The subject of the Earth's evolution in space is one on which geologists and physicists have dwelt from the point of view of time, with regard to certain facts about the origin of the planets. The classical theory is that, vast years ago, the sun was a spinning and flaring mass of matter, considerably larger than it is now. As it continued to whirl, a series of fragments were detached from it by the approach of other bodies flying through space. The torn-off fragments became the planets, one of which was the planet Earth. The flaming mass that was the earth's material broke into two masses, as it continued to spin, the larger one being the earth itself and the smaller one being the moon. One can imagine the speed of the whirling that had detached the masses that formed other bodies of stars and planets. At first, the earth was a flaming, barren mass where no life could live. Over millions of years, the flaming incandescence began to gradually cool, as the spinning began to slow down. There was a time when the day was not even a half or a third of what it is today, while the blazing sun was much hotter than what it is presently.
How long has the world endured is a question that remains to be an enigma. Some scientists presume that the age of our planet, Earth, is approximately 2,000 million years, the age of the sun being about five million, million years. It is estimated that the planet Earth's equatorial temperature might be sinking to Arctic conditions, in due course.
There are convincing reasons for supposing that sun and earth and moon, and the entire system were then whirling at a speed that was much greater than their speed today. The sun is presently much cooler than it was, spinning more slowly than it did originally, as it continues to cool and slow down, while, at the same time, the rate at which the earth keeps spinning is diminishing. Some scientists think that there will be a time when the day will be as long as a year is now, while the cooling sun will hang motionless in the heavens.
The opposing theory that dwells on Intelligent Design (the creation of the Universe by God) is a separate topic on how and who had caused the Big Bang. This question remains unanswered, thus confirming the belief by religionists that, in the absence of any convincing answer, the one and only source would assuredly be God Himself.