Beta

Slashdot: News for Nerds

×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

LHCb Experiment Observes New Matter-Antimatter Difference

Unknown Lamer posted about a year ago | from the anti-matter-was-fired-years-ago dept.

Science 129

An anonymous reader writes "Matter and antimatter are thought to have existed in equal amounts at the beginning of the Universe, but today the Universe appears to be composed essentially of matter. By studying subtle differences in the behavior of particles and antiparticles, experiments at the LHC are seeking to cast light on this dominance of matter over antimatter. Now the LHCb experiment has observed a preference for matter over antimatter known as CP-violation in the decay of neutral B0s particles. The results are based on the analysis of data collected by the experiment in 2011."

cancel ×

129 comments

IT IS JUST A GAME !! (-1)

Anonymous Coward | about a year ago | (#43535825)

Wizards of a modern age
Cast spells of electric power
But the corporate string that make them dance
Lead up to an ivory tower
There sits the fates in solitude
Far from the public eye
No one ever sees them smile
And nothing makes them cry

Welcome to the kingdom,
The land of bought and sold
A world of real-life fantasy
Where truths are seldom told
Try hard to remember
All that glitter is not gold
You can pay the piper
But you cannot buy his soul

It's just a game, you're in it all the way
It's just a game, don't let yourself slip away
It's such a shame, I heard somebody say
It's just a game and all I can do - Is play !!

What do you choose now, what do you believe now?
Who are you going to trust?
All your dreams and fancy schemes just crumble into dust
Calm and cool and computerized
They RPN calculate and collect
We wait and watch and wonder
Just which puppet they'll select

Like the moth too near the flame
Who learned his truth too late
We're all too deep into the game
That is the master our fate

The poets and the pipers have got their motives
And you've got yours, no doubt
And so the game continues
That's what it's about

Re:IT IS JUST A GAME !! (-1)

Anonymous Coward | about a year ago | (#43536149)

You gonna give credit to who you copied that from, fuckass?

The Universe has BO (-1)

Anonymous Coward | about a year ago | (#43535841)

I knew it!

Re:The Universe has BO (0)

Thanus (615133) | about a year ago | (#43536501)

Now we just need Prof. Farnsworth's smell-o-scope!

Re:The Universe has BO (0)

Anonymous Coward | about a year ago | (#43539249)

Now that they have been cancelled again, perhaps he'll sell it to you.

I'm Definitely Antimatter (5, Funny)

Anonymous Coward | about a year ago | (#43535873)

Now the LHCb experiment has observed a preference for matter over antimatter known as CP-violation

If the pro-matter people are violating CP laws, I want nothing to do with them.

Just Say No to matter!

Re:I'm Definitely Antimatter (1, Funny)

game kid (805301) | about a year ago | (#43535951)

You vile soulless lapdog! Those Civil Protection jackboots must be disobeyed as often as possible!

Re:I'm Definitely Antimatter (2, Funny)

Anonymous Coward | about a year ago | (#43535985)

But by preferring antimatter to matter, you're also violating CP laws. Down with matter-ism!

Re:I'm Definitely Antimatter (0)

NatasRevol (731260) | about a year ago | (#43536259)

I'm proud to say I'm a matterist, and I don't care who knows it.

Re:I'm Definitely Antimatter (0)

Anonymous Coward | about a year ago | (#43536407)

I'm proud to say I'm a matterist, and it doesn't matter who knows it.

FTFY

Re:I'm Definitely Antimatter (1, Offtopic)

gomiam (587421) | about a year ago | (#43538275)

I am completely amatteurish, and I don't know which one is better.

Re: I'm Definitely Antimatter (0)

Gilmoure (18428) | about a year ago | (#43536985)

You're saying it just doesn't matter?

Re:I'm Definitely Antimatter (0)

Anonymous Coward | about a year ago | (#43537745)

Violating CP Laws? CP Violations? Sounds like a horror story from a probation or parole officer's desk.

Re:I'm Definitely Antimatter (1, Flamebait)

steelfood (895457) | about a year ago | (#43538575)

We need more restrictive CP laws so that it'll be harder for them to be violated in the future.

Re:I'm Definitely Antimatter (2)

K. S. Kyosuke (729550) | about a year ago | (#43539713)

Just Say No to matter!

I've been saying "no" my whole life and I still don't matter.

other lesser known cosmic (-1, Offtopic)

nimbius (983462) | about a year ago | (#43535907)

truths include its preferences for organic food, bob dylan music, and neil degrasse tyson.

A: Becuase it breaks the flow of a message (5, Informative)

DNS-and-BIND (461968) | about a year ago | (#43535923)

Q: Why is starting a comment in the Subject: line incredibly irritating?

Re:A: Answering a question (1)

Dupple (1016592) | about a year ago | (#43535973)

before it's asked is even worse

Re:A: Answering a question (1)

Zero__Kelvin (151819) | about a year ago | (#43536287)

Nobody asked what was worse!

Re:A: Answering a question (1)

berashith (222128) | about a year ago | (#43539257)

who asked what was worse?

Re:A: Answering a question (2)

Zero__Kelvin (151819) | about a year ago | (#43539457)

Who's on first, and didn't ask what was worse. I Don't Know didn't ask what was worse either.

Re:other lesser known cosmic (0)

Anonymous Coward | about a year ago | (#43535981)

truths include its preferences for organic food, bob dylan music, and neil degrasse tyson.

check more at: urenhud.com

um, of corse they did. (-1)

Anonymous Coward | about a year ago | (#43535921)

I learned this junk on jersey shore.

What if light travels REAL SLOW (0, Funny)

Anonymous Coward | about a year ago | (#43535961)

Imagine if a photon travels not much faster than an electron (a few cms a second) and the effect we observe as light is no different than the thrust we observe from an electron. A push in much smaller particles.

Since we only observe a photon by detecting it indirectly via promotion/demotion of electrons, a photon could be very very very small. And yet we can only detect an aggregate capable of promoting an electron. If it can't promote or demote then it can't be detected and we think it isn't there.

What if matter and anti matter are just different arrangements of much smaller charged particles, any particle you can make that is stable, must also have an anti particle that is stable because you could swap all the -ve for +ve particles.

What if light is really just tiny one +- fundamental particles and not the much larger photon claimed.

What if space is matter and there's no such thing as a vacuum?

Re:What if light travels REAL SLOW (5, Insightful)

wonkey_monkey (2592601) | about a year ago | (#43536137)

What if monkeys can actually talk but refuse to do so because they don't want us to know?

What if quarks are actually microscopic doughnuts, and we can fly through them into an alternate universe where Snooki is president?

What if... ah, screw it, if you can't see where I'm going with this by now there's no hope for you.

Re:What if light travels REAL SLOW (1)

NatasRevol (731260) | about a year ago | (#43536283)

What if space is matter and there's no such thing as a vacuum?/quote

NASA is going to be PISSED!!!

Re:What if light travels REAL SLOW (5, Funny)

Anonymous Coward | about a year ago | (#43536815)

What if space is matter and there's no such thing as a vacuum?/quote

NASA is going to be PISSED!!!

Slashdotter discovers simple $5 trick that makes NASA scientists FURIOUS! Click your age to discover this trick for yourself!
[ <18 ] [ 18 - 24 ] [ 25 - 40 ] [ 41 - 55 ] [ 56 - 70 ] [ 71+ ]

Re:What if light travels REAL SLOW (2)

Artifakt (700173) | about a year ago | (#43537981)

James Dyson is going to be even more pissed. Freeman Dyson probably will be too. Why is the AC trying to piss off all sorts of Dysons?

Re:What if light travels REAL SLOW (4, Funny)

MiniMike (234881) | about a year ago | (#43538223)

James Dyson is going to be even more pissed. Freeman Dyson probably will be too. Why is the AC trying to piss off all sorts of Dysons?

He's probably hoping all the Dysons come to see him at the same time and angrily surround him.

He will then claim that he has the only Dyson sphere made out of real Dysons.

Re:What if light travels REAL SLOW (1)

Ioldanach (88584) | about a year ago | (#43536437)

What if space is matter and there's no such thing as a vacuum?

That's it! All we have to do is dephlogisticate a large quantity of rocket fuel and we'll reach the aether!

Re:What if light travels REAL SLOW (1)

PhilHibbs (4537) | about a year ago | (#43536465)

Imagine if a photon travels not much faster than an electron (a few cms a second)...

Electrons can and often do travel much faster than that, but they go round and round in tiny circles and only drift through a conductor at an aggregate speed of a few cm per second. An electron's actual speed is, as with all physical things, based on its energy. You might as well imagine how fast rocks travel.

Re:What if light travels REAL SLOW (0)

Anonymous Coward | about a year ago | (#43536673)

Nah, they don't actually move, they just have a probability of being somewhere at any given time.

Re:What if light travels REAL SLOW (0)

Anonymous Coward | about a year ago | (#43536519)

Hey, man, you should like, totally, like pass that joint already. You're campin' bro, puff puff GIVE!

equal amounts at the beginning of the Universe (1)

Anonymous Coward | about a year ago | (#43535965)

Matter and antimatter are thought to have existed in equal amounts at the beginning of the Universe

yes, both zero at the beginning.

Re:equal amounts at the beginning of the Universe (0)

Anonymous Coward | about a year ago | (#43536131)

The fun thing about energy is that if you have a "positive" energy and a "negative" energy of equal amounts, then you still have a net energy of zero.

Re:equal amounts at the beginning of the Universe (1, Funny)

UnknownSoldier (67820) | about a year ago | (#43536151)

/sarcasm. Right, the universe just spontaneous came into existence.

From the Laws of Thermal Dynamics we know energy can not be created nor destroyed.
Einstein showed us all Matter is Energy.
Therefore the Universe has ALWAYS existed in one form or another.
Q.E.D.

Re:equal amounts at the beginning of the Universe (5, Insightful)

i kan reed (749298) | about a year ago | (#43536353)

You say "QED" like science is a closed method of understanding like logic is. The scientific method makes acknowledgement that its results are only accurate in as far as the controls we've been able impose in our experimentation and observation hold. We have never tested the laws of thermodynamics in conjunction with a singularity, and thus anything we say about their behavior there is an extrapolation. Extrapolation isn't induction, and what you just said isn't a proof.

Re: equal amounts at the beginning of the Universe (1)

Gilmoure (18428) | about a year ago | (#43537001)

All physical laws breakdown before Big Bang.

Re: equal amounts at the beginning of the Universe (0)

Anonymous Coward | about a year ago | (#43537105)

Logic too.

Re: equal amounts at the beginning of the Universe (1)

i kan reed (749298) | about a year ago | (#43537857)

See, but that's a positive assertion that's actually quite unprovable. We know there are a subset that cannot operate as we define them today because contradictions would arise, but that's not the same as them. There may be underlying rules/laws to the ones we use today that would continue to make sense under those conditions.

I'm not saying there are, but you're the one making a positive assertion.

Re: equal amounts at the beginning of the Universe (4, Insightful)

Electricity Likes Me (1098643) | about a year ago | (#43539219)

This is incorrect. All currently known laws become meaningless as all your variables go towards infinity. This doesn't mean there are no laws - simply that we lack the theory to describe them in such extreme conditions.

It's the "what's infinity * infinity? Infinity!" - it doesn't really describe anything real. Of course, this situation changes dramatically if we could show that the variables didn't go to infinity, but were bounded in some fashion. Presently, we can't though.

Re:equal amounts at the beginning of the Universe (-1)

Anonymous Coward | about a year ago | (#43537327)

Again: why are americans so obsesssed with the word "thermodynamics"?
Thermodynamics is a very very very small part of physics. The rest of the physics workd has absolutely nothing to do with it.
So why the fuck do you want to "test thermodynamics" in conjunction with a similarity?
On top of that: do you know that termo dynamics in fact dont define any physical law? They only describe observations, which are usefull for (calculations regarding) thermal engines, pressure and entropy etc.
Unlike real physics like quantum physics or laws of gravity they are not "laws". And the rest of the world btw. distinguishes between LAWS of physics and "GENERAL PRINCIPLES" ... Thermodynamics is only a general principle.

Re:equal amounts at the beginning of the Universe (1)

i kan reed (749298) | about a year ago | (#43537805)

Hmm, parts of this are accurate and really not contrary to my point, and parts are downright crazy, incorporating some sort of bizarre nationalism, a fundamental misunderstanding of the scientific method, and directionless babble about how wrong I(or was the GP?) am about something non-specific. I have a feeling that if I could parse your underlying point out from that word-salad I'd disagree, but I can't even say that for sure.

Re:equal amounts at the beginning of the Universe (1)

lister king of smeg (2481612) | about a year ago | (#43536483)

/sarcasm. Right, the universe just spontaneous came into existence.

From the Laws of Thermal Dynamics we know energy can not be created nor destroyed.
Einstein showed us all Matter is Energy.
Therefore the Universe has ALWAYS existed in one form or another.
Q.E.D.

you are forgetting zero point energy where a negative and a positive particle spontaniously (for lack of a better word) spawn and then annihilate each other leaving the balance at zero. this does not violate thermodynamics as the balance is maintained. Is it possible that the universe is nothing more than a very large zero point even where the antimatter will eventually annihilator all the matter?

Re:equal amounts at the beginning of the Universe (1)

Anonymous Coward | about a year ago | (#43536801)

That's the problem, there isn't enough anti-matter to annihilate all of the matter. There is a lack of symmetry in the creation of matter and anti-matter.

Re:equal amounts at the beginning of the Universe (2)

camperdave (969942) | about a year ago | (#43538649)

There is a lack of symmetry in the creation of matter and anti-matter.

How do we know this? How do we know that a distant galaxy isn't completely made of antimatter? Does anti-hydrogen fusion in an antimatter star produce a different spectrum than normal hydrogen in a normal matter star?

When the Big Bang happened, both matter and antimatter were created. A goodly amount of it found its opposite and annihilated back to energy. However, the universe was expanding at the time. Eventually the universe would be big enough that a particle and antiparticle could fly away from each other and never meet. There could have been regions where matter predominated, and regions where antimatter did. Maybe the empty spaces between galaxies is where the particle/antiparticle density was roughly the same, and the galaxies are where one type predominated.

Good question! (5, Informative)

Roger W Moore (538166) | about a year ago | (#43539047)

How do we know this?

We know this by looking for gamma rays produced by matter/anti-matter annihilations. The solar wind does not annihilate with out atmosphere so we know the sun is made of matter. This same wind does not annihilate with the interstellar medium in the galaxy so that is made of matter. No other star has visible annihilation lines with this medium either so we can be sure the entire galaxy is made of matter. Further out out galaxy does not create annihilations with the medium in the local super cluster of galaxiesand neither does any other galaxy so we know that the local super cluster is all made of matter.

To go further afield is harder since at this point the distances rule out detecting gamma rays from the incredibly sparse intergalactic medium (at least this was true several years ago - perhaps astronomers can do better now?). So instead what you can do is look at galactic collisions. No colliding pair of galaxies emits gamma radiation consistent with annihilation events so either the universe is really perverse and somehow no pair of colliding galaxies is ever a matter/antimatter pair OR there are no anti-matter galaxies out there to collide with. So while it is impossible to rule out that there might be one or two anti-matter galaxies hiding in some distant corner of the universe there are clearly far, far more matter galaxies than anti-matter ones.

Re:equal amounts at the beginning of the Universe (0)

Anonymous Coward | about a year ago | (#43537245)

Perhaps you should go back to school? There is now law in thermodynamics that shows energy can neither created nor destroyed.

Thermodynamics is about: temperature, hence its name, entropy and pressure.

First Law of Thermodynamics (3, Informative)

Roger W Moore (538166) | about a year ago | (#43539111)

Actually there is [wikipedia.org] . Of course it is only interested in thermal energy but nevertheless it is there. One of the most beautiful bits of mathematics, Nöther's Theorem [wikipedia.org] , shows that for any symmetry there must be a conservation law (or vice versa). For energy the cause of the conservation law is that the laws of physics are all symmetric under translation in time i.e. the laws of physics today are the same as they were yesterday. So while the reason for energy conservation has nothing to do with thermodynamics it is still stated as its first law.

Re:equal amounts at the beginning of the Universe (0)

Anonymous Coward | about a year ago | (#43537397)

Please study some physics that's less than 100 years old.

Re:equal amounts at the beginning of the Universe (0)

Anonymous Coward | about a year ago | (#43537669)

To say the universe 'always' existed is a truism. Without the universe there's no concept of causality and no concept of time. "Always" basically means 'the duration of causality within the universe'. So yeah, sure, the universe 'always' existed. That's true, but irrlevant.

The universe could still have come into existance all on its own. time=0 at some point. For it to do this, it would require a different set of physics than exist within the universe itself. A set of physics where causality didn't apply.

Re:equal amounts at the beginning of the Universe (2)

Culture20 (968837) | about a year ago | (#43537963)

Without the universe there's no concept of causality and no concept of time. ... The universe could still have come into existance all on its own.

Time is the dimension upon which we measure change. Without a dt, dv doesn't happen. Without time, how does the universe change from non-existing to existing?

Re:equal amounts at the beginning of the Universe (2)

Roger W Moore (538166) | about a year ago | (#43539123)

It's not just time: how does anything exist if there is no space?

Re:equal amounts at the beginning of the Universe (-1)

Anonymous Coward | about a year ago | (#43537919)

Oh, I must have missed school on the day that they taught us that all of Einstein's theories were proven to be correct.

Re:equal amounts at the beginning of the Universe (4, Interesting)

buchner.johannes (1139593) | about a year ago | (#43538307)

/sarcasm. Right, the universe just spontaneous came into existence.

From the Laws of Thermal Dynamics we know energy can not be created nor destroyed.
Einstein showed us all Matter is Energy.
Therefore the Universe has ALWAYS existed in one form or another.
Q.E.D.

Indeed, the curvature of the universe corresponds to negative energy, which can make the energy budget zero. See "A universe from nothing" by Lawrence Krauss (talk [youtube.com] here) on why the energy budget can be zero.

One aspect in the big bang is that you can borrow energy from quantum mechanics if you give it back within a short time (the time needs to be shorter the more energy you borrow). Combine this with extremely fast inflation and you can run away with the energy you borrowed.

Re:equal amounts at the beginning of the Universe (0)

Anonymous Coward | about a year ago | (#43536197)

Matter and antimatter are thought to have existed in equal amounts at the beginning of the Universe

yes, both zero at the beginning.

Creation of matter from zero matter is a violation of the second law of thermodynamics.
Not that I say that you are wrong, just that it doesn't seem likely that both are right.

Re:equal amounts at the beginning of the Universe (1)

PhilHibbs (4537) | about a year ago | (#43536369)

The second law of thermodynamics applies within our universe. Who knows what laws governed the creation of that universe in which that law applies? Maybe there's something outside what we naively call "the universe" from which the energy came?

Re:equal amounts at the beginning of the Universe (0)

Anonymous Coward | about a year ago | (#43536663)

He didn't say that conservation of energy was violated (the energy of matter could have come from non-matter particles like photons, Z bosons, gluons, Higgs bosons, and gravitons). He said that the second law of thermodynamics was violated.

Re:equal amounts at the beginning of the Universe (0)

Anonymous Coward | about a year ago | (#43537475)

The second law of thermodynamics is absolutely not relevant for Gedankenexperiments about anti matter and matter. Perhaps you should take the time to actually read it up on wikipedia to get an idea about what it is.

Re:equal amounts at the beginning of the Universe (0)

Anonymous Coward | about a year ago | (#43537809)

Who knows what laws governed the creation of that universe in which that law applies?

God's laws, so God knows.

Re:equal amounts at the beginning of the Universe (5, Interesting)

digitig (1056110) | about a year ago | (#43538345)

Matter and antimatter are thought to have existed in equal amounts at the beginning of the Universe

yes, both zero at the beginning.

Creation of matter from zero matter is a violation of the second law of thermodynamics. Not that I say that you are wrong, just that it doesn't seem likely that both are right.

The simple answer to that is that the second law of thermodynamics is a statistical law, not an absolute one. Entropy in a system can increase with time, but the overall trend is always for entropy to increase. You can see the universe as a temporary statistical blip.

The more accurate answer is to observe that there are issues with the understanding of time itself implied by your observation. On the usual model of the big bang, time itself came into existence at the big bang. Because there was no "before" the big bang, the rate of change of entropy is undefined at the point of the big bang -- it would be the gradient at a singularity, and there's no such thing, so the second law of thermodynamics is meaningless at that point. (And of course even that is a simplification, because phrases like "came into existence" assume time's arrow, which is pretty hotly disputed).

Re:equal amounts at the beginning of the Universe (0)

Anonymous Coward | about a year ago | (#43538937)

Creation of matter from zero matter is a violation of the second law of thermodynamics.

Creation of matter ALONE is a violation of the law of thermodynamics. Creating both a particle and an anti-particle is fine.

Re:equal amounts at the beginning of the Universe (0)

Anonymous Coward | about a year ago | (#43539117)

disregard that; I suck on cocks and physics concepts. -- AC

Re:equal amounts at the beginning of the Universe (1, Interesting)

PhilHibbs (4537) | about a year ago | (#43536289)

My theory is, that matter and antimatter did exist in equal amounts. Matter travels one direction in time, antimatter travels the other direction. So the two forms of matter headed of in different temporal directions, and the original matter and antimatter will never meet. Antimatter can be created in high energy interactions though, which explains why there is some around, but that isn't the original antimatter.

Re:equal amounts at the beginning of the Universe (2, Informative)

Anonymous Coward | about a year ago | (#43536897)

If that were the case, then reactions that produce anti-matter would be detectable before they occur.

Re:equal amounts at the beginning of the Universe (1)

Anonymous Coward | about a year ago | (#43537183)

Why do you think they move in different directions causing them to not meet? There is nothing to support this. Matter and Anti-matter pretty much are the same, other than they cancel out on contact and revert back to energy. There seems to be a bias in the creation of anti-matter, which is strange.

CP (4, Funny)

MagicM (85041) | about a year ago | (#43536081)

"CP-violation"

Right. Like I'm going to click on that link.

I know /. editors love CERN (3, Informative)

Lawrence_Bird (67278) | about a year ago | (#43536097)

but the headline is a bit grandiose - there is nothing new about CP violation. CP violation has been known for a very long time and there are at least three other examples of it prior to LHCb report. Also, as CERN notes, others were not able to accumulate sufficient statistics to make the observational claim. Perhaps "CERN's LHCb confirms CP violation in another particle" my be both a more accurate way of describing it and also less "omg, ponies!"

Re:I know /. editors love CERN (5, Informative)

hajus (990255) | about a year ago | (#43536147)

For the electroweeak force yes, but not in the QCD Lagrangian. B+ meson CP violation is the new part.

Re:I know /. editors love CERN (1)

Anonymous Coward | about a year ago | (#43536315)

this is still the same CKM quark mixing. finding CP violation in the QCD lagrangian would be *really* big news.

Re:I know /. editors love CERN (2)

SleazyRidr (1563649) | about a year ago | (#43539689)

Sometimes I think people are just trolling /. by posting random letters that look like physics, then I spend some time on Wikipedia and realise how little I know.

Re:I know /. editors love CERN (0)

Anonymous Coward | about a year ago | (#43536323)

I got about half of the words. Please repeat, sloooowly.

Really, it's kinda funny reading about physics while realizing my own understanding and knowledge is nowhere near to be able to comprehend wtf has happened, and why it might matter. And i'm not stupid, just never bothered to study physics.

Car Analogy (1)

raftpeople (844215) | about a year ago | (#43536473)

It's normal to find coins under the seat, this time they found coins inside the seat.

Re:I know /. editors love CERN (0)

Anonymous Coward | about a year ago | (#43538277)

Oh, right. Makes perfect sense.

BTW, what language is it?

Re:I know /. editors love CERN (1)

lgw (121541) | about a year ago | (#43538483)

But this was predicted years ago, right? (IIRC there are two commonly predicted CP violations) This is "just" experimental confirmation?

Re:I know /. editors love CERN (2)

mu22le (766735) | about a year ago | (#43536169)

I think the headline is correct, LHCb has observed CP violation in an experimental domain where it had not been observed before. The headline does not claim that LHCb has discovered CP violation.

Re:I know /. editors love CERN (0)

Anonymous Coward | about a year ago | (#43537713)

They observed CP violation in a particle which it had not been observed in before, bringing the total to 4. Since the 1960s. That's new, and worthy of a grandious title if you ask me.

And said title is copied from the CERN press release.

niggers (-1)

Anonymous Coward | about a year ago | (#43536123)

porch monkeys

I'm still not convinced... (1)

phil_aychio (2438214) | about a year ago | (#43536183)

...that we are definitely made of matter. If we were made of anti-matter, wouldn't matter actually look like anti-matter to us, only because it isn't what we're made of? Also, if matter and anti-matter existed in equal amounts at the beginning, wouldn't the remaining particles, regardless of what they are (after all the self-annihilation and whatnot) be considered matter by default?

Re:I'm still not convinced... (2)

ThePeices (635180) | about a year ago | (#43536309)

...that we are definitely made of matter. If we were made of anti-matter, wouldn't matter actually look like anti-matter to us, only because it isn't what we're made of?

Not really. We have defined an electron (matter) as the electron-particle that has a negative electric charge. A positron (anti-electron, antimatter) is an electron with a positive charge. Same goes for protons etc, and we know for certain that we and all the matter around us are composed of the 'matter' version.

Also, if matter and anti-matter existed in equal amounts at the beginning, wouldn't the remaining particles, regardless of what they are (after all the self-annihilation and whatnot) be considered matter by default?

No, because if they were equal in quantity, the left over particles would be a 50-50 mix of matter and antimatter, but this is not the case in reality.

Re:I'm still not convinced... (-1)

Anonymous Coward | about a year ago | (#43536571)

We have defined electron as matter only because it is part of what we're made of. If however, atoms were composed of positrons instead of electrons, wouldn't electrons be considered anti-matter?

Re:I'm still not convinced... (1)

VortexCortex (1117377) | about a year ago | (#43536831)

We have defined electron as matter only because it is part of what we're made of. If however, atoms were composed of positrons instead of electrons, wouldn't electrons be considered anti-matter?

Perhaps, but that's the thing. Super symmetry doesn't exist, so things would work differently in the anti-matter dominated universe.

Re:I'm still not convinced... (1)

Brucelet (1857158) | about a year ago | (#43536949)

Sure, but that's not relevant. We have chosen to label the stuff that dominates our universe as matter because it's what we saw first. Ultimately though it's just a name. We could call them this-matter and that-matter and the physics wouldn't change.

Christopher Walken approves of the parent post. (1)

sconeu (64226) | about a year ago | (#43537843)

We could call them this-matter and that-matter and the physics wouldn't change.

You can go with this or you can go with that [youtube.com]

Re:Christopher Walken approves of the parent post. (0)

Anonymous Coward | about a year ago | (#43538297)

If only more people would Walken-roll instead of Rickroll, the world would be a better place. Bravo!

Re:I'm still not convinced... (0)

Anonymous Coward | about a year ago | (#43537853)

"Matter" is a relative term, based on that which with are most familiar. Anti-matter is whatever is the exact opposite of our "normal" matter. You can't have an "anti" anything without a "normal" something.

How do we know (1)

wisnoskij (1206448) | about a year ago | (#43536667)

What type of matter most of the universe is made of? Past this particular gravity well of our sun, how do we tell that the rest of the planets and stars are not anti-matter planets and anti-matter stars?

Re:How do we know (2, Insightful)

Anonymous Coward | about a year ago | (#43536855)

Well, let me start by saying I don't know anything about this field. However, it seems to me that the interstellar medium is that kind of combination of really close to a vacuum and really big that still allows for quite a lot of particles out there hitting the edge of our solar system (I believe we're close to (or already are) getting actual measurements from probes we've sent out that have already left or will soon leave the solar system). Where these collisions occur, we'd expect matter-antimatter pairs to self-annihilate, and we could observe that. Since we don't, then the interstellar medium is made of matter. Likewise, if there were some antimatter stars out there, there would be a boundary between antimatter and matter in the interstellar medium and we could see the self-annihilations through observation. Maybe there are whole antimatter galaxies out there, but then again, we have discovered instances of galaxies that are colliding or have collided. Similar to stars passing through the interstellar medium, it seems we would be able to observe the matter-antimatter annihilation in at least some if they were in equal proportion.

Re:How do we know (1)

Brucelet (1857158) | about a year ago | (#43536909)

If there were large pockets of matter and anti-matter in different places, then there would be boundaries between them where annihilations are frequent. We observe no such boundaries.

Re:How do we know (1)

wisnoskij (1206448) | about a year ago | (#43536987)

But matter grouts together with indistinct borders that are not often crossed.

