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00:00The planet Venus is traditionally known as Earth's evil twin. The second world out from our Sun,
00:06it has scorching surface temperatures of up to and beyond 870 degrees Fahrenheit.
00:12The air is thick and choking, and as it consists mostly of carbon dioxide, it's a supremely toxic
00:19atmosphere. And yet, one theory has it that human beings may have originated from this very place.
00:27So, how could that be?
00:31In September 2020, news broke of a groundbreaking study of Venus.
00:35Led by scientists from Cardiff University in the UK, it found that in the Venusian clouds,
00:40high above the surface of the planet itself, there are traces of phosphine,
00:44a molecule that's one part phosphorus and three parts hydrogen. Back here on Earth,
00:49phosphine is a marker of life, usually found in anaerobic or low-oxygen environments.
00:54The discovery, then, sparks all-new debate about whether there's alien life elsewhere
00:58in the solar system… and whether Venus, Earth's hellish, uncompromising neighbour
01:02so often overlooked when it comes to potential alien homes, could be the place to find it.
01:07Importantly, the team behind the phosphine discovery haven't even begun to claim that
01:11their work should stand as proof that life exists on Venus. In fact, they've openly invited other
01:17scientists, astronomers and researchers to find another explanation for it.
01:21And we are dealing with a pretty tiny signature here, with only about ten to
01:25twenty phosphine molecules per billion. Still, even at such a low concentration,
01:30and even discovered where it has been, about thirty miles above the surface of Venus,
01:34analysts all over the world are scratching their heads as to how it got there.
01:38And the presence of life, either now or in the past, remains a very active line of inquiry.
01:43The idea that life could've existed on Venus in the distant past isn't a totally new one.
01:47While Mars usually steals most of the headlines when it comes to planetary exploration,
01:52we've been quietly looking the other way to study Venus over recent decades, too…
01:56and the theories about the second-closest planet to the sun are mounting up.
02:00In terms of the here and now, Venus doesn't have much going for it. Extreme temperatures
02:05more than 450 degrees Celsius, crushing pressure and a 96% carbon dioxide atmosphere mean that it
02:11ranks as one of the least hospitable places we've ever tried to get close to. And we have tried.
02:17In the 1970s and 80s, various Soviet Union probes attempted the perilous descent onto Venus,
02:23with varying success. But even those that did actually land on the surface
02:27only lasted for a short while before they were destroyed, with the still-record time on the
02:31ground set by the Venera 13 probe in 1982, which endured 127 minutes before it succumbed.
02:38NASA has also landed on Venus with the Pioneer Project in 1978, but most of everything else
02:44we've tried with the planet has been limited to orbiters and flybys. The Soviet spacecrafts
02:48Venera 15 and 16 orbited in the mid-80s, relaying back vital information to suggest a total lack of
02:54plate tectonics on the planet. Then, NASA's Magellan mission, in the early 90s, more extensively
03:00mapped Venus, helping us to determine that its surface was relatively young, probably between
03:05500 million and 800 million years old. By now, we were forming a picture of Venus as a dead planet,
03:11but also as somewhere that might've once been more alive. In more recent years, that picture
03:15has become more detailed. The Venus Express was a European Space Agency mission operating for
03:21more than nine years, between late 2005 and early 2015. Again, it studied Venus from afar,
03:27but this time with something else in mind, as well… climate change.
03:31As we've come to realise that Venus, as we know it, has been choked with carbon dioxide,
03:36showing a runaway greenhouse effect, soaring temperature extremes and generally nightmarish
03:40conditions, there's an argument that it is what Earth could become if global warming continues
03:44here unchecked. A key finding of the Venus Express mission, however, was further reported evidence of
03:50past oceans on the planet. Today, it's a scorched and poisonous place, but long ago it really might
03:55not have been. As the excitement surrounding Venus grows, then, there is a dedicated mission
04:00moving around the planet as we speak, with the JAXA probe, Akatsuki, in orbit since 2015.
