Is that a UFO?

One particular visitor to our night skies is often mistaken for a UFO. Astronomer Perry Vlahos explains why.

Photos: Anne Morley, NASA
July 2018


planet venus

We’re heading into peak UFO season, and here’s how to spot one!

Following sunset throughout August, look to the northwest - a little right and above the setting sun. Scan for a bright single point of light, outshining all the stars. You’ve got it? Great...

This object alone is responsible for most UFO enquiries fielded at the Astronomical Society of Victoria (ASV). To casual observers it seems to appear suddenly, catching people off guard. 

And it’s here again!

By definition, an unidentified flying object (UFO) remains so, until it’s identified. Let’s identify this one, which seems to most commonly be the culprit - planet Venus.

Almost double the size of Mars and nearly the same diameter as earth, Venus comes closer to us than any solar system planet. Because of its inner orbit to Earth, it’s not always visible, rendering its visibility to ‘seasons’ of a few months at a time. 

Furthermore, it alternates between being seen only before sunrise as the ‘morning star’, or as is the case currently, as the ‘evening star’ seen soon after sunset.

The confusion stems from Venus being out of the evening sky for many months before announcing itself in the north-west again, without fanfare. It’s the first ‘starlike’ object seen every evening, before the stars appear. Being more luminous than any other object in the night sky except the moon, it’s not easily ignored and becomes a magnet for the eyes. 

In fact, if you’re not an avid stargazer you wonder what this thing is, because it’s so bright you know it can’t be a star.

Always at its highest straight after sunset, if you look for it again an hour or two later, it’s moved closer to the horizon and lower in the sky. This can also perplex, thinking it’s moving against the stars. However due to the Earth’s constant rotation, we’ve moved along further east and it has naturally travelled further west.

If you’re after positive identification, on the evenings of 14 and 15 August, the moon will be very near to it, and a beautiful sight to behold. Don't miss it. And get the camera out too.