Want to experiment with some of the weirdest stuff in the universe from the comfort of your own home? An experiment at CERN is asking members of the public to analyse particle tracks over the internet, in an attempt to help answer one of the weirder questions in modern physics: whether antimatter falls up.
Although, for now, antigravity is confined to science fiction, antimatter is our best hope of finding an example in the real world. Difficult and expensive to study, physicists have yet to see how it responds to gravity. Some theories suggest antimatter will fall exactly like matter, and others indicate extra gravity-like forces that would pull down on antimatter even harder, but antigravity – and the idea that it might fall up – is not ruled out.
To answer the question, the AEGIS experiment at the CERN particle physics laboratory near Geneva, Switzerland, is preparing to shoot antihydrogen atoms at ordinary matter, causing both to annihilate and produce a host of other particles. These new particles will then travel though liquid, creating visible tracks, which can be analysed to reveal where the antihydrogen collision occurred. That will help determine whether gravity affects antimatter differently to normal matter.
Computer algorithms have been created that can, in principle, trace the tracks that particles leave behind. The trouble is they were originally designed to study neutrinos, which produce totally different tracks, so the algorithms need adapting.
The AEGIS crowdsourcing software asks you to watch short animations based on real particle annihilations and trace over any straight lines that could be particle paths. Physicists will then use the human-spotted tracks to update the algorithms' criteria for tracing out tracks. As people are very good at spotting patterns – like rows of dots that could be paths – the idea is that humans will flag up tracks that the software misses, or rule out false positives.
"It's a good test-bed to see whether we can get crowdsourcing to help us," says AEGIS spokesperson Michael Doser. "We want to see whether humans are better than algorithms."Science crowdsourcing is really becoming mainstream. To read more, click here.