Happy summer! Today is the Summer Solstice, our hemisphere’s longest day. Our Earth has seasons because its axis is tipped about 23 degrees, in other words it isn’t straight up and down. As the Earth orbits the Sun, the tilt causes us to experience seasons. In the United States, we have summer when the northern hemisphere is tilting towards the Sun. The summer solstice itself is the day when the axis is tilted most towards the Sun. From the ground, we can see that the Sun takes the highest path across the sky, and we experience the year’s longest day and shortest night. As the Earth continues in its orbit, the axis will slowly tilt away from the Sun. Little by little, we will see the Sun take a lower path across the sky and the days get shorter. Once the Earth has reached the opposite side of the Sun, its axis is tilted away and we experience winter. What’s happening in the Southern hemisphere during all of this? Exactly the opposite! They are having their Winter Solstice today.