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...The last one is new to me. Can you please give me a link to where I can read more about it? Thanks!
The disproof of parity conservation taught us that the physical laws of the universe are not uniform and that the universe does have a preferred orientation.Happy to. Is Wikipedia good enough for you? Because I can dig up primary sources if you like, but they are, of course, rather technical.
Basically, "parity conservation" says that if I build a mirror image of all my equipment, I should get exactly the same result irrespective of which set I'm using. This, in turn, is tied to another of Emmy Noether's theorems -- parity will be conserved if the laws of physics are invariant with respect to left/right. (God bless Emmy, who definitely has a place on my Smartest-Human-Being-in-History list.) Like conservation of energy and conservation of momentum (as well as conservation of weird stuff like charge, baryon number, and so forth) conservation of parity is one of those rock principles on which modern physics was based -- partly because the idea that the Universe gives a hamster turd whether or not the equipment is pointed towards Mecca seemed ludicrous.
... and then it went all went pear-shaped, when someone managed to demonstrate conclusively that, no, parity is not conserved (more specifically, the weak nuclear force, which largely controls atomic decay, does not conserve parity -- the other three appear to do so). Nobel prizes all around, boys!
(Isaac Asimov has speculated that this phenomenon may be related to the fact that all life on earth appears to use L-amino acids, which may be related to weak interactions that make D-amino acids less stable over evolutionary time scales. Most modern biologists consider this to be bunk, but it's an
Broken symmetries are not unknown in physics. After all, it is now believed that there was slightly more matter than anti-matter produced in the big-bang and that overage is represented in the matter seen today. The WHY of that imbalance however, is unknown... and may be unknowable. There are also observed broken symmetries in time. Chemical reactions for instance, aren't that reversible.
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I think I'll chalk this EM Drive up to insufficiently careful experimental design. Poking around on the Web tells me that for something like this to be true as advertised would require our understanding of physics to be rebuilt at the foundation.That would scare me a lot more if we hadn't had to rebuild our understanding of physics at the foundation level three times since 1900.
Relativity theory taught us that the traditional division between space and time was nonsensical.
Quantum theory taught us that the traditional division between matter and energy was nonsensical.
The disproof of parity conservation taught us that the physical laws of the universe are not uniform and that the universe does have a preferred orientation.
I think you're looking at it the wrong way. Don't see it as scary; see it as humanity improving.
Compare the last 100 years to the previous one thousand. How many times did we rewrite our basic understanding of physics over that longer time span?
And every time we make a major advance like this, it comes with massive new technologies and ways to help mankind, and even potentially ways to reduce our impact on the planet. Relativity gave us the possibility of nuclear power, and that was originally used to build a bomb. This is something used to build an engine. It's anyone's guess what new discoveries in energy this may lead to. Not to mention the discoveries outside that area.
If this works and we have to rewrite the laws of physics again... who knows? Maybe the understanding of how this works will lead us to being totally free of fossil fuels. This is an engine that is straight out of science fiction. What else will it lead to?
I'm excited.
Atomic energy was first used to make a bomb because there was a World War. In more serene times it could have been used as an energy source first, an engine if you wish...
Right now, times are not that serene all things considered
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different parts of the brain controling different parts of the body and some of those things being more important than others.I get that but it still does not explain why there should be this dissymmetry. Which AFAIK happens throughout the world hence is older than skin colors
I would be extremely skeptical of an origin in amino acid chirality of human (or simian, more accurately) handedness. First, the different stereoisomers of a given chemical are generally identical in behavior if you just consistent handedness throughout; the only time you even notice a difference is when you do something silly and mix stereoisomers.
Secondly, every form of life on Earth uses the same chirality, so why should handedness effects be confined to humans and their close relatives? We share all of our fundamental biochemistry with lizards, so why shouldn't lizards also be right-, er, -footed? However, we've only see evidence of side dominance in primates, not in lizards and not even in big cats.
This page lists (in accessible form) most of the theories that have been proposed about the origin of handedness. Some of them suffer from the same weakness I outlined above -- if, for example, it's due to facing in utero, why should that not affect other mammals? Others make more sense to me if only because are tied specifically to primate behavior. But I'll let you sort through and make your own credibility judgments.
Chiral molecules often do not share melting point, for example.
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Chiral molecules often do not share melting point, for example.
Not quite.
A chiral molecule and its enantiomer have the same melting point. Melting points differ when you get mixtures of differerent chiralities. (By the way, I used the term "stereoisomer" loosely in the previous post; the proper term is, of course "enantiomer." "Stereoisomer" is more general, but it's also more transparent a term.)
I get that but it still does not explain why there should be this dissymmetry. Which AFAIK happens throughout the world hence is older than skin colors
Hyper oversimplification but...
