Detecting an Earth-like planet presents a significant challenge due to the fact that the planet is approximately 10 billion times fainter than its parent star. This requires the use of a coronagraph to block almost all of the star’s light in order to capture the faint light reflected from the planet. However, any instability in the telescope’s optics, such as misalignment between mirrors or a change in the mirror’s shape, can lead to leakage of starlight and cause glare that masks the planet.
To overcome this challenge, scientists must achieve exceptional control over both the telescope and the instrument’s optical quality, or wavefront, to a level of 10s of picometers (pm). This is roughly on the order of the size of a hydrogen atom, emphasizing the extraordinary precision needed for this endeavor. Despite these challenges, researchers are working tirelessly to develop new technologies and techniques to detect Earth-like planets and uncover more about our universe.
In summary, detecting an Earth-like planet using a coronagraph requires precise control over both the telescope and its optical quality at an exceptional level. This level of precision is necessary to capture faint light reflected from planets that are 10 billion times fainter than their parent stars. With advances in technology and techniques, scientists hope to one day discover more about our universe by detecting these elusive planets.