Cosmos - With Neil deGrasse Tyson
- Thread starter Greylock Crescent
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If you were to make a study to investigate if people could feel if someone gazes at them, I'm pretty certain that it would turn out not to be the case at all.
It's based on selective attention. Like the impression that I mysteriously keep seeing 9/11 numbers every time I look at a watch or telephone numbers or whatever. The truth is that I only remember the instances in which a 9/11 number showed up, but that in 99% of the time I see numbers that have no relation to it at all.
So people keep saying they can feel it when someone gazes at them, because they only pay attention to the times where their random feeling and that someone did look at them matched.
What DOES impress me is the ability to tell if someone is looking at you, even if that someone is pretty far away. That our eyes can determine the position of someone else's iris, AND that our brain can reliably calculate their line of view, that is amazing.
It's based on selective attention. Like the impression that I mysteriously keep seeing 9/11 numbers every time I look at a watch or telephone numbers or whatever. The truth is that I only remember the instances in which a 9/11 number showed up, but that in 99% of the time I see numbers that have no relation to it at all.
So people keep saying they can feel it when someone gazes at them, because they only pay attention to the times where their random feeling and that someone did look at them matched.
What DOES impress me is the ability to tell if someone is looking at you, even if that someone is pretty far away. That our eyes can determine the position of someone else's iris, AND that our brain can reliably calculate their line of view, that is amazing.
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This thread was much more fun when we were arguing about the animations and Patrick Stewart.
Agreed. BS like the *above* is why I stopped posting in TNZ... at a certain point it stops being intellectual discussion and becomes purely personal attack. Sometimes by the second post in a thread.
I haven't missed TNZ a bit. 
Anyway, something that Cosmos probably doesn't have time to talk about, but which is as interesting as the episode itself, was the follow up on how we learned to make diffraction gratings to make spectroscopy accurate and practical.
To make a useful diffraction grating required carving microscopic parallel lines by dragging a diamond across a piece of metal to make grooves, roughly 1000 per millimeter, with exactly equal spacing, over an area several inches on a side. And you have to do this by building a machine tool in your basement (anywhere else would have too much vibration from passing footsteps), and the only parts you have are things like screws, wheels, and leather belts. In comparison, building a large reflecting telescope is easy.
At that level of precision, steel acts like rubber, the whole machine acts like a seismograph, and even a small screw will compress ten times more than the width of the line you're trying to scribe. And the machine has to stroke back and forth thousands and thousands of times, and do it almost perfectly, without snagging or jumping due to friction.
Due to thermal expansion, the machine (called a "ruling engine") has to be left running for hours before you even let the diamond touch the metal. Worse, to complete a grating often required the machine to run for days, and one slip up, even a large truck driving by, could render the grating useless.
Lot's of famous scientists spent their lives obsessively tuning and rebuilding their machines, like Albert Michelson who measured the speed of light, showed it was equal in all directions, and showed that we're not moving through aether. Most of his life was spent tweaking his ruling engine. Many other scientists did the same, often spending years of twiddling before they got one good grating, and the machines themselves were famous in scientific circles. Only one amateur ever built one that worked (account), and the Japanese didn't manage to build a working ruling engine until the 1960's (Nikon link).
By the 1950's things advanced because we could apply interferometry and electronic feedback to the machines. Yet, even as late as the 1970's there were only fifty working ruling engines in the entire world, because making motions to that precision is astoundingly difficult.
We eventually learned how to copy a good master diffraction grating, much like we now stamp DVD's, so you might think the bizarre technological endeavor of the precision motions of ruling engines would come to a close. But then came the huge, huge need to index semiconductor chips around, and do so with optical precision, and the equipment we use to do that is often the direct descendant of a ruling engine, often built by the same people. If we hadn't learned how to make good diffraction gratings, we might not be on the Internet right now.
Another link on diffraction gratings and ruling engines.
Link to Zeiss mechanically ruled diffraction gratings.
