How close can something/someone get to the sun before its gravity sucks them in?

Question

Is there even gravity on the sun? What's the closest something can get to the sun?

Answer 1

Oh, yes, the Sun has gravity. Does it ever. Its gravity is 330,000 times as strong as Earth's, since the Sun is that many times bigger.

But you can't give a certain distance beyond which you can get sucked into the sun. A comet 1 light year away could be headed directly for the Sun and so it eventually will get sucked in. A speeding asteroid could get within a half million miles of it and get away from it. It depends on how fast the object is moving and in which direction. If it is moving really fast, it will exceed escape velocity and leave the Solar System. If it is not moving fast enough or if it is headed drectly to the Sun's surface, it will get sucked in. Most objects try to escape by moving parallel to the Sun, while the Sun tries to pull it in. The resulting balance causes the object to orbit the Sun. That explains planetary motion in the Solar System.

What's the closest something can get? I say the photosphere. After that point, drag from the Sun's atmosphere will draw the object into the center of the Sun. This will happen to Mercury and Venus 5 billion years from now when the Sun expands into a red giant, and it may happen to the Earth as well.

Answer 2

The Sun's gravity is pulling on you all the time, but it will not "suck you in". Solar gravity causes about 1/3 of the tidal force we get on Earth. The Moon has twice the tidal pull of the Sun and when the two are in a line, we get spring tides. When they are at right angles we get smaller "neap" tides.

The Sun, if it were a solid ball you could walk on, would have over 28 times the gravity that the Earth has on its surface. If you were to orbit the Sun very closely, you could probably get within a quarter of a million kilometers or so, but you would encounter two problems.

First, the photosphere supports huge clouds of plasma that can reach far into space, and you will likely feel some deceleration from passing through the material, like passing through the upper atmosphere of Earth on reentry.

Second, the heat would destroy your craft unless you could reflect most of it and insulate the ship very well.

Another potential problem is the magnetic field - it is powerful and complex, so it might induce large currents in your spacecraft if it were made of metal. This would slow your travel and make you drop closer to the Sun.

So we see a couple of effects that would cause your ship to get closer to the Sun, but they are not related to gravity. Friction from plasma and resistance from the generator effect from the magnetic field would both rob your ship of forward movement.

Answer 3

The sun only has a small amount of gravity and this is actually offset by the solar wind. You see the sun's rays actually push things away from the sun. The closest that you can get to the sun without burning up is approximately 69 miles

Answer 4

Yes, the sun's gravity is why the earth stays in orbit. There is no fixed distance where the sun 'sucks things in'. It's a trade-off between distance and how fast something has to go to get away (the escape velocity). If you are at a distance of R and the sun has mass M then the velocity needed is
sqrt(2GM/R)
where G is the gravitational constant.

Answer 5

In theory it is possible to orbit one foot above the surface of the Sun just like it is possible to orbit 1 foot above the surface of the Earth (neglecting friction from the atmosphere). But since the Sun's gravity is stronger than Earth's, you would have to orbit at over a million miles an hour that close to the Sun.

Answer 6

All of the previous answers are great and I have learned a lot from reading them. But I wanted to answer your quesiton diectly.

Question: How close can somethign get to the sun before the gravity sucks them in?
Answer: The Sun's gravity pulls at every object in our solar system. The amount of pulling force applied to that object depends on its own size (or mass) and how close it is to the Sun. If you have the power to counteract the force of the sun's gravity (thruster rockets) you can get as close as your rockets will let you.
Another way to avoid getting sucked toward the sun is through momentum. If you are moving around the Sun, your momentum is the energy that counteracts the sun's gravity. You are trying to pass by, and the sun is trying to pull you in, and if the force of the sun's gravity and the momentum of your mass are in balance, you will achieve orbit around the sun. If one is greater than the other, you will move in that direction, spiraling toward the sun or spiriling away from the sun.

Question: Is there even gravity on the sun?
Answer: Yes. All of the planets in our solar system are being pulled by the sun's gravity, but their momentum is keeping them in orbit.

Question: What is the closest something can get to the sun?
Answer: It depends on your heat shield - or on the amount of thermal radiation you can deflect away from the craft you are in. On the surface of the moon, during the day, the temperature is 253 degrees. Water boils at 212 degrees. The closer you get to the sun, the more thermal energy you have to deflect to keep your craft from melting or burning. The closest planet to the sun is Mercury. It gets as hot as 870 degrees during the day. It zips around the sun in only 88 days, compared to our 365.

In addition to the heat, there is also dangerous radiation to contend with that we don't often consider, as our ozone layer protects us from most of that. So you hear shield has to deflect radiation as well.
The link below describes conditions on Mercury, to help you understand the physics behind being closer to the sun.

Great question! Keep them coming!
:-)

Answer 7

Don't know about how close,but it has tremendous gravity. If it didn't even distant Neptune wouldn't be held in it's grasp.

Answer 8

Once you passed Mercury,you would not get very much further,Probably about 250,000 miles past.

Answer 9

I'm not goin there!