Imagine:
You are a member of an alien species, uncomparable to most living things on Earth, and living on an arid planet, around country sized oases. During your version of the 1800's your star catches the rogue planet Earth and its moon with it. This icy desolate planet arrived after being pulled out of it's system by another star that went through the outer regions of the heliosphere of the Sun. It's arrival doesn't interrupt your star system, the most it causes are colder winters and warmer summers and marvelous meteor showers. You live in a time period similar to that of our post WW2 era, and your species has studied the orbit and properties of this planet, mostly neglecting the moon for not having anything outstanding. Getting to it will be tricky, because it's new orbit is highly elliptic, with an inclination between 45° and 50°, and the planet's surface completely freezes when reaching its apoapsis. When approaching periapsis, Earth rapidly heats up and spews it's frozen atmosphere into space like a comet until reaching it, so you have a very short amount of time to reach it in one piece, then come back... in one piece.
Earth is in the neighborhood of this alien planet. The star system, with every planet at it's periapsis (not to scale):
Star - small planet - gas dwarf with moon - dwarf planet - Alien planet - Earth with Moon - gas giant - rocky planet - ice giant.
Most of the other planets have almost circular orbits and less inclination than 10°.
But why would you go there?
Because astronomers of your kind discovered a global infrastructure on the temperamental planet, buried under (now melting and refreezing) ice, that must have been constructed by a civilization. And with a civilization comes resources and research. Your species sets a common, non obligatory goal, that is to analyse the solar intruder closer, and help sustain ourselves further with these discoveries and resources gathered from it.
The question is: What could they learn of us from the remnants that have been eroding since Earth's arrival?