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Tonight (and last night too) have been your best chance to see this year’s Perseid meteor shower. With little or no Moon to wash out the skies, it’s a great chance to see, and to snap a picture of, this fantastic annual display.

Astrophotographer and general space image wizard Mel Gigg has produced a superb animation of a Perseid meteor disintegrating in the night sky above the UK (Near Chipping Norton in fact). In case you’re having trouble seeing the animated GIF here’s the direct URL.

The detail, particularly on the trail the meteor leaves behind, is just amazing. If you aren’t already, follow Mel Gigg on Flickr for more stunning images.

Although the peak of the show has passed, there’s still the opportunity to see shooting stars like this over the next couple of nights. Find a dark spot, with clear skies and wait (take a hot drink or something if you’re like me). Patience will be rewarded as you must let your eyes adjust to the dark. The Perseids emanate from the North East (in the constellation Perseus) but they fly all over the sky on a good night.

Good luck – and thanks to Mel, you now know what to look out for.

For better or worse citizen science has become a fashionable term, but what is it and why do people like it? Citizen Science is a big component in a larger movement of public participation and engagement. There are makers and hackers everywhere and participation in science feels like it is increasing in general. This is great, and means citizen science is of growing importance.


I work at the Zooniverse. We have a community of more than 850,000 people, who have taken part in more than 20 citizen science projects over the years. You can see the current batch at Last year the Zooniverse received more than 50 years of human effort (and that wasn’t our highest year so far) and our sites span a wide a range of scientific subjects. People seem to really like them. They’re well-designed and thought-through. They aim to produce real results and slowly but surely they are doing just that (see

At a recent event on citizen science in education, hosted by the British Science Association, I was invited to speak about what citizen science is. This was actually quite difficult. There are projects out there that call themselves citizen science but which I would instinctively say were not so – and probably vice-versa. For example, I don’t think that downloading a screensaver to process someone else’s data is citizen science. Recently I’ve found myself debating the particulars with people. If I had to try to define it, I’s say that

Citizen science is a contribution by the public to research, actively undertaken and requiring thoughtful action.

The Zooniverse is about breaking down tasks into understandable components that anyone can perform. We rarely abstract the problem and always try to keep context in frame. You can know (if you want to) that you’re classifying galaxies or cancer cells or ancient papyri and you can also know why. Citizen Science projects often involve non-professionals taking part one or more of the following:

  • Crowdsourcing
  • Mass-participation
  • Data collection (only one we don’t do yet)
  • Data analysis and Eyewire are both excellent examples of crowdsourced data-analysis (much like the Zooniverse) and eBird is a great crowdsourced data collection project. The new Randomise Me site allows you to set up a mass-participation data collection project. In all these cases, people know what they’re taking part in. The Blackawton Bees paper is a perfect example of citizen science that wasn’t based on mass-participation or crowdsourcing – but was both data collection and analysis (by kids!). All are fabulous examples of citizen science.

At the very least: citizen science has to involve ‘citizens’ or volunteers. Over the past few years at the Zooniverse we’ve learned a lot about our volunteers, and why they take part and give up their time. We’ve learned that, above all, people want to make a contribution to science. I think it’s easy to understand why people want to make a meaningful donation of their time and I think it’s heartening that this is the case. We have learned that on the web, participation is more unequal than the least equal societies in the real world, with the distribution of effort in our own projects being comparable to projects like Wikipedia or Twitter or countless others. This means that most users do little and some users do staggering amounts but that this is fine online. We have also learned that scale is relevant. Sometimes you need 500 people, sometimes you need 500,000. You should know before you embark on your project.

The aim of citizen science ought to be to undertake research and discovery. That is surely wrapped up in its definition as a subset of science. It is not outreach or education – which our sites are often confused with in academia. The goal of outreach and education are to inform and teach, and in many cases citizen science can be used as a tool to do so. That intersection fascinates me but I’m not an educator and I’m starting to think that it is only educators who are able to successfully bring this stuff into the classroom, lecture theatre or tutorial. But that’s another post altogether [1].

Above all we’ve learned that you don’t just launch projects and cross your fingers; it’s 2013: that time has passed. The web is a sophisticated place and an awesome citizen science site can go far and do a lot of good work. Sadly it is also possible for a site to attract a lot of attention (and clicks) but never do anything useful at all. Of paramount importance is the concept of authenticity. Genuine participation in science is essential in an era when such a thing is possible. Our mantra at the Zooniverse is that we should never waste people’s time. Now that it has been convincingly shown that the public can contribute to research via the web, it is incumbent on new web-based projects to keep the bar raised and the standard high.

We are at the beginning a citizen science renaissance online. After hundreds of years as the purview of bug-collectors and bird-watchers (all very important work, I hasten to add), we are finally able to tap into the cognitive surplus [2] and attempt truly distributed research. I’m looking forward to seeing how it can be taken to the next level – and hopefully to being a part of it.

