Skylight: How TRAPPIST-1’s Earth’s-sized Planets Compare to our Solar System

by Irene Pease on Jun 23, 2017 1:14 pm

TRAPPIST-1’s planets are much closer together than the planets of our solar system. See how the scale of this recently discovered system of seven planets, located about 40 light-years from Earth, compares to our own, and to Jupiter’s system of moons.

How TRAPPIST-1's Earth's-sized Planets Compare to our Solar System - Transcript SkyLight 17-03 TRAPPIST-1 text (no credits) [Titles appear, music fades up.] [A starry night sky appears.] Astronomers recently discovered seven small, rocky planets orbiting a star 40 light years from Earth. [An outlined figure marks the constellation Aquarius, the water-bearer.] The star, TRAPPIST-1, lies in the direction of Aquarius. [A ring appears marking the position of the TRAPPIST-1 system in the sky.] It is too faint to see in our night sky... [Several similar rings appear. The view begins to pan slowly to the left, showing more rings. ... as are most of the stars that host known exoplanets. [The camera continues to pan left while the sun and inner planet orbits appear. The camera begins to pull away from the Sun.] A quick trip to TRAPPIST-1 will offer a closer look at the system. [We continue traveling away from solar system, beyond the outer planet's orbits. Names of the exoplanet host stars appear next to their rings. The TRAPPIST-1 system emerges from the right side. We fly by Proxima Centauri, the nearest star and exoplanet to the Sun. TRAPPIST-1 emerges from the right and moves to the center. Names and all other rings fade off. TRAPPIST-1's ring grows, fills, and expands beyond the view. At its center, a small red dot appears and grows slightly.] Distances between the star and its orbiting planets are to scale, but we'll magnify each for a better look. [A magnification label appears, "2x", above the small red TRAPPIST-1 star. To the right of TRAPPIST-1, seven tiny dots appear along a horizontal line, and a label above them reads "5x." The dots grow in size to distinguishable images of an artist's conception of the TRAPPIST-1 planets. As they grow, the "5x" rapidly changes to "15x," "25x," "35x," "45x," "55x," and "66x" to reflect the growing planets. The words "artist's conception" appear below the planets.] How does the TRAPPIST-1 system compare with our solar system? [Our sun appears in the center of view, replacing TRAPPIST-1, and is much yellower and larger. It is labeled "1x."] [Receding from the sun and the TRAPPIST-1 planets, the magnification labels fade off, and the Sun transforms into a shining star. Mercury's orbit comes into view, and is quite large compared to the TRAPPIST-1 system.] The TRAPPIST-1 planets are much closer to their star. [View continues pulling away from sun. As orbits of Venus, Earth and Mars come into view, TRAPPIST-1 planets are lost in the glare of the sun. Jupiter's orbit comes into view. The camera pauses.] The size of the TRAPPIST-1 system is more like the orbits of Jupiter's largest moons. [The Jovian system emerges from view as the rest of the solar system fades. Shown are a tiny Jupiter, along with the Galilean moon's orbits. The seven TRAPPIST-1 planets appear in a line to the right of Jupiter, magnified 66x. The innermost planet falls within the outer orbit of Jupiter's moon, Callisto.] [Jupiter and its moon's orbits fade. An enlarged Earth and Moon appear above the left and right side of the TRAPPIST-1 planets, respectively.] Compare the Earth and the Moon at the same magnification. [Earth moves and scales down to 66x, coming to rest below the leftmost TRAPPIST-1 planet. They are nearly the same size. The Moon moves and scales down to 66x, coming to rest overlapping Earth's right side. The Earth-Moon separation is similar to the separation between the two leftmost TRAPPIST-1 planets.] Imagine seeing these neighboring worlds from one of TRAPPIST-1's planets. [Fade to black, credits begin to roll. Music fades.]