I love the scale that FAQs for things like this provide, as well as the variety of questions.

Q: How many objects are there in SpaceEngine?

A: The entire Hipparcos catalog of stars, all known extrasolar planets, over ten thousand galaxies, most objects in the solar system, which adds up to 130,000 things. In addition, more galaxies and star systems than exist in reality in all of the observable universe.

Q: How can a water planet be hot?

A: Water in the upper atmosphere is in the form of hot vapor, but farther down it smoothly transitions into a liquid state under high pressure. Even deeper it turns into a solid state called ice VII.

Q: How do I move?

Use WASD keys.