[1] or just take a look at Zoo Teach as an example of facilitating educators rather than asking them to use your own materials.

[2] FWIW I actually prefer Shirky’s ‘Here Comes Everybody

That’s No Supermoon

June 24, 2013 — 4 Comments

The periodic mention of a ‘supermoon‘ in the news cycle is starting to annoy me. A supermoon is simply not that much bigger than any other Moon!  It’s apparently just perceptible but by no means would you call it ‘super’. Annoyingly though, observation of the so-called supermoon is wrapped up in another effect: the Moon Illusion. This means that people enthusiastically report seeing a really big Moon, but don’t realize that they would likely have thought it big on any other Full Moon night too.

So let me put my rant in some context. The term supermoon was coined by astrologer Richard Nolle about 30 years ago. It refers to a Full Moon or New Moon that occurs when the Moon is in the closest part of its orbit around the Earth. The Moon’s orbit is not perfectly circular and there is a closest point in every cycle (perigee) and a most-distant point too (apogee). At perigee the Moon is closer to the Earth by about 50,000 km (30,000 miles), which is enough to make the Moon appear slightly larger in the night sky. In fact it is about 1.1 times larger in it’s angular diameter on the sky. Expert Moon watchers can see a subtle difference but it’s pretty slight and hardly warrants the title of a ‘super’ moon.

The Moon's motion over one cycle.

The Moon going through one complete orbit as seen from the Earth.

This animated GIF shows a Moon going through one entire orbit (apogee-perigee-apogee) and you can see the changing size (you can also see it undergoing libration, which is the wobbling motion). You can a direct size comparison below. In both these cases you’re seeing it close-up – imaging these things hanging in the sky at a distance. The size change is happening in every cycle, but is most prominent when the Full Moon coincides with perigee, as was the case this week.

Size Comparison for the Moon at Apogee and Perigee

Size Comparison for the Moon at Apogee and Perigee [Source:

So there is a difference in the appearance of the Moon but it is very small and you’re unlikely to be seeing this when you go outside to look at a supermoon. What you’re actually experiencing is most likely the Moon Illusion: the optical illusion that the Moon looks larger when it is near the horizon than when it is high in the sky. The Moon Illusion is not well understood but most astronomers are very familiar with it. It may be partially caused by the Ebbinghaus illusion, which is the one that makes the two central circles in the following image appear to be different sizes when they are, of course, the same. When close to the horizon the Moon is compared to objects like rooftops, hills and clouds. When high in the sky is mostly seen in wide-open space. Another explanation may lie in the processes that govern our binocular vision; it might be that the Moon Illusion does not occur of you stand on your head, for example. This has not (yet) been tested widely.

Ebbinghaus Illusion

So what happened over the weekend was that people heard about a supermoon and so went outside to see it. Given that it any observable supermoon is a Full Moon, this means people went out to see it when it was low down in the sky, because Full Moon’s rise late in the evening. Thus they probably experienced the Moon Illusion and reported that indeed the Moon looked very large.

On a final point: the supermoon is also given silly superpowers by some new outlets too. The natural oscillation of the Moon’s distance does indeed affect tides a little, but it does not cause earthquakes, madness or werewolves.

Image Credit: Jack Newton

Image Credit: Jack Newton

There’s a cool paper on arXiv today in which an intrepid band of astronomers (I assume they were/are intrepid) search for exoplanets around the stars in the Pleiades using Subaru. Spoiler alert: they don’t find any! However, it’s an interesting look at how to hunt for planets and small/faint objects in general.

They find 13 potential planet candidates around 9 stars. 5 of these were confirmed as background stars and two more are dismissed because they either didn’t appear in all data or the data that did appear in wasn’t good enough. Two more were found to be known brown dwarves, with masses 60x the size of Jupiter. The remaining 4 candidates still await further data to confirm their motion across the sky – but aren’t though to be planets either.

By not detecting any planets with a very sensitive instrument they are able to estimate an upper-limit for the frequency of such planets around stars in the Pleiades. So by not finding planets, they learn something really interesting. Well done, science.

The response my previous blog post about gender bias took me by surprise. Apparently if you talk about this stuff openly, people have a lot to say. More than 500 people have read the post on this site and more over at the Women in Astronomy blog.

After posting it, I also emailed the upcoming .Astronomy 5 attendees and offered everyone (men and women) a second shot at sending in a talk abstract. As many men as women sent me an abstract in the following few days – come on: that’s kinda funny, right? The result is that I believe we can now create a more equal speaking line-up for September’s event, and I’ll be inviting speakers soon*.

