I hadn't forgotten Gargarin at all, just used the first launch example that I personally watched as a boy. Yes the Apollo 1 tragedy was terrible but likely crucial in the ultimate success of the program.
I remember Henilein's novel "The Family Stone" (originally titled "The Rolling Stones" but apparently there was some rock'n'roll band that got big and took over the name). In college I was reading through all his novels, got a few pages in to where he was talking about automobiles and pistons "foolishly going back and forth" in cylinders, and realized I had first read the novel around age 8 or 10. Regardless, his point in this passage (which now I think even he knew was much more literary than scientific - this was one of his "juveniles," written for children) was about the forms of travel developed over the time of humanity, from walking to horse and buggy, through automobiles and then to "the most advanced and efficient form of travel" [not an exact quote, but that's as I remember his intent], rocketry.
The irony here is anything traveling in the air or into space is going to take a whole lot more fuel than something moving the same crew/cargo on land, but whatever.
This does lead to the idea of a skyhook or space elevator, a huge wire/rope/structure connected to Earth at the Equator and going up past geostationary orbit where a counterweight maintains tension to keep it up. A vehicle could ride up or down on this thing from Earth to space with something approaching (meaning within an order of magnitude of) the minimal energy required to move a mass from the surface to that point in orbit. This would be hugely less expensive than rockets, even taking into account Spacex reusing the first stage. The big problem with a skyhook is making it, and there are at least two big problems with that - coming up with the money (it would eventually pay for itself, but the cost makes a Mars mission look like peanuts), and coming up with the engineering (even the latest, highest strength-to-weight-ratio materials appear marginal for such a project).
I've got yet another Universe-Expanding question. Heinlein's novel has people flying rockets around and landing on the Moon vertically. engine-pointing-down on a regular basis. Did anyone ever seriously consider doing this for real (for ANY rocket or booster) before Elon Musk and Spacex?
The irony here is anything traveling in the air or into space is going to take a whole lot more fuel than something moving the same crew/cargo on land, but whatever.
This does lead to the idea of a skyhook or space elevator, a huge wire/rope/structure connected to Earth at the Equator and going up past geostationary orbit where a counterweight maintains tension to keep it up. A vehicle could ride up or down on this thing from Earth to space with something approaching (meaning within an order of magnitude of) the minimal energy required to move a mass from the surface to that point in orbit. This would be hugely less expensive than rockets, even taking into account Spacex reusing the first stage. The big problem with a skyhook is making it, and there are at least two big problems with that - coming up with the money (it would eventually pay for itself, but the cost makes a Mars mission look like peanuts), and coming up with the engineering (even the latest, highest strength-to-weight-ratio materials appear marginal for such a project).
I've got yet another Universe-Expanding question. Heinlein's novel has people flying rockets around and landing on the Moon vertically. engine-pointing-down on a regular basis. Did anyone ever seriously consider doing this for real (for ANY rocket or booster) before Elon Musk and Spacex?
Yes, though (and especially after the perceived-embarrassment of Sputnik) Shepard was the first AMERICAN in space, and with Americans writing the history books I grew up with, you could only learn about others' achievements in the footnotes at best, or in an encyclopedia.
Yes, and it was one of those engineering things that hadn't been thoroughly thought through. The capsule on the pad was configured "for launch," pure oxygen atmosphere at 14PSI, sea level pressure. Just about anything burns near-explosively in such an atmosphere, and the slightest spark could and did start it. Later flights started with (as I recall) a "normal" mix of oxygen and nitrogen, and once in space the pressure is lowered to around 4PSI and the mix is bled off and replaced with pure oxygen, which is a lot less flammable (or however you say it) at the lower pressure.
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I actually watched Sputnik in 1957. I was just 3 years old, but I could feel the excitement around me from my family. We heard it bleep on the radio too. My earliest childhood memory.
Now, that Oxygen thing now makes sense! A lethal schoolboy mistake to have an atmosphere of pure Oxygen at ground pressure. I have seen what that can do. Whatever were they thinking of?
