How Do Antennas Work?

An antenna is just a long column with a bunch of electrons in it that we can control there wiggling. And when they do that wiggling, they generate photons at the frequency that they are wiggling. So if your electrons are moving at four point two megga hurts, for example, then you will be generating photons at that frequency. But there aren't like antennas out there in space sending us these messages at least we haven't received any yet. Instead, what we ore natural objects like stars, or clouds of gas, or quasars, or black holes, or accretion disks,. These things are sending us radiation. How does that happen? If there