1 00:00:00,360 --> 00:00:05,360 Something weird is happening on the planet Venus. We know that Venus is the 2 00:00:05,400 --> 00:00:10,199 most earthlike planet in the Solar System, practically our twin sibling, So in 3 00:00:10,320 --> 00:00:15,039 theory this place should be very familiar to us. But in reality, Venus 4 00:00:15,119 --> 00:00:21,559 is so incomprehensibly strange that we still understand very little about the true nature of 5 00:00:21,600 --> 00:00:25,440 this planet. So are we looking at a vision of the future, the 6 00:00:25,559 --> 00:00:30,879 nightmarish end that awaits all planets, or is Venus a memory of our past, 7 00:00:31,039 --> 00:00:35,439 of a time when the Earth itself was a young, hot volcanic wasteland. 8 00:00:35,560 --> 00:00:40,759 The real secrets lie beneath the surface and above the clouds. This is 9 00:00:40,799 --> 00:00:45,960 the mystery of the planet Venus. We know that there are many similarities between 10 00:00:46,039 --> 00:00:50,159 Venus and the Earth. Both planets are very similar in size and mass, 11 00:00:50,240 --> 00:00:55,280 they have the same rocky composition, They orbit in a relatively similar proximity to 12 00:00:55,320 --> 00:00:59,679 the Sun. But one of these stranger similarities between the two planets is that 13 00:00:59,719 --> 00:01:04,239 both both Venus and the Earth have a young, rejuvenated surface. So what 14 00:01:04,239 --> 00:01:07,200 do we mean by that? Well, if you look at the surface of 15 00:01:07,280 --> 00:01:12,280 Mars Mercury or Earth's moon, you'll find a dense pattern of impact craters. 16 00:01:12,680 --> 00:01:18,719 These are the remnants of multi billion year old asteroid impacts that occurred when the 17 00:01:18,719 --> 00:01:23,799 Solar System was young and still full of rocky leftovers from the formation of planets 18 00:01:23,840 --> 00:01:29,040 and moons. The Earth was not spared from this ancient bombardment. Our surface 19 00:01:29,079 --> 00:01:33,599 would just be as pockmarked as the Moon if not for the continuous rejuvenation of 20 00:01:33,680 --> 00:01:38,040 plate tectonics. The Earth is constantly recycling mass from the surface down into the 21 00:01:38,079 --> 00:01:45,519 mantle and creating new land through volcanic eruptions. The surface of Venus appears to 22 00:01:45,599 --> 00:01:49,799 tell a similar story. The ancient battle scars have been wiped away, leaving 23 00:01:49,840 --> 00:01:56,680 the age old Venusian surface at somewhere between three hundred million and one billion years 24 00:01:56,719 --> 00:02:01,840 old. Except Venus does not have plate tectonics. Instead, it has one 25 00:02:02,000 --> 00:02:07,879 continuous and stagnant lid of rock that surrounds the entire globe. So there's no 26 00:02:08,120 --> 00:02:15,520 easy explanation as to how the entire planet has been resurfaced in such a relatively 27 00:02:15,560 --> 00:02:20,000 small amount of time. Even one billion years on the cosmic scale is fairly 28 00:02:20,080 --> 00:02:23,560 young. You don't need tectonic plates to have volcanic activity, and this is 29 00:02:23,599 --> 00:02:30,199 how we identify that Venus has a stagnant lid. For a surface. On 30 00:02:30,280 --> 00:02:35,240 the Earth, active volcanoes are concentrated along the borders between the tectonic plates, 31 00:02:35,319 --> 00:02:39,479 while on Venus there are thousands of volcanoes spread out across the surface in a 32 00:02:39,560 --> 00:02:46,960 seemingly random distribution. This would indicate that volcanoes simply spring up at any location 33 00:02:46,000 --> 00:02:51,080 where the surface crust is thin, and that their formation is not driven by 34 00:02:51,159 --> 00:02:55,439 physical movement. We have evidence that volcanic activity on Venus continues to the present 35 00:02:55,520 --> 00:03:01,439 day, but this still doesn't fully explain the re surfacing event. Planets with 36 00:03:01,479 --> 00:03:07,400 a stagnant lid will have lower overall volcanic activity than similar planets with tectonic plates. 