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Neil deGrasse Tyson AMA

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Re: Neil deGrasse Tyson AMA

#11

Post by Herring »

jessriedel wrote: post #7
Herring wrote: post #4

Earlier quoted context omitted.

re electron: It's probably more accurate to say "size" has no meaning at that scale. Particles turn into waves, spacetime isn't smooth, etc.

>It's probably more accurate to say "size" has no meaning at that scale Not at all. Size has unambiguous meaning down to the Planck scale (10^-35 meters) and electrons simply haven't been probed at scales smaller than 10^-22 meters. They could very well have heretofore-undetected structure (e.g. preon models) on the scales of 10^-20 while still have fifteen orders of magnitude (about the relative span between an atom…

Size of what, then? Its not a particle. Having internal structure doesn't mean volume makes sense. You're right that distances do make sense, and he probably meant the electron has no known internal structure. But I don't know how you'd talk about size unless you mean a zone of probability of where it is.

Re: Neil deGrasse Tyson AMA

#12

Post by fragsworth »

tkahn6 wrote: post #8
jphackworth wrote: post #2

Really interesting. A couple of physics things I did not know that Neil mentions: 1) The fact that an electron has no known size -- it's smaller than the smallest measurement we have ever made of anything. 2) That Quarks come only in pairs: If you try to separate two of them, the energy you sink into the system to accomplish this feat is exactly the energy to spontaneously create two more quarks - one to partner with…

See also: Q: Since time slows relative to the speed of light, does this mean that photons are essentially not moving through time at all? A: yes. Precisely. Which means ----- are you seated? Photons have no ticking time at all, which means, as far as they are concerned, they are absorbed the instant they are emitted, even if the distance traveled is across the universe itself.

And we, as humans, are emitting photons right now. Little pieces of us are right now instantly traveling across the universe and colliding with other stars, planets, etc., or flying through the void - instantly - to who knows where?

Re: Neil deGrasse Tyson AMA

#13

Post by nobody3141592 »

Herring wrote: post #11
jessriedel wrote: post #7

Earlier quoted context omitted.

>It's probably more accurate to say "size" has no meaning at that scale Not at all. Size has unambiguous meaning down to the Planck scale (10^-35 meters) and electrons simply haven't been probed at scales smaller than 10^-22 meters. They could very well have heretofore-undetected structure (e.g. preon models) on the scales of 10^-20 while still have fifteen orders of magnitude (about the relative span between an atom…

Size of what, then? Its not a particle. Having internal structure doesn't mean volume makes sense. You're right that distances do make sense, and he probably meant the electron has no known internal structure. But I don't know how you'd talk about size unless you mean a zone of probability of where it is.

It is a particle, just because it has a wavelength doesn't mean it's not a particle.

An elephant has a wavelength it's just that it's rather small compared to the elephant

Re: Neil deGrasse Tyson AMA

#15

Post by jessriedel »

Herring wrote: post #11
jessriedel wrote: post #7

Earlier quoted context omitted.

>It's probably more accurate to say "size" has no meaning at that scale Not at all. Size has unambiguous meaning down to the Planck scale (10^-35 meters) and electrons simply haven't been probed at scales smaller than 10^-22 meters. They could very well have heretofore-undetected structure (e.g. preon models) on the scales of 10^-20 while still have fifteen orders of magnitude (about the relative span between an atom…

Size of what, then? Its not a particle. Having internal structure doesn't mean volume makes sense. You're right that distances do make sense, and he probably meant the electron has no known internal structure. But I don't know how you'd talk about size unless you mean a zone of probability of where it is.

It is a particle. With a wavefunction. HN isn't the best place to teach quantum mechanics, but suffice it to say that the notion of spatial wavefunction spread is completely separate from the idea of particle being point-like vs. having internal structure of significant volume.

Re: Neil deGrasse Tyson AMA

#16

Post by cbo »

akkartik wrote: post #10

So he's skeptical of the singularity but he thinks we'll be able to live forever in a lifetime or so. Weird.

They're two very different ideas, even if they're often shared by the same people.

The singularity is all about AI surpassing human intelligence. On this front, I can tell you after having studied a lot of AI for the past three years, we are not close. We're a lot further than many people think, but still not quite that far.

As for extending lifespans, this is something we've been doing from the dawn of medicine. We've been making significant strides here for thousands of years, and as Aubrey DeGray puts it, we've become very efficient mechanics on the car that is the human body, and we're only getting better at it. There's a lot of research being done on slowing the aging process and beating genetic disorders, which are two of the largest barriers to extremely long lifespans for humans.

Re: Neil deGrasse Tyson AMA

#18

Post by [deleted] »

feralchimp wrote: post #9

So, so many excellent quotes in that discussion. My favorite: "Kids are never the problem. They are born scientists. The problem is always the adults. The beat the curiosity out of the kids. They out-number kids. They vote. They wield resources. That's why my public focus is primarily adults." Preach it, dude.

[deleted]

Re: Neil deGrasse Tyson AMA

#19

Post by tkahn6 »

nobody3141592 wrote: post #13
Herring wrote: post #11

Earlier quoted context omitted.

Size of what, then? Its not a particle. Having internal structure doesn't mean volume makes sense. You're right that distances do make sense, and he probably meant the electron has no known internal structure. But I don't know how you'd talk about size unless you mean a zone of probability of where it is.

It is a particle, just because it has a wavelength doesn't mean it's not a particle. An elephant has a wavelength it's just that it's rather small compared to the elephant

Indeed. See De Broglie's equations.

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

Re: Neil deGrasse Tyson AMA

#20

Post by Dn_Ab »

cbo wrote: post #16
akkartik wrote: post #10

So he's skeptical of the singularity but he thinks we'll be able to live forever in a lifetime or so. Weird.

They're two very different ideas, even if they're often shared by the same people. The singularity is all about AI surpassing human intelligence. On this front, I can tell you after having studied a lot of AI for the past three years, we are not close. We're a lot further than many people think, but still not quite that far. As for extending lifespans, this is something we've been doing from the dawn of medicine. We'…

I agree with your premise. I too am skeptical of a singularity although I am hopeful of at least a Feline level of intelligence within the next decade. But the way these things go, the space of ideas is probably non-euclidean and certainly very high dimensional. It is possible that in the dimensions we are used to looking at things a singularity seems far away but is actually right smack in front of us in another dimension. So I remain agnostic.

Note also that - at least as far as I am aware - we have not managed to extend lifespans. Erastothenes for example lived till 82, at or more than the current expected lifespan of many western and first world countries. We have only increase the probability of arriving near the maximum life span by dealing with famine, war, diseases and optimizing diets and nutrients and lifestyle.

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