Science

Unlocking the secrets of our universe

Far infra-red astronomy PhD student Chris Clark reports from this year’s National Astronomy Meeting and discusses the latest advances in the field and how Cardiff researchers are at the forefront of these findings

Astronomy is very much in the public imagination at the moment. Courtesy of the “Cox Effect,” Joe Bloggs is more likely than ever before to know the difference between black holes & supernovae.

Applications to physics and astronomy courses at universities have spiked. Millions of members of the public have taken part in “citizen science” projects, such as Galaxy Zoo & Planet Hunters, classifying distant galaxies and discovering planets. And just the other week, a lady camping in mid Wales, phoned up Cardiff University’s astronomers to tell us that she’d been woken up in her tent by an “electromagnetic phenomenon,” and would we like to investigate it?

Since Isaac Newton, Britain has punched above its weight in the sciences (although this may soon change in light of funding cuts), and astronomy is no exception. The Royal Astronomical Society is the world’s oldest national institution for the science and every year it gathers together the UK’s research astronomers to discuss their latest discoveries at the National Astronomy Meeting; this year in Manchester, along with Germany’s equivalent, the Astronomische Gesellschaft.

Physics is in an era of big machines. The Large Hadron Collider (which has received much press for its inability to destroy the world) is a fairly impressive nine kilometres across. But astronomers won’t  be outdone by mere particle physicists, and NAM’s attendees heard about the plans for the Square Kilometre Array (SKA), a collection of over 10,000 radio telescopes, which will work together as one big super-telescope, spread over 3,500 km. When up & running, it’ll gather more data every day than the rest of the planet put together.

The SKA will be sensitive enough to see back to the early days of the universe, revealing to us how the cosmos reacted to the very first starts, and helping us unravel the secrets of dark matter (the mysterious, invisible stuff that makes up 75% of the mass in the cosmos), dark energy (the even more mysterious force causing the universe to expand at an ever-increasing rate), and perhaps even discover biological molecules floating between the stars – things like amino acids that are essential to living things, and which may have fallen from space to provide the building blocks of the first life on Earth, and maybe beyond. Construction is due to start in 2016.

The potential for life elsewhere also came up in a much more practical sense, at a talk by the University of Colorado’s Prof Fran Bagenal about NASA’s Juno mission. Juno is currently en route to Jupiter, to explore the giant planet’s aurorae (its versions of Earth’s Northern & Southern lights), and to probe what the planet is like beneath its thick cloud layers, all the way down to the possible Earth-sized diamond that some suspect may be at Jupiter’s core (that may sound daft, but bear in mind that a planet made mostly of diamond was discovered not long ago).

Jupiter’s fourth-largest moon, Europa, is understood to have a massive ocean under its icy outer layers. This ocean contains twice as much water as Earth’s, and is likely to be chock full of the ingredients needed for life to form & thrive, making Europa our best candidate for extra-terrestrial life. So seriously do NASA take the possibility of life on Europa, that when Juno has finished its mission of exploration, they intend to destroy the probe by slamming it into Jupiter’s super-dense atmosphere, to avoid the risk of it accidently crashing on Europa; were that to happen, bacteria from Earth that stowed away aboard Juno could contaminate any native life they find.

No area of astronomy has caught the public imagination quite like the discovery of exoplanets; planets orbiting other suns. Over 750 have been detected to date, most of which are gas giants. They’re so far away that they’re next to impossible to see directly, so astronomers must use clever tricks to uncover their presence. Spearheading this search, NASA’s Kepler telescope has spent three years orbiting Earth, staring at the same 170,000 stars, watching for the slight “wink” in a star’s brightness when an exoplanet passes in front of it.

