Questions tagged [planetary-science]

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How do the giant planets excite the orbits of asteroids?

The giant planets, particularly Jupiter, are notorious for bringing about changes in eccentricities and inclinations of smaller bodies(asteroids and KBOs). Jupiter, in fact, throws almost all the ...
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Probability of transit of an exoplanet in front of its star

I'm trying to calculate the probability of transit of an exoplanet in orbit around a star of diameter $d$, at a distance of $4d$ from its centre. Here's what I did: In this figure, we are only ...
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Which JWST instrument modes are compatible with observations of the bright trans-Earth planets Mars, Jupiter, and Saturn? Which aren't?

My comment says: ...answers to the Space SE question Can James Webb take pictures of our solar system? In what ways will they differ from/compliment those from Hubble? suggest that at some point JWST ...
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Gamma Ray Spectroscopy in detecting hydrogen

My professor explained saying that bombarding the surface with cosmic rays breaks off a few neutrons from nuclei and the nucleus, having undergone a change in energy level, emits a gamma photon. The ...
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If Theia did collide with Earth, would it have produced rings? If so, would we expect to still see at least some remnants today?

Before I get into the actual question, I'll just specify two things: Few billion years ago, a planet as big as Mars named Theia, is hypothesized to have crashed into the Earth, leading to the ...
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Up to what distance from the Moon does the Moon's gravity hold its exosphere before it is being cast away by solar wind?

Up to how far from the Moon is the Moon's exosphere gravitationally bound to it? For the Earth's exosphere it is 120,000 mi (190,000 km) or half the Moon's distance from the Earth, beyond that the ...
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List of J₂ values for solar system bodies beyond the planets; are there any prolates?

J₂ values for the planets can be found in several sources including each planet's planetary fact sheet. Without looking I'm going to assume they are all positive (oblate) because each planet rotates ...
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Why do Venus, Earth, and Mars have tall volcanoes, but the Moon, Mercury, and Io don't?

There are numerous examples of multi-kilometre tall mountains such as Maat mons on Venus, Mauna Kea on Earth, the Tharsis volcanoes on Mars. We don't find similar such examples of volcanic edifices ...
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How does the Hubble Space Telescope measure the speed of the wind inside Jupiter's Great Red Spot?

Space.com's Jupiter's winds of change show increased storm speeds in Great Red Spot and Hubblesite.org's Hubble Shows Winds in Jupiter's Great Red Spot are Speeding Up both link to the recent open ...
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What is k2, how does it relate to Io's volcanism and how can Juno constrain its value?

This answer to Does Juno's UVS have any chance to spot Europa plumes? links to Juno OPAG REPORT by Scott Bolton, OPAG, September 2020. The slides detail past and future Juno flybys of Jupiter and some ...
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Are there any SuperCam spectra available?

A lot of pictures from the SuperCam, the NavCam or the Mastcam onboard the Perseverance rover are available online (for instance on the NASA and JPL websites). Have any SuperCam spectra been made ...
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What's the expected distribution of planet masses in a given system?

Given that the mass of a planet at a given orbital distance r is dependent on the protoplanetary material in the neighborhood of r at the time of formation (assuming no planetary migration), what ...
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...but where did Mars' atmosphere actually GO?

In this answer to How is space a vacuum when there are planets, gases, etc? I mention that most of Mars' original atmosphere was swept away by the solar wind after the planet lost its magnetic field ...
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Whether the comet is moving in an elliptical or hyperbolic orbit around the sun?

The time of observation after the first observation (in years), the distance between the earth and the comet (in AU) and the angle between the sun and the comet (in radians) is given. How to find ...
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What discoveries were made thanks to Pioneer orbiter data?

Based on the Wikipedia page Pioneer Venus Orbiter (also known as Pioneer Venus 1, Pioneer 12, 1978-051A) there were quite a few scientific instruments on board. But what scientific results were ...
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Can we learn anything from the chaotic movement of Hydra and Nix?