Left part of the brain controls right side of body
Right side of brain controls left half of body
This means that only left handed people are in their right minds...
this is probably because if Grog clocks on on your left with a club, you really need to get your left hand up in a hurry and don't want it going "oxydating freeway roadbump" when it should be going "block! block! block!"
If the left side of the brain controls spacial orientation and the right side controls art, more processing power on the left gets you better with thrown objects. The right makes you a better painter. One of those is evolutionarily more valuable. The handedness is just a... linked trait? Consequence of something else?
I get that but it still does not explain why there should be this dissymmetry. Which AFAIK happens throughout the world hence is older than skin colorsHyper oversimplification but...
Left part of the brain controls right side of body
Right side of brain controls left half of bodyThis means that only left handed people are in their right minds...
this is probably because if Grog clocks on on your left with a club, you really need to get your left hand up in a hurry and don't want it going "oxydating freeway roadbump" when it should be going "block! block! block!"
Brain lateralization goes back way before Grog was using clubs, and in fact, long before Grog's great-great-great-*-grandparents had mastered things like "breathing air."
The theory that combat prowess led to handedness has long been discredited.| 1 person marked this as a favorite. |
Just replicating the experiment would make me feel surer about it. Cold fusion looked good too until other people had problems getting the same results as Fleischmann & Pons.
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Back to the subject at hand... I think a group is trying to test the similar Cannae Drive in space next year? XD We really DO need to test these things in space, I think.
Thats a really expensive way to find out that there was a lead deposit on one side of the cave pulling on the experiment or something
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Just replicating the experiment would make me feel surer about it.
My understanding is that this experiment is a replication.
The authors of the paper in question are "White, Harold; March, Paul; Lawrence, James; Vera, Jerry; Sylvester, Andre; Brady, David; Bailey, Paul." The designer of the Em-drive is Roger Shawyer, who has published separately on this gizmo since roughly 2002.
As far as I know, Shawyer has no involvement with the recent paper.
There's also a replication by a Chinese group here. (Also here, same group.)
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If it makes you feel better, the Chinese are also testing it, and seem to be convinced that it's workable enough to keep investigating.
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When this came up in the media late last year, I hassled my brother about it (it's been a long while since I dabbled in astrophysics at uni and I'm hardly in touch with the community, whereas he is a professional working in the field).
At the time, the state of affairs was as follows:
- The thrust being produced was at the minimum limits of what could be measured with the equipment in question, making it suspect.
- No test could produce the same results that were originally claimed by the device's inventor.
- Given the miniscule magnitude of the thrust, it was and is exceedingly difficult to completely isolate the experiment from other factors that could be affecting either the test chamber or equipment.
- The same results were obtained from performing the test... on a cardboard box.
The general consensus among the scientific community is that while the media love it (everyone wants a Warp Drive), and it is worth playing with, it is the longest of long shots, unfortunately.
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Coriolis effect with the air around the lasers? try it in the southern hemisphere and see if its going the other way?
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- The same results were obtained from performing the test... on a cardboard box.
Damn. The secret of our Schrödinger stardrive for the feline overlord corrugated space armada has been revealed!
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If it makes you feel better, the Chinese are also testing it, and seem to be convinced that it's workable enough to keep investigating.
Well, the Third Reich invested a lot in occult studies and the USSR in studying psychic abilities
Spending money is a scientific proof of the vendor's business acumen only :-)
Yeah but if your enemy found out how to use pyrokinesis before you you would have egg on your face and the egg would be fried to for that matter.
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They won't do that until they figure out how it works. After all, the last thing you want is to find out too late that the engines you just sent up generate black holes in zero gravity. And when you can't explain the physics behind how something works, you can't rule that out.I'll take it seriously the day they actually stick it on a probe and try it out...
And then if it works, I'll start demanding a Pluto orbiter.
You don't understand scientists at all do you?
Of course they'd build one and try it just to see what happens. How else are they going to find out how it works? Or if it works.
I'm late to the party, but...
My favorite example of "how scientists are" is Poltergeist. Something spooky and unseen is pulling all the chairs toward the middle of your dining room. If your reaction is to put your kid on one of the chairs and measure how fast it moves under load conditions, you might be a scientist.| 2 people marked this as a favorite. |
If you remembered to substitute a bag of concrete for a child you might be an engineer instead
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If you put helmet on your kid and time him with a stopwatch you might be a race car driver.
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I'm late to the party, but...
My favorite example of "how scientists are" is Poltergeist. Something spooky and unseen is pulling all the chairs toward the middle of your dining room. If your reaction is to put your kid on one of the chairs and measure how fast it moves under load conditions, you might be a scientist.And you would quickly get fired from any lab worth speaking of for ethics violations if you're that willing to risk a human life without having first run through tests using inanimate objects or animals.
