You know that old E=mc² equation? That’s actually only the simplified “rest” half of it. The full equation that relativity gives us says E²=m²c⁴+p²c². Meaning if it has energy, it definitely has mass, momentum, or both.
You know that old E=mc² equation? That’s actually only the simplified “rest” half of it. The full equation that relativity gives us says E²=m²c⁴+p²c². Meaning if it has energy, it definitely has mass, momentum, or both.