Universe, Earth and Life on Earth

Universe Age: 13.72 billion years
Number of Galaxies in Universe: 170 billion
Number of Stars within a Galaxy: 10 million (10**7) to 100 trillion (10**14)
Total Number of Stars in Universe: 17 x 10**17    to    17 x 10**24
Formulation of The Milky Way: 13.2 billion years ago
Formulation of our Solar System: 4.568 billion years ago
Formulation of the Earth: 4.54 billion years ago
Life on Earth, most elemental: 3.8 billion years ago
Life on Earth, fish transition from water to land,
e.g. Tiktaalik:
375 million years ago
Life on Earth, Dinosaurs extinct: 65.5 million years ago
Life on Earth, Homo sapiens existence: 200,000 years ago
Life on Earth, current number of species: 1.5 million known;
2 million to 100 million estimated
Life on Earth, extinct species: 99.9% of all species that ever existed