How Early Could Life Have Appeared In The Universe?

00:56:12
https://www.youtube.com/watch?v=FpftRRm0jfA

Sintesi

TLDRThe video discusses Gobekli Tepe, one of the oldest known human-made structures, located in Turkey. It emphasizes the importance of the site for understanding the transition to settled human societies and its implications for our knowledge of civilization's origins. The narrative extends to the search for extraterrestrial life, exploring definitions of life, the necessary conditions for its emergence, and Fermi's Paradox, which questions why we have not found evidence of intelligent life. The video concludes by speculating on potential ancient alien civilizations and their legacies that may remain undiscovered across the universe.

Punti di forza

  • 🏞️ Gobekli Tepe is over 10,000 years old and crucial to understanding early human societies.
  • 🔍 The transition from nomadic to settled life is reflected in the site.
  • 🌌 The search for extraterrestrial life raises questions about our understanding of life itself.
  • ⚗️ Life is defined by the ability to store information, catalyze reactions, and self-replicate.
  • 🌠 Fermi's Paradox highlights the silence of the universe regarding extraterrestrial intelligences.
  • 🧬 Experiments like Miller-Urey simulate conditions for life and produced amino acids.
  • ⭐ Stars create the necessary elements for life through nuclear fusion.
  • 💧 Liquid water is essential for the emergence of life as we know it.
  • 🚀 The Hayabusa 2 mission found amino acids in samples from asteroids, linking them to life's building blocks.
  • 🪐 Speculations exist about the remnants of ancient alien civilizations in the universe.

Linea temporale

  • 00:00:00 - 00:05:00

    Portobelli Hill, known for its breathtaking views in Southeastern Turkey, was considered sacred by local Kurds. Initially thought to be a mere vantage point, it became significant when archaeologists unearthed remnants of an ancient village, leading to a realization of its historical importance.

  • 00:05:00 - 00:10:00

    In 1994, Klaus Schmidt, a German archaeologist, excavated Gobekli Tepe, initially mistaking the large stones for grave markers. His discoveries revealed imposing stone structures, including enormous pillars, dating back over 10,000 years, marking it as one of humanity's oldest constructed sites.

  • 00:10:00 - 00:15:00

    Gobekli Tepe was built at the end of the last Ice Age, reflecting a transition to settled lifestyles, though its true purpose remains undetermined, potentially serving as a village or a sacred gathering site before being abandoned, obscured by time.

  • 00:15:00 - 00:20:00

    This site has reshaped our understanding of early human civilization, illustrating that significant social structures predate previously accepted timelines of agriculture and settlement, further deepening the mystery of our origins.

  • 00:20:00 - 00:25:00

    While human evolution is outlined through fossil records, scientists note that we have less than 1% of all historical species documented, indicating the complexity of tracing our past. Exploration of the cosmos raises further questions about life beyond Earth.

  • 00:25:00 - 00:30:00

    As time unfolds, scientific exploration reveals unknowns about our universe. The search extends to monumental artifacts that could exist within interstellar spaces, provoking contemplation about our place in the cosmos and the continuity of life across time.

  • 00:30:00 - 00:35:00

    BetterHelp sponsors discussions on mental well-being, offering easy access to licensed therapists, particularly highlighting the importance of mental health amidst existential queries and human conditions.

  • 00:35:00 - 00:40:00

    A discovery made in Antarctica involved a Martian meteorite, ALH 84001, suggesting ancient life. Although initial findings indicated life structures, subsequent analyses raised doubts, emphasizing difficulties in identifying extraterrestrial life forms and their definitions.

  • 00:40:00 - 00:45:00

    Defining life in scientific terms involves properties such as information storage, catalyzing reactions, and self-replication. Such definitions guide our understanding of what constitutes life and its evolutionary processes.

  • 00:45:00 - 00:50:00

    Current research exemplifies the complexity of classifying life, including considering viruses and exploring early life forms on Earth, presenting a blurred line between living and non-living entities based on various chemical interactions.

  • 00:50:00 - 00:56:12

    The video juxtaposes traditional definitions of life with the burgeoning possibilities of other life forms in unique environments, examining how Earth's early life correlates to emerging theories about potential extraterrestrial existence.

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Video Domande e Risposte

  • What is Gobekli Tepe?

    Gobekli Tepe is an archaeological site located in Southeastern Turkey, considered one of the oldest religious structures built by humans.

  • Why is Gobekli Tepe significant?

    It offers insights into early human civilization, particularly during the transition from nomadic to settled lifestyles.

  • What is Fermi's Paradox?

    Fermi's Paradox questions why, given the immense size and age of the universe, we have not yet detected evidence of extraterrestrial civilizations.

  • What defines life according to the video?

    Life is defined by its ability to store information, catalyze reactions, and self-replicate.

  • How did scientists attempt to replicate the conditions for life?

    Through experiments like Miller-Urey, which simulated early Earth conditions to synthesize amino acids.

  • What role do stars play in the emergence of life?

    Stars are essential for creating the chemical elements necessary for life through nuclear fusion.

  • Can life exist in environments very different from Earth?

    Yes, alternative forms of life may arise in diverse chemical, thermal, and environmental conditions beyond Earth.

  • What potential futures might await intelligent civilizations?

    Civilizations may rise and fall, potentially leaving remnants like probes or structures behind, similar to Gobekli Tepe.

  • What did the Hayabusa 2 mission discover?

    It collected samples from the asteroid Ryugu, which contained amino acids, hinting at the building blocks of life.

  • What are the implications of discovering extraterrestrial life or its remnants?

    Such discoveries could illuminate the origins of life in the universe and our place within it.

