Cosmos shows, basically, four different arks. The first is that of writing. Tyson takes us back to ancient Uruk, humanity's first real city, established about 7,000 years ago. About where As-Samawah is in modern-day Iraq (I hope we all know where Iraq is at this point). Uruk was part of the Sumerian/Babylonian civilization that basically straddled the Tigris and Euphrates Rivers. Using the Euphrates River as a highway, Uruk depended on farming villages surrounding it for food and raw materials for the first urban lifestyle. From Uruk, the world's first bureaucrats managed the agriculture, trade, religion and security for the region.
Uruk's DMV, where you could register your barge and get your oarsman license
Uruk has the great distinction of the being the birthplace of writing, the first "ark" Tyson covers. With writing, a person's thoughts and information could be transported and transferred. Harvests could be counted. Receipts could record where produce went and how much was paid. Rules could be made into laws, that could now be standard throughout an Empire. Kings and their reigns could be listed. Basically, with writing, came the invention of fame.
Uruk could also support religious authorities, one of which was an Akkadian Princess named Enheduanna. Princesses could also be Priestesses at this time, and Enheduanna was appointed Priestess of the moon goddess Nanna. It was a powerful position, and so given to royal women close to the king, which she was. It was also a privileged position. Not needing to actually grow her own food or make her own clothes or home, Enheduanna's main job was to keep religious power close to the throne, and write the world's first documented poetry. She is the world's first known poet, mostly religious hymns and praises, but some autobiographical work. She is long since dead. But we still know her name, where she was from, who she was, who her family was, and what she did. Her life story remains, long after she is gone.
The first Emily Dickinson?
Uruk also produced the world's first hero. Before the Greeks' demigods or Ulysses, and our Kryptonians, there was Gilgamesh. The hero of The Epic of Gilgamesh, he was revered as an ancient king of Uruk and son of a goddess. The Epic of Gilgamesh details his travels, searching for immortality, which he didn't find. But he did find an old wise man named Utnapishtim, who gave Gilgamesh the first Great Flood Story. It's eerily similar to Noah's story, but much older. Given the job by a god to fill a giant wooden boat with animals and his family, Utnapishtim survived a 12-day storm that covered land as far as he could see. Three different birds had to be sent out to determine if there was dry land as the waters receded. Utnapishtim counsels Gilgamesh to abandon the quest for immortality, as that is alone for the gods, so Gilgamesh goes home to face death. But his story lives on, in the wide variety of super-human stories we tell each other today, replicating with tweaks through the millenia.
Every story is a re-boot of Gilgamesh's franchise.
Tyson continues to show another story that continues, with tweaks every generation. It's the story of the molecules that live in each and every cell in every living thing. And have replicated, with minor changes in each copying, through billions of years. It's the DNA in our cells. DNA is basically an alphabet of molecules, that we gave the letters A,C, G, and T. These four letters are repeated in varying sequences throughout two, spiralling strands linked by "rungs" of sugars and phosphates that form the structure's backbone. Basically, DNA's job is to determine how each cell is made in order to do the job the cell will have to do. The instructions for making every cell in our body are encoded in a huge sequence of four-letter words. And the full instructions are stored in almost every single cell. The helix only splits, giving half the sequence to one cell and half to another, in our sex, or germ cells, that will be used during reproduction. This process of DNA (or RNA) creating new, self-replicating cells has been going on for 3.5 billion years. The cells of your body are quite young; but the DNA, and the story of life it tells in those cells has been passed down from eons.
Those eons included tweaks, or copying errors in DNA, which produced the mutations that Natural Selection uses to shape living things for their environment. If we go back through the history of life, we find that the earliest organisms were single-celled creatures that existed to make amino acids and proteins. Where did they come from? How did the inert, non-living matter of Earth, 3.5 billion years ago, transition to carbon-based and replicating? That transition is called abiogenesis, and it's the great mystery of our time. We can, in a lab, recreate the conditions on Earth that existed at the time of the first known living things. And those conditions, recreated, can produce the amino acids we need to form DNA. But how do they form DNA and start a replicating process?
