These maps guess at the connections between 24,000 of the universe's galaxies

A model of the universe. Image:barabasilab.

Scientists know a certain amount about the universe. They know that planets form solar systems around stars, which then form networks with other stars within galaxies. The universe is therefore a collection of billions of galaxies, all loosely connected by gravity in a kind of web. 

What they don't know, however, is what exactly that web – and, therefore, the general blueprint of the universe  looks like. 

Now, though, researchers at the Centre for Complex Network Research at Northeastern University have had a pretty good stab at it. Using modelling techniques and data on 24,000 galaxies, they tried out three different methods to map the connections between them. One was based the gravity connections on the distance between galaxies; one on their size; and one connected each galaxy to its nearest neighbour

The results are up on the lab's website, in the form of mind-boggling interactive visualisations which allow you to zoom and scroll through thousands of galaxies. Here's a shot of the first model, where lines represent gravitational links linking galaxies based on their distance:

The second, which gets even more complicated by linking large galaxies, even if they're further away: 

And the third:

When the researchers compared the models to known location data about nearby galaxies, they found that the third model was the best fit. This implies that galaxies which are gravitationally connected to their closest neighbours may make up the bulk of the universe’s architecture.  

Want more of this stuff? Follow CityMetric on Twitter or Facebook .


Sadiq Khan and Grant Shapps clash over free bus travel for under 18s

A London bus at Victoria station. Image: Getty.

The latest front in the row between Transport for London (TfL) and national government over how to fund the capital’s transport system: free bus travel for the under 18s.

Two weeks ago, you’ll recall, TfL came perilously close to running out of money and was forced to ask for a bail out. The government agreed, but offered less money, and with more strings attached, than the agency wanted. At present, there are a range of fare discounts – some up to 100% – available to children depending on their age and which service they’re using, provided they have the right Oyster card. One of the government’s strings, the mayor’s office says, was to end all free TfL travel for the under 18s, Oyster or no Oyster.

The Department for Transport’s line on all this is that this is about maximising capacity. Many working-age people need to use buses to get to their jobs: they’re more likely to be able to do that, while also social distancing, if those buses aren’t already full of teenagers riding for free. (DfT cited the same motivation for banning the use of the Freedom Pass, which provides free travel for the retired, at peak times.)

But in an open letter to transport secretary Grant Shapps, the mayor, Sadiq Khan, wrote that TfL believed that 30% of children who currently received free travel had a statutory entitlement to it, because they attend schools more than a certain distance from their homes. If TfL doesn’t fund this travel, London’s boroughs must, which apart from loading costs onto local government means replacing an administrative system that already exists with one that doesn’t. 

Some Labour staffers also smell Tory ideological objections to free things for young people at work. To quote Khan’s letter:

“It is abundantly clear that losing free travel would hit the poorest Londoners hardest at a time when finances are stretched more than ever... I want to make sure that families who might not have a choice but to use public transport are not further disadvantaged.”

London’s deputy mayor for transport, Heidi Alexander, is set to meet government officials next week to discuss all this. In the mean time, you can read Khan’s letter here.

UPDATE: The original version of this piece noted that the full agreement between the mayor and DfT remained mysteriously unpublished. Shortly after this story went live, the agreement appeared. Here it is.

Jonn Elledge was founding editor of CityMetric. He is on Twitter as @jonnelledge and on Facebook as JonnElledgeWrites.