Makes more sense in space at 20% atmospheric pressure. Nitrogen does nothing in that context... 😎
Live and learn, eh? Tell that to the Astronaut's widows and families. 😱
I was overly excited during the SpaceX launch, but I think I gleaned that Elon Musk and SpaceX is getting $2.6Bn for 6 missions. Boeing are getting $4.2Bn for whatever they contribute next.
Which brings us back to SpaceX's remarkable ability to land a rocket on a copy of a broadsheet newspaper from a 100 miles. TBH, not many cricket fast bowlers could hit a broadsheet from 22 yards regularly, and I know this game.
Boeing, on the other hand, design aeroplanes that go DOWN when the pilot want them to go UP. 😱
Boeing 737 MAX groundings - Wikipedia
So as a successful betting man on the horses, my money is on Elon Musk here. Or at Cheltenham, in the real thing, on Irish Horse Trainer Willy Mullins.
BTW, did anybody notice that the coverage of the first stage SpaceX rocket blanked out on landing. I think they were hiding some clever stuff. 😀
Now, that Oxygen thing now makes sense! A lethal schoolboy mistake to have an atmosphere of pure Oxygen at ground pressure. I have seen what that can do. Whatever were they thinking of?
Makes more sense in space at 20% atmospheric pressure. Nitrogen does nothing in that context... 😎
Live and learn, eh? Tell that to the Astronaut's widows and families. 😱
I was overly excited during the SpaceX launch, but I think I gleaned that Elon Musk and SpaceX is getting $2.6Bn for 6 missions. Boeing are getting $4.2Bn for whatever they contribute next.
Which brings us back to SpaceX's remarkable ability to land a rocket on a copy of a broadsheet newspaper from a 100 miles. TBH, not many cricket fast bowlers could hit a broadsheet from 22 yards regularly, and I know this game.
Boeing, on the other hand, design aeroplanes that go DOWN when the pilot want them to go UP. 😱
Boeing 737 MAX groundings - Wikipedia
So as a successful betting man on the horses, my money is on Elon Musk here. Or at Cheltenham, in the real thing, on Irish Horse Trainer Willy Mullins.
BTW, did anybody notice that the coverage of the first stage SpaceX rocket blanked out on landing. I think they were hiding some clever stuff. 😀
Heinlein went one step further in "Tunnel in the Sky" when overpopulation on Earth is averted by the invention of teleportation, called the "Ramsbotham jump", which is used to send Earth's excess population to colonize other planets.
As for the space elevator, you need look no further than to Arthur C. Clarke and his novel "The Fountains of Paradise". The Space Elevator: 'Thought Experiment', or Key to the Universe? - SpaceRef
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Hate to mention this, but Science Fiction makes some spectacular misses sometimes too.
I mean, do you really believe we will be saved from Martians by playing them Yodels from Slim Whitman?
More likely to drive US mad, IMO. 😱
This weeks dose of seriously confusing new science comes from Quanta Magazine:
Quanta Magazine
Black Holes again. But I like this article. Symmetry breaking, dimensional analysis, the "Swamplands" of String theory. All good, IMO.
And how about a possible hole in the Standard Model?
Quanta Magazine
"Bottom" Quarks, eh? Ooh, er, missus. 😀
I mean, do you really believe we will be saved from Martians by playing them Yodels from Slim Whitman?
More likely to drive US mad, IMO. 😱
This weeks dose of seriously confusing new science comes from Quanta Magazine:
Quanta Magazine
Black Holes again. But I like this article. Symmetry breaking, dimensional analysis, the "Swamplands" of String theory. All good, IMO.
And how about a possible hole in the Standard Model?
Quanta Magazine
"Bottom" Quarks, eh? Ooh, er, missus. 😀
Let's be clear, 'Mars Attacks!' is a hilarious spoof on the science fiction genre.
So, having struggled to get my head round 'black holes', I'm now being confronted with 'extremal black holes'!
Mass, M, is measured in the fundamental SI unit, the kilogram (kg).
Charge, Q (=It), is measured in terms of the fundamental SI unit of current, the ampere (A) and the fundamental unit of time, the second (s).
I'm puzzled, Steve. How can Q and M be "converted into the same fundamental units"?
So, having struggled to get my head round 'black holes', I'm now being confronted with 'extremal black holes'!
Mass, M, is measured in the fundamental SI unit, the kilogram (kg).
