Today is the first day of summer, and we couldn't be more excited! We have a lot of incredible things at the Science Center headed our way. On June 30, our popular outdoor exhibitions reopen for the season – Dino Dig and Wildlife Challenge – as well as our new premium exhibition, Grossology.

But today, June 21, is the summer solstice, and that's what on our minds right now! This astronomical event happens every year, but what exactly is it and why does it happen?

Many of us think of the summer solstice as an entire day, but it is actually a single moment in time – the time when the North Pole of the Earth is pointed most directly at the Sun. For those of us on the Northern Hemisphere, that happened at 6:07 am this morning.

The day of the summer solstice, though, is the longest day of the year, and the day in which the Sun will be the highest in the sky for the year.

Why do we experience the summer solstice? It's the same reason we experience seasons – the tilt of the Earth. The Earth is at a 23.5-degree tilt, and so in the summer, that tilt points the Northern Hemisphere toward the Sun (while in the South Hemisphere, it's pointed away from the Sun). Six months later, it's the opposite.