Louisa saw that Beezus kept giving her that weird look. She opened her mouth to ask about this but the professor talked and all chances of letting the girl spill it out vanished.

....

What? They were supposed to know what kind of land Mercury has from here? Far far away from the unshiny dot? Louisa frowned, confused, and took a long stare through her telescope again.

Pulling away from the stargazing tool she raised her hand, "I think the only thing I can get about Mercury without reading encyclopedias is that it has no natural satellites." Nope, she didn't see any rings revolving around the dot. "I think, though, that due to its closeness to the sun, that it has exploding holes in its land - volcanoes they're called maybe?" She really didn't know that much about planets.

Nodding her head and raising her hand once again, Louisa told the story she knew, "Yes, sir. The ancient Greeks called Mercury different names. They called it Apollo when it was visible in the morning sky, and Hermes when it showed up in the evening. Eventually, their astronomers became aware of the fact that Apollo and Hermes were actually one planet. The Romans were the ones to call it 'Mercury' after their god who was believed to be swift-footed one - they saw Mercury to be just as swift-footed as that god and the name was shared between the two." Which was quite weird and funny now that she thought of it. And that was all the ancient stuff she knew about the unshiny dot.