If you look outside as the moon is rising on Wednesday night, you may think it's, well, big. As in unusually big. As in, it grew. No need to get alarmed. It's a moon illusion. Space.com reports that the moon only seems bigger--a trick our minds play on us that make a full moon seem bigger when it's near the horizon.
Space.com senior science writer Robert Roy Britt says that even though many people swear the moon is bigger, claiming Earth's atmosphere magnifies it, it's not. "But it really is all in our minds. The moon is not bigger at the horizon than when overhead," Britt writes.
The illusion is especially noticeable when the moon is full, as it is on June 18, and perhaps at its greatest when it's a "solstice moon." The summer solstice is on June 20 in the Northern Hemisphere. NASA explains why we see this illusion: "The sun and full moon are like kids on a see-saw; when one is high, the other is low. This week's high solstice sun gives us a low, horizon-hugging moon and a strong, long-lasting version of the illusion."
