Emma is one of my regular guest bloggers. I feel really thrilled about the possibility to post one educating post of this great blogger once a month over the next couple of months. Thank you so much, Emma, for sharing these great posts with us! If you would like to check out the previous guest posts, this amazing blogger wrote for me, head over here.
Though many Pluto fans would beg to differ, Pluto is no longer a planet. It has been classified as a dwarf planet in the farthest reaches of our solar system. It is one of a group of similarly icy worlds called Kuiper Belt objects, from where comets are thought to originate. Neptune, Uranus, Saturn, and Jupiter are also thought to have captured their rings and moons from this belt of objects. The Kuiper Belt is analogous to an asteroid belt, but it’s not full of asteroids. Its objects are more like dirty snowballs, like a snowball compacted together from such a thin layer of ground snow that some dirt gets mixed in as well. On Earth, you might end up with twigs and leaves in your snowball. In the Kuiper Belt, you’re more likely to find stone and iron. You better not get caught in a snowball fight out there!
After Neptune was found, scientists were convinced a Planet X existed beyond it. Calculations suggested such a body disturbed Neptune’s orbit. It would have to be of large mass—possibly a planet between the sizes of Earth and Neptune. But calculations didn’t make clear where this planet should be found. One astronomer managed to find Planet X and dubbed it Pluto, and almost immediately, up sprang controversy. Pluto was tiny, even tinier than Mercury. How could it possibly be Planet X? But then, why did it exist? Were the calculations wrong?
Years later, another astronomer was searching for objects near Pluto when his instruments picked up a tenth planet. This planet, by the definition of “planet” that was accepted at the time, was larger than Pluto. Therefore, it was definitely a planet. But it, like Pluto, was smaller than Mercury. And the tenth planet wasn’t the last tiny planet to be found. In subsequent years, many more objects orbiting near Pluto were located, and the truth became unavoidable. Planet X did not exist, at least not as a whole planet. There was indeed a measure of mass in the solar system beyond Neptune, large enough to disturb Neptune’s orbit and yield the calculations that had inspired the search in the first place. “Planet X” was a belt of icy objects of which Pluto, the tenth planet, and many others were a part, and it came to be called the Kuiper Belt. And thus, found to be orbiting with a cloud of objects just as an asteroid would, Pluto lost its status as a planet.
Since then, Pluto has not been a subject of interest. Astronomers have focused their attention on mysteries beyond the solar system, on black holes, on galactic collisions, on the acceleration of the expansion of the universe, on planetary formation, on nebular contraction, and much, much more. But Pluto is more relevant than it seems. In casting Pluto aside, we have committed the scientific crime of accepting ignorance, of relegating an object of the cosmos to an object not even worth our attention. The New Horizons launch means to correct that.
NASA shelved or canceled four different concepts of Pluto missions before finally bending down to study New Horizons, a pioneer of the new era. By then, the team only had four years to get New Horizons built in time for the last Jupiter gravity assist in the 21st century’s first decade and then an 9.5-year flight across our planetary system. New Horizons is the most innovated spacecraft NASA has yet sent out. It has a lightweight design that produced the fastest spacecraft launch ever: 35,800 mph (57,600 hm/h). It crossed the moon’s orbit in just nine hours—almost ten times as quickly as the Apollo missions did. It reached Jupiter in 13 months—five times faster than the Galileo spacecraft and three times faster than the Saturn-bound Cassini probe. With the boost from a Jupiter gravity assist, this speed enables it to reach more distant Pluto several years faster than Voyager reached Neptune. New Horizons may be Pluto’s first launch of its own, but it is already proving an immensely promising one.