It's time for Destiny's servers to be reset and to usher in a new week.
Bungie has reset the Destiny servers. Your marks cap has removed, and the new Nightfall and Heroic strikes have gone live.
This week's strike is the Winter's Run. Rainbow burn is back for the Nightfall, meaning you and the enemy do more damage with any elemental attacks. That's Arc, Solar, and Void.
The Heroic only has Void burn though.