Planets Definition and 510 Threads

Is it mandatory for any planetary system like our Solar system to have a retrograde orbit planet in it's midst ? Is there any upper limit for the same ?:))

Hi folks, I'm writing a story which involves civilisations across multiple planets, and I've been trying to work out the impact of time dilation between them. I'm hoping someone can help me out here (thanks in advance!). (I'm not sure if this exact question may be applicable to one of the...

Does anyone know if there is any internationally agreed method for determining where zero degrees longitude is when mapping other planets etc.?

How can we be sure that when looking for planets there sun is not a perfect sphere and just looks like it is being perturbed by a gravitating body?

From the observation point of Earth, you can say that the sky "moves" while the Earth is still. From this point, an observer on Earth would see a distant galaxy travel a circumference millions of light years lomg around the Earth in only a day - resulting in a velocity faster than light. Special...

After all, dwarf stars are a subset of stars and dwarf galaxies are a subset of galaxies, shouldn't a dwarf planet be a type of a planet?

Source: NASA to Announce Latest Kepler Discoveries During Media Teleconference Livestream Time conversion reference: this post was posted at 7:45 pm EDT. My guess: various roughly Earth-sized exoplanets around dwarf stars, probably at least one in the habitable zone. Edit: More than 1000...

Hey everyone. A little introduction before I ask my questions. I enjoy playing Dungeons and Dragons a lot. For those that don't know, it's a tabletop fantasy game for supreme nerds like myself to enjoy and act out adventures filled with epic magic and battles and more of the such. Lately I've...

Homework Statement Homework Equations I know that Fc = m * centripetal acceleration, where the Fc = the force of gravity The Attempt at a Solution [/B] I was able to use process of elimination to get B for 25 correctly, but I am not able to understand how it is the right answer. How can...

Hello all, Sorry if the question sounds idiotic, but this morning I was watching a program on Jupiter and then I couldn't wrap my head around this. Say a slowly changing gas planet that is cold enough to have very little convection, and that by assumption does not lose its mass to space. Then...

Hi all Today in high school we learned about the procedure by which the Earth reflects the energy given to it by the sun. It did so by the atmosphere, clouds, ect.. Anyways, apparently the process works in such a way that all energy which is absorbed is eventually reflected back into space. If...

In planetary motion, the reduced mass of a system \mu is used in order to study the motion of the planet m in the non-inertial frame of the star M. Using \mu the trajectory of m turns out to be a conic. But this is the trajectory of the planet m as seen from the star M, correct? I read that in...

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

Hi there. So it seems there are multiple reasons for why our galaxy will come to an end. A potential cause is that a black hole will engulf our sun. Let's say that in another galaxy a star is born. There is a chance that a nearby planet will have the potential for sustaining organisms. How...

This i know sounds like a really odd question, but thinking along the Lines that i am.. i guess it has a sense of validity. Could it be Possible, that Planets exist with Dual cores that internally orbit inside a Planet.. or partially joined. Thinking along the lines of Cell structure and how...

I was having a discussion with a friend as to whether or not a planet of rocky composition could exist with an extremely high density. We were thinking something approximately Earth sized, but weighing 4.35 × 10^27 Kg. He says it's impossible, whereas I think it is. Any help anyone can provide...

I've seen a number of people write about planets getting ejected from their galaxies as a result of a gravitational sling caused by a black hole. Is this a real thing? I'm having a hard time understanding how gravity in galaxies works. Could a planet in interglactic space be so far out there...

Does the gravitational force of different planets affect it? I know about the higgs boson and so is that what gives a particle mass?

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...

i calculated the centripetal forces in our solar system but i can't seem to find a connection using the centripetal force formula: Fmpz=(m⋅v2)/r i found out that the mean centripetal force for the planets around the sun is about 10^39, the mean centripetal of the moons around Jupiter is about...

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/

So, i was on the plane going for oxford interviews and i was thinking about what i could be asked. While i was thinking i came up with this one. Suppose the Earth and the moon were at a distance α apart at rest, how long would it take for them to crash into each other. I'm only really...

Homework Statement Two spherical pieces of rock, of masses m1=1.0×1010kg and m2=2.0×1010kg and both of radius r=1500m (2.s.f.) are in deep space a distance of R=1000km (2.s.f.) apart. The only force between them is gravity and they are initially stationary. Find the speed of m1 at collision ...

Homework Statement So there are two planets A and B whose centres are 6r apart. A and B has the same mass M and radius R. What is the minimum velocity(from the surface of B) of the rocket required to launch it from B so that it reaches A ? Homework Equations F=GmM/R^2 The Attempt at a...

An interesting question, which I have just seen for the first time... Does Kepler's 2nd mean that, for instance, both Pluto and Mercury sweep out an equal area over 1 hour? My gut reaction, without calculating anything, is "yes".

I want to know that if we double the mass of the planets and our sun in the solar system,then will it make any difference in the orbits of the planets?will it be necessary to double the distance of each planet from sun?(I am asking it assuming that the sun on doubling of its mass,don't turn into...

