Physicists Turn Pull Into Push

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Physicists Turn Pull Into Push

Posted by samzenpus on Monday December 10, 2012 @10:45AM 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."

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Repulsion Engines Online by lawnboy5-O · 2012-12-10 10:45 · Score: 3, Interesting

Make it so!
1. Re:Repulsion Engines Online by earls · 2012-12-10 11:22 · Score: 1
  
  Amen. Antigravity, finally.
2. Re:Repulsion Engines Online by Tough+Love · 2012-12-10 11:28 · Score: 4, 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.
  
  --
  When all you have is a hammer, every problem starts to look like a thumb.
3. Re:Repulsion Engines Online by able1234au · 2012-12-10 11:50 · Score: 1
  
  Where's my tractor beam?
4. Re:Repulsion Engines Online by Anonymous Coward · 2012-12-10 13:29 · Score: 0
  
  He wanted a hoverboard instead, helluva lot more convenient.
5. Re:Repulsion Engines Online by tepples · 2012-12-10 13:42 · Score: 1
  
  He wanted a hoverboard instead, helluva lot more convenient.
  Not over water, it isn't, unless you've got power.
6. Re:Repulsion Engines Online by Anonymous Coward · 2012-12-10 15:13 · Score: 0
  
  POOWWWAAAA
  Bleh
7. Re:Repulsion Engines Online by Anonymous Coward · 2012-12-11 07:48 · Score: 0
  
  Probably somewhere near your tractor (hiding)
They could have just asked any geek by Anonymous Coward · 2012-12-10 10:47 · Score: 2, Funny

They seem to have that repulsion charge with girls.
1. Re:They could have just asked any geek by Anonymous Coward · 2012-12-10 10:52 · Score: 5, Funny
  
  So you are saying that if a geek guy stops and listens to a girl, that she'll find him attractive?
2. Re:They could have just asked any geek by MightyYar · 2012-12-10 11:01 · Score: 1
  
  That wears off around 30 or so...
  
  --
  W..w..W - Willy Waterloo washes Warren Wiggins who is washing Waldo Woo.
3. Re:They could have just asked any geek by OneAhead · 2012-12-10 11:15 · Score: 1
  
  Well played sir or madam. Very well played.
4. Re:They could have just asked any geek by Anonymous Coward · 2012-12-10 11:19 · Score: 0
  
  That wears off around 30 or so...
  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. Eventually they figure out that emotionally or physically abusive "bad boys" were a bad choice and that no good man will want them unless they get their values straightened out.
  
  Course lots of women never figure that out. They wind up bitter and angry, with the attention span of a two-year-old, soon as the beauty fades. You can usually find those wherever there are waitstaff, impatiently demanding a lot more assistance than they really need, complaining all the while, hoping and praying the server will lose his cool and give them something to bitch to management about, for this type of person loves to abuse a captive audience.
5. Re:They could have just asked any geek by somersault · 2012-12-10 11:21 · Score: 2
  
  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.
  
  --
  which is totally what she said
6. Re:They could have just asked any geek by somersault · 2012-12-10 11:25 · 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.
  
  --
  which is totally what she said
7. Re:They could have just asked any geek by Nerdfest · 2012-12-10 11:51 · Score: 3, Insightful
  
  A more jaded person would say it wears off around $100K or so.
8. Re:They could have just asked any geek by besalope · 2012-12-10 12:25 · Score: 3, 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?
9. Re:They could have just asked any geek by I+Mean,+What · 2012-12-10 12:26 · Score: 3, Funny
  
  Wait, who's bitter and angry?
10. Re:They could have just asked any geek by somersault · 2012-12-10 22:25 · Score: 2
  
  Only one of them was into that type of thing, so we'll never know.
  
  --
  which is totally what she said
11. Re:They could have just asked any geek by Anonymous Coward · 2012-12-11 08:26 · Score: 0
  
  It's actually above average(in terms of intelligence) females who understand this. However many of them are what most males would consider average in terms of looks but meh, when you have a partner who is also your friend, looks can come a bit down the list, but only a bit. A poor personality can degrade a hot woman's appeal quite a bit.
  The rest I agree with as my partner has seen some of her friends follow that track (ie hot chick gets all attention, plays around, acts the tease, personality is stunted, ends up as either a hooker or doing pr0n etc etc). Seen it happen from the other side as I've made freinds with a few bad-boy cast-offs.
  So altho someone below me got modded funny, that really is how it goes for some people, but hey, I got mine and that's just their tough luck, regardless of gender =D
Other applications by Anonymous Coward · 2012-12-10 10:50 · 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...
1. Re:Other applications by Anonymous Coward · 2012-12-10 11:22 · Score: 1
  
  If you ever need to repel very specifically shaped/timed and energy pulses of charged particles, it would be perfect for a space craft if you don't mind other charged particles still being attracted and it doing nothing for neutral objects.
Great explanations by jez9999 · 2012-12-10 10:51 · Score: 4, 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.

--
== Jez ==
Do you miss Firefox? Try Pale Moon.
1. Re:Great explanations by Anonymous Coward · 2012-12-10 11:38 · Score: 0
  
  its all about the shape and velocity, then. No surprise if small , fast ejaculators repel women
2. Re:Great explanations by Impy+the+Impiuos+Imp · 2012-12-10 12:03 · Score: 2
  
  Even quoting to her how Tony Stark's repulsor rays work?
  
