14 ms·

Neil deGrasse Tyson AMA

242 points by pbj 15y ago

jphackworth 15y ago
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 each of those you pulled apart.
- pavel_lishin 15y ago
  Huh, I thought Quarks only existed as triplets.
  - jessriedel 15y ago
    They only come in "colorless" sets. The "colors" (which are just suggestive names and have nothing to do with light colors) are Red, Green, and Blue, along with anti-Red, anti-Green, and anti-Blue. Therefore, there are basically two options: mesons, which contain a quark/anti-quark pair (e.g. one Green and one anti-Green) and baryons, which contain quark of each colors (RGB, or antiRGB). Tetraquarks, pentaquarks, and hexaquarks have been searched for in experiment and would not violate the colorless rule, but have never been found. Physicists would prefer to be able to calculate from first principles whether such states are possible, but it turns out that no one knows how to do the calculation because of the non-perturbative nature of the strong force. [Many caveats. For instance, any given hadron (the collective name for things made of quarks, which to date means only mesons and baryons) is not actually made up of quarks with definite color, but rather a quantum superposition of many possibilities. I think mesons, for example, are always a balanced superposition of R-antiR, G-antiG, and B-antiB. So you could never point to a given meson in an experiment and say "that meson was blue-antiblue".]
  - deleted 15y ago
    [deleted]
- Herring 15y ago
  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.
  - jessriedel 15y ago
    >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 and the radius of the earth) over which distances are perfectly sensible. Likewise, before the deep inelastic scattering experiments of the 60's, physicist had no direct evidence that neutrons and protons had any internal structure. All they could say is "we know that if they have internal structure, it's smaller than this length scale". [FYI: The Planck scale is (arguably!) where the notion of size becomes murky because quantum fluctuations in the background spacetime (against which the sizes of things are measured) become substantial. Of course, no one has ever seen (even indirect) evidence of a quantum fluctuation in spacetime. And, as is well known, appling quantum mechanics to gravity and spacetime is full of difficulties. But most physicists believe there are such quantum effects because it seems damn near impossible to reconcile a classical spacetime with quantum everything else.]
    - Herring 15y ago
      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.
      - nobody3141592 15y ago
        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
- tkahn6 15y ago
  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.
  - fragsworth 15y ago
    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?
  - Jach 15y ago
    This answer bothered me. Is he just saying that any supposed delays of "light" we can set up through experiment are really just delays in instantaneous absorption/emission pairs, or is he talking about entangled photons, or some preferred space of simultaneity, or photons not being particles but vectors in a timeless configuration space?
    - galadriel 15y ago
      Most probably he is talking about the fact that proper time for all events in Photon's own frame is zero, i.e. a frame that move with speed of light will notice that all events are instantaneous.
    - teamonkey 15y ago
      I loved this reply. Clarifying and correct, as far as I can tell. http://www.reddit.com/r/IAmA/comments/mateq/i_am_neil_degrasse_tyson_ama/c2zga4o http://www.reddit.com/r/IAmA/comments/mateq/i_am_neil_degras...
  - jahmed 15y ago
    Obligatory xkcd:Prairie http://xkcd.com/967/ http://xkcd.com/967/
  - 15y ago
feralchimp 15y ago
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 15y ago
  [deleted]
- Waxbar1 15y ago
  Interestingly, South Park has been conveying this message message for over 10 years, and I think the generation that grew up watching South Park innately understands this already and at a younger age.
akkartik 15y ago
So he's skeptical of the singularity but he thinks we'll be able to live forever in a lifetime or so. Weird.
- pavel_lishin 15y ago
  Why is that so weird?
- cbo 15y ago
  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.
  - Dn_Ab 15y ago
    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.
    - showerst 15y ago
jrappleye 15y ago
My personal favorite: Q: If you could add one course to a student's curriculum, what would it be?" A: Course title every university should offer: "How to tell when someone else is full of shit"