37 00:03:07,879 --> 00:03:13,520 On the Earth, volcanoes sweep back and forth across the surface over millions 38 00:03:13,520 --> 00:03:16,599 of years, violently reshaping the land as they go, while on a planet 39 00:03:16,680 --> 00:03:22,479 like Mars, volcanoes just sit in the same place for millions of years, 40 00:03:22,520 --> 00:03:29,039 slowly and steadily erupting until they form gigantic mountains like Olympus Monds, the highest 41 00:03:29,039 --> 00:03:32,199 peak in the Solar System. Actually, most of the highest mountains in the 42 00:03:32,199 --> 00:03:38,199 Solar System are located on Mars. Thanks to its stagnant lid and stationary volcanoes. 43 00:03:38,719 --> 00:03:43,319 You would think that a similar thing would happen on Venus, but that's 44 00:03:43,360 --> 00:03:46,599 not been the case. It does have a couple of very tall mountains, 45 00:03:46,759 --> 00:03:50,919 but overall the surface of Venus is much closer to Earth than it is to 46 00:03:51,039 --> 00:03:54,960 Mars, which still leaves us wondering just what the hell happened here. One 47 00:03:54,960 --> 00:04:00,680 of the more interesting theories about the resurfacing of Venus is that it all happened 48 00:04:00,759 --> 00:04:06,360 fairly abruptly in an explosive global cataclysmic event. The idea is that the stagnant 49 00:04:06,400 --> 00:04:12,159 lid of the Venusian surface probably traps in a lot of pressure underneath the surface, 50 00:04:12,439 --> 00:04:15,759 and since Venus is pretty close to the Sun, much closer than Mars, 51 00:04:15,040 --> 00:04:19,519 there is the likelihood that a lot of thermal energy could build up inside 52 00:04:19,560 --> 00:04:25,240 the planet over hundreds of millions of years, and eventually this pressure is going 53 00:04:25,279 --> 00:04:30,120 to reach a point where it can't be contained any longer, releasing as one 54 00:04:30,279 --> 00:04:35,439 catastrophic global volcanic eruption. If Venus did burst like an overfilled balloon at some 55 00:04:35,560 --> 00:04:40,519 point within the past billion years, this would explain everything that we see on 56 00:04:40,560 --> 00:04:44,759 the planet today. After the volcanic pressure release, the planet would cool back 57 00:04:44,800 --> 00:04:51,000 down into a freshly resurfaced globe. Unfortunately, this cataclysmic event permanently erased any 58 00:04:51,079 --> 00:04:56,120 surface evidence of the ancient past on Venus. When we look at the planet 59 00:04:56,120 --> 00:05:00,079 Mars, we know that there was a time when liquid water flowed over the 60 00:05:00,120 --> 00:05:04,079 surface in ancient rivers, lakes, and even oceans. If a relatively small 61 00:05:04,120 --> 00:05:09,360 and cold planet like Mars could support the necessities of life, then it stands 62 00:05:09,399 --> 00:05:13,879 to reason that Venus probably could have done the same. In order to find 63 00:05:13,879 --> 00:05:17,160 the proof, we need to move up. We know that the atmosphere on 64 00:05:17,279 --> 00:05:23,920 Venus is incredibly hostile. We know that is caused by a runaway greenhouse effect, 65 00:05:24,120 --> 00:05:27,279 but we're not entirely sure how it got that way. To begin with, 66 00:05:27,879 --> 00:05:31,040 the surface pressure of Venus is ninety two bar. That means the air 67 00:05:31,160 --> 00:05:35,720 is ninety two times more dense than what we find at the surface of the 68 00:05:35,800 --> 00:05:41,959 Earth. The majority of the Earth's atmosphere is actually composed of nitrogen, one 69 00:05:41,959 --> 00:05:45,879 of the most common elements in the known universe. It accounts for around seventy 70 00:05:45,920 --> 00:05:48,759 eight percent of the air. Oxygen is only around twenty one percent, and 71 00:05:48,800 --> 00:05:54,519 the remaining