Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Descan]

Not particularly. Sun already makes up >99.8% of the solar system's mass. It probably has a Saturn or two's worth of iron in it already.

Edit: Yep. Saturn is about 5.683x10^26 kg, while the iron content of the Sun, 0.14% of 1.989x10^30 kg is about 2.7846x10^29 kg

So there's about 480 times as much iron already in the Sun as there would be in a Saturn-sized mass of iron.

[Bauglir]

A fun story I once read involved using Triton as a heatshield to descend into the Sun for long enough to reprogram a supercomputer so vast that it occupied some significant fraction of the Sun's volume. It was a one-way trip, of course, and then they built another Triton, but the Sun was pretty much fine afterward.

[Descan]

Not particularly. Sun already makes up >99.8% of the solar system's mass. It probably has a Saturn or two's worth of iron in it already.

Edit: Yep. Saturn is about 5.683x10^26 kg, while the iron content of the Sun, 0.14% of 1.989x10^30 kg is about 2.7846x10^29 kg.

So there's about 480 times as much iron already in the Sun as there would be in a Saturn-sized mass of iron.

Just to make sure the actual math was seen (and can be laughed at if it's wrong )

An extra Saturn's worth of iron would be a rounding error at this scale.

[wierd]

Yup.  Thankfully our star is pretty small, so it cant fuse heavier than iron at a huge loss, like larger stars do. It hits iron nuclei, and then stops as a dense plasma of the stuff.

I still find it curious that so many people have difficulty with the concept of entropy.  To me, the elephant in the room is the dark energy that is forcing our universe apart at INCREASING rates.  Sure, it's energy that only increases the entropy of the universe (Very rapidly!), but it is still energy being added to the universe. 

"Empty Space"  is NOT "nothing"--- it most certainly IS a something, with a computable energy value.

[Putnam]

The vacuum catastrophe is a thing.

There is energy in any given space, though, regardless of smallness, that much is very true.

[Cryxis, Prince of Doom]

Huh

What if we went bigger and added a quarter of the sins mass worth of iron


Let's not forget the impact of these two objects, one the size of Saturn and the other a quarter of the sun, I would love to know how objects this size slowly impacting the sun would affect it.
I think the quarter the mass one might have enough energy to just throw a good chunk of mass out into space upon impact





((Note my astronomy education may be off but isn't iron the death of a star? As in when a star begins producing it as it's next major byproduct ((as in no other atoms of x element left so now it fuses one higher up as it's major fuel source)). Even what I've seen on science Chanel said once a star begins producing large quantities of iron that it die because stars can fuse iron without collapsing in on themselves.))

[hops]

What would be the mass of iron required to cause something interesting to the sun?

I totally don't have a giant intergalactic buccaneer cannon.

[Putnam]

It's not iron that causes stellar death, it's the lack of everything else.

[Cryxis, Prince of Doom]

Ah
So it can produce iron and further but once it doesn't have enough other lower things it doesn't have the energy to do anything with it then?

[Putnam]

No, the main problem is that the energy output by the star can no longer overcome gravity. That's what causes a type II supernova.

[wierd]

More or less right....


Energy is released, which helps keep the star "inflated", when fusion reactions with elements lighter than iron are undergone, and energy is released when elements heavier than iron decay through fission reactions. 

Stars are powered by fusion, so when iron gets made, fusing it into something heavier consumes energy, rather than liberating it.

The force pushing the star together, and thus driving the fusion, is gravity.  Gravity is associated with the gravitational attractive force of a quanta of matter in a quanta of space.  Adding mass to the star will increase its gravitation, which will increase the rate of fusion reactions.

Bigger stars have more mass, so their cores get squeezed harder by gravity.  This squeezing allows (rather, forces) them to produce elements heavier than iron in their cores. However, this means that the energy stored in their outer layers gets gobbled up, just keeping the star inflated.  Really large stars dont live as long as a consequence.

[Descan]

I don't believe that a 1.25 solar mass star is still large enough to fuse iron, so I think that's still out.

As for the impact itself, depending on how slowly it is going... Well, the sun is a plasma. It's not solid. So there's not going to be an impact. It'll have a displacement, and how much is displaced depends on how fast it's going? You could probably end up with a normal (ish) star at the end, maybe with a slight aura of hydrogen that got blasted out far enough to escape the corona? I'm not sure on this area.

Of course, it'd be a star with an iron core. It'd still have the same amount of hydrogen fuel, of course. But, well, not all the hydrogen in stars is used up from birth to death, that's fairly obvious, or else we'd have no hydrogen left by now, there's actually loads of the stuff around still. I think the sun is a second or third generation star.

I don't think a star with an iron core of 25%, even if it still has the same hydrogen content as the sun, is going to last much longer. Most hydrogen fusion occurs in the core, and since iron is heavier than hydrogen, it'll probably sink to become the core eventually, displacing the main area of fusion.

[hops]

So shooting a world-sized cannonball at it won't affect it?
Awwww.

[Cryxis, Prince of Doom]

And a slightly out of the box question
Is the energy of a supernova enough to fuse extremely heavy elements, or are our heaviest elements produced prior to a supernova?

[Descan]

Nah, most elements beyond iron come predominantly from (relatively) instant fusion in supernovae.