This isn't Nazi Germany or Pasteur's labs.
Also true.
(Joke) One benefit of a home lab: no pesky ethics committee to make you try it with the bag of concrete and the family dog first. (/Joke)
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(Joke) One benefit of a home lab: no pesky ethics committee to make you try it with the bag of concrete and the family dog first. (/Joke)
It's wife then dog then kid.
If you lose them just play a country music record backwards.
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I hate to go back to ether, but if you consider space as stuff, wouldn't vibrating a wedge shaped object back and forth propel you forward like one of those twisty scooters?
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I hate to go back to ether, but if you consider space as stuff, wouldn't vibrating a wedge shaped object back and forth propel you forward like one of those twisty scooters?
If you're asking an empirical question, try it out. The world works the way it does, irrespective of our theories about it.
If you're asking a theoretical question, "[consider] space as stuff" doesn't make much sense. The wedge would have to be pushing on something to send that something backwards, which would then generate a counterforce that would send the wedge and anything attached to it forward. Even then, you'd need to find some way to make sure that you didn't also push the something forward and send yourself back at the same time.
But the big question, of course, is what is the nature of the something against which you are pushing? According to standard theories, there is no such thing. So, yeah, you're basically going back to ether....
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Just replicating the experiment would make me feel surer about it. Cold fusion looked good too until other people had problems getting the same results as Fleischmann & Pons.
Lets be accurate here. NO ONE got the results that the pair were claiming they got.
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I was at a high-temperature chemistry conference in the early 90s and happened into a conversation among some of the more senior attendees about CF. Their take on it, IIRC, was that F&P's experimental apparatus couldn't have been used to extract the data on energy production that F&P claimed. Since this was a bunch of calorimetry experts, I figured they were in a good position to argue the point.
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Speaking of ether, I heard something interesting about dark matter recently on NPR: for all we know, there could be tons of the stuff all around us right this moment, even passing through our bodies. It almost never interacts with the kind of matter that we're made of, so we don't notice it.
That sounds a lot like ether (except for the "transmission medium for light waves" aspect of ether). If you had some way to increase the interaction of normal matter with dark matter, and only turned it on when the normal matter was traveling "backwards" in the resonant chamber of an EM-style drive, then you would have something to push against. Since it wouldn't interact with the rest of the ship, you'd go forward.
(Sure, it wouldn't work for many, many reasons, but it's fun to resurrect a discredited 19th Century theory like ether by substituting a 20th/21st Century buzzword like dark matter.)
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And that's almost as weird as the Quantum Zeno effect. XD
Speaking of ether, I heard something interesting about dark matter recently on NPR: for all we know, there could be tons of the stuff all around us right this moment, even passing through our bodies. It almost never interacts with the kind of matter that we're made of, so we don't notice it.
That sounds a lot like ether (except for the "transmission medium for light waves" aspect of ether). If you had some way to increase the interaction of normal matter with dark matter, and only turned it on when the normal matter was traveling "backwards" in the resonant chamber of an EM-style drive, then you would have something to push against. Since it wouldn't interact with the rest of the ship, you'd go forward.
(Sure, it wouldn't work for many, many reasons, but it's fun to resurrect a discredited 19th Century theory like ether by substituting a 20th/21st Century buzzword like dark matter.)
Didn't we recently learn that Dark Matter probably doesn't exist? Or at least not nearly in the amounts or the way we previously thought. As in, we were arrogant enough to make up a whole other type of theoretical matter because our existing technology wasn't able to "see" the matter that made something be as heavy as it was supposed to be. Then we used a better piece of technology and were able to see it, and now we are tossing 50 years of science out the nearest airlock.
I could be off on this, but I seem to remember hearing quite a bit about it lately.
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Speaking of ether, I heard something interesting about dark matter recently on NPR: for all we know, there could be tons of the stuff all around us right this moment, even passing through our bodies. It almost never interacts with the kind of matter that we're made of, so we don't notice it.
That sounds a lot like ether (except for the "transmission medium for light waves" aspect of ether). If you had some way to increase the interaction of normal matter with dark matter, and only turned it on when the normal matter was traveling "backwards" in the resonant chamber of an EM-style drive, then you would have something to push against. Since it wouldn't interact with the rest of the ship, you'd go forward.
(Sure, it wouldn't work for many, many reasons, but it's fun to resurrect a discredited 19th Century theory like ether by substituting a 20th/21st Century buzzword like dark matter.)
