‘Could we be aided in this matter by the cooperation of a goodly
number of amateurs, ‘we would perhaps in a few years be able
to discover laws in these apparent irregularities, and then in
a short time accomplish more than in all the 60 years which
have passed since their discovery. I have one request, which is
this, that the observations shall be made known each year.
Observations buried in a desk are no observations. Should they
be entrusted to me for reduction, or even publication, I will
undertake it with joy and thanks, and will also answer all
questions with care and with the greatest pleasure.’*
It is a fabulous call to arms—‘observations buried in a desk are
no observations’ would be a great motto for some society or
other.† I love the sense of a deal being struck between those
taking the observations and Argelander himself. On the one
hand, we have the (presumably unfunded) volunteer with their
telescope. On the other, an eminent professional scientist. Data
can be passed from the former to the latter—but only if
Argelander too puts his back into it and makes use of the data.
* Translation by Annie Jump Cannon in Popular Astronomy, 1912, from an original in the Astronomisches Jahrbuch of 1844.
† To my mind, greatly preferably to the Royal Astronomical Society’s motto, adopted from Herschel: ‘quicquid nitet notandum’, or ‘whatever shines, let it be observed’. Science teaches us that the real work is only beginning when observations are written down. The American Astronomical Society has a mission statement, not a motto.
No Such ThiNg aS a New ide a 99
Oh, and part of the deal is that he has to communicate results
and answer questions from his observers.
It seems important that Argelander is offering more than a
oneway exchange. As far as I know this is the first example of a
professional scientist so explicitly writing about the give and
take of this way of collaborating to get science done. As Galaxy
Zoo took off, I certainly felt the obligation to try and respond to
questions, though I can’t claim to have always faced the task ‘with
the greatest of pleasure’. What is also reflected in Argelander’s
work is a somewhat formal division of responsibility; observation can be safely distributed, but analysis is specialized and central. One can argue about which is primary (and whether Darwin was being deliberately or falsely modest when referring to himself as a mere ‘compiler’), but there is a settled order here.
This way of organizing things was effective, and it enabled
Argelander to work on a scale that was inaccessible to astronomers
of previous generations. The catalogue Argelander and colleagues put together contained the details of more than 300,000
stars, and was the definitive work of prephotographic stellar
astronomy, at least for the northern hemisphere. It remained in
use for years, and his categorization of variable stars remains the
standard today. If you visit the astronomy facilities in Bonn,
you’ll find that in 2006 they were renamed the ‘Argelander
Institute’ in his honour; a recognition, I’d like to think, of the
power of asking for help.
Networks of amateur astronomers survive too. Data on stellar
variability, especially on timescales of decades or more, depend
on the catalogues assembled by the American Association of
Variable Star Observers, an organization with worldwide reach
whose observers have assembled more than twenty million
records since its founding in 1911. Rainfall observers may not,
these days, form extensive networks but the Audubon Society’s
100 No Such ThiNg aS a New ide a
Christmas Bird Count is still going strong. This annual birdwatching festival has been operating since 1900, having been introduced partly for scientific interest and partly as an alternative to the then common tradition of marking the holiday with competitive hunting. In the UK, biological recording of the presence or absence of species depends on a network of societies, many of them dating from the late nineteenth or early twentieth
century, with specialisms ranging from orchids to the British
Pteridological Society (ferns, since you ask).
Twentyfirstcentury researchers are fond of pontificating
about the problems caused by big data, the sudden flood of digital information among which we struggle to pick out signals of interest. Yet the appearance of modern instruments and vast networks of the kind described above caused an earlier deluge of data, and brought a very different set of people into the scientific
enterprise. These were the first ‘computers’, people rather than
machines, and they soon accounted for the majority of staff
employed at observatories.
The job of ‘computer’ was established at the Royal Observatory
in Greenwich, for example, as early as 1836, and survived until
1937, a little more than a century. Their arrival broke the tradition by which it was the Astronomer Royal and his specialist assistants
who did the work to make their own observations useful, and the
staff quickly grew. The original computers, working eight hours
or more a day at tedious and repetitive calculations, were
recruited by looking for poor but bright students from local
schools. However, as the century wore on it became clear that
this was nothing more than a stopgap solution; the wages were
abysmal and the work tedious, and with little prospect of promotion most computers moved on. By 1890 the Greenwich staff had hit on the idea of solving this by employing women who had
university experience; such staff would be skilled enough to
No Such ThiNg aS a New ide a 101
work as more than a mere calculator, but would lack other
opportunities for scientific participation.
