THE PAST AND FUTURE OF HABITABLE PLANETS
Starting of Planet VENUS 4.6 billion years ago, Tiny planetesimals/rocks combined to from Venus. 4 billion years ago, A giant object hit VENUS forming a moon (similar to how our moon formed).
4 billion years ago (10 million years after first impact), Another Giant object hit Venus, which reversed it’s direction of rotation. Venus lost its moon as the spiralled inwards & merged back with the planets.
3 billion yeasr ago Venus had shallow water oceans on it’s surface, surface temperature was habitable.
2.5 billion yeras ago, Venus’ early oceans evaporated due to proximity to sun. Carbondioxide dominated the atmosphere causing “Runaway Greenhouse effect leading to high temperatures.
VENUS is the hottest planet in the solar system, Even lead can melt on its surface
100,000 years from now, Cloud cities will float on VENUS’ clouds, where conditions (temperature & pressure) are similar to EARTH.
5 billion years from now, The Red Giant Sun will swallow VENUS.
Next up planet EARTH, 4.55 billion years ago, Small objects in the solar system clumped together to from EARTH. 4.52 billion years ago, A MARS sized object collided with EARTH to form MOON. A day on EARTH was just few hours long.
4 billion years ago, EARTH suffered heavy bombardment of asteroids. These asteriods brought water and organics to our planets-ingredients for life. 3.5 billion years ago, the first life form on Earth emerged (possibly near hydrothermal vents.
2.8 to 3.6 billion years ago, The first known supercontinent (Vaalbara) formed. 3.2 billion years ago, Firts oxygen-producing organisms formed. 2.3 Billion years ago, Earth atmosphere became oxygen-rich, This triggered the snowball Earth period where the temperatures dropped severely low.
2.1 Billion to 225 million years ago, different supercontinents kept on forming. 65 Million years ago, A 10 km sized asteroids collided with Earth, wiping out 75% of the species (including dinosaurs). 2 Million years ago, The first humans (primitive) appeared on Earth.
Today, Earth is the only known planet to support life. Humans have brought about a lot of changes on the planet. Some of which not good for the planet. 250 Million years from now, A new supercontinent ‘Pangea Ultima’ will form. 1 Billion years from now, Occeans will start evaporating due to increase in sun’s luminosity. 7.59 Billion years from now The red giant sun will finally swallow Earth.
Next up planet Mars. 4.6 billion years ago, small objects in solar system clumped together to form mars. 4.5 billion years ago, magma oceans flowed on Mars. 4.4 Billion years ago, Magnetic field activated on Mars. 4.3 Billion years ago, Debris rings forms around Mars after collision with a huge object. 4.2 Billion years ago, Carbon dioxide ice clouds form. (Mars gets warmer). 4.1 Billion years ago, Water Ocean/lakes form. Rainfall begins.
3.8 Billion years ago, Life began on Mars (Meanwhile life began on Earth at the same time). 3.8 Billion years ago, Mars’ molten core cooled down it began to lose atmosphere. Mars began to lose its water and atmosphere remaining water condensed to form Ice.
3.1 Billion years ago, Mars became a dead and cold planet,(Life was dead). Today, Mars has a thin atmosphere. Human robots and rovers have occupied Mars. 100,000 years later, Mars terraformed by Humans. 50,000,000 years later, Mars moon Phobos falls into mars and is crushed by mars gravity to form rings around red planet.
4-5 Billion years later, Mars is stripped off of everything when Sun becomes a Red Giant.
