Question

I used to think that I'm important
But now people tell me I'm not.
I can't even control where I'm going.
But I'm quite sure that it's not hot.
I cut in front of other shapes,
Going towards the light.
Now tell me, who am I?
While I wait in everlasting night.

Answer 1

I am the planet Pluto,
The only one.
At the edge of our system,
Far from the sun.

Lines 1 and 2 are from that Pluto used to be considered a planet, but then was changed to a dwarf planet.

Lines 3 and 4 are from that Pluto can't change where it goes, and that it is far from the sun.

Lines 5 and 6 are from that Pluto's orbit cuts closer to the sun than Neptune for a while, before going back to the outside.

Line 7 is from that Pluto is so far away from the sun that even the day on the planet feels like night, and so night lasts forever.