The document discusses the theory of planetesimals to explain the formation of the solar system and Earth. It describes how: 1) A gas and dust nebula received an expansive wave from a supernova, causing it to rotate and collapse into a disk with matter accumulating in the center to form our sun. 2) Planetesimals formed as small bits of matter collided and joined together, eventually creating the planets. The outer planets attracted gas to become gas giants, while inner planets like Earth took longer to form and remained smaller without gas. 3) Earth underwent multiple events since forming 4.6 billion years ago, allowing its history to be divided into eons such as the Hadean, Arche

1. THE HISTORY
OF THE EARTH
4º
SERGIO SALOBREÑA
LUCENA
MIJAS

2. ORIGIN OF THE SOLAR SYSTEM
THE CURRENTLY ACCEPTED THEORY TO EXPLAIN THE FORMATION OF THE
SOLAR SYSTEM, AND THE OWN EARTH IS THE THEORY OF THE
PLANETESIMALS:
1. A GAS AND DUST NEBULA, FLOATING IN SPACE WITH VERY SLOW
MOVEMENTS BETWEEN ITS PARTICLES TILL IT RECEIVED THE EXPANSIVE
WAVE OF THE EXPLOSION OF A NEARBY SUPERNOVA.
2. THE NEBULA BEGAN TO ROTATE MUCH FASTER, AND TO COLLAPSE IN A
SINGLE PLANE.
3. IN THE CENTER OF THE NEBULA, THE ACCUMULATION OF MATTER AND
THE CONTINUOUS SHOOTS INCREASED THE PRESSURE AND THE
TEMPERATURE, ALLOWING THAT THEY WILL BEGIN TO NUCLEAR
REACTIONS. THAT WAS BORN OUR SUN FROM A PROTOSOL.

3. ORIGIN OF THE SOLAR SYSTEM
4. OUR CENTRAL STAR ATTRACTED 99.85% OF THE MATTER AND GAS OF
THE SYSTEM, BUT THE REST WAS ABLE TO SEPARATE AND THROUGH
THE ROCK LINE, WHERE THERE WAS PIECE OF MATTER AND EVEN
FURTHER, AFTER THE FREEZING LINE GASES WERE SOLIDIFIED AS
WATER VAPOR, METHANE, ETC.
5. SMALL BITS OF MATTER, THEY WOULD BEGIN TO COLLIDE WITH LITTLE
VIOLENCE AND JOIN IN AGGREGATES OF GREATER SIZE CALLS
PLANETESIMALS, WHICH WOULD IMPACT THEMSELVES, INCREASING
SIZE UNTIL FORMING THE PLANETS.
6. THIS PROCESS WAS FASTER IN THE FORMATION OF THE EXTERNAL
PLANETS BECAUSE THERE WERE MUCH MORE GREAT AMOUNT OF
FLOATING PARTICLES. ONCE THESE PLANETS REACH A DETERMINED
SIZE, THEY BEGIN TO ATTRACT THE GAS AND MATTER THAT SURROUND
THEMSELVES WITH GRAVITATORY FORCES, BECOMING GASEOUS
GIANTS (EXTERNAL PLANETS).

4. ORIGIN OF THE SOLAR SYSTEM
7. IN THE AREA LOCATED BETWEEN THE ROCK LINE AND THE FREEZING
LINE, WHEN THE TEMPERATURE IS GREATER, GAS IS SCARCE AND THE
ROCK PARTICLES IN SUSPENSION ARE LESS ABUNDANT, SO THAT IT
TAKES MUCH MORE TIME TO FORM THE PLANETS FROM
PLANETESIMALS. IN ADDITION TO THE NO GAS, THERE CAN ONLY
ATTRACT ROCK FRAGMENTS, SO THE INTERIOR PLANETS WILL BE LESS
SIZE THAN THE EXTERNAL PLANETS.
8. THE EARTH IN ITS FIRST STAGES WAS ACCOMPANIED BY ANOTHER
PROTOPLANET CALLED CEIA, FINALLY COLLISED, WINNING THE EARTH
MASS AND A MOON. FINALLY 4500 M.A. AGO, THE EARTH IS STABILIZED
AND BECOMES ONE OF THE INTERNAL PLANETS.

