Bungie has announced that Destiny's servers will be temporarily taken offline tomorrow, Thursday November 13th, for serveral hours as they work to prepare for additional content which will be added to the game in the coming weeks.
In an update on their website, the developer said, "The maintenance window begins around 8AM Pacific. We'll be done by (or shortly after) Noon, if all goes according to plan."
That's 16:00 to 20:00 GMT and 11:00 to 15:00 ET.
The changes being made will not require you to download a patch or update as they're happening on Bungie's side. They advise you to follow them on Twitter, or check the Bungie.net forums for information on when the update and when it ends.
You can check out our review here.