Space ≠ Black
Updated: Jul 25, 2022
It’s very likely that when you think of space, your mind conjures up an image of a large empty black… well, space. Don’t worry, most of us do. It’s what we are used to seeing in our science books and the night sky. But truth is, space is filled with light and color… just not the way we are used to.
Light is everywhere in space. At least, that’s what NASA’s New Horizon discovered. The NASA mission, which passed Pluto about seven years ago, is now beyond 50AU exploring the Kuiper Belt. As part of it’s study, New Horizon subtracted all known light (for example: Milky Way, Sun, galaxies) and, instead of being left with complete darkness, it found unexplained light everywhere. Now, you must be asking, if this is true then why do we see black in space? Well, scientists have asked themselves this question too and, unfortunately, haven’t found a definitive answer. This phenomenon is called Olber’s Paradox.
When talking about color in space, it’s important to make the distinction between natural color and false color. Natural color, like its name suggests, is the color objects have naturally. Fake color is the result of color filtering black and white pictures.
Most of the pictures we see published by NASA or other space organizations are fake color. The main reason why scientists filter their photos is to make objects visible. Most objects in space have too much light for our eyes to process or they fall beyond the visible spectrum of light (i.e. ultraviolet, infrared). Telescopes pick up these objects and make them visible to us, but not always fully. Scientists then add color to highlight certain elements and make them easier for study or simply to make the object detectable. An example of this is the Hubble Telescope, which often provides the world with some of the most beautiful pictures of space. The Hubble Telescope is equipped with high-tech cameras, yet none of these take colored pictures. The sharpness and the number of pixels is what decides a picture’s quality because it determines how much can be learned from it. The Hubble pictures are then processed through three filters: red, green and blue light. Together they form the visible light spectrum and, as a result, we are left with breathtaking out-of-this-world pictures.
What about natural color? Not all objects need to be colored, and some only need to be partially colored. The most common natural colors in space are red and blue. Therefore, while we may not have dazzling magenta and purple nebulas, space is sprinkled with red and blue that our eyes would be able to see naturally.
And yet… there’s more color to be seen.
Planets come in an array of colors, depending on the most common element on its surface. Our friendly neighbor Mars is a great example with its orange red hues. The Mars Reconnaissance Orbiter has been in Mars since 2005 in its mission to search for evidence that water existed in Mars. It is equipped with the largest cameras on a planetary mission plus an imaging spectrometer. Of course, it’s not the only mission taking pictures of Mars. The Mars Odyssey, Mars Exploration Rover Spirit, Mars Global Surveyor, among others, all provide different and vibrant pictures of Mars. To celebrate the colorful array of Mars in its various forms NASA has the Mars as Art showcase, where anyone can see and download the images of our red neighbor.
Mars is not the only planet in space that offers us color. Planets out there vary in color as they vary in size and density. There are some dark planets like TrES-2b0, blue ones like our Neptune or GJ1214, and multicolored ones like Kepler438b.
And then there’s our Earth.
The most colorful marble of those in our sight, filled with color, both at the surface and everywhere under our atmosphere. While we may think of space as “out there”, we often forget Earth is a part of space. Our beautiful color in the deceptively dark universe.
Definitions
AU – astronomical unit is a unit of length roughly the distance from Earth to the Sun.
Olber’s Paradox – if the universe is endless and uniformly populated with luminous stars, then every line of sight must end in a star (light), yet the universe looks black.
Spectrometer – a scientific instrument used to separate and measure components of a physical phenomenon.
Sources:
NASA
NPR.org
Space.com