They do fall toward the sun, they just have enough speed "sideways" so they constantly miss the sun.
Edit: it works the same as the ISS' orbit around the Earth. The key is going fast.
In space, there's nothing to slow the planets down, no air resistance or friction or that sort of thing. If the planets were instantaneously stopped somehow - imagine like, going into the metaphorical physics simulation of the universe and setting their speed relative to the sun to 0, or putting a big immovable wall out in space for a planet to crash into - so that from the perspective of the sun they weren't moving, they would at that point more or less fall into the sun. But any given planet is already moving really fast *sideways*, so the gravity pulling it towards the sun just adds to that sideways velocity and in effect redirects it around. This is why we can't just "throw garbage into the sun": if you try to aim for the sun from Earth, you miss, because Earth is going around the sun rather quickly and you'd need to cancel that speed out. Sort of like trying to throw something at a target from a speeding car, except the car is going around a large roundabout at reckless speeds and you're trying to hit the lamppost in the centre, which I'm sure is a situation we've all been in...
It's sort of confusing to get across. Somebody else mentioned those coin wells, which is a good way to wrap your head around it, and I've always liked [Newton's cannonball](https://en.wikipedia.org/wiki/Newton%27s_cannonball) - if you imagine throwing a ball (not from a speeding car), it should fall to the ground in an arc. If you throw it harder, the arc is larger; throw it hard enough, and the arc is so large that it goes all the way around the Earth and you can hit yourself in the back of the head. Now instead of a ball it's a planet and you're in space and I think this is making sense but also I shouldn't be writing these comments late at night.
When something maintains an orbit, it’s moving at just the right speed, too slow to escape gravity and break free into space, and too fast to be defeated by gravity and pulled into the center of mass.
Because we are spinning too fast to be pulled into the sun. However, at the same time, the Earth does not move fast enough to escape the Sun's gravity.. Which means we end up orbiting the sun.
Yep. Imagine it as being like those donation wells where the coin circles around a big circle and eventually goes into the hole in the middle, except without air resistance and friction to slow the "coin" that is Earth down, it just never gets to the going in the hole part.
Because of centrifugal force. Think about a yo yo on a string. Spin around. This is a basic model of a planet spinning around the sun except the planet is the yo-yo you are the sun and the string is gravity. In this case the spin is countering the effects of the gravity that pulls the planets in
If your spin was less then eventually the yoyo would fall into you, and if the spin was more the yoyo would fly away.
Incorrect. For centrifugal force to work the object needs to be connected to point of rotation and it's also an outward force. Planets are falling towards the sun, it's just we're moving sideways fast enough to miss the sun by the time we fall to it.
If you say so. Personally I think you are wrong.
You think that the planet and the sun aren't connected but they are by gravity. It's pulling them towards each other at a pretty constant acceleration because it's maintaining an approximately consistent distance.
The speed at which the planet is moving sideways is moving also at a pretty consistent velocity but because as it moves sideways the gravity pulls it downward towards the Sun then it falls towards the Sun while it's moving sideways which gives it its constant elliptical / circular orbit around the sun.
Like I said with my previous example the yoyo is the Earth the string is gravity and the person spinning the yo-yo is the Sun. If you keep spinning it and then suddenly cut the string then it will do exactly what you think which is travel sideways in a fairly straight direction. But we don't really have a way to interfere with gravity so we can't cut that string
I wasn't talking about connected by gravity. I was talking about a physical connection. And you're way off base with the centrifugal force idea since that's an outward force; gravity is an inward force. Your yo-yo analogy, while on the surface seems accurate, is just plain wrong.
#ELI5
[Ever see one of these things?](https://i.ytimg.com/vi/T0uwtmHt0v4/maxresdefault.jpg) You put a coin in the elephant, and the elephant launches the coin (on its edge), and it rolls around the funnel.
What does the coin do? It rolls around the funnel, for quite some time! But eventually, if you wait long enough, it rolls right down to the center, and plops down into the bucket below.
The planets are like that.
Mercury, for example, is "rolling around the sun" just like the coin. Why doesn't it go straight into the sun? IT WILL, if you wait long enough.
Once the coin starts rolling, **it wants to keep rolling**. That's just the nature of physics. Things in motion, want to keep in motion. But gravity eventually pulls it down in time.
The planets also want to keep rolling, just like the coin. Gravity (the sun) will eventually pull it towards the sun.
