1) The universe is estimated to be around 13.8 billion years old.

2) The Mariana Trench in the western Pacific Ocean is the deepest part of the world's oceans, reaching a depth of approximately 36,070 feet (10,994 meters).

3) The first successful human heart transplant was performed by Dr. Christiaan Barnard in 1967.

4) The word "book" contains two vowels: O and O.