malkia 15y ago
He is one of my heroes. So charming, funny and educating at the same time. His speech on the islam downfall in the 13th century due to some "prophet" claiming that math and devil were interconnected was much enlightening on how religion actually stops scientific progress.
- kloncks 15y ago
  I was in the middle of one of his talks and heard this exactly. I agree...but allow me to just correct one thing. The "prophet" was a sheikh/imam in Iraq (?) that said math and Satan were connected. Islam had - up until that time - managed to have some pretty amazing feats. That said, it's interesting how we blindly take advice from men with authority. Whether that's religious figures, famous people, or politicians.
  - malkia 15y ago
    Thanks for the correction kloncks! Not trying to excuse myself, but I'm simply not good at remembering details. Would have to watch the video again!
    - kloncks 15y ago
      No worries! It's my view that religion often isn't the thing that impairs scientific learning. Rather it's men's interpretation of those events. Just needed to make that subtle correction :)
      - lukifer 15y ago
        Ideology is a superset of religion, and like fire, it can be used for either creation or destruction.
- omarchowdhury 15y ago
  Does that one instance preclude all of the other people that contributed to science, who also had faith?
davidhollander 15y ago
Anyone interested in NdGT, check out the show he hosts: Nova Science Now http://www.pbs.org/wgbh/nova/sciencenow/ http://www.pbs.org/wgbh/nova/sciencenow/ You can watch full episodes online, no commercial interruptions after they start. It does a good job at filling the popular science video niche, in addition to Through the Wormhole with Morgan Freeman.
- lobster_johnson 15y ago
  I have been looking for a good science show, but Nova scienceNOW wasn't it. Not so much the content as the absolutely juvenline format. Can someone explain how I have misunderstood and the show really is meant for kids? Because it's designed like a kid's show, complete with silly music, wacky editing, colourful demonstrations/analogies to illustrate scientific principles, and narration that sounds as if written for a toddler. In this respect it's almost as unwatchable as Michio Kaku's (who's ordinarily a bright guy) weirdly infantile Science of the Impossible series. (It's also an incredibly American show, formatwise, extremely brash and loud and fluffy.) I started watching the show as I'm a fan of Tyson, but I ended up disappointed. For now, the only regular series (as opposed to one-offs like Jim Al-Khalili's excellent shows on atoms and chemistry, or Sagan's Cosmos) I consider worth watching is BBC's Bang Goes the Theory (http://www.bbc.co.uk/programmes/b00lwxj1 http://www.bbc.co.uk/programmes/b00lwxj1), which is fairly obviously targeted at teens, but has some good content. Two of the hosts are fairly annoying generic twentysomethings who do the show as though it's some kind of music video programme, but the third guy is an adorable geek with an obvious passion for science and engineering, and they have some assisting hosts who are quite quirky.
  - th0ma5 15y ago
    I can't agree with you more, on one hand the technical detail is somewhat increasing in American shows, but the over production and gimmicky nature certainly overshadows it. I'm always impressed by the technical level of BBC shows in comparison, but the best content is online, usually in lectures, and not TED.
    - 15y ago
deleted 15y ago
[deleted]
suprgeek 15y ago
Q:What is your favorite fact about the Universe? A:That is will never end. That it's on a one way trip of expansion. Something that many find to be philosophically unsettling. My view is that if your philosophy is not unsettled daily then you are blind to all the universe has to offer. Priceless
- anjc 15y ago
  That's nice and all, but most humans in the world (including the western world) don't have the luxury of being able to let themselves be unsettled daily :/
  - wpietri 15y ago
    Most of them could have this luxury. They pick other luxuries first. Which is, in my view, a mistake. Those who seek out challenge tend to end up with a lot more luxury than those who don't.
    - anjc 15y ago
      This is probably a privileged viewpoint which is only possible in certain cases, i'm guessing (i'm not saying that you or me are privileged, necessarily...just that it's still a 'luxury' to some extent)
omnivore 15y ago
"pedagogical enthusiasm" - my new favorite term.