Anyway, something that Cosmos probably doesn't have time to talk about, but which is as interesting as the episode itself, was the follow up on how we learned to make diffraction gratings to make spectroscopy accurate and practical.
To make a useful diffraction grating required carving microscopic parallel lines by dragging a diamond across a piece of metal to make grooves, roughly 1000 per millimeter, with exactly equal spacing, over an area several inches on a side. And you have to do this by building a machine tool in your basement (anywhere else would have too much vibration from passing footsteps), and the only parts you have are things like screws, wheels, and leather belts. In comparison, building a large reflecting telescope is easy.
At that level of precision, steel acts like rubber, the whole machine acts like a seismograph, and even a small screw will compress ten times more than the width of the line you're trying to scribe. And the machine has to stroke back and forth thousands and thousands of times, and do it almost perfectly, without snagging or jumping due to friction.
Due to thermal expansion, the machine (called a "ruling engine") has to be left running for hours before you even let the diamond touch the metal. Worse, to complete a grating often required the machine to run for days, and one slip up, even a large truck driving by, could render the grating useless.
Lot's of famous scientists spent their lives obsessively tuning and rebuilding their machines, like Albert Michelson who measured the speed of light, showed it was equal in all directions, and showed that we're not moving through aether. Most of his life was spent tweaking his ruling engine. Many other scientists did the same, often spending years of twiddling before they got one good grating, and the machines themselves were famous in scientific circles. Only one amateur ever built one that worked (account), and the Japanese didn't manage to build a working ruling engine until the 1960's (Nikon link).
By the 1950's things advanced because we could apply interferometry and electronic feedback to the machines. Yet, even as late as the 1970's there were only fifty working ruling engines in the entire world, because making motions to that precision is astoundingly difficult.
We eventually learned how to copy a good master diffraction grating, much like we now stamp DVD's, so you might think the bizarre technological endeavor of the precision motions of ruling engines would come to a close. But then came the huge, huge need to index semiconductor chips around, and do so with optical precision, and the equipment we use to do that is often the direct descendant of a ruling engine, often built by the same people. If we hadn't learned how to make good diffraction gratings, we might not be on the Internet right now.
Another link on diffraction gratings and ruling engines.
Link to Zeiss mechanically ruled diffraction gratings.
Done on Mythbusters, surely? If not, then it's time they did.
Pish posh. Some of us still shoot rays out of our eyes.
They did it on Through The Wormhole. IIRC it was slightly better than random chance.
I actually quite liked this last episode's theme. Spectroscopy is a massively underrated innovation, and I'm all for it getting some love.
Generally speaking, though ... I'm not going to complain about the episodes that have already aired, but I personally would prefer if the show started shifting its focus away from the past, and towards the present and near future. Most of the stories the show has told so far could have already been told during Sagan's day and age. They're still good stories, but I'd rather the show focussed its efforts on getting people excited about science happening *right now*, or science that young viewers might see happen - or themselves take part in - during their life time.
That's part of the beauty of going back to Sagan's works for me. He'll often be enthusiastically talking about cool new things that might happen at some point in the future that have since happened. Cometary rendezvous, Mars rovers, observing impact events first-hand through telescopes - stuff like that. So far, Tyson's Cosmos has done little that might be equivalent 34 years from now.
As someone born after the last moon landing and Voyager launches, I can't at times help feeling that I just missed the great age of discovery, and space exploration just isn't as cool as it used to be. Sagan did a great job convincing people that this simply isn't true, and I wish Tyson was investing more time into this too. It wasn't true during Sagan's life, and it isn't now. Come on, bring on Curiosity, the exoplanets, Titan Mare Explorers, Europa ice drilling, Stirling-cooled Venus rovers, asteroid capture missions, in-situ resource utilization, telescopes on the far side of the moon, and manned missions to Ceres!
Generally speaking, though ... I'm not going to complain about the episodes that have already aired, but I personally would prefer if the show started shifting its focus away from the past, and towards the present and near future. Most of the stories the show has told so far could have already been told during Sagan's day and age. They're still good stories, but I'd rather the show focussed its efforts on getting people excited about science happening *right now*, or science that young viewers might see happen - or themselves take part in - during their life time.