The NASA Visualization Explorer Moons In Chaos says Hydra and Nix, two of the moons of Pluto, show chaotic movement due to the shifting gravitational field. How long a day lasts and where the sun ...
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I have a question about the wording in a paper about a planetary system and comets

I was reading a paper. This is the paper: https://arxiv.org/abs/2006.01711 (https://ui.adsabs.harvard.edu/abs/2020MNRAS.496.4979D/abstract In the method section in the second paragraph there is a bit ...
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How massive does a moon have to be to have a stable magnetic field?

Is there a minimum mass or other minimum properties necessary for a body to have a strong, stable dynamo to create a magnetic field conducive for life? For example, would it be possible for Titan to ...
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Has lunar opposition surge ever been observed from Earth? From Earth orbit?

This thorough answer to How long does lunar opposition surge last? Are there measurements of the full Moon getting suddenly brighter? details observations of lunar opposition surge by the Clementine ...
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How long does lunar opposition surge last? Are there measurements of the full Moon getting suddenly brighter?

Wikipedia's opposition surge is a short article and forwards shadow hiding and coherent backscattering as proposed mechanisms, but it doesn't really explain how much the brightness of the Moon ...
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How do they know the TNT equivalent of the meteor explosion over Vermont?

I've seen several reports of this meteor explosion, below are two. Was there infrasound recordings of the pressure wave, or were weak, local seismic signals recorded, or it this just a ballpark ...
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What is the underlying nature of the dark spot found on Uranus?

What is the nature of bright spots found on Uranus? actually quotes Space.com's Uranus Has a Dark Spot which says: During the past decade, many bright spots have been seen on Uranus in both red and ...
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What will a future cold and "dead" Jupiter look like? [duplicate]

I heard Jupiter is dying like getting smaller. For example, from Guillot et al. 2004 3: The Interior of Jupiter (also here): (Jupiter)... is still contracting at the rate of ~3 cm per year while its ...
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How do pressure, temperature, and gravity affect a smaller body than Earth with the same bulk composition?

Earth has a density of about ${\rm 5.513 ~g/cm^3}$ with one Earth radius and one $g$. Venus, a very similar planet to Earth and likely with about the same bulk composition, has a density of about ${\...
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Do moons of rocky oblate planets migrate to low inclination over time? If so, does the time it takes depend on the Moon's size?

Discussions elsewhere suggest that this happens and that smaller moons would tend to low inclination with respect to the planet's equator faster than larger ones. For example, Mars' small moons are ...
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Do some comets spin? If so, how fast?

The GIF below is copied from my question earlier What might a CN filter be in the context of comet watching? Is it showing dust, or gas, or something else? where I'd said: In this post on the website ...
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1answer
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Are ocean water planets at Mars' atmospheric pressure possible?

Can water planets exist whose atmospheric pressure at sea level is just above the triple point of water, say at about 690 Pa (0.1 psi)? If no, why not? Just curious. How thick or thin can atmospheres ...
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Gravity on Mercury's highest elevation?

This post answers what is Mars' gravity at its highest point (Olympus Mons) compared to the Earth's and Mars' standard, it's 0.3736 g (Mars standard is 0.3794 g). This also seems to be the lowest ...
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Caves traced in nine planets of solar system

Are there chances of caves being found or traced on other planets of the solar system? What's the solution? Manufacturing special telescopes for viewing or observing caves on other planets? or ...
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Qualities of gas giant atmospheres at a density of 1 gram per cubic centimeter

At what depth in the atmospheres of the gas giants does the density of their atmospheres equal 1 gram per cubic centimeter? What is the pressure and temperature at these depths? Are the radiations ...
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Could rocks from Earth have reached the Kuiper belt, or Neptune at least? If so, how?

This answer (currently edit 3) to How certain are we that we have not sent life to other planets/moons? begins: First of all, rocks from Earth are probably just about everywhere in the Solar System. ...
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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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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 fast is Neptune getting brighter? When was was this first noticed and reported?

