Current estimates put the number of stars in the Milky Way at well over 100 billion, each of which is thought to have at least one planet in its orbit. Assuming at least some of these planets have given rise to intelligent life capable of communicating with Earth, why haven't we heard from them yet?

Cosmological questions like these form the the basis of Enrico Fermi's eponymous paradox, and helped give rise to the Drake equation. It's also the starting point of the latest installment of It's Okay to be Smart, wherein Joe Hanson examines the similarities in the odds of finding life in the Universe and the odds of finding love, here on Earth. After all, love is universal, and there are billions of people looking for it — but it can often feel very hard to find.

We're loving the number crunching in this episode (not to mention the Sagan cameo). Hanson is essentially using order of magnitude estimation to solve what's popularly known as a Fermi problem (yes — the same Fermi as Fermi's paradox). Fermi, it so happens, was renowned for his ability to come up with surprisingly accurate guesses for seemingly overwhelming estimation problems — that includes estimation problems *other* than the number of intelligent lifeforms in the Universe.

When we first watched this, it reminded us a lot of the "Drake Equation of Love" that this British Mathematician used in 2010 to determine he had a 0.00034% chance of getting laid. But it turns out people have been using Drake-esque equations to this end for some time. Computational linguist Tristan Miller did it back in 1999. This American Life did it in 2009. Shoaib Malik wrote a poem about it. Even The Big Bang Theory's had a go at it. It's like some bizarre rite of delightfully geeky exoplanetary passage. For Hanson's part, he's carried on the tradition with updated, more modern variables (like statistics on the number of people who date online).

We recommend pairing this with this newly released TED-Ed video on OKCupid's matching algorithms, narrated by the online dating site's co-creator, Christian Rudder.

## DISCUSSION

Unlike the Drake Equation, the Love Equation is almost certainly missing several key factors and the estimates of many of these later factors are highly subjective I think. This high level of subjectivity makes it a very unfair comparison in my opinion.

At least Drake's latter factors can be addressed in a objective way with sufficient evidence.