Final answer:
John Jacob Astor IV was the richest man aboard the Titanic with a net worth of $2 billion in today's money.
Step-by-step explanation:
The richest man aboard the Titanic, with a net worth that would be about $2 billion in today's money, was John Jacob Astor IV. He was a prominent American businessman, real estate developer, investor, inventor, writer, lieutenant colonel in the Spanish-American War, and a prominent member of the Astor family. Astor's fortune was derived from his family's investments in real estate and his own successful business ventures.