Large Hardon Collider

[Pirian]

New episode of The Universe on history channel right now, great stuff

[Eliseos]

Oh wow, you're absolutely right. My professor even did this in class to simplify Planck's equation, and in my early morning drone student state I completely forgot about it, even though it's in my notes lol. Thanks for the tip.

Also, just look it up on wikipedia, lol Wien's displacement law - Wikipedia, the free encyclopedia

[Kaylia]

http://img7.imageshack.us/img7/76/radial.jpg



Got a last question about this. What kind of formalism should I use to change the d/dr to d/dz in the equation above. d/dr is an operator, and changing the denomitor for a*dz feel completely wrong. I know it works because it's a linear operator, but I'm curious to see how a mathemacian would write it.

[edit]
Everything is printed and done now. Althought, I would still like to know how you demonstrate that d/dr = (1/a)*(d/dz) formally.

[Woozie]

I've been overwhelmed with homework lately, but I'll look over your problem to see what you're doing and explain it from a mathematicians perspective within the next few days.

I'll check yours out too, Eliseos.

Also, for my equations, I use

Online LaTeX Equation Editor

If you've never used LaTex, typing it out there would probably take forever. But if you're used to LaTex, it's pretty fast and convenient. The only problem is that if someone is viewing the forums on a dark skin (like BlackSmart), the equations look like garbage.

How are you making yours, Kaylia?

[Kaylia]

Don't worry about it if you're short on time, I'm almost certain it's justified with linear operator...I just wanted to use the correct formalism, since half of the class are rabid mathematicians who stare at you weirdly when you take physicist shortcut.


I used microsoft equation editor integrated in word (Mathtype) for this.

I'm trying to get into latex this semester, but since I'm working on short deadline atm, I didn't want to spend 5 hours writting radial equation, and went for the user friendly crap. I do prefer latex formating, but it's not a luxury I can afford at the moment, since the presentation is tomorrow at 12pm, and I have 40-50 equations to write.

It's a pretty nice link you gave me here.I will definitively use it in the future.

[Chun Liroy]

I never read anything in this thread.
http://lonebannana.com/blog/wp-conte...free-will1.png

[Eliseos]

Grats.

[Max™]

http://i341.photobucket.com/albums/o...imethreads.jpg

What I have so far.

[oldoldman]

Thought you guys would enjoy this.

http://imgs.xkcd.com/comics/right_hand_rule.png

[zoobernut]

Lol I like the last one.

Also very cool news about ion rocket drives. Short article not much information but it does say they are going to start testing the ion rocket engines in 2013 in space.

Ion Rocket Engine Can Take Us to Mars Faster - Tom's Guide

The mission to Mars is something that's finally closer to reach, thanks to an ion propulsion system designed partly in Canada. Yes, it's kind of like Star Trek and ion propulsion should in theory allow us to travel in space faster than ever.

In fact, the new rocket engine design could allow astronauts to travel to Mars in just 39 days – a monumental discovery, considering conventional rockets would require six months for the same journey.

This is particularly important because Mars and Earth only pass close together once every two years, meaning that astronauts would have to travel to and from only during those periods. Such a wait time would require a surplus of supplies of food, air and water.

With ion propulsion's expected 39 day trip time, astronauts would be able to make a return trip during the same Earth/Mars pass.

"If you can cut that voyage down to just a matter of seven or eight weeks then of course you can carry way less stuff," Canadian astronaut Chris Hadfield said Tuesday on Canada AM. "And if you don't have to carry so much fuel to slow down when you get there or to bring you back, it just scopes the whole thing down to where it becomes maybe a practical problem to solve rather than an almost an impossibility."

The ion drive engine is able to turn electrical power into thrust, which would make solar panels extra useful. And how might these engines be used?

"The big difference is you don't just fire your engines for 10 minutes and then coast for six months. You can continue to thrust the whole way," Hadfield said. "And what you do is thrust for 16 days or 18 days going one way and then you turn around backwards and you slow down. So you keep your engine running the whole way."

The tests for this engine are expected to commence around 2013 on the International Space Station
.