NASA’s Natalie Batalha spoke at NAM about how Kepler is getting closer and closer to finding an Earth-sized exoplanet in the “Goldilocks zone” around a star, where it would be just the right temperature for liquid water and, perhaps, life. So far, Kepler has discovered 61 exoplanets for certain, but has found over 2,300 good candidates, each of which stands about a 90% of being real. And Dr Batalha revealed that among those possible exoplanets, there is a candidate that is both the size of Earth, and in its star’s goldilocks zone. If confirmed, it will be some of the biggest news in human history; the first potentially habitable planet found beyond the Earth.

Kepler’s ability to watch the miniscule winks of distant stars highlights an often-unconsidered fact – for the vast majority of history, astronomy has depended upon one thing: light. But many of Cardiff’s astronomers at NAM were there to talk about how they’re working to change that. Our university is at the forefront of an entirely new way of doing astronomy, in the race to be the first to detect gravitational waves. Gravitational waves are ripples in space & time, predicted by Einstein’s general relativity, and caused by cataclysms such as black holes smashing into one another, or massive stars exploding as supernovae. As such, they give us a way to uncover what’s going on at the heart of these extreme events, where we could never hope to look using regular old light.

Gravitational waves will make an object (including people) physically expand & contract in size when they pass through it. But picking them up is a massive challenge, as the change in size they cause is 0.0000000000000001%; the equivalent of the entire Great Wall of China gaining all of ten billionths of a millimetre in length. So to find gravitational waves, scientists bounce lasers back & forth through tunnels kilometres long, looking for those tiny variations in length, using the most sensitive measuring equipment in history.

We’re currently at the cusp of being able to detect them, and it’s work done by gravitational astronomers at Cardiff that will pick out their elusive signals. The only gravitational wave detector online for the next couple of years, GEO, is joint-lead (and currently partly manned) by Cardiff researchers.

Cardiff is also heavily involved with the Herschel Space Observatory, the largest telescope ever sent into orbit. Instrumentation experts here built key components for its cameras, sensitive to light far beyond what our eyes can pick up. Herschel can see the far-infrared “glow” of stardust floating in space, at temperatures below -200°C. This dust blocks the visible part of the spectrum (if you look up at the Milky Way on a clear night, the dark streaks you can see are because of dust hiding the stars behind), but Herschel’s gaze can pierce it, showing us stars being born in their dusty cocoons.

Cardiff astronomers talked on how Herschel’s insights are allowing us to piece together stages of star birth in nearby parts of the Milky Way that were previously hidden from view. They also presented results about observations of Andromeda, the closest big galaxy to our own. We can now see where stars are being born, right now, in its spiral arms, and learn about the stardust churned out by Andromeda’s previous generations of stars; the same dust that will one day go on to form new planets and stars.

This year’s National Astronomical Meeting was the most-attended ever, and next year’s should be every bit as successful, especially as it will feature the first discoveries of Europe’s Plank spacecraft (also partly built at Cardiff), whose mission it is to explore the structure, contents, origins and fate of the entire universe, by measuring tiny ripples in the cosmic microwave background radiation (which you’ll recognise as static on old analogue TVs).

In a time of austerity, people question whether public money should be spent on curiosity-driven research that doesn’t directly improve life here on Earth. I’m an astronomer, so I’m hardly an unbiased commentator on the issue. You may argue that the money used for research could be better spent directly helping people in Britain and abroad. But bear in mind that if the government cut the entire UK science budget, it would only increase the funds available for aid and welfare programs by 1.4%.

And don’t forget, exploration of space and astronomy for their own sakes led to the development of global positioning, thermal imaging, airport security scanners (love them or loathe them), dialysis machines, fusion reactors (our only real hope to solve the energy crisis), mammograms, smoke detectors, solar cells, and CAT, PET & MRI scanners, to name but a few.

I think that as a species, we should be aiming for more than consecutive quarters of positive economic growth, or just improving the quality of our lives.

I don’t think we should limit what parts of the natural world we explore merely to those which may reap here-and-now benefits for us to exploit. It would seem irresponsible of us not to strive to understand the beautiful complexity of the universe we’re a part of. If we don’t, who will?

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