Illustration: Aïda Amer/Axios

More than 30 intelligent alien civilizations could exist in the Milky Way, according to a new study in The Astrophysical Journal.

The big picture: Scientists have long tried to estimate how many alien civilizations like our own could be out in the universe.

  • The Drake Equation is most famous, but the new study uses a simple way to estimate exactly how many intelligent civilizations could be lurking in our galaxy.

What they did: The new study uses Earth as a model for how life may form in other parts of the Milky Way.

  • "There should be at least a few dozen active civilizations in our galaxy under the assumption that it takes 5 billion years for intelligent life to form on other planets, as on Earth," Christopher Conselice, co-author of the study, said in a statement. "The idea is looking at evolution, but on a cosmic scale."
  • The new estimate factors in the likelihood that stars host Earth-like planets in their habitable zones and the history of star formation throughout the galaxy.
  • Under the study's strictest set of assumptions — which includes that stars that could host planets with intelligent life be similar in metal content to our Sun — the authors expect there should be 36 alien civilizations in the galaxy.

But, but, but: Even if there were three dozen intelligent civilizations in our galaxy, there's no guarantee that we'll ever interact with any of them.

  • According to the study, on average, these civilization are likely about 17,000 light-years away.

Go deeper

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Sep 15, 2020 - Science

What it would mean to find life on Venus

Illustration: Annelise Capossela/Axios

Scientists think they may have found an indicator of life in Venus’ clouds — a discovery that, if confirmed, will cause them to re-examine everything they thought they knew about how life evolves.

The big picture: If life does exist within a small niche of habitability in Venus' temperate layer of clouds, it might mean that life could be even more ubiquitous in the universe than previously expected. The discovery is already fueling calls from scientists who want a mission sent to the nearby world.

Amy Harder, author of Generate
3 hours ago - Energy & Environment

Climate change goes mainstream in presidential debate

Photo illustration: Aïda Amer/Axios. Photo: Olivier Douliery-Pool/Getty

The most notable part of Thursday’s presidential debate on climate change was the fact it was included as a topic and assumed as a fact.

The big picture: This is the first time in U.S. presidential history that climate change was a featured issue at a debate. It signals how the problem has become part of the fabric of our society. More extreme weather, like the wildfires ravaging Colorado, is pushing the topic to the front-burner.

Finally, a real debate

Photo: Morry Gash/AP

A more disciplined President Trump held back from the rowdy interruptions at tonight's debate in Nashville, while making some assertions so outlandish that Joe Biden chuckled and even closed his eyes. A Trump campaign adviser told Axios: "He finally listened." 

The result: A real debate.