The New Horizons spacecraft is now just a few days from reaching Pluto. After traveling for 9 years, it is already sending back amazing close-ups.
It will zoom past that tiny Dwarf Planet on Tuesday morning, July 14, with its closest approach a mere one Earth width above the freezing surface. But it will be so frantically busy taking pictures, it won't get around to sending us the best close-ups until a day later—Wednesday.
photo credit: Artist’s concept of NASA’s New Horizons spacecraft as it passes Pluto and Pluto’s largest moon, Charon, in July 2015. (Credit: NASA/JHU APL/SwRI/Steve Gribben)
What do you need to know about Pluto?
- It's tiny: only 1400 miles wide – much smaller than our moon.
- Pluto is really a double object. Pluto and Charon, with a mere two-to-one size difference.
- Make sure you pronounce its moon Karen, like the feminine name. The pair orbit around an empty piece of space between them once a week. Several other even smaller moons are there too, with weird names like Nyx.
- Pluto takes a quarter of a millennium to orbit the Sun. During its slow “year,” its orbit is so tilted that it can appear in odd places in the sky. For example, starting in 2060, it will spend more than a half century in the constellation of Cetus the Whale. So don't be surprised if at astrology gatherings someone says odd things like, “My Pluto's in Cetus.”
On Tuesday morning (the 14th), the New Horizons craft cannot stop and orbit Pluto. Instead it will skim closely by, traveling at 8 miles per second, giving its cameras just a half-hour window of close approach before it continues onward, never to return.
On Pluto's hemisphere that won't be facing those close-up cameras, the approach pictures already show a bizarre series of four giant evenly-spaced circular black spots, each a few hundred miles wide. They resemble nothing else in the known universe.
New color images from NASA’s New Horizons spacecraft show two very different faces of the mysterious dwarf planet, one with a series of intriguing spots along the equator that are evenly spaced. (Credit: NASA/New Horizons/LORRI/Ralph)
So, fortunately, unlike the smudgy, blurry lack of details that Voyager 2 showed on Neptune in 1989, or the blank aqua overcast seen on Uranus in 1986, here finally is an outer planet where our fly-by has lots of detail to observe.
As for whether it's really a planet—let's get into that next week. Meantime, like Mickey, we can all finally say, “Hello Pluto.”