Ah.... those days I was able to lecture GR

Astro Pic Of The Day (@apod) tweetou às 5:30 AM on ter, Jul 02, 2013: Circling a Black Hole at its Photon Sphere : http://t.co/i2LKZ0dYCd (https://twitter.com/apod/status/351920688522727424) Adquira o aplicativo oficial do Twitter em https://twitter.com/download