Military Has Been Researching "Anti-Gravity" For Nearly 70 Years • Hacker News Board

Re: Military Has Been Researching "Anti-Gravity" For Nearly 70 Years

#111

Post by salty_biscuits » Thu, Oct 31, 2019, 1:05 PM UTC

ISL wrote: post #51

lisper wrote: post #46

Earlier quoted context omitted.

How much money does society need to spend supporting the work you do before we can safely conclude that Einstein was actually correct and we don't need to test it any more?

That's a great and important question. (doubly so for me, as constrained resources may see me leave the field, to which I have devoted my entire professional life, in the coming months) We are perennially grateful for the support we receive to do the work that we do. To a high degree of approximation, Einstein's predictions are very, very correct. We are trying to look very carefully at Nature because we don't think…

"GPS is impossible without corrections from both special relativity and general relativity"

I appreciate your comments in general, but I feel that this point needs to be tempered. Yes there are corrections due to SR and GR effects in GNSS, but they tend to get lost in the morass of the least squares residuals compared to all the other much bigger effects, like clock errors, orbital errors, ionosphere delays, etc, etc.

Re: Military Has Been Researching "Anti-Gravity" For Nearly 70 Years

#112

Post by sushibowl » Thu, Oct 31, 2019, 1:07 PM UTC

concordDance wrote: post #105

duchenne wrote: post #61

I love the following Feynman's quote: ``In those days, one of the theories proposed was that the planets went around because behind them were invisible angels, beating their wings and driving the planets forward. You will see that this theory is now modified! It turns out that in order to keep the planets going around, the invisible angels must fly in a different direction and they have no wings. Otherwise, it is a s…

> why mass attracts mass What kind of answer could you get for that kind of question? Seems to me that "Why?" Is the question you can ask endlessly of any answer. Often I think a "why?" questions is just a request for a compelling narrative... Maybe that is literaly what "why?" means?

Richard Feynman himself has a reply similar to yours in the documentary called "Fun To Imagine" when he is asked a why question, in that case related to the magnetic force:

https://www.youtube.com/watch?v=36GT2zI8lVA

Indeed, questions of why are often metaphysical and can't truly be answered within the framework of physics.

Re: Military Has Been Researching "Anti-Gravity" For Nearly 70 Years

#113

Post by sgt » Thu, Oct 31, 2019, 1:11 PM UTC

They'll at some point stumble across a Goa'uld device that does precisely that. But for the love of God, don't just plug it in!

Re: Military Has Been Researching "Anti-Gravity" For Nearly 70 Years

#114

Post by mschuster91 » Thu, Oct 31, 2019, 1:16 PM UTC

Erlich_Bachman wrote: post #93

nnq wrote: post #69

Earlier quoted context omitted.

Hopefully a (theoretically) infinite amount (assuming infinite time) ...theories should continuously be re-tested, although it probably makes sense to spend an exponentially lower and lower amount of money on re-testing theories we know are true. But they should be re-tested, even if some experiments you'd only redo every 50 years or so! For two important reasons: 1. as a species we must maintain technical capability…

Wouldn't we very quickly notice if any of the basic laws of phsyics would change, or if any of the physical constants would nudge even a fraction of a million - because our machines (like microchips, radios, like quantum computers, like satellites, GPS, etc. etc.) would stop working as they were intended?

Yeah, we would notice it, but that's not the point of re-running these kinds of experiments.

Just look what humanity was able to do in the Space Race with "computers" less powerful than an ordinary standard wristwatch of today: going to the moon, surviving there and coming back. Today? If it were not for SpaceX, the US would not have a path to access to its own manned transfer capability.

If we do not use abilities, we lose them. Knowledge gets forgotten, data bit-rots, machinery rusts apart.

Re: Military Has Been Researching "Anti-Gravity" For Nearly 70 Years

#115

Post by Grimm665 » Thu, Oct 31, 2019, 1:17 PM UTC

newsbinator wrote: post #39

What is the currently accepted answer to the question, "what is gravity"?

This video by Vsauce really put it in a way that made it stick for me.

https://www.youtube.com/watch?v=Xc4xYacTu-E

Re: Military Has Been Researching "Anti-Gravity" For Nearly 70 Years

#116

Post by Gustomaximus » Thu, Oct 31, 2019, 1:22 PM UTC

garmaine wrote: post #21

kiba wrote: post #6

Earlier quoted context omitted.

