If you’re up early tomorrow morning and the skies are clear, there is a special sight in the sky for you.
By themselves, a lunar eclipse, a supermoon and a blue moon aren’t that uncommon. But it’s rare for all three to happen at the same time, like they will tomorrow when the lunar eclipse starts at about 2 a.m.
Lunar eclipses happen, on average, about every six months somewhere on Earth according to Sally Kilburg, South Okanagan vice-president for the Okanagan chapter of the Royal Astronomical Society of Canada.
A blue moon, the second full moon in a month, isn’t quite as common, but is still a regular occurrence, as is a supermoon, marking the point when the moon is closest to Earth in its elliptical orbit.
Having all three happening together is anything but regular.
“I don’t know of another instance. I would have to go digging through astronomical information to see if there is anything else out there,” said Ken Tapping, an astronomer with the Dominion Radio Astrophysical Observatory near Penticton.
While the moon may look a bit larger because of its closeness to the earth, the most dramatic change will be its colour, shifting to red and orange hues, which give rise to the “blood moon” nickname for a lunar eclipse.
With the earth blocking the light falling on the moon, you might expect it to vanish into the darkness. Tapping explains the moon is being lit by light refracted by the Earth’s atmosphere acting like a lens, bending sunlight and lighting the moon.
“But of course this light is going through thousands of kilometres of the Earth’s atmosphere,” said Tapping. Like a sunset, only the longer red and orange wavelengths are making it through the atmosphere to fall on the moon.
“It’s a beautiful thing, the moon turns different colours. To my eye the moon looks more like a sphere in a lunar eclipse,” said Kilburg, adding that unlike the solar eclipse last summer, lunar eclipses can be observed from a wide area.
“A lunar eclipse is something that is quite broad, it’s the shadow of the Earth falling on the moon,” said Kilburg. “We are looking at our own shadow — it’s a pretty big shadow compared to the moon.”
Tapping said one of the things that would have struck us very early on in human history was the regularity of the objects in the sky, creating the awe and fascination that continues to the present.
“The sun rises every day and the moon goes through its phases and even back thousands of years B.C., people could predict eclipses of the sun,” said Tapping. “Here on earth, everything was very uncertain. Sometimes the rain came, sometimes it didn’t. You couldn’t predict when thousands of men with sharp sticks were going to appear over the crest of a hill.
“Yet in the sky, the rhythm, unchanging, perfect all the time. I think this is the beginning of people seeing perfection in the heavens, compared with the Earth. So what went on in the heavens became important.”
Tapping said that history is one of the things he loves about astronomy.
“You look at the sky, you see the constellations, the memories of our mythology,” said Tapping. “A lot of the stars have Arabic names, some have Latin names, some have more modern names — we have been writing our culture and history in the sky for thousands of years.”
For those wanting to observe this special event, the moon starts to move into the Earth’s outer shadow at 2:51 a.m. on Jan. 31, which is when Tapping said you will first notice some darkening. Then at 3:48 a.m., you will see the real shadow of the earth start to cross the moon and by 4:51 a.m., the moon will be completely covered. By 6:07 a.m you will see the Earth’s shadow start to move off the moon and at 7:11, that will be over.
“This is a relatively long total lunar eclipse, with totality lasting for 1 hour, 16 minutes,” said Kilburg. “The entire event from the first hint of our penumbral shadow on the face of the moon till the last whisp of penumbra is about 5 hours, 17 minutes.”
For those who can’t see the eclipse due to cloud cover, you’ll still be able to watch online. NASA, the U.S. space agency, will be broadcasting live coverage on their stream.
NASAstream
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