Guest Blog Astronomy Time at the Zoo By Alice Sheppard

   Alice Sheppard moderates the Galaxy Zoo Forum, and we are delighted that she agreed to write our third Guest Blog. Alice prides herself as an amateur astronomer with a lifelong interest. Alice wants to become a professional science writer and promote citizen science. Pulse Project is currently producing a documentary about Galaxy Zoo. In this blog Alice gives us some insight into the wonderful world of Galaxy Zoo.

“Good morning zoo. Espresso machine is turned on.”
    “Ooooh, thanks Half.”
    “I’ll have mine with two sugars and lots of cream.”
    Half65 and his espresso machine are hundreds of miles away, but imagination is a wonderful thing. Many of us come to greet each other’s unknown faces as soon as the boss’s back is turned, or during dim befuddled hours – whatever those may be. “Evening all, I’m almost here . . .”. “Oh dear, which bit is missing?”

    Meanwhile, there’s excitement mounting two clicks away. Someone’s just found a green blob. You don’t find many of those in space, but we’ve found out that they’re a new class of galaxy – small, of low density, but forming stars 40 times faster than our own Milky Way. We call them “peas”. But this pea has a blue blob next to it. Is that a camera glitch?

    Since galaxies are hundreds of millions of light-years away, and asteroids only a few light-seconds, this seems hard to believe – until Geoff Roynon, our asteroid collector, jumps in. “This is an asteroid and hasn't been posted before - should go in the Asteroid Thread. One of the things that mark it as an asteroid is that the "DEBLENDED_AS_MOVING" flag is set on the SDSS page.” But you don’t even have to look at technical flags to know it’s an asteroid. “Asteroids, because they're relatively close to us, seem (because of the Earth's rotation) to move very fast compared to galaxies while the SDSS camera has a look at them,” I explain to my fellow zooite. “Therefore, it shows up in the green, red and blue filters in separate places. In this case the red hasn't shown up at all, but this is pretty usual for faraway asteroids. Nice find and thanks for asking about it - another for Geoff's collection!”

Geoff and I and the person asking about his green and blue blob are not professional astronomers. None of us has an astronomy qualification. We simply stumbled, nearly two years ago now, Galaxy Zoo
    Galaxy Zoo is an online project where ordinary members of the public are invited to classify galaxies from the Sloan Digital Sky Survey (SDSS). No astronomy knowledge is required. Galaxies, like animals, come in specific types – most famously, spiral and elliptical (the famous rotating disks with arms, and golden rugby-ball shapes, respectively). In short, you sign up, and you are given a galaxy and some questions on the screen. As soon as you have done this, another galaxy appears. There were nearly 1 million in our first database. Human eyes do far better than computers, and tests show that amateurs are as reliable as professionals – if not more so. Cosmologist Kate Land remarked when the project was launched: “Astronomers aren't the best people to do this . . . I've found that members of public are much better; they just go with it, on first instinct.”

It was supposed to begin as two small side-projects for astronomers. Kate Land and her colleague Anze Slosar were trying to find out whether spiral galaxies – from our point of view – rotate more in one direction than another. And Kevin Schawinski, now at Yale, was investigating star formation just where it shouldn’t be happening: in elliptical galaxies, which have supposedly run out of “fuel” to do so. What they weren’t expecting was for 200,000 members of the public to sign up and the project to take over their lives.

“Our users are clamouring for stuff to do,” said Chris Lintott, one of the leaders of the Galaxy Zoo project and co-presenter of The Sky at Night. While the “Zookeepers”, as we dubbed them, frantically write scientific papers, the Zoo community build their own collections of interesting or unusual objects, and go far further than merely classifying them. Asteroids weren’t initially part of the plan, but now Geoff has a database of nearly 1000, checking their position when imaged by SDSS, their names if known – and which are new discoveries.

Galaxy Zoo’s most famous find is Hanny’s Voorwerp, a mysterious and so-far-unique object near a spiral galaxy. It is a strange-shaped cloud of very hot gas, but contains no stars or any obvious energy source. The current hypothesis is that the spiral galaxy used to contain a quasar, which has left a “light-echo” in the cloud. It was spotted the way thousands of other objects are: Hanny van Arkel, a volunteer, was given it to classify, joined our discussion forum and asked what it was. This is how hundreds of other people have contributed to science and found out more about what they are seeing.

We have plenty more to find! One of our forum members, Richard Proctor (known as “Waveney”), writes specialised classification webpages for particular types of galaxy we want to investigate, by extracting all the objects from one thread in the forum, or one person’s findings after a search. We’ve done this for the mysterious green “peas”, which are now being studied by Carie Cardamone, a PhD student at Yale – and now we’re doing another one, on irregular galaxies, all by ourselves. Irregular galaxies are small, usually starforming, and neither spiral nor elliptical – and not much studied. “I'm very curious to see how this develops,” Kevin Schawinski remarked on the forum. “To my knowledge, this is the first ‘user generated’ science project ever.”
    The forum is the hub of zoo activity: where image after image is debated, virtual coffee is offered round, astronomy and science are cheerfully explained, and new projects are thought up. It’s also my personal pride and joy, having moderated it since Day 1. “Knowledge is made for sharing, not for overshadowing,” one forum user wrote. And another, “I certainly am enjoying myself! This must be the friendliest forum I’ve ever been on!” I hope you’ll come and join us – just be prepared to be bombarded with posts saying “Welcome to the zoo!” All ages, all nationalities and all levels of knowledge are welcome. It’s certainly the place where I have learnt the most, without having taken any formal classes at all.

Alice is the forum moderator for Galaxy Zoo. You can visit her blog for more interesting stories about the progress of the Zooites and Zoo Keepers.



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