Thanks to Brilliant for  supporting this SciShow video.

Brilliant is offering all SciShow  viewers a 30 day free trial and 20% off an annual premium  subscription for the first 200 people who sign up at Brilliant.org/SciShow. Thanks to a combination of classroom posters, placemats, and NASA press releases, we’ve spent pretty much our whole lives getting the same iconic images of our solar  system burned into our brains.

And when it comes to the planets,  those images are vibrant. Neptune puts sapphires to shame. Venus has a crackling yellow  streak running across it.

And they don’t call Mars the  “red planet” for nothing. Well, it turns out, your childhood  placemat was lying to you. And not just because it called Pluto a planet.

The solar system is way more beige  than you think. But don’t worry: Astronomers have a reason for  collecting all those deceptive images. [♪ INTRO] Color perception is weird. You and I can look at the exact same object and even use the same word  to describe what color it is, but still not see the exact same thing.

Maybe it’s because one of us is color blind. Maybe it’s just because our brains process the information a little differently. But even then, if we both grew up looking at, say, this version of Pluto, and then hopped in a fancy SciFi spaceship to actually visit  it, we’d still be able to agree that our expectations did not match reality.

We learn pretty early on in  life that light comes in a whole rainbow of colors, and  eventually that an object’s color depends on its relationship with that rainbow: Which wavelengths of light does it emit, which does it absorb, and which does it reflect? And since all words are made up, we’ve collectively decided that  longer wavelengths look more ‘red’, and shorter wavelengths look more ‘blue’. But the actual process we have to  go through for our eyes and brains to interpret an incoming light wave  as a given color is complicated, and it’s as much biology as it is physics.

See, there’s a family of cells  in your eyes called cone cells, which for humans come in three specific flavors. For non-colorblind people,  each type of cone cell is tuned to pick up light in one of  three small wavelength bands. You may have heard that each  flavor of cone cell is responsible for detecting either red, green, or blue light.

But really, those wavelength bands overlap. The so-called “red” cones can actually see lots of what we call greenish  colors, too. And vice versa.

So our brains ultimately  determine color based on how much of each flavor of cone are  activated by the light hitting them. But because our bodies are  doing all this hard work to turn light into a perceived  color, it can be hard to figure out what you’d see on that spaceship tour of Saturn. For one thing, it depends a  lot on lighting conditions.

On top of this whole cones  thing, humans have a whole extra special light-detecting process that  activates in low-light situations. And those low light cells aren’t  great at picking up colors themselves, but they help your cones  detect those “cyany” shades. So if you’re farther away from  the Sun, the colors of the planet you’re admiring could be totally distorted.

But even assuming well-lit conditions, an image you grew up with may not match reality for a few different reasons. First, I’ve gone this far without acknowledging that not all light is visible to the human eye. That Roy G.

Biv range is just a small sliver of wavelengths sitting in the middle of  the full electromagnetic spectrum. But while we can’t see infrared  radiation, or ultraviolet rays, and so on, it’s all still interacting with  bodies in the solar system. So scientists make machines that  can detect this invisible light, stick them onto telescopes,  and fling them into deep space.

And if you’ve got a probe that  detects, say, infrared light, you’re free to use any visible  color you like to display that data. These are called False Color images, and they’re vitally important to astronomy. Take Venus, for example.

It’s famously covered with  a thick layer of clouds. And you might think that during your space ship’s tour of the solar system,  you’d look out your window and see a bunch of pretty shapes  swirling around that atmosphere. But no.

You’d likely just see  a featureless, off-white ball, and the child sitting next to  you on this three hour tour would be moaning “BOOOOOOOOOOOORRRRRING” . But it’s not like astronomers  are trying to catfish us. They’re just relying on non-visible wavelengths to study what those clouds are doing.

And for those of you used to  seeing images that look like this, well that’s thanks to a  probe scientists used to see through all that mess of an atmosphere. But they had to use radio waves to do it. And when they chose to add  some color, they picked hues that were based on a few snapshots  taken by two previous landers.