IIRC the kg is no longer a fundamental SI unit, maybe that helps?
BIPM - measurement units
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I remember that revision from 2018! The kilogram remains a base unit. Are you saying that this revision answers my question, Scott?
No just wondering, I had the naive thought that since since charge, Q, could be electrons which have a mass you now have an expression that has all fundamental constants. But the mass of a charged particle depends on the particle so (I saw a physicist post elsewhere) the equivalence is meaningless.
The seven defining constants of the SI are:
the caesium hyperfine frequency DeltanuCs;
the speed of light in vacuum c;
the Planck constant h;
the elementary charge e;
the Boltzmann constant k;
the Avogadro constant NA; and
the luminous efficacy of a defined visible radiation Kcd.
I wouldn't know most of those from a hole in the ground, TBH. 😱
Anyhow, this Black Hole stuff might be fun to engage the old lemon:
Quanta Magazine
There are three Physics papers cited. They are not as easy a read as the Quanta article, but we ought to be able to do something with dimensional analysis. All you have to do is equate quantities with the same dimensions in fundamental units. For instance E=MC is dimensionally wrong, whereas E=MC^2 works. You follow?
After a long day with Bingo at The Drones Club yesterday, I might need to get Jeeves to help out with the serious Cerebellum stuff, but I'm up for this. 😀
the caesium hyperfine frequency DeltanuCs;
the speed of light in vacuum c;
the Planck constant h;
the elementary charge e;
the Boltzmann constant k;
the Avogadro constant NA; and
the luminous efficacy of a defined visible radiation Kcd.
I wouldn't know most of those from a hole in the ground, TBH. 😱
Anyhow, this Black Hole stuff might be fun to engage the old lemon:
Quanta Magazine
There are three Physics papers cited. They are not as easy a read as the Quanta article, but we ought to be able to do something with dimensional analysis. All you have to do is equate quantities with the same dimensions in fundamental units. For instance E=MC is dimensionally wrong, whereas E=MC^2 works. You follow?
After a long day with Bingo at The Drones Club yesterday, I might need to get Jeeves to help out with the serious Cerebellum stuff, but I'm up for this. 😀
I'm au fait with dimensional analysis. However my question is, how can it be used to justify the following statement in the Quanta article you liked? 😕
Been finding out more about these theoretical extremal black holes. 🙂
The theory coupling Einstein gravity to electromagnetism contains black hole solutions for which the mass M equals, or exceeds, in Planck units, the charge Q.
Note the emphasis on Planck units. The 'fundamental units' to which the Quanta article refers are actually 'Planck units'!
In physical cosmology, Planck units are a set of units of measurement defined exclusively in terms of five universal physical constants, in such a manner that these five physical constants take on the numerical value of 1 when expressed in terms of these units.
It would appear that the relationship between Q and M referred to in the Quanta link is only valid if we refer to the the dimensionless numerical values of these quantities measured in terms of Planck units.
Read more about Planck units here: Planck units - Wikipedia
The theory coupling Einstein gravity to electromagnetism contains black hole solutions for which the mass M equals, or exceeds, in Planck units, the charge Q.
Note the emphasis on Planck units. The 'fundamental units' to which the Quanta article refers are actually 'Planck units'!
In physical cosmology, Planck units are a set of units of measurement defined exclusively in terms of five universal physical constants, in such a manner that these five physical constants take on the numerical value of 1 when expressed in terms of these units.
It would appear that the relationship between Q and M referred to in the Quanta link is only valid if we refer to the the dimensionless numerical values of these quantities measured in terms of Planck units.
Read more about Planck units here: Planck units - Wikipedia
This is definitely one to sleep on.
The 2018 paper has a lot of mention of Boltzmann's constant k.
AFAIK, this means Temperature. A very chemistry concept that I am very vague about. Haven't done chemistry for 50 years.
Q charge, M mass and Planck Action or Information h I can do easily enough. Grew up with that stuff.
It's the new SI units I am having trouble with.
I always thought Gerard van T'Hooft and Lenny Susskind were a bit vague on information theory (which I am good at) and Entropy S (which I am vaguer about) in Black Holes.
