Why Have We Not Found Any Aliens? - with Keith Cooper

The Royal Institution・2 minutes read

SETI is a scientific quest using radio waves to detect extraterrestrial intelligence, with projects like Breakthrough Listen utilizing machine learning for efficiency. Despite challenges, the ongoing search for alien life explores various methods, including lasers and infrared light, while emphasizing the importance of scientific exploration and preparation for potential contact.

Insights

  • Radio waves are preferred in SETI due to their ability to penetrate interstellar dust, making them ideal for detecting signals from advanced civilizations, as determined by astronomers Philip Morrison and Giuseppi Cocconi in 1959.
  • Breakthrough Listen, spearheaded by Yuri Milner, utilizes machine learning algorithms to enhance the search for extraterrestrial signals by monitoring a million stars, showcasing an ambitious effort to revitalize and expand SETI's scope.

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Recent questions

  • What is SETI?

    SETI stands for Search for Extraterrestrial Intelligence.

  • What is the Breakthrough Listen project?

    The Breakthrough Listen project aims to revitalize SETI.

  • How do lasers aid in space exploration?

    Lasers have advantages over radio waves in space.

  • What are techno signatures in SETI?

    Techno signatures are evidence of extraterrestrial technology.

  • What are the assumptions in SETI's search for alien life?

    Assumptions play a crucial role in SETI's search.

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Summary

00:00

"SETI: Searching for Extraterrestrial Intelligence Among Stars"

  • SETI is a scientific search for extraterrestrial intelligence, not involving flying saucers or UFOs, but a quest to find evidence of intelligent life among the stars.
  • Radio waves are used in SETI due to their ability to pass through interstellar dust, unlike optical signals, making them ideal for detecting signals from advanced civilizations.
  • In 1959, astronomers Philip Morrison and Giuseppi Cocconi determined radio waves as the best means to transmit messages to nearby stars, leading to the focus on radio in SETI.
  • Frank Drake conducted the first radio SETI search in 1960, targeting stars like Epsilon Eridani and Tau Ceti, using radio waves to potentially communicate with extraterrestrial civilizations.
  • The Drake Equation, formulated by Frank Drake, estimates the number of extraterrestrial civilizations in our galaxy based on factors like star formation rate, planets with life, and civilizations transmitting signals.
  • The Breakthrough Listen project, initiated by billionaire Yuri Milner, aims to revitalize SETI by listening closely to a million stars for signals from aliens, significantly expanding the search scope.
  • Breakthrough Listen utilizes machine learning algorithms to sift through vast amounts of data collected from the stars, enhancing the efficiency of the search for extraterrestrial signals.
  • Despite advancements in technology and data analysis, the vastness of our galaxy with 200 billion stars poses a challenge in SETI, requiring patience and thorough exploration to potentially detect signals from other civilizations.
  • The odds of finding a signal from an extraterrestrial civilization remain slim, with the need to search through millions of stars even with the Breakthrough Listen project's extensive coverage.
  • SETI's progress and potential for discovering extraterrestrial signals highlight the ongoing quest to unravel the mysteries of the universe and potentially connect with intelligent life beyond Earth.

14:54

Advancements in Laser Technology for SETI

  • Scientists are exploring various methods to improve the chances of finding alien signals, including using lasers instead of radio waves.
  • The Very Large Telescope in Chile fires lasers at the sky to create an artificial star, aiding in compensating for atmospheric blurring.
  • The National Ignition Facility in California houses a powerful petawatt laser used for nuclear fusion experiments, reaching a thousand trillion watts.
  • Lasers have an advantage over radio waves in space exploration as they do not suffer from dispersion caused by interactions with electron particles.
  • Infrared light can pass through dust, making it a potential tool for observing the universe and searching for alien life.
  • Professor Shelly Wright developed an instrument at Lick Observatory to detect infrared laser pulses, a new approach in SETI.
  • Transits, where planets pass in front of stars, can reveal information about exoplanets, including potential biosignatures in their atmospheres.
  • Techno signatures, evidence of extraterrestrial technology, are being explored in SETI, including the concept of Dyson Spheres for harnessing solar energy.
  • The "Wow! signal" detected in 1977 by the Big Ear telescope in Ohio remains a mystery, possibly indicating extraterrestrial origin.
  • Despite the lack of concrete evidence, ongoing efforts in SETI, including citizen scientists' involvement, continue to fuel interest and research in the search for alien life.

29:58

"SETI's Assumptions and Challenges in Alien Search"

  • The history of SETI is a journey from humble beginnings to current funding from Breakthrough Listen.
  • Assumptions play a crucial role in SETI's search for extraterrestrial life.
  • The search for alien life is based on assumptions of technological intelligence similar to human civilization.
  • The assumption that intelligence equates to technology may not hold true, as seen in the example of dolphins.
  • Detecting alien signals is challenging due to the limited reach of our radio signals in space.
  • Transmitting and receiving signals over vast distances requires significant resources and effort.
  • Altruism in alien civilizations may not be as idealistic as assumed, with kin selection and reciprocal altruism being dominant.
  • Sending messages to potential alien civilizations raises concerns about unintended consequences and potential risks.
  • Initiatives like Breakthrough Starshot aim to send spacecraft to other stars, but technological obstacles remain.
  • Contact with extraterrestrial civilizations could bring about unforeseen consequences, akin to historical events like tulip mania or the impact of modern technology on society.

45:25

"Alien Technology, Contact, and Space Exploration"

  • The potential impact of advanced alien technology, like a replicator from Star Trek, on jobs, economies, and human drive is discussed, highlighting the complexities of such advancements.
  • Concerns about the readiness of humanity for contact with alien civilizations are raised, focusing on the risks of unintended consequences and misunderstandings that could arise.
  • The importance of scientific exploration, particularly in areas related to life, such as cosmology, exoplanet research, and astrobiology, is emphasized as crucial preparation before attempting contact with potential extraterrestrial life.
  • Ongoing and upcoming space missions, like the TESS and ARIEL missions, along with advancements in telescopes and SETI efforts, are detailed as essential steps in understanding and potentially discovering alien life, leading towards responsible contact in the future.
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