Tyson explores the hypothesis that life originated elsewhere, and was literally carried here through space. And he describes the arks that might have transported it. In 1911, a meteorite fell to Earth near Nakhla, Egypt, which is near Alexandria. The Nakhla Meteorite has the distinction of containing compounds that form in water, indicating that it came from somewhere that had water when the meteorite was first formed and sent into space. In 1975, NASA sent the Viking 1 and Viking 2 probes to Mars, and when they landed in 1976, and began examining the content of Mars' atmosphere and surface, scientists figured out that we had a ton of Mar's materials on Earth, produced by collisions in the Early Solar System between Mars and other space debris. When ancient asteroids with more power collided with early planets, including ours, it produced a debris field that drifted into space, to be pushed and shoved by the newly forming planets' gravitational fields, and would eventually orbit the Sun, until prodded by gravity to land somewhere else. In other words, Mars was dumping its trash on our planet.
This includes the Nakhla Meteorite, which shows that Mars must have had water. The Viking Probes found even more evidence of early water on Mars. More importantly, it showed that materials can be transported from planet to planet, by arks called asteroids. Could life have come to Earth this way? It's possible. Some Earth Microbes can survive in space, even for long periods. Less than ten years ago, NASA sent up a sampling of Earth Microbes to live on the outside of the International Space Station, and found some still alive when they were retrieved and brought back to Earth. These microbes survived the cold, the heat, the lack of any atmosphere, and the intense radiation of space. But, could they survive the eons of space travel between worlds? Maybe, they don't have to.
Planets dump their trash on each other in at least one other way, by the movement of stars and their orbiting planets around their galactic cores. Our sun takes a Galactic Year of 225 million Earth years. As it spins around, it passes through dust and gasses of earlier supernovas, where debris from previous solar systems is making its own, slower, trek around the galactic core. Our Sun's gravitational field could easily shove a piece of galactic debris to one of it's planets. And like our International Space Station, there could be small organisms surviving the radiation, cold, heat, and vacuum of space. Were some of them the Earth's original inhabitants, finding Earth a great place to settle down and evolve? Have Earth's ancient microbes seeded other worlds?
Tyson explores one way Earth has dumped on the rest of the universe: radio waves. In 1946, the US Army managed to bounce a radio wave "ping" off the moon, and hear it echoed back, from Belmar, NJ. They called it "Project Diana". However, radio waves expand, like ripples from a water drop. Which means, that most of the radio transmission went past the moon, into space. As does every other single radio transmission ever. Since the mid-twentieth century. All of our music, our TV shows, and even communications. Radio waves travel at the speed of light, which becomes about 6 trillion miles per year. That is about seventy years, or 420 trillion miles from us. Some have, no doubt, reached planets surrounding other stars. Is anybody listening? We are.
SETI is an acronym for the Search for Extra-Terrestrial Intelligence. It takes a few different forms, but the one we're all familiar with was shown in Contact (a movie based on Carl Sagan and Ann Druyan's book) . Basically, we point a radio antenna towards a star, and listen for any radio transmissions coming from it. And like most radios, all we get is static. Is this really the best way to detect other intelligent life over astronomical distances? What if other intelligent species have moved on from radio waves, using some other means of communicating? What if other intelligent species have short-lived civilizations?
Earth's past is full of dead civilizations. Enheduanna and Gilgamesh's society died out thousands of years ago due to war, over-farming, and a drought that ravaged Eurasia. Ancient societies of the Western Hemisphere were also wiped out by drought and the diseases Europeans brought during the Age of Discovery. 74,000 years ago, the massive, supervolcano Toba erupted and spewed sulfur clouds around the world, creating a five-year winter (no Starks, though). Tools from the areas affected showed that humans survived, but their societies did not. Our own Sun has about another 4-5 billion years before becoming a Red Giant that will, at the very least, make Earth a scorched hell. Planets surrounding a Red Dwarf star are luckier, with Suns that can last trillions of years.
Will it be inhabitants of a Red Dwarf system that establish a new, interplanetary society? Or, will humans survive, as we survived the Toba Volcano, and find a way off Earth before our Sun destroys it? Will we repeat Utnapishtim's story, of traveling through an interstellar flood in an advanced society's version of an ark?
Let's hope so.
Life going on...
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