As he tells it, his life story sounds like a cerebral version of "Forrest Gump" — Loeb always singemindedly pursuing his science and intersecting with the giants of the field, whom he regularly name-drops. Stephen Hawking had dinner at his house. Stephen Spielberg once asked him for movie tips. Russian billionaire Uri Milner once walked into his office and sat on the couch and asked him to help design humanity's first interstellar spaceship — which he is now doing, with a research budget of $100 million and the endorsement of Mark Zuckerberg and the late Hawking.