Skip to main content

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.

67 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
8 votes
1 answer
620 views

Why do the Sun and gas planets rotate faster at equator than at poles?

From this site, it states that: The Sun spins faster at its equator than at its poles. I have also read somewhere that the gas giants (gaseous planets like Jupiter, Saturn, Uranus, and Neptune) also ...
apk's user avatar
  • 949
6 votes
0 answers
153 views

How was the axial tilt of planets measured?

https://en.wikipedia.org/wiki/Axial_tilt#Solar_System_bodies gives the axial tilt of all planets with two decimal precision, but how and when were they measured so precisely ? I guess it's "easy&...
Dr. Goulu's user avatar
  • 161
6 votes
0 answers
173 views

How quickly do planetary rings form?

Just a very general question, but I haven't seen this discussed elsewhere. If a moon gets busted up for some reason, say a collision with another moon, and is at the right orbital distance from its ...
Generality's user avatar
6 votes
0 answers
219 views

Kepler - Creating the Ellipse (Astronomia Nova)

In Chapter 58 in Astronomia Nova, Kepler made his final step to finally create the ellipse (for the orbit of planets) http://science.larouchepac.com/kepler/newastronomy/part4/58/index.html In the ...
user15474's user avatar
  • 159
5 votes
0 answers
88 views

Is there a noob-friendly website/app for tracking a astronomical body's apparent movement over time?

As I walk home along my road most nights in winter, I see the Moon and one-or-more planets. Unsurprisingly, over the last 2 months, if it's been the same planet and it (and the Moon) has been in ...
Brondahl's user avatar
  • 338
5 votes
0 answers
289 views

Why aren't there sulfuric acid seas on Venus?

It's commonly known that sulfuric acid rain doesn't reach Venus' surface. It evaporates instead because the surface it too hot. But considering how high the pressure at the surface (9.3 MPa), shouldn'...
Prido1024's user avatar
5 votes
0 answers
98 views

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 ...
slowerthanstopped's user avatar
5 votes
0 answers
82 views

Can mean motion resonances make orbits more unstable rather than more stable?

This paper on closely packed orbit simulation seems to suggest that having the planets in first and second order resonances decreases the time till orbits cross each other. I'd got the impression that ...
Axion's user avatar
  • 345
4 votes
0 answers
202 views

Help identifying a very slow-moving object during meteor shower photography

I just wonder if anyone could shed any light on this puzzle. Two nights ago whilst I was out photographing the Lyrids meteor shower from the UK something else showed up on my images when I checked ...
Harvey Shelley's user avatar
4 votes
1 answer
167 views

Is it possible to have a positive rational number of months (more than 1) in a year?

It is possible for a planet to have orbital resonance with a sun (e.g. Mercury has a 3:2 spin resonance with the sun). It is also possible for a moon to have orbital resonance with a planet (e.g. our ...
Daniel-耶稣活着's user avatar
3 votes
1 answer
99 views

Easy guideline for using JPL Horizons DE431 for planets in aphelion and perihelion from 11000 BC to 16000 AD?

Can someone give me a step by step Guide how to use JPL DE431 or DE441 as a Beginner. I tried the Horizons website app and Webgeocalc but it didn't showed understandable Information. This websites ...
Patrick Wackenhut's user avatar
3 votes
0 answers
172 views

How can Jupiter rotate faster at the equator than at the poles (in degrees per second)?

Jupiter rotates slightly faster at the equator. If inertia is conserved as average angular momentum, what is the physical mechanism that creates a gas which is ~1% faster angular momentum at the ...
Wolfgang Weber's user avatar
3 votes
0 answers
74 views

How long would it take for a planet captured by a red dwarf to become tidally-locked if it started out rotating retrograde?

So say for the sake of argument that we have a red dwarf orbiting a G of K-class star. An Earth-sized planet forms, maybe at one of the dwarf star's Lagrange points to its primary, and eventually ...
PrincipledStarfish's user avatar
3 votes
0 answers
61 views

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 ...
sno's user avatar
  • 1,464
3 votes
0 answers
53 views

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 ...
zeebeel's user avatar
  • 31
3 votes
0 answers
45 views

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 ...
WarpPrime's user avatar
  • 6,684
3 votes
0 answers
83 views

New method for exoplanet detection based on iridescence?

