Slashdot Mirror
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!"
DON'T FEED THE TROLLS, DAMMIT!
Give your heads a shake, people. Recognize a joke when you see one. "Curiousity Killed the Cat" is a blatant chain-yank, and a half-dozen of you were dumb enough to fall for it.
How To Recognize The Troll
* there are lots of adjectives: "once lush planet," "reckless desire," and the like.
* there's a personal disclaimer: "don't get me wrong."
* there's often a reference to religion: "[better to] study scripture."
But the biggest indicator is that it's every damn sentence is over-the-top hyperbole.
Don't get me wrong: I appreciate a good luddite-like troll. But, please, don't feed the trolls!
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Don't like it? Respond with words, not karma.
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.
Bullshit. Einstein was in religious terms an atheist, and insofar as he said things like "I don't belive God plays dice with the universe" etc. he was not talking about a "personal God" in any religious sense. I suspect the same is true of Galileo. As for Sir Isaac, he was well known as a mystic and dabbler in secret societies, so his views were certainly not "orthodox", protestant though they may have been.
Here are some quotes to make my point about Einstein:
It was, of course, a lie what you read about my religious convictions, a lie which is being systematically repeated. I do not believe in a personal God and I have never denied this but have expressed it clearly. If something is in me which can be called religious then it is the unbounded admiration for the structure of the world so far as our science can reveal it.
[Albert Einstein, 1954, from Albert Einstein: The Human Side, edited by Helen Dukas and Banesh Hoffman, Princeton University Press]
What I see in Nature is a magnificent structure that we can comprehend only very imperfectly, and that must fill a thinking person with a feeling of humility. This is a genuinely religious feeling that has nothing to do with mysticism.
[Albert Einstein]
You will hardly find one among the profounder sort of scientific minds without a religious feeling of his own. But it is different from the religiosity of the naive man. For the latter, God is a being from whose care one hopes to benefit and whose punishment one fears; a sublimation of a feeling similar to that of a child for its father, a being to whom one stands, so to speak, in a personal relation, however deeply it may be tinged with awe. But the scientist is possessed by the sense of universal causation... There is nothing divine about morality; it is a purely human affair. His religious feeling takes the form of a rapturous amazement at the harmony of natural law, which reveals an intelligence of such superiority that, compared with it, all the systematic thinking and acting of human beings is an utterly insignificant reflection... It is beyond question closely akin to that which has possessed the religious geniuses of all ages.
[Albert Einstein, Mein Weltbild, Amsterdam: Querido Verlag, 1934]
I received your letter of June 10th. I have never talked to a Jesuit priest in my life and I am astonished by the audacity to tell such lies about me. From the viewpoint of a Jesuit priest I am, of course, and have always been an atheist.
[Albert Einstein to Guy H. Raner Jr, July 2, 1945, responding to a rumor that a Jesuit priest had caused Einstein to convert from atheism. Article by Michael R. Gilmore in Skeptic magazine, Vol. 5, No. 2, 1997]
I have repeatedly said that in my opinion the idea of a personal God is a childlike one. You may call me an agnostic, but I do not share the crusading spirit of the professional atheist whose fervor is mostly due to a painful act of liberation from the fetters of religious indoctrination received in youth. I prefer an attitude of humility corresponding to the weakness of our intellectual understanding of nature and of our own being.
[Albert Einstein to Guy H. Raner Jr., Sept. 28, 1949, from article by Michael R. Gilmore in Skeptic magazine, Vol. 5, No. 2, 1997]
The idea of a personal God is an anthropological concept which I am unable to take seriously.
[Albert Einstein, letter to Hoffman and Dukas, 1946]
I do not believe in the God of theology who rewards good and punishes evil.
[Albert Einstein, as quoted in a memoir by Life editory William Miller in Life, May 2, 1955]
I do not believe in immortality of the individual, and I consider ethics to be an exclusively human concern with no superhuman authority behind it.
[Albert Einstein: The Human Side, edited by Helen Dukas and Banesh Hoffman, and published by Princeton University Press.]
I cannot conceive of a God who rewards and punishes his creatures, or has a will of the kind that we experience in ourselves. Neither can I nor would I want to conceive of an individual that survives his physical death; let feeble souls, from fear or absurd egoism, cherish such thoughts. I am satisfied with the mystery of the eternity of life and with the awareness and a glimpse of the marvelous structure of the existing world, together with the devoted striving to comprehend a portion, be it ever so tiny, of the Reason that manifests itself in nature.
[Albert Einstein, The World as I See It]
http://atheism.about.com/religion/atheism/library/ quotes/bl_q_AEinstein.htm
7 November 2006: The day Americans realized corruption and incompetence weren't addressing 11 September 2001
Yeah, well, Einstein was demonstrably wrong, and not too great a scientist if he wanted to rely on calculations without pursuing experimentation to verify theoretical results.
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.
i assume you've heard of cosmic rays? Higher energy than anything we can create in the lab. Please extend your disseration to explain why they haven't caused this 'dark matter accretion' and whiped us out during the last, oh, 5 BILLION years or so.
Oh yeah - I forgot. You're a troll. nice try. Too bad the mods are smoking crack today.
>>Nobody ever unravelled the basic fabric of
>>spacetime by studying Scripture.
Yup - but lots of nice people burnt at the stake.
Good thing the catholics finally worked out that whole 'sun round the earth thing'. Only took em 300 years.
So how are things in Kansas?
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.
