The earth sits comfortably in its orbit. Earth’s axis of rotation is tilted at an angle of 23.5 degrees. Earth’s orbit around the sun.
Knock the planet over and it wouldn’t be the Earth as you know it. The question arise in your mind!! How can the axial tilt change the planet uninhabitable? So, here’s what would happen if the Earth’s axis was tilted by 90 degrees? Only two planets in the solar system lie on their sides which is Uranus and dwarf planet Pluto. Now, if something took the Earth off its stand, it would have no chance of developing any complex life on its surface.
But, let’s start from beginning!!
The axial tilt, or obliquity, is what drives the season here on earth. Before the collision that created the Moon, The earth’s axis was slowly wobbling around between 0 and 85 degrees. Then, our newly formed Moon stabilized it. If that collision happened at a different time, then the things would turn out very different here on earth.It would be strangely a new world. One hemisphere would be shrouded by darkness for 6 months straight, while the other would be getting cooked by the blazing sunlight. One day on earth would last a whole year. At the North Pole, the daytime temperatures would rise to a boiling 50°C. A day at the south pole would be even worse because the South Pole would be located away from climate-controlling ocean currents,it would heat up to an almost boiling 80°C. The poles would soak up so much heat from the sun,that they wouldn’t even freeze during the 6 months long night. You wouldn’t recognize the steaming equatorial tropics.
90 degree of axial tilt, then the part of the equator would stay encased in ice all year round. At some point in this Earth’s existence, our continents would get clumped together around one of the poles. Inland temperatures in the daytime would get truly hellish, reaching the boiling temperate of water. Clouds could help the situation and not let all the water vapor off the planet but you wouldn’t know.In this scorching heat, the best case scenario would see just a few kinds of bacteria survive. Those bacteria might evolve into more complex life form, but they wouldn’t be anywhere close to how complex we turned out to be. The reason would be a lack of oxygen. Green plants would be having a hard surviving during the 6 months of complete darkness. They’d drop their seeds at nightfall to grow after sunrise.
But in these conditions would they have been evolved?
Interestingly enough, if the earth was 60 millions km further away from the sun a 90 degree axial tilt wouldn’t be so bad. The temperature at the poles would never raise above 46°C during the day. The night would be 3°C to the coldest. The only place covered with ice would only be the highest mountains areas. So you see, simply orbiting a star in the habitable zone doesn’t mean that a planet is actually capable of sustaining life. We’re the lucky one living here on Earth. One day we might discover another exoplanet.