Questions tagged [planet]

Questions on astronomical objects orbiting a star massive enough to be rounded, not massive enough to cause fusion, and which have cleared its orbit of planetesimals.

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6
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1answer
65 views

How could a captured asteroid enter a circularized orbit?

Ok, the simple answer would be through gravity assists from moons, taking a ballistic capture orbit into a circular orbit. I am wondering the chances of a ballistic orbit becoming a stable (on the ...
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2answers
840 views

Is it possible for a planet to heat up its moon to habitable temperatures solely through infrared radiation?

Stars are powered by nuclear fusion and the energy released radiates through their surface as heat. But all objects radiate away some form of electromagnetic radiation depending on their temperature. ...
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Frequency of planet masses in any given star system?

This question is a follow-up to the expected distribution of planet masses in a given system. I am wondering, what is the distribution of various planet masses in any given system? I am expecting a ...
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1answer
80 views

Why is planet visible very good in a specific time of the year?

I'm trying to solve this task: Why do periods of good evening visibility of the planets usually come in winter and spring, and morning ones - in summer and autumn? Could somebody please explain what ...
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1answer
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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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1answer
68 views

Is life possible on other celestial objects (apart from planets) even theoretically? [closed]

For example, asteroids, comets, stars, heliosphere etc?
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1answer
62 views

Where can I find planetary rotational axis direction?

I can find axial tilt of planets easily, but that doesn't specify the direction of that tilt, i.e. planet's rotation axis may be anywhere in circle defined on a sphere by axial tilt value. And I can't ...
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1answer
144 views

Not getting quality images in telescope

New to astronomy, I have a Newtonian telescope (Celestron 130 eq) with 5.2 inch (~132 mm) aperture with 650 mm focal length, Spherical mirror. And having 4mm, 10mm, 12.5mm, 20mm,20mm (erecting ...
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Precision of orbital period of exoplanets vs solar system planets (Extrasolar Planets Encyclopedia)

I noticed that the Extrasolar Planets Encyclopedia lists the orbital period of L 98-59 b in days to 7 decimal places. Can astronomers really measure orbital period of exoplanets to greater precision ...
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2answers
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How slow would you age on a double gravity planet?

How slow would you age on a double gravity planet? Gravity of the planet A is 10 units. If you are taken from planet A to planet B where gravity is double that of A, i.e. 20 units. How slowly would ...
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Would Atlas Pro's prediction about the color of plant in Kepler-186F work as a biosignature to search for life?

The Atlas Pro video that prompted this question is this. Tl;dr: it is argued that due to the different spectrum of radiation emitted by Kepler-186 and what is known about the evolution of ...
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2answers
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What is the probability of life having developed or going to develop in our solar system another time?

I'm sorry I am not quite sure this question satisfies this point: Questions that are purely hypothetical, for example a question such as 'Could a black hole destroy the universe' or 'What if our ...
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What is the size of the universe? [duplicate]

Will as a result of the continuation of technological progress in the twenty-first century more perfect telescopes or other astronomical instruments that will allow to know what is on the surface of ...
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1answer
57 views

Special case of rotation period

Rotation period is either prograde, like the Earth, or retrograde, like Venus. How likely is it for a body orbiting its parent object (either a planet around a star or a moon around a planet) to have ...
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1answer
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Can the pebbles growth model be applied to the rotations of planetary systems? [duplicate]

I've just read the University of Amsterdam 2019 News item Pebbles determine the direction in which planets rotate (which links to R.G.Visser et al (2020) Spinning up planetary bodies by pebble ...
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2answers
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Moons with synchronous rotation in our solar system

Are all moons in our solar system rotating synchronously around their planet? If not, what are the criteria that some do and some don't? Many thanks for any insights!
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1answer
337 views

At high temperatures, do planets glow like blackbodies?

I've been messing around in Universe Sandbox for a while and noticed that as a planet heats up, it glows like a blackbody starting at ~4000 K. Is the simulation here accurate, or do very hot planets ...
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Longest and Shortest day of the year in all planets

Can we trace the longest and shortest day of the year in other planets of Solar system similar to earth planet i.e. Mars, Saturn, Venus, Jupiter, Mercury, Neptune, Uranus?
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Will a solidifying core inside a planet affect its appearance?

In this question it is said that Mars once had a liquid core that solidified. If the liquid has a smaller density than the solid, will this affect the outer parts of the planets? For example, if the ...
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60 views

What would be the electric potential and the energy produced in a cable connecting two electronic devices on the magnetic poles of the earth? [closed]

The earth is a large magnet moving in the magnetic field of another large magnet the sun. And if we connect the two poles of the earth by a cable there would be energy and an electric potential in ...
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1answer
60 views

Does the sun have a notable frame-dragging effect on the planets?

Frame-dragging is a general relativistic effect that can be imagined as the effect that the momentum of mass-energy has (the stress elements in the stress-energy tensor) on mass-energy in the ...
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1answer
61 views

What does it mean for a planet to have an "icy" core?

My understanding of the physics of planets leans heavily on my understanding of the physics of stars - of course there are important differences. One important difference that I've found is the nature ...
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1answer
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Is this how stars’ right ascensions correlate to planets’ longitudes on a 2d map?

This is my first ever online question, so please bear with me: I’m working on an A1-sized map of at least 100 of the largest solar system bodies (henceforth just called ‘planets’, ignorning the IAU ...
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1answer
57 views

Weight of a gas measured in Space and other planets of Solar System

I searched for how measure gas weight and about gases in space https://www.shutterstock.com/search/space+gases https://education.seattlepi.com/gases-found-outer-space-5888.html Will the weight of gas ...
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48 views

How likely are triple planet systems?

