They must also be “determined to succeed”, Nasa explained. The reasoning, as explained in the IAU’s Resolution B6, was that Pluto only had two of what the IAU decided were the three characteristics of a planet – that it is in orbit around the sun, that it has sufficient mass for its self-gravity to overcome rigid body forces and give it a nearly spherical shape, and that it has cleared the neighborhood around its orbit of other objects, meaning that it’s either collided with, captured or driven away smaller objects nearby. ², where E is energy, m is mass and c is the speed of light. To be considered a planet, a celestial object must meet three criteria: It orbits the sun; it has sufficient mass for its self-gravity to overcome rigid body forces and give it a nearly spherical shape; and it has cleared the neighborhood around its orbit of other objects, meaning that it’s either collided with, captured or driven away smaller objects nearby. Because of the size of Pluto’s orbit around the sun, a year on Pluto lasts for the equivalent of 90,530 Earth days, or nearly two-and-a-half centuries on our planet, according to NASA.

Instead, the IAU decided, what had been considered the most distant of the nine planets actually belonged in the new category of dwarf planet, a category that also included Ceres, the largest object in the asteroid belt between Mars and Jupiter. Instead, think of rotation as the spin responsible for night and day. People used to think the planets were a small number of gods ruling in their orbits,” he explains. “Then scientists discovered the solar system is messy, that planets don’t all orbit the sun, and that they kick each other around and share orbits with other objects. It makes sense if you think about it: Those six extra hours each year add up to 24 hours (one whole day) over the course of four years. Every major commercial transport and almost every military jet built in the United States over the last 40 years has been tested in this facility.

While the United States had some issues during the first spacewalk, astronauts go to great lengths to prevent themselves from becoming untethered. The Kennedy Space Center is expected to be spared from the brunt of Hurricane Ivan, the third major storm to hit the eastern United States in a month. From his post on the International Space Station, Reisman even managed to throw out the first pitch on April 16, 2008, to open the Yankees versus Red Sox game (via satellite broadcast, of course). The first stated that the same laws of physics apply equally in all constantly moving frames of reference. This isn’t the same as an orbit. Leap years, or those years with the extra day of Feb. 29, compensate for our underestimating of Earth’s orbit. Thankfully, some bright minds and world leaders learned more about the Earth’s elliptical journey around the sun.C.E., Julius Caesar created the Julian calendar to include leap years. Leap seconds are added to standard atomic clocks to compensate for inconsistencies in the Earth’s rotation on its axis. Over time, however, our ability to measure the Earth’s rotation and orbit became more refined and precise, forcing us to adjust how we tracked time over the centuries, whether it’s with paper-thin calendars or high-tech smartphones.

After a debate among scientists sponsored by the Harvard-Smithsonian Center for Astrophysics in 2014, the majority of the nonexpert audience voted for a simpler definition of planet – basically, that it had to be spherical and orbit around a star or the remnants of one – that included Pluto, according to an article on the center’s website. Pluto flunked the IAU’s last test, because it shares its orbit with thousands of smaller icy objects in the Kuiper Belt, a region that’s between 2.5 and 4.5 billion miles (4.5 and 7.4 billion kilometers) away from the sun. The second said that the speed of light – about 186,000 miles per second (300,000 kilometers per second) – is constant and independent of the observer’s motion or the source of light. And there’s plenty that’s interesting about Pluto, which Metzger described as the second most complex planet after Earth in the solar system. As long as the planet still makes its mathematically messy journey around the sun, we’ll have time to welcome Feb. 29 and calculate the next one. The man who never asked for recognition was eulogized as a true American hero whose “one small step” remains one of the proudest collective moments in human history.