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Tonight I am performing cutting-edge science. I am searching for planets revolving around stars some quadrillions of kilometres from here. My equipment? A laptop and an Internet connection. The cost? Just a bit of my time. The possible benefit? Contributing to discovery of entirely new worlds.

On December 16th, a new project – Planet Hunters – was put online. The aim is simple. You are given a whole series of light curves (graphs) from different stars, and your mission – should you choose to accept it – is to identify anything that might indicate a planet crossing in front of its parent star. It’s easy to learn. In a few minutes you can be searching for far-away planets like an expert.

Planet Hunters uses data from a satellite known as Kepler, whose job it is to study hundreds of thousands of stars over an extended period, looking for signs of planets crossing in front of their parent stars. Planets are very dim compared to stars, so they are almost impossible to detect visually. However if they happen to cross in front of a star, the light from that star decreases momentarily. This decrease can be picked up by powerful telescopes and it is these occurrences that Kepler is keeping a lookout for.

That’s where we citizen scientists come in. Many of these small drops in brightness are not easily detectable by computers. Humans are good pattern recognisers, so we can often see anomalies that a computer might not recognise. Searching through the light curves for transiting planets is a bit like finding a needle in a haystack. The planet, the star and the Earth need to line up exactly, so only a small percentage of stars are likely to show anything of interest, even if they have planets revolving around them. If enough stars are sampled however, new planets will certainly be discovered. Some scientists reckon that Kepler will quadruple the number of exoplanets known to us. We currently know of 700 planets revolving around stars other than our sun.

What hit me about searching were the many different types of light curves available. Many stars are relatively uniform, but others show complex variations and rapid fluctuations. The picture below gives you an indication of some of the star patterns I came across today.

So far in my searches I have come across a few patterns that may indicate a planetary transit. The software permits you to tag and highlight possible candidates. The same pattern is shown simultaneously to other users, so that comparisons can be made and observation errors reduced. If many people are tagging the same feature, then it is likely that something interesting is going on. Having us “citizen scientists” involved is of huge benefit to the real scientists,who would otherwise need to sort through a deluge of data.

Here are my 4 best candidates from my searches so far. They may turn out to be nothing of importance, but in any case for a few hours searching it’s been a fascinating introduction to the world of planetary discovery.


It’s beautiful

If you go out on a dark moonless night, you will immediately know what I mean. The Milky Way, stretching its jagged course across the heavens, is quite a sight to behold. The constellations, particularly the winter constellations, have an elegance and familiarity to them. The Moon is also an appealing object, with its ever changing phases and frequent conjunctions with other planets in the sky. Through a small telescope, planetary disks, galaxies, nebulae and open clusters come into view, often startling in their majesty.

Of course, the beauty of the universe is not limited to what is immediately visible to our eyes. Deep space objects, seen through the largest of telescopes, are candidates for some of the most beautiful things ever seen by human eyes. Who could not fail to be impressed by the wonderful Hubble photos of the Crab and Eagle nebulas, or the views of the outer planets and moons from space probes such as Voyager and Cassini? To see for yourself, each day NASA publishes it’s Astronomy Picture of the Day. Few images ever fail to impress.

It’s extreme.

Nothing can be taken for granted about space. Most of it is unimaginably cold, interspersed occasionally by blisteringly hot stars with coronal temperatures of millions of degrees. Almost everything is racing around at breakneck speed: barreling through space at velocities of hundreds or thousands of kilometers a second relative to us. That’s enough to cause quite an impact if we were to get in their way. All around us catastrophic convulsions are taking place, with vast explosions and unconscionably high energies. This is a Universe of supernovas, neutron stars, magnetars, pulsars and Gamma Ray Bursts – beams of high energy radiation that would eliminate all life on our planet in an instant were our Earth unfortunate enough to stray too close. Black holes exist that can compress the mass of whole stars into volumes a few kilometers wide, creating gravitational fields that nothing, not even light itself, can escape from.

This is the stuff of childhood fantasies. Superpowers. Forcefields. Instantaneous death. The destruction of worlds. It is no wonder that space features so prominently in the minds of the young.

It ignites our curiosity.

Astronomy confronts us with some of the biggest and most challenging problems about the nature of ourselves and the fabric of reality. As a science, it has lead the way in overturning ancient notions of how nature should behave. At one time we believed ourselves to be at the centre of the Universe, with all objects, including the Sun, revolving around the Earth. Astronomers through the ages slowly revealed a different truth. Our star and our home planet are among countless billions in a very ancient Universe. Everything we do ultimately only affects an infinitesimally small piece of real-estate in the cosmos. This discovery, while deeply humbling, is enlightening. It tells us that we will never know everything. Our quest for knowledge is unlimited. We are ants in a cathedral, and what a cathedral it is.

The study of the stars and planets has pushed out the frontiers of knowledge in every direction. It’s contribution to science and mathematics cannot be underestimated. Without astronomy, the modern world as we know it would not exist. Astronomy continues to confound us and guide us right to this day. Gigantic accelerators are busy smashing sub-atomic particles into smithereens to gain greater insights into the nature of matter because objects in space do not always behave the way our current scientific models expect them to. Astronomy has revolutionised our understanding of nature and it will continue to do so.

It tells us about our past.

When you look into space, at any star you care to mention, you are looking into history. You are not seeing the star as it is now, but as it was when the photons of light left its photosphere many years ago. If you can find the Andromeda Galaxy in the sky, you are getting a picture of how it looked two million years ago, long before humans ever roamed our planet. The largest telescopes can see back billions of years ago, to galaxies in their infancy, still in the process of being formed.

History is about ourselves, how we got here, why things are how they are. Astronomy opens history even further by explaining the origins of our planet, our sun, our galaxy – even providing insights into our Universe and how it all started some 13 odd billion years ago.

Astronomy is fascinating even when applied to our own modest human story. We have had an intense relationship with the stars and planets for thousands of years. It guided the ancient cycles of sowing and harvesting. It provided the raw material for belief systems, rituals and religions. It contributed to our language. It assisted with navigation and discovery. In living memory, we have witnessed men walking on the Moon and robot probes being flung out of the solar system – events likely to be celebrated for millennia to come. Our relationship with the stars has shaped the culture of today.

It’s our future.

Astronomy is important to our future, from the short term to the distant long term. Over the coming decades, private companies will take over much of the heavy lifting formerly associated with government agencies such as NASA and ESA. This will create new jobs and new wealth. Bigger telescopes and better equipment will provide insights into reality that will stretch our technological capabilities. Over the coming centuries perhaps we will explore and colonise deep space for ourselves, using technologies yet undreamt of. In the end, billions of years from now, our sun will expand, frying everything on this planet before diminishing in size itself, its fuel spent, its job done.

Perhaps there is a large asteroid or comet out there in space with our name on it. Perhaps our planet will eventually turn against us, forcing us to find a new home. Perhaps we will find a way to cross the enormous gulfs separating us from other stars in our galaxy. All of these possibilities lead us to the conclusion that the stars will feature prominently in the future of the human race.

Astronomy is available to all, from the small child with his toy rocketship, to the octogenarian peering through her telescope at a crater on the Moon. Few endeavours are so wide in scope, so rich in detail, or so marvelous in implication. I invite you to join in.

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