Question

what will happen if there would not be any oxygen on earth not even in the core just for 5 seconds​

Answer 1

The most likely answer is that Earth would be a lot like Venus. Oxygen is abundant in our neighborhood of the solar system, being found making up the majority (by mass) of the CO2 in Venus’s atmosphere. It also combined with the iron on Mars to form rust, giving Mars its characteristic red color. Earth has plenty of carbon to combine with, so you would expect elevated CO2 levels in our atmosphere and oceans. The oceans will be able to absorb a lot of CO2 so we would not end up with the extreme greenhouse effect that exists in Venus.

The reason Earth has free oxygen in its atmosphere is because of life. Early in the Earth’s history the atmosphere would be exactly like we described above. Ancient microbes (think algae-like and bacteria-like) lived on this world without oxygen. They eventually evolved to find the process of photosynthesis. For them it was just a way of storing energy. They needed a lot of carbon for this to work, which they got from the C in CO2. To them free oxygen was just a byproduct, but it eventually built up to the point where the majority of the planet went from an anaerobic (without oxygen) environment to an aerobic (with oxygen) environment.

Could life have evolved to the point where we are now without oxygen? Maybe, but it would be much more difficult. You would need an alternate energy source as abundant as the sun. We know whole ecosystems pop up near hydrothermal vents, and these systems use disulfide bonds as their primary energy source. The distance between hydrothermal vents can be quite large, so you don’t get the migrations and adaptations that you get with animals that rely on light and the carbon cycle to exist. It will take a lot longer for these ecosystems to develop into complex life, if they ever get there.

You could also interpret this as “what would Earth look like with no oxygen, not even in molecules.” That is a question that is almost impossible to answer, but from our perspective the answer would be “strange.”

Answer 2

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⭐The day time sky would get darker. Without oxygen, scattering of light would not take place and hence the sky will have a bit less blue colour and a bit more black.

⭐Every living cell would explode in a haze of hydrogen gas. Water has one-third of oxygen and without it, hydrogen would be converted into gaseous state and its volume will expand.

⭐Everyone would get sunburns. Ozone is a molecular oxygen which protects us from UV rays. Without it, we are toast.

⭐The oceans would evaporate. Without oxygen, the hydrogen of water molecule would be converted into gaseous form.

⭐Every building made up of concrete will turn into dust. Oxygen is the main element which binds the concrete structures and without it the compound do not hold their rigidity.