Planet Definition and 812 Threads

I thought of this 'paradox' which is somewhat similar to the twin paradox but can't be explained by a lack of symmetry etc. It is very similar to many paradoxes I have heard before of which the resolution is known (which is why I am mostly sure this can be resolved) Bob is looking through his...

Homework Statement (a) Prove that the time average of the potential energy of a planet in an elliptical orbit about the sun is -k/a. (b) Calculate the time average of the kinetic energy of the planet. Homework Equations F = \frac {-dV} {dr} = - \frac {k} {r} The Attempt at a Solution [/B]...

I know that it is probably a gas giant, but why blue? Saturn and Jupiter, and even Uranus aren't blue, so why would Planet X be blue?

What is the largest planet (in terms of size) with a hard surface that you can walk on and has a surface gravity close to that of Earth that we have ever discovered? What about the smallest?

Given a planet that rotates at 5000mph And the length of a day being 52 hours how big would this planet be?

Published today in Nature: Anglada-Escudé et al. (2016) A terrestrial planet candidate in a temperate orbit around Proxima Centauri. Nature: 536: 437. doi:10.1038/nature19106 Popular press summary...

I am on Alpha 4 light years away from earth. On 1st Jan, 2016 I lit a powerful laser light towards Earth for 10 seconds and then switched it off. My friend on Earth knows that he has to detect that light after 4 years on the night of 1st Jan, 2020 from a space station using a very powerful...

Thought this might be of interest. diogenesNY ------------- New York Times: Astronomers Discover New Likely Dwarf Planet, the Latest of Many By KENNETH CHANG JULY 13, 2016...

If a planet is in retrograde orbit, what direction would it rotate to also have retrograde rotation?

Hello people, I got a question and please do not understand it as a fake question. In theory would it be possible that when it would come to a collision between the Earth and a big sized asteroid, huge jet engines placed on different places on Earth could bring Earth out of orbit and then...

Homework Statement A satellite is in a circular orbit very close to the surface of a spherical planet. The period of the orbit is 2.53 hours. What is the density of the planet? Assume that the planet has a uniform density. Homework Equations T^2=(4pi^2r^3)/GM V=4/3piR^3 Density= Mass/...

The pinnacle of human civilization is when we can create machines that can destroy an entire planet (by imploding or exploding it). This would extend our control of foreign policy to extrasolar policy in the event life would be detected off world someday. 1. In the movie Ender's Game. The...

I was thinking of having the binary planets in my fictional solar system (Kepler Db(Mars like) and Kepler D#(Venus like)) have a moon. Life is on both of these planets in intelligent humanoid forms, but different from the humanoids on the 2 earth-like planets. For 1 the humanoids on Kepler D#...

Homework Statement Homework Equations The Attempt at a Solution

For the background of one of my alien races, I am having them come from a double-planet. (One roughly Earth-sized, one smaller and tide-locked to each other.) My current issue is to to how far apart to set them to get a reasonable balance between stability (because both planets have developed...

Quick question: what's the calculation required for working out the day length (i.e. rotational period) of a double planet, where both planets are tidelocked to each other? Do just need to make adjustments to Kepler's Third? I've got a spread sheet set up to allow me to calculate orbital...

on earth, we have the poles being very cold and mostly frozen, while the equator is very warm and humid. i would like to know specifically what causes this. i know it is partially because of their exposure to the sun, but i'd like to know some of the details and factors involved. i'd also like...

Let's say there was an extremely long striped bridge between you and the planet. You get a boost towards it causing you to suddenly travel at 0.9C, would you see the horizontal stripes on the bridge get thinner as length gets contracted? Also, the time it takes to travel the contracted length...

I once knew both how atmospheres formed on planets and how oceans of liquid water formed on planets, but I have forgotten that information. I know that both atmospheres and oceans of liquid water formed due to chemical reactions, but I used to know more of the details of what type of matters...

Say you have a binary system (with similar mass) in the following orbit with a planet located at the barycenter, is this possible and is this a dynamically stable system (over billion of years) ?? If this system was an Earth like system would I assume correctly that it would not have a nigh...

Homework Statement Imagine another planet with an acceleration of 10m/s^2 at its equator when ignoring the rotation of the planet. The radius of the planet is 6.2 x 10^6m. An object dropped at the equator yields an acceleration of 9.70m/s^2. Determine the length of one day on this planet...

Hello- I'm looking to entertain an apocalypse scenario in which survivors (this occurs in the future) flee to the dwarf planet Eris. I chose this planet because I love the myth circling it: "Eris was the Greek goddess of discord and strife. It was felt to be a very fitting name for a planet...

How close must a planet be to its parent star in order for it to be tidally locked?

Homework Statement Imagine another planet with an acceleration of 10.00 m/s^2 at its equator when ignoring the rotation of the planet. The radius is 6.2 x10^6 m. An object dropped at the equator yields an acceleration of 9.70 m/s^2. Determine the length of 1 day on this planet. Homework...

Hi there, I was reading up on how planets are classified based on their size, but ran into a problem when I began to consider rogue celestial bodies. If a body has significant enough mass to maintain a hydrostatic equilibrium, yet doesn't orbit a star, I understand that it's classified as a...

Why do we suspect a planet 9 and what are the implications if there is a planet 9? arXiv:1603.07247 [pdf, other] Is there an exoplanet in the Solar System? Alexander J. Mustill, Sean N. Raymond, Melvyn B. Davies Comments: 5 pages + appendix. Submitted to MNRAS Letters Subjects: Earth and...

Homework Statement (Assuming all circular orbits) [/B] Say there is a star with mass M and a planet orbiting that star with a mass m. The star M then suddenly loses half of its mass. (So now it is M/2) What is the new radius of orbit of the planet around the star? Warning: Velocity will not...