one percent is mostly an inert noble gas called argone, and zero 72 00:05:54,560 --> 00:06:00,399 point four percent of the Earth's atmosphere is occupied by greenhouse gases like carbon dioxide, 73 00:06:00,600 --> 00:06:04,560 methane, and ozone. Interestingly enough, we know that Venus has around 74 00:06:04,600 --> 00:06:10,000 the same massive nitrogen in the atmosphere as Earth does, and there are even 75 00:06:10,079 --> 00:06:15,439 detectable amounts of molecular oxygen on Venus, but that is all dwarfed by an 76 00:06:15,560 --> 00:06:20,000 unfathomable amount of carbon dioxide. In the Venusian atmosphere, it makes up over 77 00:06:20,160 --> 00:06:25,639 ninety six percent of the total composition and at ninety two bar of density, 78 00:06:25,920 --> 00:06:30,120 that is a lot of carbon dioxide. But where does it all come from? 79 00:06:30,560 --> 00:06:35,040 The Earth manages its own carbon dioxide through a natural cycle. CO two 80 00:06:35,199 --> 00:06:40,720 is absorbed by plants, they die, they fossilize, and then plate tectonics 81 00:06:40,759 --> 00:06:45,319 eventually pull the fossils down deep into the mantle. Then humans came along and 82 00:06:45,360 --> 00:06:48,240 started burning the fossils and putting them straight back into the atmosphere. But that 83 00:06:48,439 --> 00:06:53,360 likely wasn't the case on Venus, and it's also not likely that Venus just 84 00:06:53,480 --> 00:06:57,800 happens to have a massive amount of excess CO two that the Earth does not. 85 00:06:58,480 --> 00:07:01,079 As far as we can tell Venus and the Earth started out as nearly 86 00:07:01,199 --> 00:07:06,560 identical balls of molten rock. The chemical composition should be more or less the 87 00:07:06,600 --> 00:07:13,000 same, meaning that some kind of natural force moved all of the excess carbon 88 00:07:13,040 --> 00:07:16,920 from the inside of the planet to the outside and created the runaway greenhouse effect 89 00:07:17,199 --> 00:07:21,759 that has superheated the planet's surface. This could have happened during the planet wide 90 00:07:21,839 --> 00:07:28,199 cataclysm. That would be a reasonable explanation, meaning that Venus hasn't actually been 91 00:07:28,240 --> 00:07:31,639 what it is now for all that long. Venus is closer to the Sun 92 00:07:31,680 --> 00:07:35,160 than the Earth, but only by around thirty percent, which is not enough 93 00:07:35,160 --> 00:07:40,759 to cause a huge difference in temperature. If you take the excess atmosphere out 94 00:07:40,800 --> 00:07:45,439 of the equation, the average surface temperature of Venus would be around seventy degrees 95 00:07:45,480 --> 00:07:49,040 celsius, which is still too hot, but it's as close to Earth temperature 96 00:07:49,079 --> 00:07:54,240 as we would ever find anywhere in the Solar System. In fact, it's 97 00:07:54,360 --> 00:07:58,600 very likely that there was a time when the atmospheric conditions of Venus were very 98 00:07:58,639 --> 00:08:03,480 similar to the Earth, complete with large amounts of liquid water. Now, 99 00:08:03,519 --> 00:08:07,439 like we said earlier, any geological evidence of flowing water is long gone from 100 00:08:07,480 --> 00:08:13,040 the surface of venus, but the chemical evidence does remain. This comes in 101 00:08:13,079 --> 00:08:16,439 the form of an atom called deuterium. Okay, stick with me here. 102 00:08:16,560 --> 00:08:22,639 Deuterium is an isotope of hydrogen, which basically means that deuterium is a unique 103 00:08:22,800 --> 00:08:28,040 variant of hydrogen that is created by the addition of a neutron inside the core 104 00:08:28,120 --> 00:08:31,720 of the atom. Typical hydrogen only has one proton in the nucleus, while 105 00:08:31,720 --> 00:08:37,879 deuterium has a proton and a neutron inside the nucleus. This gives utium a 106 00:08:37,960 --> 00:08:43,559 heavier atomic weight than hydrogen, and on Earth