Spin - Robert Charles Wilson

One night when he was 10, Tyler stood in his backyard and watched the stars go out. They flared into brilliance, then disappeared, replaced by an empty black barrier. He and his best friends, Jason and Diane Lawton, had seen what became known as the Big Blackout. It would shape their lives.
The "sun" is now a featureless disk - a heat source, rather than an astronomical object. The moon is gone, but tides remain. The world's artificial satellites have fallen out of orbit. Eventually, space probes reveal that the barrier is artificial, generated by huge alien artifacts. Time passes faster outside the barrier - more than a hundred million years per day on Earth. At this rate, the death of the sun is only about forty years away.
Jason, now a promising young scientist, devotes his life to working against this slow-moving apocalypse. Diane throws herself into hedonism, marrying a sinister cult leader who's forged a religion out of the fears of the masses.
Earth sends terraforming machines, then humans, to Mars...and immediately an emissary returns with thousands of stories about the settling of Mars. Then an identical barrier appears around Mars.
Life on Earth is about to get much, much stranger.