Wait, Is This River Floating?

Wait, Is This River Floating?

NASA Astronaut Scott Kelly tweeted this photo yesterday, that he took from aboard the International Space Station. You can see the Bighorn River, which stretches through Wyoming and Montana… and, wait, why does it look like it’s floating?

The explanation for this optical illusion is known as relief inversion, and you may often experience it when looking at satellite photos taken in such a way that the Sun illuminates the landscape from below. This jars with our common (unconscious) expectation derived from everyday experience of the Sun shining on objects from above. Our brain finds it hard to interpret the sight.

So if you rotate the above photo 180 degrees, putting the light source on top, the river is going to look totally normal, flowing through the bottom of its valley. Look:

Wait, Is This River Floating?

[Scott Kelly/NASA]


The Cheapest NBN 50 Plans

It’s the most popular NBN speed in Australia for a reason. Here are the cheapest plans available.

At Gizmodo, we independently select and write about stuff we love and think you'll like too. We have affiliate and advertising partnerships, which means we may collect a share of sales or other compensation from the links on this page. BTW – prices are accurate and items in stock at the time of posting.