
541 views

What "g" would be needed to keep helium on Earth?

I know that helium is a very light and rare gas on Earth because Earths gravity is not strong enough to keep it. Instead, helium and hydrogen are rising through the atmosphere and escape into outer ...
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2answers
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What sort of climate zones would be present if Earth was tilted like Uranus?

The three main climate zones on Earth are tropics, temperate and polar. Due to Earth's axial tilt, the three zones experience different seasonal patterns: The tropics experience 2 or 4 wet/dry ...
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3answers
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Why does the earth spin clockwise?

Why does earth rotate in a clockwise direction? Did a large meteor collide with earth causing earth to rotate? If that is what happened, could another, larger meteor cause earth to reverse its ...
3
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3answers
578 views

Eclipse, Hurricanes, Earthquake....Related Events?

Forgive my ignorance, I'm out of my depth. My wife has pointed to the upsurge climate and geological activity post Eclipse. My immediate response, at least inwardly, was to reject her suspicion. ...
3
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1answer
205 views

Why are storms relatively short on Earth?

From reading articles and the such it is clear that other planets such as Jupiter have storms that lasts months over months. However on Earth, storms last much shorter. In fact, the longest storm was ...
4
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0answers
153 views

Did Theia collide directly with proto-Earth?

I was learning about the formation of Earth on Kahn Academy where it was mentioned that a protoplanet named Theia had a glancing impact with the earth and formed the moon. It seems like there is also ...
4
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1answer
386 views

How can scientists measure chemical composition on other planets?

How can scientists measure chemical composition (oxygen, nitrogen etc) and temperature on other planets without being there?
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2answers
2k views

How far up do you have to go before most of the atmosphere is below you?

If I wanted to make an air shield around the earth to contain exactly half the planet's atmosphere (by mass), how far above sea level would I have to build it? It's slightly complicated to me because ...
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6answers
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Are there any photographs of mountains without significant erosion (on Earth or otherwise)

I'm curious about how mountains on an airless world such as the Moon would look if you were standing on the surface and looking at them. There are plenty of artists' impressions, of course, but I'm ...
9
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2answers
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How does the Sun heat the Earth?

The core of the sun has a temperature of 15,000,000 °C. The surface of the sun has temperature around 5,000 °C. The sun is around 93 million miles (150 million km) away from earth. My Question: With ...
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3answers
582 views

Which physical parameters can we actually measure to confirm the existence of the Greenhouse Effect (GHE)? [closed]

The theory of a GHE in a planetary atmosphere is rather well known. Many claim it is no longer a theory but actually proven as a fact. However I have been reading a lot of things Richard Feynman said ...
8
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1answer
444 views

How do tectonics work on other planets?

What kind of tectonic plate activity exists on other planets in the solar system, or even large moons? Are there any deeper studies of what is needed for a planet or large moon to have tectonic ...
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2answers
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Plate Tectonics: Is it possible to have an ocean-continent divergent boundary

I am procedurally generating planets for an open world space sandbox game. I am using a rough simulation of tectonic plates to create mountain ranges and other geological features. A planet surface ...
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2answers
138 views

Terrestrial Day vs. Venusian Day: Why the Huge Time Difference?

The diameters of Venus (7,520.8 miles) and Earth (7,917.5 miles) are comparable, but the disparity of the length of the day for each planet - as expressed in terrestrial hours - is enormous; a day on ...
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2answers
655 views

Was there once a glacier over Starcke national park in Queensland Australia?

I was randomly exploring Google Earth when I came across some sort of rock formation in northern Australia. The location of the rock formation with respect to Australia is shown below. It is in or ...
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2answers
1k views

How long it takes to cool a planet?

Suppose a planet like Earth or Venus is totally isolated from sunlight. How quick would it cool down? On Earth it seems to me that the air temperature drops significantly even during a night. Does it ...
5
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2answers
215 views

What is the CI chondrite concentration of REEs/rare metals, in ppm/grams per ton?

I am researching the abundances of rare earth elements and rare metals in meteorite samples, because I want to investigate the notion that asteroids represent abundant stocks of rare resources. The ...
5
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1answer
119 views

doubt about the 'white spaces' in the maps from satellite

I have a doubt about the 'white spaces' in the maps from satellite. For example, for the atlantic areas I have plotted AOD and appear many areas where sistematically do not have any data (white spaces)...
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5answers
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How do we know the asteroids formed at the same time as earth?

