DT Next Campus: Social network is a bunch connected by relationships, like dots linked by lines
Invisible web of friendships follows rules like the laws of physics
Prof Mahesh Panchagnula
CHENNAI: Have you ever wondered how people are connected? Think about your school or college. You might have a few close friends, and they have their own friends, and soon enough, you find you’re connected to kids you’ve never even met! This invisible web of friendships is what we call a social network, and believe it or not, it follows rules — just like the laws of physics.
We all see how some kids in school are super popular, while others know only a few people. What if I told you that the way friendships form in your school — and even how connections work on the internet or in nature — can be explained using the mathematics of social networks called graph theory?
A social network is simply a bunch of people (or things) connected by relationships, like dots linked by lines in a web. Scientists discovered in the 1990s that social networks, the World Wide Web, and even airport connections all share a surprising pattern: most people (or airports, or websites) are connected to just a few others, but a tiny number are connected to many, many others.
These super-connected ones are called hubs. Networks with lots of small players and a few giants — such as the friends network on Facebook or Instagram — are called scale-free networks, because this pattern stays the same no matter how zoomed-in (or zoomed-out) a view you take of the network.
Two scientists, Albert-László Barabási and Réka Albert, explained how these hubs form. In their Barabási–Albert model, new nodes — like people or websites — prefer to link to those who are already popular. This is called preferential attachment: the rich get richer! Scale-free networks are tough against random breakdowns — if a few random nodes disappear, the network still holds together—but if a hub goes missing, big parts can fall apart.
So the next time you send a friend request or share a viral meme, remember that the universe loves building connections in surprising ways, and that physics and math help explain these living and growing networks..
Authored by Prof Mahesh Panchagnula, Head of Centre of Excellence on Sports Science and Analytics, IIT Madras Faculty in Department of Applied Mechanics and Biomedical Engineering, IIT Madras