Episode 38

The science of the universe

Islam Khan

Apr 13, 2021 | Science

What is cosmology? Are there parallel universes? Why did the universe expand? We explore these questions, and more!

About This Episode

In this episode, I’m speaking with early universe cosmologist Islam Khan. We talk about inflation theory, the multiverse, dark matter, and so much more! Is there such a thing as a parallel universe? Do we know why the universe has stretched? What does a cosmologist do for fun?

Follow Islam Khan on Twitter: https://twitter.com/KhanCosmologist

Islam Khan on LinkedIn: https://www.linkedin.com/in/islam-khan-001915/

Topics and Timestamps


  • (0:00:50) What does a Cosmologist do? 
  • (0:01:48) Islam Khan’s journey into studying cosmology
  • (0:04:50) The Infinite Universe vs The Observable Universe (Correction: Islam meant “billion years”, not “billion light years”!)
  • (0:06:30) The Milky Way in the cosmic web
  • (0:07:50) The scale of the Observable Universe
  • (0:09:30) Are we alone out here? The possibility of alien life
  • (0:11:50) The Inflation Theory – our stretchy Universe
  • (0:12:45) How do we know it stretched?
  • (0:13:30) The painting analogy 
  • (0:14:35) How the Inflation Theory explains these problems
  • (0:15:52) Multiverses: a consequence of inflation. What are they?
  • (0:16:32) Max Tegmark – defining the four levels
  • (0:17:55) Level 1: Inflation fields, Quantum Fields and the Higgs Boson
  • (0:19:24) Level 2: Bubbles of Universes 
  • (0:20:02) Level 3: The Many Worlds Theory
  • (0:22:10) Level 4: An Abstract view: Changing the laws of physics
  • (0:23:30) Do doppelgangers actually exist? 
  • (0:24:20) Wave Function Collapse – Schrödinger’s cat and Hugh Everett’s theory 
  • (0:26:03) Are we just a simulation? 
  • (0:27:25) What caused the inflation? The ball and the hill 
  • (0:29:10) Reheating the Universe 
  • (0:30:25) Unifying Inflation Theory and dark energy/dark matter
  • (0:31:45) The Theory of Everything
  • (0:32:45) The real world applications – answering the big questions
  • (0:34:46) The second stretching phase – what’s happening now
  • (0:35:50) Einstein’s Cosmological Constant
  • (0:37:35) Accelerated Expansion and Earth
  • (0:40:00) Particle Cosmology – not just math
  • (0:41:15) The Philosophical side
  • (0:42:38) The Anthropic Principle
  • (0:43:25) Evidence over opinion – why we can’t all get along 
  • (0:44:45) Working together – you need more than Theorists to make a theory
  • (0:46:25) Exciting advances in research today! Stepping on Mars! New particles and more!
  • (0:49:15) Islam Khan’s interests; soccer, guitar and travel
  • (0:52:25) Science and the arts – is there a link?
  • (0:54:15) Conversations and discussions – other fields of interest 
  • (0:56:20) Research is the dream

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