Is Pluto a planet?
Pluto is the farthest known planet from the sun; it was the first Kuiper belt object to be discovered. Pluto is reclassified as a dwarf planet in the Kuiper belt, a ring of bodies beyond Neptune.
In this article, you will get to learn all the facts about Pluto, when it was discovered, it moons, distance and also get to find out why Pluto is not a planet and why it is called a dwarf planet.
Facts about Pluto
- Pluto got its name in 1930 from an 11-old schoolgirl, Venetia Burney of Oxford, England.
- In 2006, Pluto was officially reclassified from a planet to a dwarf planet
- A year on Pluto is 248 Earth years. A day on Pluto lasts 153 hours, or about 6 Earth days
- Pluto orbits the Sun about 3,670,050,000 miles (which is 5,906,380,000km away on average, about 40 times as far as Earth, in a region called the Kuiper Belt.
- Pluto has five moons, Charon which is the largest moon, is so big such that Pluto and Charon orbit each other like a double planet.
- Pluto has a diameter of 1,473 miles (2,370 km), this is less than one-fifth the diameter of Earth.
- Pluto orbits the Sun about 3.6 billion miles (5.8 billion km) away on average, about 40 times as far as Earth, in a region called the Kuiper Belt.
- Pluto’s orbit is an ellipse and it is tilted compared to the orbits of the eight planets in the solar system.
- Pluto is very cold, its temperature is -378 to -3960F (-228 to -2380C).
- The atmosphere Pluto is very thin; it constitutes nitrogen, methane ice and carbon monoxide. The atmosphere has a blue tint and distinct layers of haze.
What is Pluto?
Pluto is the farthest planet from the sun, it is the second-most-massive known dwarf planet in theSolar System after Eris, and the ninth-largest and tenth-most-massive known object directly orbiting theSun. Pluto is smaller than the other eight planet and not only that but also smaller than seven of their satellites, including Earths moon.
Is Pluto a Planet?
Starting from 1992 and onward, Astronomers discovered other bodies in space orbiting in the same volume as Pluto, showing that Pluto is part of a population of objects called theKuiper belt, (Kuiper Belt is a large donut of thousands of small, icy objects that orbit the sun beyond Neptune). This made its official status as a planet controversial, with many questioning whether Pluto should be considered together with other planets in the solar system or separately from its surrounding population. Museum and planetarium directors from time to time created controversy by removing Pluto from planetary models of the Solar System.
In February 2000 after the renovation of theHayden Planetarium, it was reopened with a model of only eight planets, which made headlines almost a year later.
As objects increasingly closer in size to Pluto were discovered in the region, it was argued that Pluto should be reclassified as one of the Kuiper belt objects, just asCeres,Pallas,JunoandVestalost their planet status after the discovery of many otherasteroids. On July 29, 2005, astronomers atCaltechannounced the discovery of a newtrans-Neptunian object,Eris, which was substantially more massive than Pluto and the most massive object discovered in the Solar System sinceTritonin 1846. Its discoverers and the press initially called it thetenth planet, although there was no official consensus at the time on whether to call it a planet. Others in the astronomical community considered the discovery the strongest argument for reclassifying Pluto as a minor planet.
Even though Plutoisa small object in the solar system, its size wasn’t the only reason it lost its coveted status as aplanet. Objects in space were expected to possess three criteriabefore they are being considered as planet.
In August 2006, there was an official definition of planet by the International Astronomical Union, which has three criteria stated below:
- The object must be in orbit around the Sun.
- The object must have a sufficient mass to assume hydrostatic equilibrium (a nearly round shape).
- The object must have “cleared the neighbourhood” around its orbit.
Based on International Astronomical Union (IAU) definition of planet, Pluto is not a planet, It is one of the Kuiper Belt objects because it meets only two criteria but failed to meet the third criteria which states that object must have “cleared the neighbourhood” around its orbit. Pluto mass is obviously less than the combined mass of the other objects in its orbit: 0.07 times, in contrast to Earth, which is 1.7 million times the remaining mass in its orbit aside excluding the moon. The IAU finally decided that bodies in space, like Pluto, that meet criteria 1 and 2, but do not meet criterion 3 would be calleddwarf planets. Pluto is a dwarf planet. A dwarf planet is defined by the IAU, as a celestial body in direct orbit of the Sun that is massive enough that its shape is controlled by gravitational forces rather than mechanical forces (and is thus ellipsoid in shape), buthas not cleared its neighboring region of other objects.
However, many other objects exist in space with similar size and mass to Pluto jostling around in its orbit and they are considered as dwarf planets, and except Pluto crashes into many of them and gains mass, it will remain a dwarf planet. Eris, Haumea, Ceres, Makemake are few examples of dwarf planets belt objects (KBOs) system.
Who discovered Pluto?
Pluto was discovered in February 18, 1930 at the Lowell Observatory in Flagstaff, Arizona. This discovery was made by an astronomer,Clyde Tombaugh and was originally listed as theninth planet in orderfrom the Sun. Pluto was officially classified as dwarf planet; this was widely belied to be a demotion to the planet. The question whether Pluto’s planet is a planet or not hasstirred up controversy anddebatein thescientific community, and among thegeneral public.
