Science questions not worth a thread I: I'm a moron!

[uppi]

Redshift changes the energy per unit of time, but not the total energy. A single photon from a star coming towards us will be 'blue shifted', but it can contain the same energy as a single photon from a star receding from us. It will take longer for the red-shifted photon to transfer all of its energy than the blue-shifted photon, but if they were equivalent photons when they were created, then their total energy will be the same at the end.

No, that's the wrong explanation. The time it takes for a photon to transfer its energy is independent of its (center) frequency, but depends on the envelope of a photon. You can reshape the blue-shifted photon so that it takes forever to transfer its energy without changing its energy. The bandwidth of a photon is related to the time it takes to transfer its energy and not the energy itself.

Energy is not invariant during a Lorentz transformation. This should become obvious very quickly: An object at rest has no kinetic energy. But if you look at it in a reference frame that is moving relative to it, the object suddenly has kinetic energy. So the answer to the question is, that you are comparing apples to oranges as the energy in the reference frame where the emitter is at rest is something different than the energy in the reference frame where the absorber is at rest. So to convert the energy from one frame to the other you would need to make a Lorentz transformation, which then would give you the energy of the red-shifted photon.

 

[Power_of_Beer]

nvm, thanks uppi.

 

[PlutonianEmpire]

I think I recall earlier in this thread, someone (probably me) mentioned recycling absolutely everything, and someone countered that it would use more energy and resources than it would give back, and ruin the environment, and such.

My question is, might it be possible, eventually, given enough time for technological advancement, with new technologies, recycling absolutely everything might become easier and less energy/resource and fewer consequences to the environment?

 

[Cutlass]

I doubt we'd ever reach the point of recycling everything. But efficiency would improve over time. If you had a closed environment like a space habitat, you would have to have very high levels of recycling. But I don't know how you would get down to no loss.

 

[El_Machinae]

I think I recall earlier in this thread, someone (probably me) mentioned recycling absolutely everything, and someone countered that it would use more energy and resources than it would give back, and ruin the environment, and such.

My question is, might it be possible, eventually, given enough time for technological advancement, with new technologies, recycling absolutely everything might become easier and less energy/resource and fewer consequences to the environment?

This is the thesis of the book Cradle to Cradle. The idea was to design products such that they can be recycled. Right now, no one upstream in the design process really cares about taking apart the used item. Entrepreneurs that are downstream care about recycling, but they're limited by the way we make products that become trash.

It's a very excellent book

 

[emzie]

I think I recall earlier in this thread, someone (probably me) mentioned recycling absolutely everything, and someone countered that it would use more energy and resources than it would give back, and ruin the environment, and such.

My question is, might it be possible, eventually, given enough time for technological advancement, with new technologies, recycling absolutely everything might become easier and less energy/resource and fewer consequences to the environment?

There are things that are more energy intensive to recycle than to make new. I think it's more likely we'll replace paper than that we'd find a way to make recycling it worthwhile.

I doubt we'd ever reach the point of recycling everything. But efficiency would improve over time. If you had a closed environment like a space habitat, you would have to have very high levels of recycling. But I don't know how you would get down to no loss.

In a closed system, it'd be impossible to get it down to no loss.

 

[madviking]

This is the thesis of the book Cradle to Cradle. The idea was to design products such that they can be recycled. Right now, no one upstream in the design process really cares about taking apart the used item. Entrepreneurs that are downstream care about recycling, but they're limited by the way we make products that become trash.

It's a very excellent book

Not recycling, per se. The authors refer to conventional recycling as "downcycling". They introduce the idea of "upcycling", which products gain more and more utility as they are reused.

 

[Birdjaguar]

Not a question, but a cool link:

http://dk.filmomania.pl/j/Scale_of_Universe_In93570.swf

Use the blue slider at the bottom to move around.

 

[Gatsby]

Hi, I have a question about fusion power.

Would it be possible to trigger a sustained reaction in a fusion reactor by harnessing the power of lightning from thunderstorms?

Lightning bolts have an enormous amount of energy, but it is very difficult to store such a vast amount of energy. Commercial-scale fusion reactions require vast amounts of energy to initiate, and I am not aware of any experimental fusion reactor that has yet been able to produce more energy than it consumes.

I don’t know much at all about physics, but I wonder if these two power sources could be combined in such a way that they cancel out each other’s major disadvantages: the problem of storing lightning energy would be negated because it’s energy is used up by initiating the fusion reaction, while the problem of net energy loss from the fusion reaction is made irrelevant because the fusion reactor would effectively become a machine which harnesses the ‘free’ energy of lightning by converting the lightning’s energy into a sustained fusion reaction (with only part of the lightning's energy being lost in the conversion process).

 

[PlutonianEmpire]

I'm seeing some news sites claiming the discovery of a new "earthlike" planet, but really they're just bringing back Gliese 581g from last year. Does this mean 581g has been confirmed, or are they just rumors because they're bored due to this being a slow news week?

 

[IdiotsOpposite]

Hi, I have a question about fusion power.

Would it be possible to trigger a sustained reaction in a fusion reactor by harnessing the power of lightning from thunderstorms?

