Antimatter, the mirror opposite of normal matter, is strange stuff. Particles and atoms of antimatter have the opposite charge of their regular counterparts, and they behave accordingly. When the two collide, you don't want to be nearby--they annihilate each other in a flash of light.
Physicists wonder whether they also respond differently to gravity--does antimatter "fall" up? Does it weigh the same as regular matter? Does it exhibit anti-gravity? To find out, physicists at CERN and Lawrence Berkeley National Laboratory went Newton on it and dropped some.
It would make sense if gravity is the same for antimatter and regular matter. But there is no direct evidence proving this. Scientists who work with CERN's ALPHA experiment, an antimatter experiment, tried to measure it in a somewhat roundabout way. First the researchers made antimatter, by joining antiprotons with positrons--the opposites of protons and electrons, respectively--and producing atoms of antihydrogen. The anti-atoms were suspended in a strong magnetic field so they wouldn't touch the walls of their container, annihilating themselves and their counterparts.
Then the researchers turned off the magnetic field, allowing the antimatter to free-fall. If they knew where the anti-atom was when the field shut down, and they knew its velocity while hanging out in magnetic limbo, they could calculate how long it took to fall, and thereby measure the effect of gravity. Antihydrogen did not behave strangely, they found.
The results were very unclear, though. The magnetic fields don't turn off instantly; it takes about 30 thousandths of a second to dissipate. When you are talking about individual atomic particles, that can add up to a long time. And individual flashes of annihilation happened throughout the antimatter trap, confusing the results. It could take several years to achieve the statistical accuracy physicists would need to prove how antimatter behaves with gravity.
The good news: The technical achievement is the real breakthrough here. It's the first time anyone has directly measured the effect of gravity on free-falling antimatter. "Is there such a thing as antigravity? Based on free-fall tests so far, we can't say yes or no," Joel Fajans of Berkeley Lab said in a statement. "This is the first word, however, not the last."
A paper describing the experiment appears this week in Nature Communications.
It makes sense to me that if gravity is the result of the bending of space which consists of no particles then anti-particles should behave the same as regular particles.
Cool article from PoPSCI.
Thank you for the geewiz I did not know that information!
Why would charge difference matter for gravity.
The antimatter atoms still got mass. It got speed and momentum unless its perfectly still.
so e=mc2 applies. It has energy so it has mass regardless of speed. And gravity is as far as we know, directly related to the mass and distance.
In theory - an isolated region of space could even harbour a complete antimatter galaxy, complete with stars, planets and even life.
We know that matter-antimater dont go together.. but how about dark matter? How would it possibly react to the presence of antimatter
Anti-matter already reacts with dark matter... and you dont use theory unless your hypothesis has enough evidence.
If matter is the opposite of antimatter does it fall down -yes.
If antimatter is the opposite of matter does it fall up -yes.
The Sublunary Sphere is the pivot between the two scales.
Is gravity bending space, or the exchange of gravitons? How *would* antimatter couple differently to gravity than normal matter?
The same evidence that verified Special Relativity almost a century ago demonstrated that massless photons couple to gravity. Should antimatter be different?
Now all we need is a new Arms Race. Before we know it, we'll have anti-matter bombs and then anti-matter bullets. Worked for nuclear energy!
@lifestream @sarahsetzer No one knows what dark matter is, otherwise it wouldn't be "dark". It's just the solution to why galaxies don't move quite the way they should. That doesn't mean it's exotic or magic, it just means it doesn't emit light.
Also I'm pretty sure we don't have any.
Assuming the Higgs boson imparts postive mass, an anti-Higgs boson, still to be discovered, should make things fall up.
If dark matter accounts for most of the matter in the universe and there is anti-matter in the universe doesnt it react with it, being that the dark matter is around all other matter, including anti-matter.