These astonishing claims by the US space agency were made during a conference this week in Washington.
Now NASA hopes to create a road map of the universe to search for alien life using some of the most advanced telescopes ever made.
Sara Seager, professor of planetary science and physics at the Massachusetts Institute of Technology in Cambridge, Massachusetts, said: “Some time in the near future, people will be able to point to a star and say, ‘that star has a planet like Earth’.
“Astronomers think it is very likely that every single star in our Milky Way galaxy has at least one planet.”
NASA’s quest to study planetary systems around other stars started with ground-based observatories, then moved to space-based gadgets like the Hubble Space Telescope.
And today’s modern telescopes can look at many stars and tell if they have one or more orbiting planets.
They can even determine if the planets are the right distance away from the star to have liquid water – the key ingredient to life as we know it.
NASA will launch its new space programme over the next few years and will include the Webb Space Telescope.
This state-of-the-art machine will lay the groundwork in the search for life on other planets.
It will be able to extend the search for oceans in the form of atmospheric water vapour on nearby planets that are similar to Earth in size and mass.
“This technology we are using to explore exoplanets is real,” said John Grunsfeld, astronaut and associate administrator for NASA’s Science Mission Directorate in Washington.
“The James Webb Space Telescope and the next advances are happening now.
“These are not dreams – this is what we do at NASA.”
NASA has already discovered more than 5,000 planets that could sustain life and many more could still be found.
“What we didn’t know five years ago is that perhaps 10 to 20 per cent of stars around us have Earth-size planets in the habitable zone,” says Matt Mountain, director and Webb telescope scientist at the Space Telescope Science Institute in Baltimore.
“It’s within our grasp to pull off a discovery that will change the world forever.
“It is going to take a continuing partnership between NASA, science, technology, the US and international space endeavors, as exemplified by the James Webb Space Telescope, to build the next bridge to humanity’s future.”