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panrider_uk |
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panrider_uk World Chat Champion
Joined: 23 Sep 2007 Karma :
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Posted: 16:31 - 19 Apr 2017 Post subject: Negative mass |
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I'm wondering how this can be made into a tractor beam ____________________ Current bike: Honda ST1100 |
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CaNsA |
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CaNsA Super Spammer
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Rogerborg |
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Rogerborg nimbA
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oldpink |
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oldpink World Chat Champion
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Posted: 17:58 - 19 Apr 2017 Post subject: |
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really interesting
raises a lot of points like does it have negative energy (E=MC2)
C2 is a constant (for now) so if Mass is negative then Energy would need to be negative ____________________ I have become comfortably numb
Theory & hazard 24-may 2016, CBT 8th June 2016, MOD 1 2nd Aug 2016 Mod 2 2nd-Nov 2016 - Current bike CBR 600 RR |
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Hong Kong Phooey |
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Hong Kong Phooey World Chat Champion
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WD Forte |
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WD Forte World Chat Champion
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oldpink |
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oldpink World Chat Champion
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Rogerborg |
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Rogerborg nimbA
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stinkwheel |
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stinkwheel Bovine Proctologist
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Posted: 11:09 - 20 Apr 2017 Post subject: |
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My understanding is it's all about entropy.
It's nearly at zero enthalpy (zero kelvin) and is trying to reach that lowest possible energy state. As soon as you apply energy, it tries to get rid of the ordering that has ensued.
Theoretically, if you put a Bose-Einstein condensate in a beaker, it would crawl out up the sides so it could lie on the floor.
You also have to factor in the energy that is being expended maintaining it at such a low temeprature. By applying energy to the BEC, you apply enthalpy to the system, so it will either begin to change state or the energy has to be given up (ie, it needs to be cooled to remain as a BEC. Poking it would otherwise warm it up).
The process of cooling is actually taking heat energy and moving it elsewhere, usually dissipating it more widely. So the "negative" energy you got from the matter is actually being blown out of a massive heat exchanger somewhere. ____________________ “Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles. |
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oldpink |
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oldpink World Chat Champion
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Rogerborg |
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Rogerborg nimbA
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Posted: 12:53 - 20 Apr 2017 Post subject: |
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Mmm, like how the Hubble Constant isn't. ____________________ Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike |
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oldpink |
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oldpink World Chat Champion
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Andy_Pagin |
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Andy_Pagin World Chat Champion
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Lord Percy |
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Lord Percy World Chat Champion
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Posted: 14:07 - 20 Apr 2017 Post subject: |
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stinkwheel wrote: | My understanding is it's all about entropy.
It's nearly at zero enthalpy (zero kelvin) and is trying to reach that lowest possible energy state. As soon as you apply energy, it tries to get rid of the ordering that has ensued.
Theoretically, if you put a Bose-Einstein condensate in a beaker, it would crawl out up the sides so it could lie on the floor.
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Kind of, but there isn't any ordering to get rid of because bosons can exist all together in the very lowest energy state. It doesn't doesn't flow up the beaker to escape 'order', it flows up because it has zero viscosity i.e. is frictionless, so nothing is preventing it moving up the sides. Consider that all fluids have a meniscus - superfluid going up the sides of the beaker is just the ultimate, unhindered version of that.
Quote: |
You also have to factor in the energy that is being expended maintaining it at such a low temeprature. By applying energy to the BEC, you apply enthalpy to the system, so it will either begin to change state or the energy has to be given up (ie, it needs to be cooled to remain as a BEC. Poking it would otherwise warm it up).
The process of cooling is actually taking heat energy and moving it elsewhere, usually dissipating it more widely. So the "negative" energy you got from the matter is actually being blown out of a massive heat exchanger somewhere. |
Funnily enough, just yesterday I said on another thread that some of the material I've studied lately is useless - " 'Totally useless' would be the quantum photonics stuff I'm learning." - but quantum photonics plays a big part here. The Bose-Einstein condensate is made via laser cooling, which means photons are coaxed out of the atom with the laser field set such that the photons that were lost can't be regained, because the doppler effect of the photons against the laser means most incoming photons will have less energy than the outgoing ones, hence energy (and therefore temperature) decreases. The energy that goes into running the laser is completely separate from the photon energy being removed by the setup.
To me the term 'negative mass' (or negative energy) is too misleading, specially given how every popular science blog is claiming it would be possible to literally push an object of negative mass and have it move against that push. The correct term is negative effective mass, which is a way of understanding how mass (normal garden variety 'mass') responds to external inputs. The effective mass can vary for lots of reasons, and does so with necessity in all condensed matter physics (semiconductors being the big one). For the effective mass to be negative is not a sign of its entire physical presence being some spooky mystical reverse-physical thing, it's just an effective mass that is recorded as negative when prodded.
It's fairly telling that there's isn't a word of excitement about this on Physics Forums, whereas the popular science blogger world is going berserk because, "Woooooah impossible negative mass!"
oldpink wrote: | current theorys are looking at the speed of light just after the big bang when it may have been a lot slower |
Lots of things will have had different properties in the moments just after the big bang, but it's a matter of scaling. The speed of light is probably always changing but we'll always witness and record it as having the same rate, because we're part of the same universe that light propagates through. Cosmic microwave background radiation is a known remnant of the big bang but that propagates at c, even if c was different when it was created.
This is why it's called a universal constant. Unlike, for example, the rate of expansion of the universe which is different now from what it was at the very start. |
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dydey90 |
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dydey90 World Chat Champion
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Rogerborg |
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Rogerborg nimbA
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colink98 |
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colink98 Could Be A Chat Bot
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Lord Percy |
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Lord Percy World Chat Champion
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Posted: 15:56 - 20 Apr 2017 Post subject: |
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Rogerborg |
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Rogerborg nimbA
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Posted: 16:06 - 20 Apr 2017 Post subject: |
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Is that how gyroscopicopters work as well? ____________________ Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike |
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Lord Percy |
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Lord Percy World Chat Champion
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el_oso |
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el_oso World Chat Champion
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Fisty |
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Fisty Super Spammer
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Posted: 18:30 - 23 Apr 2017 Post subject: |
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This thread.
https://m.popkey.co/574b46/WxVke.gif ____________________ Quietly and consistently taking the piss.
TL1000R | Hayabusa | ZXR400 | TL1000S | Bandit 400 V
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GhostRider |
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GhostRider World Chat Champion
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Old Thread Alert!
The last post was made 6 years, 341 days ago. Instead of replying here, would creating a new thread be more useful? |
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