How would you know which one is the dad otherwise

Yup that's more like it! Awesome set btw

Okay so now I'm not so sure about which is which but here's my best guess (written on your photo).

Also, is it possible to put these keycaps "upside down" ? (so no steeper edge according to the rows) Because "Earth" sure looks rotated. That's 100% Earth, it's South America. Jupiter is upside down, Uranus needs a 90 degree rotation. The other designs are a bit confusing, like "Neptune" can be "Venus" as well considering that these planets both look "cloudy"... And if that really is Voyager 1, then it should be the last one because it already left the solar system. And I'm not sure about Pluto either because it's not a planet anymore but then we'd have 1 extra cap so I guess it's back haha

Correct order would look like this:

Sun Mercury Venus Earth (Moon?) Mars Jupiter Saturn Uranus Neptune (Pluto?) Voyager

Edit: Forgot to attach the photo lol

https://preview.redd.it/9q2cnu0cx11a1.jpeg?width=4032&format=pjpg&auto=webp&v=enabled&s=203bb48bb6b952a3f5e6bef82e1714c2f5a5a2d4

Your planets are not in order bro and it drives me crazy lol