It could be 1,500 years before make with aliens. Astronomers joined two about the of life on planets. One theory is the Fermi Paradox. This states that while of Earth-like planets exist in our , not has made contact . The other is the mediocrity principle. This suggests that because there is on Earth, it will exist on Earth-like planets in the universe.
Researcher Evan Solomonides said: "We haven't heard from aliens yet, as is a big , but that doesn't mean no one is out ." He said may not have decoded the we sent. They would also need to decode 3,000 human . Signals from Earth have reached 8,500 ; our Milky Way has 200 stars. Solomonides said: "If we stop listening or looking, we may miss the signals, so we keep looking."