It is, quite possibly, the greatest mystery of our time.

No, not what happened to that Malaysia Air jetliner.

No, not how those sliding stones in Death Valley move themselves across the desert.

Not even how those llamas escaped their enclosure and went on the lam (sorry) for a few hours in Arizona last week.

I’m talking about the dress.

The dress that everyone else is talking about.

The dress that broke the Internet.

It all started on blogging site Tumblr last Thursday when a user posted a picture of a dress that a woman would be wearing at a wedding later that day.

The poster said she and her friends could not agree on the colour of the dress.

But it wasn’t the typical pink-or-purple, green-or-blue mixup involving certain colours that can be identified as either.

No, the poster thought the dress was gold and white, while her friends saw it as black and blue.

The Internet came alive with cheesy jokes about beating the idea of the colour of the dress black and blue, and soon enough, it went viral and there were dozens of online explanations.

They ranged from the cynical and simplistic (they are two different dresses, simple as that) to very unscientific online polls in which more people reported the dress in the photo to appear white and gold.

Then there were more complicated ideas relating to the ability of the brain to perceive colour in relation to the colours around it.

The theory goes like this: the picture originally posted of the dress was super washed out in the background, meaning it was extremely lightened on a yellow-tinged background. The parts of the dress which appeared white (to some) were actually blue, and the blueish undertone was more evident to some others.

Each person perceives colour in part by a degree of contrast, and there is huge variety in the way people process this contrast.

The photo of the dress on a hanger before the wedding appears white and gold to about half of the people who look at it.

But there’s no debate about the colour of the dress as it appears on the mother of the bride in photos taken at the wedding later that day. It’s a blue dress with black lace.

Another explanation posits those who see the dress as white and gold are subconsciously seeking the details in the black lacy bits, and so that gets most of their focus and the overall colour scheme of the picture converts the black to gold. Without being the primary focus of the photo, the blue parts are then blown way out as to appear white.

Those who unconsciously focus more on the smoother, skinny tiers of the dress’ material see it for the true-blue dress it is.

It’s a one-in-a-million shot that gives us a glimpse into how complicated colour processing really is. How we are able to do all of this without being aware of it is the real mystery.

Some people reported seeing the dress as the different colour schemes at different times of day or under different lighting conditions.

No matter how many times I looked at it, I couldn’t see it as anything other than white and gold, which is fine by me.

I thought the dress looked nicer in white and gold than blue and black anyway.