Niribu

Does not show up on your HUD if you are not near it. Gives you Super Solar Panels.

(below is an edit by Voraz, hopefully it is allowed. if not, I promise i havent touched anything above this)

Finding Niribu is often pretty difficult. It orbits the sun on an orbit that is between earth's "orbit" (earth is stationary in glap, so imagine an orbit passing through earth's location) and Mar's orbit. Niribu passes close enough to the earth that it's gravitational field overlaps with the moon's gravitational field if the moon happens to be east of the earth. In that case, there is a visible overlap similar to a Venn Diagram, but Niribu overrides the moon's gravity here.

Strategies for finding Niribu include:

Encountering it as you fly to other planets (if you do, it is really important you remember where)

Trying to travel in a circle around the sun about where its orbital radius is. This is hard, because you are beyond 500 units away from the sun if you're doing it right, so keeping constant distance is hard. Try flying east of the earth to about twice as far away from the earth as the moon's orbit, then look at the sun beacon. Though the sun's distance reading is out of range, the size of the sun beacon at this range will decrease the further you get from the sun, and its size will increase as you get closer. Circle the solar system, keeping the beacon right about that size. It will be hard, and a fast, maneuverable ship is pretty much required if you're gonna find it in a practical length of time.

Ask another player in the lobby where it is. Most likely, they wont know (generally, dont ask people who are using only the regular solar panel), but sometimes you get lucky and find a player that recently went to or flew by Niribu.

And, no, even though the wiki says that this planet will collide with earth, it pretty much always does a close flyby.