Mars, our second closest cosmic cousin, has been in our collective imagination for decades. Between fantasies of martian visits and the promise of water under its icy surface, Mars doesn’t need to do much to be in our collective good books.
But very soon, Mars is not just going to be close to our hearts, but also nearest to our actual planet – a mere 62.1 million kilometres (38.6 million miles) away from Earth.
This is the closest it’ll be for the next 15 years. And it means that stargazing is highly recommended as Mars will be bright, big and easy to see with or without a telescope.
We’d recommend checking out a sky chart to work out where Mars will be in the night sky in your location so you can plan for the best viewing.
But the good news is, it’ll be in a region of the night sky with very few stars, and if you’re lucky, you should also be able to catch Jupiter and Saturn shining brightly closer to the horizon.
The day we’ll be the absolute closest to Mars is the 6 October, so get a move on.
As you can see in this video below, Mars and Earth are both on slightly elliptical orbits, which means they can occasionally get very close to each other.
The closest possible encounter is when Earth is the furthest away from the Sun (aphelion) and Mars is the closest to the Sun (perihelion). At this point the two would be at the minimum 54.6 million kilometres (33.9 million miles) apart.
This configuration is called an opposition, and it happens every two years or so. But we’ve never actually recorded us hitting that perfect ‘closest’ point.
The closest approach we’ve ever recorded happened back in 2003, with just 55.7 million kilometres separating us with Mars. Two years ago, 2018 was pretty close too, with just 57.6 million kilometres (35.8 million miles) between us.
Unfortunately though, we’re getting further and further out of alignment with our closest neighbour and won’t start getting closer again until 2029, culminating in a very close approach in 2035 – only 56.9 million kilometres (35.4 million miles) apart – so start planning your 2035 Mars watching schedule well in advance!
At the other end of the scale from an opposition is a conjunction, when the two planets are furthest from each other. They can end up a 401 million kilometres (250 miles) away from each other. This occurs when Earth and Mars are on opposite sides of the Sun and both in their aphelion.
It’s for this reason that space organisations take advantage of the short distance between our planets when these windows arise. This year was a peak opportunity for many missions to the Red Planet.
But three missions did successfully take off. NASA’s Perseverance rover is close to half way through its journey to the red planet after blasting off back in July, while two other missions left for Mars in the same two-week window.
The next lot of Mars missions – like the Mars Sample Return – will be travelling in 2022, but they’ll have to travel an extra 20 million kilometres, as we’ll be at a distance of 81.5 million kilometres (50.6 million miles) at our closest approach during this time.
So this week is a pretty special opportunity that we won’t have again until 2035. Make sure you wave to Mars as it goes past!