Earth had life for roughly three billion years before it produced enough oxygen to be detectable from space, which means NASA's new planet-hunting telescope could be staring directly at an inhabited world and see nothing - Space Daily

Core Impact Points

• Earth had life for roughly three billion years before producing enough oxygen to be detectable from space.
• NASA's new planet-hunting telescope may be staring directly at an inhabited world and see nothing.
• The oxygen production timeline affects the detectability of inhabited worlds from space.