Introduction: Are We Alone? (01:11)

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Earth is home to eight billion humans; the sun is one of 300 billion stars in the Milky Way, one of 100 billion galaxies in the universe. Scientists build tools to hunt for life outside our world.

Flickering Discovery (03:03)

Astrophysicist Tabetha Boyajian studies the unusual fluctuations of a star 1,500 light years from Earth; dimming is too intense to be planetary. After many theories tested, some scientists suggest the anomaly is caused by an alien mega-structure built to harness energy.

Dimming Data (05:03)

In 2009, Keplar Space Telescope launched to discover planets capable of hosting life; it detects starlight flickers, indicating orbiting bodies. It has found 3,000 within habitable zones of their respective solar systems.

Hostile Suns (06:58)

Astrophysicist Jason Kalirai studies stars at the Space Telescope Science Institute; he explains that all have orbiting planets, but many are Red Dwarfs and difficult to detect. He researches the Trappist-1 System, concluding that solar radiation prevents life from establishing within it.

Reading Biosignatures (04:51)

Sara Seager endeavors to find life in nearby planetary systems using Transiting Exoplanet Survey Satellite data. Lifeforms emit gasses that accumulate in the atmosphere; their interactions with light vary and can be read.

Sensitive New Technology (02:37)

Mercedes Lopez-Morales asserts oxygen must be present in a planet’s atmosphere for life to be discovered there, but its signature is faint. She hopes that the Magellan Telescope will detect it; it includes the largest mirrors humans can construct.

Local Microbes (07:50)

Astrobiologist Kevin Hand searches for extremophiles within the solar system; moons Enceladus and Europa have ice covered oceans. He experiments with glycine finding that it emits a clear signal after subjected to reconstructed conditions.

Exploring Under Ice (04:45)

In order to probe Europa’s oceans, Engineer William Stone is designing Sunfish. Long distance transmissions are delayed, rendering remote control useless; the robot must learn to navigate using sonar. He and his team code problem solving strategies into the machine.

Searching for Intelligence (03:19)

Microbes evolved into the diverse and complex lifeforms on Earth; the probability they would similarly develop elsewhere is debated by scientists. Existence of other sentient beings is probable given the billions of potentially habitable planets in the universe.

Hunting Space (03:53)

Jill Tarter co-founded SETI Institute, dedicated to the search for intelligent alien lifeforms; she uses the Allen Telescope Array to search for irregular radio waves. There are billions of possible frequencies; time and technology are required to study them.

Light Signature Solution (03:25)

Boyajian’s discovery of the erratically dimming star inspires more research; networks of ground based telescopes now monitor it constantly. New data suggests that space dust causes the intense flickering.

Unique or Common (03:06)

Scientists discuss why intelligent life has not made contact with humans; some theorize that interstellar travel is too difficult. The universe is massive with billions of galaxies; probability dictates existence of extra-terrestrials is very possible.

Credits: Are We Alone? (01:05)

Credits: Are We Alone?