The coolest part is that theoretically it could cut a trip to mars down to 39 days.

[Mizango]

Yeah, Ion engines are interesting. I heard it brought up right after I got out of college during a lecture by Physicist Ed Groth. The advantages to something like that or some sort of ion propulsion would be awesome.

[Max™]

Give me time and I will make you wings of cosmic string to swim through spacetime at relativistic velocities.

Surprises from General Relativity: "Swimming" in Spacetime: Scientific American

Yosi (Joseph) Avron Site


A defect in spacetime in my model would be a line of threads out of place, a loop of threads around others, a plane cutting across others, or a hole, ranging from a monopole point defect (all but impossible), to an event horizon.


Think about a circular sheet of cellophane sandwiched between two densely bristled brushes.

Now imagine the sheet changing shape from a circle, flowing to one side into a triangular shape, thinning out and stretching further that way, then resuming a more circular shape.

http://i341.photobucket.com/albums/o...paceflight.jpg

It would begin to move across the bristles.

Do that with spacetime defects, it would begin to move across the threads, and you would get motion without tossing anything out behind your craft.

[zoobernut]

I heard about the ion drive systems a long time ago too but they were theoretical then and just barely getting to the point where they were building them. I am amazed that we are this close to actually testing an ion engine in space. Can you imagine? A 39 day trip to Mars makes it actually plausible to put man on Mars.

Also Max that is a very interesting concept it really does seem like swimming through spacetime. We could build a giant ship in the shape of a manta ray then.

[Kaylia]

I didnt know ion engine were that close from completition...hell, I didnt even know they were working on that.


About the swimming thing, good luck...Quickly changing your shape around a manifold sound like something that would require a lot more energy in the end compared to conventional method.



[edit]
Fuuuuuuuuuu...

I just spent the last 20min trying to understand why d/dx ( sin(x)^-1) was giving me csc*cot, when derivative table were giving me 1/sqrt(1-x) for sin^-1(x)....
That has to be the dumbest thing i've done recently.

[Kryssan]

I think it's great they're advancing with Ion Engines, but you realize this is not the first craft to use them, right? Not by a long shot. NASA already deployed a probe using an IPS drive on October 24, 1998. This one mentioned in the article would just be much larger and/or capable of more thrust than that one was.



If you don't know what I'm talking about... sad day.

[Max™]

About the swimming thing, good luck...Quickly changing your shape around a manifold sound like something that would require a lot more energy in the end compared to conventional method.



[edit]
Fuuuuuuuuuu...

I just spent the last 20min trying to understand why d/dx ( sin(x)^-1) was giving me csc*cot, when derivatible table were giving me 1/sqrt(1-x) for sin^-1(x)....
That has to be the dumbest thing i've done recently.

Hah, even I see what you did there, tossing your parentheses around carelessly.

The swimming thing would just require actively controlling a domain wall defect, which would require technology I can't even begin to describe properly, so I'll just say it would take magic.

it should be possible though.


The ion drive is just impressive because it is soooooooooo much stronger than the ones used for the '98 mission, which was about as much push as a sheet of paper laying on your hand.

[Kaylia]

I'm not talking about the wall defect, I was talking about the link you posted, unless it was the same, because it felt kinda different.

[Max™]

Oh, that link was the same idea but much MUCH less effective.

It's still more efficient over a long term than throwing out reaction mass, particularly in a highly curved region of spacetime.

[Khamsin]

I think it's great they're advancing with Ion Engines, and I'm gonna let you finish, but the NASA probe deployed on October 24, 1998 used the best IPS drive of all time.

.

[Kryssan]

The ion drive is just impressive because it is soooooooooo much stronger than the ones used for the '98 mission, which was about as much push as a sheet of paper laying on your hand.

Not arguing that, just that people seem to be of the opinion that it was something that remained theoretical instead of something we've already had experience using. Any application of an ion drive for transporting people and/or supplies would definitely need to produce more than 19~92mN of thrust ~ assuming you want to get there in a reasonably quick fashion, that is.

.

I would say I see what you did there Khamsin, but I guess I don't see the point in it.