The Drake Equation – What are the Chances of Extraterrestrial Life?


Are We Alone in the Universe?

Calculate the Chance of Intelligent Alien Life with the  

In 1961, Astronomer Frank Drake came up with an equation to estimate how many detectable extraterrestrial civilizations might exist in our galaxy. Each variable is a crucial factor for the development of alien life.

today’s optimistic
lowest possible
original drake values
today’s skeptical

At 13.2bn years, the Milky Way is almost as old as the universe itself.

​With advanced telescopes, we can now identify planets larger than Earth in other solar systems (exoplanets). 40%+ of sun-like stars have planets, but many are undetectable. So it may be closer to 100%.

Much debate surrounds this key number. Many exoplanets are outside the habitable zone for life or are too close to superhot parent stars.

​Drake assumed all Earth-like planets develop organic life. Using Earth as evidence though makes life seem inevitable. Discovering life on Mars or elsewhere would dramatically resolve this uncertainty.​

Hotly debated! Skeptics point out that from billions of species, just one has become intelligent. Others argue that life evolves towards complexity - so intelligence is inevitable.

Would alien life ever invent radio? Even an advanced civilizations might only progress to agricultural-level technology like the Roman or Chinese empires.

How long does a civilization last? Could a society overcome all threats to its survival and then endure for millions of years?

Optional addition allows for the chance of civilization to re-evolve after collapse. An intuitive addition if you consider the billion year lifespan of planets.

The Drake Equation & The Seager Equation – Calculating the chance of extraterrestrial life

The Drake Equation reveals the statistical chance of life on other planets. Are we alone in the universe? Or has the Fermi Paradox put the kibosh on Drake’s Equation? What did your calculations reveal about the current chances of intelligent alien life in the universe?

UPDATE: We’ve added the less well-known but more modern Seager Equation (PDF) to the mix.

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