The papers which record the decision to employ women
explicitly make clear that it was felt that Greenwich could take
advantage, attracting to this often menial job women whose scientific opportunities would otherwise be lacking. If that was the marketing scheme, it was not a success. Though women continued
to be employed at Greenwich, opportunities for promotion were
gradually opened up for men, and those with qualifications
(most often a degree) began to take up what had once been junior
and menial posts, seeing them as a stepping stone to higher
things. The women were once again squeezed out of even this
small foothold in the scientific enterprise.
For a time, though, the position of these functionaries allowed
a different sort of engagement with scientific data. What sorts of
jobs were these human computers undertaking? Most of the
work at Greenwich was positional astronomy, and results would
be recorded in the form of measurements which were straight
from the telescope, perhaps as a distance between two stars.
These would have to be converted to some standard reference
frame, and celestial coordinates assigned. Systematic effects like
the influence of the Earths’ atmosphere, which varies with the
height of a source in the sky, must be accounted for. Even once
that’s done, single observations of a typical star are hardly going
to carry much information, and catalogues must be compiled
and crosschecked, and global properties derived.
These c
alculations are the very stuff of which science is made,
but just as with Argelander and his observers we see in the existence of the computers a division of responsibility. Observers—
whether employees or volunteers—provide data. Computers do
the processing, turning tables of data into results; the two are
even separated by time, with observers producing data during
102 No Such ThiNg aS a New ide a
the night that can be processed by computers during the day,
before being studied by scientists who publish their results. Each
subsequent stage of analysis depends on the former—indeed, it
could hardly exist without it—but only the later stages are visible
to the wider world. We celebrate the scientist who interprets the
observation, not those who made it possible.
None of this is news, at least not to the accomplished historian
or sociologist of science. You, my sophisticated reader, don’t
need me to tell that the real story of how science has proceeded
over the centuries is more complex than the standard procession
of dead, white, bearded men with theories might suggest, and
this chapter hasn’t tried to do more than offer a potted set of
anecdotes. These stories do, however, illustrate that right back at
the time when our modern notion of what it meant to be a scientist was being established—when we had a much more fluid idea of what science was than has been the case for most of the last
century—it is possible to trace disputes about status, about the
correct division of work between the classes of those involved in
research. Back in the twentyfirst century, we set up Galaxy Zoo
to get work done. It soon became apparent that the real power
and interest of the project lay in thinking about precisely these
issues, and that began with volunteers doing more than just
clicking on buttons to classify galaxies.
4
INTO THE ZOONIVERSE
Looking back at the early days of Galaxy Zoo with more than a
decade’s perspective, it seems to me to be a strange and
marvellous thing, this idea that so many people would give up
their time to collectively contribute to science. Occasional critics
carp that classifying a few galaxies isn’t participating in science—
that the claim to have done science should be reserved for those
who designed and set up the project, and who interpret the
results.
As I said in the last chapter, I’m less dogmatic. Any scientific
project rests on the contributions of many people, whether it’s
those who operate the telescope up on a lonely mountain top or
people like me, whose daily life is much more likely to involve
emails and admin than a ‘Eureka’ moment. I know the Galaxy
Zoo crowd have done science, because there’s an ever-growing
pile of academic papers with new scientific results within that
wouldn’t have existed without them.
Better still, the ideas in those papers have been adopted and
echoed by the rest of the community. We were even thrilled
when people started to use our results without pausing in their
texts to dwell on ‘citizen science’, taking it as a sure sign that we were producing data of a high-enough quality that authors
104 Into the ZoonIverse
didn’t feel the need to justify or explain their use of it. (Things
took a slightly odder turn when two philosophers wrote a
paper which, while calling for ‘a sociotechnological turn in the
philosophy of science’, which I’m afraid to say you’ll have to
read about elsewhere, compared the rate at which Zooniverse
papers were cited to others using the same data. Apparently we’re
as a group as productive as a world-leading research institute.
Nice to know!)