Could it be possible to detect exoplanets that have an abundance of iridescent minerals by analyzing their star's spectra over time as the angle in observation would lead to changes in absorbed ...
Florian Lienert's user avatar
3 votes
0 answers
58 views

Simulating oceans and ice sheets on other planets or moons?

From my friends in geosciences I learned a lot about General Circulation Models (GCMs) (for Earth's atmosphere and oceans). I also learned about ice sheet models for floating ice (like sea ice or ...
B--rian's user avatar
  • 5,636
3 votes
0 answers
115 views

Average effect of a planet on a comet

I'm considering a problem involving star S, planet A, and a comet B. The orbits of the planet and comet are eccentric, with eccentricities $e_A$ and $e_B$. I'm trying to calculate the average change ...
Allen O'Hara's user avatar
3 votes
0 answers
171 views

Intrasolar planetary surface temperature change divergence from Earth

Considering the vast amount of insulating gas emitted by human activity on Earth without a coincident release on all other planets in the solar system as well as the phenomenon that planets in a solar ...
user avatar
3 votes
1 answer
140 views

What would Uranus look like from light years away?

It has been suggested that at least some of the "super-puff" planets may actually be ordinary planets with rings. Saturn, for instance, may appear as a "super-puff" to an alien ...
Joe Peters's user avatar
2 votes
0 answers
31 views

How to get the direction of the rotation axis of a celestial body using JPL Horizons?

When asking Horizons for ephemeris, it doesn't include the information of the rotation axis. Is there a way to obtain it?(may include calculations based on the given information) And is there any way ...
Stellar Horizon's user avatar
2 votes
0 answers
82 views

How can I calculate current position of planet in sky

How can I calculate current position of planet in sky from earth's point of view. I want to calculate based on given DATETIME and Location For example, if I see current position of planets on "23 ...
Mangesh Sathe's user avatar
2 votes
0 answers
108 views

True node (NN) calculation .. off by 10 seconds

...
dimitri33's user avatar
  • 167
2 votes
0 answers
67 views

If a planet orbits an M-Star in an S-type orbit around a G star, what is the minimum distance from the G star that it could remain tidally locked?

I'm wondering how close a planet-M-dwarf system could orbit a G star and have the planet remain tidally locked to the M star. I'm curious, because I'm designing a habitable planet, and I want the ...
Elhammo's user avatar
  • 1,107
2 votes
0 answers
58 views

Why are triple conjunctions in a resonance forbidden?

I was reading the Wikipedia article about orbital resonance and noticed that Laplace resonances forbid triple conjunctions. This seems to be supported by the Io-Europa-Ganymede system and the Nyx-Styx-...
WarpPrime's user avatar
  • 6,684
2 votes
0 answers
43 views

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 ...
WarpPrime's user avatar
  • 6,684
2 votes
0 answers
60 views

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 ...
Rubén Crespo's user avatar
2 votes
0 answers
60 views

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 ...
slowerthanstopped's user avatar
2 votes
0 answers
166 views

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 ...
WarpPrime's user avatar
  • 6,684
2 votes
0 answers
76 views

Abundance of penitente ice formations in the solar system

When researching for my question on extraterresitral snow, I learned about a rare snow formation called penitente which seems to be found on various (dwarf) planets, like Earth, Mars, and Pluto. ...
B--rian's user avatar
  • 5,636
2 votes
0 answers
1k views

How to find the temperature of a planet accounting for the atmosphere?

Recently, I started writing a program to generate star systems, and I need a formula to find the approximate surface temperature of a planet. I know of several formulas for this, for example this one ...
Nirvana's user avatar
  • 251
2 votes
0 answers
96 views

Software apps for calculating distances between planets

Are there somewhere any software apps for calculating distances between any planets in our solar system?
Anton Cristian's user avatar
2 votes
0 answers
61 views

Do retrograde spin-orbit resonances exist?

The end state of rotation of an initially fast-spinning prograde terrestrial planet (in the absence of additional forcings such as "thermal tides" in an atmosphere, e.g. Venus) is a spin-...
user avatar
2 votes
0 answers
894 views

Identify moving object in the sky at night?

Last night in the Carribean, I was looking at the sky at about 8PM EST, and I noticed this really tiny object moving pretty fast from left to right, just between the two stars in the photo. It's very ...
rbhat's user avatar
  • 401
2 votes
0 answers
2k views

Calculating the position angle of the moon (the rolling back and forth)

I have been watching the the NASA Moon Phases Video of the year 2020. Pretty much everything makes sense and I know how to calculate it including the moon phases, declination, azimuth, apogee and ...
The Oathman's user avatar
2 votes
0 answers
61 views

What is the radial dependence of the density of Jupiter or Saturn?

