How will the universe end?

[Yellow Fang]

Another problem with the Big Bang theory is that it predicts protons are unstable. They should have a half life of a thousand billion billion billion years, but apparently they are more stable than that.

 

[Solocle]

This is what puzzles me. I read that Hawking Radiation occurred when a matter/anti-matter pair of particles spontaneously appeared just outside the event horizon of the black hole. The anti-matter particle would fall into the black hole and annihilate a bit of its mass. The matter particle would escape as Hawking Radiation. But matter particles have mass. However googling Hawking Radiation, it says it's electromagnetic radiation or blackbody radiation, which are photons. I am sure there is an explanation.



I only heard this one a couple of days ago. I wonder whether this expansion factor, Einstein's frig factor, causes everything to spread out or just space to spread out. If it caused everything to spread out, then the electrical, weak nuclear and strong nuclear forces are only powerful over small distances.

Hawking radiation is a good deal more complex than that. It depends on wave-particle duality in Quantum physics - the vacuum has random oscillations of quantum fields, due to Heisenberg's uncertainty principle. However, near a black hole, some of these oscillations cross the event horizon, so a distant observer sees the emission of radiation - however, a free-falling observer in the vicinity of the black hole does not - so it's not a question of particles popping into existence, it's far more weird than that.

This is similar to the Unruh effect, where an accelerating observer forms an event horizon - because, if they kept accelerating, the light from behind the horizon would never reach them. An observer accelerating away from the black hole (staying stationary above the event horizon) gets Hawking radiation as a consequence of this effect.

 

[marinyork]

Now I am not sure whether he said there was too much helium and lithium compared to theoretical predictions or not enough. Theory predicted very small amounts of lithium. I have sometimes wondered why there is not more lithium. It would be pretty handy now.

There is more helium-4 than some models predict.

Helium-4 is not particularly intuitive as it behaves very different in extreme conditions.

In the past there were questions about how stars produce helium and so on. It wasn't understood better until quantum tunneling was applied and cross sections rigorously understood even though those two ideas were flagged up a very surprisingly long time ago and still not really popularised with the public.

 

[Moon bunny]

I have got a new cat.

 

[Speicher]

I have got a new cat.

Is it one from next door?

 

[Moon bunny]

No, it is a kitten I was promised some time ago, because Sammy is growing ancient in years. This is now a 4 cat and 1 dog household, luckily it is a big house.

 

[cyberknight]

42

if it hasnt already been stated as i CBA to read the whole thread, a restaurant

 

[Profpointy]

Excellent point. We can't measure far enough but I must dispute the idea of a doughnut shape as the Plod would have eaten that by now.


I've just Skyped with Prof Penrose and I realise now where he has gone wrong in all of this. He hasn't taken into account physics beyond the standard model of particle physics nor the new physics of the cosmos beyond the LamdaCDM model. I don't blame him for that as he doesn't have a time machine like wot I do. So I must now revert to the present Hawking radiation model as of now, not the future upgraded one I was referring to. Mustn't mess with the time line

He's a smart one that Penrose fellow. He invented a new kind of tile too. I wanted to buy some but special order only it seems

Edit: I should probably clarify that I really did try to search for commercially available Penrose tiles but couldn't find any, though they have been specially made for Physics Departments and the like, and there's a building near the Thames in East London tiled with them. The road was called Penrose Street (or Avenue) so they were clearly honouring Sir Roger

They're quite simple shapes really yet it was an advance in geometry when he described them

https://en.m.wikipedia.org/wiki/Penrose_tiling

 

[Yellow Fang]

I have got a new cat.

Is it alive, dead or both?

 

[Moon bunny]

Very much alive.
Signed
Moon bunny, the thread diversion champion

 

[Yellow Fang]

42

I wonder about this. 42 seems like too big a number and its an integer. If it was an integer you'd expect it to be at least in single figures. I would have thought an irrational number like e or pi would be more likely, although it would be disappointing if it was e or pi. Also the answer 42 has no units. If the answer was something like 42.0023 J/m.K.s^2 that would give scientists something to go on. For Deep Thought to have found the answer 42, but not know the question, that probably means it examined everything it could find in the universe and kept finding the number 42 buried in its structures. So far as I know, 42 does not appear anywhere particularly much. Also if the number 42 did keep cropping up in important ways, the obvious question would be why. You wouldn't need to build an even bigger computer to formulate the question.

 

[Andy_R]

I have got a new cat.

I think the universe will end when we run out of cat videos on Youtube. You know the ones I mean....cat's being barstewards, cats being scared of cucumbers, cats being barstewards again, cats jumping off furniture and missing....the list is endless...

 

[Landsurfer]

I wonder about this. 42 seems like too big a number and its an integer. If it was an integer you'd expect it to be at least in single figures. I would have thought an irrational number like e or pi would be more likely, although it would be disappointing if it was e or pi. Also the answer 42 has no units. If the answer was something like 42.0023 J/m.K.s^2 that would give scientists something to go on. For Deep Thought to have found the answer 42, but not know the question, that probably means it examined everything it could find in the universe and kept finding the number 42 buried in its structures. So far as I know, 42 does not appear anywhere particularly much. Also if the number 42 did keep cropping up in important ways, the obvious question would be why. You wouldn't need to build an even bigger computer to formulate the question.

42 ... was the Hubble Constant ... the rate of expansion of the universe .... which Douglas Adams used as his answer .....
However .. after the Hubble Telescope was upgraded by Nasa etc it was discovered that the constant was actually ............ drum roll ...........

43 ...!!!

 

[Yellow Fang]

42 ... was the Hubble Constant ... the rate of expansion of the universe .... which Douglas Adams used as his answer .....
However .. after the Hubble Telescope was upgraded by Nasa etc it was discovered that the constant was actually ............ drum roll ...........

43 ...!!!

Really?!

 

[Ming the Merciless]

I have got a new cat.

Called Shrodinger?