Millions of Earthlings looked to the sky last week to watch the moon turn a reddish-orange color as Earth passed in front of it.
Associate professor of physics Axel Mellinger took more than 700 photographs of the “blood moon,” as it’s called, with his camera during the event and then converted them into a seamless time-lapse video.
“A lunar eclipse occurs when the moon passes directly behind the Earth into its shadow,” Mellinger said. “A blood moon is a rare occurrence and does not happen each time we have a full moon. It can only occur when the sun, Earth and moon are perfectly aligned, with the Earth in the middle.”
Total eclipses occur every 2 ½ years on average, but not at regular intervals. In 2014, two total lunar eclipses were visible from Michigan, on April 18 and Oct. 8.
“The Earth’s atmosphere scatters out shorter-wavelength light such as blue and green that does not reach the moon,” Mellinger said. “Longer-wavelength light, such as red, has a higher probability of passing through the atmosphere and reaching the moon’s surface during a total eclipse, giving rise to the ‘blood moon’ appearance.”
Mellinger said that the next good viewing opportunities for a total lunar eclipse will be the nights of Sept. 27, 2015, and Jan. 20, 2019.
“An interesting thing to note is that when the moon, Earth and sun are aligned for a lunar eclipse, they also are frequently aligned for a solar eclipse two weeks before or after the lunar eclipse,” Mellinger said.
Unlike a lunar eclipse that may be viewed from anywhere on the night side of Earth, solar eclipses can only be viewed from a certain relatively small area of the world. Lunar eclipses are safe to view without any eye protection as they are dimmer than the full moon, but observers should use appropriate eye protection to safely view a solar eclipse.
“If the weather cooperates, we will be able to see a partial solar eclipse at sunset on Oct. 23,” Mellinger said.