From Titan's Doom Mons to Mercury's Pourquoi-Pas: how did the landscape of space get its names?

A detail from Ordnance Survey's new map of Mars. Image: OS.

The Ordnance Survey recently made a very nice map of Mars’ Arabia Terra region. This map shows an alien crater-pocketed landscape, peppered with mysterious names like “Aram Chaos”, “Meridiani Planum” and “Marth”.

When the OS makes a map of Britain, it is making a map of a place with history – reflected in place names that come from the many different languages that people have spoken here. But where are the names on the Mars map coming from?

The romance of naming

Space used to be like the Wild West, with different names used by different people. So, in 1911, the International Astronomical Union started to become the official clearing house for space names.

It legitimised features from previous maps (like Schiaparelli’s map of Mars) and made rules for how new names would be picked. It now publishes its database online, and I used this and various NASA maps of other planets to build We Name The Stars – a way of exploring these rules and places.

The IAU conventions seem to understand that there is something magical and important about naming things. We don’t end up with Crater 62 on asteroid BXM-2: each kind of feature (mountains, ridges, craters, lakes) on each different world has a different naming convention, so that similar places are thematically linked. Often revolving around a particular ancient myth, this lends a sense of grandness and history to what is otherwise just some slightly different coloured pixels.

A screenshot from the "We Name the Stars" page on Mars. Click to expand.

Not all names are mythical. Craters on Mercury are named after historically significant artists, while escarpments are named after ships of discovery. This is how you end up with a slope on Mercury named “Pourquoi-Pas”.

Craters on the asteroid Eros are named after “mythological and legendary names of an erotic nature” (which gives us Casanova and Abelard), while Saturn’s moon Titan has places named after mountains in Middle Earth. The largest mountain on Titan is called Doom Mons.

Places We’ll Never Go

Part of the appeal of the OS map is that it reinforces the idea of Mars as a place. It’s a technical challenge, but ultimately we understand how we’d get there, walk around, and get back.

Similarly you can vaguely imagine the 22nd century equivalent of the Arctic Explorer taking the journey my virtual rover is making across the Moon, visiting every crater. But there are plenty of other places to which we’ve given names that will probably never be walked on by people.

Take Mercury – it’s right next to the sun and spins very slowly. Every place on the planet spends every other month staring into the furnace. In several of his books Kim Stanley Robinson solves this problem with Terminator – a city that travels on rails around the planet. The sun heats the rails, which expand and push the city onward – permanently keeping it just beyond dawn.

But this is a fragile solution. Valleys on Mercury are named after ancient abandoned cities – a poor omen for the success of future settlement. Maybe maps of Mercury are for visitors, driving slowly to stay ahead of the sun.

 

A screenshot from the "We Name the Stars" page on the Moon. Click to expand.

Venus we can’t even visit. In the day the surface can get hot enough to melt lead, and the atmospheric pressure is the equivalent of being a kilometre under the ocean on Earth. On the other hand, it turns out that, if you build floating cities 50km up, the pressure and temperature are pretty much the same as on Earth. To our cloud-dwelling descendants it’ll probably seem odd that we put so many of our goddesses on features as unimportant to them as the floor of the ocean is to us.

There is something strange and wonderful about a system that produces such evocative names for places that in all likelihood no one will ever visit. These names don’t have to be pretty or coherent – but the effort is made anyway.

The European Sky

The IAU was founded at a time when “international cooperation” mostly meant “European cooperation”. The conventions emerging on using old myths and Latinised names were good, because that seemed like common ground.  Astronomers looked into space and then looked back on their shared classical heritage, pillaging the myths of the Romans and Greeks for important sounding but politically neutral names.

Except, of course, it’s not really neutral because not everyone comes from that heritage. Some 60 per cent of feature names are European in origin, and so European myth and history punches a little above its weight in the space naming race.

As the composition of the IAU has changed over time, this shift has been reflected in patterns for future names. Many conventions are now ecumenical: Io is littered with thunder and sun gods from different cultures, and Ceres has features named after the “agricultural festivals of the world”. Rhea uses names from “people and places from creation myths (with Asian emphasis)”; names on Triton are explicitly “aquatic names, excluding Roman and Greek”.


Fragile Monuments

But these are all faraway places, what about European domination of the places we’re actually likely to go – like the Moon and Mars? If the future of space turns out to be non-western, this issue ends up solving itself.

