# The Naked Scientists Forum

### Author Topic: What happens to anti-matter as it approaches the speed of light?  (Read 1787 times)

#### puppypower

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##### What happens to anti-matter as it approaches the speed of light?
« on: 25/09/2015 13:37:33 »
If matter is given velocity and begins the approach the speed of light, relativistic mass increases, time slows and distances contract; special relativity. Since anti-matter is the opposite of matter, does the opposite happen?

#### Colin2B

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##### Re: What happens to anti-matter as it approaches the speed of light?
« Reply #1 on: 25/09/2015 14:50:06 »
No, antimatter is not the opposite of matter in every respect, only in certain properties.

#### PmbPhy

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##### Re: What happens to anti-matter as it approaches the speed of light?
« Reply #2 on: 25/09/2015 15:00:52 »
Quote from: puppypower
If matter is given velocity and begins the approach the speed of light, relativistic mass increases, time slows and distances contract; special relativity. Since anti-matter is the opposite of matter, does the opposite happen?
I'm afraid that you have the wrong idea of what antimatter is. Every elementary subatomic particle has a particle which has the same mass but opposite charge,  lepton and baryon numbers and quantum spin. Which particle is antimatter is simply a matter of convention. For example: the anti-particle to the electron is the positron aka antielectron. But there's no reason why the positron couldn't be the particle and its antiparticle, the electron, would then be called the antipositron.

#### lightarrow

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##### Re: What happens to anti-matter as it approaches the speed of light?
« Reply #3 on: 25/09/2015 18:39:00 »
If matter is given velocity and begins the approach the speed of light, relativistic mass increases,
Correct.
Quote
time slows and distances contract; special relativity.

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lightarrow

#### PmbPhy

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##### Re: What happens to anti-matter as it approaches the speed of light?
« Reply #4 on: 25/09/2015 22:30:01 »
Quote from: lightarrow

Quote from: puppypower
time slows and distances contract; special relativity.
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lightarrow
You're wrong on that part my friend. Please tell me why you think that it's incorrect and why popular books are wrong. See the derivation I wrote for rods which are parallel to the x-axis and when the rod is not parallel to the axis at:

http://home.comcast.net/~peter.m.brown/sr/lorentz_contraction.htm
http://home.comcast.net/~peter.m.brown/sr/lorentz_contraction_2.htm

This is simply Lorentz contraction and find it hard to believe that you don't accept special relativity. In my experience with you I always recall that you've always been
You recall length contraction from special relativity don't you? So long as he's talking about distances parallel to lengths parallel to the direction of the axis which is parallel to the direction that he's moving parallel to then he's to then he's correct to then he's correct to then he's right. See https://en.wikipedia.org/wiki/Length_contraction
« Last Edit: 25/09/2015 23:28:04 by PmbPhy »

#### lightarrow

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##### Re: What happens to anti-matter as it approaches the speed of light?
« Reply #5 on: 26/09/2015 01:11:16 »
Quote from: lightarrow

Quote from: puppypower
time slows and distances contract; special relativity.
You're wrong on that part my friend. Please tell me why you think that it's incorrect and why popular books are wrong.
1) "Time slows" is incorrect because "time" flows always with the same speed. What changes is the time interval between two events, if measured in two different frames of reference. It's very different from saying "time slows". If time slowed going fast, then both an astronaut and a man on Earth should experience the same slowing of time, since both goes fast with respect to the other...
2) "Distances contract". Written this way seems that objects are compressed as if they were pressed when they go fast, but it's not: the spaceship is not demolished by its velocity. And the same objections of 1) is valid: if the spaceship is contracted with respect to Earth, then the Earth is contracted with respect to the spaceship. Which of the two is really contracted? We still have to compare distance between two different events, in two different frames of reference, otherwise the OP statements are totally meaningless.

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lightarrow

#### PmbPhy

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##### Re: What happens to anti-matter as it approaches the speed of light?
« Reply #6 on: 26/09/2015 02:41:08 »
Quote from: lightarrow
1) "Time slows" is incorrect because "time" flows always with the same speed. What changes is the time interval between two events, if measured in two different frames of reference. It's very different from saying "time slows". If time slowed going fast, then both an astronaut and a man on Earth should experience the same slowing of time, since both goes fast with respect to the other...
2) "Distances contract". Written this way seems that objects are compressed as if they were pressed when they go fast, but it's not: the spaceship is not demolished by its velocity. And the same objections of 1) is valid: if the spaceship is contracted with respect to Earth, then the Earth is contracted with respect to the spaceship. Which of the two is really contracted? We still have to compare distance between two different events, in two different frames of reference, otherwise the OP statements are totally meaningless.
When someone is speaking of time dilation or length contraction and they don't explicitly mention the frame of reference it happens relative to then its always assumed, just like we assume there is a frame of reference implicit in a conversation in which we're talking about velocity. Merely saying that distance doesn't contract is very misleading.

#### lightarrow

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##### Re: What happens to anti-matter as it approaches the speed of light?
« Reply #7 on: 26/09/2015 07:46:52 »
Quote from: lightarrow
1) "Time slows" is incorrect because "time" flows always with the same speed. What changes is the time interval between two events, if measured in two different frames of reference. It's very different from saying "time slows". If time slowed going fast, then both an astronaut and a man on Earth should experience the same slowing of time, since both goes fast with respect to the other...
2) "Distances contract". Written this way seems that objects are compressed as if they were pressed when they go fast, but it's not: the spaceship is not demolished by its velocity. And the same objections of 1) is valid: if the spaceship is contracted with respect to Earth, then the Earth is contracted with respect to the spaceship. Which of the two is really contracted? We still have to compare distance between two different events, in two different frames of reference, otherwise the OP statements are totally meaningless.
When someone is speaking of time dilation or length contraction and they don't explicitly mention the frame of reference it happens relative to then its always assumed, just like we assume there is a frame of reference implicit in a conversation in which we're talking about velocity. Merely saying that distance doesn't contract is very misleading.
Not only the frame of reference must be specified, but also the fact we are talking of a couple of *events*, as I wrote.
Not specifying all these things is as misleading as writing "hot water freezes faster than cold water" without specifying that some hot water vaporizes when you put it in the fridge, or that a body's energy is m*c2 without specifying that this is only true when the object is stationary, etc.

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lightarrow

#### The Naked Scientists Forum

##### Re: What happens to anti-matter as it approaches the speed of light?
« Reply #7 on: 26/09/2015 07:46:52 »