[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,The Earth is 4.6 billion years old,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,but a human lifetime often lasts\Nfor less than 100 years.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,So why care about\Nthe history of our planet
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,when the distant past seems\Nso inconsequential to everyday life?
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,You see, as far as we can tell,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Earth is the only planet\Nin our solar system
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,known to have sparked life,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and the only system able to provide\Nlife support for human beings.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,So why Earth?
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,We know Earth is unique\Nfor having plate tectonics,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,liquid water on its surface,\Nand an oxygen-rich atmosphere,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,but this has not always been the case,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and we know this because ancient rocks
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,have recorded the pivotal moments\Nin Earth's planetary evolution.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,And one of the best places\Nto observe those ancient rocks
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,is in the Pilbara of Western Australia.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,The rocks here are 3.5 billion years old,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and they contain some of the oldest\Nevidence for life on the planet.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Now, often when we think of early life,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,we might imagine a Stegosaurus,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,or maybe a fish crawling onto land,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,but the early life that I'm talking about
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,is simple microscopic life like bacteria,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and their fossils are often preserved
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,as layered rock structures\Ncalled stromatolites.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,This simple form of life\Nis almost all we see in the fossil record
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,for the first three billion years\Nof life on Earth.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Our species can only be traced\Nback in the fossil record
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,to a few hundred thousand years ago.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,We know from the fossil record,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,bacteria life had grabbed\Na strong foothold
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,by about 3.5 to four billion years ago.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,The rocks older than this\Nhave been either destroyed
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,or highly deformed\Nthrough plate tectonics,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,so what remains a missing\Npiece of the puzzle
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,is exactly when and how\Nlife on Earth began.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,So here again is that ancient\Nvolcanic landscape in the Pilbara.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Little did I know that our research here\Nwould provide another clue
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,to that origin of life puzzle.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,It was on my first field trip here
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,toward the end of a full\Nlong week mapping project
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,that I came across something\Nrather special.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Now, what probably looks like\Na bunch of wrinkly old rocks
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,are actually stromatolites,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and at the center of this mound\Nis a small, peculiar rock
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,about the size of a child's hand.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,It took six months before\Nwe inspected this rock under a microscope.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,When one of my mentors\Nat the time, Malcolm Walter,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,suggested the rock resembled geyserite.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Geyserite is a rock type that only forms
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,in and around the edges\Nof hot spring pools.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Now in order for you to understand\Nthe significance of geyserite,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,I need to take you back\Na couple of centuries.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,In 1871, in a letter\Nto his friend Joseph Hooker,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Charles Darwin suggested,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,"What if life started\Nin some warm little pond
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,with all sort of chemicals
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,still ready to undergo
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,more complex changes?"
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Well, we know of warm little ponds.\NWe call them hot springs.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,In these environments you have hot water
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,dissolving minerals\Nfrom the underlying rocks.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,This solution mixes with organic compounds
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and results in a kind of chemical factory,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,which researchers have shown\Ncan manufacture simple cellular structures
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,that are the first steps toward life.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,But a hundred years after Darwin's letter,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,deep sea hydrothermal vents, or hot vents,\Nwere discovered in the ocean,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and these are also chemical factories.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,This one is located along\Nthe Tonga volcanic arc,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,1,100 meters below sea level\Nin the Pacific Ocean.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,The black smoke that you see billowing\Nout of these chimney-like structures
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,is also mineral-rich fluid,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,which is being fed off by bacteria.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,And since the discovery\Nof these deep-sea vents,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,the favored scenario for an origin of life
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,has been in the ocean.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,And this is for good reason:
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,deep sea vents are well known\Nin the ancient rock record,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and it's thought that the early Earth
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,had a global ocean\Nand very little land surface.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,So the probability that deep sea vents\Nwere abundant on the very early Earth
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,fits well with an origin of life
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,in the ocean.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,However, our research in the Pilbara
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,provides and supports\Nan alternative perspective.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,After three years,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,finally we were able to show that in fact\Nour little rock was geyserite.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,So this conclusion suggested\Nnot only did hot springs exist
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,in our 3.5 billion-year-old\Nvolcano in the Pilbara,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,but it pushed back evidence for life
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,living on land in hot springs\Nin the geological record of Earth
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,by three billion years.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,And so, from a geological perspective,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Darwin's warm little pond\Nis a reasonable origin of life candidate.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Of course, it's still debatable\Nhow life began on Earth,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and it probably always will be,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,but it is clear that it's flourished,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,it has diversified,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and it has become ever more complex.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Eventually, it reached\Nthe age of the human,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,a species that has begun\Nto question its own existence
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and the existence of life elsewhere.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Is there a cosmic community\Nwaiting to connect with us,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,or are we all there is?
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,A clue to this puzzle again\Ncomes from the ancient rock record.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,At about 2.5 billion years ago,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,there is evidence that bacteria\Nhad begun to produce oxygen,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,kind of like plants do today.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Geologists refer to\Nthe period that followed
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,as the Great Oxidation Event.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,It is implied from rocks\Ncalled banded iron formations,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,many of which can be observed as\Nhundreds of meter thick packages of rock
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,which are exposed in gorges
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,that carve their way through\Nthe Karijini National Park
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,in Western Australia.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,The arrival of free oxygen allowed\Ntwo major changes to occur on our planet.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,First, it allowed complex life to evolve.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,You see, life needs oxygen\Nto get big and complex.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,And it produced the ozone layer,\Nwhich protects modern life
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,from the harmful effects\Nof the sun's UVB radiation.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,So in an ironic twist, microbial life\Nmade way for complex life
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and in essence relinquished\Nits three billion year reign
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,over the planet.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Today, we humans dig up\Nfossilized complex life
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and burn it for fuel.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,This practice pumps vast amounts\Nof carbon dioxide into the atmosphere,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and like our microbial predecessors,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,we have begun to make\Nsubstantial changes to our planet,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and the effects of those\Nare encompassed by global warming.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Unfortunately, the ironic twist here
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,could see the demise of humanity,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and so maybe the reason\Nwe aren't connecting with life elsewhere,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,intelligent life elsewhere,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,is that once it evolves,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,it extinguishes itself quickly.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,If the rocks could talk,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,I suspect they might say this:
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,life on Earth is precious.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,It is the product of\Nfour or so billion years
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,of a delicate and complex\Nco-evolution between life and Earth,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,of which humans only represent\Nthe very last speck of time.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,You can use this information\Nas a guide or a forecast,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,or an explanation as to why it seems\Nso lonely in this part of the galaxy.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,But use it to gain some perspective
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,about the legacy that you\Nwant to leave behind
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,on the planet that you call home.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Thank you.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,(Applause)