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Star In A Jar
hyehye writes: "Discover magazine's current issue has a fascinating look at the first astrophysics experiments. By 'experiment,' they mean that actual experiments are being conducted in a lab, rather than just taking observations. What's basically occuring is a ton of lasers are being fired at very tiny objects, producing heat, pressure, and shock waves very similar to the ones produced when stars explode, i.e. go supernova. This is exciting stuff -- producing miniature supernovae in a lab! Take a look!"
It's called fusion. And don't worry about it. It's still 50 years in the future. Ask again in 30 years, and I'll tell you again that it's 50 years in the future.
If tits were wings it'd be flying around.
This is very cool stuff -- people often believe astrophysics is either observational or theoretical. The ability to do experiments is important in verifying the validity of theoretical models and computer simulations.
HOWEVER, note that these experiments are largely concerned with a limited set of physics -- basically radiation hydrodynamics (under the conditions tested, the plasmas are so hot that the radiation pressure is comparable to the gas pressure). Supernovae are essentially hydrodynamical phenomena because the time it takes for a highly supersonic shock to pass through the supernova progenitor is much less than the time it would take for gravity to collapse the progenitor. In astrophysics, many processes (such as star and galaxy formation) are crucially linked not only to radiation hydrodynamics but also to other physics including, critically, self-gravity. It is MUCH more difficult to include self-gravity, because the real self-gravity of the system is totally negligable, and the plasma is charge neutral on a whole (charge densities obey Poisson's equation, just like self-graviting mass densities do).
So this is a very cool start, but it will remain to see if we can ever construct experiments for other kinds of astrophysical systems in the lab.
Bob
Science, like Nature, must also be tamed, with a view turned towards its preservation.
But, IIRC, this comes out of fusion research. Surround a pellet of deuterium with lasers and blast it. Watch it fuse. Everybody gets their name on the paper. They've been doing this for years.
Best Slashdot Co
The latest String Theories, some of which I have been analysing at the Neils Bohr Institute in Kaiserslautern, Germany, show that at high energies and in phasic light, such as produced in an intense laser, normal matter can transmute into dark matter due to resonances.
Washing machines turn socks into dark matter in a similar way, using high energy washic water.
In fact, I studied high energy washic interactions and resonant sockal transduction at the Maytag Repair Guy Institute in Hoboken, New Jersey. Unfortunately, long-term exposure to sudsions has left me impotent.
With that much wattage you could power the Intel Pentium V.
I'm trying to teach myself to set people on fire with my mind... Is it hot in here?
That sounds like a pretty accurate description of what posting that article on Slashdot is doing in discover.com's server room...
Just a few corrections, it takes on the order of 30000 years, not 10 million years for photons to reach the surface of the sun(trust me, i've done the calculations) Also, photons don't experience Brownian motion, they don't have any mass so they can't. The photons are slowed so much because they are continually absorbed at emitted by the atoms making up the convective layer of the sun. Photons take a "random walk" with steps of about 1 cm for the entire radius of the sun.
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Striving to put right what once went wrong, and hoping each time that his next leap, will be the leap ho
http://www.discover.com/june_01/featstar.html
-ted
sucks. Well done, Physics Major, you have scored a perfect coup! You should apply for a job with writing the new Star Trek series.
Here is the corrected version :
(a) Most of the Universe (if you believe in General Relativity) is composed of Dark Energy (70%), not Dark Matter (about 30%). Normal stuff like us is less than 1%.
(b) Neils Bohr is Scandinavian, not German.
(c) Dark Matter accretes, and in current popular models, it does not interact with matter at all (else it won't be "dark")
(d) There is no chance of shooting lasers turning us into exotic matter. Though physicists might wish it does.
(e) What the heck is "phasic" laser beams?
(f) The SETI inference is what convinced me that you are writing a parody. Good job.
SEX!s.e.x.Sex.53X!sex.Si-Ee-Eks
Mode (3) smart-aleck mode. Press * to return to main menu.
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When all you have is a hammer, everything looks like a skull.
