Planet Definition and 821 Threads

So I remembered that Jupiter shares his orbit with two asteroid groups (Jupiter trojans) at Lagrange points in its orbit. So I want to ask, is it at all possible for planets or planetoids to be formed at Lagrange points in a star system, or will gravitational interference always ensure that it...

I am an author/novelist and I'm working on a huge science/fantasy project that's been in development for the past 5 years, and as a science fiction fan I've always hated when people get the science really wrong. So my question is: how would the gravity of another planet influence human...

I figured this would be a problem in some classical mechanics book but so far I can't find an answer anywhere. Assume there is no drag or lift, and since the planet is not rotating we don't have to worry about Coriolis effects. I'm working on a solution but I want to see if my work is correct...

I want to write a story about a planet that has yearlong eclipse that how its natives and ecology adapt to this celestial condition. I am just wondering how realistic/feasible it is for some planet to have a moon in stable orbit producing eclipse for 1-3 years, every 70-100 years.

What is the difference between a rocky planet's core and the core of the sun?

From the previous question I got the star is giving off around 4.01*10^27 W. I am unsure how to find the answer it asks for. Please help.

Well... that: Please, could you please assist me in obtaining a rough estimate of the distance from the Sun at which a planet resembling Venus or a hypothetical Venus-like planet (for the sake of simplicity) would have a habitable-zone surface temperature? A "back-of-the-envelope" educated...

HI! I tried to solve this exercise, by assuming that it is an inelastic collision, the planet is spherical, and that the rotation axis is parallel to the z-axis, see the figure attached. (1) before the collision, (2) after the collision.I started by assuming angular momentum conservation, which...

TL;DR Summary: Solar sytem forces on Unity Hello ! For my last year in my school, I've got a project to do, and I wanted to recreate the Solar system with forces on Unity. My forces are Velocity and Acceleration (I'm using the Frenet's formulas). I'm sorry I'm not a physicist and that's why...

Consider a ship with a propeller. A propeller has to be perpendicular to the way you want the ship to move. It has to be perpendicular to the forward direction. In 3D that means that the propeller rotates in the right-up plane. In 4D we have other choices. The ana-right plane is also...

A 4D planet has no axis of rotation. Nothing special about planets, all freely rotating 4D bodies have two perpendicular planes of rigid rotation. (Clifford proved this in the 19th century.) Now there is nothing stopping us from thinking of planes of rotation here in 3D Universe. It's the...

On a planet with four spatial dimensions and one of time a clock would look like this. The hands are connected with pivots. The height of the jewel corresponds to the height of the Sun in the sky. If it is above white then it is daylight, if above black it is night. Here the sun has height...

Example: The radius of the Earth is 6371 km. It has an average density of 5.5 g/cm3. Earth's inner core has the highest density at 12.9 g/cm3 [more than double the average]. Its surface gravity is measured in units of acceleration, which, in the SI system, are meters per second squared. It may...

This is both a biomechanical and sociological question. There is a planet. It orbits around a large star whose goldilocks zone is significantly far from the star that the orbit is measured in thousands of Earth-years1. The planet is tide-locked2. The planet is otherwise the same size and...

Jupiter is huge. TrES-4 is 1.8 times the size. How big can planets actually get? is there a limiting factor? cheers.

So the theory is the center of a "black hole" is nothing more than a planetoid of incredibly dense material, and the black hole is just this planet's atmosphere for lack of a better description. Thoughts?

I've tried to make a "naive" implementation of a planet orbiting a gravitational point source, in Processing (basically Java). Gravity is a constant, and adds to the planet's velocity inversely proportional to the square of distance. I start the planet off with a tangential velocity. I get an...

As far as I know, if vacuum antigravitates, it makes the light that travels through it redshift, e.g. in a very large empty box with mirror walls, light will just lose energy. I am interested in the reverse effect, if we had a very large box or planet with mirror walls, that is filled with...

So, I think it's possible to place an object in an orbit such that it remains perpetually in the planet's shadow, like in my awesome graphical representation. But is it?

Summary:: Astronauts landing on Mars When will the Crewed space mission for Mars exploration event taking place in future? Do you feel that in case life exists for survival on Mars planet, the future generations may actually visit and stay there for many years? Do you feel there will be a...

1) Considering the forces on one of the moons, I have: ##\frac{GMm}{(10R)^2}+\frac{Gm^2}{(20R)^2}=m\frac{v^2}{10R}\Leftrightarrow v=\sqrt{\frac{G}{10R}(M+\frac{m}{4})}.## 2) Considering the initial situation in which the satellite is at rest on the surface of the planet...

Does anyone know where to find information (or software or calculator) able to show on which days / time (2021) where Mercury (and other planets) are as low/high as possible on the heliocentric latitude For example: like the animation seen in the link below. The problem with this site is that...

Hi everyone. I am new here and have a question that has been bothering me for a few days. Maybe you guys can help me out. Suppose a band gives a 60 minute concert on a planet with extremely strong gravity. This concert is recorded on site on a cassette, which has space for 60 minutes. Then a...

I was working on something where I was trying to imagine an astronaut flying into Jupiter. I convince myself that as the spaceship descends, as it slows down, whether or not the astronaut feels heavier or feels more weightless. I believe the answer is that the astronaut will feel heavier and I...

