00:00You know how it all started 13.8 billion years ago with the Big Bang.
00:05BAM! No, no, wait, I can do better.
00:08Bada-boom! No, it's ... it doesn't matter.
00:11And the universe has not stopped expanding since.
00:14At its beginning, it was entirely composed of gas, mainly helium and hydrogen.
00:20Over billions of years, the gas has spread and cooled.
00:24During this time, galaxies, stars and other mysterious things in space
00:29that we are trying to explore today, have formed under the action of gravitational forces.
00:35And in this Capernaum, about 4.6 billion years ago,
00:39our magnificent planet also appeared.
00:42It all started with a gas and dust disk orbiting around our young sun,
00:47exactly as was the case for the rest of the planets of our solar system.
00:51This disk was made up of gas and dust particles of different sizes.
00:56They rotated around the sun at different speeds
00:59and on orbits that were no more stable than predictable.
01:02They constantly hit each other.
01:05These particles grew from very small grains of dust to become rocks.
01:09And later, larger bodies called planetesimals,
01:13which declined in size from a few kilometers to several hundred kilometers in diameter.
01:18Planetesimals that orbited around the sun within the disk had enough gravitational force
01:23to attract other objects from the neighborhood out of their orbits and collide with them.
01:29As they constantly hit each other, they became bigger and bigger,
01:33reaching diameters of several thousand kilometers.
01:37This is practically the size of Mars and our Moon.
01:40We know all this thanks to meteorites.
01:43They come from different places in our solar system
01:46and bring all kinds of materials to our planet.
01:50They give us something interesting to study and learn about our own system and its formation.
01:56These materials contain very small pieces of dust and rocks called chondra,
02:01which went through chaos and survived the difficult moments that preceded the creation of the planets.
02:07Meteorites also bring pieces of asteroids and planetesimals
02:11left after the end of the planet formation process.
02:14While these objects were forming,
02:16some radioactive elements such as uranium and hafnium were trapped inside the minerals
02:21and became an integral part of them.
02:23This is how scientists were able to determine their age.
02:27But the final phase of formation of our planet, and in general,
02:31all this chaos that shook our solar system may have taken a little longer,
02:36up to about 100 million years more.
02:39It was then that the last great impact occurred
02:42and that the Earth finally reached its current size.
02:45What really happened was that it hit another object almost as big as Mars.
02:51This collision was so powerful that the impact produced enough energy
02:55to vaporize part of the metal and rock, both on Earth and on this planetoid.
03:01And this steam created a disk that surrounded our planet.
03:04It cooled down and regrouped after a while.
03:08And this is how we got the Moon.
03:11Our Moon is the result of the debris of this impact,
03:14which was a combination of hot gas and molten rock.
03:18However, there are other theories about the formation of the Moon.
03:21The fission theory claims that it simply detached itself from the Earth.
03:25The capture theory suggests that the Moon would have formed elsewhere in our solar system.
03:30At some point, while it was walking, it would have gotten so close to the Earth
03:35that it would have ended up being captured by its gravity.
03:38Finally, supporters of the third theory, that of co-formation,
03:42believe that the Moon and the Earth formed simultaneously
03:45from the same protoplanetary disk.
03:48Before the formation of the Moon, the Earth was a very different place.
03:52If you could spend a single day on this Earth without the Moon,
03:55you would be surprised by the cycle of days and nights.
03:59It would not be as regular as it is today
04:01because the Moon helps to stabilize the axis of the Earth.
04:05The days were shorter at the time because the Earth was spinning much faster
04:09before the formation of its satellite.
04:11Its gravitational force slowed the rotation of our planet,
04:15which means that the days got longer.
04:18The rotation of the Earth slows down over time,
04:21but at a really slow pace.
04:23According to some forecasts, within a billion years,
04:26a typical day would last between 25.5 and 31.7 hours.
04:32If 24 hours are not enough for you,
04:34just wait a billion years.
04:38But yes, if you are the kind of person who likes to take his time,
04:41you would certainly have had to hurry at that time.
04:44Although there was not much to do to pass the time,
04:47except sailing on lava, picking up stones
04:50or hoping not to be hit by a meteorite.
04:54Not only was the Earth very likely a lava ball in fusion,
04:58but its landscape was also rocky and sterile.
05:01The Moon at its early stages was also extremely hot.
05:04It was probably similar to a partially melted ball
05:07suspended above our planet.
05:12But if you were patient enough,
05:14maybe you would witness something really cool.
05:17Water coming to our planet for the very first time.
05:20A rain of flaming meteors fell from the sky
05:23and they kept falling on our young Earth.
05:26It may have seemed devastating at first,
05:28but some of these debris probably contained water.
05:32Many believe that asteroids and comets
05:35that hit our planet transported small amounts of water.
05:38But since this rain of meteorites lasted more than 20 million years,
05:42maybe even up to 200 million,
05:45it is not so unlikely that after a while,
05:48puddles of water began to form on the surface.
05:52And when the water evaporated into the atmosphere,
05:55it finally fell again,
05:57forming lakes, rivers, seas and finally oceans.
06:01It was only from this moment that primitive life had the chance to evolve.
06:05The Earth began its transition from an incandescent magma ball
06:09to the world we know today.
06:11Before that, it would have been too difficult for life to exist.
06:15And even if it had happened one way or another,
06:18all these meteor collisions would probably have destroyed it.
06:23You could not survive here either without oxygen bottles.
06:27The Earth had an atmosphere,
06:29but it was not like the one we know today.
06:32Scientists believe that it consisted of water vapor,
06:35methane, ammonia and other gases released by volcanic activity.
06:39Basically, it was far too toxic
06:41because volcanic eruptions occurred all the time.
06:44And the temperatures were much higher.
06:47So that existing at these early stages of our Earth
06:50would not have been a very pleasant experience.
06:53However, there could have been some forms of life at this time.
06:57At its chaotic beginnings,
06:59the Earth was not covered with oceans, trees
07:02or breathtaking landscapes of today,
07:04but with fusion magma.
07:06The oldest form of life we know
07:08are fossils of microorganisms found in hydrothermal chimneys.
07:12And we think they are about 3.4 billion years old.
07:16Scientists estimate that the time when life could have appeared
07:19for the first time on Earth
07:21would be about 4.2 billion years ago, more or less.
07:27Thus, with the right equipment,
07:29you could even observe unicellular organisms,
07:32like bacteria somewhere on the surface of our planet,
07:35and even before the appearance of the Moon.
07:38The gravitational attraction of this on the Earth
07:40creates tides of our oceans,
07:43which means that it probably helped to mix
07:46and circulate the water of the seas,
07:48and perhaps even to shape them.
07:50Tides without the Moon would be much less important,
07:53because it is its attraction that causes the rise and fall of the waters.
07:59The Moon also affects life in the ocean.
08:01Over time, marine animals have evolved
08:04and adapted to the alteration of the water level
08:06caused by lunar gravity.
08:08Even the light of the Moon has a great effect on marine creatures.
08:12Corals, for example,
08:14use the cycle of the Moon to release their eggs at the same time,
08:17when stronger tides help to transport their eggs.
08:23Baby sea turtles use the light of the Moon
08:26shining on the water to guide them from their birthplace to the ocean.
08:29Who knows what direction life on Earth would have taken
08:32if, at some point, a few billion years ago,
08:36we did not have our lunar companion to accompany us?
Comments