June 22, 2015
It may not look like much, but this heavily pixelated GIF image is cause for celebration. It effectively cost a robotic space probe more than nine years of travel and $600 million in manufacturing and operational charges. But then again, that’s not why the image is (and must be) celebrated. That privilege goes to the fact that these are the first colour photographs of our most adored dwarf planet. Say hello to an orangeish Pluto, being orbited by a grayish Charon.
Technically, it’s wrong to say Charon orbits Pluto – the two bodies were recently observed by the probe, New Horizons, to be orbiting a point in space called the barycenter. The barycenter is always closer to the larger body, so Pluto’s orbital radius is much smaller than Charon’s (as the GIF below shows).
As New Horizons gets closer to Pluto, its images will become sharper, affording humankind its first glimpse of the dwarf planet as it actually looks – not as imaginative illustrators have depicted it over the years. Alex Parker, a planetary astronomer at the Southwest Research Institute, Texas, had computed a “histogram of hues” in April 2015 showing that most people who didn’t use the correct reddish hue when depicting Pluto went for blueish hues.
On July 14, 2015, we’ll have the sharpest images to date of Pluto and Charon as New Horizons will make the first of its planned flybys, the manoeuvres it was built for, as it will study the atmosphere and surface characteristics of the bodies (here’s why it matters). The image resolution then will be down to a few kilometers. Astronomers can’t wait. On June 16, the National Space Society put out an anthemic video about the New Horizons mission, calling Pluto and its moons “the farthest worlds to be explored by humankind”.