News World Seven Earth-sized planets ‘too hostile’ for human life
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Seven Earth-sized planets ‘too hostile’ for human life

Earth-sized planets
An artist's concept of what it would be like to stand on the surface of the exoplanet TRAPPIST-1f. Photo: NASA graphic
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Astronomers have found at least seven Earth-sized planets orbiting the same star 40 light-years away, but experts say we should temper our excitement about the historic discovery.

The findings published in the journal Nature on Wednesday, reported the worlds could have liquid water on their surface – and potentially be capable of inhabiting life.

However, for Australian Astronomical Observatory’s Dr Stuart Ryder, several key factors aren’t included in the report that would make life extremely difficult on such planets, especially for humans.

Watch more on on the Earth-sized discovery below:

“What are the odds life could evolve there and survive? Not terribly good when you think about how hostile of an environment it is,” Dr Ryder told The New Daily.

The particular star the planets closely orbit is called a red dwarf star, which is only 10 per cent of the size of our sun, and the planets’ close proximity to the sun – not including possible freezing temperatures – would be problematic for human life.

“One of the things these dwarf stars do a lot is – like our own sun – they sometimes have these large, powerful flares of high energy particles, and if the planets don’t have any kind of atmosphere or magnetic field to protect them, then these flares are like being blasted by an x-ray machine four times a day. It’s a very good way to sterilise a planet,” he said.

“Something we need to recognise is that these very small stars can be quite unstable. So living on (the planets) could be extremely difficult, not just for us but even for microbes.”

And even if the planets found around TRAPPIST-1 were inhabitable by humans, we wouldn’t live long enough as a species to enjoy them.

“It would take 100 years essentially just to reach it,” Dr Ryder said.

“And if it was to relay information back to us at the speed of light that would take another 40 years for it to come back to us.

“We are talking from the time you launch it to the time anyone gets any information back it would be at least a century, probably closer to two.

“If people wanted to travel all that way, and even if they could it might take starships, and the first generation of people wouldn’t live long enough to get to the destination.”

We still have plenty to learn

Dr Ryder agreed the discovery was a significant outcome for astronomers, but to call the planets “Earth-like” would be a stretch.

“I’m a bit concerned when people refer to these as ‘Earth-like planets’; all we know so far is they’re rocky and dense,” he said.

NASA trappist-1f system planets
A comparison of the TRAPPIST-1 system to our solar system. Photo: NASA graphic

“We shouldn’t fool ourselves into thinking straight away that every one of these is immediately the most like Earth.

“Nevertheless compared to 20 years ago we didn’t even know there were planets around other stars, now we are finding thousands of them and it’s pretty exciting.”

Dr Ryder said we have the potential within the next decade to learn a lot more about the characteristics of each of these seven new worlds with the opening of the James Webb Telescope in 2018 – which will help answer questions about the planets’ atmosphere, vegetation, oxygen levels and whether there are signs of water.

“Compared to how far away they are it’s amazing how much we can learn from the light coming from the planet,” he said.

“Hopefully within a decade we will have the capabilities to determine the characteristics of these planets.”

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