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Scorrimento automatico:
  • 00:00:00
    this
  • 00:00:04
    is portobelli Hill
  • 00:00:06
    situated in the Arid Hills of
  • 00:00:08
    Southeastern turkey the mound had long
  • 00:00:10
    been considered Sacred by the local
  • 00:00:12
    Kurdish people on a clear day the view
  • 00:00:15
    from the hill was breathtaking providing
  • 00:00:17
    just enough height to see all the way to
  • 00:00:19
    the distant Horizon irrigated Farms
  • 00:00:22
    filling the surrounding Flatlands
  • 00:00:25
    but by the mid-20th century
  • 00:00:27
    archaeologists had started to realize
  • 00:00:29
    that Potbelly Hill was more than just a
  • 00:00:32
    good vantage point it was clearly the
  • 00:00:35
    remains of an ancient Village abandoned
  • 00:00:38
    long ago and covered in Millennia of
  • 00:00:40
    dirt
  • 00:00:41
    however seeing nothing of exceptional
  • 00:00:43
    importance except what was thought to be
  • 00:00:44
    grave markers they had moved on
  • 00:00:48
    it wasn't until 1994 that another
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    archaeologist the German Klaus Schmidt
  • 00:00:53
    heard of it from the locals
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    Guided by Farmers to the location of the
  • 00:00:58
    Hill he took it upon himself to set
  • 00:01:00
    about his own excavation
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    soon realized that these large
  • 00:01:05
    underground Stones were not grave
  • 00:01:08
    markers but the tops of huge megaliths
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    further work revealed a tremendous
  • 00:01:17
    complex including towering t-shaped
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    pillars long arching paths and
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    concentric circles of imposing stone
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    walls
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    but that was not the biggest surprise
  • 00:01:29
    for once archaeologists were able to
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    date the structure its age astounded
  • 00:01:35
    them
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    the complex was over ten thousand years
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    old
  • 00:01:41
    [Music]
  • 00:01:45
    Potbelly Hill which in Turkish
  • 00:01:48
    translates as quebecally Tepe was
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    discovered to be one of the oldest
  • 00:01:51
    structures ever built by humans
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    constructed right at the end of the last
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    ice age and the transition from hunting
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    and Gathering to a more settled
  • 00:02:00
    lifestyle archaeologists still don't
  • 00:02:03
    know the true purpose of the site it may
  • 00:02:06
    have been a fully functioning Village or
  • 00:02:08
    merely a sacred annual Gathering Place
  • 00:02:10
    either way Gobekli Tepe was vitally
  • 00:02:14
    important to the people who built and
  • 00:02:16
    used it
  • 00:02:17
    but after they abandoned it again for
  • 00:02:20
    his mysterious a reason as to why they
  • 00:02:22
    constructed it in the first place it was
  • 00:02:24
    lost
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    thousands of years of human history
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    hundreds of cultures and dozens of major
  • 00:02:30
    civilizations waxed and waned through
  • 00:02:32
    the area never considering it more than
  • 00:02:35
    an old Hill with some rubbish buried
  • 00:02:37
    beneath the surface
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    Gobekli Tepe serves as a major
  • 00:02:42
    Cornerstone for our modern understanding
  • 00:02:44
    of the development of human civilization
  • 00:02:46
    without it our own past would be that
  • 00:02:49
    much more mysterious
  • 00:02:50
    it was built only ten thousand years ago
  • 00:02:54
    as we push deeper into the past the
  • 00:02:57
    story of our Origins becomes even
  • 00:02:58
    murkier with fossil fragments scattered
  • 00:03:01
    across the globe we can piece together
  • 00:03:03
    the general story of human evolution and
  • 00:03:05
    development beyond that we understand no
  • 00:03:08
    more than the outlines indeed scientists
  • 00:03:11
    estimate that we have fossil evidence
  • 00:03:13
    for less than one percent of all the
  • 00:03:15
    species that have ever lived
  • 00:03:17
    that is just life on Earth
  • 00:03:21
    we have only just begun to explore the
  • 00:03:24
    wider Cosmos without probes and our
  • 00:03:26
    telescopes the vast majority of the
  • 00:03:28
    universe remains completely unknown and
  • 00:03:31
    unmapped what Mysteries await us there
  • 00:03:35
    how far back can we push the origins of
  • 00:03:37
    not just ourselves and life on Earth
  • 00:03:40
    but life in the universe
  • 00:03:43
    like Gobekli Tepe what ancient monuments
  • 00:03:46
    to life await Us in the depths of
  • 00:03:50
    interstellar space
  • 00:03:52
    are we among the first generation
  • 00:03:55
    or the latest
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    in a long line
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    due to the sun's larger space-time
  • 00:04:11
    curvature you would get about 67 seconds
  • 00:04:14
    less per year on its surface than on
  • 00:04:17
    Earth which is disappointing and
  • 00:04:19
    sometimes it feels like we don't have
  • 00:04:21
    enough time even here this video has
  • 00:04:23
    been sponsored by betterhelp and they
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    are the world's largest therapy service
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    have a clue on how to access the right
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    supporting educational content on
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    YouTube
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    the lone dark rocks stood out a blemish
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    on the otherwise perfectly smooth
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    perfectly white ice sheets
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    it sat there for thousands tens of
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    thousands of years undisturbed safe for
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    the rare snowfall
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    and Roberta score
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    could not
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    ignore it
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    a lab manager from NASA's Johnson Space
  • 00:05:54
    Center Roberta had been there in
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    Antarctica spending the nightless hours
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    scouring the vast ice fields of that
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    Frozen continent hunting for rocks
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    exactly like it
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    Antarctica is a surprisingly fertile
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    ground for such fines the Rocks stand
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    out clearly in contrast to the blinding
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    White Ice though at first Roberta's rock
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    found in the Allen Hills Far Western ice
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    field and so named alh 84001 seemed
  • 00:06:23
    unremarkable but in reality it was
  • 00:06:26
    anything but for it turned out to not
  • 00:06:28
    only be a meteorite having fallen from
  • 00:06:31
    space Millennia before but Upon
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    returning it to Johnson's Space Center
  • 00:06:36
    the team discovered that it was no
  • 00:06:38
    ordinary meteorite
  • 00:06:40
    it was a piece
  • 00:06:43
    of Mars
  • 00:06:50
    matching the chemical composition of the
  • 00:06:52
    Martian surface The Rock must have been
  • 00:06:54
    blasted off the red planet millions of
  • 00:06:56
    years before during a Titanic Collision
  • 00:06:59
    then spending eons wandering The
  • 00:07:01
    interplanetary Depths before falling to
  • 00:07:03
    Earth where it had rested undisturbed
  • 00:07:06
    ever since the team sampled and studied
  • 00:07:09
    this Martian Exile then made it
  • 00:07:11
    available to The Wider scientific
  • 00:07:13
    community and so it was nearly a decade
  • 00:07:16
    later when another team led by physicist
  • 00:07:19
    David S McKay made a startling
  • 00:07:21
    announcement
  • 00:07:22
    the unassuming meteorite contained
  • 00:07:25
    microscopic features that could not be
  • 00:07:27
    the work of mere chemical processes
  • 00:07:29
    electron microscopy revealed chain-like
  • 00:07:32
    structures that resembled living
  • 00:07:34
    organisms found on Earth
  • 00:07:37
    this Little Rock contained the
  • 00:07:40
    fossilized evidence of life
