Various mysteries still surround Planet Earth and until now scientists have not been able to solve it from a scientific or scientific point of view. These include our quote from Reader's Digest:
Origin of water
Water is everywhere, covering 70% of the earth's surface and earning it the nickname the Blue Planet. But where did it come from? How can it be so abundant on our planet when it is almost non-existent in the entire Solar System?
Most scientists believe that when it formed about 4.5 billion years ago, Earth was a dry, rocky planet. The most popular scientific theory is that water came in the form of several giant asteroids filled with ice. Another theory says that water actually existed since the formation of the Earth.
The oxygen mystery
Another thing that is very important for living things on Earth is oxygen. According to science, around 2.4 billion years ago, microscopic creatures called cyanobacteria released oxygen as a waste product, filling the atmosphere with it. After that, oxygen levels in the atmosphere fluctuated wildly until they finally stabilized about 540 million years ago.
But what caused it to suddenly stabilize? This remains one of the greatest scientific mysteries for which there is no definite answer.
Cambrian eruption
The Cambrian eruption refers to a complex explosion of life that occurred about 540 million years ago. Previously, life consisted mainly of bacteria, eukaryotes and ultra-simple plants. Early in the Cambrian period, evolution seemed to go through a growth spurt, and complex creatures began to evolve at speeds never seen before.
Suddenly, life had a brain, eyes and a skeleton. Most of the things living today can trace their lineage back to the Cambrian period. Some scientists believe the Cambrian eruption occurred as a result of the oxygen mentioned above, stabilizing at the same time. However, there are still doubts about that theory.
What's inside the Earth's core?
While it may appear that humans have successfully explored Earth, we are only on the surface. There's a lot more to Earth than its surface. However, the exploration is very difficult. The reason, of course, is because the conditions below Earth's surface are simply inhospitable.
Scientists know that the layer beneath the crust, or mantle, is mostly composed of solid silicate rock. But the core of our planet remains a mystery. For years, scientists believed that iron and nickel made up the Earth's innermost layers. But it is not yet fully believed.
How was the Moon formed?
Scientists aren't sure how the Moon formed. Many believe that the moon appeared due to a collision between the newly formed Earth and a slightly smaller protoplanet. However, samples from the Apollo missions show that the Moon's chemical composition is very similar to Earth's.
This suggests the Moon may not be a separate body but was formed from chunks of the Earth itself. The third theory, positing that the Moon is a separate body pulled into Earth's orbit, provides the best explanation for why only one side of the moon is facing us