How were Uranus, Neptune, and Pluto first discovered? Neil deGrasse Tyson explores the often un-discussed past failures in astrophysics and why “how tall are you?” is an unanswerable question.

What is the Earth’s ellipticity? What is the sun’s diameter? How do you measure the edge of something that is made out of gas? Neil breaks down how measurements are inexact and the idea of scientific uncertainty. Learn about Galileo’s discovery of Jupiter’s moons, the search for Planet X, and the later discoveries of Uranus, Neptune, and Pluto. Find out about the planet, Vulcan, that scientists proposed to explain Mercury’s orbit. Plus, naturally, Neil breaks down the density of the The Hulk. […]