Lightning bolts have an enormous amount of energy, but it is very difficult to store such a vast amount of energy. Commercial-scale fusion reactions require vast amounts of energy to initiate, and I am not aware of any experimental fusion reactor that has yet been able to produce more energy than it consumes.

I don’t know much at all about physics, but I wonder if these two power sources could be combined in such a way that they cancel out each other’s major disadvantages: the problem of storing lightning energy would be negated because it’s energy is used up by initiating the fusion reaction, while the problem of net energy loss from the fusion reaction is made irrelevant because the fusion reactor would effectively become a machine which harnesses the ‘free’ energy of lightning by converting the lightning’s energy into a sustained fusion reaction (with only part of the lightning's energy being lost in the conversion process).

From what I remember, the problem with a sustained fusion reaction isn't that it takes a lot of energy to start it; rather, that's actually kind of easy. The real problem is that the temperature of the fusing material is so high that we don't currently have any methods to perfectly contain it, and without containment we'd have a much bigger problem on our hands.

But I'm probably wrong.

 

[bonefang]

Not a question, but a cool link:

http://dk.filmomania.pl/j/Scale_of_Universe_In93570.swf

Use the blue slider at the bottom to move around.

Thanks ... its awesome !!

 

[dutchfire]

From what I remember, the problem with a sustained fusion reaction isn't that it takes a lot of energy to start it; rather, that's actually kind of easy. The real problem is that the temperature of the fusing material is so high that we don't currently have any methods to perfectly contain it, and without containment we'd have a much bigger problem on our hands.

But I'm probably wrong.

Yeah, the start up energy is high but that is not really a problem. The main problem is to sustain a long fusion reaction.

 

[emzie]

Yeah, the start up energy is high but that is not really a problem. The main problem is to sustain a long fusion reaction.

Indeed, artificial fusion power has been available to humans since the 50s. It's just rather destructive in that form.

 

[r_rolo1]

Yeah, the start up energy is high but that is not really a problem. The main problem is to sustain a long fusion reaction.

Better said, it is hard keeping a fusion reaction that:

1) Does not die fast because of excessive energy leakage out of the system ( we want some energy leakage, otherwise it would be useless as a energy producer reactor )

2) Does not go out of control ( Beneath the Planet of Apes style finale )

Stars do both by "use" of gravity and a massive mass surplus ( that both avoids that most of the energy leaks out directly ( except neutrinos ) and contains the nuclear reaction to the star core ). Doing that in a more human scale ... well,we had more progress in containing the reaction than in keeping it running without major leakage.

 

[Quackers]

If the recent frenzy around the faster-than-the-speed-of-light neutrinos are true what are the implications for physics? Anything significant?

EDIT: Got another one. Which types of fat are "ok" (in relations to other fats) and which are NO GO. I believed saturated fat was bad but then trans fats came along or is that the same thing? derp

 

[emzie]

EDIT: Got another one. Which types of fat are "ok" (in relations to other fats) and which are NO GO.

That's hard to quantify, since too much of "good" fats would still be very bad, and a small mount of "bad" fats isn't going to have an adverse effect on you.

Aside from weight gain, fats are generally divided into good / bad based on what they do to one's cholesterol count. That's a bit simplistic a view of health. Aside from the fact that cholesterol is absolutely vital to you, bad / good ratios are generally a reflection of your health -- like a runny nose is an indication of a viral infection -- not a cause of bad health in the first place. That is, if you have high "bad" cholesterol, you're unhealthy in other ways, and merely lowing your "bad" cholesterol isn't going to do you any good without other changes like weight loss.

I believed saturated fat was bad but then trans fats came along or is that the same thing? derp

They're different. You can eat some saturated fat without adversely impacting your health. On the other hand, trans fats are just all around bad for you, though the trace amounts you get from eating meat / dairy isn't going to kill you.

 

[uppi]

If the recent frenzy around the faster-than-the-speed-of-light neutrinos are true what are the implications for physics? Anything significant?

First, we would have to rethink relativity. It cannot be totally wrong, as it has been validated by many other experiments (and this neutrino experiment uses relativity to measure their result), but we would need to find a way to fit superluminal neutrinos in there. This could be done by giving neutrinos an imaginary mass, as neutrino oscillations have shown that there is a mass difference between neutrino flavors, but not that their mass has to be real. But what an imaginary mass is and how to integrate such particles with the rest of physics would be questions that gave theorists a lot of work to do.

Second, it has been shown, that superluminal neutrinos would lose energy by bremsstrahlung emission of electron-positron pairs. However, this energy loss has not been observed. So either neutrino are not really faster than light, or our understanding of the weak interaction is wrong. This would scratch at another foundation of modern high energy physics.

If the measurement of superluminal neutrinos is confirmed, it has the potential to be a major upheaval of our current theories.

 

[ParadigmShifter]

Ah, the bremsstrahlung emission of electron-positron pairs. I knew it had to be something to do with that!

 

[Silurian]

Well could be

http://en.wikipedia.org/wiki/Bremsstrahlung