Space dust could carry traces of alien life forms to Earth, a report has said. In a paper published in the International Journal of Astrobiology, Japanese astronomer Tomonori Totani proposed that grains "ejected from other worlds" should be studied for "potential signs of life."
When an asteroid impacts a planet, or if any other collision occurs, the material is blasted into the atmosphere. This material can continue to travel through space for years. And it may hold clues into what alien life exists out there.
Totani, a professor at the University of Tokyo, said one day humans could use this information to determine what life forms there are.
"The search for life outside our solar system typically means a search for signs of communication, which would indicate intelligent life but precludes any pre-technological life," Totani said in a statement.
"Or the search is for atmospheric signatures that might hint at life, but without direct confirmation, there could always be an explanation that does not require life. However, if there are signs of life in dust grains, not only could we be certain, but we could also find out soon."
This does not mean that all of these pieces will be useful to scientists. Sometimes these grains will be too big, meaning it remains on the planet it came from. Other times, the pieces will be too small to hold any information.
Scientists would have to look for pieces of material that are not too big, or too small. Totani said those about 1 micrometer in size would work.
It is possible that some of these particles are already on Earth. However, determining where they are, or where they came from, would be a challenge.
But of course, there are "large uncertainties" with this proposition, Totani reported.
One important factor to discuss is whether the life clues would remain preserved by the time they reached Earth. The paper reported that they could be damaged on their way to Earth after being blasted from their own planets.
Totani said it is important to investigate and decide on the best biosignatures—features that harbor signs of life—for analyzing.
"My paper explores this idea using available data on the different aspects of this scenario," said Totani. "The distances and times involved can be vast, and both reduce the chance any ejecta containing life signs from another world could even reach us. Add to that the number of phenomena in space that can destroy small objects due to heat or radiation, and the chances get even lower."
Although the idea is feasible, Totani said it will need experimental studies from various experts in order to put it into practice.
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