242 points by pbj 15y ago

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 each of those you pulled apart.

pavel_lishin 15y ago
Huh, I thought Quarks only existed as triplets.
- jessriedel 15y ago
  They only come in "colorless" sets. The "colors" (which are just suggestive names and have nothing to do with light colors) are Red, Green, and Blue, along with anti-Red, anti-Green, and anti-Blue. Therefore, there are basically two options: mesons, which contain a quark/anti-quark pair (e.g. one Green and one anti-Green) and baryons, which contain quark of each colors (RGB, or antiRGB). Tetraquarks, pentaquarks, and hexaquarks have been searched for in experiment and would not violate the colorless rule, but have never been found. Physicists would prefer to be able to calculate from first principles whether such states are possible, but it turns out that no one knows how to do the calculation because of the non-perturbative nature of the strong force. [Many caveats. For instance, any given hadron (the collective name for things made of quarks, which to date means only mesons and baryons) is not actually made up of quarks with definite color, but rather a quantum superposition of many possibilities. I think mesons, for example, are always a balanced superposition of R-antiR, G-antiG, and B-antiB. So you could never point to a given meson in an experiment and say "that meson was blue-antiblue".]
- deleted 15y ago
  [deleted]
Herring 15y ago
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.
- jessriedel 15y ago
  >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 and the radius of the earth) over which distances are perfectly sensible. Likewise, before the deep inelastic scattering experiments of the 60's, physicist had no direct evidence that neutrons and protons had any internal structure. All they could say is "we know that if they have internal structure, it's smaller than this length scale". [FYI: The Planck scale is (arguably!) where the notion of size becomes murky because quantum fluctuations in the background spacetime (against which the sizes of things are measured) become substantial. Of course, no one has ever seen (even indirect) evidence of a quantum fluctuation in spacetime. And, as is well known, appling quantum mechanics to gravity and spacetime is full of difficulties. But most physicists believe there are such quantum effects because it seems damn near impossible to reconcile a classical spacetime with quantum everything else.]
  - Herring 15y ago
    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.
    - nobody3141592 15y ago
      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
tkahn6 15y ago
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.
- fragsworth 15y ago
  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?
- Jach 15y ago
  This answer bothered me. Is he just saying that any supposed delays of "light" we can set up through experiment are really just delays in instantaneous absorption/emission pairs, or is he talking about entangled photons, or some preferred space of simultaneity, or photons not being particles but vectors in a timeless configuration space?
  - galadriel 15y ago
    Most probably he is talking about the fact that proper time for all events in Photon's own frame is zero, i.e. a frame that move with speed of light will notice that all events are instantaneous.
  - teamonkey 15y ago
    I loved this reply. Clarifying and correct, as far as I can tell. http://www.reddit.com/r/IAmA/comments/mateq/i_am_neil_degrasse_tyson_ama/c2zga4o http://www.reddit.com/r/IAmA/comments/mateq/i_am_neil_degras...
- jahmed 15y ago
  Obligatory xkcd:Prairie http://xkcd.com/967/ http://xkcd.com/967/
- 15y ago

feralchimp 15y ago

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 15y ago
[deleted]
Waxbar1 15y ago
Interestingly, South Park has been conveying this message message for over 10 years, and I think the generation that grew up watching South Park innately understands this already and at a younger age.

akkartik 15y ago

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

pavel_lishin 15y ago
Why is that so weird?
cbo 15y ago
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.
- Dn_Ab 15y ago
  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.
  - showerst 15y ago

jrappleye 15y ago

My personal favorite: Q: If you could add one course to a student's curriculum, what would it be?" A: Course title every university should offer: "How to tell when someone else is full of shit"

malkia 15y ago

He is one of my heroes. So charming, funny and educating at the same time. His speech on the islam downfall in the 13th century due to some "prophet" claiming that math and devil were interconnected was much enlightening on how religion actually stops scientific progress.

