There has been alot of talkrecently about how we canbest utilizefuture observations from the next generation ofgroundandspace - basedtelescopes in our search for alien spirit . Indeed , as the much - delayedJames Webb Space Telescopeis predicted to characterizeonly five exoplanet atmospheresin its deputation life-time , it is necessary to regain a way to prioritise planets whose data could definitively yield an answer as to whether life live there or not .
To create one such framework , an interdisciplinary team of investigator , led by Arizona State University ( ASU ) , took a closer look at one possible signal of life ( biosignature ): oxygen . Whilst on Earth this accelerator is produce by biological process , on other planets , the teemingness of O could be purely attributed to non - biological processes . In society to tell apart those satellite where a detection of the gas conclusively reveals the mien of life , the team created a “ detectability index . ”
“ The goal of the index is to provide scientist with a tool to pick out the very in effect targets for observance and to maximize the chances of detecting spirit , ” Donald Glaser , lead source of the study put out inThe Astrophysical Journal , said in astatement .
terra firma ’s atomic number 8 detectability index would be in high spirits , as the oxygen in its atmosphere is decidedly down to sprightliness . However , the squad discovered that the index falls dramatically for other Earth - like planet , where weewee accounts for a larger percentage of its mess ; oceans only make up 0.025 percentage of Earth ’s entire mass .
“ It ’s easy to imagine that in another Solar System like ours , an Earth - like satellite could be just 0.2 percent water , ” co - writer Steven Desch of ASU ’s School of Earth and Space Exploration , explain . “ And that would be enough to change the detectability index . Oxygen would not be indicative of life on such planets , even if it were observed . That ’s because an Earth - like planet that was 0.2 percent water — about eight times what Earth has — would have no disclose Continent or country . ”
With no land , it would not be potential for rainfall to weather rock’n’roll and free key nutrients ( such as phosphorous ) that raise the oxygen - producing biosphere ( areas of life ) in the sea . Therefore oxygen fromphotosynthetic lifewould be released at a much lower rate and become undistinguishable to the oxygen produced non - biologically .
So for oxygen to be a reliable biosignature ( ie a sure - fire marker of life ) , the researchers suggest that both body of water and terra firma take to be like a shot detect as well . But with potentially only five exoplanets to dig into , the subject field further recommends that satellite with a urine substance with child than 0.2 pct are Delaware - prioritized , “ at least in searches for life on exoplanets using atmospheric atomic number 8 . ” This will help future mission find fault the best targets to depend for life on .
“ The spying of living on a planet outside our Solar System would change our entire understanding of our position in the population , ” Glaser allege . “ NASA is deep commit in search for life , and it is our hope that this body of work will be used to maximize the chance of detecting life when we calculate for it . ”
