TED-Ed
Úr Ásta
Why Can't We See Evidence of Alien Life? http://youtu.be/I2apGYUX7Q0 How Many Universes are There? http://youtu.be/a1bWKZFP2Tc
Why Can't We See Evidence of Alien Life? http://youtu.be/I2apGYUX7Q0 How Many Universes are There? http://youtu.be/a1bWKZFP2Tc