After the Chinese Yutu rover landed on the moon, the landing site was named Guang Han Gong (Moon Palace) and three local craters were given names from Chinese astrology by the IAU. When the asteroid 1998 SF 36 was selected as the target for the Japanese Hayabusa spacecraft, it was designated Itokawa after a Japanese rocket scientist. Where robotic feet go, naming rights follow.

On the Moon there are areas where naming is reserved to honour dead astronauts and cosmonauts, with the ominous note that “this convention may be extended if other space-faring countries suffer fatalities in spaceflight”. And why not? There’s plenty of Moon left, thousands of craters have been identified that have yet to receive an official name.

And even if a feature has a name with a history, will people honour it? Will a Martian Chinese colony in the Rutherford Crater still call it Rutherford? Will Indian settlers in Inuvik keep the name of a small town in Canada – or rename it something closer to home?

There’s a long history of name changes in space. British astronomers carried on with George’s Star (chosen by the discoverer of the planet to honour George III) for many years after everyone else switched to “Uranus”. The Galilean moons were once the ‘Medician stars’ – after the family whose patronage Galileo sought. When Cassini discovered the moons of Saturn he called them ‘the stars of Louis’ after King Louis XIV, hoping to create “a Monument much more lasting than those of Brass and Marble”. That we don’t use any of these names reflects the fragility of monuments that only exist on paper.

European myths may end up the Lingua Franca of empty places – only kept for areas to which no one has any interest in going. If in the future there are settlers in Arabia Terra, that OS map might be an interesting historical artefact for them – a perfectly correct map with all the wrong names. 

You can learn more about space names over at We Name The Stars

 
 
 
 

Tackling toxic air in our cities is also a matter of social justice

Oh, lovely. Image: Getty.

Clean Air Zones are often dismissed by critics as socially unfair. The thinking goes that charging older and more polluting private cars will disproportionately impact lower income households who cannot afford expensive cleaner alternatives such as electric vehicles.

But this argument doesn’t consider who is most affected by polluted air. When comparing the latest deprivation data to nitrogen dioxide background concentration data, the relationship is clear: the most polluted areas are also disproportionately poorer.

In UK cities, 16 per cent of people living in the most polluted areas also live in one of the top 10 per cent most deprived neighbourhoods, against 2 per cent who live in the least deprived areas.

The graph below shows the average background concentration of NO2 compared against neighbourhoods ranked by deprivation. For all English cities in aggregate, pollution levels rise as neighbourhoods become more deprived (although interestingly this pattern doesn’t hold for more rural areas).

Average NO2 concentration and deprivation levels. Source: IMD, MHCLG (2019); background mapping for local authorities, Defra (2019).

The graph also shows the cities in which the gap in pollution concentration between the most and the least deprived areas is the highest, which includes some of the UK’s largest urban areas.  In Sheffield, Leeds and Birmingham, there is a respective 46, 42 and 33 per cent difference in NO2 concentration between the poorest and the wealthiest areas – almost double the national urban average gap, at around 26 per cent.

One possible explanation for these inequalities in exposure to toxic air is that low-income people are more likely to live near busy roads. Our data on roadside pollution suggests that, in London, 50 per cent of roads located in the most deprived areas are above legal limits, against 4 per cent in the least deprived. In a number of large cities (Birmingham, Manchester, Sheffield), none of the roads located in the least deprived areas are estimated to be breaching legal limits.

This has a knock-on impact on health. Poor quality air is known to cause health issues such as cardiovascular disease, lung cancer and asthma. Given the particularly poor quality of air in deprived areas, this is likely to contribute to the gap in health and life expectancy inequalities as well as economic ones between neighbourhoods.


The financial impact of policies such as clean air zones on poorer people is a valid concern. But it is not a justifiable reason for inaction. Mitigating policies such as scrappage schemes, which have been put in place in London, can deal with the former concern while still targeting an issue that disproportionately affects the poor.

As the Centre for Cities’ Cities Outlook report showed, people are dying across the country as a result of the air that they breathe. Clean air zones are one of a number of policies that cities can use to help reduce this, with benefits for their poorer residents in particular.

Valentine Quinio is a researcher at the Centre for Cities, on whose blog this post first appeared.