Hello, assuming we can detect antimatter with some telescopic technique just like we can detect matter, is there any way to tell them apart? How would this be done?
That's not quite true. Because the chirality of an anti-particle is the opposite of its matter equivalent, its interaction under the weak force is slightly different. While the strength of the interaction is unchanged, any angular dependances of weak interactions will be reversed. This, however, can really only be seen in precision tests. So, there is nothing we could directly observe that would tell us that we're looking at antimatter.Anti-matter would behave exactly like regular matter until the two met. We deduce there is very little anti-matter in the universe because we do not observe such collisions, which would be hugely energetic.