04:06So, it's very much a case of watch this space in terms of more news coming from this particular
04:11region of the solar system. Nevertheless, it remains a big leap from suspecting that life
04:15of any kind might exist, or might have at one time existed, on Venus, to saying that human
04:21beings might've lived there before they lived here. And yet, the suggestion has been made before now.
04:26In September 2019, almost exactly one year before the 2020 discovery of phosphine,
04:31a team from NASA's Goddard Institute released details of a study wherein five simulations
04:36showed how Venus might've evolved with different degrees of water coverage.
04:40These sims built on what was by 2019 are fairly solid belief that Venus did once host oceans,
04:46only it imagined that those oceans could've continued to thrive. In real life, we know that
04:50they didn't. We know that something happened around 700 million years ago to trigger what's
04:55been called an outgassing of CO2, and thus the runaway greenhouse effect we know has now taken
05:00hold. Take that outgassing event away, though, and all five of the Goddard Institute's simulations
05:06suggested that Venus would've been able to maintain safe, suitable temperatures for life to exist.
05:11No-one's too sure what caused Venus to become clogged with CO2, but if it hadn't, then it really
05:16might've been like a twin world to Earth… a place very much like it, with only slightly higher
05:21temperatures, on account of its closer proximity to the sun. When scientists and astronomers
05:26analyse far-off star systems today, they often speak of the Venus Zone, meaning a close band
05:31around a star where the planets inside are suspected to be unsuitable for life. But,
05:35if Venus is only so inhospitable because of a chance event, the outgassing that no-one's really
05:40sure on a reason for, then perhaps we shouldn't be so quick to write off Venus Zone objects in our
05:45search for alien life. One key aspect when analysing an alien world is, can it maintain
05:50liquid water? And, according to the Goddard Institute, if history had played out differently,
05:55then Venus might well have. So, what are the chances that human beings could've evolved there
05:59as they have here? On the one hand, the human species can be seen as simply the result of the
06:04right chemicals and conditions and elements being present at just the right time. Modern humans have
06:09only been on Earth for 300,000 years or so, although our evolutionary ancestors had been
06:14around for much, much longer before then. Regardless, even 300,000 years is but a blip
06:19in the grand scheme of the universe. And it only represents a very small percentage of the time
06:24that Venus has been around for, which is about 4.5 billion years. If, then, there's an argument
06:29that the conditions on Venus now are what Earth is en route to experiencing, then there could also
06:34be an argument that Venus might've previously hosted the same, or very similar, conditions
06:38as Earth does today. In which case, what's to say that humans wouldn't have developed, too?
06:43Well, there's one main argument against that having happened. It's just so incredibly,
06:47incredibly unlikely. Developments including the 2020 phosphine discovery continue to show that
06:52the prospects of life in general existing elsewhere are high, with the majority scientific
06:57consensus being that there is alien life out there… we just haven't found it yet. Venus has
07:02never really been at the forefront of our search for life because it's so hostile… but that view
07:07is slowly changing. Now, it no longer feels beyond belief that alien life of some type
07:12could've at one time survived there. But carbon-copy human beings? Probably not.
07:17Even if the Venusian conditions were once closer to Earth's, the planet's entire timeline will
07:22have had to have mimicked Earth's almost perfectly… which it can't have done because all of this will
07:26have had to have happened at least a few hundred million years ago, some time before the carbon
07:31dioxide-inducing outgassing that cast the planet into ruin. Just as most theories indicate that
07:36alien life anywhere isn't likely to look all that human, despite what the movies suggest,
07:40if alien life was found on Venus, or found to have existed in Venus' history, there's really
07:45no telling what it would be like. The chances of walking, talking, recognisable humans just so
07:50happening to evolve on the planet next to ours, out of the billions of other planets out there,
07:55are then absurdly low… with or without phosphine molecules being discovered in the Venusian clouds
08:00of today. What do you think? Is there anything we missed? Let us know in the comments, check
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