Another paper for the Milky Way Project. The Yellowballs began on the very first day of the Milky Way Project when a user asked me ‘what is this?’ and I wasn’t sure so jokingly called it a ‘#yellowball’, since that’s what is looked like. We use hashtags on, and that user, and a few others, went off and tagged hundreds of the things over the next few months. Before we knew it there was a catalogue of them. However, we still didn’t know what they really were, and so Grace Wolf-Chase, Charles Kerton, and other MWP collaborators have put a lot of effort into figuring it out. The result is this new paper.

Originally posted on The Milky Way Project Blog:


There is a new Milky Way Project paper in the news today, concerning the #yellowballs that were found by Milky Way Project volunteers.

The Yellowballs appeared on the very first day of the Milky Way Project when user kirbyfood asked ‘what is this?’ and I wasn’t sure so jokingly called it a ‘#yellowball’, since that’s what is looked like. We use hashtags on, and that user, and many others, went off and tagged hundreds of the things over the next few months. Before we knew it there was a catalogue of nearly 1,000 of them. However, we still didn’t know what they really were, and so Grace Wolf-Chase, Charles Kerton, and other MWP collaborators have put a lot of effort into figuring it out. From the JPL press release:

So far, the volunteers have identified more than 900 of these compact yellow features. The next step for the researchers…

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Line 1. Let’s start with ‘typical’ humans. The average human adult male is 1.75 metres tall – that’s 3.83 cubits or 5.74 feet. The average female is 1.62 metres – that’s 5.4 light-nanoseconds or 0.008 furlongs.

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You live on Earth (Sol d, perhaps?). This is an Earth-like planet in a Sun-like star system. The third planet of eight in a rich system, including a least one planet populated entirely by robots (Mars, perhaps?). Earth is 12,742 km in diameter and thus has a circumference of 40,000 km or roughly 25,000 miles. Humans live in a thin layer (~20km) around the surface called the troposphere. If the Earth was a beach ball then all life on Earth exists within just 1mm around the surface.

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Through many years of international effort we have managed to keep a ‘space’ station in orbit – just above this troposphere – 1cm above the beach ball. But not high enough up that it can totally avoid the atmosphere – the ISS has to constantly boost itself back up because of air drag. We have sent just 24 people out into deep space, beyond the Earth’s atmosphere. All of then visited the Moon and the last ones returned in 1972: 42 years ago. They were all men, all white, and all American. We could do it again, we could do it better - but we chose not do so. (Mostly for political reasons IMHO.)

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Those astronauts visited the nearest body in space: the Moon – the second brightest thing in the sky . They were kind enough to return some photos to show us how teeny tiny we are, and how delicate out world really is. The Moon sits about a quarter of a million miles away (384,000 km). You could fit all the Solar System’s other planets in that gap.

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But that doesn’t include the Sun – the brightest thing in the sky. The Sun is truly huge. You can fit the Earth inside the Sun a million times. It has more than enough room for all the planets and then some. The Sun itself sits 93 million miles away – which means that light takes 8 minutes to reach us from the Sun. The Sun could have gone out 7.9 minutes ago and you’d only find out… now. Nope: we’re ok. For now.

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And yet we have flung robots into space and downloaded the images they have recorded. Sometimes we take extremely long-range selfies of a sort. Images of the Earth, of humanity reduced to a pixel or two. Here’s one from Mars, one from Saturn and one from out near the edge of the Solar System – taken by Voyager. These images collectively earn us the moniker ‘pale blue dot’. Out by Pluto, the Sun itself is has dimmed to look like an other stars. From Saturn, we are just a couple of pixels as seen by the Cassini probe:

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And truthfully, the Sun isn’t so special. In fact there are stars which make the Sun look even smaller than the Earth does here. VY Canis Major is staggeringly big – and could encompass the Sun 1,000,000,000 times. That’s a million trillion Earths. Oh and VY Canis Major isn’t even visible to the naked eye because it’s so far away that we can’t detect its photons without aid of telescopes or binoculars.

Which brings us to the Galaxy. The Sun is just one of hundred of billions of stars orbiting around the Milky Way. If the Sun was a blood cell then the Milky Way is the size of Europe. The Milky Way is staggeringly big also staggering diffuse – so much so that if you took two Milky Ways, and hit one with the other, then in all likelihood no two stars would collide. They would pass though each other like smoke.

In fact this will happen. The Andromeda galaxy – which is a lot like the Milky Way – is on a collision course with us. In about 4 billion years it will begin to merge with our galaxy in a spectacular collision. We see these happening elsewhere but the sheer scale of this vision in our own night sky makes me want to get a time machine and jump forward to see it happen. The Earth is unlikely to be affected by this, because of the lack of collisions – however our night sky will be spectacularly altered for hundred of billions of years. Makes you realise how dull it is right now. Just kidding!


But the Milky Way and Andromeda are just two out of hundred of billions of galaxies in the Universe. Gigantic stellar continents floating in a vast, void of almost nothing. Galaxies themselves form structures, and as we have looked deep into the cosmos we have seen one such structure: the Sloan Great Wall. A thick chain of galaxies, loosely bound to each other by gravity, stretching 1.4 billion light years across the Universe and about 1 billion light years from the Milky Way. It’s 1/60 of the Universe across. And yet there are even bigger thing out there.

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The largest known structure in the Universe is the Hercules–Corona Borealis Great Wall. At 10 billion light years across, this huge filament of galaxies in 1/10 the size of the observable Universe. It’s 100,000 time the size of the Milky Way, and 70 million trillion times bigger than than the Sun. We don’t have a good picture of it, but we know it’s there. It’s 7,000,000,000,000,000,000,000 times bigger than the Earth, which is very much bigger than you. I refer you to line 1.

Help Count the Stars

January 1, 2015 — 1 Comment


Here’s a fun thing to do this January: help count the stars to see how dark the sky is near you. While you’re looking for Comet Lovejoy, take a moment to count some stars for a school project.

Over the past few weeks I’ve been helping A-Level student, and fellow Witney resident, Jesse Lawrence with a BSA Crest Award project. He opted to go for something with a local twist and has decided to map the quality of the dark skies around Witney. Now he’s embarked on the last phase of his project: crowdsourcing a dark sky map by recruiting volunteers (that’s you!).

It would be fantastic if you could add your own observations to the project. All you have to do is count the stars an fill in this form. For now, you need to be located in the Northern Hemisphere.

Although this began as a local project, the system is up and running and will work at scale so please fill in the form from anywhere – not just Witney.

You have to go out on a clear night and then report your location (your postcode or lat/long) along with the faintest star you can see in the Plough (or saucepan, or big dipper, in Ursa Major). You just need to use Jesse’s map on the online form at Find the faintest star that you can see from those marked with letters on the form. That helps identify the limit of brightness for your location. Repeats over several nights will help average a better result, as will multiple people observing from the same spot over time.

Screenshot 2015-01-02 21.23.12

The results appear on a live-updated map, which you can see at The more people that join in, the better the final map will be.


Hubot is an open source chatbot created by GitHub. It’s used by various companies, groups, and other techie types, to control systems, gather information, and put moustaches on things – all via chat interfaces. Hubot can be adapted to work via IM, GTalk, Twitter, IRC, and other platforms. ‘Chat Ops‘ is a growing trends, and because it is simple, and quite charming, I think it may stick around.

I’ve just finished an epic few days at the sixth .Astronomy event. This is my own conference series, and I’m gleefully exhausted from several days of talking, making, and hosting my favourite event of the year. More on that in a later post. During the .Astronomy 6 Hack Day (sponsored by GitHub in fact!) I worked on making an astronomical Hubot – which I’ve called ‘botastro‘ in honor of the #dotastro hashtag from .Astronomy itself.

@botastro exists only on Twitter (for now) and to interact you just tweet it. For example if you tweet

then @botastro will reply

You can can send multiple messages to the bot, but I have a growing list of other ideas too. Currently you can say things like:

  • @botastro sunrise Chicago
  • @botastro apod me
  • @botastro galaxify hello world
  • @botastro fun fact
  • @botastro moonphase
  • @botastro tell me about Jupiter
  • @botastro show me Perseus
  • @botastro gif dog
  • @botastro exoplanet me

Asking botastro to ‘galaxify’ something results in text made up of galaxies from Galaxy Zoo (thanks Stuart Lynn!) which is pretty


and asking it to ‘exoplanet me’ gives you an exoplanet from the catalogue (thanks to Dan Foreman-Mackey and Geert Berensten). The results you get when asking it to show you something or tell you about something are sourced from Stuart Lowe‘s lookUP service, and the space gifs come from Giphy.

These may be silly and fun, but more complex actions become possible – especially once I get a bit more used to Coffeescipt, the language this bot is written in.

@botastro is open source (on GitHub, naturally) and I’d love it if people wanted to add functionality. If you want to try, you’ll need to fork the repo, create a new script, and submit a pull request. Hubot is outlined here, and you can look at botastro’s other scripts for examples too.

This was an amazing week.

On Wednesday the Rosetta spacecraft launched the tiny Philae lander on a 10km journey to the surface of a comet: a mountain-sized rock, millions of miles from Earth. This was a first that touched many around the world, millions of whom who followed the event online. It took ten years to get Rosetta into a position where this was possible, with teams of people working to make it happen in Europe and around the world.

On Friday my nephew Taliesin, who has Cerebral Palsy, walked 1km to school for the first time in his life. He did it for Children in Need – you can still donate! No wheelchair, just his walking sticks. This was also a first that touched many around the world, hundreds of whom followed the event online. It has been three years since Tal had an operation (SDR) to improve his condition, one that ultimately made this walk possible, with a team of fundraisers at home and a medical team in St. Louis; not to mention his tireless parents.

Tal and Philae both had their mountains to conquer but, for me at least, one of these story’s is more incredible than the other. So here’s my favourite image from the past few days – and it’s entirely Earthbound.


Sadly, Philae has powered down, and its mission may have come to an end. For Tal though, things continue to improve. Tal is an inspiration to so many, and I’m incredibly proud of him and his family for going the distance this week, and for the past few years.

Hopefully I’ll report on both these stories in the future. Meanwhile you can read Tal’s story on the BBC. You can support kids like Tal, and their families, by checking out SDR Wales, or supporting organisations like Bobath Wales.

H₂O might be the most familiar chemical compound on the planet. Many people know that water is H₂O, but most wouldn’t think about what that means in a chemical sense. Water is a remarkable molecule made of two Hydrogen atoms bound to a single Oxygen atom: H, H, and O. Water’s special properties give us life as we know it, and we’re mostly made of it too. It’s less dense as a solid (ice) than as a liquid, which has major consequences for the planet and its climate. Water is also really good at storing heat, and it stays liquid over a wide range of temperatures, also very handy for life as we know it.

In short: water is amazing: but can we destroy it? Yes. With just two regular pencils and a 9V battery, you can actually break water down into it’s Hydrogen and Oxygen components, and watch them boil away as bubbles of gas. This is fundamental chemistry available to anyone at home, with stuff you might have lying around.

You’ll need some salt, a 9V battery, a drinking glass (or other transparent container), two pencils, and some wire. It ’s best to get some cheap cables with crocodile clips (I bought these ones from Amazon), since they make it much easier.

Pencil Electrolysis Kit

Pour some warm water in the glass and stir in a tablespoon of the salt. You should probably also open a window – or at least don’t do this in a tiny cupboard – a small amount of Chlorine may be produced as you do this experiment; it’s not dangerous as far as I can tell, but best to be safe.

Sharpen both the pencils at both their ends – so that’s four pencil points  in all. Connect both nodes of the battery to a different pencil using the crocodile clips.


At this point I suggest you distract yourself by trying to touch the free pencil tips together to make small sparks! The electrons really ‘want’ to make a circuit and can jump across a short air gap, ionising the air and making a crackle and an electrical arc. It’s a 5mm lightning bolt on a pencil tip. But anyway, back to main point of this…

Put the free pencils ends into the water, and don’t let the tips touch. Now for the science! At this point the water becomes part of the circuit. Electrons flow down one pencil, across the water and back into the other pencil. This creates a circuit and electrons flow around it. You’ll know it’s working because this process quickly creates bubbles at the pencil tips in the water. It happens almost instantly.


The energy of the electrons in the circuit is enough to break the water into Hydrogen and Oxygen ions: electrically charged versions of the elements themselves. These ions then flow to the oppositely-charged pencil tip, creating an electric current. This is known as electrolysis.

At the negative pencil tip (the anode) positively charged hydrogen ions (or just protons to some people) meet and form hydrogen gas (H₂) that bubbles to the surface. The positive pencil tip (the cathode) draws the negative Oxygen ions and form O₂. It’s a bit more complex than that, if you’ve bene counting electrons, but that’s the overall result. This is electrolysis of water and it’s the world’s primary way of producing Hydrogen – for example for hydrogen fuel cells.

You might be wondering why we need salt. This could be done without salt, but it wold happen more slowly. Can should try it, to prove it to yourself. Salt dissolves into the water creating ions of its own. These flow around the circuit too (creating Sodium and a tiny volume of Chlorine gas) and helps increase the circuit’s overall flow of electrons. You might be able to smell the faint whiff of Chlorine if you do this for long enough.

If you want to take this further, you might think about how to collect the Hydrogen and Oxygen separately – and what you might do with them if you were doing this on an industry scale.

Since 2008 I have been running .Astronomy, which is a meeting/hackathon/unconference that aims to be better than normal meetings and to foster new ideas and collaborations. It’s a playground for astro geeks that is more specific than a general hack day, but way more freeform that a normal astronomy meeting. At .Astronomy we have developed into an amazing community.

I know people that have gotten jobs because of .Astronomy, changed careers because of .Astronomy – or even left astronomy because of .Astronomy (in a good way!). We have evolved into an interesting group, with a culture and way of thinking that we take back to our ‘real’ jobs after each event.

In short: it works. Now I’d like to work out how to spread the idea into more academic fields. We’re looking for people in other research areas, such as economics, maths, chemistry, medicine and more.

Adler Planetarium

I have funding from the Alfred P. Sloan Foundation to bring a handful of non-astronomers to this year’s .Astronomy, in Chicago at the amazing Adler Planetarium (December 8-10). The aim is to meet up at the end, and discuss whether you think it could work in your own field, and what you’d need to make that happen. If you’re a researcher, who isn’t an astronomer, and you think this sounds great then that could be you! We have funding to pay for flights, hotels and expenses. It will be a lot of fun – and despite the astronomy focus of the event, I think most researchers, with a bit of tech experience, would get a lot out of it.

If you’re interested then fill out the short form at or email me on for more information. We are following a formal selection process, but we’re doing it very quickly and will decide by Nov 7th, to allow enough time ahead of the event to make travel plans and such. So don’t delay – do it now!

If you don’t think you’re the right person for this, then maybe you know who could be. If so, let them know and send them to for more information.

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I’ve been called a lot of things but ‘rebel’ hasn’t come up too often. Not that I mind. As part of a Mazda campaign, I’m being highlighted as one of four TED Fellows* who are ‘Mazda Rebels’. The other three are thoroughly impressive and I recommend you take a look. There’s an online vote where the pubic help chose whoever they think the deserves a Mazda grant to help their project.

My video can be found here. It’s lovely and I really enjoyed making it. It nicely describes my work with Zooniverse (special guest starring Brooke Simmons as a Snapshot Serengeti volunteer!) in a fun, accessible way. We had a laugh creating it, and they have kept many of the out-takes in the video, which I rather enjoyed.

If I win the vote then I’ll be using the money to kick-start the Zooniverse’s efforts in disaster relief with a ‘First Responders’ project. Think Milky Way Project but with aerial photos of recent disasters, with volunteers helping locate resources, danger, and people. This is something several of us at Zooniverse HQ are very keen on, and using the power of crowdsourcing in realtime after a disaster makes a lot of sense.

I highly recommend that you take a look at all four videos and vote for your favourite here:

* Applications are still open to become a 2015 TED Fellow – I can highly recommend it!


Really pleased to make my Milkman app available for all MWP users :)

Originally posted on The Milky Way Project Blog:

I’ve been building a new app for the Milky Way Project called Milkman. It goes alongside Talk and allows you to see where everyone’s clicks go, and what the results of crowdsourcing look like. It’s open source, and a good step toward open science. I’d love feedback from citizen scientists and science users alike.


Milkman is so called because it delivers data for the Milky Way Project, and maybe eventually some other Zooniverse projects too. You can access Milkman directly at (where you can input a Zooniverse subject ID or search using galactic coordinates), or more usefully, you can get to Milkman via Talk – using the new ‘Explore’ button that now appears for logged-in users.

Clicking ‘Explore’ will show you the core view of Milkman: a display of all the clicks from all the volunteers who have seen that image and the current, combined results.

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Milkman 2

Milkman is a live, near-realtime view of…

View original 180 more words


‘Something awesome from the Zooniverse every day’ was the tagline that we came up with, almost a year ago, for a new Zooniverse blog: Daily Zooniverse. Grant Miller had recently arrived to work at Zooniverse HQ in Oxford and I had a todo list of things I’d always wanted to try but hadn’t found the time for. The Daily Zooniverse was right at the top.

The Zooniverse has spawned more than 30 citizen science projects, generated almost 100 peer-reviewed academic publications, and engaged more than one million people! Surely we had the capacity to share one cool thing every day? That was the challenge I laid at Grant’s feet last year and he has risen to it. Somehow, for the past 359 days, Grant has managed to post something (anything!) Zooniverse-related to the blog at

Team birthdays, project status updates, suggested projects, and galaxy of the week are some examples of the blog’s regular features. There are the new projects that launch, the cool things the community find on Talk, and the awesome finds that just appear from seemingly nowhere. I love following this blog because it adds little bit of Zooniverse into my RSS feed each day. I often see things I didn’t know about myself!

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Congratulations to Grant on the blog’s birthday this week! Find the blog at or follow it via RSS, Twitter, Facebook, G+, and Tumblr.