David Rumsey Historical Map Collection

1850 Star Chart

(via aquarian-moon-child)

An eruption on the volcano island of Gaua in the south Pacific, observed from the International Space Station, May 2013.

(Source: *Slate*, via traveler-wanderer)

Spiral of TheodorusFirst constructed by Theodorus of Cyrene, the spiral (also called the square root spiral, Einstein spiral or Pythagorean spiral) is composed of contiguous right triangles. It is begun with an isosceles right triangle with each leg having a length of 1 - then another right triangle is formed next to it with one leg being the hypotenuse of the prior triangle and the other leg having a length of 1.Thus, each successive nth triangle has side lengths √

nand 1, with a hypotenuse of √(n+ 1).

(Source: quantumaniac, via thinksquad)

The essence of philosophy is that a man should so live that his happiness shall depend as little as possible on external things.Epictetus (via liberatingreality)

(via prometheanreach)