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Is FTL travel just around the corner?

- - - - - clickbait title no calling sentynel

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#1
wistd

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Boffins create substance with negative mass.

 

http://www.bbc.co.uk...onment-39642992


We've already boiled communication down to acronyms, emoticons and shrtnd sntnces, all of which are simply more efficient ways of transmitting the PLEASE AUTHENTICATE MY EXISTENCE signal from the fragile core of our souls out into the wider world. Maybe the next stage is to reduce it all down to a single noise. I'd favour a short, electronic beep, not unlike the noise emitted each time Pac-Man eats a dot.

#2
Kris

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Someone has blown the Sentynel horn.
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#3
Readout

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"Physicists have created a fluid with "negative mass", which accelerates backwards when pushed."

 

...

 

"Scientists today have announced a brand new FTL drive. Unfortunately, the pilot testing it accidentally knocked the rear-view mirror out of place and reversed into an inter-space police ship because he couldn't see where he was going. When asked why they didn't just install the engine in backwards, NASA was reported as mumbling quietly about it just simply being wrong. Fortunately, leading manufacturers have announced that they will be placing a camera in the boot in the next model spaceship, meaning that pilots can see where they are warping on the sat nav screen."


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The "L" stands for "Value".

 

Nobody can hear the sarcasm in your voice when you type. Which is why they invented teal.

 

Readout's list of done-to-death-and-beyond topics: Feminism, Sexism, Social Justice Warriors, Racism, Trump vs Clinton.


#4
Sentynel

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Another day, another set of hilariously misleading science news reporting.

 

The key word helpfully dropped by the reporting here is "effective". The first line of the abstract reads as follows: "A negative effective mass can be realized in quantum systems by engineering the dispersion relation." We're very much not talking about the mass in the strict inertial/gravitational mass sense; this is not a paper about tachyons, antigravity, or anything else similarly exciting implied by true negative mass.

 

The concept of effective mass really comes from saying "Newton's second law states F = ma; however, there are plenty of weird real systems in which that simple relation does not hold. I have one of those weird systems; I'm going to call the coupling constant between F and a in this case the 'effective mass' because it replaces m in Newton's second law". So in this case, they've produced a system where the direction of a is actually opposite to F, which gives you a negative effective mass. But it doesn't bear any particular relationship to actual mass. What's really going on here is just a quirk of wave mechanics (remember, dealing with quantum systems, everything is a wave); it's certainly a cool finding if you're a condensed matter physicist, but it's in no way worthy of the breathless headlines.

 

I dug up a prepub copy of the paper on arXiv, and the first line of the abstract reads "Negative mass can be realized in quantum systems by engineering the dispersion relation." Note that "effective" is only introduced in the publication version of the abstract, presumably due to a reviewer saying "don't you think that's a bit misleading". I suspect it's been deliberately spun in press releases to elide the distinction between effective mass and actual mass, and therefore get media attention. Sigh.


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#5
Presea

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Shoot an object with a velocity of 50% the speed of light out of a spaceship flying at 51% the speed of light.

 

FTL travel solved :D

 

obviously doesn't work that way, but still


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#6
Kris

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Sentynel came out to answer, congratulations everyone spring has finally arrived and we don't have another eternity of hilarious Bill Murray antics!

On second thought I'll take Bill Murray.

#7
Axeman

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Another day, another set of hilariously misleading science news reporting.

 

The key word helpfully dropped by the reporting here is "effective". The first line of the abstract reads as follows: "A negative effective mass can be realized in quantum systems by engineering the dispersion relation." We're very much not talking about the mass in the strict inertial/gravitational mass sense; this is not a paper about tachyons, antigravity, or anything else similarly exciting implied by true negative mass.

 

The concept of effective mass really comes from saying "Newton's second law states F = ma; however, there are plenty of weird real systems in which that simple relation does not hold. I have one of those weird systems; I'm going to call the coupling constant between F and a in this case the 'effective mass' because it replaces m in Newton's second law". So in this case, they've produced a system where the direction of a is actually opposite to F, which gives you a negative effective mass. But it doesn't bear any particular relationship to actual mass. What's really going on here is just a quirk of wave mechanics (remember, dealing with quantum systems, everything is a wave); it's certainly a cool finding if you're a condensed matter physicist, but it's in no way worthy of the breathless headlines.

 

I dug up a prepub copy of the paper on arXiv, and the first line of the abstract reads "Negative mass can be realized in quantum systems by engineering the dispersion relation." Note that "effective" is only introduced in the publication version of the abstract, presumably due to a reviewer saying "don't you think that's a bit misleading". I suspect it's been deliberately spun in press releases to elide the distinction between effective mass and actual mass, and therefore get media attention. Sigh.

 

I think I love you physics. Do you think physics can join us in the new forums once we migrate?


"The Germans dive deeper – but they come up muddier"

Wickham Steed


#8
Sentynel

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I think I love you physics. Do you think physics can join us in the new forums once we migrate?

I suppose I shall go where the threads about silly science news articles go.


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