On exactly what factors does the rotational angular velocity of a planet depend ? Can a mathematical expression be derived for it ?

I read dark matter makes the stars in a galaxy to move about a same orbital velocity. Why isn't this applicable to our solar system?

There are several examples of it. Western in Star Wars, Firefly, Cowboy Bebop. Medieval things in W40k. I wonder, whether it can be something cool, new thing, to shape another planet like ancient Egypt? Or is it just forced, lame? Cons : It makes that planet less imaginable in the future...

Oxygen is not definitive evidence of life on habitable extrasolar planets The Earth's atmosphere contains oxygen because plants continuously produce it through photosynthesis. This abundant supply of oxygen allows life forms like animals to flourish. Therefore, oxygen had been thought to be an...

An orbit is a fixed path in space around a mass. Once an object gets into an orbit, it would stay there until an outside force pulled it out. Thus, there are only two ways to be in an orbit. Either an object was already in orbit, or it inserted itself into orbit. Since a planet cannot...

Homework Statement A 15 kg satellite has a circular orbit with a period of 4.4 h and a radius of 3.5 × 106 m around a planet of unknown mass. If the magnitude of the gravitational acceleration on the surface of the planet is 1.2 m/s2, what is the radius of the planet? Homework EquationsThe...

If I understand what the BB Theory proposes, all the universe was originally confined to the size of something very small, like a dot or an atom. This small dot or atom or whatever was said to explode, although some say there was no explosion in the sense of a bomb going off, but would be more...

If you look up in the sky you can see both planets and stars. Sometimes you see them flicker, their luminosity oscillates, why does this happen? If we can perceive changes in their brightness from so far away wouldn't the object's brightness be changing in unrealistic amounts? shouldn't the...

Hi As far as I know the Earth orbits around the Sun Earth barycenter while the Sun orbits the Solar System BaryCenter formed by the changing center of mass of the Solar system. So even while the Sun orbits the SSBC and Earth orbits the Sun-Earth BC it would not be true to say the Earth...

I have reasons that have convinced me that Mars would be better, but I want to know what everybody else thinks.

Homework Statement Planet 1 orbits Star 1 and Planet 2 orbits Star 2 in circular orbits of the same radius. However, the orbital period of Planet 1 is longer than the orbital period of Planet 2. What could explain this? A) Star 1 has less mass than Star2. B) Star 1 has more mass than Star 2 C)...

Homework Statement [/B] Consider a spherical planet of uniform density ρ. The distance from the planet's center to its surface (i.e., the planet's radius) is Rp. An object is located a distance Rfrom the center of the planet, where R<Rp. (The object is located inside of the planet.) Find a...

Hello! I am learning about refracting telescopes and am slightly confused. I have read that a refracting telescope will magnify planets, but not change their brightness, but will not magnify stars as these will remain as point objects. It just makes the stars appear brighter. I am slightly...

I have read in a book that the reason Earth-size planets become candidates for habitable planets is because of their capability to hold an atmosphere; a planet smaller than Earth would have a thinner atmosphere and otherwise if it is larger. My question is, does this size matter because of its...

I understand that it's possible to calculate the age of terrestial planets through radioactive dating their soil. However, the gas planets present a different challenge since we cannot currently land on them. Any ideas on how to calculate their ages in a different manner?

Hey guys I am here to share some of my THEORIES... Is there any theory that anyone can point me to that is similar to mine: " As I watched a movie about Saturn today I came to realization of what a Planet could be. My theory is that a planet is a giant entity that even has some form of a...

Is there a website where data on extra solar planets is summarized? Questions such as: how far away are the parent stars from here?, what fraction of nearby stars have planets?, what fraction of the planets are "earth-like?, how many in "goldilocks zone?

Why do Moons revolve around planets? If because of gravitational pull, why won't they clash with planets. Please help me get answer to this question!?

Hello. I am by no means knowledgeable in General Relativity. With that said: What if "curvature of space-time" actually is the force fields of massive objects, like the magnetic field of earth? Why must space-time necessarily have to be "bent"? Is there really only one way to look at the nature...

We can see galaxies/planets light years away determine their composition such such as if they have water et cetera. My question is if light takes billions of years to reach us from there how is that we can determine such things? Is the speed at which a telescope can zoom faster than the speed at...

Homework Statement A spaceship in outerspace has a donut shaped with a 500 m outer radius. The inhabitants stand with their heads towards the center and their feet on an outside rim. Over what time interval with the spaceship have to complete one rotation on its axis to make a bathroom scale...

How do planets continuously rotate on their axis or revolve around stars ? Do the energy they consume for this continued motion gets expelled as heat ?

If you had a planet with the exact same mass and radius as the Earth, and adjusted the gravity constant to some value five-hundred million times larger, the schwarzschild radius should become considerably big, right? Instead of being about 8 millimeters, it would now be about 60 to 70 percent...

Hey! :o I want to write a function for the collision of the free-floating planet with identifier ffp and the planet with identifier as. The collision has as a result the destruction of both planets. Specifically, the free-floating planet with identifier ff will be deleted from the free-floating...