The notion of planets orbiting stars other than the sun is not new but advances in technology is bringing us ever closer to finding alien life, explains Mark Evans
The hunt for ET really is hotting up. Just a few decades ago, the idea of alien life was primarily the realm of fiction. In reality, it seemed the universe was a cold, dead place bereft of life, save for what clings to the surface of planet Earth.
Then came the exoplanets. Super sensitive telescopes began recording slight dips in the starlight reaching us across the void, revealing orbiting planets many light years from our own solar system. Cosmologists were amazed by the discoveries, but not too surprised. After all, the notion of planets orbiting stars other than the sun was speculated upon by the Italian philosopher Giordano Bruno in the sixteenth century.
Early discoveries of exoplanets in the mid-1990s were of gas giants many times larger than Jupiter. Slowly, as the technology evolved, we began spotting smaller, rocky planets until they found Kepler-452b in July 2015 some 1,400 light years away. What made this rocky world different was that it orbited in its star’s so-called ‘Goldilocks’ zone, not too hot and not too cold, but just the right distance to allow water to remain in liquid form on its surface. Excited scientists labelled Kepler-452b ‘Earth’s Cousin’ and ‘Earth 2.0’.
If ET really is out there, chances are it will be living on one of these second Earths. Currently, there are 3,501 of these known planets, all with the potential of harbouring anything from microorganisms to civilisations. On August 24 last, mankind’s enduring quest to find out if we are alone in the universe took a giant leap. Our cosmic next-door neighbour — a mere 40 trillion kilometres away — possessed such a planet: Proxima b. Suddenly, the hunt for aliens was almost physically within reach. Last April, the Starshot project, funded by Russian billionaire Yuri Milner and backed by Prof Stephen Hawking, announced plans to send 1,000 nano-ships to the Alpha Centauri system in just 20 years by accelerating the tiny crafts to 15%-20% of light speed using lasers.
While we wait for technologies to improve, another project that’s been decades in the making is counting down to its 2018 launch date. This is the successor to Hubble, our eye on the universe, and it is called the James Webb Space Telescope (JWST). It’ll feature a mirror three times larger than Hubble’s, as well as a device that was built by Irish scientists. The Mid-Infrared Instrument, or MIRI, was designed and tested by experts at the Dublin Institute for Advanced Studies (DIAS).
Prof Tom Ray, professor of cosmic physics at DIAS, says the James Webb telescope is so powerful that the light from Proxima b’s parent star will drown out any attempts at getting a closer look at the rocky planet. However, the Irish-made instruments will give the hunt for alien life a massive boost.
“MIRI has a device that will enable JW to see planets around stars,” says Prof Ray. “However, Proxima b is too close to its star. We’ll be looking at far more distant systems and will be able to see more planets — which will be just a pixel in size — but we’ll be able to break down the information to tell us something about the planet’s atmosphere. We will be able to tell if there is a lot of carbon dioxide which could signal some kind of life.”
Everything about the James Webb space telescope is big. A big device for big science. It comes with a $9 billion price tag (Hubble cost $2.5bn) and will orbit beyond the moon.
“I like to tell people that if you could get in your car and drive directly upwards, you would reach Hubble in about four or five hours. However, JW will be placed in an orbit around the Earth that is beyond the moon. The reason for this is to get away from the heat of the Earth. If our instruments are trying to detect infrared waves then they must avoid local heat. Our instruments must operate at no more than seven degrees above absolute zero — that’s about -267 centigrade. If you look at a picture of the JW you’ll see the sun shields, they’re so powerful that it’s the equivalent of putting on factor 10 million sunscreen.”
Prof Ray is excited by JWST and you would too if you had the chance to play with a $9bn toy that’ll be located a million miles away. As part of the deal his team will get ‘guaranteed time’ to work with the telescope. They intend to point it at baby stars to learn how solar sytems, including our own, came to be.
“We know that newborn stars are extremely luminous. When I say new stars I mean stars that are ‘only’ about 100,000 years old. You have to remember that the sun is about 5,000 million years old. So when we look at the formation of these young stars we’ll see the creation of basic elements. It’s amazing to look at because they emit enormous jets of matter many light years in length, a bit like a Star Wars lightsaber, something we call a collimated jet. By looking at these jets we get to look back in time and witness what it was like in the early history of our own solar system.” While the Dublin team prepare to zoom in on gigantic jets of light, other teams around the globe will use JWST to try to sniff out ET in the darkest corners of the universe. If the truth really is out there, then an Irish-made device could be on the brink of finding it.
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