Three Things to Know About Summer Solstice

Posted on Thu, June 21, 2018

Today is the summer solstice in the Northern Hemisphere, and the Smithsonian is celebrating all day Saturday!  At the National Air and Space Museum, we asked some visitors what the summer solstice means, and we were quite impressed with their answers.  

Confused about what a solstice is and what causes it? The National Air and Space Museum is here to help explain the celestial term.

Now that you have the basics down, here are three more things you might not know about the solstice:

  1. The solstice is the longest day of the year, but it might not be the latest sunset where you live. How can that be?  It has to do with some weirdness in the Earth’s orbit, along with how the planet’s rotation matches up with our clocks. (The good people at EarthSky have a great explanation with more detail.) You can check online charts to see when the Sun will set where you live and whether the latest time lines up with today’s solstice.
  2. There are still shadows on the solstice in most parts of the Earth. We know the Sun is the highest in the sky at midday on the summer solstice; many people think that means it will be directly overhead and we won’t see shadows at all. Unless you live close to the Earth’s equator, you will still see shadows because the Sun isn’t quite fully overhead. However, you will see the smallest shadows of the year today. (Fun game: make a paper sundial and tape it down on a windowsill. Draw a pencil mark where the shadow reaches on the solstice, and each month make a new mark at the same time of day to see how the shadow changes!)
  3. The full Moon is lowest when the Sun is highest. A full Moon is always opposite the Sun in the sky, which means that when the Sun is high in the sky (around the summer solstice) then the next full Moon will be at its lowest for the year. Thankfully, the inverse is also true: In the winter when the Sun is at its lowest above the horizon, the full Moon makes its highest path through the sky and illuminates our long nights. The next full Moon is one week from today, June 28, so look for how high it gets in your sky (it peaks at midnight). Then, compare it to the full Moon in December.

Celebrate the solstice with the Smithsonian! Find events all day on Solstice Saturday, June 23, 2018, at the National Air and Space Museum and other Smithsonian locations.

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