A supernova has sufficient mass to heat its core to roughly a trillion degrees as elements fuse through multiple stages. When the core fuses to iron, fusion ceases to be an energy-producing process, and the chain of fusion to higher elements stops. Within the course of a very short time, the iron core cools. The outward radiation pressure stops since the core is no longer radiating, and the outer layers of the star that had been held up by radiation pressure collapse onto the core of the star.
The energy of the impact smashes into the core of the star, compressing its degenerate iron into neutronium as protons and electrons join into neutrons. This phase shift is accompanied by an incredible wave of neutrinos. A neutrino is a kind of ghost particle that interacts weakly with ordinary matter. It would fly through light-years of solid lead without pausing, but there are so many neutrinos released in the phase shift that they form a powerful explosion and blow the collapsing outer shell back off the neutronium core. The turbulence in the exploding gas cloud is so intense that it can cause fusion to atomic weights even higher than iron's. The explosion, while it lasts, briefly outshines the entire rest of the visible universe.
Eventually the expanding gas cloud becomes a nebula and takes place in later generation star and planet formation processes.
Tim
Maybe I should go into astrophysics. Sure, sysadmining gives you godlike control over users, but astrophysics allow you to play with the power of suns.
Curiosity placed the cat in a superimposed alive/dead state. (With apologies to Heisenberg)
Toronto-area transit rider? Rate your ride.
I had a star in a jar in my dorm room years ago, but had to get rid of it. Its gravitational pull was preventing me from moving around much. I did grow some nice muscles, but I'm also horribly disfigured. It was pretty cool though.
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Dark matter accretes. This means that when it comes into contact with normal matter, it transforms it into dark matter too. This is unstoppable.
/. failed to directly link to (as I have just done!) clearly states that dark matter is at the core of the experiment! They have used lasers to compress dark matter to the point where it creates an anti-matter star. While there would certainly be disastrous consequences if this ball of anti-matter were to come into contact with real matter (my first rough sketch comes out to a 350 Megaton yield for each square foot of compressed anti-matter, but feel free to double check) it is made very clear that this pseudo-star (is that what we should call christina aguilera?) is safely contained by the laser containment field.
Um, are you really majoring in physics? Are you just spouting off the top of your head? I'm not sure you know what you're talking about when it comes to dark matter.
First off, the story which
The benefits of this research, namely determing the mass density of the Universe (from the Berkley dark matter paper: "A parameter known as the "mass density" - that is, how much matter per unit volume is contained in the Universe") is far more important than any possible laser containment field leak. Not that any such leak is likely.
Quit with your babbling and stick to the facts. If you want, you can learn more about laser containment fields here.
If I were you I wouldn't bother.
A back-up sun so when ours starts to get old and engulfs us, we can just blow it up and make our own.
Add a whole new sun, besides obvious gravity problems we'd deal with can you imagine how great things would grow?
Two-story target chamber lazer gun pointed right at, um, France! Come on, you can't say you didn't think it too...
spacefem.com
First a bit of background. Commercial nuclear powerplants and naval propulsion plants operate on the principle of nuclear fission, the splitting of very heavy atoms to yield thermal energy, which heats steam, which turns an electric turbine or propeller shaft. What the_crowbar is talking about is nuclear fusion, the slamming together of very light atoms, i.e. heavy hydrogen or helium, in a chamber of superheated (in a star's case, superdense) plasma, thus heating steam and turning a turbine.
There was a major international experiment called the International Thermonuclear Experimental Reactor, or ITER. A russian-invented device called a tokamak, or magnetic bottle, can be used to contain plasma in a doughnut-shaped chamber. These are in use at several research labs and universities, including Harvard University and Lawrence Livermore Labs. The ITER was concieved as a prototype reactor to spearhead the way for commercially run nuclear fusion electricity plants, as proof-of-concept. The reactor was expected to cost over $4 TRILLION dollars. Therefore, the U.S. Congress, not wanting to any more money than necessary to get re-elected, withdrew U.S. support in 1998, and the project is expected to fail without U.S. funding. Go to Scientific American Magazine for more information on this project.
1.21 gigawatts! (Tearing hair out) 1.21 gigawatts!