Gap Fill - Level 6

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   billions      equation      existing      galaxy      galaxy      least      messages      other      paper      physicist      place      should      signals      species      them      theory      there      typically      waves      yet  
Scientists say it could take at 1,500 years before humans make contact with of aliens, or for them to communicate with or find us. Astronomers from Cornell University in the USA combined two theories about the possibility of life existing on planets to form a new . One of these theories is the Fermi Paradox described by Enrico Fermi in 1950. This states that while of Earth-like planets exist in our , not one has made contact with Earth . The other is the mediocrity principle, which suggests that because there is life on Earth, it will exist on Earth-like planets throughout the universe.

Study author Evan Solomonides will soon present a research on his . He said: "We haven't heard from aliens yet, as space is a big , but that doesn't mean no one is out ." According to Solomonides, extraterrestrials could have received from Earth. However, he proposes that ET would not have been able to decipher . He said they would need to decode the light into sounds and analyse 3,000 human languages to understand any . He said that signals from Earth have only reached about 8,500 stars and that the Milky Way alone contains 200 billion stars. He added: "If we stop listening or looking, we may miss the signals, so we keep looking."

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