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| People Accepted the Fact of Aliens in the Solar System |
Today we’re witnessing a bit of a "golden age" in terms of active work toward answers. Much of that work stems from the overlapping revolutions in exoplanetary science and solar system exploration, and our ongoing revelations about the sheer diversity and tenacity of life here on Earth. Together these areas of study have given us places to look, phenomena to look for, and increased confidence that we’re quickly approaching the point where our technical prowess may cross the necessary threshold for finding some answers about life elsewhere.
Into that mix goes the search for
extraterrestrial intelligence (SETI); as we’ve become more comfortable with the notion that the technological restructuring and repurposing of the matter is
something we can, and should, be actively looking for. If for no other reason
than our own repurposing of matter, here on Earth, has become ever more vivid
and fraught, and therefore critical to appreciate and modify in aid of
long-term survival. But this search labeled as both SETI and the quest for “technosignatures”,
still faces some daunting challenges – not least the catch-up required after decades
of receiving a less-than-stellar allocation of scientific resources.
What is so fascinating is that in many
respects we have already been here and done all of this before, just not
recently, and not with the same set of tools that we now have to hand.
In western Europe, during the period from
some four hundred years ago until the last century, the question of life beyond the
Earth seems to have been less of ‘if’ and more of ‘what’. Famous scientists
like Christiaan Huygens wrote in his Cosmotheoros of “So
many Suns, so many Earths, and every one of them stocked with so many Herbs,
Trees and Animals…even the little Gentlemen around Jupiter and Saturn…” And
this sense of cosmic plurality wasn’t uncommon. It was in almost all respects
far simpler and more reasonable to assume that the wealth of life on Earth was
simply repeated elsewhere. That is once one lets go of a sense of earthly
uniqueness.
In other words, in many quarters there was
no “are we alone?” question being asked, instead, the debate was already onto
the details of how life elsewhere in the cosmos went about its business.
In the 1700s and 1800s, we had astronomers
like William Herschel or the more amateur Thomas
Dick, not only proposing that our solar system, from the Moon to the outer
planets was overrun with lifeforms (Dick held the record by suggesting that
Saturn’s rings held around 8 trillion individuals) but convincing themselves
that they could see the evidence. Herschel, with his good telescopes, became
convinced that there were forests on the Moon, in the Mare humor,
and speculated that the Sun’s dark spots were actually holes in a glowing hot
atmosphere, beneath which, a cool surface supported large alien beings.
Even though we might question some of their scientific standards, people like Herschel and Dick were indeed following the philosophy of life is everywhere and elevating it to the level of any other observable phenomenon. Herschel was also applying the best scientific instruments he could at the time.
All the way into the 20th century,
prior to the data obtained by the Mariner 4 flyby in 1965, the possibility that
Mars had a more clement surface environment, and therefore life still carried
significant weight. Although there had been extreme claims like Percival
Lowell’s “canals” on Mars in the late 1800s and very early 1900s, astronomers
of the time largely disagreed with these specific interpretations.
Interestingly, that was because they simply couldn’t reproduce the
observations, finding the markings he associated with canals and civilizations
to be largely non-existent (an example of how better data can discount pet
theories). But aside from Lowell’s distractions, the existence of a temperate climate of sorts on Mars was not easy to discount, nor was life on its surface.
For example, Carl Sagan and Paul Swan published a paper just
ahead of Mariner 4’s arrival at Mars in which they wrote:
“The present body of scientific evidence
suggests but does not unambiguously demonstrate, the existence of life on
Mars. In particular, the photometrically observed waves of darkening which
proceed from the vaporizing polar caps through the dark areas of the Martian surface has been interpreted in terms of seasonal biological activity.”
Suffice it to say, this proposal went the way
of many other overly optimistic ideas about finding life on the red planet.
Although it is fascinating how well the periodic darkening phenomenon they
discussed could indeed fit into a picture of a surface biosphere on Mars – and
remains perhaps a rather sobering lesson in overinterpreting limited data.
But the key point is that we have actually
more often than not been of a mindset that life is out there, and could explain
certain cosmic observations. The problem has been that, as data has improved,
and scrutiny has intensified, the presence of life has not revealed itself –
from planetary exploration or from the search for extraterrestrial
intelligence. And because of that, we’ve swung to the other extreme, where the question has gone from "what" all the way back to “if.”
Of course, we have also likely systematically underestimated the challenge across the centuries. Even today it is apparent that the search for structured radio emissions from technological life has thus far only scratched the surface of complex parameter space; a fact beautifully quantified and articulated by Jason Wright and colleagues in 2018, as being much like looking in a hot tub of water to draw conclusions about the contents of Earth’s oceans.
In that sense, perhaps the more fundamental
question is whether or not we are, this time, technologically equipped to crack
the puzzle once and for all. There is little doubt that our capacity to sense
the most ethereal, fleeting phenomena in the cosmos is at an all-time high. But
there seems to be a fine line between acknowledging that exciting possibility
and falling prey to the kind of hubris that some of our precursors fell prey
to. Naturally, we say, this is the most special time in human
existence, if we can only expand our minds and our efforts then all may be
revealed!
Of course, none of us can know for sure
which way this will all go. We might do better being very explicit about the
uncertainty inherent in all of this because it’s actually incredibly exciting
to have to face the unknown, and unknowable. What we shouldn’t do is allow the
unpredictable nature of this particular pendulum, swinging between
possibilities, to dissuade us from trying.
The source: Scientific American
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