A Proton-M rocket carrying the ExoMars 2016 spacecraft blasts off from the launch pad at the Russian-leased Baikonur cosmodrome. Objectives: to search for possible biosignatures of Martian life, past or present. to characterize the water and geochemical distribution as a function of depth in...

Homework Statement How far would be a planet from the earth, when its period would be 2 years? T = 2 years/730 days a = 150*106km Homework Equations a3/T2 = C (C is the Kepler-Constant) The Attempt at a Solution I tried inserting T in days and years, but I always get a wrong solution, since C...

Homework Statement What fraction of its "year" (i.e. the period of its orbit) does a planet spend traversing the half of its orbit closest to the sun? Give the answer in terms of the eccentricity ε of the planet's orbit. This is problem 15 from page 852 of Adam's Calculus 3ed. No detailed...

[Mentor's note: The thread title has been edited to change the level from "A" to the more appropriate "B"] Suppose there is planet Z revolving around black hole. Astronaut from Earth go in that Planet Z and start video recording and make a DVD . Suppose they played that DVD in the computer in...

Hi, as part of my physics assignment, I have the following question: As a spacecraft approaches a planet, the following measurements of velocity and radius were taken. From these values, a graph of v2 (y axis) and 1/r (x axis) was plotted. Use this graph to obtain a value for the mass of the...

Everyone talks about Mars as if it's the only logical choice. What about Mercury? It's about the same distance from Earth as Mars and the timing of the return trip back to Earth would more flexible. I read the high northern latitudes of Mercury have moderate temperatures and are near water...

Is there an accurate method in computing the 'sound' frquency of a planet? For example, taking the orbital path of say Jupiter for one year, and computing it into an audible frequency? I'm looking for ways to compute this, but I am at a loss to where the best starting point is. Could Bohr's or...

Downloads are approaching 300,000 so somebody is interested. The 'planet', if it exists, is expected to have an 'appreciably eccentric' orbit. Is there any inventory of how many teams might be searching for this object?? EVIDENCE FOR A DISTANT GIANT PLANET IN THE SOLAR SYSTEM Konstantin...

If you haven't seen this video before then go watch it :D Question: Answer: It is pretty hard to imagine it as a spring and here is why: 1) At (o) the spring should move by its inertia not by any force. If we look at the planet we can summarize that there are 2 points (As I think) that could...

find new planets by detecting dips in light of stars when planets transits. maybe you will find a cool planet in the process. with data from kepler. heres a link to planet hunters: http://www.planethunters.org/

The proposed orbit of Planet Nine looks like it falls in a gap between the heliopause and the Oort cloud; could planet Nine have caused the gap? Would Planet Nine get most of it's energy (electro-magnetic) from extra solar sources, since it is outside the heliopause?

What would be the propable trajectory and position of the ninth planet that has been suggested few days ago (20.1.2016 by Konstantin Batygin and Michael E. Brown) ? if i understood correctly, the exact position of the planet is unknown and has not been evaluated. But by looking this article...

Homework Statement You are touring a distant planet on which the magnitude of the free-fall acceleration is 65.0 % of what it is on Earth. For a little excitement, you jump off a precipice 500 m above the planet's surface. After 5.00 s of free fall, you ignite the jet-pack on your back...

Hello, I'm new to this forum and, to go right to the point, I created a fictional solar system for a tabletop RPG, appointing some characteristics that I want it to have, but I can't handle the physics to bring up the numbers - so I came here. To simplify it, this system only have 1 planet, and...

Homework Statement THe sun has a mass of 1.99x10*30 kg. Jupiter has a mass of 1.90x10*27 kg and a mean radius of orbit around the sun of 7.78x10*8 km what is the speed that Jupiter travels in its orbit around the sun? Homework Equations fg=(Gm1m2)/d*2 fc=(4pie*2mr)/T*2 The Attempt at a...

Solar system: Double binary star(2 binary stars in a quadruple star system) Kepler A: A big blue star. It is bigger than all the other stars in the double binary system. It will however last longer than our sun just like the other 3 stars will. Kepler B: This is a green star(The green star...

Welcome to my thread. As you have seen from the title, scientists have just discovered a new potentially earth-like planet; it's the closest to us. It's four times the mass of the Earth and it's only 14 light years away. The planet is called Wolf 1060c. Read more about it here. What do you...

What is the physics behind a orbit a cube planet. Does the convential physics including keplars laws and circular motion still apply. Also The cube having a centre of mass posited in the middle of the cude does this mean it can be consider point mass and the same as spherical planet orbit? any...

I'm doing some research for a sci-fi story that I'm writing and hoping that some of you chemists can help me answer a quick question about the material of a hypothetical distant planet. If a distant planet were three times the size of Earth with the same gravitational pull, what would the...

I'm hoping that some of you brilliant scientists can help me understand the realities of a world that I'm building for a story in a distant solar system... I’m building a sci-fi world for a story that takes place on a distant planet that is multiple times the size of earth, but hosts similar...

Homework Statement Astronomers discover a new transiting planet named Jakku. The parent star, Abrams, is known to have a radius equal to ½ that of the Sun’s. a) The transit depth of Jakku is 757 parts per million (757 x 10-6). How large is the planet? Convert your answer into units of Earth...

Or do you some times have to tell a porky pie (lie) even if it is just to keep the peace: darling how do like my hair, oh it looks gorgeous darling, when you really think it looks awful. Or any other white lie, to your boss, GF, spouse.

I found a very interesting exercise for high school students: The atmosphere of a planet changes in height so that if we point a laser in a tangential direction, the light goes around the planet. This can be easily solved (at high school level) by applying the Fermat principle, but is this...