kloncks 15y ago
I was in the middle of one of his talks and heard this exactly. I agree...but allow me to just correct one thing. The "prophet" was a sheikh/imam in Iraq (?) that said math and Satan were connected. Islam had - up until that time - managed to have some pretty amazing feats. That said, it's interesting how we blindly take advice from men with authority. Whether that's religious figures, famous people, or politicians.
- malkia 15y ago
  Thanks for the correction kloncks! Not trying to excuse myself, but I'm simply not good at remembering details. Would have to watch the video again!
  - kloncks 15y ago
    No worries! It's my view that religion often isn't the thing that impairs scientific learning. Rather it's men's interpretation of those events. Just needed to make that subtle correction :)
    - lukifer 15y ago
      Ideology is a superset of religion, and like fire, it can be used for either creation or destruction.
omarchowdhury 15y ago
Does that one instance preclude all of the other people that contributed to science, who also had faith?

davidhollander 15y ago

Anyone interested in NdGT, check out the show he hosts: Nova Science Now http://www.pbs.org/wgbh/nova/sciencenow/ http://www.pbs.org/wgbh/nova/sciencenow/ You can watch full episodes online, no commercial interruptions after they start. It does a good job at filling the popular science video niche, in addition to Through the Wormhole with Morgan Freeman.

lobster_johnson 15y ago
I have been looking for a good science show, but Nova scienceNOW wasn't it. Not so much the content as the absolutely juvenline format. Can someone explain how I have misunderstood and the show really is meant for kids? Because it's designed like a kid's show, complete with silly music, wacky editing, colourful demonstrations/analogies to illustrate scientific principles, and narration that sounds as if written for a toddler. In this respect it's almost as unwatchable as Michio Kaku's (who's ordinarily a bright guy) weirdly infantile Science of the Impossible series. (It's also an incredibly American show, formatwise, extremely brash and loud and fluffy.) I started watching the show as I'm a fan of Tyson, but I ended up disappointed. For now, the only regular series (as opposed to one-offs like Jim Al-Khalili's excellent shows on atoms and chemistry, or Sagan's Cosmos) I consider worth watching is BBC's Bang Goes the Theory (http://www.bbc.co.uk/programmes/b00lwxj1 http://www.bbc.co.uk/programmes/b00lwxj1), which is fairly obviously targeted at teens, but has some good content. Two of the hosts are fairly annoying generic twentysomethings who do the show as though it's some kind of music video programme, but the third guy is an adorable geek with an obvious passion for science and engineering, and they have some assisting hosts who are quite quirky.
- th0ma5 15y ago
  I can't agree with you more, on one hand the technical detail is somewhat increasing in American shows, but the over production and gimmicky nature certainly overshadows it. I'm always impressed by the technical level of BBC shows in comparison, but the best content is online, usually in lectures, and not TED.
  - 15y ago

deleted 15y ago

[deleted]

suprgeek 15y ago

Q:What is your favorite fact about the Universe? A:That is will never end. That it's on a one way trip of expansion. Something that many find to be philosophically unsettling. My view is that if your philosophy is not unsettled daily then you are blind to all the universe has to offer. Priceless

anjc 15y ago
That's nice and all, but most humans in the world (including the western world) don't have the luxury of being able to let themselves be unsettled daily :/
- wpietri 15y ago
  Most of them could have this luxury. They pick other luxuries first. Which is, in my view, a mistake. Those who seek out challenge tend to end up with a lot more luxury than those who don't.
  - anjc 15y ago
    This is probably a privileged viewpoint which is only possible in certain cases, i'm guessing (i'm not saying that you or me are privileged, necessarily...just that it's still a 'luxury' to some extent)

omnivore 15y ago

"pedagogical enthusiasm" - my new favorite term.