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CERN Begins New Antimatter Gravity Experiments (phys.org)
An anonymous reader quotes a report from Phys.Org: We learn it at high school: Release two objects of different masses in the absence of friction forces and they fall down at the same rate in Earth's gravity. What we haven't learned, because it hasn't been directly measured in experiments, is whether antimatter falls down at the same rate as ordinary matter or if it might behave differently. Two new experiments at CERN, ALPHA-g and GBAR, have now started their journey towards answering this question.
After months of round-the-clock work by researchers and engineers to put together the experiments, ALPHA-g and GBAR have received the first beams of antiprotons, marking the beginning of both experiments. ALPHA-g began taking beam on October 30, after receiving the necessary safety approvals. ELENA sent its first beam to GBAR on July 20, and since then the decelerator and GBAR researchers have been trying to perfect the delivery of the beam. The ALPHA-g and GBAR teams are now racing to commission their experiments before CERN's accelerators shut down in a few weeks for a two-year period of maintenance work.
After months of round-the-clock work by researchers and engineers to put together the experiments, ALPHA-g and GBAR have received the first beams of antiprotons, marking the beginning of both experiments. ALPHA-g began taking beam on October 30, after receiving the necessary safety approvals. ELENA sent its first beam to GBAR on July 20, and since then the decelerator and GBAR researchers have been trying to perfect the delivery of the beam. The ALPHA-g and GBAR teams are now racing to commission their experiments before CERN's accelerators shut down in a few weeks for a two-year period of maintenance work.
".. whether antimatter falls down .."
Or maybe it falls up?
What they measured there was the mass, which for masses that small can be measured by applying a known force while it is moving (typically through an orthogonal magnetic field) and measuring how quickly its trajectory is altered. How much inertia it has, however, does not necessarily mean that it reacts to gravity the same way as normal matter.
File under 'M' for 'Manic ranting'
Can I make an obvious observation.
There are lots and lots of attraction only 'forces' in nature. They're not really forces, they're the net effect of dipolar forces.
Example 1: Stick magnets in a bag, shake it, the magnets will organize to stick together. The NN and SS poles could repel but they always end up stuck together as NS NS.... The forces push apart similar poles, and attract different poles and the net effect is an attraction only force.
Example 2, think of a crystal forming. At the bind site for the molecule, the force is zero. If you squeeze the crystal the force goes negative and the crystal pushes back. But beyond the nano level, the force is attraction only, and reduces according to the square rules, just like gravity. (Think about this force for a moment, as it gets closer, the force increases, at super small distances it decreases to zero, then goes negative. I could label this force 'crystal strong force' or some other name and model it as if its a real force with magic properties, but to do so would be dumb).
Example 3, my spinning dipoles always organize to have a net attraction force. I found they clump like matter, and concluded that gravity isn't caused by a magic 'mass' property, gravity is the measure of this net clumping ability on a large scale. Mass is simply the potential to clump.
Example 4, Do the same as 1 with more complex magnets with multiple poles, they will form magnetic crystals when you shake them up.
So, the lack of an anti-gravity force points to gravity being one of these net organizational dipolar forces.
Which means you won't find an anti-gravity.
It's also why I say you cannot assume a black hole can suck in matter forever, because you don't know how gravity will behave at super short distances. If its a net organizational dipolar force, it goes negative at super small distances. Just like the crystal case, just like my spinning dipole case.
How much inertia it has, however, does not necessarily mean that it reacts to gravity the same way as normal matter.
General Relativity is based on the assumption that inertial mass and gravitational mass are equivalent. IM=GM is one of those things, like P!=NP, "No FTL", and the Riemann Hypothesis, that everyone assumes, so a confirmation will have little effect. However if the answer is IM!=GM, physics will be turned upside down.
Which would be pretty cool.
There is possibility it falls down at different rate. If it falls up, then how is GR going to describe this behavior ?
Neither falling up nor falling at a different rate is consistent with GR.
We can tell by the recoil effect in nuclear reactions that the inertial mass of particles and anti-particles are identical. GR says the gravitational mass must also be identical. So if it isn't, GR would be overturned, and we would need some new theories to explain how the universe works.
Don't hold your breath. If this experiment shows that AM "falls up" it is more likely to be an equipment failure than a correct result. It is that unlikely.
Orange Man Bad!
[ removes sunglasses ] ... anti-climatic.
It must have been something you assimilated. . . .
It's one of those things, "You don't know until you try." I think everyone has a low expectation of finding that anti-matter behaves differently with gravity, but it's an experiment we can do, so why not do it?
We know there is something missing here (that is, why is matter so much more common than anti-matter?) so we need to keep experimenting, process of elimination, until we find the answer.
"First they came for the slanderers and i said nothing."
This seems extraordinarily unlikely to produce any surprises. Is there any theory or experiment in matter with an opposite electrical charge has anti-gravity? They're distinct fundamental forces.
The quantum mechanical model of antiparticles is that they are normal particles which are travelling back in time. It's a bit nonsensical from a non quantum mechanical persepective and it's not time travel as you might think of it. But if you time-reverse an electron and calculate how it behaves it behaves like that particle we can observe known as the positron.
It makes other things neat. For example accelerating electrons emit photons, or the emission of a photon causes the electron to accelerate. So far so good. If you take the time travel model then annihalation is an example of that. An electron and positron meet and get drstroyed emitting a photon. Or an electron amits a photon and changes direction in time rather than space and goes backwards as a positron. From a forward time point of view that looks like an electron and positron coming togther.
Pair production and annhilation just becomes a single electron whizzing round in circles in time.
IOW in the rather peculiar world of quantum mechanics a lot of observable things are modelled to within measurement error as time-reversed particles. Sure it's a mathematical abstraction but it works.
Quantum mechaices has no model of gravity. If an electron travelling forwards in time falls into a graviy well what do you think a time-reversed one might do? GR says it has mass so it's attracted and falls down. That seems to be the most popular view. But QM says it's time reversed so... what?
The answer is we won't know for sure.
SJW n. One who posts facts.