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Lasers Approach Their Ultimate Intensity Limit
Flash Modin writes "Death Star style superlasers? Don't bet on it. High-power lasers currently in development appear to be nearing the theoretical laser intensity limit, according to new research set to be published in the journal Physical Review Letters. Ultra-high-energy laser fields can actually convert their light into matter as shown in the late '90s at the Stanford Linear Accelerator (SLAC). This process creates an 'avalanche-like electromagnetic cascade' (also known as sparking the vacuum) capable of destroying a laser field. Physicists thought it might be a problem for lasers eventually, but this work indicates the technology is much closer to its limit than researchers believed. A preprint is available here."
Creating light from matter is rather ordinary in terms of physics, as can be seen in nuclear explosions
Or even running out of lighter fluid.
The SLAC experiment was just a singular event, but as lasers reach higher intensities the electric fields produced will increase as well and the team says that when they reach a critical intensity a cascade effect will occur as a result. The electron-positron pair is accelerated by the laser field itself at such high energies that they emit photons capable of spawning new pairs and continuing the process.
Maybe that's how the death star works? Besides, it isn't explicitly stated anywhere in the movies that the death star is a laser.
Also, they're not talking about a single laser, they're talking about colliding two laser beams.
Free Martian Whores!
Have they considered relabeling their laser intensity dials so they go up to 11?
"Death Star style superlasers? Don't bet on it."
Uh, you mean a bunch of laser beams that come out straight, stop for a fraction of a second, turn a few degrees and then join up and all go off in the same direction?
I wasn't exactly holding my breath for that, anyway!!
I find your lack of faith disturbing.
maybe we just need to hold them differently?
the preceding post was not spell checked... suck it.
Energy converts to matter, and matter to energy, all the time. Check out Feynman diagrams for many examples. Particle colliders are machines built for the purpose of converting energy into matter. When particles collide, some of their energy converts to various forms of matter.
What a fool believes, he sees, no wise man has the power to reason away.
Henchman: "Professor, I've increased the laser's power to a new incredible limit, and something remarkable has happened. It is creating new matter! I can tune the beam to create any matter in any configuration we need!"
Professor: "Darn. We needed a big laser. Oh well, throw it all out, that was a dead end."
- For the complete works of Shakespeare: cat
But it is energy that was stored in a either a chemical bond, or an electron state. Matter does not disappear, it is just electrons rearranging their orbits. If you count all the protons, neutrons and electrons before and after the chemical reaction, they're all still there.
Those who can, do. Those who can't, sue.
Both nuclear and chemical reactions destroy matter, if you can call that destroying matter.
In a chemical reaction, electrons change states. In an exothermal chemical reaction, the energy of those electron states is lower than the energy of the electron states before the reaction, and energy is released in another form (photons, kinetic energy, etc.). If you count the neutrons, protons, and electrons, they're all still there. But mass has been lost, because the binding energy of the electrons counts in the mass of the molecule. (In the reaction, binding energy was lost and converted to another form. Energy is mass.) However, chemical binding energy is tiny compared to the energy in the rest mass of protons, neutrons, and electrons.
In a nuclear reaction (fission and fusion), the states of nucleons (neutrons and protons) also change. Again, if you count the neutrons, protons, and electrons, the same ones present before are present after. (Sometimes they change form, like n p + e.) But mass has been lost, because the binding energy between the nucleons counts in the mass of the atom. (In the reaction, binding energy was lost and converted to another form. Energy is mass.) Nuclear binding energy is still small compared to energy in rest mass, but it's a lot bigger than chemical binding energy.
True, but if you could actually measure the mass of the butane molecule with enough precision, you would find that it is more massive than the constituent atoms alone. This extra mass (m=E/c^2) is actually due to the potential energy stored in the bonds.
Unfortunately, that opening paragraph is horribly written. The rest of the entry is better, and gives an accurate though terse description of the problem. Before the 1940s, many aeronautical engineers believed -- quite rightly, givem the technology of the day -- that they couldn't design a plane that would hold together while passing Mach 1. Nobody ever claimed that it was physically impossible to fly faster than sound, and of course such a claim would have been absurd given that there were plenty of examples of things that did just that (e.g. bullets.) Serious attempts to build a supersonic airplane began in the 1930s, and by the start of WW2 everyone working in the high-performance aircraft field knew it was possible, they just didn't know exactly how to do it.
In short, it was an engineering problem, not a scientific one. This is completely different from limitations which are founded, as far as we can tell, not in the state of technology but in the laws of nature.
If out current understanding of the limiting natural laws turns out to be wrong, great -- I'd love to see a Death Star just as much as any nerd would. But don't bet on it. The fact that the X-1 flew no more means that we'll someday have faster-than-light starships with planet-destroying laser weapons than the existence of the internal combustion engine implies that perpetual motion machines are right around the corner.
The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
Chemical energy is energy and is matter too. If you measure 8 tons of oxygen and 2 tons of hydrogen (hopefully I got my stochiometry right), and let them react, and cool off, and measure the total weright afterward you will find it changed.
Mass energy equiavelence, scroll to "Binding energy and the "mass defect".
C. Sagan : A demon haunted world:
http://www.amazon.com/gp/product/0345409469/
visit randi.org
The researchers at the SLAC need to recheck their results, because Andy Schlafly, Conservapedia founder and a Eagle Forum "University" instructor has noted that E=mc^2 is a liberal plot.
Yet more experimental evidence that reality has a "liberal" bias.
Luke, help me take this mask off