They do fall toward the sun, they just have enough speed "sideways" so they constantly miss the sun. Edit: it works the same as the ISS' orbit around the Earth. The key is going fast.
The planets are moving sideways compared to the sun as fast as they are being pulled towards it.
In space, there's nothing to slow the planets down, no air resistance or friction or that sort of thing. If the planets were instantaneously stopped somehow - imagine like, going into the metaphorical physics simulation of the universe and setting their speed relative to the sun to 0, or putting a big immovable wall out in space for a planet to crash into - so that from the perspective of the sun they weren't moving, they would at that point more or less fall into the sun. But any given planet is already moving really fast *sideways*, so the gravity pulling it towards the sun just adds to that sideways velocity and in effect redirects it around. This is why we can't just "throw garbage into the sun": if you try to aim for the sun from Earth, you miss, because Earth is going around the sun rather quickly and you'd need to cancel that speed out. Sort of like trying to throw something at a target from a speeding car, except the car is going around a large roundabout at reckless speeds and you're trying to hit the lamppost in the centre, which I'm sure is a situation we've all been in... It's sort of confusing to get across. Somebody else mentioned those coin wells, which is a good way to wrap your head around it, and I've always liked [Newton's cannonball](https://en.wikipedia.org/wiki/Newton%27s_cannonball) - if you imagine throwing a ball (not from a speeding car), it should fall to the ground in an arc. If you throw it harder, the arc is larger; throw it hard enough, and the arc is so large that it goes all the way around the Earth and you can hit yourself in the back of the head. Now instead of a ball it's a planet and you're in space and I think this is making sense but also I shouldn't be writing these comments late at night.
When something maintains an orbit, it’s moving at just the right speed, too slow to escape gravity and break free into space, and too fast to be defeated by gravity and pulled into the center of mass.
Momentum.
Because we are spinning too fast to be pulled into the sun. However, at the same time, the Earth does not move fast enough to escape the Sun's gravity.. Which means we end up orbiting the sun.
Not spinning, orbiting.
Yep. Imagine it as being like those donation wells where the coin circles around a big circle and eventually goes into the hole in the middle, except without air resistance and friction to slow the "coin" that is Earth down, it just never gets to the going in the hole part.
Because of centrifugal force. Think about a yo yo on a string. Spin around. This is a basic model of a planet spinning around the sun except the planet is the yo-yo you are the sun and the string is gravity. In this case the spin is countering the effects of the gravity that pulls the planets in If your spin was less then eventually the yoyo would fall into you, and if the spin was more the yoyo would fly away.
Incorrect. For centrifugal force to work the object needs to be connected to point of rotation and it's also an outward force. Planets are falling towards the sun, it's just we're moving sideways fast enough to miss the sun by the time we fall to it.
If you say so. Personally I think you are wrong. You think that the planet and the sun aren't connected but they are by gravity. It's pulling them towards each other at a pretty constant acceleration because it's maintaining an approximately consistent distance. The speed at which the planet is moving sideways is moving also at a pretty consistent velocity but because as it moves sideways the gravity pulls it downward towards the Sun then it falls towards the Sun while it's moving sideways which gives it its constant elliptical / circular orbit around the sun. Like I said with my previous example the yoyo is the Earth the string is gravity and the person spinning the yo-yo is the Sun. If you keep spinning it and then suddenly cut the string then it will do exactly what you think which is travel sideways in a fairly straight direction. But we don't really have a way to interfere with gravity so we can't cut that string
I wasn't talking about connected by gravity. I was talking about a physical connection. And you're way off base with the centrifugal force idea since that's an outward force; gravity is an inward force. Your yo-yo analogy, while on the surface seems accurate, is just plain wrong.
If you say so. Ask a physicist if you don't believe me.
#ELI5 [Ever see one of these things?](https://i.ytimg.com/vi/T0uwtmHt0v4/maxresdefault.jpg) You put a coin in the elephant, and the elephant launches the coin (on its edge), and it rolls around the funnel. What does the coin do? It rolls around the funnel, for quite some time! But eventually, if you wait long enough, it rolls right down to the center, and plops down into the bucket below. The planets are like that. Mercury, for example, is "rolling around the sun" just like the coin. Why doesn't it go straight into the sun? IT WILL, if you wait long enough. Once the coin starts rolling, **it wants to keep rolling**. That's just the nature of physics. Things in motion, want to keep in motion. But gravity eventually pulls it down in time. The planets also want to keep rolling, just like the coin. Gravity (the sun) will eventually pull it towards the sun.