Why do planets orbits stars instead of other things in the universe?

Question

Just got a little curious here. So I was watching habitable planets orbiting a star in a far away solar system then a question bubbled into my head. Why do these planets have to orbit a star? Why does it have to be a star? There are a lot other things in the universe but why does it have to orbit a star? Does a star have a unique gravity around them that attracts and keeps these planets around them?

Answer 1

the reason anything goes around anything else is gravity. the bigger the object, the more "pull" it has. for example: the moon goes around the earth, the earth goes around the sun, the sun revolves around the galaxy, and the galaxy and other galaxies interact based upon there movements (but they actually can crash into one another forming an even larger one) and so on. everything is relative...

Answer 2

Because stars are so massive is the main part of the answer. The earth could in principle orbit Jupiter - but the sun's gravity dominates any interaction between the two planets. Gravitational attraction is proportional to the product of the two masses, by the way, in case you didn't know.



Another kind of answer comes form the way planets form. They are just the 'left-overs' from the formation of stars. Both stars and planets from from big disks of gas and dust, which (for reasons connected with simple statistics) are like spinning plates. So the material which forms the planets is already orbiting the central star (or the material which will become the central star) long before any planet actually forms.

Answer 3

The star's "unique" gravity is that it is such a larger pull than anything else because of its mass. A star is the basically the fat @ss of the Universe. Because that its gravitational pull is larger than anything else besides black holes, which were once stars.

The moon orbits the Earth because in the many theories of how the moon was formed, it was close enough and is small enough that Earth's gravitational pull affects it and keeps it in orbit. The sun and all the other planets though are pulled into the sun's orbit because its pull is soo strong. The planets gravitational pulls do affect one another though especially the larger planets but the sun is the strongest.

Answer 4

All objects orbit around a common centre of gravity. The more massive an object the closer the centre of gravity is to the object. Stars are so much more massive than planets that planets orbit around them.



You should note that planets themselves often have moons orbitting around them for the same reason.

Answer 5

A stars gravitational pull is greater than an other object except for black holes. Super massive black holes are at the center of almost every galaxy and stars will actually orbit them and at the center of our galaxy is also a super massive black hole that has all planets stars and everything in this galaxy orbiting it while slowly being swallowed up by its pull. We wont have to worry about being pulled into it until trillions of years from now. Gas giants such as jupiter have satellites the size of our planet orbiting them. A planet is classified as such because it orbits a star and a satellite is classified because it orbits a non burning object such as a planet. I know i gave more info than needed but i always do.

Answer 6

Mainly because planets form around stars. Stars form when a portion of a cloud of gas and dust collapses under its own gravity and becomes dense enough in the center to start a fusion reaction. Meanwhile, other portions of the cloud, already orbiting the star forming in the center, coalesce into planets.



And, if you think about it, there aren't a lot of other compact massive objects in the universe other than stars suitable for a planet-sized object to orbit.

Answer 7

gravity is a constant force dependent on mass, am sure a few planets do orbit neutron stars, black holes, quasars and some are almost certainly hypervelocity planets not orbiting anything but stars are easiest to detect planets orbiting as they dim the star a tiny bit as they pass, there are many trillions of stars out there so its easiest to spot planets around them space is really gigantic so looking anywhere else would be extremely frustrating! also if it wasnt orbiting a star, how could it be habitable as would be freezing cold and lifeless!

Answer 8

Planets and stars, including collapsed stars, including black holes are the only things that have enough gravity to hold planets in orbit. Some planets have no orbit at all, but drift across space on their own course across the galaxy. They are known as orphan planets. Lonely, but it's not like they have feelings.

Answer 9

The definition of planet set in 2006 by the International Astronomical Union (IAU) states that, in the Solar System, a planet is a celestial body which:

is in orbit around the Sun,

has sufficient mass to assume hydrostatic equilibrium (a nearly round shape), and

has "cleared the neighbourhood" around its orbit.



The official definition of "planet" used by the International Astronomical Union (IAU) only covers the Solar System and thus does not apply to exoplanets. As of April 2011, the only definitional statement issued by the IAU that pertains to exoplanets is a working definition issued in 2001 and modified in 2003. That definition contains the following criteria:

Objects with true masses below the limiting mass for thermonuclear fusion of deuterium (currently calculated to be 13 Jupiter masses for objects of solar metallicity) that orbit stars or stellar remnants are "planets" (no matter how they formed). The minimum mass/size required for an extrasolar object to be considered a planet should be the same as that used in our solar system.

Substellar objects with true masses above the limiting mass for thermonuclear fusion of deuterium are "brown dwarfs", no matter how they formed or where they are located.

Free-floating objects in young star clusters with masses below the limiting mass for thermonuclear fusion of deuterium are not "planets", but are "sub-brown dwarfs" (or whatever name is most appropriate).

This article follows the above working definition. Therefore it only discusses planets that orbit stars or brown dwarfs. (There have also been several reported detections of planetary-mass objects that do not orbit any parent body. Some of these may have once belonged to a star's planetary system before being ejected from it; the term "rogue planet" is sometimes applied to such objects.)

Answer 10

Because a star is so large and heavy it actually pulls object toward its center. An object can only orbit something in space much larger than it. Such as the moon orbits earth. We fall towards earths core but luckily the ground stops us. It has to be a star because stars are the largest objects in space.

Answer 11

Many planet like objects likely orbit our galaxy instead of specific stars, but they need to orbit a star so we can detect them. Stars do have an optimum amount of gravity to facilitate planets orbiting them, but even tiny asteroids sometimes have smaller objects orbiting them. Neil

Answer 12

Because larger the mass of something then more gravitational pull/force & any objects having small mass then that larger mass object orbit/circles around that larger mass object. In terms of planets & stars, almost all stars are very huge so it pull everything including planets by it's gravitational force. If another massive object(anything) is near to our planet earth then it's possible that our earth could be pull by that massive thing because of its gravitational force.

Answer 13

"Other things in the universe", such as what? What else is there for a planet to orbit? Another planet? Then it would be a moon, or a binary planet.



What else is there for a planet to orbit?

.

Answer 14

Do Planets Orbit Stars

Answer 15

Gravity and force. The bigger the mass the more gravity and force it has. Its most likely there is even a black hole in every spiral galaxy which is what gives them their shape. There is also the blanket theory too. Google it if you want to know the answer lol. Too much to explain.

Answer 16

Im assuming its because stars are so massive and have a far more powerful gravitational pull than other solar bodies. But im no astronomer so i could be completely wrong lol:)

Answer 17

What "other things"are there with a lot of mass?

Stars, dead stars and black holes.

If it is that big it is or has been a star.

Answer 18

Because no matter what your girlfriend says, size does matter.