by Sarah Davidson
Here’s an interesting case of the intersection of science and art: the false colouring of Hubble telescope images. The Hubble images we see in print, those sublime swirls of psychedelic colour, are actually composites. Hubble creates pictures of the cosmos by recording different wavelengths, most of which are invisible to the human eye, so to us the result is black and white. The wavelengths are then assigned colours and layered to create the spectacular composites that make it into print. The Hubble website even explains the Photoshop process for creating the colour-filled cosmos:
This act of colouring is sometimes more art than science. The NASA website explains that one aim is “to depict how an object might look to us if our eyes were as powerful as Hubble”, but is that relevant? Does this raise questions about the legitimacy of the representations? Is it misleading to print them without a disclaimer?
Space.com published an interesting piece on the ethics of colour and astronomy after it was widely reported that the universe was green and then later beige (or “Cosmic Latte”). They quoted Kenneth Brecher, a professor of astronomy at Boston University, who pointed out that while, from earth, the moon looks white or yellow, moon dust up close appears very dark. “The color of the Moon and the light coming from it are two very different things.”
They also cited a famous example: “In some cases, the colors are as true to reality as anyone could imagine. Other times, as with the Eagle Nebula, colors are changed for effect. Hydrogen and sulfur were each detected in red tones but the hydrogen, which has a shorter wavelength, was made green.”
The Eagle Nebula:
The colour choices become even more questionable when the data falls completely outside the realm of perceivable colour, as with images made using NICMOS, Hubble’s infrared camera. “To these photos, the image specialists typically apply a corresponding range of colors from the visible realm in a logical pattern—red for longer wavelengths and blue for shorter.”
All this is to say—make up your own mind about the ethics of astronomical imag(in)ing, and wonder whether the “skeleton crews” operating NASA’s spacecraft right now will crash any of them.
All Photos from The Hubble website