  • 00:07:43
    on Mars
  • 00:07:45
    NASA announced the discovery to enormous
  • 00:07:47
    Fanfare with even the then president of
  • 00:07:49
    the United States Bill Clinton giving an
  • 00:07:52
    official statement but after the
  • 00:07:54
    celebrations died down and other
  • 00:07:56
    scientists got a chance to perform their
  • 00:07:58
    own examinations these further studies
  • 00:08:00
    immediately cast the original
  • 00:08:02
    announcement in doubt Martian chemistry
  • 00:08:05
    they said did not have to exactly follow
  • 00:08:07
    Earth chemistry and they could concoct a
  • 00:08:10
    dozen different scenarios to generate
  • 00:08:12
    chain-like features from nothing more
  • 00:08:14
    than interesting combinations and
  • 00:08:16
    reactions of chemicals fascinating
  • 00:08:18
    certainly
  • 00:08:20
    but not alive
  • 00:08:22
    alh 84001 Remains the only physical
  • 00:08:25
    specimen to ever even offer a hope of
  • 00:08:28
    identifying life outside the Earth
  • 00:08:31
    and the debates surrounding the nature
  • 00:08:33
    of its microscopic structures serve as a
  • 00:08:36
    potent lesson
  • 00:08:37
    could we even identify alien life if it
  • 00:08:41
    was staring right at us
  • 00:08:43
    [Music]
  • 00:08:47
    to identify life we must first Define it
  • 00:08:50
    and the scientific literature currently
  • 00:08:52
    contains over 200 different definitions
  • 00:08:54
    that said a very general classification
  • 00:08:57
    scheme is able to Encompass almost all
  • 00:08:59
    definitions
  • 00:09:00
    and that scheme relies on life having
  • 00:09:03
    three distinct properties
  • 00:09:06
    One Life must be able to store
  • 00:09:08
    information whatever the means life must
  • 00:09:11
    encode information about its current
  • 00:09:13
    state it must also store information
  • 00:09:15
    about its own traits and characteristics
  • 00:09:17
    and the information required to generate
  • 00:09:19
    various processes
  • 00:09:22
    Second Life must be able to catalyze
  • 00:09:24
    reactions it must be able to interact
  • 00:09:27
    with the environment that surrounds it
  • 00:09:28
    responding to it and generating
  • 00:09:30
    reactions of its own these reactions
  • 00:09:33
    allow life to acquire store and expend
  • 00:09:35
    energy they allow life to move they
  • 00:09:38
    allow life to react to signals or
  • 00:09:40
    threats and lastly these reactions allow
  • 00:09:43
    life to grow new structures
  • 00:09:46
    and third what separates life from
  • 00:09:49
    non-life is the ability to
  • 00:09:51
    self-replicate
  • 00:09:53
    life must be able to make copies of
  • 00:09:56
    itself and these copies must be as
  • 00:09:58
    faithful as possible to the original
  • 00:10:01
    putting these three things together
  • 00:10:03
    allows life
  • 00:10:05
    to live
  • 00:10:09
    famed physicist Owen Schrodinger was the
  • 00:10:11
    first to identify the fundamental
  • 00:10:13
    principles of life from a physical point
  • 00:10:15
    of view
  • 00:10:16
    correctly hypothesizing that the storing
  • 00:10:18
    utilization and passing of information
  • 00:10:20
    was of Paramount importance the
  • 00:10:23
    information stored in life gives it the
  • 00:10:26
    instructions it needs to catalyze
  • 00:10:27
    reactions and some of those reactions
  • 00:10:30
    include the ability for life to
  • 00:10:31
    replicate itself life can then go on and
  • 00:10:34
    do all the things we normally associate
  • 00:10:36
    with living it can move eat protect
  • 00:10:38
    itself send and receive sensory signals
  • 00:10:41
    and most importantly reproduce
  • 00:10:44
    this complete cycle also allows life to
  • 00:10:47
    be subject to Natural Selection
  • 00:10:49
    pressures from the environment work on
  • 00:10:51
    the information passed from one
  • 00:10:53
    generation to another selecting some
  • 00:10:55
    traits is beneficial for survival and
  • 00:10:57
    disregarding others and that in itself
  • 00:11:00
    offers another definition of life life
  • 00:11:02
    is that which is subject to darwinian
  • 00:11:05
    evolution
  • 00:11:07
    on present-day Earth we can see a clear
  • 00:11:09
    example of this definition
  • 00:11:12
    us
  • 00:11:13
    we are quite literally living it
  • 00:11:16
    we have DNA to store information we have
  • 00:11:19
    our proteins that catalyze reactions and
  • 00:11:22
    we have RNA that acts as a translation
  • 00:11:24
    tool from the information stored in our
  • 00:11:26
    DNA to the production of proteins
  • 00:11:29
    and to complete the loop our DNA can
  • 00:11:32
    issue instructions via RNA to create
  • 00:11:35
    proteins that go on to make copies of
  • 00:11:37
    our DNA passing on our genetic Legacy
  • 00:11:40
    from one generation to another
  • 00:11:42
    it's safe to assume that all life in the
  • 00:11:45
    universe fulfills this basic definition
  • 00:11:47
    if it didn't we would have a very hard
  • 00:11:49
    time identifying it as living to put it
  • 00:11:53
    simply to search for life we must have a
  • 00:11:55
    working definition even if that
  • 00:11:57
    definition isn't as broad as it
  • 00:11:59
    potentially could be
  • 00:12:01
    [Music]
  • 00:12:03
    but even on our own planet and with that
  • 00:12:06
    definition in hand we run into
  • 00:12:08
    interesting edge cases
  • 00:12:11
    a virus is alive they store information
  • 00:12:14
    and engage in reproduction but they
  • 00:12:16
    can't do it alone without a suitable
  • 00:12:18
    host
  • 00:12:19
    and what about abiogenesis the
  • 00:12:22
    appearance of life on the early Earth
  • 00:12:25
    at some point a collection of chemical
  • 00:12:27
    processes went from non-living to living
  • 00:12:29
    and that boundary was probably blurry
  • 00:12:32
    the modern Triad of DNA RNA proteins
  • 00:12:36
    couldn't have possibly existed in the
  • 00:12:38
    first life because if you take one of
  • 00:12:40
    those out the cycle of Life cannot
  • 00:12:42
    complete
  • 00:12:43
    so early life had to be simpler one
  • 00:12:47
    hypothesis states that early life was
  • 00:12:49
    solely composed of strands of RNA these
  • 00:12:52
    earliest forms of life would have been
  • 00:12:53
    completely alien to what we have now in
  • 00:12:56
    the modern world
  • 00:12:57
    some aspects of early life we still find
  • 00:12:59
    in common with our own for example early
  • 00:13:02
    life still used the liquid water as a
  • 00:13:04
    solvent and solvents are critically
  • 00:13:06
    important for our understanding of life
  • 00:13:08
    this is because the life on Earth uses a
  • 00:13:11
    soup of complex molecules to go about
  • 00:13:13
    living storing information catalyzing
  • 00:13:16
    reactions and so on these molecules need
  • 00:13:19
    a place to hang out where they won't get
  • 00:13:20
    instantly destroyed and water is stable
  • 00:13:23
    enough for exactly those purposes plus
  • 00:13:26
    water can bind with many other molecules
  • 00:13:28
    it can dissolve the ones you don't want
  • 00:13:30
    acting as a form of waste management and
  • 00:13:32
    it can be easily blocked allowing you to
  • 00:13:34
    build a membrane so that you always have
  • 00:13:36
    just the right amount near you
  • 00:13:41
    in addition to liquid water early life
  • 00:13:44
    also experienced roughly the same
  • 00:13:46
    temperatures that we do today
  • 00:13:48
    even though the first life may have been
  • 00:13:50
    extremophiles like bacteria that can
  • 00:13:52
    survive in deep sea hydrothermal vents
  • 00:13:55
    that is still within the broad range of
  • 00:13:57
    Earth normal early life didn't arise in
  • 00:14:00
    the depths of interstellar space or on
  • 00:14:02
    the surface of the Sun
  • 00:14:04
    early life also used all the same
  • 00:14:06
    elements that we're familiar with today
  • 00:14:08
    carbon is exceptionally handy as it
  • 00:14:11
    combined easily with itself and many
  • 00:14:13
    other elements allowing it to form large
  • 00:14:15
    strong structures oxygen is great for
  • 00:14:18
    participating in chemical reactions
  • 00:14:20
    which means it can serve as a useful
  • 00:14:21
    tool for storing and later using energy
  • 00:14:24
    phosphorus nitrogen and hydrogen also
  • 00:14:27
    play important roles especially in the
  • 00:14:29
    construction of DNA and RNA
  • 00:14:32
    so perhaps early Earth life would not be
  • 00:14:35
    so alien after all the same solvent the
  • 00:14:39
    same temperatures the same Elemental
  • 00:14:41
    building blocks
  • 00:14:42
    those microscopic Critters however they
  • 00:14:45
    initially emerged would have the same
  • 00:14:47
    basic requirements we do water food and
  • 00:14:51
    energy
  • 00:14:53
    but anything off the Earth is a
  • 00:14:56
    completely different story
  • 00:14:58
    [Music]
  • 00:15:04
    perhaps what happened on our planet is
  • 00:15:06
    generic and almost all forms of life in
  • 00:15:09
    the universe need the same basic
  • 00:15:11
    ingredients water carbon sunlight Etc
  • 00:15:15
    or perhaps not after all we only have
  • 00:15:18
    one data point to go on
  • 00:15:20
    and this was one of the major reasons
  • 00:15:22