I’ve also had a lot of feedback from Twitter, Facebook and other places, with stories of both very different and similar experiences. Many people seem to think that .Astronomy is unusual and that may put women off more than men. I find that hard to believe, but I’m willing to consider it. Mainly, people wanted to know how the sign-up form was worded, so here it is:

I don’t see anything here that one would consider biased. I can’t say the same for the .Astronomy sign-up form that Chris Beaumont  found in this tweet.

It’s been suggested that I ask the women who didn’t sign up, why they didn’t. Honestly I’m not comfortable doing that – but if any of them want to volunteer a response that would be interesting. I’m also not sure that anyone can really even be aware of the things that may bias them toward submitting a talk abstract (or not) when they fill out a form.

Finally (for this update) I’ll point you to a very interesting URL that several people shared with me this week: the AAS Committee on the Status of Women’s page detailing the ‘Percentages of Conference Invited Speakers Who Are Women‘. It shows that .Astronomy is not so unusual and that astronomy is very much still male-dominated. Are we surprised? No. Can we change this? Yes. The question is: how? That’s what I’m going to be asking a lot when we create the sign-up form for .Astronomy 6.

I’m really pleased with how this has turned out, and look forward to a more balanced and awesome .Astronomy 5 in September. I really appreciate everyone’s feedback and I think this conversation will keep going – so I’ll posts updates if necessary.

*Hurray for blogging!

We’re running the fifth .Astronomy conference later this year in Boston. .Astronomy is a small (and awesome) conference for astronomers, where you must apply to participate. Although the tone is relaxed, spaces at the event are in short supply (there are only 50 places). You don’t have to talk at .Astronomy, and there are only a few speaking slots, but it’s a pretty friendly crowd and you can talk about a wide variety of things. So why did only 2 women submit an abstract (out of 27 female applicants) versus 30 men (out of 65)?

.Astronomy 5 Signup Gender Ratio

We would like to create a broad group of speakers but it’s hard to select talks that don’t exist. Did we inadvertently create a bias toward male speakers by soliciting abstracts on the sign-up form? If so, that’s a worry because it’s how a lot of conferences do this.

To be clear: on our simple conference registration form, almost 50% of men submitted an abstract, but only 7% of women. Holy moly.

There has been a great deal written about the fact that women lack self-esteem, relative to men. This explains some of the gender gap in pay, promotions and even published op-eds. This isn’t news, really. In fact the 7% and 50% figures above are eerily close to the percentages for each gender who negotiate starting pay after getting an MBA – and that study is more than 10 years old!

.Astronomy Signup Gender Gap

What is news to me is that we committed the same error at a progressive conference in 2013. Does this mean that conference registration forms like the one used for .Astronomy are an example of unwitting bias against women in astronomy – and who knows: science, academia, conferences in general?

I’d be interested to know how this plays out at other conferences and events. Do the UK National Astronomy Meetings see a similar gender gap? Do AAS Meetings? Does anyone else have anecdotal examples of similar or contradictory things happening?

I realise that there are women with plenty of self-confidence – and also men who lack it. I also realise that self-confidence does not correlate with academic ability and so perhaps we need a better system for selecting people for talks, promotions or jobs. I’m not proposing any solutions here – that would be extremely self-confident of me. What I do know is that whatever system would improve the situation, it will also be important for the women of academia to boldly go where statistically fewer women have gone before: and submit more abstracts.

As for .Astronomy: if you’re coming to the meeting in September and you’re a woman who didn’t submit an abstract (there are many of you!) then feel free to email one to me now. The SOC are still picking a range of speakers and talks, so we’d love to hear from you.

[There’s a follow-up post to this here]

A recent APOD featured this beautiful video of the Northern Lights over Norway. The opening shot is almost exactly how I saw the aurora in 2012. The Sun is at the peak of its activity and therefore the likelihood of seeing aurora (at either pole) are increased at the moment.

The Apollo astronauts narrowly avoided serious health problems, and even death due to exposure to radiation from the Sun. Here’s a plot of the approximate Solar proton flux during the Apollo era:

Here’s the same but with the missions and health warnings labelled:

Scary stuff! I made these images for a talk I gave a while ago, inspired by @DrChrisDavis and using data from WOTM. Just found them and thought I might as well post them up.

Yesterday I toured the site of ITER, the nuclear fusion plant under construction near Cadarache, France. A multinational collaboration is pumping 150 billion Euros into this experimental fusion reactor, which aims to create 500 mega-watts of power, for every 50 that are pumped into.

ITER, which sort of means International Thermonuclear Experimental Reactor but is actually just a nice, trans-national word, is an enormous project spanning generations. First conceived in the 1980s, the idea is to create mostly clean, virtually limitless energy through the process of fusing Hydrogen atoms together. This is a process we see at work in the universe in stars and it seems technologically feasible that with a lot of work we can reproduce the conditions on Earth and set ourselves free of not only a limited fossil fuel supply, but also of the cost of using those fuels long term (i.e. climate change).

