Why is the search for dark matter in space significant, and how could supercooled water help physicists to find out more?
Matthew M. Szydagis, an assistant professor of physics at the University at Albany, State University at New York was partially inspired by the Disney movie Frozen and YouTube videos of supercooled water, to use this method to search for dark matter in space.
Creating supercooled water
Clean water which is low in impurities such as dust particles can be cooled below its freezing point without freezing, when placed in a smooth enough container, according to Szydagis.
He said: “This is called ‘supercooling’ and is similar to how water can be easily superheated in the microwave, essentially heated above its boiling point without actually boiling. It’s simply the reverse. The water ends up, in either of these cases, in a state known as ‘metastability,’ neither unstable nor quite stable either.”
An example of one of the many tutorial videos for crystallising supercooled water into ice at home:
The search for dark matter
The team created a new detector based on supercooled water, which has been called the “snowball chamber”.
Szydagis explained: “We managed to discover a new property of supercooled water. To our great surprise, we found that some particles (neutrons) but not others (gamma rays) trigger freezing. Since this is basic research that has never been done before, there was no guarantee it would work. It was a ‘let’s try it and see’ approach — the scientific method in its most basic form. Not only do we have a new detector of fundamental particles, but potentially of dark matter because neutrons are thought to emulate it.”
Szydagis added: “All of my work is motivated by the search for dark matter, a form of matter we’re sure is out there because we can observe its indirect gravitational effects. It makes up a significant fraction of the universe, but we have yet to uncover direct, conclusive and unambiguous evidence of it within the lab.”