I found this video very interesting. The part I found most fascinating was the fact that we know very little about the universe. We do not know if space is finite, or if it is infinite. We do not know, how space started. We don't even understand the wave-particle duality of light and quantum theory.
The video we watched explained the concept of cosmic rays: rays that originate from stars going supernova, orbit the star due to magnetic attraction, and then fling out due to centrifugal force, speeding out into space at nearly the speed of light. I do not deny nor support the existence of extraterrestrial life due to inconclusive evidence.