Venus is earth twin when it comes to sizemass and composition of materials present but still it cannot support life What could be a possible reason for this?

Answer 1

Venus is particularly hot due to the greenhouse effect!

As you probably know, carbon dioxide is a greenhouse gas. Various wavelengths can pass through this invisible gas, but it's very effective at trapping heat. Light from the Sun strikes the ground of Venus, and warms it up. The ground tries to radiate heat back into space but the carbon dioxide traps much of it around the planet keeping it so warm. This is the same thing that happens when you keep your car windows closed on a hot day.

Scientists think that Venus used to be more similar to Earth, with lower temperatures and even liquid water on the surface of the planet. At some point, billions of years ago, the planet started to heat up. At some point, all the water on the surface evaporated into the atmosphere. Water vapor is an even more powerful greenhouse gas than carbon dioxide and this caused temperatures to rise even more. Then the surface of Venus got so hot that the carbon trapped in rocks sublimated into the atmosphere and mixed with oxygen to form even more carbon dioxide. And so today we have a carbon dioxide atmosphere on Venus which is 92 times more dense than Earth's atmosphere at the surface.

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One big difference is that Earth has a particularly massive Moon, while Venus has no satellites. Some scientists have speculated that the Moon may have acted to "skim" some of the excess atmosphere off into space, or that tidal forces might have stirred up the atmosphere early in Earth's history. We don't know everything about how the Earth and Venus developed, and we really don't understand everything that we do know.