James Webb Telescope

[rjh01]

No, i meant fission. The process of fission (not fusion) results in the formation of elements including plutonium, xenon, strontium, ceasium and others. The man-made transuranic elements are the result of fission reactions.

Let us get the definitions right
Fission

1: a splitting or breaking up into parts
2: reproduction by spontaneous division of the body into two or more parts each of which grows into a complete organism
3: the splitting of an atomic nucleus resulting in the release of large amounts of energy

Fusion

: the union of atomic nuclei to form heavier nuclei resulting in the release of enormous quantities of energy when certain light elements unite

 

[RecoveringYuppy]

No, i meant fission. The process of fission (not fusion) results in the formation of elements including plutonium, xenon, strontium, ceasium and others. The man-made transuranic elements are the result of fission reactions.

Those are produced by neutron capture, not fission. Neutron capture isn't fission It is a side effect of the neutrons produced by fission but it itself is essentially fusion in the sense that two things are merging, not splitting. Neutron capture raises the mass of the nucleus so it's closer to fusion than fission. It's essentially fusion but the word fusion is normally reserved for the harder process of merging charged nuclei.

 

[Ziggurat]

Those are produced by neutron capture, not fission. Neutron capture isn't fission It is a side effect of the neutrons produced by fission

I suspect that's where the misunderstanding comes from: plutonium and some other heavy elements are created in nuclear reactors, nuclear reactors run on fission, so it's not unreasonable to conclude that fission is creating these heavy elements.

Not unreasonable, but still wrong.

 

[The Great Zaganza]

The naming of the Telescope is becoming more and more controversial.
Soon, NASA will have no choice but to self -destruct this one and send out an another with a different name.

 

[RecoveringYuppy]

I suspect that's where the misunderstanding comes from: plutonium and some other heavy elements are created in nuclear reactors, nuclear reactors run on fission, so it's not unreasonable to conclude that fission is creating these heavy elements.

Not unreasonable, but still wrong.

Yes, perfectly reasonable.

I note that one detail got missed though: acbytesla's list of elements aren't all neutron capture. Some are actual fission products.

 

[acbytesla]

Let us get the definitions right
Fission

Fusion

I knew this. Another diffeeence is that fission reactors are real and have been generating power since the 1950s. Fusion reactors are mostly a fantasy.

 

[acbytesla]

Those are produced by neutron capture, not fission. Neutron capture isn't fission It is a side effect of the neutrons produced by fission but it itself is essentially fusion in the sense that two things are merging, not splitting. Neutron capture raises the mass of the nucleus so it's closer to fusion than fission. It's essentially fusion but the word fusion is normally reserved for the harder process of merging charged nuclei.

Yes you are right. But fission reactions are started by bombarding fissile materia with neutrons; Uranium 235, Thorium 233, Plutonium 239.

 

[RecoveringYuppy]

Yes you are right. But fission reactions are started by bombarding fissile materia with neutrons; Uranium 235, Thorium 233, Plutonium 239.

True but not sure how that is relevant to the point.

To get back to to the point, we were discussing whether we understood the physics that occurred prior to the decoupling. The extreme neutron capture reactions we are discussing now aren't relevant. Those started happening well after the decoupling. The only fusion/capture reactions that were relevant before the decoupling were those involved hydrogen, helium, and lithium. Those are well understood (not to imply that the others aren't well understood also).

 

[acbytesla]

True but not sure how that is relevant to the point.

To get back to to the point, we were discussing whether we understood the physics that occurred prior to the decoupling. The extreme neutron capture reactions we are discussing now aren't relevant. Those started happening well after the decoupling. The only fusion/capture reactions that were relevant before the decoupling were those involved hydrogen, helium, and lithium. Those are well understood (not to imply that the others aren't well understood also).

Yes, my point was that man made fusion is essentially not real. Yes there have been fusion reactions in science experiments mostly lasting fractions of a second.

The idea that most of the elements in the periodic table are created in stars is only demonstrated through telescopic spectroscopy.

 

[RecoveringYuppy]

Yes, my point was that man made fusion is essentially not real. Yes there have been fusion reactions in science experiments mostly lasting fractions of a second.

The idea that most of the elements in the periodic table are created in stars is only demonstrated through telescopic spectroscopy.

No. Those reactions have been confirmed in accelerators, reactors, and hydrogen bombs. Why do you dismiss those? The reactions happen in fractions of a second in stars too.

And, again, you're now talking about things that happen after the decoupling.

