Each month, we share a Star Gazing Guide presented and organized by The Great Orbax, a science communicator from the University of Guelph's department of physics and local science education advocate.
Greetings Star Gazers!
I'm a science communicator from the department of physics at the University of Guelph and I'm here to fill you in on what our March night skies hold for the astro-curious out there, young and old.
Our big story this month is the upcoming lunar eclipse. Late on the evening of March 13 into the early hours of March 14 we'll be experiencing our first total lunar eclipse since November 2022. Since then we've had some partial lunar eclipses but what's likely the most captivating thing about the total lunar eclipse is that our full moon that night will turn red, hence the moniker of blood moon.
How is this possible and why is it so much different than the solar eclipse?
Well, when it comes down to it's all about light and shadow. When we experience a solar eclipse, the moon gets directly between the sun and our view of it from down here on earth. The diameter of our moon is 400 times smaller than the diameter of our sun but it just so happens that the sun is also 400 times further away from us. As a result, our sun and moon appear to be about the same size in the sky and therefore it's possible for the moon to fully block our view of the sun. This doesn't happen on other planets where the moons are much bigger or smaller or whose orbits are different than ours. It's weird and neat and I kind of love it.
Now with a lunar eclipse the earth gets directly between the moon and the sun and therefore the shadow of our great big spinning globe gets cast onto the tiny full moon. So, WE actually block the sun's light from reaching the moon and therefore we'd expect it to dim and disappear from our view, right?
But here's the thing, we don't actually block all the light, we redirect some of it.
The earth's atmosphere kind of acts like a prism, and when the sun's rays pass through it they bend or scatter. Short wavelength light, like blue light gets bent away from the moon and fires past into space. Long wavelength light, such as red light, actually bends in towards the moon and in fact if you were actually standing on the surface of the moon, assuming you were wearing protective equipment and had a solid supply of air being pumped into your hopefully closed helmet, you would see a red ring of light emanating around the earth.
Want to know more about the lunar eclipse and when it's happening? Well I suggest you check out this month's Star Gazing Guide video on the Guelph Physics YouTube channel. Not only is Star Gazing a great way to learn about space, planets and the stars but it's also a great way to spend time with other curious minds.
Until next month I wish you clear skies and I hope you take some time ... to look up.
