Tidal Hypothesis

"Tidal Hypothesis"

This theory was proposed by Sir James Jeans and Sir Harold Jeffreys in 1925. It considers that the Earth originated as a hot mass and cooled slowly to develop a crust. On the other hand, the inner part is explained as still liquid because of the slow process of heat loss.

According to this theory, a large wandering nebula came very close to a smaller nebula (sun). Due to the gravitational pull of the large nebula, it caused a tidal increase of matter on the surface of the sun. When this large nebula began to move away, the matter on the sun's surface rises as a tidal wave and was drawn to a distance from which it could not return back to the sun. Then, it was detached to the sun's body.

As it cools down, this matter condensed to form planets (including Earth) and planetoids. These planets soon started to revolve around the sun.

The cigar-shaped arrangement of the planets strengthens the view that this theory is close to reality, having the smallest planets located closest from the sun and the larger ones occupied the intermediate positions.

However, there are still objections which arose from this hypothesis. First, impartation of angular momentum to detach a gaseous mass is impossible for such a passing star. In addition, a hot gaseous mass which was detached from a nebula will deplete in space.