Nasa scientists have discovered a bacteria that could prove that aliens exist.

The microbe can survive in arsenic, an element previously thought too toxic to support human life.

The incredible discovery raises the prospect that life could exist on other planets, which do not have phosphorus in the atmosphere. Phosphorus is believed to be vital for the existence of life.

Thousands of planet-watchers will be disappointed with the discovery, since many had expected the space agency to reveal at a press conference tomorrow evening that it had discovered extra terrestrial life.

Nasa had sparked global alien hysteria by announcing the press conference.

But the truth, it turned out, thanks to The Sun breaking an embargo on the story this morning, was closer to home.

The space agency had said it planned to reveal an “astrobiology finding that will impact the search for evidence of extraterrestrial life” but the information was under embargo until 7pm GMT.

Frenzied speculation ensued.

“Did they find ET?”, asked one headline in the U.S. Another wrote, ‘Has NASA found little green men?’

“It’s still hard for me to understand why people can’t accept that aliens exist… ET is real”, read another on U.S. news website MSNBC.

The scientists discovered the bacteria in Mono Lake in California’s Yosemite National Park.