The solstice happens late Tuesday night. Here are 11 facts you may have not known about this bi-annual event:

1. It's the longest day of the year. The summer solstice gives us more than 15 and a half hours of daylight, but for our friends in the southern hemisphere, it's the first day of winter or the shortest day of the year.

2. It's the first solstice of the year, when the sun's rays are directly over the Tropic of Cancer.

3.This is the day the sun reaches its northernmost position before it starts getting lower in the sky.

4. It occurs at the same time all over the world. For us, at 11:24 p.m.

5. It can be on June 20, 21, or 22. June 22 solstices are rare -- the last one occurred in 1975, and the next one occurs in 2203!

6. It's the first day of summer. Enjoy it, because autumn is just three months away.

7. The Earth is furthest from the sun. We are closest in December.

8. The earliest sunrises and latest sunsets do not occur on this day. The sun came up few seconds earlier yesterday, and will set a few seconds later a few days from now.

9. It's not usually the hottest day of the year. That occurs in July.

10. North of the Arctic Circle, they get 24 hours of daylight!

11. It's celebrated across the world, so enjoy summer while we have it. The days start getting shorter later this week.