Life on Mars: UK researchers to study NASA mission samples © Getty Images

How to see Mars at its biggest and brightest this week

The Red Planet will be directly opposite the Sun at around 1am on Wednesday 14 October making it appear more prominent in the night sky

Skygazers may have noticed that Mars is looking bigger and brighter at the moment due to a process which only happens every two years or so.

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The event, known as “opposition” among astronomers, is when the Red Planet and the sun are on directly opposite sides of Earth.

Although people should see the planet already – it appears as a bright orange dot – it will be at its best around 1am on Wednesday 14 October, according to the Royal Observatory Greenwich.

“It’s a really good chance to view it – the last time this happened was 2018 but it was quite difficult for a lot of people to see because it was quite down in the horizon,” said Hannah Banyard, an astronomer at the Royal Observatory Greenwich.

“For about a month or so now, it’s been quite easy to see, as it’s getting close to opposition it’s rising earlier, so it rises from sunset and then you can see it and it gets up quite high into the sky, so it’s really easy to spot.”

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Opposition happens around every 26 months and is not set to occur again until 2023.

Despite cloudy weather forecast for parts of the UK, Mars should be visible among any breaks and even through lighter cloud, Ms Banyard added.

“You can see it as a bright orangey-red looking star just with your eyes, but I recommend using at least a four-inch telescope with 24-millimetre magnification and then you’ll be able to make out some features on the surface,” she said.

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“The next time you will be able to see Mars as big and bright will be 2033.”

Reader Q&A: How did Mars lose its atmosphere?

Asked by: Aseer Awsaf

Mars today has a thin atmosphere: the volume of gases (mostly carbon dioxide) in its atmosphere is less than 1 per cent that of Earth’s. However, evidence from the surface of Mars indicates that the planet was once much warmer and wetter than today. This suggests that the Martian atmosphere must once have been much thicker, creating a strong greenhouse effect that trapped the Sun’s light.

Thanks to numerous missions to the Red Planet, we now know that in its early infancy, up until around four billion years ago, Mars had a strong magnetic field, created, just like Earth’s, by convection currents of molten metals in the planet’s core. But, unlike Earth, Mars cooled enough internally to switch off this mechanism, and the planet ended up with no global magnetic field. Without this magnetic field, the planet was less protected from the solar wind – the stream of energetic charged particles flowing from the Sun.

The solar wind stripped away most of the Martian atmosphere in only a few hundred million years after the planet lost its magnetic field. This process was quick because the Sun rotated much faster in its youth, which made the solar wind more energetic. The loss of a large fraction of its atmosphere to space was a major cause of Mars’s transition from a warm, wet climate to today’s cold, dry one.

In contrast, the fact that the Earth retained its magnetic field, which deflects the solar wind, and hence held on to its atmosphere, ultimately allowed life to develop here.

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