Q: Does the sun in Alaska shine in the same place once every six months? I want to know why in December is the shortest daylight hours and in June the longest daylight hours. Is this the way we travel around the sun?
—Robert Hand, Stockbridge
A: Because the Earth's axis is tilted 23.5 degrees, the North Pole of Earth is tilted toward the sun in June—our summertime—while the southern hemisphere is tilted away from the sun, Mark Lancaster, an astronomer at Fernbank Science Center, told Q&A on the News. As a result, our summer is their winter.
“As the Earth orbits the sun, six months later just the opposite occurs, as the southern hemisphere is pointed towards the sun and the northern hemisphere is pointed away from the sun,” he wrote.
The sun’s altitude is higher in the summertime, leading to more daylight hours. For example, in Anchorage, Alaska, the Sun on June 20 will get to about 52 degrees above the horizon (straight overhead being 90 percent) but on Dec. 20, the sun will barely get to 5 degrees above the horizon.
“At the North Pole in winter, the sun won’t get above the horizon at all for a period of time, while at the South Pole the sun doesn’t set for that same period of time,” he wrote.
Fast Copy News Service wrote this column; Do you have a question? We’ll try to get the answer. Call 404-222-2002 or email q&a@ajc.com (include name, phone and city).
About the Author