Planets beyond our solar system


The Spitzer Space Telescope, launched in 2003, is on a mission to become NASA’s first infrared light observatory. It gave astronomers an unprecedented infrared view of the universe, allowing us to peer into regions of space hidden from optical telescopes with unprecedented clarity and sensitivity. One of NASA’s great observatories, Spitzer discovered a ring of Saturn, studied some of the most distant galaxies, and identified two of the most distant supermassive black holes ever discovered, among other accomplishments during its 16 years of operation.

The study of exoplanets – planets outside of our solar system – was not one of Spitzer’s original goals. But innovations during his mission improved Spitzer’s accuracy and allowed him to become an essential tool for work on exoplanets. Spitzer marked a new era in planetary science by being the first telescope to directly detect light from exoplanets. He has played a key scientific role in everything from planets larger than Jupiter to small, rocky worlds that can be Earth-like.

In 2017, Spitzer helped reveal TRAPPIST-1, the first known system of seven Earth-sized planets. The discovery set a new record for the most habitable zone planets found around a single star outside of our solar system. Spitzer’s data also showed that all of these planets are likely rocky. The TRAPPIST-1 study takes scientists one step closer to answering the question “Are we alone?”

This poster depicts the TRAPPIST-1 planets, some of which were discovered by Spitzer. The physical characteristics of the planets are currently not known, beyond their mass and their distance from the star TRAPPIST-1, which is visualized in the background. The James Webb Space Telescope should teach us more about this fascinating system.


Arline J. Mercier

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