Can anyone point me to the reference where I can find the density of Jupiter or Saturn as a function of the distance from its center?
Youngsub Yoon's user avatar
2 votes
0 answers
55 views

Frequency of Earth type cores?

I've read many interesting threads concerning the composition of different planet cores in the solar system while trying to see if this question has already been asked. It appears as if Earth is ...
user1583807's user avatar
2 votes
0 answers
218 views

Why does the axial tilt & the rotation speed of Saturn & Jupiter vary so much?

I have seen Jupiter and its 4 largest moons in a telescope, several times. The moons are always aligned in a line. This is fine. Very interesting. But.. in case of Saturn, not only that we can see its ...
Petr Hykš's user avatar
2 votes
0 answers
797 views

How to calculate the orbits of Neptune and Pluto based on the orbits of Uranus and Neptune respectively?

I get the below from Neptune and Pluto. In 1821, Alexis Bouvard published astronomical tables of the orbit of Neptune's neighbour Uranus.[22] Subsequent observations revealed substantial deviations ...
questionhang's user avatar
  • 3,137
2 votes
0 answers
211 views

The path of the planets on the celestial sphere

I know that planets have a "wandering" movement on the celestial sphere. I also know that their period around the Sun vary largely as compared with the period of the Earth (one sidereal year), ...
João Pimentel Ferreira's user avatar
2 votes
0 answers
40 views

When does oscillation of interplanetary plasma occurs?

When does oscillation of interplanetary plasma occur? When and what are the reasons of the excitation of this plasma that makes it oscillate? Does it oscillate when is not excited? Can extremely ...
Noduagg's user avatar
  • 63
2 votes
0 answers
95 views

How much heat emanates from the planets after formation?

The 2nd answer to this question by MBR got me thinking about this. Is there some general guideline for residual heat a planet should emit, say 4.5 billion years after formation. I'm defining heat ...
userLTK's user avatar
  • 24.1k
1 vote
0 answers
73 views

How can I calculate the geocentric longitude of Pluto in a similar way to VSOP87's algorithm?

The book "Astronomical Algorithms" teaches a way to calculate the position of any of the planets for almost any date, until you get to Pluto. To try to get around that, I attempted to ...
Matheus Azevedo's user avatar
1 vote
0 answers
45 views

Timelapse Video Of Motion of Mars?

I'm trying to find a timelapse video of mars moving against a fixed background of stars - could someone point me in the right direction? Thank you!
Stephen W.'s user avatar
1 vote
0 answers
127 views

The rocky planet sizes between the Sun and Jupiter are small, big, bigger, small, and unfinished. Is there a reason?

The rocky planet sizes between the Sun and Jupiter are small (Mercury), big (Venus), bigger (Earth), small (Mars), and unfinished (the asteroid belt). Is this just random chance or is there a theory ...
phil1008's user avatar
  • 119
1 vote
0 answers
34 views

On the relationship between semi-major axis and the Longitude of the Ascending Node

I noticed something looking at the Longitude of the Ascending node of various planets. Mercury: 48.331° Venus: 76.680° Mars: 49.57854° Jupiter 100.464° Saturn: 113.665° Uranus: 74.006° Neptune: 131....
DanceroftheStars's user avatar
1 vote
0 answers
88 views

What would happen if a low-mass primordial black hole was captured by a brown dwarf or planet mass object?

Prompted by a recent PBS SpaceTime video The video in question discusses what would happen if a low-mass (asteroid-mass) primordial black hole were captured in the core of a Sun-like star (a so-called ...
asgallant's user avatar
  • 571
1 vote
0 answers
76 views

What do chthonian planets look like?

Obviously, a chthonian is going to be hot, but what colours could it have? What would the surface composition be? Would it keep patterns from the gas-bands it used to have, or would those have been ...
Kazon's user avatar
  • 587
1 vote
0 answers
61 views

What is the minimum strength of a magnetosphere needed to sustain life?

On Earth, the magnetic field intensity is roughly between 25,000 - 65,000 nT. Assume for a second that we have a planet with double the atmospheric thickness of Earth but with a similar composition. ...
ΓΙΑΝΝΗΣ ΜΙΧΑΗΛΙΔΗΣ's user avatar