Exoplanets: my two cents

Like everyone else, I was very excited when I heard about NASA’s big announcement last month. What could it be? A new space craft? Pluto’s long-awaited return to planet status? Aliens? Yeah, it’s definitely aliens. But what it actually was, blew my mind. Yeah, I mean we’ve all heard of exoplanets before right? But this was something different. I mean seven Earth-sized planets with three of them in the habitable zone that could quite easily harbour water AND MAYBE EVEN LIFE. It sounded too good to be true but nope there it was, on TV, online, in magazines and on the radio. The Trappist-1 system is one of the most intriguing discoveries in years but what does it really mean? Read on…

So, what actually are these planets then?

The Trappist system is 40 light years from Earth, which in the grand scheme of things, isn’t all that far. The exoplanets and their star Trappist-1 lie in the constellation Aquarius and, for the moment at least, have been named B,C,D,E,F and G. Easy to remember then! The seven planets are all of a similar size and naturally get colder the further away they are from the star. The planets are so close to each other that if you stood on the surface of one, you could see the clouds, rivers and mountains of the neighbouring planet. The discovery is a record for the greatest number of habitable-zone planets ever sighted and the first known system to have so many Earth-size planets around its star. This is why it’s so very important.

How did we stumble across them?

We have NASA’s Spitzer Space Telescope to thank for this. An infrared telescope, it found the faint glow of Trappist-1. This happened in 2016 and NASA spent many months analysing what exactly was in the system before publishing their findings last month. The Hubble Space Telescope was then assigned to the task of finding out a little more about these intriguing exoplanets.

How do they differ from our solar system?

For all the excitement on the discovery of Earth-like planets, they actually differ quite a bit. First and foremost, Trappist-1 is a dwarf star making it quite a lot dimmer than our Sun. Experts predict that life would be significantly darker (yet still very much habitable) on all these planets as we can see from this render:

The planets themselves are also much closer to their star than we are. In fact, all seven planets are nearer than Mercury is to our Sun. As you would expect, Trappist-1 looks gigantic in the sky of these exoplanets compared to what we see of the Sun on Earth. Despite every celestial body being so close to the star, it’s believed that the furthest planet from Trappist-1 is an ice world. Just goes to show how dim this star really is.

Perhaps most interesting is the likely fact that each of the planets are tidally locked to Trappist-1. This means that one side of the planet will always face the star while the other side will always be shrouded in darkness. This would make everything from the seasons to the weather completely different to anything we have here on Earth. It’s also believed that the planets have hydrogen based atmospheres.

Can we get there?

Even though they’re close compared to other exoplanets, the Trappist planets are still very much out of our reach. At 378 trillion kilometres from Earth, no rocket we have will even get close. But this is now and in the future with the use of super materials like graphene and exciting developments in metallic hydrogen, they could be reachable. But, let’s just stick to missions to the Moon and Mars for now!

Aliens, are there aliens?

Maybe. But no sign as of yet. But maybe.

Will we find more in the future?

Almost definitely! The universe is so expansive and the power of our telescopes is improving all the time so new exoplanets will be found frequently. Maybe even more habitable than the Trappist system, who knows?

All images credit NASA.

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