The exoplanets of TRAPPIST-1: How could there be life?

World Today

NASA artist rendering of TRAPPIST-1 and its exoplanets.

NASA has announced the discovery of the seven Earth-sized planets orbiting a nearby star called TRAPPIST-1. All of these planets appear to have potential for water – advancing the prospect of finding life on planets outside our solar system.

Watch the explainer video by CGTN’s Joshua Barlow:

CGTN’s Daniel Ryntjes reports.

At about 40 light years away in the constellation Aquarius, the TRAPPIST-1 star is a nearby neighbor by cosmic standards. It is roughly the size of our planet Jupiter. The newly discovered planets circle tightly their sun in the so-called habitable zone, where water and, possibly life, might exist. The others are right on the doorstep.

The star and its system was named for the telescope that began this discovery. In early 2016, the TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope) telescope, situated high in the Chilean mountains, found three exoplanets orbiting one such ultra-cool dwarf star 40 light years away. An “ultra-cool dwarf,” means its temperatures are low enough that water can exist on planets that orbit very close to it.

That discovery was followed up by NASA’s Hubble – then later the Spitzer Space Telescope, with assistance from several ground-based telescopes, including the European Southern Observatory’s Very Large Telescope. The Spitzer, an infrared telescope that follows Earth, was well-suited for studying TRAPPIST-1 because the star glows brightest in infrared light.

Over the course of 21 days, Spitzer measured the drop in light as each planet passed in front of the TRAPPIST-1 star. After further analysis, it was determined there were actually seven exoplanets orbiting.

“This discovery could be a significant piece in the puzzle of finding habitable environments, places that are conducive to life,” said Thomas Zurbuchen, associate administrator of the agency’s Science Mission Directorate in Washington. “Answering the question ‘are we alone’ is a top science priority and finding so many planets like these for the first time in the habitable zone is a remarkable step forward toward that goal.”

All of the TRAPPIST-1 planets are closer to their sun than Mercury is to ours. The close distance between planets means distance between them can be measured in days, rather than months and years in our solar system.

Their close proximity to one another also means that the planets are as visible to one another as Earth’s moon is to us.

The planets, currently labeled TRAPPIST-1a thru 1g, may also be in a tidal orbit, which means one side is always facing the sun. This orbit is similar to how Earth’s moon always faces us on one side. This tidal orbit implies that, while life may be sustained on these planets, the weather patterns from one side to the other would be completely unlike anything previously seen.

TRAPPIST 1 Planetary lineup

This artist’s concept shows what each of the TRAPPIST-1 planets may look like, based on available data about their sizes, masses and orbital distances. (Credits: NASA/JPL-Caltech)

As a part of their presentation on Wednesday, NASA released artist rendered video of what the surface of these planets may look like.

NASA also released an update to their application, “Eyes on the Exoplanets,” which allows users to virtually travel to star systems where exoplanets have been discovered and learn about those systems’ physical properties and relationship to the rest of the galaxy. We highly recommend it, and you can download it here.


NASA 360 view of TRAPPIST planet 1D


Leroy Chiao talks about the discovery of 7 ‘earthlike’ planets

Seven earth-sized planets are found around single star called TRAPPIST 1. To discuss the significance of this discovery, CGTN’s Elaine Reyes spoke to Leroy Chiao, former NASA astronaut and International Space Station (ISS) commander.