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  • Are you alone in the Universe?

  • Or, are you connected to anything?

  • First of all, you're part of a group of mammals, that's still very young,

  • but we can make YouTube videos already, and build Large Hadron Colliders.

  • We've also split the atom and invented Pokémon.

  • We stem from an ancient life form, that began living about three and a half billion years ago.

  • We feel like we're in control of this planet, but we aren't really.

  • One little asteroid or one creative virus is really all it would take to kill us off for good.

  • Humanity credits itself with being able to destroy the planet,

  • but even with all our nuclear toys, we would probably just cause a huge mass extinction at best.

  • Maybe we could kill 90% of everything living on this planet.

  • Big deal!

  • A few million years later, life would be back everywhere.

  • Most microscopic life and life below the surface wouldn't even be disturbed that much probably.

  • On a geological time scale, our impact on Earth is kind of laughable.

  • We're actually not that powerful.

  • We live on this tiny wet rock that speeds through space, following a massive ball of burning plasma.

  • One day, this ball of plasma will stop burning and, most likely, kill us in the process.

  • If we survived the death of the Sun, and colonized a galaxy,

  • theoretically, we could survive until the last star in the Universe goes out.

  • After that, life becomes pretty impossible.

  • Okay, so, everything has an end.

  • Where does this leave you as an individual?

  • At one point in your life, for about half an hour, you were only one single cell inside your mother's womb.

  • A creature just 0.1 millimeters in diameter.

  • Today, you consist of about fifty trillion cells.

  • Fifty trillion incredibly complex little biological machines,

  • that are much bigger and more complex than the average bacteria.

  • They operate by the laws of physics and chemistry,

  • and use micro-machines to build proteins, make energy usable,

  • devour foods, transport resources, transmit information, or reproduce.

  • They communicate, duplicate, commit suicide, fight off intruders,

  • and fulfill super-specialized duties for the greater good of keeping you alive.. so, you can have babies.

  • But, where is the "you" part in this, if you're made of trillions of little things?

  • The basic information for "you" is stored in the DNA.

  • A molecule that encodes the genetic instructions used in the development and functioning of all known living things.

  • If you were to unravel it, it would be two meters long.

  • If you combined all the little DNA strings in all your cells, you'd get a string so long that it would stretch to Pluto, and back to Earth.

  • That's pretty long.

  • And your DNA is a direct connection to your very first ancestor.

  • Take a second to think about this.

  • In every cell of your body there's a little string of stuff that's been there in various forms for 3.4 billion years.

  • It evolved, it mutated, it duplicated, trillions of times, but it directly connects you to the first living being on this planet.

  • We could say you touched every living being that came before you, with your DNA.

  • But you are more than your DNA.

  • Your body is made of seven octillion atoms.

  • That's seven billion, billion, billions.

  • Roughly 93% of the mass of the human body is made up of just three elements.

  • Oxygen, carbon, and hydrogen.

  • Oxygen and hydrogen are predominately found in water,

  • which makes up about 60% of the body by weight.

  • Carbon is maybe the most important element for life.

  • It can easily bond with other atoms, which allows for the building of long, complex chains of molecules,

  • which make up the solid part of "you".

  • The remaining 7% is a tour of the periodic table of elements.

  • Nitrogen, calcium, phosphorus, potassium, sulfur, sodium,

  • chlorine, magnesium, iron, fluorine, zinc, copper, iodine,

  • selenium, chromium, manganese, molybdenum, cobalt, lithium, strontium,

  • aluminium, silicon, lead, vanadium, arsenic and bromine.

  • Uh!

  • By the way, this also means you're about 0.5% metal. No matter what your favorite music is.

  • Anyway, these elements, perform various functions, like: enabling oxygen transport,

  • building of bones and cell structures, carrying signals, driving chemical reactions, and a lot more.

  • Your body is in a constant state of transition.

  • Every sixteen days, 75% of "you" has been replaced,

  • because a healthy human exchanges about 100% of their water in that time period.

  • Each year, about 98% of your atoms are replaced by new ones,

  • and every 5 years close to all of the atoms that make up your body weren't there five years ago.

  • So, you could call yourself a temporary collection of atoms.

  • But, were did these atoms come from?

  • In the beginning of the Universe, there were mostly hydrogen and helium atoms.

  • Enormous gas clouds formed, over millennia, and grew, denser and denser,

  • until they collapsed under their own gravity, giving birth to the first stars.

  • In the cores of these stars hydrogen was converted into helium under extreme conditions.

  • After millions of years, the hydrogen became exhausted, and the stars began dying.

  • Under super-extreme conditions, all elements we know today were created a fraction of a second before they died and exploded in supernovas.

  • They shot most of their contents into space, while the cores collapsed and became black holes.

  • All these elements traveled through space for who knows how long,

  • until they arrived at a different cloud, that was slowly forming a new star, our Sun.

  • These elements, that once were the insides of a star, formed planets,

  • and found their way onto Earth, where they enabled life to begin.

  • So we are directly connected to the first stars ever born in the Universe.

  • We are part of the Universe.

  • The idea of being a deeply connected minuscule part of an enormous structure is really mind-blowing.

  • We don't know what all of this means.

  • Or, if it means anything at all.

  • We know that we are made of little parts that connect us to everything in the Universe.

  • To the beginning of everything.

  • And this is kind of a nice thought:

  • You are not alone. You never were.

  • You never will be.

Are you alone in the Universe?

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