I'm trying to find a book I read in grade school roughly 15 years ago. It probably was aimed at middle school/teens. I only remember small details from it. The cover was in that painted pulp fiction style and it probably was from the '90s. I believe it had two siblings, a brother and a sister on the cover, running from something. In the background there was a planet with colorful rings in the sky.
I remember a couple scenes from it. One was something about the Sun going out, and I specifically remember the characters talking about how long it takes for the light, or lack thereof, to reach Earth. I feel like they were not on Earth at the time, maybe on the Moon or Mars. Another smaller detail I remember is that the protagonist noticed a Mac computer, but instead of the normal Apple logo, it was either another fruit, or an apple with no bite taken out of it.
That's all I can remember. I read it in a small school library no later than 2008 or 2009.