## Science!

### Educational

A group for those interested in science from the vast expanse of the universe or technology.

Is the Sun really so powerful?

I heard many times that in fact power output of the Sun is very low compared to it's size. But people usually consider Sun as something monstrous with almost infinite energy.

Posted by CommanderDef on Oct 7th, 2012

The Sun produces energy by running thermonuclear reactions. But most of it's mass are protons and proton+proton fusion is the least efficient of all. Of course there are reactions with complex atoms, but that is quite minority.

So, let's make a simple math. According to wiki and some more websites, power output is about 3,827×1026 Watts. Mass is said to be about 1,9891×1030 kg. That makes about 1,92x10-4 Watts per kg.

For ilustration, imagine a man of weight 100 kg. That man has to pull 19,24 gram thing one meter far from it's original position by one second to have the same watt/kg output. Right? Well, according to some sites I visited, human metabolism radiates heat (depends on temperature, weight and many other things) about 100-200 W, which is anyway much more heat/mass than our star.

Ok, now stop thinking about Sun made of human bodies xD. Funny fact, isn't it? So do you still think it is so powerful?

ElfFriend Oct 8 2012, 2:37am says:

wow that's a neat fact!! exactly what the Science! group is for:D

Author
CommanderDef Oct 8 2012, 4:06am replied:

I find it interesting. And I also find your presence here interesting. Would you like to become a part of research?

Creator Online
rkraptor70 Oct 8 2012, 5:16am replied:

*Sigh*
Here we go again. So much for discussing about the sun...

Author
CommanderDef Oct 8 2012, 1:41pm replied:

That comment has nothing to do with his personal beliefs, only with my personal opinion about the guy.

ElfFriend Oct 9 2012, 1:33am replied:

What do you mean part of research?

Creator
Cervi_Messias Oct 9 2012, 12:05am replied:

yes it is a neat fact, and yes the science group is for exactly that- it is for science

now i am guessing you have an alterial meaning to your comment,
I will warn you once dont try and cause trouble elf. if you want to dicuss science without involving myth and superstition then it is ok, but so far all you have shown us in this group is your desire to religious troll.
Cheers
Deer_hunter

ElfFriend Oct 9 2012, 1:31am replied:

Hay I LOVE science, I know I should be sleeping but I decided to check my iPhone one last time, it's only 11:30 pm:)

Anyways only an idiot would not like empirical science.

ElfFriend Oct 9 2012, 1:35am replied:

Might I know what troll downvoted my comment? I spoke nothing of creation/evolution, only hinted that we cannot use science to explain something that can be interpreted either way, so we should focus on what we can test, observe and repeat.

Creator
Cervi_Messias Oct 9 2012, 2:25am replied:

i just voted you back up to one, are you happy now?
and it really cant be interpted either way.
its either interpeted as science ir magic rainbows which arent science.
and we dont allow magic rainbows here.

ElfFriend Oct 10 2012, 2:19pm replied:

Thank you

Creator
Sarge_Rho Oct 13 2012, 2:04pm says:

proton + proton is one of the more efficient ones. The closer you get to Iron, the less efficient your reaction becomes, this goes for fission starting at the heaviest element, and for fusion starting at the lightest element.

Author
CommanderDef Oct 14 2012, 7:03am replied:

You are both right and wrong. Proton + proton is ineffective, compare it with T+D, or T+T. Also notice that Lithium and Helium can be fused on higher energy and is also more efficient than lighter particles.

But you are right about heavy elements, in case of heavier than Iron, you actually need energy and not produce.

ElfFriend Oct 15 2012, 1:15am says:

i just though of an explanation as to why the sun isn't powerful.

if it was powerful then it would be less massive, which would then mean that its gravity would have been smaller (from what i know of gravity is that it greatly depends on the objects mass, but correct me if im wrong) so that would then mean that it would loose its planets or burn them if it produced more heat by a more effective process. just something to think about:D and of course you know what else i might have put here...but i dont like having my comments deleted.

Author
CommanderDef Oct 15 2012, 8:53am replied:

It is so powerful because it is so massive. Also first was the Sun. Planets are products of local gravity instabilities in 'dust' around. If Sun was bigger, there would be less planets and more further of the center. Also by the time when Sun burns all protons and start to fusion of heavier elements in larger scale, it's power output will rise and it will burn planets around. But that is far in future, in the meantime, we have enough time to destroy ourselves. Anyway, it will happen - making your unwritten sentence debunked.

Creator
Sarge_Rho Oct 17 2012, 1:24pm replied:

The more massive a star, the shorter it lives, and the more powerful it is. Red dwarfs can live for hundreds of billions, if not several trillion years, while blue hypergiants live 100s of millions of years at most.

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