"Where are they?"
Enrico Fermi (1901–1954) - The Fermi paradox spoken in 1950 regarding the lack of evidence of extra-terrestrial intelligence.
Enrico Fermi (1901–1954) - The Fermi paradox spoken in 1950 regarding the lack of evidence of extra-terrestrial intelligence.
Arthur C. Clarke (1917-2008)
Composition of the Cosmos by Michæl Paukner
According to the latest observational evidence, ordinary matter, including stars and planets, only make up a tiny fraction of the universe (5%). The rest is the elusive dark matter (25%) and dark energy (70%).
Universe by Tang Yau Hoong