Looking at the Earth Through Extraterrestrial Eyes

From our leakage radiation, an alien would be able to tell quite a bit about the planet, including the length of our day, the size of the planet, and even the fact that we don’t have any global governance.
  • Transcript


Question: If you were an extraterrestrial looking at Earth, what would you think? 

Jill Tarter: From our leakage radiation, our broadcast television and radio you can tell some amazing things about the planet and the technological species that occupy it. You can certainly get the length of our day. You can get an estimate of the size of the planet. You can even deduce that we don't have any kind of global governance. That is because in every region of the planet, television stations and radio stations are assigned frequencies that are specific to the different international telecommunications union regions around the globe and those frequencies are similar, but not exactly the same, so if you were getting the broadcast transmission leakage from this planet as our planet rotates and another region comes into view on the horizon you would see that those transmission frequencies shift a little. In 24 hours they’re back to that same pattern and you would probably deduce that the whole planet was not operating as a single geopolitical unit. So we talked a little about... and we often think about what is going to happen if we detect a signal. Certainly the SETI Institute is part of a group of scientists who are working on the project who have said, well you know if we detect a signal we’re certainly going to tell the world, but we’re not going to transmit back until there has been some global consensus that we should. Then we figure out who should speak for Earth and what should we say and that is all great... really hard to understand how we’ll do it. And at the same time if you announce that you’ve detected a signal and you give the nature of the signal you let other people know what you’ve found, then it’s human nature. Anyone who can have access to some kind of a transmitter is going to use it and they’re going to say whatever it is that they want to say. Whatever we might want to have in terms of this high minded intellectual response. And Freeman Dyson, a physicist in Princeton at the Institute for Advanced Studies, kind of chuckles every time we get into this topic. He said, “Think about it. That un-orchestrated, chaotic, cacophony that would emit from the planet after the detection of a signal.” He said, “Wouldn’t that be about the best representation of 21st-Century Earth that you could imagine?” And I have to agree that he is right. Nevertheless, scientists that we are, we try and plan for that. There is a piece of our website at the SETI Institute, at SETI.org, a project called "Earth Speaks." One of our scientists is trying to get people—particularly young people—to tell us what message they would like to send if we were going to send a message to another technologic civilization and what he is looking for are cultural universals, the kinds of ideas that come from every society around the planet and it’s a way to try and see what, at the core, it is to be human and what we’d like the rest of the universe to know about us. 

Recorded on June 3, 2010
Interviewed by Jessica Liebman