Space and the Universe

[Supergrunch]

Becaus that's how our brain works, and everything we encounter is.

Yeah, but our brain evolved to make sense of the world around us, which is very much macroscopic. You get the same thing at the other end of the spectrum - people can't really comprehend the difference between a million and a billion, let alone larger numbers, and ironically this is one of the reasons that some people find it difficult to come to terms with the vast stretches of time necessary to make sense of evolution. And we can't visualise e.g. 4-dimensional systems, etc. for similar reasons. But that doesn't mean we can't employ deduction and experiment in totally unfamiliar domains of course, and that's why you end up with seemingly crazy things like quantum physics, which are nonetheless predictively brilliant.

[MadDog]

What books would you guys recommend? Something abit more basic though than Quantum Physics, though. :p

[MoogleViper]

Yeah, but our brain evolved to make sense of the world around us, which is very much macroscopic. You get the same thing at the other end of the spectrum - people can't really comprehend the difference between a million and a billion, let alone larger numbers, and ironically this is one of the reasons that some people find it difficult to come to terms with the vast stretches of time necessary to make sense of evolution. And we can't visualise e.g. 4-dimensional systems, etc. for similar reasons. But that doesn't mean we can't employ deduction and experiment in totally unfamiliar domains of course, and that's why you end up with seemingly crazy things like quantum physics, which are nonetheless predictively brilliant.

 

That's what I meant, but in less words.

[Supergrunch]

That's what I meant, but in less words.

Oh fair enough, I thought you meant everything we encounter even in other areas of science is intuitive.

[Gizmo]

When he started explaining the strange behaviour of light in the slit experiment, about how it takes all possible paths or something to that effect. I started obsessing with trying to understand it and never really got further. I want to give it a shot again, but I rarely sit down and read at the moment.

 

Quantum Physics is pretty mind blowing. The slit experiment is essentially proof that the electron acts like a wave, as the interference pattern observed for electrons passing through is exactly the same as for light when one hole is open AND when two are open. This implies that the electrons, even when going through one at a time, have some kind of knowledge of what has gone through before them, as the interference effect is present when the result is observed. To explain that, we say that the electrons path is not set until the observation is made - they take every possible path. Then when we look at the screen, we "collapse the wave function", ie the paths of each electron are determined from the infinitely many possiblities to be one particular path and the interference effect therefore comes into play between each one. This is the "Copenhagen Interpretation" because it was Niels Bohr that came up with it.

 

Dunno if thats exactly what you were referring to, but regardless its a nice example of how awesome Quantum Theory is. Anyone looking for a good introductory book on Quantum Physics, I'd recommend "In Search of Schroedingers Cat" by John Gribbon. It gives the full history of Quantum Theory, explaining who, how, when and why we came to these ideas, and has a a chapter dedicated to explaining what I just tried to in one paragraph. It's a little maths-y, but you can probably get past that and just enjoy the concepts.

[heroicjanitor]

Well I was recently reading Stephen Hawking's book, The Grand Design. And he describes how gravity allows the appearance of matter from nothing on a global level, but not a local level. This is due to gravity being a negative force and the creation of matter being a positive force.

 

Anyway, it all sounds very good, but I'm not sure I understand it, and was hoping people could help me shed some light on it.

 

God did it.

 

Makes me miss quantum mechanics/physics in general when I read stuff like that though.

[Gizmo]

Relevant:

 

[Dannyboy-the-Dane]

Quantum Physics is pretty mind blowing. The slit experiment is essentially proof that the electron acts like a wave, as the interference pattern observed for electrons passing through is exactly the same as for light when one hole is open AND when two are open. This implies that the electrons, even when going through one at a time, have some kind of knowledge of what has gone through before them, as the interference effect is present when the result is observed. To explain that, we say that the electrons path is not set until the observation is made - they take every possible path. Then when we look at the screen, we "collapse the wave function", ie the paths of each electron are determined from the infinitely many possiblities to be one particular path and the interference effect therefore comes into play between each one. This is the "Copenhagen Interpretation" because it was Niels Bohr that came up with it.