Didn't we recently learn that Dark Matter probably doesn't exist? Or at least not nearly in the amounts or the way we previously thought. As in, we were arrogant enough to make up a whole other type of theoretical matter because our existing technology wasn't able to "see" the matter that made something be as heavy as it was supposed to be. Then we used a better piece of technology and were able to see it, and now we are tossing 50 years of science out the nearest airlock.
I could be off on this, but I seem to remember hearing quite a bit about it lately.
Commenting while home from work temporarily (exciting time with the particle accelerators!).
As far as I know, we never found the missing matter and every test to find dark matter turned up goose eggs. As in, by all evidence the missing matter simply is not there. I know there's been some work on alternative theories of gravity, such as this one.
I would be very interested if we found that missing matter.
Edit...
This was what I was thinking of, but it doesn't seem to imply what I was remembering. Oh well. Carry on! :D
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And that's almost as weird as the Quantum Zeno effect. XDSo a watched quantum pot really never boils? That's deeply, truly weird.
It has a 50 percent chance of being either boiled or unboiled at any given moment.
Didn't we recently learn that Dark Matter probably doesn't exist?
We actually never "knew" that it existed.
Here's the situation. We have analyzed the motions of galaxies and after tallying the visible matter i.e. stars, nebulae, etc. we found that we only accounted for 10 percent of the mass needed to keep them from flying apart. So the standard model assumes that 90 percent of the mass is there, but in a form that we can't detect, hence the label "dark matter". This could also include things such as black dwarfs, and black holes that we simply haven't "seen" by them not being close enough to interact with a visible object.
Now there is a thesis for a revised model of gravity that MIGHT take care of the need for the missing 90 percent. What it needs is a means to put it to the test.
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So a watched quantum pot really never boils? That's deeply, truly weird.It has a 50 percent chance of being either boiled or unboiled at any given moment.
You two are this close to inventing the first Nutrimatic Drinks Dispenser, or at least Advanced Tea Substitute. {wanders off searching for common sense particle}
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You two are this close to inventing the first Nutrimatic Drinks Dispenser, or at least Advanced Tea Substitute. {wanders off searching for common sense particle}So a watched quantum pot really never boils? That's deeply, truly weird.It has a 50 percent chance of being either boiled or unboiled at any given moment.
I'm pretty sure Buckminster Fuller died in pursuit of that very particle.
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As in, by all evidence the missing matter simply is not there.
Something is keeping galaxies and clusters from flying apart despite the fact that only one tenth of the mass can be accounted for by cataloguing the visible matter.
So SOMETHING is operating to keep galactic breakups from happening., for now we had assumed that it was matter that we haven't found because it's not visible, hence the term "dark". Now this paper may suggest that it's a misunderstanding in the way we view gravity. Given the implications of that statement, it's going to need some major defense.
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The article is ok, a bit over long perhaps.
I'm not very impressed by this article, I'm afraid. The criticisms of the EmDrive are, IMHO, ill-founded and the primary conclusions of this person is that he should be given lots of money to run a very biased investigation of the claims.
Can anyone here speak to the credibility of this paper? It seems like a where we go from here seminal effort but am myself unable to challenge it adequately.
Oh, I remember this one. Quite old, but still, AFAIK, valid. Basically, it discusses some of the implications of various theories of time travel in light of various theories of QM. Since the time travel theories are completely impractical, and the "theories" of QM are, to the best of our current knowledge, not even testable in theory, the best one can do is say that the theories are or are not coherent with each other.
Fun paper, but not particularly useful at the present time.
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As far as I can tell, the conclusion right now is basically this:
"The EM Drive has been studied by multiple groups for over 10 years, and so far, it seems to have held up. A test in space is appropriate once we can arrange for it. If it still works up there, it's probably worth serious research and development."
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As far as I can tell, the conclusion right now is basically this:
"The EM Drive has been studied by multiple groups for over 10 years, and so far, it seems to have held up. A test in space is appropriate once we can arrange for it. If it still works up there, it's probably worth serious research and development."
It's actually closer to: "The EM Drive has been studied quickly and cheaply by multiple groups with inadequate funding, and to date no conclusive results have been produced either way."
"Scientifically tested" is not a binary thing of either having been done or not. There's a fairly broad spectrum, and sensitivity and accuracy is generally tied in with cost and time. And as previously mentioned, the testing done to date simply proves that more expensive testing would be needed to prove or disprove whether it works.
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I think a test in space qualifies as "more expensive". XD
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It's actually closer to: "The EM Drive has been studied quickly and cheaply by multiple groups with inadequate funding, and to date no conclusive results have been produced either way."
I'm guessing you don't mean it this way, but what you wrote could be read as saying, "Only rich people can do real science."
Also, what makes you say it was done "quickly and cheaply ... with inadequate funding"? I wouldn't know how to tell.