The Sun is 4.6 billion years old, but what did it look like in its early years?

The Sun is 4.6 billion years old, but what did it look like in its early years?
This new report states that NASA’s next mission to be to directly study Earth-like exoplanets, as we know so little about other planetary systems
This study will show how Earth-like planets are formed and what astronomers need to look for in other planetary systems
The exoplanet HD 131399Ab is unlike any other known world