Dark Matter 4: What is Dark Matter made of? - The search for WIMPS In my last post, I talked about h
Dark Matter 4: What is Dark Matter made of? - The search for WIMPS In my last post, I talked about how we can see the effects of dark matter not just in galaxies, but in the wider Universe as well. Gravity pulls the galaxies into a ‘cosmic web’ pattern - called galactic filaments. Now we are sure that there is more mass in the universe than we can see, we can start to think about what this extra mass actually is. Obviously, it must be either very difficult or impossible to see with light, and it must be very heavy. This shows that it is not baryonic or 'normal’ matter - stuff made out of protons and neutrons that we can see all around us in everyday life. Normal matter can interact with light, and this is why we can see it - it reflects and diffracts light into our eyes. If a dark matter particle exists, then it shouldn’t interact with light at all, and this is why can not zoom in with a telescope and actually see it. It makes sense then to assume that dark matter is not 'normal matter’ and must be made out of something more exotic. We know that normal matter is made of atoms which can be split up into particles, so can we get 'dark atoms’ made up of 'dark particles’? The first image I have included shows a few types of particle that dark matter could be made out of. Out of all of these, the most likely theory seems to be that dark matter is made out of a new type of particle called a Weakly Interacting Massive Particle (WIMP). These basically do what they say on the tin - they don’t interact with light very much, and they are really heavy (up to 1000 GeV!). The second image shows the Standard Model of Elementary Particles - a list of all the different types of particles we have found so far. If WIMPs do exist then they will have to fit into this model somewhere, which is why it has been suggested that they are a type of neutrino (see the bottom row). This is why the hunt for dark matter particles is really on, and scientists at CERN are hopeful that they may be able to find something when the accelerators are turned on later this year. But if a dark matter particle can’t be found, what happens then? Well dark matter might not exist and we might have to find another theory to try and explain it all! More to come in the next post! -- source link
#physics#astrophysics#standard model#particle physics#astronomy#science