 

Dunno if thats exactly what you were referring to, but regardless its a nice example of how awesome Quantum Theory is. Anyone looking for a good introductory book on Quantum Physics, I'd recommend "In Search of Schroedingers Cat" by John Gribbon. It gives the full history of Quantum Theory, explaining who, how, when and why we came to these ideas, and has a a chapter dedicated to explaining what I just tried to in one paragraph. It's a little maths-y, but you can probably get past that and just enjoy the concepts.

 

Right. Thanks. I'd actually understood pretty much all of that. It was when he tried explaining the "takes all possible paths" thing that my very tired mind gave up.

[Dog-amoto]

Won't be seen again till 2117. Starts just after 11 apparently.

 

Enjoy!

 

[gaggle64]

This may have been posted in here already but I've only just found it so here it is anyway: A time lapse view of the Earth at night from the ISS.

Full screen this mother. It's incredible.

 

[Retro_Link]

Are people aware of this...

 

 

 

Fucking terrifying!... Especially the part where he didn't know whether he was just stuck in Space!!!!!!

 

And this Summer this guy Felix Baumgartner is gonna try and break his record!... Kittinger is the mentor speaking in the video.

 

Edited June 16, 2012 by Retro_Link

[Ville]

This thread is awesome...

[Jonnas]

I really should visit this thread more often. That quantum physics conversation...is the "every path possible" business related to Schrödinger's Cat?

[BowserBasher]

Came here from a post by Retro_Link in the Awesome stuff thread. This thread is brilliant. Just watched the Time Lapse video from a few posts up and have to say that is amazing. What I love the most is seeing all the lightning storms. Just wonderful

[Diageo]

I really should visit this thread more often. That quantum physics conversation...is the "every path possible" business related to Schrödinger's Cat?

 

Schrodinger's Cat is used to explain Superposition. Which is that quantum particles are in every state possible. It sounds similar to the every possible path business but appears to be different as well.

 

Reference

[Mokong]

Schrodinger's Cat is used to explain Superposition. Which is that quantum particles are in every state possible. It sounds similar to the every possible path business but appears to be different as well.

 

Reference

 

Cheers for the video link, enjoyed that, going through other vids from that channel now

[Cube]

The Schrodinger's cat paradox outlines a situation in which a cat in a box must be considered, for all intents and purposes, simultaneously alive and dead. Schrodinger created this paradox as a justification for killing cats.

[Dannyboy-the-Dane]

That series you linked to is great. I highly recommend it.

 

One thing has always bugged me about Schrödinger's Cat, though, and that's the use of a cat as the test subject; doesn't the cat count as an observer as well? Shouldn't it automatically collapse the superposition simply by being aware?

Edited June 18, 2012 by Dannyboy-the-Dane

[Cube]

One thing has always bugged me about Schrödinger's Cat, though, and that's the use of a cat as the test subject; doesn't the cat count as an observer as well? Shouldn't it automatically collapse the superposition simply by being aware?

 

It's both alive and dead to the universe outside the box, not inside the box.

[Magnus]

The Schrodinger's cat paradox outlines a situation in which a cat in a box must be considered, for all intents and purposes, simultaneously alive and dead. Schrodinger created this paradox as a justification for killing cats.

Schrödinger's cat: also known as Jones's baby.

[Dannyboy-the-Dane]

It's both alive and dead to the universe outside the box, not inside the box.

 

Aaand now I'm lost again.

[Cube]

Aaand now I'm lost again.

 

The whole point is that the observers (outside the box) have no idea about the condition of the cat (inside the box) - weather the cat is aware or not is irrelevant (it wouldn't even matter if it was a human inside the box).

[Diageo]

Exactly as Cube said. It's a way of showing something is either alive or dead. You could use an automatic coin flipper instead of the decaying isotope. The cat is both alive and dead, and you don't know until you open the box, which is a metaphor for any observation. The cat of course knows if he is dead or alive, but the point is that we don't.

[Dannyboy-the-Dane]

But I thought the point was that until an observation is made, both states exist simultaneously? What you're describing sounds like standard logic - we don't know what state it's in until we've observed it.

[Ganepark32]

To be honest, the Schroedinger's cat thing is a bit of a moot point anyway. We'd hear the cat in the box meowing or scratching about inside so we would know it's alive rather than it being in a state of superposition :p