Alan Guth explains how eternal cosmic inflation explains the multiverse. Guth says that there is a lot of evidence for inflation. Also, the multiverse would explain the low number for the energy density of vaccuum.
Leonard Susskind explains that string theory proposes that there are 10^500 kinds of universes. Not just 10^500 universes but 10^500 possible kinds of universes.
Inflation results from repulsive gravity existing in the early universe.
Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.
Known for identifying cutting edge technologies, he is currently a Co-Founder of a startup and fundraiser for high potential early-stage companies. He is the Head of Research for Allocations for deep technology investments and an Angel Investor at Space Angels.
A frequent speaker at corporations, he has been a TEDx speaker, a Singularity University speaker and guest at numerous interviews for radio and podcasts. He is open to public speaking and advising engagements.