Time travel back into the past is understood to be impossible.

Physicist here (by degree, not profession). What you state is not true: by currently accepted physical theories, time travel to the past IS very much possible. It's known as a "closed, time-like curve" in the literature. Now, most mechanisms explored for doing so wouldn't allow travel back further than the initial creation of the time travel device, so you could say that time travel to our past is not possible since…

Definitely not a physicist here but isn't forward time travel somewhat possible by approaching speed of light? I read about effects where if I left earth, travelled very fast a year to me might be many to earth. Could a person not therefore 'travel fast' somewhere and come back so a place like earth had advanced significantly in time relative to them?

Not sure if that is time travel in a 'jump to a new time' sense but it effectively is. And I wonder how far you could push that with theoretical technology. 1 day for 1000 years type thing...

Re: Military Has Been Researching "Anti-Gravity" For Nearly 70 Years

#117

Post by tomxor » Thu, Oct 31, 2019, 1:22 PM UTC

ISL wrote: post #51

lisper wrote: post #46

Earlier quoted context omitted.

How much money does society need to spend supporting the work you do before we can safely conclude that Einstein was actually correct and we don't need to test it any more?

That's a great and important question. (doubly so for me, as constrained resources may see me leave the field, to which I have devoted my entire professional life, in the coming months) We are perennially grateful for the support we receive to do the work that we do. To a high degree of approximation, Einstein's predictions are very, very correct. We are trying to look very carefully at Nature because we don't think…

Good response. I think this is the clearest way to explain to people why researching X is important, the benefits to humanity are almost always in side effects of any research, development and engineering feats: The techniques, understanding and technology required to _attempt_ to figure out or achieve X are usually far more valuable than X itself and are often not known ahead of time, but can be invaluable to the future of humanity.

The problem is researchers are far more likely to express their interested in X to the public - quite right - since that must be their passion for the significant focus required to follow that path. This is what the public find so unintuitive, we need to focus on X to benefit from Y, although we don't know what Y is, but it has the potential to be far more useful than anything more direct.

Reminds me of the more literal explanation in a letter by Ernst Stuhlinger at NASA in response to a similar question:

https://www.forbes.com/sites/startswithabang/2017/10/26/even...

Re: Military Has Been Researching "Anti-Gravity" For Nearly 70 Years

#118

Post by JoeAltmaier » Thu, Oct 31, 2019, 1:33 PM UTC

Not surprising in the 1950's. Every other science fiction author was a believer - they wrote endlessly about shields that 'blocked' gravity, fields that interacted with gravity, materials that had variable gravitational force, and on and on. Their speculation helped fuel/was fueled by science investigation of that era.

Re: Military Has Been Researching "Anti-Gravity" For Nearly 70 Years

#119

Post by conexions » Thu, Oct 31, 2019, 1:37 PM UTC

For anyone interested, a book was written on this about 15 years ago by a reporter from "Janes Defense Weekly". "The Hunt for Zero Point: Inside the Classified World of Antigravity Technology". Not as tin-hat as you might think, mostly a story of a lot of dead ends while trying to research some DARPA dark projects.

Re: Military Has Been Researching "Anti-Gravity" For Nearly 70 Years

#120

Post by Erlich_Bachman » Thu, Oct 31, 2019, 2:06 PM UTC

mschuster91 wrote: post #114

Erlich_Bachman wrote: post #93

Earlier quoted context omitted.

Wouldn't we very quickly notice if any of the basic laws of phsyics would change, or if any of the physical constants would nudge even a fraction of a million - because our machines (like microchips, radios, like quantum computers, like satellites, GPS, etc. etc.) would stop working as they were intended?

Yeah, we would notice it, but that's not the point of re-running these kinds of experiments. Just look what humanity was able to do in the Space Race with "computers" less powerful than an ordinary standard wristwatch of today: going to the moon, surviving there and coming back. Today? If it were not for SpaceX, the US would not have a path to access to its own manned transfer capability. If we do not use abilities,…

> "computers" less powerful than an ordinary standard wristwatch of today: going to the moon, surviving there and coming back

This is more of a statement of how little computing power is needed for rudimentary space travel. The technology itself was quite advanced, just in other aspects than raw computing power.