Questions answered
THE SECRETS TO SHOOTING STARS, SUNSETS AND THE RING AROUND THE MOON REVEALED
As we head towards the end of yet another amazing year of sky events across Australia, I thought I’d share with you some of the questions readers have asked me over the past 12 months.
See how you go with answers.
What is the difference between the morning and evening star?
What many people call the morning or evening star is actually the planet Venus.
Look for it low in the south-west now at sunset as our evening star, but later in the new year it’ll be popping up before dawn, thus becoming the morning star. So, the distinction between ‘morning’ and ‘evening’ simply refers to the time at which the planet is visible. What are shooting stars? Shooting stars and falling stars are both names that people have used for ages to describe intense streaks of light across the night sky.
However, they aren’t stars. They’re caused by small bits of rock called meteors burning high in Earth’s upper atmosphere. About 19 000 meteors hit the Earth’s atmosphere every day. Why do stars twinkle? It’s an illusion. Because stars are so incredibly distant, to our eyes they appear strictly as points in the night sky. Earth’s unsteady atmosphere causes starlight to dance around, making the familiar the Q&A time: ‘twinkling’ effect. That’s all.
Why does the moon look bigger at the horizon?
This is also an illusion. When you see the moon high in the sky against the vast panorama of outer space it looks small. However, when the moon is on the horizon surrounded by trees, buildings, or distant landmarks, the bright disc of the full moon appears quite large indeed, much bigger than we would expect. Why are sunsets always red? Down low, the sun’s light comes to our eye through a thicker layer of atmosphere and this filters out all the sun’s colours except the red light.
Why is there a ring around the moon?
It isn’t really around the moon, it just looks that way. It is formed when ice crystals in our atmosphere bend the moon’s light into a circle, making that amazing ring effect. It’s usually a good sign it is going to rain and old timers say if you count the number of stars inside the ring, that’s how many days of rain you’ll get.
See if I’m wrong next time you spot one. ● David Reneke is a writer with Australasian Science magazine.