In continuation of the question Why is Earth's age given by dating meteorites rather than its own rocks?, what evidence do we have that the asteroids indeed formed at the same time as earth? Is there ...
8
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1answer
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Melting basalt on the lunar surface - what would the resulting material be like?

The idea is to melt the fine-grain portion of basalt regolith using a large Fresnel lens, and let it cool to a solid. The lens would track along a tamped bed of material leaving a molten puddle ...
3
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1answer
275 views

How does water still exist on the Earth?

Almost all the theories that explain the origin of Earth says, it was way hot back then. That means It was in a lava state in its early days. Then gradually cooled down to the current state. If ...
4
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3answers
771 views

What natural phenomena increase stratospheric ozone?

Most of us know that the ozone layer gets depleted due to green house gasses and other factors. Which made me wonder, is there any natural phenomenon that causes an increase in ozone?
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2answers
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Geomorphology of Mountains With Wind only Erosion

I am curious what mountains would look like if erosion occurred almost entirely by wind. Specifically, I am curious of how granite mountains would look on a "snowball" terrestrial-sized xenoplanet. ...
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0answers
369 views

What is a weather system?

I heard on Star Talk Radio that Jupiter has weather systems larger than Earth so I was just curious to know what the definition of a weather system is exactly.
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1answer
2k views

Why do Earth and Venus have different atmospheres?

Venus appears to be the closest to Earth in mass, density, size, etc. - though they clearly have different atmospheres. Why do Earth and Venus have different atmospheres?
13
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1answer
226 views

Phase changes deep in planetary interiors and their implications for surface tectonics

Earth's core mantle boundary represents a phase change from a solid (though convecting) mantle to a liquid Iron/Nickel core. This dramatic transition is likely the origin of the D" boundary, as well ...
14
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1answer
184 views

What kinds of remote sensing required to observe methanogenic life on Titan?

Inspired by Chris McKay's Possibilities for methanogenic life in liquid methane on the surface of Titan. In the paper, the PI's found that the consumed acetylene, ethane, and other organic solids ...
9
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2answers
330 views

Impact craters vs volcanic explosions on Mars

A maar is a shallow volcanic crater with steep sides that is surrounded by tephra deposits. The tephra deposits are thickest near the crater and decrease with distance from the crater. Source: http://...
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1answer
50 views

Stars twinkling [closed]

What is the science behind the vigorous glow of stars ? Since 2 days I was observing one of the stars in blue and red colour I just want to know what is the speciality of that star?
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3answers
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What are the criteria that make a planet (in)habitable?

Recently, I realized a lot of factors must contribute toward making a planet habitable, other than just the ones that come to mind like having oxygen, the right temperature, and so on. What makes a ...
5
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1answer
300 views

What are the relative contributions of planets to the Milankovitch Cycles?

When reading about the Milankovitch cycles here, it says: If the Earth were the only planet orbiting our Sun, the eccentricity of its orbit would not perceptibly vary even over a period of a million ...
9
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1answer
208 views

What is the current status of geophysical global cooling theory?

Plate tectonics effectively rubbished the theory of geophysical global cooling as a means of explaining many surface features on the Earth. However, this wiki says that the same process is responsible ...
4
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1answer
284 views

Source of sub-surface ringwoodite water

I was reading about the discovery of vast amounts of water locked up in ringwoodite (see here). The authors of the study seem to suggest that previous ideas, involving water deposits being delivered ...
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1answer
400 views

How will axial precession affect the weather in the northern hemisphere (UK latitudes)?

Unless there's a twin star to our sun in which case axial precession might be an illusion the Earth's wobble won't effect the total amount of energy received from the sun as is expected from increased ...
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1answer
97 views

Are oceans a major factor in creating high winds on a planet?

This question only pertains to oceans of water and how much they account for the process of creating high winds on a planet with any type of atmosphere.
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6answers
3k views

Would life on Earth survive without the Sun?

Would life on Earth survive if Sun wasn't there? My teacher told me that there are chances that it would but there would be a lack of gases and chemicals and photosynthesis that occurs with light at ...