    why the Martian meteorite was so
  • 00:15:24
    fascinating early Mars had liquid water
  • 00:15:27
    on its surface and a temperate climate
  • 00:15:29
    but Mars also features chemical and
  • 00:15:31
    geological processes that are unique to
  • 00:15:34
    that planet especially in the billions
  • 00:15:36
    of years after its oceans evaporated
  • 00:15:39
    and so we must be exceptionally careful
  • 00:15:41
    when studying other worlds
  • 00:15:45
    thankfully other places in the solar
  • 00:15:47
    system give us the opportunity to test
  • 00:15:49
    how broad our definitions of life can be
  • 00:15:51
    while still being recognizable many of
  • 00:15:55
    the outer moons in the solar system like
  • 00:15:57
    Enceladus and Europa contain vast oceans
  • 00:16:00
    of liquid water but that liquid water is
  • 00:16:03
    locked under miles and miles of ice
  • 00:16:05
    preventing any sunlight at all from
  • 00:16:07
    reaching it not all life on Earth
  • 00:16:09
    requires sunlight so could life have
  • 00:16:12
    gotten started there in the darkness of
  • 00:16:14
    the oceans could a complex food web
  • 00:16:16
    evolve driven by organic material
  • 00:16:18
    drifting through the icy crusts fed upon
  • 00:16:21
    by microscopic organisms to be swept up
  • 00:16:24
    by whale-like eyeless Giants
  • 00:16:28
    and then there's Titan one of Saturn's
  • 00:16:32
    145 moons the second largest moon in the
  • 00:16:35
    solar system it was discovered by the
  • 00:16:37
    great astronomer Christian highgens in
  • 00:16:39
    1655.
  • 00:16:41
    that world is cloaked by a dense
  • 00:16:43
    atmosphere rich with nitrogen and it is
  • 00:16:46
    the only known World other than Earth to
  • 00:16:49
    support lakes and rivers on its surface
  • 00:16:52
    but at a temperature of minus 180
  • 00:16:54
    degrees Celsius these aren't lakes and
  • 00:16:56
    rivers of water but of liquid
  • 00:16:59
    hydrocarbons like methane
  • 00:17:02
    could methane serve as a solvent for an
  • 00:17:04
    exotic low temperature form of life
  • 00:17:07
    perhaps even multicellular creatures
  • 00:17:09
    relying on achingly slow metabolisms
  • 00:17:12
    could swim in those Seas
  • 00:17:15
    research continues but the only way to
  • 00:17:18
    find out for sure would be to go there
  • 00:17:21
    the immense atmospheres of the outer
  • 00:17:23
    planets may also seem uninhabitable to
  • 00:17:25
    us but no one can be sure what strange
  • 00:17:28
    physics and exotic chemistry play out in
  • 00:17:31
    those depths heat motion complex
  • 00:17:34
    compounds all the ingredients are there
  • 00:17:36
    buried layer after layer in those
  • 00:17:38
    atmospheres
  • 00:17:40
    could creatures that never know the feel
  • 00:17:42
    of the ground or the taste of water
  • 00:17:44
    float majestically in those worlds
  • 00:17:48
    and lastly there are all the forms of
  • 00:17:51
    life that we can Encompass in our
  • 00:17:53
    imaginations
  • 00:17:55
    perhaps somewhere in the universe life
  • 00:17:57
    uses silicon rather than carbon as a
  • 00:17:59
    building block perhaps life doesn't even
  • 00:18:01
    need chemicals to store information or
  • 00:18:04
    make copies of itself strange Quantum
  • 00:18:07
    systems could do the trick or forms of
  • 00:18:09
    matter not known to us yet
  • 00:18:12
    everything
  • 00:18:14
    but to begin our exploration of the
  • 00:18:16
    earliest life that could possibly arise
  • 00:18:18
    in the universe we will start with the
  • 00:18:21
    strictest definition of life that we can
  • 00:18:24
    imagine
  • 00:18:25
    life that looks like the kind on Earth
  • 00:18:29
    that uses water as a solvent in a range
  • 00:18:32
    of habitable temperatures using a set of
  • 00:18:34
    key Elemental building blocks
  • 00:18:45
    [Music]
  • 00:18:47
    in 1952 a graduate student at the
  • 00:18:50
    University of Chicago named Stanley
  • 00:18:52
    Miller developed an experiment to test
  • 00:18:55
    the controversial hypothesis developed
  • 00:18:56
    by his advisor Nobel prize-winning
  • 00:18:58
    chemist Harold Yuri
  • 00:19:01
    the experiment was simple Miller took a
  • 00:19:03
    flask of water and added a mixture of
  • 00:19:05
    methane ammonia and hydrogen he then run
  • 00:19:08
    a spark of electricity through the flask
  • 00:19:12
    first nothing happened but after a day
  • 00:19:14
    the mixture turned faintly pink and
  • 00:19:16
    after a week the flask was filled with a
  • 00:19:19
    deep red liquid
  • 00:19:21
    after adding additional chemicals to
  • 00:19:23
    prevent microbial contamination and to
  • 00:19:25
    stop the reaction Miller used a
  • 00:19:26
    chromatograph to identify what new
  • 00:19:28
    molecules had appeared inside the flask
  • 00:19:31
    the results astounded him
  • 00:19:35
    glycine Alpha alanine Beta alanine
  • 00:19:38
    aspartic acid Alpha and aminobutyric
  • 00:19:41
    acid
  • 00:19:42
    these were amino acids the building
  • 00:19:45
    blocks of RNA and DNA the basic
  • 00:19:48
    chemistry of life itself
  • 00:19:51
    [Music]
  • 00:19:55
    Miller's experiment shook the world
  • 00:19:57
    prior to his work philosophers
  • 00:19:59
    theologians and scientists had only
  • 00:20:02
    vague guesses of how life could have
  • 00:20:04
    Arisen on the early Earth now the
  • 00:20:06
    problem of aviogenesis was planted
  • 00:20:08
    firmly in the scientific domain Miller's
  • 00:20:11
    experiment had shown how a mixture of
  • 00:20:13
    simple common molecules could produce
  • 00:20:15
    the basis for the rich organic chemistry
  • 00:20:18
    of life
  • 00:20:20
    the inputs into the experiment water
  • 00:20:23
    methane ammonia and hydrogen are all
  • 00:20:25
    amongst the most common molecules in the
  • 00:20:27
    universe and are made of carbon oxygen
  • 00:20:30
    hydrogen and nitrogen the outputs were
  • 00:20:33
    amino acids which are much more varied
  • 00:20:36
    and complex Arrangements of those same
  • 00:20:38
    basic elements amino acids play a
  • 00:20:41
    central foundational role in
  • 00:20:43
    Biochemistry our DNA encodes information
  • 00:20:45
    for 20 of them and combinations of amino
  • 00:20:48
    acids give rise to our protein
  • 00:20:50
    structures and all of life on Earth
  • 00:20:53
    the experiment had simulated the
  • 00:20:56
    hypothesized conditions of the early
  • 00:20:57
    Earth a warm mixture of what are known
  • 00:21:00
    as Prebiotic molecules the spark had
  • 00:21:04
    simulated a lightning strike in a
  • 00:21:05
    primordial pool triggering a chemical
  • 00:21:07
    transformation that would one day lead
  • 00:21:10
    to Life as We Know It
  • 00:21:14
    while we still don't understand the path
  • 00:21:16
    that led from the Prebiotic early Earth
  • 00:21:18
    to a world rich with living beings the
  • 00:21:21
    Miller Yuri experiment conclusively
  • 00:21:23
    showed that such transitions are
  • 00:21:25
    entirely possible
  • 00:21:27
    further measurements on sealed vials
  • 00:21:29
    from the original experiment revealed
  • 00:21:31
    that Miller had created even more amino
  • 00:21:34
    acids but without having the capability
  • 00:21:36
    to detect them those new amino acids
  • 00:21:39
    included variations not used by life on
  • 00:21:41
    Earth for whatever reason our planet
  • 00:21:43
    having settled on this group of 20 when
  • 00:21:46
    many more options are available
  • 00:21:49
    the Miller Yuri experiment demonstrates
  • 00:21:51
    one Link in the chain of how to create
  • 00:21:53
    Life as we know it you need to have a
  • 00:21:56
    Prebiotic mixture of elements under the
  • 00:21:58
    right conditions
  • 00:22:00
    and so to find the earliest life could
  • 00:22:02
    arise you have to be able to find the
  • 00:22:05
    right mixture of elements and the right
  • 00:22:07
    conditions
  • 00:22:10
    but where could that be in the universe
  • 00:22:20
    of course one place we can be sure of is
  • 00:22:23
    right here the surface of the Earth a
  • 00:22:25
    planet with an abundance of water and a
  • 00:22:27
    thick but not too thick atmosphere for
  • 00:22:30
    our Earth sits in What's called the
  • 00:22:32
    habitable zone of the sun this is a
  • 00:22:35
    region around a star where the
  • 00:22:36
    temperature is just right closer to a
  • 00:22:39
    star and the intense heat and radiation
  • 00:22:41
    will boil away any water turning it into
  • 00:22:44
    a vapor too far away and that water
  • 00:22:46
    freezes into solid ice every Star has
  • 00:22:50
    its own habitable zone with the location
  • 00:22:52
    and size of that zone depending on the
  • 00:22:54
    nature of the star small dwarf stars
  • 00:22:57
    have habitable zones brushing right up
  • 00:22:59
    against their surfaces giant stars have
  • 00:23:02
    habitable zones reaching hundreds of
  • 00:23:04
    millions of miles away
  • 00:23:06
    the habitable zone of the sun begins
  • 00:23:09
    just within the orbit of Venus and
  • 00:23:11
    extends outwards just past the orbit of
  • 00:23:13
    Mars but of the three worlds within that
  • 00:23:16
    zone only the Earth maintains liquid
  • 00:23:18
    water in the present day and so we can
  • 00:23:21
    conclude from this small example that
  • 00:23:24
