Not sure where 20M l.y. are coming from, because the farthest exoplaned seems to be 27k l.y. from the Sun: https://en.wikipedia.org/wiki/SWEEPS-11 https://en.wi

Not sure where 20M l.y. are coming from, because the farthest exoplaned seems to be 27k l.y. from the Sun: https://en.wikipedia.org/wiki/SWEEPS-11 https://en.wikipedia.org/wiki/SWEEPS-11 Regarding your question, perhaps it's harder to perform direct imaging of a planet in the solar system than of an exoplanet against its local star(s). In the first case, relative motion is much higher.