This answer to Compute Planet's Apparent Visual Magnitude reports the new work on planetary magnitudes, and contains an intriguing blurb about Neptune: Neptune keeps getting brighter. No one knows ...
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Why is there so little nitrogen in the Martian and Venusian atmospheres?

Why don't our neighbors have much nitrogen? You would think that, without 'nitrogen-fixing' organisms and such, there might be more.....
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Can tidally locked planets have liquid oceans on their night side, and would such a planet be habitable?

Let's say we have a tidally locked planet orbiting a star. And let's say that the conditions on its surface are just right for water to exist on its surface. Conventional wisdom says that the water on ...
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Magneto tail effect on the other planet in a binary planet system

Let's say there are 2 earth sized planets orbiting each other around 750,000km apart and at a distance of roughly 1.2 AU from a sunlike star with a mass of 1.105 solar masses. Since they are binary, ...
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Binary planet orbital distance

From reading various sources online, I see that some people talk about binary planets in very tight orbits (around 1 or 2 planet radii). I am wondering if it is possible for a binary planet (Double ...
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Do gas giants have a core?

I have always wondered how Jupiter and the other gas giants worked when it came to having a core(If they have one). Would it be rocky or liquid, or can it be a gas. Every time I have asked this ...
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When could the Roche limit be larger than the Hill sphere?

This answer to Are Saturn's rings stable? begins with: Most of Saturn's rings are inside it's Roche limit, which means they will never clump together. Tidal forces prevent this from happening. I ...
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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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Does Earth's magnetic field become stronger when a solar flare hits?

This curiosity arises as follows: when ejecta from a strong solar flare hits Earth, will the Earth somehow counter its impact with a stronger magnetic field. Or, earth's magnetic field as limited ...
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Is there a way to tell the difference between earth andesite from Mars

I'm curios if there is a way to test if this sample might be Martian andesite. What type of oxygen isotope (or other) test can be done to address this in some way? As background, any information ...
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How much damage would collision with a similar mass primordial black hole do to earth?

All this talk of Planet 9 perhaps being a primordial black hole (PBH) made me wonder how dangerous a PBH collision with earth would really be. Specifically, if earth collided with a PBH of 1 earth ...
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Why would a tidally-locked rocky planet have a first-order spherical harmonic surface temperature distribution?

The new Letter to Nature Absence of a thick atmosphere on the terrestrial exoplanet LHS 3844b (also ArXiv) analyzes the thermal infrared light curve from the system (about 4.5 to 5.5 um). The planet ...
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Why is Saturn invisible in this radar image of its rings?

The image below is from Radar imaging of Saturn’s rings Nicholson, P. D. et al., Icarus 177 (2005) 32–62, doi:10.1016/j.icarus.2005.03.023 and discussed further in this answer to How did Arecibo ...
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Neptune's Internal Heat Source

Unlike its sister planet Uranus,Neptune has a substantial internal heat source which gives rise to a dynamic atmosphere & weather. Wikipedia says: As with Uranus, the source of this heating ...
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Is the boulder on the peak of Tycho Crater the core of the impactor, or is it a random rock?

There's a strikingly visible boulder sitting right at the top of the peak complex in the center of Tycho Crater on the Moon. Is it just a coincidence that this gigantic, bright rock is sitting dead ...
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Is it plausible for a planet that is positioned in the habitable area of a solar system to have little extractable metals?

I am big fan of Asimov's Foundation and I am wondering about the plausibility of some of Foundation's imagined words. According to this article Terminus was a special world with little metals: It ...
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Does Mars' "Northern ocean" have another name? What about the "Inland Sea"?

The March 15, 2019 Phys.org article A NASA spacecraft may have explored the edges of an early Mars sea in 1997 shows a stylized map of an area on Mars where the Mars Pathfinder landed and uses colors ...