This graphic compares the distance of planets from the host star in the TRAPPIST-1 system and the solar system.
{"Image ImageWidth": "5295", "Image ImageLength": "2978", "Image BitsPerSample": "[8, 8, 8]", "Image Compression": "LZW", "Image PhotometricInterpretation": "2", "Image ImageDescription": "The TRAPPIST-1 system contains a total of seven planets, all around the size of Earth.\u00a0Three of them -- TRAPPIST-1e, f and g -- dwell in their star\u2019s so-called \u201chabitable zone.\u201d The habitable zone, or Goldilocks zone, is a band around every star (shown here in green) where astronomers have calculated that temperatures are just right -- not too hot, not too cold -- for liquid water to pool on the surface of an Earth-like world.\u00a0\n\nWhile TRAPPIST-1b, c and d are too close to be in the system\u2019s likely habitable zone, and TRAPPIST-1h is too far away, the planets\u2019 discoverers say more optimistic scenarios could allow any or all of the planets to harbor liquid water. In particular, the strikingly small orbits of these worlds make it likely that most, if not all of them, perpetually show the same face to their star, the way our moon always shows the same face to the Earth. This would result in an extreme range of temperatures from the day to night sides, allowing for situations not factored into the traditional\u00a0habitable zone\u00a0definition. The illustrations shown for the various planets depict a range of possible scenarios of what they could look like.\n\nThe system has been revealed through observations from NASA's Spitzer Space Telescope and the ground-based TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope) telescope, as well as other ground-based observatories. The system was named for the TRAPPIST telescope.\n\nNASA's Jet Propulsion Laboratory, Pasadena, California, manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at Caltech/IPAC. Caltech manages JPL for NASA.", "Image Orientation": "Horizontal (normal)", "Image SamplesPerPixel": "3", "Image XResolution": "72", "Image YResolution": "72", "Image PlanarConfiguration": "1", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Adobe Photoshop CS6 (Macintosh)", "Image DateTime": "2017:02:21 12:47:43", "Image ExifOffset": "2160", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "2298", "Thumbnail JPEGInterchangeFormatLength": "3167", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "960", "EXIF ExifImageLength": "540"}