Happy Thanksgiving! We can be fairly certain that wherever humanity goes in the future, we'll carry our holidays with us. Details may change, of course. Observation of marmots or hedgehogs for signs of spring in Europe became Groundhog Day in North America. The Irish custom of carving faces in turnips at All Hallows Eve became the pumpkin jack-o-lantern in the U.S. The party hats, exploding "crackers," and plum pudding of English Christmases didn't survive the transatlantic transplantation, but Christmas trees did. We have visits from Santa Claus (aka Saint Nicholas), while children in other countries await other gift-bringing icons such as Father Christmas, Pere Noel, and the Three Kings. Modern Jewish families may light electric menorahs instead of old-fashioned candles. When we migrate to distant planets, we may decorate exotic native plants or even crystal outcroppings rather than pine trees, but we'll surely decorate something.
For poetic meditations on the holidays in an age of interstellar travel, enjoy these filk carols on Suzette Haden Elgin's blog (divided into 2 lines because the software cuts off the end when it's displayed on our blog page):