The downside is that, all this time later, it’s rather difficult to
briefly summarize what we’ve found. Galaxy formation is messy,
and that messiness—the fact that many different things control
how galaxies first form and then change over billions of years—
makes a nice, clean story hard to find, at least for now. That’s
what science is like sometimes, even if it makes writing a book
chapter harder. So, instead of trying to present a comprehensive
view, let me tell you a couple of stories that will give you an idea
of the kind of thing we’ve been able to do with the results from
Galaxy Zoo.
One problem we’ve tried to attack is to try and understand
what happens when two galaxies collide with each other. Merging
like this certainly seems important. The early Universe was filled
with scrawny protogalaxies, each less than a hundredth the size
of a typical galaxy today, and these seem to have, over the long
span of cosmic history, gradually collided and merged to form
larger and larger systems. This process isn’t finished yet—the
grand collision of the Milky Way with Andromeda that I men-
tioned earlier isn’t due to happen for another four or five billion
years’ time, but when it does happen, our computer simulations
make it clear that it’s likely to be a spectacularly messy and dis-
ruptive event.
When two large galaxies like these collide with each other, a
cosmic ballet ensues. The first approach sees the galaxies fly past
Into the ZoonIverse 105
each other, their mutual gravitational attraction distorting their
previously neat discs and creating long streams of stars (Plate 6).
These are tidal tails, unstable creations of the merging process,
and as they begin to fall back towards the main body of each gal-
axy the two discs turn and plunge back together once more.
This repeated encounter creates new distortions, and further
disruption as the merging system takes on a wide variety of
forms. We can see this stage of the process in nearby galaxies,
whose names conjure up appropriate images—the ‘Antennae’,
with two long streams stretching away from a bifurcated body
the ‘Mice’, imaged beautifully with the Hubble Space Telescope, with long tails revealing a recent interaction. Such a stream has even
been spotted stretching between Andromeda itself and the third
large member of our Local Group, M33.
Apart from being flung out of orbit, stars which formed before
the merger will continue as they were before; even within a gal-
axy of a hundred billion stars like the Milky Way, there is enough
space in space to make a collision between two stars during a
merger vanishingly unlikely.
That’s not to say we shouldn’t expect fireworks when the Milky
Way and Andromeda collide. Gas clouds do collide with each
other and the result is a spectacular boom of star formation. The
Earth may not be the best place to watch, as the Sun will by then
have entered its red giant phase and swallowed our home,* but if
you can make it to a suitable planet then you should expect a
spectacular night sky, speckled with newly formed and brilliant,
* I may be being unfair to the Earth’s prospects as a long-term observing platform. As the Sun converts hydrogen to helium it loses mass, and, because of the law of conservation of momentum, our planet spiral
s slightly outwards. There is therefore some chance that the Earth may survive the Sun’s swelling into a red giant, though how reassuring you find the chance of our planet’s future existence as a charred cinder is perhaps a matter of personal taste.
106 Into the ZoonIverse
massive stars. The view from inside what’s called a starburst
galaxy must be absolutely wonderful.*
Though such a spectacular rate of star formation most likely
can’t be sustained, the long-term effect of a merger might be to
change the shape of the colliding galaxies for ever. In the case of
the collision between the Milky Way and Andromeda—two
discs—the result according to most simulations is their trans-
formation into an elliptical.
This makes a certain amount of intuitive sense; discs are
ordered systems, their stars orbiting in concert around their
centre, and a serious disruption will see stars kicked up out of the
disc and into the more random pattern of movement which char-
acterizes ellipticals. A new, unified galaxy is produced (what
some researchers insist, despite everything, on calling Milkomeda
or—hardly better—Milkdromeda), larger and more massive
than before and ready to continue life as a stereotypical elliptical.
Perhaps the last stage of such an event takes place deep
inside the new galaxy, at its core, as the supermassive black
holes that previously inhabited the centres of the constituent
galaxies dance slowly around each other, losing energy in the
form of gravitational waves and spiralling inwards, eventually
merging. A small number of galaxies are known that have
double or even triple black holes at their centres; though they
look otherwise undisturbed, these are most likely the products
of recent mergers.
Galaxy Zoo must contain many such galaxies, observed a
few billion years after the end of the merger. Can we tell, just by
looking at the galaxy, that anything spectacular had happened?
* Of course, the odds of your planet being blasted with lethal radiation from a nearby supernova is greatly increased in such a system. One can’t have everything.
Into the ZoonIverse 107
The tidal tails of stars flung from the centre of the system will
The Crowd and the Cosmos: Adventures in the Zooniverse Page 13