Metro Detroiters can enjoy some early morning lunacy on Jan. 31. Astronomers are calling it the “super blue blood moon.”
So what does that mean?
WDET’s Pat Batcheller turned to Paulette Epstein of the Michigan Science Center in Detroit. She’s the staff astronomer there, as well as the education and theaters manager. She says three things are happening at once: a supermoon, a “blue” moon, and a “blood” moon.
“A supermoon is when the moon is closer to us than it is at other times of the year,” Epstein says. When the moon reaches this point—the scientific term is perigee—it appears slightly bigger. But Epstein says the effect is barely noticeable.
“It’s not super visible to the unaided eye, but it does get a little bit larger.”
Because the moon will be close to the horizon, it will appear larger due to the bending of sunlight. It will also be entering the earth’s shadow at 6:48 a.m., giving us a view of a partial lunar eclipse, or “blood” moon. Epstein says the term comes from the color of the moon during the eclipse.
“As the moon goes into the earth’s shadow, there is still some sunlight that gets bent through our atmosphere,” Epstein says. “So that red light is actually projected onto the moon.”
So, that explains the “blood” moon. But if it looks red, what’s a “blue” moon? It’s what happens when a given month has two full moons.
“We already had a full moon in the month of January,” Epstein says. “And because it’s happening on the 31st, we won’t have a full moon at all in the month of February.” The next full moon happens on March 1.
While we often hear the word “rare” used to describe these events, none of them are uncommon, celestially speaking. Another blue moon occurs on March 31st, giving us two this year. Lunar eclipses happen on average about once every 18 months. And supermoons come whenever the moon reaches perigee—whether it’s full nor not.
But when all three happen at once, it is truly a once-in-a-lifetime event.
“It hasn’t happened for about 154 years, and it won’t happen again for about that long,” Epstein says.
If you have a clear view of the horizon, you’ll have the best chance of seeing the super blue blood moon. But will the weather cooperate? The National Weather Service says skies over Metro Detroit should be partly cloudy around 7 a.m. on the 31st, just as the partial eclipse is happening.
Click on the audio player to hear the conversation.