The best alternatives to Solar Idle are ION, Out There, and 8Planets. If these 3 options don't work for you, we've listed a few more alternatives below.
What do you think of Solar Idle?
Notion— Get over $6,000 worth of Notion + unlimited AI, for free
8Planets helps you discover how the planets aligned and move around over time so that you feel the scale of the Solar System. By giving you quick and easy access to the Solar System everywhere, 8Planets will make you feel that the Solar System is close to us.
Flee Earth is a game where you control a UFO that’s escaping Earth. Watch out for the incoming asteroids! Clicking the screen will move the UFO either left or right. The game becomes more challenging as you progress. Good luck, and godspeed.
Help Manohar, our teenage alien, to survive in space on his quest to explore the rogue planets. ★ Beware of the guided missiles ★ Collect ORB to gain a shield ★ Collect LIGHTNING to Zap all incoming threats ★ Collect stars to increase your score