Physicists Turn Pull Into Push 60
Posted
by
samzenpus
from the push-me-pull-you dept.
from the push-me-pull-you dept.
sciencehabit writes "It's textbook physics: An electric charge near the surface of a material gets pulled toward the surface. However, if the charge is spread out into the right shape and moves fast enough, that attraction becomes a repulsion, one physicist calculates. The odd finding could help physicists avoid unexpected effects when guiding beams of particles such as electrons."
Repulsion Engines Online (Score:3, Interesting)
Re: (Score:2)
Amen. Antigravity, finally.
Re:Repulsion Engines Online (Score:5, Insightful)
If it works, it's antigravity just as much as a table leg is. In that sense, we have already had antigravity for some time. What you really meant to say is: land speeder, finally.
Re: (Score:2)
He wanted a hoverboard instead, helluva lot more convenient.
Not over water, it isn't, unless you've got power [youtube.com].
Re: (Score:2)
Where's my tractor beam?
They could have just asked any geek (Score:2, Funny)
They seem to have that repulsion charge with girls.
Re:They could have just asked any geek (Score:5, Funny)
So you are saying that if a geek guy stops and listens to a girl, that she'll find him attractive?
Re: (Score:2)
Re: (Score:3)
I have data points that indicate this to be correct at least some of the time. There may be just a little more to it of course, but I'm sure future physics papers will give us some more hints.
Re:They could have just asked any geek (Score:4, Funny)
I have data points that indicate this to be correct at least some of the time. There may be just a little more to it of course, but I'm sure future physics papers will give us some more hints.
Pretty sure those are just outliers. Are you sure p from your dataset is remotely close to 0.05?
Re: (Score:3)
Only one of them was into that type of thing, so we'll never know.
Re: (Score:2)
That wears off around 30 or so...
Re:They could have just asked any geek (Score:5, Insightful)
Yeah that is about when the average female starts to think a solid mate who will provide for her and care about her, is a tad more important than playing idiotic mindgames, teasing, and whoring for attention
Counter-point: it's also when your average geek has settled into a well paying job/career.
Re: (Score:3, Funny)
Re:They could have just asked any geek (Score:4, Insightful)
A more jaded person would say it wears off around $100K or so.
Other applications (Score:1)
How long till we can turn this technology into space ship energy shields? I'm sure they'd be handy with all the space junk we've created...
Re: (Score:1)
Great explanations (Score:5, Funny)
It's textbook physics: An electric charge near the surface of a material gets pulled toward the surface. However, if the charge is spread out into the right shape and moves fast enough, that attraction becomes a repulsion, one physicist calculates.
This finally explains so much about women's behaviour towards me.
Re: (Score:2)
Even quoting to her how Tony Stark's repulsor rays work?
Re:ION engines? (Score:4, Informative)
It isn't like an ion engine at all. What they are saying is that electrostatic induction [wikipedia.org] is not always attractive but it takes very specific conditions to make it repulsive. An ion engine doesn't use induction. Induction is the force between a neutrally charged object and a charged object.
Re: (Score:1)
Ion drives require no such trickery; positive ions are accelerated by the electrical field between a positive and negative grid with enough energy to carry them clear of the negative grid once they've passed through it. There's no attraction turning into repulsion or vice versa, just the basic physics that you learnt at school.
For the door that you push instead of pull (Score:1)
Now you won't look so bad.
They should work on the reverse (Score:3)
we already know lots of ways to push things... jet engines to push planes, gunpowder to push bullets out of a gun, etc.
What we need is a way to PULL things, so we can make a tractor beam. So far we got... nothing.
Re:They should work on the reverse (Score:5, Funny)
Re:They should work on the reverse (Score:5, Funny)
Why didn't I think of that? A matter beam. Brilliant.
Re:They should work on the reverse (Score:5, Funny)
All personal at battle stations: Fire the matter beam!!
*poke*
It's obvious when you think about it (Score:2)
Re: (Score:2)
This is my new favorite euphemism of the day.
This is not news (Score:2)
I woke up one morning and the attraction I had felt the night before had turned into repulsion.
So what is new? That it is on Slashdot?
Re: (Score:1)
And it had nothing to do with those 8 beers you had?
theoretical bs (Score:1)
And if a charge moves through the glass faster than light can, it creates a shockwave of light
Re:theoretical bs (Score:5, Informative)
Nothing in the article violates the laws of physics. It's merely a question of who did the math more accurately for the specific case of the given arrangement of electrons.
Cherenkov radiation is a well understood phenomenon. What you are missing is that the cosmic speed limit is the speed of light in a vacuum. Where the speed of light is slower (i.e. glass), it does not violate the laws of physics for a particle to move faster than that speed. In the given example: the electrons move faster in glass than light moves in glass, but still slower than light moves in a vacuum.
Re: (Score:1)
Re: (Score:1)
Yes, but in this case the particles moving in the glass are being forced by the passing electron outside it.
Re: (Score:3)
For Cherenkov Radioation , doesn't the charged particle have to move through a dialectic medium, not above its surface?
I don't think the charges use spirit guides to exchange logical arguments to resolve disagreements [wikipedia.org].
Re:theoretical bs (Score:5, Informative)
Re: (Score:3)
Not in the least. I've been in the 'core' of a couple of small research-grade swimming pool [wikipedia.org] reactors (including this one [uvamagazine.org]), and you can see the blue light [google.com] quite well and with no danger from radiation.
All you need to do is... (Score:2)
...keep your velocity higher than 80% or so of c. If your velocity drops below the velocity of light in the repelling surface, the Cherenkov radiation goes away, there's no more repulsion, and you land on the surface cruising at .5c or so. Hope the tires on your landing gear are properly inflated.
Actually, now that I think about it, you'd probably get plenty of backup lift from the relativistic plasma formerly constituting the repulsive surface and the bottom of your vehicle. I withdraw my objection.