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