5. ORIGIN OF THE SOLAR SYSTEM
7. IN THE AREA LOCATED BETWEEN THE ROCK LINE AND THE FREEZING
LINE, WHEN THE TEMPERATURE IS GREATER, GAS IS SCARCE AND THE
ROCK PARTICLES IN SUSPENSION ARE LESS ABUNDANT, SO THAT IT
TAKES MUCH MORE TIME TO FORM THE PLANETS FROM
PLANETESIMALS. IN ADDITION TO THE NO GAS, THERE CAN ONLY
ATTRACT ROCK FRAGMENTS, SO THE INTERIOR PLANETS WILL BE LESS
SIZE THAN THE EXTERNAL PLANETS.
8. THE EARTH IN ITS FIRST STAGES WAS ACCOMPANIED BY ANOTHER
PROTOPLANET CALLED CEIA, FINALLY COLLISED, WINNING THE EARTH
MASS AND A MOON. FINALLY 4500 M.A. AGO, THE EARTH IS STABILIZED
AND BECOMES ONE OF THE INTERNAL PLANETS.

6. THE HISTORY OF THE EARTH
• SINCE ITS FORMATION 4600 M.A. AGO MULTITUDE OF EVENTS ON THE
EARTH
HAS HAPPENED, WHICH HAS ALLOWED TO FRACTION TIME IN EONS, ERAS
AND
PERIODS FOR ITS BEST STUDY. CURRENTLY 4 EONS ARE RECOGNIZED:
1. HADIC EON (4500-3600 M.a.)
2. ARCHAIC EON (3600-2500 M.a.)
3. PROTEROZOIC EON (2500-540 M.a.)
4. FANEROZOIC EON (540-NOW)

7. HADIC EON
CALLED IN HONOR TO HADES, HELL IN GREEK MYTHOLOGY, DUE TO THE
CONDITIONS OF THE EARTH DURING THIS TIME. THE EARTH IS IN ITS
FORMATION PHASE, METEORITES FALL CONTINUOUSLY INCREASING ITS
TEMPERATURE, BEING INITIALLY AN AUTHENTIC SEA OF LAVA TO MORE THAN
1000º C.
THE EARTH BEGINS TO COOL AND A VERY UNSTABLE SOLID BARK IS
FORMED, BECAUSE IT IS ON A FUNDED LAYER AND THE IMPACT OF
METEORITES. GASES RELEASED FROM THE LAVA WILL GENERATE THE
ATMOSPHERE (RICH IN CO2 AND WATER VAPOR) AND THE HYDROSPHERE.
THE OLDEST ROCKS FORMED AT THE END OF THIS STAGE, 3600 M.a. AGO.

8. HADIC EON

9. HADIC EON
THE APPEARANCE OF WATER ON THE EARTH IS A MYSTERY
STILL, IT IS CURRENTLY BELIEVED THAT MOST OF THE WATER
ARRIVED IN ASTEROIDS AND COMETS WITH HIGH CONTENT IN
WATER THAT COLLIDED WITH THE EARTH IN FORMATION. THIS
WATER WAS EVAPORATED ON THE SURFACE, AND THE
WATER VAPOR ASCENDED IN IMMENSE AMOUNTS FORMING
THICK CLOUDS, TRIGGING A HUGE DILUVIUM THAT LAST
MILLION YEARS.

10. ARCHAIC EON
GEOLOGY: THE FIRST ROCKS ARE METAMORFICAL OR
VOLCANIC, WHILE THE ATMOSPHERE IS FORMED BY
METHANE (CH4) CARBON DIOXIDE (CO2) AND AMMONIA (NH3).
WEATHER: THE SUN IRRADIAED LESS ENERGY THAN NOW,
HOWEVER, THE TEMPERATURE WAS ABOUT 30 ° C ON THE
SURFACE AND BETWEEN 30-40 ° C IN THE OCEAN DUE TO THE
GREAT GREENHOUSE EFFECT OF THE CO2 RICH
ATMOSPHERE.
LIFE: THE FIRST LIVING BEINGS CAME UP 3500 M.a. AGO. THEY
WERE PROCARIOTS CELLS, FILAMENT BACTERIA LIVING IN
THE ARCHAIC OCEANS. THE PHOTOSYNTHESIS PROCESS
COMES UP AND THE ATMOSPHERE ENRICHES IN O2.

11. ARCHAIC EON

12. ARCHAIC EON