NASA @NASA
When a star weighing more than 20 times the Sun runs out of fuel, it collapses and turns into a black hole. But not all black holes are created equal. For #BlackHoleWeek, check out the weird and wonderful black holes of our universe in this @Tumblr blog: https://t.co/Ev3ll3IKmZ https://t.co/rDCWi3uvB7 — PolitiTweet.org