The Universe is 13.8 billion years old, the planet Earth 4.5 billion years old. Dinosaurs were on the Earth from 250 million years ago to 65 million years ago, that 185 million years of domination. Homo Sapiens Sapiens - modern humans 130,000 years ago to the present, and are destined to last...
Nobody knows the actual size of the Universe. If it is infinite then life elsewhere is certain. Alternatively the odds are stacked in favour of life elsewhere. 400 billion stars in a galaxy x 500 billion galaxies is a LOT of stars with half a dozen planets in each solar system. The fact that...
Our Solar System is just one member of the Milky Way galaxy with 200 to 400 billion stars. The current estimate is that there are 100 to 200 billion galaxies in the Universe, each of which has hundreds of billions of stars. A recent German supercomputer simulation put that number even higher...