Dark matter candidates
Everybody loves a mystery, and one of the best mysteries in physics is dark matter. As to where it starts, check out Brian Koberlain who said its origins can be traced to the 1600s. Or Alexis Bouvard who in 1821 said anomalies in the orbit of Uranus could be caused by dark matter. Or see the Ars Technica history of dark matter article by Stephanie Bucklin. She said in 1884 Lord Kelvin concluded that “many of our supposed thousand million stars, perhaps a great majority of…