Who would have thought that Clyde Tombaugh’s discovery of the long sought trans-Neptunian planet in February of 1930 would have us flying by that feeble speck 85 years later! What were two separate, minute points on Clyde’s January 1930 discovery plates are now resolved with unprecedented clarity and detail to be an ice world of unique and sublime beauty, wondrous and fascinating, ethereal and unequaled in the solar system!
One week ago, NASA released new images acquired form New Horizon’s closest approach to Pluto on 14 July of this year. Obtained by the LORRI imager from a distance of 12,500 Km, they are likely to be the highest resolution images we’ll see of the icy world’s surface! With a staggering resolution of 80 meters per pixel, the resolution was only 2x the theoretical resolution possible with the 20cm (8″) Ritchey-Chrétien telescope, the heart of LORRI. The quality of the images, the sharpness and depth of the detail is a testament to the optical quality of the instrument, the spacecraft’s stability, guidance and precision engineering. And now, today, the space agency has released the same images but now in color! This 80 km wide swath features a section of the frozen nitrogen plain of Sputnik Planum with 2.4 Km high water-ice mountains forming the northern shoreline of Tombaugh Regio, the now famous “Heart of Pluto”. To get a sense of scale, the highest of these mountains are about 1/3 the height of Mount Everest or about 1/10 the height of Mars’ Olympus Mons. That the nominal temperature on Pluto’s surface never goes above a frosty 65 Kelvin (65 degrees above absolute zero) guarantees that nitrogen will always be in a frozen state and that the water-ice mountains will have a hardness consistent with that of solid rock.
If we were onboard the spacecraft, this would be one view that we might see of many to come, the best thus far. Over the next 11 months, the remaining flyby data stored in the spacecraft’s two low-power solid-state recorders (one backup) will be downloaded via a 1 kbps comm downlink between the spacecraft’s 2.1 meter high-gain antenna and NASA’s Deep Space Network (DSN). The two solid-state recorders, with a combined capacity of 16 GB (8 GB each), are much like the solid-state flash memory found in modern digital cameras or mobile phones.
At a distance now of 35 AU from earth (round-trip light travel time of 9+ hours), the intrepid spacecraft is racing out of the solar system at a velocity of 50,400 Km/hr (35 Km/sec) towards the heretofore uncharted territory of the Kuiper belt. As of November 8th, the spacecraft successfully performed the last in a series of four targeting “burns” that put it on course for a rendezvous with 2014 MU69. Otherwise known as a KBO (Kuiper Belt Object), this ancient body is more than 1.5 billion Km beyond Pluto or about the distance to Saturn from the Earth. If an extended mission is approved, New Horizons will fly by and explore this remote, frozen world in January of 2019.
At Pluto’s distance, an onboard observer would see the sun 1,600 times fainter than the noon-day sun on earth. To get a sense of how that would look, imagine the solar disk 40 times smaller than it is now, or 1/80 of a degree wide, with a sky brightness comparable to twilight about 30 minutes after sunset; thus, it is always “Pluto Time” somewhere on earth. The solar disk would appear 40 times smaller than it does from earth and 250x brighter than the full moon. Adding another 1.5 billion kilometers for the distance to 2014-MU69, the sun would be 50 times smaller (1/100 of a degree wide), 2,500 times fainter than it appears from Earth and and 100x brighter than the full moon.
In a very real sense, we are “going where no one has gone before”, explorers of a new frontier just as the European explorers sailed the treacherous seas in search of the New World 500 years ago.
Along with live telemetry (position, speed and direction) of the spacecraft, the most recent downlinked images (both raw and processed) are available at the New Horizons home page of the Johns Hopkins University Applied Physics lab.
Imagination is more important than knowledge
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