We are in the The Milky Way galaxy, it is probably fair to say that it is made of a vast majority of matter.

But how do well know that the Andromeda Galaxy is not made of a vast majority of antimatter.

Re:How do we know (1)

thrich81 (1357561) | about a year ago | (#43536951)

Read the AC comment before mine, it says about about what I was going to say. Certainly within galaxies and galaxy groups, there are enough interactions that we would see the results of the matter-antimatter annihilation if there were significant amounts of both, especially gamma rays at the energy of electron-positron annihilations. And many cosmic ray particles come from a long ways out, maybe even intergalactic, I think -- if there was a lot of antimatter out there we would see more antimatter in the incoming cosmic rays. Actually the AMS experiment on the ISS is directly measuring the presence of antimatter (mostly positrons) in the cosmic rays which make it to the vicinity of the earth. They aren't seeing much -- certainly not enough to support the presence of antimatter stars, gas, etc in our galaxy.

I don't get it (0)

Anonymous Coward | about a year ago | (#43536715)

Isn't there required to be more matter than antimatter in the universe? Otherwise the universe wouldn't exist because equal parts of matter and antimatter would annihilate each other and we'd just have a bunch of energy and no matter or anti-matter.

 

Re:I don't get it (0)

Anonymous Coward | about a year ago | (#43537161)

It depends how it's distributed. Obviously matter and anti-matter has to be close to annihilate.

Re:I don't get it (1)

wonkey_monkey (2592601) | about a year ago | (#43537225)

The universe would still exist even if it was empty; there'd just be no-one around to observe it (unless you want to get ridiculously philosophical about that). So no, it wasn't required to be that way, it's just lucky for us that it was.

There may well be other universes (sidebar: there are several different classes of things you can call "universes") where there is no matter or antimatter, but there are probably no conscious beings in there.

Re:I don't get it (2)

femtobyte (710429) | about a year ago | (#43539333)

Yes, from an "anthropic principle" perspective you've pretty much got to somehow end up with a universe with a matter/antimatter imbalance in order to have folks to see it. The interesting physics question, however, would be to understand how said necessary matter imbalance was produced. For example, perhaps matter and antimatter behave exactly the same, and we're just in a local "bubble" where early-universe statistical fluctuations coughed up a bit more matter. On the other hand, maybe we can find differences in the properties of matter and antimatter (which experiments like this indicate) that might allow one to be preferentially produced over the other.

Warning to non-western members: (0)

Anonymous Coward | about a year ago | (#43536763)

"How should we make it attractive for them [young people] to spend 5,6,7 years in our field, be satisfied, learn about excitement, but finally be qualified to find other possibilities?" -- H. Schopper

https://secure.wikimedia.org/wikipedia/en/wiki/Spin_(public_relations)#Techniques

And a warning besides PR spin to non-western members:

"The cost [...] has been evaluated, taking into account realistic labor prices in different countries. The total cost is X (with a western equivalent value of Y) [ahol Y>X]

forrás: LHCb calorimeters : Technical Design Report

ISBN: 9290831693 http://cdsweb.cern.ch/record/494264

CP violation (1)

VAXcat (674775) | about a year ago | (#43537305)

Matter...Anti-Matter...I'm the guy with the gun.

Meanwhile.... (2)

moeinvt (851793) | about a year ago | (#43537413)

Meanwhile, in a parallel universe: "...experiments at the LHC are seeking to cast light on this dominance of antimatter over matter."

Re:Meanwhile.... (2)

jfengel (409917) | about a year ago | (#43537997)

Except they call it the CHL.

Re:Meanwhile.... (1)

Anonymous Coward | about a year ago | (#43538187)

No, the headline would be exactly the same. THAT's curious.

Load More Comments
Slashdot Account

Need an Account?

Forgot your password?

Don't worry, we never post anything without your permission.

Submission Text Formatting Tips

We support a small subset of HTML, namely these tags:

  • b
  • i
  • p
  • br
  • a
  • ol
  • ul
  • li
  • dl
  • dt
  • dd
  • em
  • strong
  • tt
  • blockquote
  • div
  • quote
  • ecode

"ecode" can be used for code snippets, for example:

<ecode>    while(1) { do_something(); } </ecode>
Create a Slashdot Account

Loading...