NASA has admitted that we might find alien life “within the next few decades”.
But in a research paper detailing Nasa’s hunt for extraterrestrial life, a top scientist admitted that “we probably won’t shake hands with aliens”.
Nasa has been hunting for evidence of alien life for years, as part of its SETI program.
There’s been great progress on finding places in the universe that could potentially support life – but actually finding aliens has proved difficult.
However, Nasa researchers Chester E. Harman, of the Nasa Goddard Institute for Space Studies, and Shawn Domagal-Goldman, of the Nasa Goddard Space Flight Centre, are optimistic.
In a report called “Biosignature False Positives” published late last year, they explained that we may be close to a major discovery.
“When trying to detect life on planets orbiting other stars, the direct observation of life (e.g. focusing on a single tree in an alien forest, or seeing an alien, or having the alien shake our hand) is incredibly unlikely,” the report explains.
“They might not even have hands to shake, which would make it impossible, in fact.
“Within the next several decades, however, it may be possible to observe indirect evidence for that life using the so-called biosignatures.”
According to Nasa, we need to hunt for “biosignatures”, which might be far less exciting than actually discovering aliens.
A biosignature is a measurement of observation that requires a biological origin to be explained.
Experts say examples of this on Earth include “dinosaur fossils, empty candy wrappers” and even oxygen.
“Each of these observations provides indirect evidence, of varying strength, for the presence of extant (or extinct) life,” they write.
But the research paper warns over “false positives” that might suggest alien life exists – when actually, it doesn’t at all.
“In our search for life – whether within the earliest part of Earth’s geologic record, on planets within our solar system such as Mars, or especially for extrasolar planets – we must infer the presence of life from its impact on the local or global environment,” the paper explains.
“These ‘bio signatures’, often identified from the known influence of terrestrial organisms on the Earth’s atmosphere and surface, could be misdiagnosed when we apply them to alien worlds.
“The so-called false positives may occur when another process or suite of processes masks or mimics a biosignature.”
Last year, The Sun reported on a separate Nasa paper on the “search for extraterrestrial intelligence”.
In that paper, Professor Silvano P. Colombano suggested that alien life may have already visited us.
He claimed that aliens could look so different from how we expect, and that they may be able to travel huge distances – because we simply can’t comprehend their make-up or technology.
“I simply want to point out the fact that the intelligence we might find and that might choose to find us (if it hasn’t already) might not be at all be produced by carbon based organisms like us,” said Professor Colombano, of Nasa’s Ames Research Centre in California.
“How might that change the above assumptions about interstellar travel? Our typical life-spans would no longer be a limitation (although even these could be dealt with multi-generational missions or suspended animation), and the size of the ‘explorer’ might be that of an extremely tiny super-intelligent entity.”
According to Professor Colombano, scientists are too preoccupied with modern human technology.
This, he says, makes it difficult for us to imagine technology that could have been produced by aliens living on planets older than Earth.
He said “we need to re-visit even our most cherished assumptions”, including that “interstellar travel is impossible or highly unlikely”.
“Considering further that technological development in our civilisation started only about 10,000 years ago and has seen the rise of scientific methodologies only in the past 500 years, we can surmise that we might have a real problem in predicting technological evolution even for the next thousand years, let alone 6million times that amount,” the professor explained.
He added: “Even if the speed of light continues to be an unbreakable barrier, over spans of thousands of years civilisations could probably make interstellar journeys.”
In his paper, titled New Assumptions to Guide SETI Research, Professor Colombano said that recent discoveries of Earth-like planets by the Kepler space telescope offered hope.
He said this should prompt Nasa to “focus our attention on detecting signs of life and technology in specific planetary systems”.
“I feel we need to become more flexible in our assumptions,” he explained.
“The reason is that, while it is still reasonable and conservative to assume that life is most likely to have originated in conditions similar to ours, the vast time differences in potential evolutions render the likelihood of ‘matching’ technologies very slim.”
Professor Colombano is advocating a more “aggressive approach” to the search for alien life.
He also said scientists shouldn’t rule out possible “signals” of alien life, thanks to their own doubtful prejudices.
“In the very large amount of ‘noise’ in UFO reporting there may be ‘signals’ however small, that indicate some phenomena that cannot be explained or denied,” the professor wrote.
“If we adopt a new set of assumptions about what forms of higher intelligence and technology we might find, some of those phenomena might fit specific hypotheses, and we could start some serious enquiry.”
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