The pressures and densities of the sun are so great, that photons (released as byproducts of fission in the sun's core) takes on average about 10 million years before they reach the surface (10 minutes to get to the earth from there). This is because of the random Brownian motion of the photons route.
Someone you trust is one of us.
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...
http://www.discover.com/june_01/featstar.html
-ted
(If there are any nuclear engineers in the audience, please feel free to correct me as this is from memory)
Ordinary nuclear reactors are fission reactors -- they split heavy nuclei into two lighter nuclei and a bit of energy. The most common fissionable material is Uranium-235, which as you might expect is extremely radioactive, and the "nuclear ash" (the lighter elements which result from fission) are also typically radioactive.
Nuclear fusion is the opposite process -- combining lighter nuclei into heavier ones. The sun produces its energy by fusing four hydrogen nuclei (otherwise known as protons) into a single helium nucleus (otherwise known as alpha particles: two protons and two neutrons). The four constituent protons are just a tad heavier than an alpha particle, and the extra mass is turned into energy.
Nuclear fusion in the lab (which *has* been done before, many times) doesn't follow the exact same process. It typically uses deuterium and tritium, which are hydrogen-2 (a proton and a neutron) and hydrogen-3 (a proton and two neutrons), respectively. Tritium is radioactive.
So while nuclear fusion doesn't have to involve radioactive substances (as evidenced by solar fusion), so far I don't think anybody has gotten away from them. Admittedly, though, fusion will still be infinitely cleaner than fission once somebody manages to generate a useful amount of power from it.
ZFS: because love is never having to say fsck
If this was true, why aren't all stars "dark matter"? Our own atoms (above Iron in weight) were forged in a supernova. By your "facts", we should all be dark matter now.
If you are really a physics major, Mr. "Physics Major", I would have expected you to know this.
What you're reffering to is the process of nuclear FUSION. Modern nuclear reactors are based on the concept of nuclear FISSION, which is a process where energy is released when a large atom is split into smaller atoms (and a few neutrons). Fusion is where two small atoms are fused together to get energy (and no, this isn't a conservation of energy problem). Much work has been done in the area of nuclear fusion, but as of yet a commercially viable fusion reactor has not been created.
However, a supernovae is not just any fusion reaction. All stars go through fusion their entire lives. It's what keeps them heated. But a supernovae happens when a star starts running out of fuel. I don't know the exact process (I'm sure someone around here does).
So while this supernovae-in-a-can is very cool, it's separate from energy generation as a whole.
Save a life. Eat more cheese
So there I was, juggling apples and small animals, when I accidentally bit into the wrong one...
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.
An astro prof here (CMU) has a neat classroom demo that he does during the lesson on supernovae which he calls star in a jar.
He mixes a two compontent apoxy in a clear plastic cup using way too much hardener (i.e. 5 times what the directions say). Be sure to do this on a large piece of metal you don't care about and do it outside cause it makes quite a mess and smells.
Basically what happens is that the apoxy undergoes an exothermic reaction, but due to the excessive amount of catalyst present, more heat is created than can be dissapated through the viscous flow of the apoxy (don't forget the apoxy is hardening the whole while). Eventually the apoxy heats enough to melt the cup, crack the hardened apoxy, smoke, etc. This gets the entire class's attention because he mixes the apoxy at the beginning of the class and proceeds to lecture for a while before anything begins to happen. It takes a little while.
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When all you have is a hammer, everything looks like a skull.
Hopefully this won't fall in to the wrong hands....muahahahahaha! *cough* excuse me...
How Jaded Are You?
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.
Um, yeah, lots of people thought of the consequences -- or else they wouldn't be doing it. This isn't the wonderful hodge podge corporate america pseudo science we're all used to, putting mascara on a cat's ass to see if it causes polyps. These are the world's greatest thinkers testing hypothesises. Are you suggesting they didn't consider the ramifications of their actions? Don't be naive.
Creating a black hole the size of an atom has little to no effect on the planet because its mass is meager compared to everything else around it -- meaning practically no gravitational forces. Find a way to contain it and its subatomic event horizon and you've got the coolest vacation home for your sea monkeys ever. Remember: gravity doesn't change just because you're a singularity; a kilogram with no volume is still a kilogram, still a negligible factor in the universe, and if you dropped it it wouldn't have much affect on the earth or the people around it.
As for creating micro supernovas...they're super small, dude, and only as powerful as the lasers involved. You'll see more possibility for an environmental disaster in your average Hollywood movie than in this experiment. I know, I know...your high school science teacher said that supernovas are bad. But this is a really freaking small one, controlled by people who know what they're doing and in an expensive experiment that had to be reviewed and rereviewed a dozen times over before it could be approved for the extensive grants and equipment could be divvied up. If a slashdotter can point out flaws that these eggheads can't find, well then I just lost my faith in the scientific method.
Hey freaks: now you're ju
You don't like dark matter because you are trying to keep the black man down.
Hey freaks: now you're ju
Ever hear of a hydrogen bomb? This experiment is basically a hydrogen bomb but shrunk down to a more controllable size. Yeah it can screw things up, but we've already got treaties controlling these things.
If god had intended you to be naked, you would have been born that way.
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!
There are a lot of explanations going around this thread about how core collapse supernovae occur. Some good, some terrible, none quite right. Rather than correct what's been said, I'll instead point y'all to a few of the sources of real info out there.
A good place to start is the NASA Observatorium page on Stellar Evolution and Death
A friend in the business maintains a page full of links to SN pages. Many of these are links to research groups, but there are also links to general education and image catalogs.
BTW, in case you don't believe that I know of what I speak, follow this link