# CERN experiment proves gravity pulls antimatter the way Einstein predicted

In sci-fi, antimatter is the opposite of all the matter around us. Does that mean it should fall up? Not at all, scientists at Europe's largest sub-atomic physics lab have proved for the first time. The result was predicted by Einstein's Theory of General Relativity more than 100 years ago, though getting experimental evidence …

1. A neat explanation of a relatively complex problem. Well done to both the investigators and journalists for making it readable!

2. Drat. That rules out my plans for an anti-gravity drive based on a magnetically bound pot of antimatter.

Now what am I going to do with it?

1. Now what am I going to do with it?

Everything can be a dildo if one is brave enough.

1. Resulting in an anticlimax?

1. Perhaps this explains the lack of antimatter in the observable universe. It's all been converted into anticlimaxes.

The ration of anticlimaxes to climaxes is known to be similar to the ratio of observable positrons to electrons.

1. It's all a tad disappointing.

2. There once was a lady named Jill ...

2. #### Now what am I going to do with it?

《That rules out my plans for an anti-gravity drive based on a magnetically bound pot of antimatter. Now what am I going to do with it?》

So not Cavorite then.

Still a pot of say 1.0 kg of antihydrogen when "reacted" hydrogen very slowly should make a pretty decent rocket engine.

Slowly as 1kg x (300,000km/s)^2 an inconvenient number of Joules :)

1. #### Re: Now what am I going to do with it?

It's worse. To get the SI unit Joule, you should use m/s for speed, so (3x10^8 m/s)^2 = 9x10^16 joules.

To put it in sensible units, you'd have to eat about 67 billion tonnes of oats for the same calorific intake.

1. #### Re: Now what am I going to do with it?

> you'd have to eat about 67 billion tonnes of oats

Converting it into oats based units presumably makes it easier to then calculate things in terms of horse power years.

1. #### Re: Now what am I going to do with it?

Time for an update to the Reg Standards Soviet.

3. Ah, but as hydrogen balloons rise the fact that antihydrogen falls proves that it does do the opposite.

Mine's the lab-coat hanging upside down.

4. #### CERN experiment proves gravity pulls antimatter the way Einstein predicted

> Ah, but as hydrogen balloons rise the fact that antihydrogen falls proves that it does do the opposite.

Ah, but to really prove that wouldn't you need to make a balloon... err... anti-balloon filed with anti-hydrogen and see what happens?

But then again maybe it would have anti-buoyancy to complicate things...

5. Just from half remembered physics books, this makes sense to me. Antimatter is a misnomer. Antimatter is still matter. It isn’t a case that Antimatter + Matter = 0 (because the annihilation produces energy - lots of it, and if antimatter was truly the opposite of matter the annihilation would produce exactly nothing.)

‘Antimatter’ is just matter with opposite spin.

1. #### More to the point

More to the point, General Relativity views gravity as a space-time distortion dependent on the local energy density. It does not matter whether that local energy density is in the form of mass or energy, or a mix.

2. #### ‘Antimatter’ is just matter with opposite spin.

"Opposite charge" would be better than "spin" ... at least for sufficiently general notions of charge (e.g. arguably dated usages such as where lepton number <-> lepton charge).

The problem with using "spin" is that - for the symmetry-based "spin", unless the object is spin zero, there is both a total spin and spin components; and the total spin is always positive, and the sign of the component is irrelevant to the particle/antiparticle determination.

Using "charge" in the generalized sense is also confusing, given that you might conflate/confuse it with (only) electrical charge; and not the specific implication of "oppositely charged to the normal (i.e. non-anti) version of the particle".

1. #### Re: ‘Antimatter’ is just matter with opposite spin.

In general, using any term in the general sense generally leads to general misunderstanding.

6. #### If it's energy...

...It has the property we call 'gravity.' Therefore, it's no surprise that anti-matter, which is energy, has the same gravity as its matter counterpart.

I wish the realization that all energy has gravity would penetrate and become a universal understanding. Physicists make a lot of incorrect conjectures assuming the opposite. Call it "anti-physics." Can we move along please?

7. #### The results are thus far in conformity with the predictions of General Relativity

This is the opposite of the long-proved corporate theory of Relative Generality, where it has long been known that anti-managers fail upwards.

8. If you get enough anti-matter together everything goes up eventually, often with a large flash of light and the destruction of a large area centered around the storage site

1. #### often ?

how "often" did you observe that large flash of light ? I'd be interested of the site(s) where this can be observed "often"

1. #### Re: often ?

It was only observed once per site, per OP's description. To observe it often, you have to find a number of sites where it hasn't happened yet, and wait.

2. The problem is (if I remember the Simon Singh Radio 4 series "Five Particles" correctly) - we've only made enough antimatter to keep a lightbulb going for a matter of minutes...

1. #### we've only made enough antimatter ...

Hence the need for ever better and more efficient lightbulbs!

1. #### Re: we've only made enough antimatter ...

Or four candles.

3. Technically, the same thing happens to matter.

9. #### new matter

After anti-matter and dark-matter, scientist have discovered a new type : the doesn't-matter, which doesn't have any interaction with the universe whatsoever.

1. #### Re: new matter

We've known about the SEP for decades now, but most people only catch a glimpse of it out of the corner of their eye.

10. #### Where is the antimatter?

Could I just say for one moment that I have a new theory about the antimatter? Yes my word you may well ask what it is, this theory of mine. Well, this theory that I have – that is to say, which is mine – … is mine.

It's hiding in the closet.

– A. Elk (Miss)

11. #### Dark Matter? Anti-Matter?

So, we can't explain the expansion of the universe without more matter than we can account for. We think we know that the universe started out with an equal amount of "normal" and "anti" matter except we can't find the expected anti-matter. So can someone explain why we think dark matter is a thing and maybe it's not just lots of anti-matter out where we can't see or detect it? I'm no astro/nuclear/particle physicist and I'm having trouble getting my head around this.

1. #### Re: Dark Matter? Anti-Matter?

If there was a load of anti-mater in the universe we would certainly be able to 'see' as it interacts with normal mater quiet well. Dark mater on the other hand, if is actually exists, keeps itself to itself as far as interacting with the stuff we can see. Oh, and by the way, we can 'see' quiet a long way, almost back to when the first stars were forming.

p.s. As for an equal amount of mater and anti-mater at the beginning, still just a theory. There is some wiggle room with the CERN experiment which might yet show that anti-mater behaves differently than mater in some crucial way which might account for it's lack of existence in the universe we observe. Perhaps it might go some way to explain why less anti-mater than matter formed during the big bang leaving the mater we can see. Or, perhaps we are just wrong about the big bang and all that.

12. #### Mind over Mater

Mind / Matter = We don't mind and you don't matter

13. Antihydrogen is tricky to study. Whenever it comes into contact with regular matter, it disappears in a puff of energy.

A puff? According to Dan Brown novels, it should be an earth shattering kaboom.

Must try again.

:)

14. #### Spectrum of Antihydrogen

One line so far, see https://www.nature.com/articles/s41586-018-0435-1

"The transition frequency at a field of 1.033 tesla was determined to be 2,466,051.7 ± 0.12 gigahertz (1σ uncertainty) and agrees with the prediction for hydrogen to a precision of 5 × 10−8."

What if we are looking at distant galaxies with normal spectra, but they are entirely antimatter? How could we tell the difference? If the matter and antimatter separated out in the early universe, then maybe there is the same of each, just isolated into galaxy or galaxy cluster clumps.

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