Santa’s sleigh? Hmm, not quite – it will actually be a lucky glimpse of the International Space Station (ISS) as it passes over the U.K.
The ISS makes a full orbit of Earth every 92 minutes. However, each orbit covers a different area of Earth, so the people of the United Kingdom are particually lucky to have a passing of the ISS coinside with Christmas eve. The light they will see is the reflection of sunlight from the satellite's surface.
Virtual Astronomer worked out that the ISS will pass over the U.K. in the late afternoon of December 24, starting in the west of the sky at 5.19 p.m. GMT and setting in the south east at 5.26 p.m. These times will vary a bit depending on where abouts you are. Although, you should be able to find what time it will cross your path with NASA’s station spotter tool. Of course, it also helps if it's a clear night.
Among those on the 400-kilometer-high (248-mile) orbit will be Russian cosmonaut Mikhail Kornienko and American astronaut Scott Kelly, currently the record holder for the longest time in space. Don’t feel too bad for them up there, though – even they get a relaxed day with gifts, decorations and a meal of smoked turkey and dehydrated mashed potatoes. Yum, pass the thermostabilised cranberry sauce.