Space dust already on Earth could hold proof of alien life • The Register

If we wish to discover proof for alien life we needn’t hold in search of chemical compounds in exoplanet atmospheres or distant radio indicators, says a Japanese astronomer. As a substitute, we ought to be learning the 1000’s of micrometer-sized bits of interstellar mud that hit Earth yearly.
College of Tokyo Professor Tomonori Totani proposed the brand new strategy in a paper wherein he suggests bits of house mud might include the stays of single-celled organisms or different chemical proof of life.
This mud would, in fact, must make it via the inhospitable gauntlet of its personal photo voltaic system and thousands and thousands of years of journey via the void of house with out being intercepted first. Regardless of the extremely low probability that items of mud ejected from an exoplanet thousands and thousands of years in the past really make it to Earth, Totani believes round 100,000 items of mud price a glance land on our planet yearly.

“Given there are various unknowns concerned, this estimate could possibly be too excessive or too low, however the means to discover it exist already so it looks as if a worthwhile pursuit,” Totani mentioned. 
Mud might already be right here – however how can we inform it aside from ours?
Loads of house rocks hit Earth annually, forsaking meteorites full of potential scientific discoveries. Sadly, within the strategy of getting into the environment, warmth burns off a whole lot of materials – like traces of organic life.
However the identical rule would not apply to mud particles smaller than 10-100 micrometers, which Totani mentioned are capable of survive atmospheric entry with out producing a lot warmth, which means biosignatures on or within the mud might survive the journey.

Micrometeorites have been discovered each in snow and ice samples from Antarctica, and deep-sea sediment, Totani mentioned within the paper. He additionally famous, nevertheless, that figuring out interstellar mud would not be simple.
“Extrasolar particles scattered by large planets after which certain to the Photo voltaic System could also be troublesome to differentiate from particles ejected from Earth, even when they include biosignatures,” Totani mentioned within the paper. “Looking for particles with origins outdoors the photo voltaic system is like in search of grains of sand which have fallen into the desert,” he added. 

To catch these particles, Totani suggests attempting to take action in house, as an alternative of ready for them to fall to Earth, by utilizing materials like aerogel, a super-lightweight foam constructed from silica that is 95 % air. NASA has already utilized aerogel to such a function, the truth is: Throughout the Stardust mission within the early 2000s, aerogel was used to catch bits of mud coming off a comet in a fashion just like what Totani proposes. 
Why have a look at mud after we’ve bought these cool telescopes?
With all of the unknowns, and Totani’s admission that “extra quantitative issues” and experiments are wanted to show his thought is possible, the plain query is why we should always even hassle going this route to seek out proof of extraterrestrial life.
We’re already scanning for distant radio signatures, and discovering an identifiable one can be an unambiguous signal that life does exist someplace outdoors Earth. Totani mentioned these observations solely search for clever life, which might be far rarer than vegetation and unintelligent animals, probably leaving tons of life undiscovered. 
As for gathering profiles on the chemical make-up of exoplanet atmospheres, Totani mentioned any candidate biosignature present in that means can be controversial as a result of oxygen and different indicators of life can happen in its absence. 

If – and this can be a fairly massive if – we might discover a technique to type the interstellar mud from the stellar, or if we might construct a mud catcher with an efficient space Totani described as “hopefully akin to Earth … to anticipate one particle detection per yr,” then we’d be capable to discover a mud particle that may include traces of alien life. 
Totani mentioned: “If there are indicators of life in mud grains, not solely might we make sure, however we might additionally discover out quickly.” ®