Meanwhile, images that  exclusively use visible light may not be ‘naturalistic’, either. For one thing, they might ramp up the contrast and saturation to get a better view of  certain planetary features. But even images that claim to be true color… the ones that try to look as close as possible to what the human eye will see…are lying to you.

At least a little bit. Because digital cameras do not capture light the exact same way that eyeballs do. I know!

Mind blown! No picture you've ever seen has been a perfect representation of reality! Now, space probes can have cameras that work a bit like human cone-based color vision, in that they have detectors that each capture a different range of light wavelengths.

But more commonly, they have filters they put over their cameras to pick up one color at a time. Because of this, making a color  image is less like human sight, and more like taking three black-and-white images, assigning each one a different color, and then smushing them all together. And on top of that, the wavelengths  all these cameras pick up aren’t quite the same as the  ones the cones in our eyes do.

For example, the Hubble camera  that took this image of Mars used filters that peak at 410 nanometers, 502 nanometers, and 631 nanometers. Meanwhile, human cone cells are most sensitive at 420, 530, and 560 nanometers. So it’s close, but it still  isn’t quite what Mars-bound astronauts will witness upon final approach.

You will at least notice,  however, that Mars is very much not living up to its nickname the “red planet”. But sometimes, a probe’s filters don’t  even try to mimic our cone cells. Voyager 1 took photos of Jupiter  using cameras attuned to the violet, blue, green, and orange parts  of the electromagnetic spectrum.

That’s because those particular filters let scientists study gas giant atmospheres better. Or more specifically, the different kinds of gasses in those atmospheres. For example, the orange filter was meant to hone in on any signs of methane.

But this science goal meant that,  in order to make true-color images, scientists had to be even more  careful when translating the data into something that would  mimic what our eyes would see. And just like with translating  languages, there’s a certain art to it. Different people can  interpret the task differently without a clear-cut right-or-wrong answer.

Put this all together, and it’s  no wonder why different probes can observe the same planet and produce true color images that don’t match. Is this Hubble image of Saturn less  accurate than this Cassini image? The answer isn’t no, but it isn’t yes, either.

But sometimes, you really do need to go back and reprocess your data to  get a more accurate picture. Which brings us to a new analysis  of the raw Voyager 2 data that produced iconic images  of Neptune like this one. Images that are so brilliant  they swayed some children into picking Neptune as their favorite planet.

Images that have been in our  collective heads for decades. But in 2024, a team of astronomers  reprocessed the colors, and came up with what might be described as a bit of a disappointment to  all those former children. Turns out Neptune is actually a lot closer to Uranus in color: a faint, light blue.

And its iconic deep blue hue was  the result of over-saturation. This isn’t a huge shock to  the astronomers that have been studying Neptune all this  time, but it sure is to me. And probably to you.

It’s yet another planet that  wouldn’t look as dramatic to the human eye as we grew up thinking. But hey, it’s not like you or I will ever get the chance to see Neptune up close. And it’s nice to know that astronomers can go back to old data and learn new things.

Plus, there’s one planet which looks  as vibrant as you think it does. You’re standing on it! Which just like Neptune, makes  me feel a little less blue.

When some of us are feeling blue, we  turn to music to lift our spirits. And music sites these days are really good at figuring out what song we’re  in the mood to listen to next. They’re able to make such accurate predictions because of their giant data sets.

And now you can use real data from Spotify to gain skills in predicting with probability. All you have to do is  complete the case study called Topping the Charts with Spotify, now  available at Brilliant.org/SciShow. This case study is one of  several offered by Brilliant, the interactive online learning  platform with thousands of lessons in science, computer science, and math.

They also offer case studies  on electric vehicle value, rental property value, and going  viral on social media platforms. It’s an engaging way to play with data. And while you’re doing that,  you’ll learn about Bayes’ Theorem, Cumulative Distribution Functions,  and laws of probability.

To get started, go to Brilliant.org/SciShow or the link in the description down below. That link also gives the  first 200 people who sign up 20% off an annual premium Brilliant subscription. And you’ll get your first 30 days for free!

Thanks to Brilliant for  supporting this SciShow video! [♪ OUTRO]