 

[acbytesla]

No. Those reactions have been confirmed in accelerators, reactors, and hydrogen bombs. Why do you dismiss those? The reactions happen in fractions of a second in stars too.

And, again, you're now talking about things that happen after the decoupling.

You'll have to forgive me.

I understand that certain elements are the result of fission, neutron capture as well as radioactive decay. I also have been under the impression that much of (I thought most) were created in stars or from exploding and colliding stars.

I get that the science behind the theory of element creation is also considered mostly settled. Still, it seems as if it is difficult to prove the star manufacture hypothesis practically.

 

[RecoveringYuppy]

I understand that certain elements are the result of fission, neutron capture as well as radioactive decay. I also have been under the impression that much of (I thought most) were created in stars or from exploding and colliding stars.

This is correct. Do you think I contradicted this somewhere?

I get that the science behind the theory of element creation is also considered mostly settled. Still, it seems as if it is difficult to prove the star manufacture hypothesis practically.

OK. You can choose your own level of proof. But most scientists would consider that the higher elements beyond lithium and a tiny amount of boron to have been created post decoupling. How they get produced later is still under study but the "later" part is not at issue.

BTW it's not just stars and supernovas. Some elements involve other processes like neutron star collisions.

 

[acbytesla]

BTW it's not just stars and supernovas. Some elements involve other processes like neutron star collisions.

Maybe I'm just dense. But isn't a neutron star a star? Dead star to be more precise? It seems to me I read an article about the observation of two neutron stars colliding a few years ago. And that the spectroscopy of that collision left laege signatures of many elements including gold.

 

[RecoveringYuppy]

Maybe I'm just dense. But isn't a neutron star a star? Dead star to be more precise?

Sure, either one I suppose.

It seems to me I read an article about the observation of two neutron stars colliding a few years ago. And that the spectroscopy of that collision left laege signatures of many elements including gold.

Yep. That's what I was referring to.

 

[acbytesla]

Sure, either one I suppose.


Yep. That's what I was referring to.

This is fascinating.


In all honesty, I'm just learning a lot of this.

And as much as I'm interested in the story of how the universe and the elements were formed, I'm even more interested in how science came to those conclusions. I'd like to know more for practical reasons.

It seems more than bizarre to me that astrophysicists can confidently date the age of the universe. Or how they can claim that elements like hydrogen, helium and lithium were made in the first few seconds. Or that all the matter and energy was concentrated in a very tiny area and expanded to 90 plus billion light year size.

On one hand I've read that nothing can travel faster than the speed of light yet I've also read that galaxies are traveling away from us faster than light. I swear, the more I learn about all this the crazier it seems. I'm reminded of Richard Feynman saying that the universe is weirder than you can possibly imagine.

I'm wondering if the JWST and its capabilities will confirm or change what we believe we know.

BTW: I just read that the MIRIcam is down to 17 degrees Kelvin and when it reaches 15 degrees, they will make an adjustment to the cryocooler to push the temperature to the required 7 degrees.

 

[ynot]

I'm wondering if the JWST and its capabilities will confirm or change what we believe we know.

I'm hoping more for "change".

 

[acbytesla]

I'm hoping more for "change".

Me too. But I'm not sure why I'm hoping for that.

 

[ynot]

Me too. But I'm not sure why I'm hoping for that.

Perhaps, like myself, you're not completely comfortable with everything what we believe we know.

 

[arthwollipot]

I knew this. Another diffeeence is that fission reactors are real and have been generating power since the 1950s. Fusion reactors are mostly a fantasy.

Self-sustaining fusion reactors are creeping closer all the time. 10 years ago, fusion reactors were in the "40 years away, and always will be" category. Now they're "5-10 years".

 

[acbytesla]

Self-sustaining fusion reactors are creeping closer all the time. 10 years ago, fusion reactors were in the "40 years away, and always will be" category. Now they're "5-10 years".

No they're not. They're nowhere near that close. I'd be shocked beyond belief that a power generating fusion reactor is operating in the next 40 years. I keep reading about breakthroughs in fusion lately. But under close examination these so called breakthroughs while interesting, they hardly have advanced the science to the point where a cost effective power producing nuclear fusion reactor.

They are closing in on .75 Q. Q is the break even point where more energy is put into a fusion reaction. But this number is deceiving as hell because it only includes power into the reaction, not the power required to contain the reaction. And these reactions are under a second.

For a fusion reactor to be real, they will need it to run 24x7 365 days a year or at least close to that number. The material science alone for such a reactor is decades away. And that's just the start of the problems.

I think the science is fascinating, but I also think people are swallowing snake-oil on fusion at this time.