Five years ago, the Internet changed forever. It wasn’t really a landmark development – no outstanding advancement in modern technology, or a breakthrough in medical science. It was simply a humble picture of a dress with a simple question; what colour is this?

And it kicked off a global slight panic with the discovery that hey, not everyone sees things the same way. Truly mind-blowing stuff, people.

Far greater than the routine squabbles about location-based language (it’s a potato cake, don’t argue), the argument that tore the Internet apart was about what the fuck the colour of this dress is.

For some, they saw white and gold. For others, like me, it’s more blue and black. Sometimes I see blue and gold. I think. The colours literally change the more that I stare at the picture.

The argument bubbled its way to Hollywood, with plenty of celebs weighing in on what colour the dress is.

(That’s a classic Ryan and Kelly argument right there, I swear it.)

It all comes down to the science of sight. Speedy researchers worked on figuring it out from a scientific perspective and published their findings a couple of months after the dress destroyed the Internet. As per Live Science, they determined that it’s all about how our eyes perceive colour in daylight.

They found that people who saw the dress as white and gold probably assumed it was lit by daylight, so their brains ignored shorter, more blue wavelengths. Those who saw the dress as blue and black assumed a warm, artificial light, so their brains ignored longer, redder wavelengths. And finally, those who saw the dress as a blue and brown colour probably assumed neutral lighting.

Science aside, I can assure you it’ll spark up plenty of debates again this week as we look back at the exact moment offices, workplaces, group chats, classrooms, and any significant gathering of people absolutely went to pieces over a god damn dress.

In reality, though, the dress is blue and black (though they did produce a one-off gold and white one and auctioned it off, raising over $5k for Comic Relief.)

But hey, at least one person got it right: Chrissy Teigen.

Image: Tumblr / Twitter / @OodoriSummer