TESS

TESS stands for the Transiting Exoplanet Survey Satellite, a NASA space telescope launched in 2018 designed to discover planets orbiting distant stars. Unlike traditional telescopes that take pictures of space, TESS monitors the brightness of thousands of stars simultaneously, looking for tiny dips in light that occur when planets pass in front of their host stars. These brightness dips, called transits, reveal the presence of exoplanets and provide crucial information about their size, orbital period, and potential habitability. TESS has become one of the most prolific planet-hunting missions in history, discovering thousands of confirmed and candidate exoplanets.

TESS operates at the intersection of astronomy and planetary science, contributing to our understanding of planetary systems across the galaxy. The mission is used by thousands of astronomers worldwide who analyze TESS data to identify and characterize new worlds, search for potentially habitable planets, and study the diversity of planetary architectures. This work matters because it addresses fundamental questions about how common planets are, whether Earth-like worlds exist elsewhere, and how planetary systems form and evolve. TESS data also enables follow-up observations by other telescopes, including the James Webb Space Telescope, creating a collaborative network of discovery.

TESS works by measuring the brightness of stars with extraordinary precision, detecting the tiny shadows cast by orbiting planets. Imagine watching a city's streetlights from an airplane at night: if you saw one light dim slightly and regularly as something passed in front of it, you'd know an object was moving across it, even if you couldn't see the object directly. TESS divides the sky into sectors and observes each region for approximately 27 days, collecting data every 30 minutes for about 200,000 nearby stars. This relentless monitoring allows the satellite to catch planets at different orbital positions and confirm their existence through multiple transit observations.

TESS is reshaping exoplanet science by providing an unprecedented census of planetary systems in our cosmic neighborhood, enabling researchers to understand how common various types of planets are. The mission has already revealed unexpected planetary diversity—from ultra-short-period planets orbiting their stars in just hours to potential Earth-sized worlds in habitable zones—fundamentally changing our models of planetary formation. With its continuing operations and years of data yet to be analyzed, TESS promises to identify the prime targets for future atmospheric studies and the search for signs of life beyond Earth.