Clyde Tombaugh Just Passed Pluto
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| How New Horizons shot through the Pluto System this past Tuesday morning. Its data gathering stage lasted several hours then it switched into transmission mode and "phoned home." |
In 2006 we shot New Horizons into space. It burned a lot of its fuel speeding up to a record 36,000 miles per hour, carrying the probe away from Earth on a trajectory toward Jupiter. Whereas it took the Apollo mission astronauts three days to get to the Moon, New Horizons made the trek in just nine hours and kept going. In 2007 we used Jupiter's gravitational force to burn a bit more fuel, slingshoting the space probe way out on a trajectory to rendezvous with Pluto, still some 3,000,000,000 miles away from Jupiter which was roughly 480,000,000 miles from Earth. It would take New Horizons another eight years to get to Pluto and when it arrived it would be going extremely fast. In the meantime it mostly hibernated.
We flew like a bullet through the Pluto System, with its moons in various places and phases. Our trajectory brought us inside the orbit of Charon, the largest and first known moon. Incredible video taken of the surface from about 48,000 miles up was released just a few days after New Horizons completed its Pluto flyby. At its closest the space probe was at an altitude of a mere 7,750 miles (that is what the countdown was all about back at the Tuesday morning celebration), but that only lasted a few seconds. At the speed New Horizons was getting it, the probe was over the surface only 3 minutes.
Now imagine that. In 2006 we shot off a probe and sent it roughly 3.5 billion miles over nine years and aimed it to within less than 10,000 miles of the orbiting target. It is an amazing example of our finest humanity. That wondrous achievement of rocketry and physics is broadened by the fact that we sent the ashes of the man who discovered Pluto in the 1930's. It is thus ritualized in our highest esteem. There is no scientific reason for delivery of the ashes far out to the Kuiper Belt - the furthest any human has ever traveled. A feeling about the mission caused that. And that is a cheerful, hopeful thing.
The first image we have of the Earth as seen from space was taken in 1946 while mounted on a V2 rocket Americans were experimenting with after World War Two. In 1964 a probe we launched photographed the Moon for the first time. Mars came in 1965. Venus in in 1973 by Mariner 10, which also shot the first closeup of Mercury in 1974, our first double planet probe.
Voyager 2 captured Jupiter in 1979. Voyager 1 gave us Saturn's first closeup in 1980. Voyager 2 meanwhile went on to show us Uranus in 1986 and a surprisingly beautiful Neptune in 1989. Then another 26 years passed before this moment I am blogging about, the longest time between planetary closeups since that V2 rocket went up in 1946. That historic fact makes this moment even more awe inspiring for me, connected through human time.
New Horizons flew by at its closet distance (7,750 miles) as I was at my desk at work last Tuesday. I always get to work early so I can think and plan and get somewhat of jump on the day. I had my iPad with me and NASA TV up. It was about 7:45 AM. A crowded room of scientists and assorted nerds were counting down. 10...9...8... Louder each time as if it were New Year's Eve in July. I smiled and watched them all shout for joy and hug and shake hands....but there was nothing from New Horizons. It seemed a bit absurd to a coworker and me who were emailing back and forth as the moment happened.
Of course, it was going to take awhile to get the actual "live" photography from the probe. So everyone was ecstatic on sheer faith that we did not unexpectedly misfire and crash into Pluto. Or that the probe would successfully switch to data send mode and successfully realign its antennae back toward Earth. It was a glorious sight unseen. New Horizons was traveling super fast, after a nine year journey. You had one shot at everything and everything was validated about 12 hours later when the first images were released to the public.
It was one amazing view after another. Scientists were immediately impressed with the red tinge of the planet, like Mars. Also surprising was the smoothness of its surface, with its lack of cratering, indicating a geologically alive core. Mountains at least 11,000 feet high were discovered (measured by the length of their shadow from the a perspective of the flyby). This was totally unexpected. My own take is that the massive craters we see on Earth and the Moon and Mars and Mercury were the result of the Sun's gravitational pull on the Solar System's debris, which is comparatively slight out at Pluto's distance. But that is just an amateurish speculation on my part.
After the immediate flyby, New Horizons snapped shots of the entire Pluto System. It fell into the shadow of the dwarf planet at 8:45 AM this past Tuesday. I look forward to seeing how it looks from that perspective, eclipsing the Sun at that great distance. By 10 AM its speeding trajectory briefly fell in the shadow of Charon. The probe continued to gather data until about 4:30 when it used its limited power to switch from data gathering to transmission mode, which it will remain in for most of the the next 16 months. The probe is so far away that it takes about 4 and a half hours to send data to Earth. And it is constantly moving further away.
The easiest way to grasp the distances involved within our Solar System is through Astronomical Units (AUs). The Earth is about 93,000,000 miles from the Sun and that equals 1 AU. Jupiter orbits at a distance of about 5 AU. Pluto has in irregular oval orbit that averages about 39 AU. That's a long way out.
Going to Pluto in just nine years is hauling ass in space within present human limitations. Of course, this is still a small thing, an undetectable thing in the vastness of space itself. But it is nevertheless a magical human moment. We sent Clyde Tombaugh to Pluto and beyond. He now joins Voyager 1 and 2 as well as Pioneer 10 and 11 in the furthest reaches of human touch. Hello out there...
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