Is it likely to ever discover three planets of similar mass revolving around a common barycenter, or would such a system be too unstable? Such triple planet system would look like a triangle once in a ...
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How to distinguish primary hosts (stars) and orbiting satellites (planets) and tertiary bodies (moons) by their mass and trajectory?

Suppose one has run a gravitational simulation of N bodies (has the mass, vector positions, vector velocities, etc for each body), but knows nothing a priori about ...
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2answers
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How close to a host star can a tidally locked planet be and its dark side still maintain a moderate temperature?

So, imagine an atmosphere-less planet, tidally locked to a sun-like star. How close to the star can the planet be before its dark side becomes too hot? I imagine that at some point the rocks on its ...
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Calculating the radial tidal amplitude on a planet from the fluid Love numbers

How do you calculate tidal amplitudes from the fluid Love numbers? In my course on planetary physics I saw an approximate expression for the displacement from equilibrium tide: $$\Big|\frac{V_T}{g}\...
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Converting Invariable plane to J2000 ecliptic

I've been following the answer given by Mike G here: How to calculate the orientation of planets at current epoch to get planets to have the correct orientation in my program, but all the angles are ...
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1answer
106 views

Maximum and minimum masses and sizes of giant planets?

What are the minimum & maximum masses and diameters of giant planets? Minimum end of the scale Earth has mass of 1 Earth mass and a mean radius of 6,371.0 kilometers, and thus a mean diameter of ...
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What is the theoretical maximum variability a pulsating red giant can have such that a habitable planet can stay habitable for long periods of time?

I was reading about red giants and came across this statement: Some research suggests that, during the evolution of a 1 M☉ star along the red-giant branch, it could harbor a habitable zone for ...
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1answer
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What is the Milne-Eddington Approximation?

In this paper: Planet temperatures with surface cooling parameterized it states in the "radiation model" the following: The Eddington–Milne approximation relates $T_0$ and $T_e$ through the ...
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1answer
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Questions on apparent motion of superior planets

Question Why is it that superior planets seem to oscillate up and down of the ecliptic, from the view of an observer on Earth, with a period equal to the planet's orbital period? Additionally, why do ...
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1answer
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What is the longitude of the winter solstice for the various planets?

I am looking for data showing the longitude at which the various planets in the solar system reach their winter solstice. Where could I find this data?
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1answer
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Assuming a hypothetical system without gas but only solid rocks, how big of a planet can form through the coalescing of these rocks?

I have heard that gas giants are primarily huge solid bodies like regular rocky planets that exponentially gained more and more gas in their atmosphere through their increase in mass which they use ...
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1answer
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How to measure mass of planets' core from orbit

I am told in an astrophysics lecture the following. The mass of Saturn's core was measured by Cassini when it completed its final flyby between the rings and the planet itself. It was also found that ...
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1answer
150 views

Why don't we detect planets around OB stars and no terrestrial planets around A or early F stars?

Looking at an exoplanet database, I noticed that there are very few planets detected around main-sequence OBA stars, and most of them are gas giants/brown dwarfs. Why can't we detect low-mass planets ...
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0answers
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Regarding core fragmentation of a gas giant in the envelope of a red giant

We know that large gas giants, such as Jupiter, have degenerate cores. Let's say there is a hot Jupiter ($5M_J$) that orbits an F-type star. When the star expands into a red giant, the hot Jupiter's ...
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4answers
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Could an orphan/rogue planet have a moon?

Is there some reason why an orphan or rogue planet wouldn't have a moon? Let's say it started out in a normal system and then just got flung out by an unstable orbit.
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What makes a star? [closed]

What are the properties of a star? How do astronomers classify the properties of stars?
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1answer
162 views

Why does Wikipedia state that the Solar System has one unconfirmed planet?

I was looking at exoplanets on Wikipedia, and found this surprising information: The table states that the Sun has 8 planets (obviously) and one unconfirmed planet. Why is this here? I think it's ...
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0answers
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Why do degenerate objects get hotter as more mass is added?

After reading this question, I decided to post a question about degeneracy. I've seen simulations on large, $15\text{+ }M_J$ objects that are accreting mass. They do not grow in radius, instead they ...
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1answer
121 views

Synodic Day and Sidereal Day

If given the sidereal day, is it possible to derive the synodic day of Earth? If a derivation is possible, could anyone illustrate it or point me in the right direction? Wikipedia's Synodic day begins:...
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1answer
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Fate of a planet orbiting a Lagrange point behind a star?

Let's say there is a planet orbiting at L5 behind a star, which is in turn orbiting a more massive star, like so: What is the ultimate fate of this planet? I'm predicting that it will spiral into the ...
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1answer
273 views

Can a habitable planet be smaller than 0.58 Earth radii?

According to the below image, the lowest escape velocity a planet can have in order to still be able to retain water on its surface and have a temperature above freezing is 6.5 km/s minimum. With ...
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North Stars of each Solar system planet?

What are the North Stars of each individual body points too? E.g. Earth points to Polaris. Mars points to Deneb/Alpha Cygni. What about Sun, Mercury, Venus, Moon, Jupiter, Saturn, Uranus, Neptune, ...
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How big can an object get before its core becomes degenerate?

I am wondering, what is the most massive object we know of that does not have a degenerate core, and what is the least massive object that does have a degenerate code? We know that Jupiter has a core ...
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1answer
78 views

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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1answer
33 views

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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1answer
58 views

If a Jupiter-sized sphere of a translucent liquid were to suddenly appear, what would the inner core consist of? Would the planet refract light?

Assuming Jupiter is suddenly replaced, or if a giant sphere of fruit juice or other translucent mixtures/liquids were to appear bearing a similar radius to that of Jupiter, hypothetically , what would ...

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