    the conditions for Life as We Know It
  • 00:23:25
    are very strict with Venus scientists
  • 00:23:29
    strongly suspect that it once had a
  • 00:23:31
    thinner atmosphere and supported oceans
  • 00:23:33
    on its surface but as the sun aged it
  • 00:23:36
    steadily grew brighter and hotter within
  • 00:23:39
    a few hundred million years the intense
  • 00:23:41
    heat from the Sun triggered a runaway
  • 00:23:43
    greenhouse effect on Venus evaporating
  • 00:23:46
    its oceans and building up a thick
  • 00:23:48
    atmosphere dominated by carbon dioxide
  • 00:23:52
    the conditions on the surface are now so
  • 00:23:54
    hellish that it's hot enough to melt
  • 00:23:57
    lead
  • 00:23:59
    Mars on the other hand was also once
  • 00:24:01
    much warmer had a much thicker
  • 00:24:03
    atmosphere and also had oceans rivers
  • 00:24:05
    lakes and streams
  • 00:24:07
    we see evidence for past water activity
  • 00:24:09
    everywhere we look on the surface today
  • 00:24:12
    but as verdant as Mars once was it was
  • 00:24:15
    also born with a fatal defect
  • 00:24:19
    it was too small
  • 00:24:22
    in less than a billion years it cooled
  • 00:24:25
    off its molten core turning solid
  • 00:24:27
    without a molten core its magnetic field
  • 00:24:30
    shut off without a magnetic field the
  • 00:24:33
    solar wind stripped the atmosphere away
  • 00:24:35
    the planet dried
  • 00:24:37
    and died
  • 00:24:40
    however Universe wide that is relatively
  • 00:24:43
    small scale even entire Galaxies have
  • 00:24:47
    their own habitable zones too close to
  • 00:24:49
    the core of a galaxy too many stars will
  • 00:24:52
    live and die flooding their neighbors
  • 00:24:54
    with deadly radiation and the outskirts
  • 00:24:57
    of a galaxy are too thin with heavier
  • 00:24:59
    elements preventing planets from forming
  • 00:25:01
    in the first place
  • 00:25:02
    [Music]
  • 00:25:04
    but to even have the chance for life to
  • 00:25:06
    appear in the habitable zone of a star
  • 00:25:08
    or Galaxy with liquid water rich with
  • 00:25:10
    Prebiotic organic compounds appearing on
  • 00:25:13
    the surface of a planet near a pleasant
  • 00:25:15
    star you first need organic compounds
  • 00:25:18
    and liquid water
  • 00:25:25
    indeed the origins of Earth's abundant
  • 00:25:28
    oceans remains a mystery certainly the
  • 00:25:30
    Earth formed with a lot of water in the
  • 00:25:32
    first place as it's the most common
  • 00:25:33
    element in the entire universe but most
  • 00:25:36
    of the water did not end up on the
  • 00:25:38
    surface it either got locked up as
  • 00:25:40
    chemical compounds in the mantle indeed
  • 00:25:43
    there's more water in the mantle than
  • 00:25:44
    anywhere else on Earth or evaporated
  • 00:25:46
    while our planet was still Molten
  • 00:25:51
    astronomers believe that comets and
  • 00:25:53
    asteroids are likely played an important
  • 00:25:55
    role in replenishing the water supply of
  • 00:25:57
    the earth
  • 00:25:58
    these small leftover bits of debris from
  • 00:26:01
    the formation of the planets generally
  • 00:26:03
    formed in the outer regions of the solar
  • 00:26:05
    system where water could survive as ice
  • 00:26:09
    then impact after impact on the young
  • 00:26:12
    Planet brought with it a fresh round of
  • 00:26:14
    water which eventually built up to
  • 00:26:16
    generate our oceans but again this
  • 00:26:18
    process had to be just right if the
  • 00:26:21
    Earth suffered too many impacts or too
  • 00:26:23
    large then it would have reheated our
  • 00:26:25
    surface turning it molten again and
  • 00:26:27
    sending us back to the start
  • 00:26:30
    and it's also possible that these early
  • 00:26:32
    impacts brought with them
  • 00:26:34
    something else
  • 00:26:37
    in 2014 the Japanese space agency
  • 00:26:40
    launched the Hayabusa 2 mission a probe
  • 00:26:44
    headed to the asteroid ryugo
  • 00:26:46
    that mission collected a sample from the
  • 00:26:48
    surface of ryugu and returned it to
  • 00:26:50
    Earth for closest study
  • 00:26:53
    back in the laboratory scientists were
  • 00:26:55
    amazed to discover the presence of
  • 00:26:57
    several amino acids in the dust grains
  • 00:26:59
    of the asteroid
  • 00:27:00
    including some that formed the basis of
  • 00:27:03
    Earthly life
  • 00:27:05
    and so it seems that the Miller Yuri
  • 00:27:07
    experiment is just one of many options
  • 00:27:10
    available for the universe to make
  • 00:27:11
    organic compounds and more complex amino
  • 00:27:14
    acids scientists aren't sure how these
  • 00:27:17
    molecules were created on ryugo but it
  • 00:27:20
    likely involved some complex interaction
  • 00:27:22
    with the sun's ultraviolet radiation
  • 00:27:24
    which could have provided the energy
  • 00:27:26
    needed to turn simple compounds into
  • 00:27:28
    amino acids
  • 00:27:30
    considering that ryugu is a Remnant from
  • 00:27:33
    the formation of the solar system and
  • 00:27:35
    has remained untouched for over 4
  • 00:27:36
    billion years the timeline would fit for
  • 00:27:39
    the early arrival of life's building
  • 00:27:41
    blocks to the Earth's surface
  • 00:27:44
    but the presence of amino acids goes
  • 00:27:46
    back even further than rocks in our
  • 00:27:49
    solar system
  • 00:27:50
    [Music]
  • 00:27:54
    in 2003 a team of astronomers found
  • 00:27:57
    evidence for glycine the simplest of the
  • 00:27:59
    amino acids in several giant molecular
  • 00:28:02
    clouds these clouds are the places in
  • 00:28:05
    galaxies where stars and solar systems
  • 00:28:07
    form so it's also possible that amino
  • 00:28:10
    acids could have been carried along with
  • 00:28:11
    the formation of the Earth from the very
  • 00:28:14
    beginning
  • 00:28:15
    astronomers have also spotted a variety
  • 00:28:17
    of organic compounds in giant molecular
  • 00:28:20
    clouds throughout the Galaxy in other
  • 00:28:22
    galaxies and even distant quasars
  • 00:28:27
    these quasars only appear in the young
  • 00:28:30
    universe suggesting that the basic
  • 00:28:32
    chemistry for life has been present for
  • 00:28:35
    a very long time
  • 00:28:38
    but even that is not the true beginning
  • 00:28:42
    all that chemistry has to come
  • 00:28:45
    from somewhere
  • 00:28:47
    [Music]
  • 00:28:52
    molecules assemble themselves from
  • 00:28:54
    elements in a variety of processes
  • 00:28:56
    throughout the Universe and almost all
  • 00:28:58
    the elements on the periodic table come
  • 00:29:00
    from a process known as stellar
  • 00:29:02
    nucleosynthesis
  • 00:29:04
    this process was discovered in 1957 in a
  • 00:29:08
    landmark paper authored by the husband
  • 00:29:09
    and wife team of Jeffrey and Margaret
  • 00:29:11
    Burbidge along with William Fowler and
  • 00:29:14
    Fred Hoyle in their work they provided a
  • 00:29:17
    detailed and complete description of how
  • 00:29:19
    Stars fashion elements
  • 00:29:23
    the key is nuclear fusion our sun is
  • 00:29:27
    currently fusing hydrogen into helium to
  • 00:29:29
    generate heat near the end of its life
  • 00:29:31
    it will turn to fusing helium producing
  • 00:29:34
    carbon and oxygen in the process when it
  • 00:29:37
    dies it will spread these elements out
  • 00:29:39
    where they will join the general mix of
  • 00:29:41
    the interstellar medium stars much
  • 00:29:43
    heavier than the sun are capable of
  • 00:29:44
    fusing carbon and oxygen into potassium
  • 00:29:47
    magnesium and more all the elements up
  • 00:29:50
    to and including iron
  • 00:29:53
    to generate even heavier elements the
  • 00:29:55
    universe has to turn to more energetic
  • 00:29:57
    processes
  • 00:29:58
    supernovae carry enough energy to fuse
  • 00:30:01
    many heavy elements but it turns out
  • 00:30:03
    that merging neutron stars carry just
  • 00:30:05
    the right combination of energy duration
  • 00:30:08
    and sheer number of neutrons to produce
  • 00:30:11
    many more including gold and silver
  • 00:30:15
    and so to generate Life as we know it we
  • 00:30:18
    not only need the right conditions the
  • 00:30:21
    right chemicals water and a temperate
  • 00:30:23
    Planet but most fundamentally
  • 00:30:26
    we need Stars
  • 00:30:29
    multiple generations of stars to be
  • 00:30:31
    exact all fusing elements dying in
  • 00:30:34
    Supernova bursts and merging together to
  • 00:30:36
    fill out the periodic table
  • 00:30:41
    only after a galaxy has generated
  • 00:30:43
    sufficient quantities of the basics like
  • 00:30:46
    carbon and oxygen can water and solid
  • 00:30:49
    rock form providing enough material to
  • 00:30:52
    build planets with the required organic
  • 00:30:54
    chemistry
  • 00:30:55
    but stars have not always been present
  • 00:30:58
    in the universe the Big Bang only
  • 00:31:01
    produced hydrogen helium and the
  • 00:31:03
    scattering of lithium and beryllium and
  • 00:31:06
    there were hundreds of millions of years
  • 00:31:07
    before the first Stars ignited
  • 00:31:10
    so on our journey to find the earliest
  • 00:31:12
    possible moment that life could have
  • 00:31:14
    Arisen we will need to reach back into
  • 00:31:18