They thought information is never destroyed falling into a Black Hole. Which left Stephen Hawking with egg on his face. I question that. A Black Hole is not a tape recorder, IMO.
I believe the current belief is that the surface area of a Black Hole is the main event, defined by 4x Pi x r^2. The information or entropy density when divided by the Planck area. Not sure which.
But seriously, Galu. This is not as easy as I thought. 😱
The 2018 paper has a lot of mention of Boltzmann's constant k.
AFAIK, this means Temperature. A very chemistry concept that I am very vague about. Haven't done chemistry for 50 years.
Q charge, M mass and Planck Action or Information h I can do easily enough. Grew up with that stuff.
It's the new SI units I am having trouble with.
I always thought Gerard van T'Hooft and Lenny Susskind were a bit vague on information theory (which I am good at) and Entropy S (which I am vaguer about) in Black Holes.
They thought information is never destroyed falling into a Black Hole. Which left Stephen Hawking with egg on his face. I question that. A Black Hole is not a tape recorder, IMO.
I believe the current belief is that the surface area of a Black Hole is the main event, defined by 4x Pi x r^2. The information or entropy density when divided by the Planck area. Not sure which.
But seriously, Galu. This is not as easy as I thought. 😱
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We're into physics beyond the standard model and it's hard enough getting one's head around that, never mind supersymmetry and the like!
And, the symbol Q can refer to 'supercharge', an operator which transforms bosons into fermions, and vice versa. Apparently supercharge is a spinor that carries one half unit of spin and may be visualized as a vector pointing along the Möbius band!
You see, I too can ramble on about this stuff for ages. Each click on a blue Wiki word or phrase results in an exponential growth of concepts that I will never understand! 😀
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Wikipedia out of all references?! Wikipedia can easily be vandalised. It is far better to use a good reference library if you have access to one.
P.S.
University students who quote Wikipedia in their assignments are heavily penalised for a good reason: Wikipedia is unreliable. Full stop.
Your snipping of my post is very unfair and misleading, edbarx!Originally Posted by Galu
Been finding out more about these theoretical extremal black holes. 🙂
[snip]
Read more about Planck units here: Planck units - Wikipedia
In an attempt to learn about extremal black holes, I accessed scholarly papers available on the web such as: http://cds.cern.ch/record/236255/files/9202004.pdf
The Wiki link was simply to allow access to information on Planck units and I have no reason to suspect that the information therein is wildly misleading.
I know Wiki is frequently dubious. Especially with anything political.
But a safish source on Maths and Physics.
It's the new SI units that give me trouble.
the caesium hyperfine frequency DeltanuCs;
the speed of light in vacuum c;
the Planck constant h;
the elementary charge e;
the Boltzmann constant k;
the Avogadro constant NA; and
the luminous efficacy of a defined visible radiation Kcd.
But I am confident we can do this. Quanta Magazine
I've taken leaps into the unknown before. It's what it's all about. Future is uncertain, an' all that. But that's life as an adventure. 😀
And I don't think we are moving beyond the Standard Model here. Even Lenny Susskind, considered the big daddy of String Theory has not abandoned the Standard Model. He's one of the best on the Standard Model.
Look at this way. 26 dimensional Bosonic String Theory is way beyond most of us. If I had any idea what it was about, my name would be Ed Witten. But dimensional analysis is really just 2 + 2 = 4. And I can do that.
But a safish source on Maths and Physics.
It's the new SI units that give me trouble.
the caesium hyperfine frequency DeltanuCs;
the speed of light in vacuum c;
the Planck constant h;
the elementary charge e;
the Boltzmann constant k;
the Avogadro constant NA; and
the luminous efficacy of a defined visible radiation Kcd.
But I am confident we can do this. Quanta Magazine
I've taken leaps into the unknown before. It's what it's all about. Future is uncertain, an' all that. But that's life as an adventure. 😀
And I don't think we are moving beyond the Standard Model here. Even Lenny Susskind, considered the big daddy of String Theory has not abandoned the Standard Model. He's one of the best on the Standard Model.
Look at this way. 26 dimensional Bosonic String Theory is way beyond most of us. If I had any idea what it was about, my name would be Ed Witten. But dimensional analysis is really just 2 + 2 = 4. And I can do that.
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