5 ms·

China on brink of laser-matter breakthrough – Asia Times

33 points by mrfusion 5y ago

mensetmanusman 5y ago
It’s a China/UK collaboration. Andrei Seryi, director of the John Adams Institute at Oxford University, said: “It’s breathtaking to think that things we thought are not connected, can in fact be converted to each other: matter and energy, particles and light. Would we be able in the future to convert energy into time and vice versa?” - This is a fun thought experiment. If spacetime is energy, could we create spacetime with energy, or destroy some spacetime for energy…
andrekandre 5y ago
In any case, both UK and Chinese scientific teams are not on the verge of a machine that can create everyday objects from a sudden blast of laser energy — so far, that reality only exists in science fiction. assuming 100% effeciency, it would still take 1kg of matter converted to some kind of energy (power generation) to light to get that 1kg back again in a different form... is that correct? and i guess if you wanted to get anti-matter... would this be more efficient way thanother current methods?
- lumost 5y ago
  Given current knowledge of physics, 1kg of energy would create .5 kg of matter and .5 kg of antimatter. The apparatus would need to immediately separate the two to prevent an extremely large explosion. Presumably there is some unknown process which either favors matter production or sequesters antimatter as this occurred during the big bang.
  - andrekandre 5y ago
    The apparatus would need to immediately separate the two to prevent an extremely large explosion. right. im sure the physists working on this project know that, but im curious how much of a risk 100,000 matter/anti-matter pairs would make... i guess not much?
    - grozzle 5y ago
      200000 hydrogen atoms has a mass of 201600 atomic mass units (about three haemoglobin molecules), which by e=mc² is about 188 TeV (tera electron volts), which is about 30 microJoules, or about 2% of the energy needed to register a key press on a mechanical keyboard.
      - andrekandre 5y ago
        thats amazingly cool way to put it, thanks ^^
    - grozzle 5y ago
      (can't edit first comment, sorry) 1kg of mass to energy (assuming every single particle met a corresponding antiparticle) would release a little over half the energy of the Krakatoa volcano eruption, similar to a 21 megaton bomb, so around the upper end of fusion bombs. Helium is about 99.5% the mass of the hydrogen that goes into it, so I guess those big fusion bombs must produce about 200kg of helium?
      - andrekandre 5y ago
        wow interesting, when you say "upper end" it means the effeciency of matter → energy conversion is at the upper end of fusion, or 1kg of anti-matter would have the same power of an upper end fusion? either way super cool
        grozzle 5y ago
        I meant that 21 megatons is big enough to be among what the USA and USSR would have called their biggest H-bombs. (megaton, to be clear, is not a measure of mass when talking about bombs, it's a measure of energy released - a 1 megaton bomb is equivalent to the energy released by a million tons of TNT, if such a volume could be detonated)
hliyan 5y ago
This paper suggests that such a setup can generate a non-trivial amount of electron-positron pairs: "Matching experimental parameters to current-generation facilities, Monte Carlo simulations suggest that this scheme is capable of producing of the order of 10^5 Breit–Wheeler pairs in a single shot." [1] https://www.nature.com/articles/nphoton.2014.95 https://www.nature.com/articles/nphoton.2014.95
davidhyde 5y ago
And that’s why we don’t see aliens. All of them figure out how to make really powerful lasers before leaving their home planet ;)
- failwhaleshark 5y ago
  So no need to build a Death Star. They all went "whoops" femtoseconds before said event.

33 points by mrfusion 5y ago

It’s a China/UK collaboration. Andrei Seryi, director of the John Adams Institute at Oxford University, said: “It’s breathtaking to think that things we thought are not connected, can in fact be converted to each other: matter and energy, particles and light. Would we be able in the future to convert energy into time and vice versa?” - This is a fun thought experiment. If spacetime is energy, could we create spacetime with energy, or destroy some spacetime for energy…

andrekandre 5y ago

In any case, both UK and Chinese scientific teams are not on the verge of a machine that can create everyday objects from a sudden blast of laser energy — so far, that reality only exists in science fiction. assuming 100% effeciency, it would still take 1kg of matter converted to some kind of energy (power generation) to light to get that 1kg back again in a different form... is that correct? and i guess if you wanted to get anti-matter... would this be more efficient way thanother current methods?

lumost 5y ago
Given current knowledge of physics, 1kg of energy would create .5 kg of matter and .5 kg of antimatter. The apparatus would need to immediately separate the two to prevent an extremely large explosion. Presumably there is some unknown process which either favors matter production or sequesters antimatter as this occurred during the big bang.
- andrekandre 5y ago
  The apparatus would need to immediately separate the two to prevent an extremely large explosion. right. im sure the physists working on this project know that, but im curious how much of a risk 100,000 matter/anti-matter pairs would make... i guess not much?
  - grozzle 5y ago
    200000 hydrogen atoms has a mass of 201600 atomic mass units (about three haemoglobin molecules), which by e=mc² is about 188 TeV (tera electron volts), which is about 30 microJoules, or about 2% of the energy needed to register a key press on a mechanical keyboard.
    - andrekandre 5y ago
      thats amazingly cool way to put it, thanks ^^
  - grozzle 5y ago
    (can't edit first comment, sorry) 1kg of mass to energy (assuming every single particle met a corresponding antiparticle) would release a little over half the energy of the Krakatoa volcano eruption, similar to a 21 megaton bomb, so around the upper end of fusion bombs. Helium is about 99.5% the mass of the hydrogen that goes into it, so I guess those big fusion bombs must produce about 200kg of helium?
    - andrekandre 5y ago
      wow interesting, when you say "upper end" it means the effeciency of matter → energy conversion is at the upper end of fusion, or 1kg of anti-matter would have the same power of an upper end fusion? either way super cool
      - grozzle 5y ago
        I meant that 21 megatons is big enough to be among what the USA and USSR would have called their biggest H-bombs. (megaton, to be clear, is not a measure of mass when talking about bombs, it's a measure of energy released - a 1 megaton bomb is equivalent to the energy released by a million tons of TNT, if such a volume could be detonated)

hliyan 5y ago

This paper suggests that such a setup can generate a non-trivial amount of electron-positron pairs: "Matching experimental parameters to current-generation facilities, Monte Carlo simulations suggest that this scheme is capable of producing of the order of 10^5 Breit–Wheeler pairs in a single shot." [1] https://www.nature.com/articles/nphoton.2014.95 https://www.nature.com/articles/nphoton.2014.95

davidhyde 5y ago

And that’s why we don’t see aliens. All of them figure out how to make really powerful lasers before leaving their home planet ;)

failwhaleshark 5y ago
So no need to build a Death Star. They all went "whoops" femtoseconds before said event.