A Nasa scientist has said that we are close to finding extraterrestrial life in the universe.

Astronomer Kevin Hand has said that the Goldilocks Zone, the habitable band around a star that can support liquid water as it is neither too cold nor too hot, is likely to harbour intelligent life.

Scientists believe that tidal flexing, an effect of the tidal forces between an orbiting natural satellite, and geothermal energy expands this habitable area to include Jupiter's moon Europa.

Speaking at the Palaeontological Society of Southern Africa's 18th biennial conference, Hand said: "For the first time in our history we have the tools and technology to do this experiment and go out to these worlds.

Although Europa is covered in thick ice, its smooth surface had led scientists to believe that a water ocean exists beneath it, which could potentially hold extraterrestrial life.

Nasa is planning a mission to Europa in 2022 that will likely map the surface of the moon, but the mission to find life there might only begin in 2040.

The frozen shell of Europa also poses as difficulty, as the lander would have to drill through as much as 15km of ice to get to the ocean believed to be 100km deep.

"The submersibles we have today would do fine in exploring Europa, the only problem is getting them there," he said, as quoted by South Africa's Times Live.

There might be organisms around the ocean's hydrothermal vents, which emit geothermal heated water, such as microbial life or potentially more complex forms. There is a possibility of the existence of intelligent life.

Hand added that he is optimistic that in the near future, the agency will discover life somewhere in the universe.

"I think in the next 20 years we will find out if we are not alone in the universe," he said, adding that finding such life might be as simple as the Mars Rover discovering a fossil on the surface of the planet.

Meanwhile, speaking to BBC 5 Live, a professor of astronomy at the University of Nottingham said we were "pretty close" to finding life outside Earth.

Prof Michael Merrifield said observatories are making unprecedented discoveries about hundreds and potentially thousands of other worlds in our galaxy which could be inhabited.