AboutKevin Johnson Expertise I will try to answer any question in physics, but I do not provide homework solutions or project ideas. I have some teaching experience at university level but I am also skilled at explaining things in simple terms.
My specialty areas are granular materials, computational physics, particle physics, quantum physics, econophysics and general physics.
Questions in GERMAN are welcome, too.
Experience I have graduated in physics, specialized in theoretical particle physics and quantum field theory, worked in the area of econophysics and am currently working on my PhD in granular materials and computational physics. I have some tutoring and teaching experience at University level.
Education/Credentials German Diploma in Physics (equivalent to M.Sc)
Question Hi, I'm curious, are there particles that contain no mass? By that I mean, is this proven or is it theory. I'm asking because I was taught in college that nothing could exceed the speed of light because it would be converted to infinite mass requiring infinite energy. But if there are particles that contain no mass, have we dodged this problem? Thank you for responding.
Answer Hello Marc,
Einstein's famous formula E=mc^2 expresses the equivalence of mass and energy: If you accelerate a massive particle further and further, i.e. you give it more and more energy, its mass also increases. Before a massive particle could reach the speed of light, its so called relativistic mass would go to infinity - which means a massive particle can never reach the speed of light.
What characterizes what scientists call "massive" particles are particles that have a non-zero rest mass, i.e. when they are at rest, they still have a mass (and the equivalent energy).
Some particles (like photons for example) only exist at the speed of light. They cannot exist at any other speed, let alone "at rest". They have zero rest mass. But since they carry energy, they also have the equivalent relativistic mass (according to Einstein's formula). But this relativistic mass is not infinite although they travel at the speed of light. This only works because they have zero rest mass.
I hope I could help you more than I confused you ;-)
