Some three billion years ago, Mars is believed to have been a water world just like Earth. It possessed great oceans and was most likely on its way to forming life in one form or another.

Water is made up of hydrogen – the most common element in the universe – and oxygen, the third most common element. Water is extremely important to the development and sustaining of life as we know it.

Because Mars is half the size of the Earth, the planet lost its heat faster as its internal core stopped rotating. Similar to Earth’s core, which produces a magnetic field around our planet, Mar’s core ceased producing its protective magnetic field, thus allowing the solar winds to eat away at its atmosphere. Thus, the red planet lost its water.

Ever since the early telescopic observations made in 1877 by the Italian astronomer Giovanni Schiaparelli, when Mars was in opposition, residing 56-million-kilometres away, he is said to have seen “canali”, or channels, on Mars. Seeing these features gave the impression of a possible civilization. Since then, the red planet has been the focus of searching for ancient life and is also the setting for science fiction writers and movie makers.

By the 2030s or 2040s, humans are expected to land on this fascinating world, looking for the possibility of life that might have once existed, even at the microbial level. After all, life is life.

But Mars is in the news again these days for other reasons – it is now a very visible object in the night sky.

Appearing as a bright-orange object, rising in the northeast sky, about 45 minutes after the sun sets in the west, Mars is nicely placed amongst the bright winter constellations, including Orion the Hunter and Taurus the Bull. If you are still not sure where to look, any smartphone astronomy app will guide you.

So why is it so bright? Earth orbits the Sun in 365 days, whereas Mars does so in 687 days. Just like the inner lap on a race track, Earth catches up and overtakes slower Mars every 26 months. This upcoming opposition will occur on December 8, at a separation of only 82 million kilometres.

Over the weeks after opposition, our distance increases and Mars will slowly fade. Every seventh opposition is super close, such as back in 2003 and 2020. The next opposition occurs on January 15, 2025.

Be sure to look at Mars on the evening of December 7, as the Full Cold Moon will cover Mars for a little less than one hour. All of Canada, as well as much of the United States, except for Alaska and the Southeastern states, will see this amazing sight. In the Ottawa-Montréal area, Mars will begin to disappear around 10:35 p.m. and reappear around 11:25 p.m. on the night of December 7. 

Throughout its 29.5-day orbit around the Earth, the moon moves its width every hour. Throughout the month, it covers stars and in rare events, bright planets. This should be a fantastic photo opportunity, as the disappearance and later reappearance should be quite evident.

Clear skies,

Known as “The Backyard Astronomer”, Gary Boyle is an astronomy educator, guest speaker, monthly columnist for the Royal Astronomical Society of Canada as well as a STEM educator. He has been interviewed on more than 55 Canadian radio stations as well as television across Canada and the U.S. In recognition of his public outreach in astronomy, the International Astronomical Union has honoured him with the naming of Asteroid (22406) Garyboyle. Follow him on Twitter: @astroeducator, Facebook and his website: