365daysDate: May 21, 2009

Title: Hanny’s Voorwerp and the Galaxy Zoo


Podcaster: Ted Judah

Organization: Sonoma County Astronomical Society

Description: In 2007 Dutch school teacher Hanny van Arkel discovered a unique deep space object never before described… from the comfort of her computer chair! Learn about how her love of music led her down a path of astronomical discovery.

Bio: Ted Judah is a total amateur. Amateur astronomer, carpenter, surfer, artist, designer, photographer, musician, cyclist, husband and papa.

Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by [brief dramatic pause] Anonymous on behalf of The Onion Router Project. The Onion Router Project provides free, open source software securing privacy on the Internet for all of Earth’s inhabitants. Find out more at


Hi this is Ted Judah for 365 days of astronomy.

I’m here today to tell you an interesting story. It’s about astronomy, but it also about citizen science in the age the internet. It’s a human interest story of a school teacher from the Netherlands, while using the website Galaxy Zoo, discovered what was to become known as Hanny’s Voowerp (ahem, I’ll try my best Dutch here): Hanny’s Voorwerp.

Hanny: Oh that’s very well. I love the English or American accent to that very Dutch word. It’s brilliant. (Laughs)

This is Hanny van Arkel. Hanny is a bright, and lovely woman who I am interviewing via the internet from her home in Herleen in the very south east of the Netherlands.

Hanny, what do you do for work and for fun?

Hanny: I teach. Mostly at primary schools. And at the moment, mostly, as a replacement teacher as they say – which is how you start out here really. I only graduated in 2007. So I teach every subject I mostly teach music at the moment.

I have a passion for music. And besides listening to it, I play guitar myself. And I’m an amateur astronomer nowadays.

That is what I hear. Interestingly it was your love for music that led her to Galaxy Zoo and ultimately to your astronomical discovery. What is Galaxy Zoo and how did you found out about it…

Hanny: Uh, Yeah. I found out about this. It’s an online astronomy project where real astronomers ask the public to help them classify galaxies. You don’t need to know anything about galaxies or astronomy cause there is this short explanation online and you get to see these beautiful pictures and you classify them by clicking on a button to tell them what shape you think it has. Um, as it turns out computer programs aren’t as good as this as the human brain so that’s why they asked the public. And, I heard about it through Queen’s guitarist Brian May actually. (Galileo, Galileo, Galileo Figaro!) I admire him for his music, but also he writes for his website ( and well he mentioned this and I thought, “Oh, sounds good let’s check it out.”

And check it out she did.

Now… Galaxy Zoo uses images that were taken automatically by the Sloan Digital Sky Survey using a camera mounted on a telescope at the Apache Point Observatory in New Mexico. Galaxy Zoo uses this comprehensive sky survey to provide valuable information about how galaxies evolve. Now most of these galaxies have been photographed by this robotic telescope, and then processed by computer – and number, I believe, in the millions. So, chances are, many of the objects presented to the users of Galaxy Zoo have never been seen by human eyes before.

A week into classifying objects Hanny came across a strange and unusual object that caught her eye… What was that Hanny?

Hanny: Well that was this Hanny’s Voorwerp… well at that moment I didn’t know that it was something unusual. Um, it looked… it looked like an irregular galaxy because… well actually it had the same characteristics, it has remarkable form, and it’s deep blue but it didn’t quite look the same as one of those. Though that wasn’t an expert opinion – I was only around for a week, and you know I was curious and I just thought well let’s send them an email and ask.

So you wrote and asked about this object?

Hanny: Yeah I said, “What’s the blue stuff below? Anyone? Does anyone know? But nobody did really. And not even, you know, the astronomers were really busy because, well, it turned out to be such a success – the whole project and they had lots of e-mails and mine just was one of them. So the first response was, “Yeah it looks interesting, but they didn’t really know what it was until they indeed started looking at it with different telescopes and it turns out that the human eye would actually see it as green.

Well people say it looks like a frog. It looks like Kermit who’s doing a dance. Which is… A green kind of cloud really, well you can see a lot of things in clouds.

Kermit Sings: Why are there so many songs about rainbows…?

How did it get the name Voorwerp?

Hanny: Well, Voorwerp is just the Dutch for “object” so basically all the stuff around me on my desk are “voorwerpen” and in the beginning, Chris Lintott from Galaxy Zoo – he thought it was an exotic description of the object I found in the sky but… so well yeah Hanny’s Voorwerp is the name of this object I found and um that is a new class of object I’ve been told. It’s a gas cloud and it’s about 6 or 7 hundred million light years away from the earth – really far away. It’s very light and hot but it hardly hasn’t got any stars in it. And they call it a light echo because, they think, it reflects the energy from this galaxy next to it.

Why do you think major news media such as the BBC, CNN (and now the 365 Days of Astronomy) are interested in this object?

Hanny: I think because it’s one-of-a-kind. I don’t think there is another one at the moment that we know of and I’ve been told that if it is what they think it is (and they’re still investigating it) but it can teach us a lot about galaxies in itself. And um, well it’s a great story I think that it’s a great human-interest story as well because there was lots of press attention for it. You know, because, how can a Dutch schoolteacher, like me, who hasn’t done an astronomical course or anything – and then, you know, you just discover something which also gets your name. That’s… that’s a cool story – I guess.

It really is and it kind of speaks to the power of the internet and internet astronomy…

Hanny: Yeah absolutely, citizen science rocks. (Laughs)

So what can people do to draw attention to anything interesting they may find on galaxy zoo?

Hanny: Well there is Galaxy Zoo 2 now. There is a 2nd part of the project. And there is a button where you can more easily say there is something strange on this picture, but besides that there is indeed still the forum where you can also ask what other users think about it.

Now as I record this, the Hubble Space telescope has not yet been repaired but by the time you are listening to this podcast in late May – hopefully everything went perfectly and everything works perfectly. I mention this because I read that Hanny’s Voorwerp was approved to be imaged by the Hubble. Is this true?

Hanny: Yes, that’s correct. We wrote a proposal and that was accepted so if all goes well we should be hearing about that soon. So, that’s the Hubble and there was also this Japanese telescope which does x-ray and they actually just observed it – Well, IC 2497 which is the galaxy next to Hanny’s Voorwerp but the are still working on the data and these things just take time. Um and we also have time with the XMN Newton telescope which also does x-ray but at different wavelengths. Um so yes those things are still planned.

It was fun to find out, we found out actually last year – the 30th of May which is my birthday and as a coincidence they wrote this email saying, “Yeah, your proposal is approved, so yeah that was a good birthday present then. (Laughs)

Finally, Hanny, what was your interest in astronomy before all this Voorwerp stuff?

Hanny: My interest… I mean who doesn’t like to look at a dark sky? But I don’t have a telescope and I didn’t do anything with interest really before Galaxy Zoo. And yeah, well now I do – not that I have a telescope now, but… but yeah I’ve learned a lot about astronomy and yeah … I like it.

Thank you Hanny

Now I suspect that if your listening to this podcast that you like astronomy too. If you would like to learn more about Hanny and Hanny’s Voorwerp please visit her website: I also want to give thanks to the Zoe Keating – she is the talented cellist who gave me permission to use her music.
I’ll have links in the show notes.

A quick update as promised for those who care: my observatory is still a work in progress.

Thanks for listening.

Hanny: Bye!

End of podcast:

365 Days of Astronomy
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