there is typically one deuterium isotope 107 00:08:43,600 --> 00:08:48,279 for every six thousand, four hundred and twenty atoms of hydrogen. Here's the 108 00:08:48,320 --> 00:08:54,759 payoff. The concentration of deuterium atoms on venus is significantly higher, meaning that 109 00:08:54,840 --> 00:09:00,120 at some point there was a massive amount of hydrogen that dissipated into space and 110 00:09:00,200 --> 00:09:05,399 left behind its heavier isotope variance. This is a smoking gun indicator of a 111 00:09:05,519 --> 00:09:11,200 water boil off event. The water boiled into steam, and the lightest hydrogen 112 00:09:11,240 --> 00:09:15,159 atoms in that steam floated all the way up into the atmosphere and were carried 113 00:09:15,200 --> 00:09:20,399 away by the solar wind, while the heavier atoms remained trapped somewhere in between. 114 00:09:20,879 --> 00:09:24,320 So in this way, when we look at Venus, we are seeing 115 00:09:24,480 --> 00:09:28,600 a likely future for the Earth. We often use Mars as an example of 116 00:09:28,639 --> 00:09:35,080 a dead planet because its geological activity has ground to a halt, the atmosphere 117 00:09:35,080 --> 00:09:39,279 has dissipated, and the average surface temperature has dropped below freezing. But this 118 00:09:39,919 --> 00:09:46,440 is more like a planetary coma death is still to come. We live next 119 00:09:46,480 --> 00:09:52,759 to a gigantic nuclear fusion reactor that is gradually increasing in power right up until 120 00:09:52,759 --> 00:09:56,200 the hydrogen fuel source is depleted. Our Sun won't explode when it dies, 121 00:09:56,399 --> 00:10:01,879 but it will expand outward to become a red giant, which will then eject 122 00:10:01,919 --> 00:10:05,679 its corona and collapse into a white dwarf star surrounded by a nebula of matter 123 00:10:05,919 --> 00:10:11,759 that used to be our solar system. Long story short, In the end, 124 00:10:11,399 --> 00:10:16,799 everything burns. The Earth will not go quietly into that good night anyway, 125 00:10:16,080 --> 00:10:20,519 nihilism aside. Our own planet will gradually, over billions of years, 126 00:10:20,919 --> 00:10:26,039 start to look a lot more like Venus, so we can kind of reverse 127 00:10:26,080 --> 00:10:30,879 engineer the process. It's likely that the water boil off comes first. The 128 00:10:30,960 --> 00:10:33,840 Earth's magnetic field won't last forever. We're not sure if Venus ever had a 129 00:10:33,840 --> 00:10:39,120 magnetosphere or if it just dissipated very early on, which would explain the planet's 130 00:10:39,159 --> 00:10:43,519 short lifespan. Loss of the magnetic field allows the atmosphere to thin, end 131 00:10:43,559 --> 00:10:46,720 hydrogen to escape. Lower atmospheric pressure, combined with a hotter sun, means 132 00:10:46,919 --> 00:10:52,799 that water evaporates much faster and fails to recondense into rain. With no water, 133 00:10:52,080 --> 00:10:56,480 the surface of the Earth gets dry and stiff, which is probably what 134 00:10:56,559 --> 00:11:01,600 brings an end to plate tectonics and causes the outer trust to solidify into a 135 00:11:01,600 --> 00:11:05,039 stagnant lid. Now, thermal energy builds up under the sealed crust of the 136 00:11:05,080 --> 00:11:09,120 Earth until it pops like a balloon, and the entire surface is engulfed in 137 00:11:09,200 --> 00:11:15,200 volcanic activity, spewing massive amounts of heavy carbon gas into the atmosphere to form 138 00:11:15,279 --> 00:11:18,480 dense clouds that cling to the planet. And just like that, the Earth 139 00:11:18,720 --> 00:11:24,000 five billion years in the future would be largely indistinguishable from the planet Venus as 140 00:11:24,039 --> 00:11:30,039 we see it today, unless through reverse engineering Venus' demise, we can somehow 141 00:11:30,120 --> 00:11:33,120 figure out how to stop our planet from sharing the same fate.