<p>It would look very similar, but tiny differences are suspected, see e.g. <a href="http://home.web.cern.ch/about/updates/2013/04/lhcb-experiment-observes-new-matter-antimatter-difference" rel="nofollow">this LHC experiment</a>.</p>

<p><a href="http://home.web.cern.ch/topics/antimatter" rel="nofollow">Here a list of more antimatter experiments at CERN</a>.</p>

<p>See also <a href="http://en.wikipedia.org/wiki/CP_violation" rel="nofollow">CP violation on Wikipedia</a> hinting towards tiny differences between matter and antimatter.</p>

<p>Immediate consequence: The CP violation parameter of the <a href="http://pdg.lbl.gov/2008/reviews/kmmixrpp.pdf" rel="nofollow">CKM matrix</a> in <a href="http://en.wikipedia.org/wiki/Cabibbo%E2%80%93Kobayashi%E2%80%93Maskawa_matrix" rel="nofollow">this Wikipedia article</a> would be different, because of different quark generation probabilities.</p>

<p>If you also reverse time, you'll get to the <a href="http://en.wikipedia.org/wiki/CPT_symmetry" rel="nofollow">CPT theorem</a> (Charge, Parity, Time). Matter and antimatter are thought to be symmetric in this sense.</p>

<p>Or to state it with simpler words: Antimatter behaves like matter travelling backward in time.</p>

CC BY-SA 4.0
2018-10-09T06:58:28.633Z
`Antimatter behaves like matter travelling backward in time` -  can you please explain more specifically what do you mean by this?
tarit goswami
CC BY-SA 3.0
2014-01-31T15:48:22.697Z
2014-01-31T16:53:36.793Z
2014-01-31T16:53:36.793Z
Gerald
<p>...what would be the immediate consequences?</p>

<p>Or putting it better, if (from big-bang or whathever), the universe were always made of what we call Anti-matter what would it be?</p>

<p>The scientists of this universe would call 'Matter' 'Anti-Matter'.</p>

<p>Will the universe looks like exactly the same? By "looks", I mean the laws of Physics, the constitution of the universe with its superclusters of galaxies containing clusters containing galaxies and so on...</p>

<cosmology><antimatter>
If we "turned universe upside-down" and changed all matter to anti-matter instantly
Bruno Alessi
# If we "turned universe upside-down" and changed all matter to anti-matter instantly

(Asked by: username_0 on 2014-01-31)

...what would be the immediate consequences?

Or putting it better, if (from big-bang or whathever), the universe were always made of what we call Anti-matter what would it be?

The scientists of this universe would call 'Matter' 'Anti-Matter'.

Will the universe looks like exactly the same? By "looks", I mean the laws of Physics, the constitution of the universe with its superclusters of galaxies containing clusters containing galaxies and so on...

**Tags:** cosmology, antimatter

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## 1 answers

### Answer by username_1 on 2014-01-31. Score: 5 | Accepted answer

It would look very similar, but tiny differences are suspected, see e.g. [this LHC experiment](http://home.web.cern.ch/about/updates/2013/04/lhcb-experiment-observes-new-matter-antimatter-difference).

[Here a list of more antimatter experiments at CERN](http://home.web.cern.ch/topics/antimatter).

See also [CP violation on Wikipedia](http://en.wikipedia.org/wiki/CP_violation) hinting towards tiny differences between matter and antimatter.

Immediate consequence: The CP violation parameter of the [CKM matrix](http://pdg.lbl.gov/2008/reviews/kmmixrpp.pdf) in [this Wikipedia article](http://en.wikipedia.org/wiki/Cabibbo%E2%80%93Kobayashi%E2%80%93Maskawa_matrix) would be different, because of different quark generation probabilities.

If you also reverse time, you'll get to the [CPT theorem](http://en.wikipedia.org/wiki/CPT_symmetry) (Charge, Parity, Time). Matter and antimatter are thought to be symmetric in this sense.

Or to state it with simpler words: Antimatter behaves like matter travelling backward in time.

> **Comments:**
> **username_2**: `Antimatter behaves like matter travelling backward in time` -  can you please explain more specifically what do you mean by this?  

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