I was thinking of potential planet explorations, by extremely advanced alien species, through automated drones (or "flying laboratories") scanning and analyzing the planets. (By "extremely advanced", i mean they lived for millions or billions of years, mastered every possible laws of physics, can manipulate and use antimatter and whatever other matter we don't really know exists like dark matter, exotic particles ... and travel through space via wormholes)
I came to a point where analyzing the crust and and core of a planet would be a problem. With today's technology, I read we can't drill deeper than what we actually drilled (~12km) because of the high temperature and the "toughness" of the rock.
The drones can fly in stationary, are really numerous (millions per planets), has very high energy autonomy (like, fusion battery) and resist to high temperature and pressure thanks to technologies we don't know yet (a.k.a. "protection shields"). They are not conveniently perfect. I know I say they are extremely advanced, but I guess we can't just throw those drones into the sun, because of certain laws of physics (magnetism, dangerous "rays", >1,000,000 C°...)
Then, with this alien technology, would it be possible to "vaporize" the rocks with an extremely hot laser beam to "drill" to the core (at least the liquid part of the core to "swim" in) ? If not (rock collapsing ?) what could actually help to dig to the core ? nanotechnology ? cooling the core of the planet ?... (consider you have unlimited resource and energy, not infinite but in very large amount)
For the sake of the story (and the whys) : these aliens are so advanced in everything, the last thing they don't know is "what is the universe looking like ?", so they decided to analyze every single planet, stars and "objects" of the universe, looking for resources (to make more drones, "refuel" ships etc...) and for signs of life. They are pacifists (they don't need to conquer anything), respect planets with life and let it develop (but they still analyze it)...
thanks for your answers, or whatever comment you post to help me resolve this tiny problem.