    the darkest ages of the universe
  • 00:31:34
    imagine years in the future we finally
  • 00:31:37
    uncover what dark matter really is
  • 00:31:42
    after Decades of effort and struggle it
  • 00:31:45
    turns out to be quite simple the vast
  • 00:31:47
    majority of the mass of our universe is
  • 00:31:49
    revealed to be made of some new particle
  • 00:31:51
    that had previously been unknown to
  • 00:31:53
    physics
  • 00:31:54
    some slight adjustments to the standard
  • 00:31:56
    model and a series of confirmed direct
  • 00:31:58
    detections later the mystery is
  • 00:32:01
    conclusively solved a single particle
  • 00:32:04
    that participates in the gravitational
  • 00:32:05
    interaction and very rarely through the
  • 00:32:08
    weak nuclear force
  • 00:32:10
    and that is it
  • 00:32:12
    Laboratories are shut down proposals for
  • 00:32:15
    New Missions scrapped without a grand
  • 00:32:18
    mystery to ignite passion and curiosity
  • 00:32:20
    funding dries up and astronomers and
  • 00:32:22
    physicists go on to study other Cosmic
  • 00:32:25
    questions
  • 00:32:27
    but a small team of scientists persist
  • 00:32:30
    in their experiments and observations
  • 00:32:32
    unconvinced by the accepted explanation
  • 00:32:34
    while the new standard model explains
  • 00:32:37
    the vast majority of Dark Matter
  • 00:32:39
    phenomena there are still some holes for
  • 00:32:43
    example these new dark matter particles
  • 00:32:45
    can very rarely interact with each other
  • 00:32:47
    annihilating in a burst of light a flash
  • 00:32:50
    of gamma-ray radiation for decades we
  • 00:32:54
    had observed an excessive amount of
  • 00:32:55
    gamma rays coming from the center of the
  • 00:32:58
    Milky Way but long assumed it was due to
  • 00:33:00
    some particle physics interactions not
  • 00:33:03
    dark matter
  • 00:33:04
    but this final team working on Dark
  • 00:33:07
    Matter thinks there is more scraping
  • 00:33:11
    together funding they develop a
  • 00:33:12
    high-resolution gamma-ray telescope
  • 00:33:15
    aiming squarely at the center of the
  • 00:33:17
    Milky Way the gamma-ray signal is there
  • 00:33:21
    just as expected a product of the Dark
  • 00:33:23
    Matter particles annihilating
  • 00:33:26
    but the more the researchers study the
  • 00:33:28
    signal the more questions they have
  • 00:33:31
    for the signal isn't perfectly steady
  • 00:33:33
    but is constantly changing ever so
  • 00:33:36
    slightly
  • 00:33:37
    the scientists dream up and discard a
  • 00:33:40
    dozen theories to explain the variation
  • 00:33:43
    nothing works after years of study the
  • 00:33:47
    funding runs out the team disbands
  • 00:33:49
    frustrated at their lack of progress
  • 00:33:53
    [Music]
  • 00:33:56
    but years later on a sleepless night one
  • 00:33:59
    of the former graduate students in the
  • 00:34:01
    group pulls up the old data
  • 00:34:04
    acting on a hunch she processes the
  • 00:34:06
    signal variations in a slightly
  • 00:34:08
    different way
  • 00:34:10
    and then she sees it
  • 00:34:14
    every few seconds the gamma-ray signal
  • 00:34:16
    changes in intensity by a precise amount
  • 00:34:19
    sometimes the signal increases in
  • 00:34:22
    intensity and sometimes it drops the
  • 00:34:25
    time between shifts however never
  • 00:34:28
    changes and the up down pattern never
  • 00:34:30
    repeats except after over a month has
  • 00:34:33
    passed
  • 00:34:34
    then the same Rhythm appears again and
  • 00:34:37
    again
  • 00:34:38
    and again
  • 00:34:39
    marking an increase in intensity is a
  • 00:34:42
    one and a decrease in intensity as a
  • 00:34:44
    zero the former student begins
  • 00:34:47
    scribbling on a nearby piece of scrap
  • 00:34:49
    paper
  • 00:34:50
    [Music]
  • 00:34:52
    one one zero zero zero one one one
  • 00:35:00
    zero zero zero zero one one zero zero
  • 00:35:13
    our quest to find the earliest possible
  • 00:35:15
    appearance of life in the universe has
  • 00:35:17
    taken us to the breaking of the cosmic
  • 00:35:19
    Dawn
  • 00:35:20
    and the birth of the first Stars
  • 00:35:25
    those first Stars fused only hydrogen
  • 00:35:28
    and could have been as large as hundreds
  • 00:35:30
    or thousands of suns they were born they
  • 00:35:33
    lived Furious but brief lives and they
  • 00:35:36
    died beginning the cosmic recycling of
  • 00:35:38
    the elements each generation of stars to
  • 00:35:40
    come after adding to the enrichment of
  • 00:35:42
    the interstellar medium eventually after
  • 00:35:45
    an unknown number of generations a solar
  • 00:35:48
    system could form a star orbited by
  • 00:35:50
    enough Rocky and icy material to Fashion
  • 00:35:53
    planets out of the chaos
  • 00:35:55
    [Music]
  • 00:36:02
    we know that the first Stars didn't
  • 00:36:04
    appear until at least 100 million years
  • 00:36:06
    after the big bang we also know based on
  • 00:36:09
    observations with the James Webb Space
  • 00:36:11
    Telescope and more that galaxies
  • 00:36:13
    appeared to be fully constructed within
  • 00:36:15
    500 million years there was a time
  • 00:36:17
    before that when our universe was 10 to
  • 00:36:20
    15 million years old that the cosmic
  • 00:36:22
    microwave background flooded the
  • 00:36:24
    universe with room temperature radiation
  • 00:36:26
    but that was well before the development
  • 00:36:28
    of rocky planets or even water and so
  • 00:36:31
    while we don't yet have a precise answer
  • 00:36:33
    we do have limits
  • 00:36:35
    the first possibility for Life as We
  • 00:36:37
    Know It swimming in liquid water oceans
  • 00:36:39
    on a rocky planet orbiting a Placid star
  • 00:36:42
    would have occurred somewhere between
  • 00:36:44
    100 and 500 million years after the big
  • 00:36:47
    bang our own solar system formed some 9
  • 00:36:50
    billion years later and so it is safe to
  • 00:36:53
    assume the Earth was not the first
  • 00:36:55
    opportunity for our universe to create
  • 00:36:58
    life
  • 00:36:59
    but of course that's only accounting for
  • 00:37:02
    the kind of life that we conclusively
  • 00:37:04
    know of
  • 00:37:05
    not the kinds of life that we can
  • 00:37:08
    imagine
  • 00:37:11
    [Music]
  • 00:37:13
    let's return to our simple definition of
  • 00:37:16
    life that which is subject to darwinian
  • 00:37:18
    evolution
  • 00:37:19
    this requires information storage
  • 00:37:22
    self-replication and the ability to
  • 00:37:24
    interact with the environment life on
  • 00:37:26
    Earth accomplished this with a soup of
  • 00:37:28
    chemicals immersed in water with deep
  • 00:37:30
    sea vents or sunlight providing an ample
  • 00:37:33
    source of energy to drive chemical
  • 00:37:34
    reactions
  • 00:37:36
    and so the earliest life that looks
  • 00:37:38
    similar to this could not exist for at
  • 00:37:39
    least a few hundred million years well
  • 00:37:42
    after a few generations of stars had
  • 00:37:44
    already come and gone but scientists
  • 00:37:46
    have speculated about many Alternative
  • 00:37:49
    forms of biochemistry besides Methane
  • 00:37:52
    biochemists have also proposed ammonia
  • 00:37:55
    hydrogen fluoride hydrogen sulfide and
  • 00:37:57
    silicon dioxide as alternatives to water
  • 00:38:00
    others have proposed that arsenic which
  • 00:38:02
    is deadly to almost all life on Earth
  • 00:38:04
    might be a useful substitute for
  • 00:38:06
    phosphorus on some exotic world or that
  • 00:38:09
    silicon while not as robust and sturdy
  • 00:38:11
    as carbon might provide a suitable
  • 00:38:13
    foundation for complex molecular chains
  • 00:38:16
    that could lead to intricate living
  • 00:38:18
    systems indeed in 2007 physicist Vadim
  • 00:38:22
    and sidovich ran computer simulations of
  • 00:38:24
    molecular interactions and found that
  • 00:38:27
    Dusty grains in interstellar gas clouds
  • 00:38:29
    when suspended in an energetic plasma
  • 00:38:32
    could begin to self-organize and form
  • 00:38:35
    complex shape
  • 00:38:37
    certainly not life itself but the
  • 00:38:39
    Intriguing hint that something like life
  • 00:38:42
    could arise
  • 00:38:44
    though whether it's the surface of a
  • 00:38:46
    planet deep under a crust or miles of
  • 00:38:48
    atmosphere or tucked away in some
  • 00:38:50
    Interstellar gas cloud all these
  • 00:38:52
    Alternatives ultimately require the same
  • 00:38:55
    thing chemistry
  • 00:38:58
    the elements of the periodic table have
  • 00:39:00
    to exist in the first place before they
  • 00:39:02
    can begin mixing together in interesting
  • 00:39:04
    ways that can potentially lead to life
  • 00:39:06
    and so these Alternatives cannot push
  • 00:39:09
    the emergence of the first life in the
  • 00:39:11
    universe back much before the kinds we
  • 00:39:13
    would recognize on Earth
  • 00:39:15
    [Music]
  • 00:39:16
    to go further back we have to get more
  • 00:39:19
    exotic
  • 00:39:23
    [Music]
  • 00:39:27
    in 1973 eminent physicist Frank Drake
  • 00:39:30
    proposed that microscopic structures
  • 00:39:32
    inside neutron stars could meet all the
  • 00:39:35
    conditions for darwinian evolution these
  • 00:39:38
    structures would be bound by the strong
