Every other celestial sky is either nearly all cloud or almost no cloud — what makes Earth’s perfect balance in achieving about half cloud so unique?



Obviously water and our atmosphere are the biggest factors here, as those are unique to us and are directly correlated with clouds—but why more specifically does this balance seem so fragile?

What could cause a tip in either direction? Is it possible a planet on each extreme could become more like us?

In: Earth Science

Every bit of Earth is perfectly balanced to create our atmosphere. Its size, relation to the sun, our moon’s size and distance, the fact that we have oxygen, the gravitational pull, the magnetic poles, everything is a factor to perfectly balance it.

Our atmosphere *is* all cloud. It’s a cloud of nitrogen, oxygen and carbon dioxide. In order to survive on Earth, we’ve evolved to see the wavelengths of light that pass through our atmosphere.

People say humans and technology isn’t a part of nature, but surely it is because we are nature and the ability to do what we do is because nature has made us this way? 🙂

The simple answer is that our atmosphere is just right to make clouds the way it does. It is hot enough to evaporate water and cool enough for that vapor to turn back into water. Our atmosphere is also just right to trap some of the heat from the sun and let some of it escape. If the average temperature got high enough then the vapor wouldn’t be able to turn back into water and water vapor is a greenhouse gas. So the atmosphere would get thicker and trap more heat, melting more water, trapping more heat, melting more water, trapping more heat, etc.

Venus used to have a temperate climate and liquid water and all of the ingredients for life, much like Earth, but as the sun got hotter the water evaporated and the planet fell into a cycle of runaway climate change like the above. Venus is a big reason that we understand climate change as much as we do. It’s a perfect model of what *could* happen on Earth.

Mercury has no atmosphere and Mars has a very thin atmosphere so they don’t hold the heat of the sun like Earth does. They also lack abundant amounts of gasses that could form many clouds. That’s why they don’t have clouds like we do.

Far far into the future, when the sun gets hot enough, Earth will go through the same phases that Venus went through and will eventually become a dead planet. The temperature on Mars will eventually become what Earths is now, but since mars lacks a magnetic field it has nothing to block solar radiation so it wouldn’t become “like Earth.”

The gas giants are just that. Huge balls of gas. They don’t have a solid rocky core so the could never become like earth.