how does the gravity of the sun keep a planet in orbit? explain?

Question

the question's pretty self explanatory but i'd greatly appreciate detailed and well explained answers.

Answer 1

Kelly D gives a good explanation, but leaves out one important fact: if you throw a ball straight up it will always fall back on the earth in the exact same place (assuming no wind) regardless of whether there was friction (else it goes off and never returns because it's velocity is greater than the escape velocity, which isn't the case we're interested in).

Putting the ball in orbit (or a satelite or a planet) requires you throw it forward as well as up so that as the ball "falls" back to Earth, the surface of the Earth curves away from the ball in such a way that the ball never hits the surface. So the ball falls forever assuming no loss of energy due to friction.

So the planets and all other orbiting bodies are in a state of "freefall" around the Sun (or whatever they're orbiting), just as Kelly says.

Now, what keeps them in orbit and not spiraling down towards the Sun is Conservation of Angular Momentum. If Angular Momentum isn't conserved, the planets would get closer or further away depending on the situation. Angular Momentum conservation is also the reason that all the planets are, for the most part, all lying in the same plane.

For more info on planetary dynamics look into Kepler's Laws. For a mathematically advanced treatment (i.e., Calculus students and above), look up Lagrangian Dynamics of Planetary Motion.

EDIT:
Emmetgolf's answer is not correct. It's so far out there, I don't even know where to begin on breaking it down. Most of that stuff you don't have to understand in order to understand gravity. The equations for planetary motion that reproduces the orbits of the planets so well are so much simpler than any of that.

Answer 2

Think about throwing a ball in front of you. It travels forward and also down in a path called a "parabola". If you threw the ball higher up, it would go further forward before ending up on the ground. If you threw it from such a distance that there was no air to give friction, it would go further.
The planets are "falling" in the same way except they are so high up from the Sun they never hit it, they end up travelling in a nearly circular orbit.
They do not fall in because they are hardly losing any energy at all to friction as there is no air in space and only a small amount of dust.

Answer 3

Tie a rock to the end of a string. Start swing the rock around in a circle. If you're the Sun and the Rock a planet, this is a good analogy of how the Sun keeps a Planet in orbit.

The only difference, Gravity is the string and it's called an "Action at a distance" force.

Answer 4

gravity is all according to mass case in point if the earth replace into as small as a marble it is going to suck interior the photograph voltaic gadget it replace into the two that or the galaxy the standars equation for gravity is Gravitational rigidity = (G * m1 * m2) / (d2) the place G is the gravitational consistent, m1 and m2 are the hundreds of the two products for which you're calculating the rigidity, and d is the area between the centers of gravity of the two a lot. u can evaluate gravity to magnets they artwork further. gravity pulls issues in simply by fact each and every particle of count attracts the different particle with a rigidity it extremely is immediately proportional to the made of their a lot and inversely proportional to the sq. of the area between them. the suns gravitational pull is more advantageous then the planets gravitational pull simply by fact of it mass the solar additionally revolves on an axis simply by that the gravitaional pull makes the planets pass comparable concept with earth and the moon.

Answer 5

An object will travel in a straight line if no force acts on it. The force of gravity from the Sun pulls on the Earth so that its path curves instead of going in a straight line. The amount it curves is just enough (and not too much) so that the Earth travels in nearly a perfect cirlcle.

Answer 6

To understand the forces of gravity, you first have to have a concept of space. Space, far from being a void or vacuum, is basically comprised of light particles, gravity, and an average of 1 atom per cubic centimeter held in place by various gravitational forces acting on them. The number of atoms per ccm varies with the number growing larger as you get closer to something like the sun. The number is also larger inside the boundaries of a galaxy like the Milky Way. The main idea is that if you stack ccm blocks on top of each other stretching out to infinity or even just for 13.7 Billion light years, depending on whether you think the universe is infinite or not, you will have gazillions of atoms suspended in their lighted gravitational gels lined up with every square centimeter of the surface of any object floating in Space. A gazillion atoms is a significant mass. If you multiply this by the surface of the sun it turns into gazilliongazillions. Fortunately, the sun is not the only thing causing gravity and the gravitational effects of all of the other objects in the universe keep all of the atoms from crashing onto the sun obliterating it.

Then you have to have an idea of what is going on with the sun. The sun's energy is fueled by heat caused by compression. As the nuclear reactions at the core of the sun use the sun as fuel, it compresses more causing more heat causing more nuclear actions causing more compression. The sun is constantly compressing.

As the sun compresses, it attempts to form a vacuum around its surface. Space won't allow this so a gazilliongazillion atoms along with their lighted gravitational gels shift towards the sun. As space mass shifts towards the sun, it too begins to compress and the distance between atoms grows increasingly less as they strike the surface.

The earth, which is also in a state of contant compression, runs into this spacial mass shifting towards the sun and gets deflected, from the straight path it wants to take, to a path that turns towards the sun. Fortunately, the earth's mass and momentum allows it to penetrate the shifting space mass just enough to keep it in orbit. A little bit faster and it floats off into space becoming a part of the space gel. A little bit slower and it crashes into the sun. An object like Pluto enounters a less dense shifting space mass and doesn't have to have as much momentum or mass to stay in orbit. Something closer to the sun has to be moving much faster or be more massive, or a combination of the two, in order to penetrate the increasing density of the space mass shifting towards the sun.

This also applies to the moon in orbit around the earth or anything else in the universe. As all objects move through space, the space gel becomes fuel to replace the mass that they are using as fuel from their own mass.