The moment we prove life exists outside of Earth will be a turning point for mankind.
But how do you imagine this moment would unfold? For example, we theorized for many years that
liquid water could be present on Mars. We found small clues pointing towards its existence.
Today, it is an undeniable fact that water can be found on Mars,
and we also know that in the ancient past it was plentiful. This is how we should imagine
the process of finding life outside of Earth: tiny clues slowly building into a mountain of evidence.
We may have just discovered the first significant clue that we are not alone in the universe!
In 2019 a group of scientists wrote a paper about how we could possibly detect life on
exoplanets using biosignatures. In their paper, they state the most promising chemical to look for
is phosphine. On Earth it is produced by anaerobic ecosystems - basically organisms that don't have
access to oxygen. We do not know of any other process which produces this gas in large amounts.
Therefore, if the gas is detected on an exoplanet there must be significant amounts
for that detection, so it is a strong indicator of biology. In September 2020 a group of astronomers
announced a significant observation of phosphine in the clouds of our nearest neighbouring planet - Venus.
The amount of phosphine they found is almost 1,000 times greater than any known explanation
could account for. Currently the best suggestion we have for this concentration of phosphine
is alien life. The group of astronomers remains hopeful but sceptical and has invited the world
to try to explain this phenomenon. They have looked at all possible known explanations
and disproved them. We will go over some of these in this video.
Many scientists have long speculated that life could exist in the clouds of Venus.
In the upper atmosphere the temperatures and pressures are very similar to that of Earth,
more so than anywhere else in our solar system. Some of the biggest mysteries on Venus are the
dark lines which wrap around the planet. These lines are known to absorb UV light from the Sun
and can be found in this earth-like band of the atmosphere. Could these bands be large colonies
of UV-absorbing organisms? One of the most commonly cited reasons for disproving these organisms
is the high concentration of sulfuric acid in the atmosphere.
If you watched our last video about Venus you'll know that the Soviet Union launched
many missions to the planet and even achieved photographs from the surface! In one of these
missions they discovered elongated particles about 1 micron thick - or the length of a typical bacteria,
floating in the atmosphere. More interesting is these particles may have been covered in
a molecule called S8. This is a ring-like chain of 8 Sulphur atoms which is impenetrable
by sulfuric acid. It could be theorized that these particles are actually bacteria which
have developed a way to coat themselves in S8, and protect themselves from the harsh environment.
This theory is not as outlandish as it seems. Life finds a way. Here on earth we find the
most fascinating examples of life flourishing against all odds and ingenious methods of survival.
We quote Carl Sagan by saying:
"extraordinary claims require extraordinary evidence"
This is one of the reasons why many scientists are still sceptical about these findings.
Although the evidence currently points towards alien life, there may be something else at play
which we do not fully understand.
This could be a special geological or chemical process unique to Venus,
which creates large amounts of phosphine. It may also explain the other anomalies such as the UV
absorbing lines. We don't have a smoking gun that proves we are not alone in the universe
however, this is a good thing. The intrigue and mystery of the planet will ultimately entice us
into further study and exploration. In the 1800s some astronomers believed
they could see canals on the surface of Mars. These canals turned out to be an
artefact from the telescope. Some 200 years later we have learned so much about the surface of Mars
and you can now even view 4k footage directly from the surface. So if the presence of phosphine
combined with the other anomalies is such a strong indicator of biological activities,
then some of you may be thinking the results are wrong or the equipment has malfunctioned.
But, the team scrutinized their methods and even used multiple telescopes to prove repeatability.
Some of you may be thinking that these bacteria hitched a ride on the Russian probes -
yet there wouldn't have been enough time for this amount of phosphine production.
Most people will say there must be a chemical process
that is causing the production of phosphine. The team has reviewed all known production methods
and has ruled them out. They have looked at lightning, meteorites and volcanoes all to no avail.
They cannot figure out what is producing this phosphine. Sceptics will say it is
simply an unknown process unique to Venus, and they could be right. Only time will tell.
So what happens next and what happens if it is proven there are colonies of organisms in
the Venusian atmosphere? Now that this paper has been released to the world, we will see
many proposed explanations, some of which may have been overlooked by the authors and some
which are new. But what would actually happen if we confirmed the existence of microbial life?
It all depends on what the alien life looks like. If this life is extremely similar to earth-based
organisms - utilizing DNA, then it could be quite an underwhelming moment! The simple fact is because of
our proximity to Venus, it's quite possible that organic materials have been exchanged between
the two planets and that the alien life actually originated from Earth. it would be really difficult
to identify the true course of events. It may even be possible that all life on earth originated from
Venus! This is known as the theory of 'panspermia'. It suggests that life is spread throughout the
Universe traveling on comets and other planetary debris. If however this life is completely
different than what we see on Earth then it would be a turning point in the history of humankind.
If the life is not using DNA but some other form of biological reproduction it would all but prove
there has been a second genesis. In other words - life started from nothing, twice, in the same solar
system. This would have huge ramifications and would suggest the universe is literally
teeming with life. Be sure to pay special attention to exactly what type of life is
found, if it is ever found on Venus at all. But for that, I'm afraid we will have to wait. If you want
more ^^^ go and check out our video about 'teegarden-b', one of the most earth-like planets ever found!