  • 00:39:40
    nuclear force and could form complex
  • 00:39:42
    interacting shapes surrounded by the
  • 00:39:45
    Abundant energy of the neutron star's
  • 00:39:47
    own heat these structures could
  • 00:39:49
    potentially begin the path to
  • 00:39:51
    self-replication but of course to create
  • 00:39:53
    neutron stars the universe first has to
  • 00:39:56
    create Stars
  • 00:39:58
    and so this possibility pushes back the
  • 00:40:01
    potential for life to just after the
  • 00:40:03
    very first generation of stars some 100
  • 00:40:05
    million years after the big bang
  • 00:40:08
    another hypothesis proposed by Louis a
  • 00:40:10
    andradoki and Eugene M chodnovsky of the
  • 00:40:13
    City University of New York states that
  • 00:40:16
    life composed of magnetic monopoles
  • 00:40:18
    connected by cosmic strings could take
  • 00:40:21
    on complex forms however physicists
  • 00:40:24
    continue to debate the very existence of
  • 00:40:26
    magnetic monopoles and cosmic strings
  • 00:40:28
    and this idea requires that these exotic
  • 00:40:30
    compounds exist in a heat bath namely
  • 00:40:32
    that they are embedded inside Stars so
  • 00:40:36
    that still doesn't push the clock back
  • 00:40:37
    any further
  • 00:40:39
    but there is another possibility hidden
  • 00:40:43
    in the Dark Sector of the universe
  • 00:40:47
    all of our understanding of physics from
  • 00:40:50
    the table of elements to the fundamental
  • 00:40:51
    particles comprises less than five
  • 00:40:54
    percent of all the energy and mass in
  • 00:40:57
    the entire universe most of the cosmos
  • 00:40:59
    is of a form unknown to Modern physics
  • 00:41:03
    this unknown is divided into two sectors
  • 00:41:06
    dark matter which makes up the mass of
  • 00:41:09
    most galaxies and dark energy which is
  • 00:41:11
    responsible for the accelerated
  • 00:41:13
    expansion of the universe
  • 00:41:15
    despite this categorization scheme we
  • 00:41:18
    still don't understand the natures of
  • 00:41:20
    dark matter and dark energy
  • 00:41:22
    they could very well be simple a
  • 00:41:25
    particle that interacts with nothing
  • 00:41:26
    except through gravity and a Quantum
  • 00:41:28
    force that pervades space-time
  • 00:41:31
    or they can be more complex
  • 00:41:33
    new forces of nature could allow Dark
  • 00:41:36
    Matter to interact with itself and with
  • 00:41:39
    dark energy there could be multiple
  • 00:41:41
    species of Dark Matter particles
  • 00:41:43
    entirely new interactions could take
  • 00:41:45
    place among these particles allowing
  • 00:41:47
    them to form their own Periodic Table of
  • 00:41:50
    dark elements
  • 00:41:52
    dark atoms dark molecules dark chemistry
  • 00:41:56
    dark life
  • 00:41:58
    a completely alien form of life using
  • 00:42:02
    sources of energy beyond our
  • 00:42:03
    understanding existing in the Hidden
  • 00:42:05
    Shadows of the universe that life could
  • 00:42:09
    be at play right now even in the present
  • 00:42:11
    day Cosmos completely unobservable to us
  • 00:42:15
    and if that kind of dark shadow life is
  • 00:42:18
    possible it could have emerged well
  • 00:42:20
    before the first stars as it had access
  • 00:42:23
    to sources of energy Beyond Simple
  • 00:42:25
    nuclear fusion perhaps Stark life
  • 00:42:28
    appeared while the universe was still in
  • 00:42:30
    its plasma state
  • 00:42:33
    and that is not the end of it
  • 00:42:36
    [Music]
  • 00:42:40
    simply put we do not understand the
  • 00:42:43
    conditions of the extremely early
  • 00:42:46
    universe
  • 00:42:47
    the energies at play when our Cosmos was
  • 00:42:49
    less than a second old are far beyond
  • 00:42:51
    our current level of understanding
  • 00:42:54
    who knows what exotic forces danced in
  • 00:42:57
    the fires of the Big Bang
  • 00:43:00
    who knows what structures and patterns
  • 00:43:02
    emerged something like life could very
  • 00:43:05
    well have Arisen in that Maelstrom
  • 00:43:07
    creating living and maybe even thinking
  • 00:43:10
    Untold Generations passing from one to
  • 00:43:14
    the next unknown and unknowable to us in
  • 00:43:17
    their cold and distant future a legacy
  • 00:43:20
    erased by the inevitable expansion and
  • 00:43:23
    cooling of the cosmos
  • 00:43:25
    emerged and extinct in less than the
  • 00:43:29
    blink of an eye
  • 00:43:33
    but even considering all of these
  • 00:43:35
    remarkable possibilities if ancient life
  • 00:43:37
    did arise
  • 00:43:39
    how could we ever know
  • 00:43:47
    during a pleasant afternoon in the
  • 00:43:49
    summer of 1950 famed particle physics
  • 00:43:52
    Pioneer in Rico Fermi was walking to
  • 00:43:54
    lunch with his colleagues
  • 00:43:57
    as is usually the case when physicists
  • 00:43:59
    take a break from work they started
  • 00:44:01
    speculating in this case around the
  • 00:44:04
    topic of aliens
  • 00:44:06
    after debating back and forth for a
  • 00:44:08
    while on the possibility of
  • 00:44:09
    extraterrestrial life and the likelihood
  • 00:44:11
    of encountering it the conversation
  • 00:44:13
    eventually moved on
  • 00:44:15
    but the question must have dogged in
  • 00:44:17
    Rico because later that lunch apropos of
  • 00:44:20
    nothing he suddenly blurted out
  • 00:44:23
    where is everybody
  • 00:44:27
    the train of logic is simple the Earth
  • 00:44:30
    is not particularly special yes there's
  • 00:44:32
    liquid water on the surface a clement
  • 00:44:34
    environment a rich soup of organic
  • 00:44:36
    materials an abundant and steady supply
  • 00:44:38
    of energy we have no evidence of these
  • 00:44:40
    conditions let alone life arising
  • 00:44:42
    anywhere else in the solar system let
  • 00:44:44
    alone the Galaxy
  • 00:44:46
    and yet the universe is vast
  • 00:44:50
    there are at least a hundred billion
  • 00:44:52
    stars currently alive in the Milky Way
  • 00:44:55
    galaxy there are potentially almost 2
  • 00:44:58
    trillion galaxies within the observable
  • 00:45:00
    volume of the universe and in physics
  • 00:45:02
    nothing happens just once either nature
  • 00:45:05
    forbids it and it never happens or it
  • 00:45:08
    allows it and the universe is large
  • 00:45:10
    enough to accommodate multiple instances
  • 00:45:12
    of even the rarest phenomenon for
  • 00:45:15
    example modern estimates suggest that
  • 00:45:17
    the Milky Way alone hosts around 5
  • 00:45:20
    billion Earth-like planets in the
  • 00:45:21
    habitable zones of sun-like stars
  • 00:45:24
    and that's just one Galaxy
  • 00:45:27
    [Music]
  • 00:45:32
    and so Earth is special and life is rare
  • 00:45:35
    but Earth isn't that special and we have
  • 00:45:37
    no reason to believe life is that rare
  • 00:45:41
    we are just one rocky planet orbiting
  • 00:45:45
    one unremarkable star
  • 00:45:47
    if life happened here then logic
  • 00:45:50
    dictates it must be a somewhat generic
  • 00:45:52
    feature of the universe and so it must
  • 00:45:54
    have happened elsewhere
  • 00:46:00
    and to add to this the universe isn't
  • 00:46:03
    just gigantic
  • 00:46:05
    it is ancient
  • 00:46:08
    Earth-like life could have Arisen as
  • 00:46:10
    early as 100 million years after the big
  • 00:46:12
    bang the cosmos is now almost 400 times
  • 00:46:15
    as old life appeared on the earth as
  • 00:46:17
    soon as the crust cooled and oceans
  • 00:46:19
    formed almost 4 billion years ago and so
  • 00:46:22
    by now almost 14 billion years after the
  • 00:46:25
    big bang and 9 billion years after the
  • 00:46:28
    formation of the Milky Way countless
  • 00:46:30
    alien life forms should have Arisen
  • 00:46:32
    crawled out of their oceans survived
  • 00:46:34
    terrible catastrophes evolved to
  • 00:46:37
    intelligence developed a sophisticated
  • 00:46:39
    civilization and invented the Necessary
  • 00:46:42
    Technology to travel Among the Stars
  • 00:46:45
    even we humans have managed to send a
  • 00:46:48
    spacecraft beyond the bounds of the
  • 00:46:49
    solar system and out into Interstellar
  • 00:46:51
    space and we have been trying for less
  • 00:46:54
    than a century
  • 00:46:57
    Enrico argued that the Galaxy should be
  • 00:46:59
    littered with the debris of alien
  • 00:47:01
    civilizations come and gone there should
  • 00:47:04
    be active probes in the solar system
  • 00:47:06
    remnants of Technology everywhere we
  • 00:47:09
    look logically we should have evolved in
  • 00:47:12
    the plains of Africa with full awareness
  • 00:47:14
    of the aliens watching us even guiding
  • 00:47:16
    us
  • 00:47:17
    and yet
  • 00:47:19
    nothing
  • 00:47:20
    no sign of intelligence let alone life
  • 00:47:23
    anywhere else in the galaxy
  • 00:47:26
    this is fermi's famous paradox
  • 00:47:30
    life should be everywhere but instead we
  • 00:47:33
    are forced to ask
  • 00:47:35
    where is everybody
  • 00:47:38
    [Music]
  • 00:47:46
    answering this Paradox forces us to
  • 00:47:48
    tackle the same challenging question
  • 00:47:50
    again how would we recognize
  • 00:47:52
    extraterrestrial life
  • 00:47:54
    the most exotic forms of life imaginable
  • 00:47:57
    like creatures living in the first
