3.5 billion years ago, which flora dominated the earth ?

Dinosaurs dominated the earth about

How many years ago life originated on earth?

Consider two nuclei of the same radioactive nuclide. One of the nuclei was created in a supernova explosion 5 billion years ago. The other was created in a nuclear reactor 5 minutes ago. The probability of decay during the next time is

It is said the earth has formed about 4.5 billion years back. How did the earth crust and atmosphere formed according to Big Bang theory?

The earth may have been reversed the direction of its field several times during its history of 4 to 5 billion years. How can geologists know about the earth's field in such distant past ?

The earth may have even reversed the direction of its field several umes during its bustory of 4 to 5 billion years. How can geologists know about the earth's field in such distant past?

The earth may have even reversed the direction of its field several umes during its bustory of 4 to 5 billion years. How can geologists know about the earth's field in such distant past?