Tonight, Tuesday 8 Novermber, Australia is in prime position to watch a total lunar eclipse – also known as a blood moon.
It gets its name from the coppery red colour the moon turns in the eclipse.
Lunar eclipses happen when the Moon moves into the Earth’s shadow.
With the Sun’s light blocked from reaching the Moon, it becomes illuminated only by light that’s made it through Earth’s atmosphere.
This light is mostly red because red light gets scattered least in our atmosphere – exactly the same reason sunrises and sunsets are red.
“When you look at the moon during the total lunar eclipse, you are seeing the sunrise and sunset of the Earth lighting up the moon,” summarises Dr Brad Tucker, an astrophysicist from The Australian National University (ANU).
Australia won’t see another total eclipse – where the Moon is completely red – until 2025.
In the eastern and central states, the entire total eclipse will be visible. In Western Australia, the Moon will rise after the total eclipse has started, meaning those in Perth will watch the blood moon rising.
Here’s each state and territory’s rough timing for the blood moon:
ACT/NSW/VIC/TAS: eclipse from 8:09pm – 11:49pm, total eclipse from 9:16pm – 10:41pm.
QLD: eclipse from 7:09pm – 10:49pm, total eclipse from 8:16pm – 9:41pm.
SA: eclipse from 7:43pm – 11:19pm, total eclipse from 8:46pm – 10:11pm.
NT: eclipse from 6:42pm – 10:19pm, total eclipse from 7:46pm – 9:11pm.
WA: eclipse from 6:43pm – 8:49pm, total eclipse from 6:43pm – 7:41pm.
While lunar eclipses only happen during a full moon, each full moon doesn’t bring with it a total lunar eclipse.
“This is because the moon’s orbit is not always in perfect alignment with the sun and the Earth,” explains Tucker.
“The moon wobbles by about five degrees as it orbits around the Earth. For the moon to move perfectly into Earth’s shadow, it needs to be aligned with the Earth. Sometimes it just skims the shadow and we get a partial lunar eclipse.”
Partial lunar eclipses are much more common. Solar eclipses – when the Moon is between the Sun and the Earth – are even rarer, but there will be one visible from the westernmost tip of Australia in April next year.
You’ll be able to see the blood moon with the naked eye. But if you want a particularly good look, a telescope or binoculars can help.
Indigenous people had a variety of meanings for lunar eclipses. For instance, on Mua Island in the Torres Strait, the blood moon signified an invading army. For more on First Australians’ lunar traditions, read Duane Hamacher’s and Karlie Noon’s article published by Cosmos last year.
And if you’re keen to learn more about the Moon, stay tuned for our Huh? Science Explained podcast on Thursday.