The size of our Earth
The size of our Earth
The radius of Earth is 6371 km and the radius of Earth Venus is 6051 km. Venus is the only planet that rotates Westwards and Earth and rest of the planets rotate West to East
Venus also rotates eastward. But its rotation period on its axis (243 Earth days) is longer than its orbital period (224.7 Earth days). So from the perspective of the Sun, it appears to slowly rotate backwards.
As for Mercury, it is unclear to me how it would escape from Venus, but attempts to rule it out by computer simulation apparently failed.
If all the planets originate from sun, what makes the surface of planets differ from each other? I am not talking about the presence of water or ice. but the surfaces of Saturn and Venus are extremes. For some reasons..I think that the planets do not belong to mighty sun but matter/debris of some unknown parts of the universe which ultimately fell into sun's orbit by chance.
Mercury could originally have been in a near circular orbit, but visited by a large transient body slipping through the solar system. Alternatively, it could have been a satellite of Venus, and also visited by some large transient body ripping it away from Venus. Either case would have resulted in a modified orbit. Possibly, a large comet of the Sun came close to Mercury, modified its orbit, and broke up the comet into smaller pieces in the process.
As for why the planets the differ, the main theory I've read says that since temperatures closer to the Sun are hotter, only elements which are not vaporized at those temperatures remain close to the Sun, resulting in rocky planets. Lighter elements such as hydrogen and helium would tend to migrate to the outer parts of the system, resulting in gas giants.
Given no atmosphere on Mercury, the high atmospheric pressure and temperature on Venus, and very low pressure on Mars, and now this dependency of meteor impacts to provide carbon for life, it seems like our simplistic understanding of the origin of life on Earth in the context of the universe is starting to crumble.
Carbon decides everything.does not it? I have come across theory which claims that Dinosaurs died after a fierce meteorite attack which killed most of them during the impact and rest due to the dense carbon-dioxide layer that formed and ultimately leading to polar meltdown.
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