  --
  (-1: Post disagrees with my already-settled worldview) is not a valid mod option.
ION engines? by colin_faber · 2012-12-10 10:53 · Score: 0

This sounds very similar to the idea behind ion engines. It's interesting and I wonder if this discovery was something new, or something finally explained.
1. Re:ION engines? by Anonymous Coward · 2012-12-10 11:03 · Score: 4, Informative
  
  It isn't like an ion engine at all. What they are saying is that electrostatic induction 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.
2. Re:ION engines? by Anonymous Coward · 2012-12-10 11:13 · 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.
3. Re:ION engines? by Anonymous Coward · 2012-12-10 11:54 · Score: 0
  
  > What they are saying is that electrostatic induction
  No, there's no "electrostatic" about it. It's moving charges. Holly crap, moving charges interact with one another! Well yeah...
For the door that you push instead of pull by Anonymous Coward · 2012-12-10 10:53 · Score: 1

Now you won't look so bad.
They should work on the reverse by Spy+Handler · 2012-12-10 11:00 · Score: 2

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.
1. Re:They should work on the reverse by multiben · 2012-12-10 11:15 · Score: 4, Funny
  
  Sure we do. Rope!
2. Re:They should work on the reverse by Anonymous Coward · 2012-12-10 11:29 · Score: 0
  
  So we need to invent an engine that moves the universe backwards.
3. Re:They should work on the reverse by Tough+Love · 2012-12-10 11:33 · Score: 5, Funny
  
  Why didn't I think of that? A matter beam. Brilliant.
  
  --
  When all you have is a hammer, every problem starts to look like a thumb.
4. Re:They should work on the reverse by Carewolf · 2012-12-10 12:04 · Score: 4, Funny
  
  All personal at battle stations: Fire the matter beam!!
  *poke*
5. Re:They should work on the reverse by Anonymous Coward · 2012-12-10 13:24 · Score: 0
  
  New York City!
  Get a Matter Beam!
6. Re:They should work on the reverse by Anonymous Coward · 2012-12-11 01:37 · Score: 0
  
  We have magnets, just no way to pull matter in general.
7. Re:They should work on the reverse by jeffb+(2.718) · 2012-12-11 06:35 · Score: 1
  
  This is my new favorite euphemism of the day.
This is not news by G3ckoG33k · 2012-12-10 11:30 · Score: 1

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?
1. Re:This is not news by Tablizer · 2012-12-10 11:48 · Score: 1
  
  And it had nothing to do with those 8 beers you had?
  
  --
  Table-ized A.I.
Brazilians did too by Anonymous Coward · 2012-12-10 11:31 · Score: 0

Tell a brasilario to push something and see what happens
Re: by Anonymous Coward · 2012-12-10 11:50 · Score: 0

Did it spread into the right shape and move fast enough?
theoretical bs by illestov · 2012-12-10 12:10 · Score: 1

sigh.. another ridiculous claim from some random physicist grabs the headlines because it "violates the laws of physics"

And if a charge moves through the glass faster than light can, it creates a shockwave of light
1. Re:theoretical bs by Chuckstar · 2012-12-10 12:20 · Score: 4, 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.
2. Re:theoretical bs by History's+Coming+To · 2012-12-10 12:29 · Score: 4, Informative
  
  Nope, they're referring to Cerenkov radiation, it's a known effect and produces a very pretty blue light in nuclear reactors. It occurs when the phase velocity travels faster than the speed of light in that medium which is all fine and dandy and breaks no rules at all.
  
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  Please consider this account deleted, I just can't be bothered with the spam anymore.
3. Re:theoretical bs by illestov · 2012-12-10 12:45 · Score: 1
  
  For Cherenkov Radioation , doesn't the charged particle have to move through a dialectic medium, not above its surface?
4. Re:theoretical bs by Anonymous Coward · 2012-12-10 15:03 · Score: 1
  
  Yes, but in this case the particles moving in the glass are being forced by the passing electron outside it.
5. Re:theoretical bs by Anonymous Coward · 2012-12-11 04:44 · Score: 0
  
  A very pretty blue light indeed, that if you find yourself directly observing and appreciating its prettiness it probably also means radiation poisoning of some serious kind
6. Re:theoretical bs by Muad'Dave · 2012-12-11 05:29 · Score: 2
  
  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.
  
  --
  Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
7. Re:theoretical bs by Muad'Dave · 2012-12-11 05:39 · Score: 2
  
  Not in the least. I've been in the 'core' of a couple of small research-grade swimming pool reactors (including this one), and you can see the blue light quite well and with no danger from radiation.
  
  --
  Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
Mr Checkov Deflectors on full! by Anonymous Coward · 2012-12-10 13:24 · Score: 0

Mr Checkov Deflectors on full!
1. Re:Mr Checkov Deflectors on full! by Anonymous Coward · 2012-12-11 13:27 · Score: 0
  
  Mr. Checkov alright. He's right here http://science.slashdot.org/comments.pl?sid=3307513&cid=42247625 saying "it was inwented in Russia" since it's named after Russian scientist Pavel Alekseyevich Cherenkov
pull/push by Anonymous Coward · 2012-12-11 00:48 · Score: 0

I bet they got the idea from Phoebe Buffay:
http://www.youtube.com/watch?feature=player_detailpage&v=pr4UkL-TcHk#t=61s
It's obvious when you think about it by beer_maker · 2012-12-11 05:11 · Score: 1

I was a starship trooper till I took a matter beam to the knee ...

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All you need to do is... by jeffb+(2.718) · 2012-12-11 06:41 · Score: 1

...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.
1. Re:All you need to do is... by Anonymous Coward · 2012-12-11 11:10 · Score: 0
  
  Tsk! It's not 80% of c - I think you'll find it's 88mph that you're thinking of... There was a very clear documentary on this subject just a few years ago.
"Ladies & Gentlemen - What if I told you... by Anonymous Coward · 2012-12-11 13:32 · Score: 0

... That in just a few short years, Your automobile won't even have to touch the ground, at all! With Stark Rubidic Reversion Technology? You'll be able to do, just that..." - Howard Stark, Captain America