NASA's TESS Found a Planet 40,000 Light Years Away...It Shouldn't Have Seen It

NASA’s TESS mission has identified Gaia23bra b, a super-Jupiter nearly 40,000 light-years from Earth—far beyond TESS’s normal search range of about 150 light-years. The planet is approximately 1.6 times Jupiter’s mass and orbits an orange dwarf star at a distance comparable to Jupiter’s orbit around the Sun. TESS usually discovers nearby worlds when they transit their stars. But Gaia23bra b was revealed through gravitational microlensing, when the gravity of a foreground system warped space-time and magnified a more distant star. Gaia first flagged the brightening event in 2023, while archived TESS observations captured the detailed light-curve features that exposed the planet. In this documentary, we explain how TESS detected a planet it was never designed to find, why microlensing events cannot be repeated, and how many similar worlds may still be hiding inside old TESS data. Could TESS’s archive contain an undiscovered population of distant planets?