That's part of the beauty of going back to Sagan's works for me. He'll often be enthusiastically talking about cool new things that might happen at some point in the future that have since happened. Cometary rendezvous, Mars rovers, observing impact events first-hand through telescopes - stuff like that. So far, Tyson's Cosmos has done little that might be equivalent 34 years from now.
As someone born after the last moon landing and Voyager launches, I can't at times help feeling that I just missed the great age of discovery, and space exploration just isn't as cool as it used to be. Sagan did a great job convincing people that this simply isn't true, and I wish Tyson was investing more time into this too. It wasn't true during Sagan's life, and it isn't now. Come on, bring on Curiosity, the exoplanets, Titan Mare Explorers, Europa ice drilling, Stirling-cooled Venus rovers, asteroid capture missions, in-situ resource utilization, telescopes on the far side of the moon, and manned missions to Ceres!
Part of getting people excited about the future is teaching them about the past.
As much as I love science fiction - especially Star Trek - in some ways modern SF has done a real disservice to real-world astronomy. When Tyson (and Sagan before him in the original Cosmos) explained about the speed of light, how many of us on this forum honestly didn't immediately think about warp drive, warp engines, etc.? Even just as a momentary, passing thought?
How many kids ignore science news and documentaries as "boring" because SF movies and programs are already way past our current level of knowledge? How many kids are not even learning the basics of current scientific knowledge because their schools insist on teaching religion in their science classes instead of real science?
For these reasons, it's not a bad idea for the new Cosmos to teach what happened before. For a lot of viewers, this is the first time they're hearing it.
That's a good point - but I think they have plenty of time to do this - covering how private enterprise may lead the charge of space development after NASA and the governments blaze future trails, for example. It's been tough to drum up excitement of space exploration as a means to make a buck off of it, but IMO it will be what we'll see and a show like this could be a good way to do it.
But yes, they are doing an awful lot on historical achievement and I'm quite liking it too. Many of these stories were just a couple lines in a history text or a footnote in a university course. Now, they have quite a bit of knowledge (some apocryphal to be sure) added for the sake of teaching the importance of these lessons, and the overall theme of scientific investigation that the current series is trying hard to teach. It's focused on the past so far, but it's been a fun ride and I hope future episodes (sic) will shed more light on what's coming versus the importance of what's past.
Mark
But yes, they are doing an awful lot on historical achievement and I'm quite liking it too. Many of these stories were just a couple lines in a history text or a footnote in a university course. Now, they have quite a bit of knowledge (some apocryphal to be sure) added for the sake of teaching the importance of these lessons, and the overall theme of scientific investigation that the current series is trying hard to teach. It's focused on the past so far, but it's been a fun ride and I hope future episodes (sic) will shed more light on what's coming versus the importance of what's past.
Mark
Exactly.
If you for example don't know why previous models didn't work and why they were replaced, you are bound to make the same erroneous assumptions.
Going throught the whole process of reinventing the wheel (starting out with a square) because you don't know it already exists and that squares didn't work out, is a waste of time. It's fun for a Mythbusters episode, though.
Oh, I don't disagree. As I said, I'm not going to complain about the historical bits. I didn't say they should stop doing them. I said wouldn't mind if the show started shifting its focus.
Oh, I absolutely agree. Which is why what I said, with the relevant bits underlined, is:
And gave the following examples:
All things either happening now, or immediately viable if anyone was funding them. No more speculative now than the following things I quoted were for Sagan back in the day:
All stuff he loved to talk about decades before it happened, in a "wouldn't it be cool if [...]"-manner.
So while I see what you're saying, I'm not sure it's my post that you're disagreeing with. I wasn't saying that Cosmos should stop dealing with the fundamentals, or even that they should stop doing history completely. I wasn't saying they should start doing speculative science fiction. Just wishing for a shift of focus - which might be what they have in store for us anyway. Maybe this'll yet end up being a show that'll less be a testament to Sagan by telling stories he might have told, and more a testament to him by telling stories he'd have loved to hear.
