Our eyes are outstanding organs. Tens of millions of receptors known as rods and cones line our retinas, changing gentle into indicators that our brains use to see the world round us. The colours we understand vary amongst particular person people, together with individuals who have color vision deficiency. Fairly actually, we don’t all the time see eye-to-eye with each other.
Simply as colour is subjective amongst people, so too are the colours within the beautiful photos our robotic spacecraft ship again to Earth. Cameras on our area probes act as proxies for our personal eyes, however what they see isn’t essentially what our eyes would see.
“Many of the cameras that we’ve got on our spacecraft and area telescopes do not take colour footage,” stated Heidi Hammel, vp for science on the Affiliation of Universities for Analysis in Astronomy, and vp of The Planetary Society’s board of administrators. “They take black and white footage which might be tuned to particular wavelengths of sunshine.”
Tuning area cameras to particular wavelengths of sunshine helps scientists reply necessary questions in regards to the objects they research, reminiscent of what minerals are on the floor of an asteroid, or what elements are in a nebula. As a result of every area mission has its personal distinctive science inquiries to reply, totally different spacecraft are outfitted with cameras tuned to totally different wavelengths.
Human eyes can typically see gentle with wavelengths between 380 and 700 nanometers. This covers everything of our visible rainbow, from purple at 380 nanometers to pink 700 nanometers.
Many area cameras use filters to seize photos in slim slices of our visible vary. The Cassini spacecraft’s Large Angle Digital camera, as an example, had filters that centered on 460 nanometers (blue gentle), 567 nanometers (inexperienced gentle), and 648 nanometers (pink gentle). By combining photos from all three filters, picture processors may create approximate true-color photos of Saturn and its moons that have been shut, however not precisely equivalent to how our eyes would see them.
“It is a mixture of just a little little bit of artwork and science, however you’ll be able to’t simply belief an image that you just see and suppose that is how it might look to your eyes,” Hammel stated.
We will’t say for sure what the worlds of our Photo voltaic System seem like to us till we see them with our personal eyes from an orbiting spaceship, however we are able to dispel some customary myths. Right here’s a tour of the planets that examines what we learn about every world’s true colours.
What colour is Mercury?
Mercury has a grey, barely brownish look, considerably just like Earth’s Moon. Our greatest world footage of the planet have been made utilizing photos partially comprised of sunshine from exterior our visible vary.
This picture of Mercury comes from knowledge captured by NASA’s MESSENGER spacecraft in 2008:
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