NASA, ESA, L. Calçada
Echoes can reveal the unseen. Similar to how a killer whale can “see” through pitch-black water by bouncing high-frequency sound waves off objects, we could use light to discover exoplanets.
Whenever a star emits a bright flare of radiation, some of its light may reach Earth where astronomers will measure a burst of brightness – but the display isn’t over. Because the light emanates in all directions, it will also head towards any circling exoplanets. Once it reaches a planet, it will reflect off it and could potentially bounce towards Earth, producing a second – albeit fainter – burst, like an echo.
Though such light echoes have often been observed from supernovae, William Sparks of the Space Telescope Science Institute in Baltimore, Maryland, and his colleagues argue that such a signal could be used