I quite agree that it would be great to have stories he'd have loved to hear.Oh, I don't disagree. As I said, I'm not going to complain about the historical bits. I didn't say they should stop doing them. I said wouldn't mind if the show started shifting its focus.
Oh, I absolutely agree. Which is why what I said, with the relevant bits underlined, is:
And gave the following examples:
All things either happening now, or immediately viable if anyone was funding them. No more speculative now than the following things I quoted were for Sagan back in the day:
All stuff he loved to talk about decades before it happened, in a "wouldn't it be cool if [...]"-manner.
So while I see what you're saying, I'm not sure it's my post that you're disagreeing with. I wasn't saying that Cosmos should stop dealing with the fundamentals, or even that they should stop doing history completely. I wasn't saying they should start doing speculative science fiction. Just wishing for a shift of focus - which might be what they have in store for us anyway. Maybe this'll yet end up being a show that'll less be a testament to Sagan by telling stories he might have told, and more a testament to him by telling stories he'd have loved to hear.
I think we are basically in agreement, but am just pointing out that kids today are more exposed to flashy SF stuff on TV and in the movies that can make normal, real-world science seem slow and boring by comparison. I remember being guilty of that attitude myself, many years ago, so I do have experience with such a mindset.
I also remember when I did my student teaching back in the early '80s. I had a split class of Grade 3 and 4 kids, and their teacher was going to allow me to teach a science class to them - and casually mentioned she hadn't had any intention at all of doing astronomy. I was appalled at that, and wondered why kids of that age weren't going to get any sort of exposure to such knowledge. It would have been a disservice to them, particularly since my city doesn't have a planetarium, or even any in-city area that's relatively free from light pollution. So I did my class on astronomy, and had a Q&A that got a bit dicey in a couple of places when I realized that the teacher - who insisted on morning prayers, even though this was a public school - would not have been pleased if I'd told the kids flat-out that Genesis was wrong. Since she was the one who would have a huge say in whether or not I was allowed to continue in the B.Ed. program at the local college, I had to dance around some stuff. I hope current student teachers in the public system have an easier time of it. But given that parents are allowed to pull their kids out of classes that go into evolution and/or sex education, it's discouraging.
SF can inspire - after all, look at all the stuff we have now - and take for granted - because some Star Trek (or other SF) fans thought, "we should really make that cool gadget a reality."
SF can also frustrate. I remember reading a story back in elementary school about a kid who went to spend a school holiday with his dad, who was living and working on the Moon - in 1986 (I read the story back in the early '70s and it had been written many years before that). So when the '80s came around and there wasn't a hint of a colony on the Moon, nor any serious attempt to make it happen, I got frustrated and angry at the real-world politicians. I know Sagan was more into robotic exploration than manned missions, and I sincerely hope this new Cosmos has something in it about the importance of humans getting "out there" as well.
Maybe we'll see a "shift" as more episodes air. They've possibly scripted an "arc" that focuses upon the past in the earlier episodes, concerning our current situation in the middle segments and finally looks to the future by the final installments. By the conclusion of the series, Tyson will be addressing the audience, "Where do we go from here? Well, it's up to you. Maybe one of you will help resolve the current mysteries of (insert concept here)."
Sincerely,
Bill
Sincerely,
Bill
"So can anyone tell me what those bright things are in the night sky?"
"Streetlights!"
"no... Higher than those."
"Stadium lights?"
"no... Higher."
"Airplanes?"
"No... Higher."
"Drones?"
"No... Higher."
"The satellite thingies that beam down porn?"
"Um.... No... Higher."
So, why is this the most controversial show on TV?
Seems like there's always some hoopla up over it.
Seems like there's always some hoopla up over it.
A
Amaris
Guest
Some people don't like facts being explained in a factual manner.
Because stupid, uneducated people are afraid of things that they don't understand?