ITER grew as a collaboration during the 1990s and the decision to locate the experimental plant in France was made early in this century. Europe currently funds the bulk of the project (45%) with Russia, Japan, Korea, the USA, China and India all participating in other major roles, currently they are building many of the reactor components.

The ITER fusion reactor at Cadarache is purely experimental, it will never be used to generate energy for the French grid. The site chosen was a 180 hectare forest and 90 hectares of it will remain as such, to surround the site and keep it looking green. The site is also somewhat seismically active, and earthquakes can occur here. The structure is being built to withstand a 7.2 Richter magnitude earthquake, though such an event has never been recorded in the area, with the biggest being. 6.1 quake over a hundred years ago. To accomplish this the whole site is being built atop 500 special columns, that allow the entire facility to pitch and bend during tremors. It is all very impressive.

ITER is due to be completed in 2020, at which point full-scale nuclear fusion experiments will begin. The reactor itself is a Tokamak: a donut-shaped ring of plasma, contained within intense magnetic fields. This plasma reaches temperatures of 150 million degrees (10 times as hot as the Sun!), and incredible pressure. Under such conditions it is believed that fusion can occur at large scales. Large is necessary in this game, and the aim of the project is to be able to output 10x as much energy as was input to the reactor. Such a multiple of energy return makes fusion a viable power source for the world, and in this case will mean transforming 50 mega-watts into 500.

After 25 years of experiments, the ITER project will be complete and a second reactor will be built, based on the results of the research done in Cadarache. This second reactor, DEMO, will be a functional power station and will lead the way for widespread nuclear fusion for the world.

If all goes according to plan it will have taken a little over a century for the dream of nuclear fusion to become a global reality.

Today, that dream is very much still under construction (see photo below). The place is mostly a levelled building site. A couple of the buildings have gone up, and the power grid is in place. It would be good to return and tour it again in a few years.

One amazing fact about ITER has stood out for me in particular: after the experiments are complete, the whole site will be deconstructed and the location will be turned back into forest.

This decision seemed utterly bizarre to me at first. After thinking about it though, I’m not sure how else you can responsibly plan for something as long term and large-scale as ITER. A century from now, it is hard to know if fusion will have turned out to be the best route to take and rather than leave our descendants with an ageing reactor to deal with, at least this plan means we leave things as we found them. Also, since the successor to ITER (DEMO) is part of the larger plan, it seems prudent to factor in the concept of cleaning up phase 1 as phase 2 ramps up. Perhaps this is how more big ideas should be planned? On the other hand, it seems ridiculous that the first industrial-scale fusion reactor will never be used for civil energy generation, and will not be kept for even the sake of history.

Learn more about ITER here and here.

Olbers’ Paradox

April 19, 2012 — Leave a comment

Wendy Sadler (of Science Made Simple fame) was asking, on Facebook, what explanations people usually gave for Olbers’ Paradox. The slew of answers from several people revealed that the canonical answer is not the only one people think of.

The paradox is named for a 19th Century astronomer, Heinrich Olbers, who remarked that if the universe is infinite, and there are stars throughout it, then in whatever direction you look you would be looking at an infinite number of stars and the night sky would therefore be as a bright as the surface of the Sun. This is not what we see, so why is the night sky dark?

I have always thought that Olber’s paradox is resolved by two ideas. Firstly, realising that the Universe has not existed forever, so you do not look infinitely far into the distance. Then there is also the fact that the Universe is expanding, and stars move faster from us the further you go back, and their light is redshifted beyond our vision.

Another common answer is that the Universe may be full of stars, but it is also full of dust and gas. This blocks some of the light. I don’t think this really does help solve the paradox. If there were infinite stars illuminating the dust, the dust would end up glowing itself. Also if the sky were as bright as the surface of the Sun, you’d need an awful lot of dust – by comparison, you’d need to put a huge amount of dust between us and the Sun to block it out.

In looking into this further, I discovered that Edgar Allan Poe was one of the first to suggest that the resolution to the problem was that the Universe is not infinitely old. In 1848 he wrote Eureka, which contained the following:

Were the succession of stars endless, then the background of the sky would present us a uniform luminosity, like that displayed by the Galaxy – since there could be absolutely no point, in all that background, at which would not exist a star. The only mode, therefore, in which, under such a state of affairs, we could comprehend the voids which our telescopes find in innumerable directions, would be by supposing the distance of the invisible background so immense that no ray from it has yet been able to reach us at all.

Lord Kelvin is attributed to the best, correct response in 1901. More curiously it turns out that it is not necessarily Olbers’ paradox at all. The problem was first noted 300 years earlier by Thomas Digges and was also expounded by Kepler.

On a final corrective note, it was only when I Googled a bit for this blog post that I realised Heinrich’s surname is Olbers and not Olber, thus moving the apostrophe in an already misnamed paradox.