Scientists have suggested life on our planet might have originated from biological particles brought to Earth in streams of space dust.
In a paper published in Astrobiology, scientists at the University of Edinburgh suggested that fast-moving flows of interplanetary dust delivered tiny organisms from far-off worlds.
“The proposition that space dust collisions could propel organisms over enormous distances between planets raises some exciting prospects of how life and the atmospheres of planets originated,” said professor Arjun Berera of the University of Edinburgh’s School of Physics and Astronomy.
“The streaming of fast space dust is found throughout planetary systems and could be a common factor in proliferating life.”
In the study the scientists also considered how Earth-based organisms could travel to other planets.
The scientists calculated how powerful flows of space dust – which can move at up to 43.75 miles per second (70km/s) – could collide with particles in our atmospheric system.
Small particles existing at 150km or higher above Earth’s surface could then be knocked beyond the limit of Earth’s gravity by fast-moving space dust and eventually reach other planets.
Some bacteria, plants and small animals called tardigrades are known to be able to survive in space, so it is possible that such organisms – if present in Earth’s upper atmosphere – might collide with space dust and withstand a journey to another planet.
The scientists theory, called Panspermia, was first proposed in 1871, and has since been gaining traction among the scientific community, as astronomers have discovered just how full the universe is with organic compounds.
The Panspermia theory suggests that Mars once had the right conditions for life to form, including water and an atmosphere.
Astronomer and director of the multidisciplinary Columbia Astrobiology Centre at Columbia University, Caleb Scharf, told Business Insider: “We can find pieces of Mars here on Earth and we suspect that there are pieces of Earth on Mars.
“If that material can carry living organisms on it, it’s possible that we are Martian.”