846Views169Replies

Author Options:

Scientists plan to ignite tiny man-made star Answered

From www.telegraph.co.uk:

"While it has seemed an impossible goal for nearly 100 years, scientists now believe that they are on brink of cracking one of the biggest problems in physics by harnessing the power of nuclear fusion, the reaction that burns at the heart of the sun.

In the spring, a team will begin attempts to ignite a tiny man-made star inside a laboratory and trigger a thermonuclear reaction.

Its goal is to generate temperatures of more than 100 million degrees Celsius and pressures billions of times higher than those found anywhere else on earth, from a speck of fuel little bigger than a pinhead. If successful, the experiment will mark the first step towards building a practical nuclear fusion power station and a source of almost limitless energy.

Full article.

This is big medicine, because while we have (more or less) successfully harnessed the power in nuclear fission, we've yet to find a method of using nuclear fusion for power (outside of experimental/weaponry uses). It is important to note, however, that this initial experiment, while big, won't be powering your home or office just yet-even if it does work, there's still quite a lot that would have to be done to build a nuclear fusion power plant.

Still, it's heady stuff, the energy source of dreams-a world powered by nuclear fusion fueled by hydrogen, one of the most abundant elements in the universe-only now that dream is looking like it could, possibly, maybe, eventually, become reality.

And now, a word from our sponser resident particle physicist:

The NIF at Livermore uses small (BB-sized) pellets of liquid hydrogen (technically a deuterium-tritium mixture) encased in a shell.

The pellet is illuminated by a terawatt laser split into 192 sub-beams all focused on a poiint. The outer shell of the pellet is vaporized and a shockwave compresses the hydrogen to the point where it should start fusion.

The whole process is over in roughly a microsecond. If you keep dropping pellets into the chamber, then you get a series of pulses, but as soon as you stop, everything shuts down.

The NIF (like the NOVA laser before it) is being run at a weapons lab, because the kind of fusion it can do (individual microsecond pulses) is most useful for studying the physics underlying thermonuclear weapons. It is probably not a viable technology for continuous power-generation fusion, but it is necessary for understanding how to make that sort of system work.

Discussions

I went to the presentation about it... i've got some data; it takes 20bn/sec for all the lasers to be fired and for the beams to reach the target In costs $5 to fire the laser the expected output is 20-25 times the power input the lasers will be fired into a target the size of a pencil eraser here's a worksheet i recieved

saturday.jpg

Wow! This will be probably the smallest star in the universe! - and is very close the surface of a planet...

If it is under 20 miles of rock it may not harm the planet.

Well A-bombs were tested undergrond for safety to the enviroment and the life outside. So Deep is a good idea.

However, that could trigger earthquakes...

Yes, they were tested a few hundred feet underground, both for safety (ironically), and because it is far easier to set up instrumentation when you can mount it on rock walls.

20 miles!?!?!?!?!? How the hell did they manage to get that far down???? I heard that the deepest drill bit hole is about 8 miles deep.

What does that mean exactly.

A little actual research would take you a very long way. The deepest mine in the world is just over a mile deep. The deepest hole (just a borehole) is 7.6 miles deep. The NIF facility itself is in a building at ground level. All of this information is trivially avaible to you at http://www.google.com or http://en.wikipedia.com.

20 miles is a nonsensical statement, a simple demonstration of your lack of facts.

It was a joke kelseymh and whatsisface.

Good point, 20 miles could easily be into the upper mantle :-P

I wonder how soon it will be before we can time travel, and teleport, and all teh other fictional stuff.

Time travel may or may not violate general relativity; the jury is still out on that one. However, if it doesn't you still need a material with a negative energy density (technically, "violates the weak average energy condition") to hold open the wormhole. Same goes for teleporting.

What other fictional stuff do you want? We already have wristwatch computers, talking robots, travel to other planets. What I want is my flying car! It's the 21st Century, dammit! Where's my flying car?!?

I have a magazine about it - along with your comment... :-)

P1010001.JPG

Hah! Most excellent :-) P.S. You have excellent taste in laptops (my iBook G4's motherboard died back in September; I now have a 13" MacBook).

Probably not so excellent now... :-)

I needed a more powerful computer, so I have recently won a faulty G5 from ebay for £140 and my dad and I are going to try fix it...

If I can get it working, it will save me maybe about a £1000.

But I still fine laptops very handy!

(Oh, sorry for the yellow quality image, my camera is not very good...)

P1010001.JPG

LOL,But there is already a flying car.

Ya but it is not fit for commercial use. Remember they said we would also have robot assistants by the 50's and were still waiting.

You can make your own, the technology is there.

What are the specks for the robot and also its capabilities.

I already has a time machine, Its disguised as a carboard box It has one speed I get in and wait 2 minutes, for the machine to warm up and magically i come out 2 minutes in the future I would show you, but my mom recycled it >:[|

Haha, too bad, do you think you can make another one?

idk... cardboard boxes are hard to come by these days

Same goes for teleporting.

The "type" used in Star Trek shows, uses much MUCH too much energy (I remember reading somewhere that there wasn't enough energy in the known universe to break down one human and teleport him to the surface of a planet from a sustained orbit.

i have a time machine that i am willing to sell you. you go in for 60 minutes and come out 1 hour in the future.

you did? sorry, the comment list is so long that i didn't read it.

lol, its just a box you wait in with fancy fake controls....

for the low price of only $ 19.99 ...

then really fast speel of all the other costs....lol

I have to go with Mr. Hawking on this one, as he feels it is not possible for anything larger then a quark.

Hawking just wants decent healthcare!

You saw that he left Cambridge for a Chair at the Perimeter Institute in Ontario?

No, it wasn't my turn to keep track of him this past year ;-)

My wife had a great observation about 10 years ago. Hawking did (does?) a quarter sabbatical every year at Caltech, when I was a grad student there. He was giving a seminar, so I asked my wife if she'd be interested in attending.

When we were there, she noticed that the auditorium wasn't accessible. Hawking had to come in through a freight entrance in the back in order to get to the stage. And he was at Caltech every year. Sigh...