• Question: Could there be a whole other set such as dark energy variations of both matter and antimatter?

    Asked by anon-345100 on 8 Dec 2022.
    • Photo: Joel Goldstein

      Joel Goldstein answered on 8 Dec 2022:

      At the moment we don’t know much about dark energy at all, although we think it is probably something completely different from matter and antimatter. We don’t even know if it has particles associated with it

      But there are definitely other theories that predict whole new sets of matter and antimatter particles. One of the best known is Supersymmetry, which predicts that for every particle we know about now (matter or antimatter) there is a partner particle with the same charge but different spin.

      Another possibility is that there could be extra generations of matter particles. For example, at the moment we know about the electron, the muon (which has the same properties as the electron but is 200x more massive) and the tau particle (again the same properties as the electron, but about 3000x more massive). Some people have predicted that there could be more and more even heavier versions.

    • Photo: Patrick MacGregor

      Patrick MacGregor answered on 9 Dec 2022:

      This is a great question! Dark energy and dark matter are very mysterious to us at the moment – it’s a name for something we know very little about. But because we know that there is something there, we can start designing experiments to try and discover more about their properties. For example, we might be able to place a limit on how heavy these particles are based on what we do know about them. Therefore, if we are going to discover them, we will need to design experiments that is able to create particles with these masses.

      We also don’t know much about how they interact with matter — we know that gravity is involved, but we don’t know whether dark matter interacts with matter via the other forces. Similarly, dark energy can be present in Einstein’s theory of general relativity, but we don’t know how to match that with quantum mechanics.

      With so much that we don’t know, we have to be patient and try our best to understand how the universe works. We will make many mistakes and have a lot of frustrating experiments along the way, but we are hopeful that we will one day discover more about these two phenomena — perhaps you can join us and help us in this adventure!

    • Photo: Jonathan Edward Davies

      Jonathan Edward Davies answered on 12 Dec 2022:

      Maybe! We actually don’t know very much at all about “dark energy”- it’s just a label we give to an extra source of energy in the universe that we don’t know about. You may know that this is not a small amount of the “stuff” in the universe either- we think about 68%. At the end of the 20th century we discovered a mind-boggling fact- the universe is expanding! But this fact can’t be explained by what we know about radiation or matter (or anti-matter) or even dark matter. We then need some additional source of energy to work against the effects of gravity which will try to make the universe collapse instead and this is what we call “dark energy”.

      This is about as much as we can be sure of and working out what it is exactly is a big challenge for physicists in the future. You probably know of the world-famous equation e=mc^2, which means that by destroying a small amount of mass you can create quite a large amount of energy- like in a nuclear weapon. It also works the other way round and with a large enough amount of energy you can create some mass (new particles). So while we call it “energy”, it could very likely be explained by new undiscovered particles.

      One of the many things we are trying to do at big particle physics experiments like the Large Hadron Collider at CERN is to find new particles that could make up either dark matter or dark energy. However, it might be that these have huge masses, which would mean we might have to wait some time for good enough technology to allow us to make them. As has been said, we just have to be patient and keep our fingers crossed.

    • Photo: Edward Thorpe-Woods

      Edward Thorpe-Woods answered on 12 Dec 2022:

      Dark energy is a very mysterious phenomenon, we don’t really know much about it. It is the name we give to an unknown form of energy that affects the expansion of the universe on the largest scales- causing it to expand fast and faster rather than at a constant rate or contracting under gravity.

      It is different from dark matter (the invisible matter which makes up most of the mass of the universe), and antimatter (matter composed of antiparticles that have the same mass as standard particles, but opposite electric charge, and other differences in quantum numbers. Antimatter is also my research area! )

      However, antimatter can be used in some experiments by the BASE collaboration (also based at CERN) to look for cold dark matter particles called axions. In these experiments, BASE traps antiprotons (the antiparticle of the proton) and uses extremely sensitive detection systems to study its behavior. Any signals other than those produced by antiprotons may indicate the presence of axion-like particles