I am considering writing a story that features aliens indigenous to a planet orbiting a red dwarf star. Even so, because of its proximity to the red dwarf, the planet's surface receives much more radiation than Earth's surface does. What is more, the planet has no moon to stabilize its...

Could the existence of the 9th planet of the solar system is possible under these arguments of existence of it some where in the out scurt of solar system? The evidence for Planet 9 comes from its gravitational pull on other bodies. If the planet exists, its gravity will affect the orbits of...

weight/mass = gravitational field strength. my working is -> weight = 150kgx10m/s² = 1500N mass = 150kg gravitational field strength= 10N/kg. is this correct?

Hello All Is it possible to have a planet completely covered in water, like in the film Waterworld? Is it the ultimate fate of the Earth for all the land to be eroded into the oceans, and all the ice to melt, giving a planet showing no land? best regards ... Stef <minor edit - mentor>

https://www.space.com/ancient-earth-had-thick-toxic-atmosphere-like-venus

I know its something to do with my unit conversions because my answer is the right numbers but too small by a factor of 10000. I convert the radius to meters by multiplying it by 1000. I convert the density to kg/m^3 by dividing it by 10. I find the volume using the equation (4/3)*pi*radius^3...

Hi. I'm a science fiction author whose first novel Hemispheres, published through RockHill Publishing, explored a tidal-locked planet (Gliese 581g) where a group of activists increased its rotation to bring daylight cycles to both hemispheres. Now I'm writing the sequel, and there's ecological...

I am not sure whether this thread will get many responses, nor am I sure that any nurse will ever see it. Maybe @Greg Bernhardt can promote it on facebook. Anyway, I strongly feel the urgent need to acknowledge what they all do for us. I had the chance to closely observe the work nurses have to...

I'm watching the Stanford University Lecture series: Einsten's General Theory of Relativity presented by Leonard Susskind (who incidentally has to be one of the greatest educators I've ever watched). Whilst deriving the basic divergence equations relating acceleration, mass density, and...

Hi, I’m looking for ideas and guidance (maybe even formulas?) on making an on-planet situation match a hypothetical solar system. It’s for a fantasy role-playing, but the sentient species must necessarily care (and believably calculate) aspects about their solar system. (However, because it’s...

I was wathcing a video about radial velocity method for seeking exoplanet(video) and on 3:05 author writes that momentum of a star equal momentum of a planet. Why?

Is it theoretically possible that one day a gravitational wave detector will be developed, that is sensitive enough to detect gravitation at the order of magnitude that an Earth like planet has?

It seems (to me) that if everybody received the same amount of money then the health of the global economy would not be affected. Any other ideas?

Summary:: At what distance from the Sun will the speed of the planet be equal to the average orbital speed? I'm not sure where to place this question, please move it in the right thread. [Mentor Note -- thread moved from the technical forums, so no Homework Template is shown] At what...

My solutions (attempts) : a> w=v/r | r=6.35x10^6m | therefore V=7.04x10^-5 m/s b> speed of rotation is faster at the equator than the pole as w=v/r. As w remains constant, as r increases towards the pole V has to decrease. c> F = W - R d> Stuck here. I presume that I have to use the equation...

Lightning is well known from planets, and to some extent the bigger the planet, the more powerful the lightning. Would it also be possible on brown dwarfs (Y, T, L, M)? What about red dwarfs (M)? Other stars?

It's often said that you don't feel Earth rotation because the gravity acts against the centrifugal force. Of course this is true but also your body is turned around once each 24 hours. So I wonder on a planet which is rotating once each 3 seconds and has same g=9,81: Would you feel the rotation?

It is solid

Summary:: Specifically, how Earth and life on it would have evolved if our planet was twice as massive but with the same composition of building elements? Could humans or sentient, upright walking creatures appear in the evolutionary scale in a twice as strong gravitational field? How that...

https://www.bbc.co.uk/news/science-environment-51828871 "Wasp-76b, as it's known, orbits so close into its host star, its dayside temperatures exceed 2,400C - hot enough to vaporise metals. The planet's nightside, on the other hand, is 1,000 degrees cooler, allowing those metals to condense and...

Main Question or Discussion Point How much radioactive warming would occur in the astronomical body specified below? I want to write a story about a very advanced civilization, not yet of Dyson Sphere capability, able to artificially create large planets up to Saturn's mass, of any...

I am hoping a PF participant can help me understand why the tidal forces cause the NGTS-10b planet to fall towards it's star. I more-or-less understand why our moon's tidal forces on the Earth cause the Earth's rotation period to decrease, and the conservation of angular momentum of the...

The other day my friend asked me a really interesting question regarding the scene from interstellar where they go down to Miller's planet, where every hour on this planet is 7 years of Earth time. He asked me if they were to send a signal to the spaceship where Romilly was, what would happen...

By using the above formula I am getting value of time-period T as 6.757*10^6 hrs. But the answer given is 1.7 - 1.8 hrs.

There are lots of decent articles about this, examples: https://www.space.com/40435-finding-aliens-humanity-reaction.html https://en.wikipedia.org/wiki/Potential_cultural_impact_of_extraterrestrial_contact - in part, discusses how speculative this subject can be Well, since Jenner first...

Hello, and thank you again to anyone who can confirm if I have the right answer or who can give me some suggestions. This question felt like a bit of a surprise because we have not yet covered one where the mass of a planet was missing. Thus, my confidence in my work is low. Part b felt like a...