# The Sun?

1. Feb 20, 2004

### Guard

How can the sun have much mass if it's just a bunch of gasses? And also what keeps the sun in a circlular shape? I've always wondered.

2. Feb 20, 2004

### HallsofIvy

Actually, its worse than that! How can the sun have much mass if it's just a bunch of hydrogen? (The lightest possible gas.)
Answer: it's one heckuva lot of hydrogen! If you get enough of anything, even the lightest element in the universe, it will have a very large mass!

What keeps it spherical (better than "circular")? The same thing that keeps planets spherical: the gravitational attraction of its parts for each other.

3. Feb 20, 2004

### Loren Booda

The Sun has, on average, density slightly less than that of water (but 90 times greater at its center since its mass, thus gravitation, is so great, thereby maintaining fusion). The Sun has approximately 10 million times the volume of the Earth, and 300,000 its mass.

4. Feb 20, 2004

### chroot

Staff Emeritus
Actually, the sun's average density is about 1.4 grams per cubic centimeter, about 40% denser than water.

- Warren

5. Feb 20, 2004

### ahrkron

Staff Emeritus
Just to clarify (although this may be what you had in mind):

At the center of the sun (or any celestial body), you have the least gravity, since you are pulled the same in all directions; if you could build a spherical room in the center of the sun, it would be a zero-gravity place, much as what happens when you introduce a charge inside a charged spherical shell.

At the center, there is, however, the largest pressure, due to all matter being pulled towards that point.

6. Feb 20, 2004

Staff Emeritus
At the center of the Sun, true, you have no gravity, but you do have the pressure, which the gravity acting in the rest of the Sun, brings to the center. It is the pressure, not the gravity itself, which raises the temperature and makes fusion possible.

7. Feb 20, 2004

### FZ+

A ton of feathers still has a mass of one ton.

Question: Is the sun actually spherical? I think it spins somewhat, which would make it slightly fatter around the equator.

8. Feb 20, 2004

### chroot

Staff Emeritus
It's an oblate spheroid.

- Warren

9. Feb 20, 2004

### KingNothing

Isn't the sun something like 99.99% efficient per year? As in, each year it would have 99.99% of its mass that it had last year at the same time?

10. Feb 20, 2004

### chroot

Staff Emeritus
It loses far less than 0.01% of its mass yearly.

- Warren

11. Feb 20, 2004

### JasonRox

You can not escape gravity in any way. It's just impossible.

Gravity is everywhere, and as a matter of fact, your body has gravity.

12. Feb 20, 2004

### Loren Booda

Thanks for the corrections, folks.

13. Feb 20, 2004

### AnthreX

eventually like 5 billion years later the sun would die out right ?
i guess i dont have to worry about that

this has nothing to do with the sun but.. the MOON

i heard that its comming towards earth very very slowly

is it true? if it is true how much is it moving towards the earth?
everyday ?

14. Feb 20, 2004

### Nereid

Staff Emeritus
bye bye Moon!

It's actually receding ... at ~3 cm/year.

http://scienceworld.wolfram.com/astronomy/Moon.html

However, it'll be back (it's all due to conservation of angular momentum, and neither the Earth nor Moon being a perfectly rigid perfect sphere)

15. Feb 22, 2004

### ramonm

THE SUN'S MASS ETC..

One has to note that the Sun is a body made of gas mainly hydrogen which then is consumed by the Sun itself to power it's Nuclear reactions. This is then converted to helium. Although hydrogen is light one has to consider the immense size of the Sun which obviously has a huge mass. I don't know if this example is valid but this is liek having a pack of papers, one paper is light but when amounts increase the pack get's heavier. Now about the sun having circular shape. This is like all otehr celestial bodies they have a circular shape because of the effect of the gravitational field.

I am not an advanced PHYSICIST but I hope my post was correct.