The Sun rose over Utqiagvik, the northernmost city in the United States, on Sunday and will not set again until August 2. In Utqiagvik, the Sun has now reached a point in the year where it stays above the horizon all day and all night. Normally, the Sun sets because Earth rotates and your part of the planet turns away from it. But near the Arctic, during summer, Earth is tilted toward the Sun. That tilt keeps places like Utqiagvik facing sunlight continuously. So although the Sun appears to dip very low in the sky around 1: 48- a.m., it never actually disappears below the horizon. By 2: 57- a.m., it starts climbing higher again. This means residents will have 24-hour daylight until August 2 , no true nighttime sunsets for more than two months. This natural phenomenon is known as the midnight sun.