The sun’s gravity keeps Earth in orbit around it, keeping us at a comfortable distance to enjoy the sun’s light and warmth. It holds down our atmosphere and the air we need to breathe. Gravity is what holds our world together.

The planets do not fall into the sun because they are moving too fast in the tangential direction. As they fall toward the sun they travel tangentially just enough that they never get very close to the sun. They fall around it, in effect.

The centripetal force requared by the earth for revolution around the sun is provided by gravitational pull of sun on the earth, In other words, gravitation pull of sun on earth up in providing necessary centripetal force required by the earth for revolution around the sun. Hence the earth does not fall into the sun.

Scientists estimate that the Sun will die in around 5 billion years. If the Sun miraculously disappeared, the Earth (and all the other objects in the Solar System) would continue their forward motion in a straight line off into space, instead of following their almost-circular orbits.

Scientists have found an abrupt change about 6,000 years ago in how terrestrial plant and animal species coexisted, right about the time human populations were ballooning and agriculture was spreading around the world. Egyptian farmers in the Neolithic period 5,000-6,000 years ago.

The 4th millennium BC spanned the years 4000 through 3001 BC. Some of the major changes in human culture during this time included the beginning of the Bronze Age and the invention of writing, which played a major role in starting recorded history.

30,000 BC: Last stands of Homo erectus (Java) and Neanderthal (Spain) species, decline in favor of Homo sapiens (NYT, 12/13/96). Paleolithic cave arat in Europe.

3000 BC – Sumerians start to work in various metals. c. 3000 BC – Knowledge of Ancient Near Eastern grains appears in Ancient China. 3000–2000 BC – Settled villages are widespread in Mesoamerica.