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 December nigh skies hold for the astro-curious out there, young and old.
This month I want to talk to you about planets.
Oftentimes we look into the night sky and see a dazzling array of individual points of light. Sometimes these are stars, sometimes they are meteors, even others are human made (satellites and the International Space Station are visible from Earth) but every once in a while we can actually see one of our solar system neighbours and by that I mean fellow planets.
The word planet comes from a Greek word that means 'wanderer.' This was because in ancient times these apparent stars would make their way across the night sky changing their positions daily against what would appear to be a relatively fixed backdrop of stars. Upon further inspection many of these planets were found to have other apparent stars circling around them, which were later determined to be their moons.
One such planet is Jupiter. Jupiter is massive. Like real massive. You could fit 1,300 Earths in Jupiter, it's that big. But it's also over five times the distance away from the Sun than we are which is why it isn't huge in our night sky and for all intents and purposes looks like another star. It is also quite bright ... and it's about to get a lot brighter.
On the night of Dec. 7, Jupiter will be in opposition. Opposition simply means that Earth will lie directly between the Sun and Jupiter meaning that it is the one day of the year that, from our perspective, Jupiter will be its brightest reflecting the most light from the Sun. It rises at sunset and sets at sunrise so you'll be able to see it all night long. How do you know what you're looking at is a planet and not a star? Well, a good rule of thumb is to watch for twinkling. If your light twinkles or flickers it is likely a star. If the light is steady and clear, it's likely a planet.
Now because Jupiter is in opposition you should be able to see two of its biggest moons with unaided eye as well! Ganymede and Callisto are two of the Galilean Moons of Jupiter. Now while they're moons that doesn't mean they're small. Both are close to the size of Mercury. How do you see them?
Find Jupiter in the sky then align yourself with something narrow that you can use to block Jupiter. Something like a phone pole. Get in a position such that Jupiter is blocked and you should be able to see two small star-like points of light right beside where Jupiter was. Those are the moons of Jupiter!
For more information on what nights are best and on which side of the pole you're looking at check out this month's Star Gazing Guide.
I hope you enjoy this month's Star Gazing Guide. If you want to learn more, check out the December 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.