  • 00:47:58
    instant of the Big Bang or within the
  • 00:48:00
    Dark Sector of the universe would likely
  • 00:48:03
    remain elusive to us forever with any
  • 00:48:05
    evidence of their existence hidden from
  • 00:48:07
    even our most clever experiments
  • 00:48:10
    but Earth-like life or even life based
  • 00:48:13
    on exotic chemical combinations that is
  • 00:48:16
    a different story
  • 00:48:18
    one answer is to focus solely on
  • 00:48:20
    intelligent life as the thinking goes
  • 00:48:22
    that while intelligent civilizations May
  • 00:48:24
    tend to be rarer than generic simple
  • 00:48:26
    life they are at least loud as soon as
  • 00:48:30
    humans developed radio technology for
  • 00:48:32
    example we started blasting signals
  • 00:48:34
    around the world and out into space
  • 00:48:39
    this is the backbone of seti the surge
  • 00:48:42
    for extraterrestrial intelligence the
  • 00:48:45
    general seti program searches for radio
  • 00:48:47
    signals produced by artificial means
  • 00:48:49
    radio is especially handy because it's
  • 00:48:52
    easy to generate in large quantities
  • 00:48:54
    with relatively little power and it can
  • 00:48:56
    sail through thousands of light years of
  • 00:48:58
    Interstellar dust clouds without getting
  • 00:49:00
    itself scattered or absorbed
  • 00:49:03
    unfortunately after Decades of scanning
  • 00:49:05
    the radio skies for any signs of
  • 00:49:07
    intelligence we've found nothing
  • 00:49:10
    one possibility of course is that we
  • 00:49:12
    have only barely scratched the possible
  • 00:49:14
    search space after all astronomical
  • 00:49:17
    observations are difficult and expensive
  • 00:49:19
    especially when they are across a broad
  • 00:49:21
    range of frequencies across the entire
  • 00:49:23
    sky and as often as possible
  • 00:49:26
    so we may have simply missed the few
  • 00:49:29
    stray artificial radio signals that have
  • 00:49:31
    washed over the Earth in the past half
  • 00:49:33
    century
  • 00:49:34
    but other seti attempts have also failed
  • 00:49:37
    alternative directions are focused on
  • 00:49:40
    searching for physical artifacts of
  • 00:49:41
    intelligent civilizations like
  • 00:49:43
    alterations of Stellar chemistry as a
  • 00:49:46
    signal to the wider universe or the
  • 00:49:48
    construction of Mega engineering
  • 00:49:50
    projects like Dyson spheres but no known
  • 00:49:53
    Stars show signs of artificial pollution
  • 00:49:56
    and no Dyson spheres appear in our scans
  • 00:49:59
    across the Galaxy and out into the wider
  • 00:50:01
    universe
  • 00:50:03
    besides these searches for intelligence
  • 00:50:05
    hunts for any forms of life have also
  • 00:50:08
    come up empty despite our trying every
  • 00:50:11
    possible angle
  • 00:50:20
    the alien worlds orbiting within the
  • 00:50:22
    habitable zones of Their Stars we've
  • 00:50:24
    studied the light filtering through
  • 00:50:26
    their atmospheres looking for
  • 00:50:27
    biosignatures like excess oxygen and
  • 00:50:29
    methane something that could not
  • 00:50:31
    possibly have a purely chemical origin
  • 00:50:33
    no matter how exotic
  • 00:50:35
    and while many of these searches are
  • 00:50:37
    still nascent the ones we have performed
  • 00:50:40
    have still come up empty
  • 00:50:42
    we found thousands of exoplanets and
  • 00:50:45
    many potentially habitable worlds like
  • 00:50:47
    the trappist-1 system or Proxima B and
  • 00:50:50
    many with thick atmospheres
  • 00:50:53
    and yet in all that work we haven't
  • 00:50:55
    found a single shred of evidence for
  • 00:50:57
    life outside the Earth
  • 00:51:00
    and so where is everybody
  • 00:51:05
    the first possibility to consider is
  • 00:51:07
    that fermi's base assumption is wrong
  • 00:51:09
    that life truly is rare
  • 00:51:13
    the Earth and our conditions being
  • 00:51:15
    special if not entirely unique within
  • 00:51:18
    the Galaxy that you could have a
  • 00:51:19
    thousand a million a billion copies of
  • 00:51:21
    Earth all with the exact same
  • 00:51:23
    temperatures and pressures and soup of
  • 00:51:25
    chemicals and life would only appear on
  • 00:51:27
    one of them
  • 00:51:29
    or perhaps while life may be common
  • 00:51:31
    intelligent life is not
  • 00:51:34
    perhaps there are microbes on almost
  • 00:51:36
    every wet world in the Galaxy but that
  • 00:51:39
    in 14 billion years of cosmic history we
  • 00:51:42
    are the first intelligent civilization
  • 00:51:44
    to arise in the Milky Way to beat the
  • 00:51:47
    astronomical odds stacked against us and
  • 00:51:50
    look into the universe with curious
  • 00:51:52
    minds that we for all intents and
  • 00:51:54
    purposes save for some microscopic
  • 00:51:57
    cousins that we might encounter in our
  • 00:51:59
    Explorations in the distant future
  • 00:52:01
    ah alone
  • 00:52:05
    life could have been right in front of
  • 00:52:07
    our eyes from the start but of a
  • 00:52:09
    chemical form that we cannot yet
  • 00:52:10
    distinguish from non-life perhaps
  • 00:52:12
    creatures really did once crawl through
  • 00:52:15
    that Martian meteorite perhaps the
  • 00:52:17
    buried Seas of the outer moons are alive
  • 00:52:19
    and active but we may not yet realize it
  • 00:52:22
    for what it is
  • 00:52:24
    and of course yet another possibility is
  • 00:52:27
    that both life and intelligence are
  • 00:52:30
    common
  • 00:52:32
    but not for long
  • 00:52:34
    [Music]
  • 00:52:39
    life may gain foothold after foothold on
  • 00:52:42
    countless worlds only to be snuffed out
  • 00:52:45
    just looking at her own geologic history
  • 00:52:48
    illustrates the risks that being alive
  • 00:52:50
    brings how many times was the earth
  • 00:52:53
    almost wiped clean and that even before
  • 00:52:56
    the rise of sentience once intelligence
  • 00:53:00
    arose we developed the capability to
  • 00:53:02
    destroy ourselves relatively quickly but
  • 00:53:05
    perhaps still lack the sophistication to
  • 00:53:08
    assure her own Survival
  • 00:53:10
    proliferation of nuclear weapons and the
  • 00:53:13
    spiraling disaster of climate change may
  • 00:53:15
    not threaten us as a species but it
  • 00:53:17
    could certainly spell Doom for our
  • 00:53:19
    ability to communicate with the wider
  • 00:53:21
    Cosmos could we possibly recover our
  • 00:53:24
    technological might from such a
  • 00:53:25
    catastrophe or would we Linger on for
  • 00:53:28
    Generations returning to the ways of our
  • 00:53:30
    ancient ancestors until some larger
  • 00:53:33
    Calamity consumes us
  • 00:53:36
    but let us put that to one side and
  • 00:53:39
    imagine we prevail
  • 00:53:41
    perhaps we do spread throughout the
  • 00:53:43
    solar system and even the local Galaxy
  • 00:53:46
    overcoming the vast distances that
  • 00:53:49
    separate the Stars perhaps we endure for
  • 00:53:52
    a million years or more an unimaginable
  • 00:53:54
    amount of time to remain technologically
  • 00:53:57
    sophisticated
  • 00:53:58
    the problem is that is almost nothing on
  • 00:54:02
    a cosmic scale
  • 00:54:05
    the universe is 13.8 billion years old
  • 00:54:09
    our home Galaxy one of trillions
  • 00:54:13
    eventually some limit is reached and we
  • 00:54:16
    simply dwindle away with nothing more
  • 00:54:18
    than empty worlds and dead space probes
  • 00:54:21
    to call our Legacy
  • 00:54:24
    and so maybe we're not alone that in 14
  • 00:54:28
    billion years and among two trillion
  • 00:54:30
    galaxies other intelligent species have
  • 00:54:33
    Arisen and even spread but the vast
  • 00:54:36
    expanse of time and space that dominate
  • 00:54:38
    the universe cruelly separates us from
  • 00:54:41
    any meaningful sustained contact our
  • 00:54:44
    loudest radio blasts mere Whispers in
  • 00:54:46
    the background our brightest beacons
  • 00:54:49
    only flickers of dim candlelights
  • 00:55:01
    but perhaps just perhaps our deep
  • 00:55:05
    descendants Generations from now will
  • 00:55:07
    explore our galaxy and find it filled
  • 00:55:10
    with the graveyards of extinct
  • 00:55:11
    civilizations
  • 00:55:13
    what monuments will they find buried
  • 00:55:16
    under miles of dirt on some alien world
  • 00:55:18
    what probes might they encounter in the
  • 00:55:21
    depths of the interstellar void
  • 00:55:23
    such a discovery would answer many
  • 00:55:25
    questions and raise even more it would
  • 00:55:29
    be a clue not just to the origins of
  • 00:55:32
    humanity but to the origins of all life
  • 00:55:34
    in the universe
  • 00:55:37
    what alien Gobekli Tepe sits out there
  • 00:55:41
    waiting for us to find it
  • 00:55:48
    [Music]
  • 00:55:52
    you've been watching the entire history
  • 00:55:54
    of the universe don't forget to like And
  • 00:55:57
    subscribe and leave a comment to tell us
  • 00:55:58
    what you think
  • 00:56:00
    thanks for watching and we'll see you
  • 00:56:03
    next time
  • 00:56:06
    foreign
Tag
  • Gobekli Tepe
  • Ancient Civilization
  • Archaeology
  • Extraterrestrial Life
  • Fermi's Paradox
  • Astrobiology
  • Miller-Urey Experiment
  • Life Definition
  • Human Evolution
  • Cosmos