Since the first exoplanet was identified in 1992, astronomers have confirmed the existence of nearly 1,900 planets beyond our solar system. The sheer number of planets increases the statistical probability that Earth-like planets will be found. Some estimate that there are around 140 habitable planets in our stellar neighborhood within 33.6 light years of Earth. Many astronomers estimate that we’ll find a life-bearing planet within 25 to 30 years, or maybe tonight, if we know what to look for.

The upcoming 10YSS symposium will focus on both the pragmatic and more theoretical elements of such a discovery: How do we find Earth 2.0? How do we confirm evidence of life? If we find evidence of intelligent life out there, how do we announce it to the world? How will the people of Earth 1.0 react?

“How do you finally decide, ‘Eureka, we found it?’” said Mae Jemison, a former NASA astronaut and the principal for 100YSS. “What are the compelling signs of finding another planet outside of our solar system that indisputably is terrestrially evolved, with earth-like evolved lifeforms? … What would happen if we could identify it [as Earth 2.0]? How does that change us?”

Jill Tarter, a former director of the Center for SETI Research who was present at the Green Bank observatory during the 1997 incident, said the first and most important step is to verify that a suspected signal from an intelligent source is indeed from another star system. “We worry, being in California, about all those post-graduates and Caltech students deliberately trying to fool us simply because they can,” said Tarter. Before any public announcement, “it should get verified independently” so as not to undermine SETI’s credibility.

The radio signal they’re looking for will stand out from cosmic radiation background noise—but so do signals from satellites, ground interference, and possibly natural but unknown astronomical phenomenon. If the signal occupies only a narrow band of frequencies, however, that separates it from natural cosmic emissions, suggesting a deliberate signal. Turning the radio telescope’s dish slightly from the signal’s apparent source can determine its distance: If the source is nearby, the signal will slowly fade. If it’s coming from a distant star, the signal will drop off sharply.

If all signs indicate that the signal is coming from another star, the astronomers contact other observatories or research organizations that subscribe to the Post-Detection Protocols to confirm a) that the signal exists, and b) that it’s likely coming from an intelligent source. If the other groups confirm the the signal, the original astronomers sound the alarm, alerting their national authorities of the discovery and sending an International Astronomical Union “telegram”—these days, an email—to observatories around the world. The guidelines also account for the United Nations’s 1967 Space Treaty, which calls for member states to notify the U.N. of their space-exploration activity—under the Protocols, the discovering astronomer alerts the Secretary General to the discovery, as well as a number of other international bodies.