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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!"
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.
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?
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
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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1.21 gigawatts! (Tearing hair out) 1.21 gigawatts!