Show Notes:

• Are we alone in the cosmos?

  • The Drake Equation

    • In 1961, scientist Frank Drake wrote down a simple-looking equation for estimating the number of active, technologically-advanced, communicating civilizations in the Milky Way

      • While the equation itself has its flaws it has still helped spark the modern interest in life outside our planet

• • Life happened relatively quickly in Earth’s history and with the most common ingredients in the universe

  • During the period of Heavy Bombardment early in the development of the solar system, it’s possible that Mars life was transferred to Earth via impacts from comets or asteroids

    • This would show that life can begin on more than one planet in a given solar system increasing the likelihood of life elsewhere

• • The Fermi paradox, named after Italian-American physicist Enrico Fermi, is the apparent contradiction between the lack of evidence for extraterrestrial civilizations and various high estimates for their probability

    • There are billions of stars in the galaxy, many of which have Earth-like planets, and if Earth is fairly typical, some of these may have developed intelligent life. Many of us on Earth are working to develop interstellar travel, and even though the galaxy is 100,000 light years across, we’ve been around for many billions of years. If life is common, then where is everyone?

• So why haven’t we found anything yet?

  • Space is big. The Milky Way alone is 100,000 light years across, so it’s conceivable that the focused signals of intelligent aliens, which are limited to the speed of light, simply haven’t reached us yet

  • The universe is a deadly place. On cosmic timescales – think billions of years – life may be fleeting. All it takes is a single asteroid, supernova, gamma ray burst, or solar flare to render a life-harboring planet lifeless

  • Apart from a few efforts to broadcast strong signals over a narrow frequency band towards the stars above, we’ve barely made our presence known in the universe. In fact, if aliens have radio telescopes similar to what we have on Earth, our television and radio broadcasts would only be detectable up to 0.3 light-years away. That distance doesn’t even transcend the farthest reaches of our solar system

  • Given the lifespan of the Milky Way galaxy alone, space faring civilizations could have been born, lived and died over the course of hundreds of millions of years without ever overlapping one another

Sources:

The Fermi Paradox II — Solutions and Ideas – Where Are All The Aliens? - Kurzgesagt – In a Nutshell

The Fermi Paradox — Where Are All The Aliens? (1/2) -  Kurzgesagt – In a Nutshell Youtube

The Drake Equation Is Broken; Here's How To Fix It - Forbes

12 Possible Reasons We Haven't Found Aliens - Space.com

Human evolution - Smithsonian National Museum of Natural History

What are the odds there is life in outer space - Richard Dawkins asks Neil Degrasse tyson -  Cosmology Today™ Youtube

The Cosmic Distance Scale - Goddard Space Flight Center

A Brief Explanation of the Kardashev Scale: How Far Can Humanity Really Advance? - Futurism

Fermi Paradox: Where Are the Aliens? - Space.com