Pluto was the only planet that was named by an 11-year-old girl, Venetia Burney of Oxford, England in 1930. Venetia Burney was interested inclassical mythology and also in astronomy suggested to her grandfather Falconer Madan, that the new discovery should be named for the Roman god of the underworld, the name was appropriate for such a presumably dark and cold world. Her grandfather then forwarded the name to Lowell Observatory and it was accepted. The name also honors Percival Lowell, whose initials are the first two letters of Pluto.Since then, Pluto is considered as one of the closest large Kuiper Belt object to the Sun.
Pluto has five moons. The largest of all the moons is Charon is almost as big as Pluto itself. Due to its size, they both (Pluto and Charon) orbit each other as if they are two planets. Pluto and Charon are just 12,200 miles (19,640 km) away from each other; this distance is less than the distance by flight between London and Sydney. Pluto has a reddish tint while Charon appears more grayish in colour. Pluto’s moons are named for other mythological figures associated with the underworld (land of the dead). For instance, Charon is named for the river Styx boatman who ferries souls in the underworld (as well as honoring Sharon, the wife of the discoverer- James Christy). Nix is named for the mother of Charon, who is goddess of darkness and night. Hydra is named for the nine-headed serpent that guards the underworld; Kerberos is named after the three-headed dog of Greek mythology (and called Fluffy in the Harry Potter novels) and lastly, Styx is named for the mythological river that separates the world of the living from the realm of the dead.
Pluto orbit is highly elliptical (it is far from being circular), its orbit has a more oval shape compared to the rest of the planets. It can take Pluto more than 49 times as far out from the sun as Earth, its distance from the sun varies because of its elliptical orbit; sometimes the dwarf planet is a lot closer to the Sun than at other times, its orbit brings it closer to the Sun than Neptune planet some other time. Like the planet Uranus, Pluto rotates on its side; its axis tilted about 120 degrees.
As Pluto moves closer to the Sun, ices on its surface gets warm slightly and evaporates to gas and form a thin, mostly nitrogen atmosphere. As it moves away from the Sun, the gases cool and refreeze. The atmosphere may wear away as Pluto moves farther away from the Sun. The last time Pluto moved closer to the sun was from 1979 to 1999, during this periods, Pluto crossed Neptune at its orbit and turn out the farthest planet from the sun (until it was reclassified as a dwarf planet). However, scientist suggest that this wont take place again but until in 2227. It takes 248 Earth years for Pluto to make one revolution around the sun. That means one year on Pluto is about 248 Earth years. Pluto takes 6 1/2 Earth days/nights to rotate, so one day on Pluto is about 6 1/2 days/nights on Earth.
Pluto Distance from the Sun
Pluto is covers a distance of 3,670,050,000 miles (which is 5,906,380,000km), this is about 39.482 times that of Earth. Pluto takes about 247.7 years to go round the sun; Since Pluto is far from the sun it was never visited by a spacecraft , it was only viewed with a radar from afar off not until July 2015, NASAs New Horizons space made a close flyby the planet and took which reveal a varieties of surface features like mountains.
Pluto has a diameter of 1,473 miles (2,370 km); this is less than one-fifth the diameter of Earth, and only about two-thirds as wide as Earth’s moon.
Pluto has a surface temperature of -378 to -3960F (-228 to -2380C). Pluto is the coldest planet in the solar system, it has a thin surface of frozen methane and if possible, some Nitrogen as well, this surface is said to be very cold which is why it cant sustain living things. Most times, when Pluto moves closer to the sun, its surface ices will melt and temporarily form a thin atmosphere, consisting mostly of nitrogen, with some methane. Scientists believe that the planet could contain water ice, methane ice and rocks as well.
Its low gravity, which is a little higher than one-twentieth of Earths, could cause the atmosphere to extend much higher in altitude than Earth’s. When Pluto moves far away from the sun, most of its atmosphere is thought to be frozen wears away but when it is closer, the atmosphere appears to be visible. Pluto can apparently experience strong winds. Theatmosphere also has brightness variations which is best explained by gravity waves, or air flowing over mountains.
NASAs New Horizons space made a close flyby in 2015 and during the flyby, it made a close and detailed observation of the planet and its moons, which reveals that Pluto has some major surface features such as mountains that is as high as 11,000 feet (3,500 meters), compared to the Rocky Mountains on Earth. The images also showed that the surface of Pluto is covered with methane nitrogen ice, carbon monoxide and nitrogen ice, these materials are not strong enough to support such enormous peaks, however, astronomers think that the mountains are formed on bedrock of water ice. NASA images showed that Pluto’s surface is a large heart-shaped region known unofficially asTombaugh Regio(named after Clyde Tombaugh;regiois Latin for region). The left side of the region (an area that takes on the shape of an ice cream cone) is surrounded by carbon monoxide ice. Another striking feature on the surface of Pluto is the methane ice which is seen in abundance,Pluto’s surface is also seen to possess ice ridge terrainwhich looks like a snakeskin, the crust could containcomplex organic molecules. However, Pluto is primarily made of ice and rocky core and a mantle of water ice surrounds it with more exotic ices such as methane, nitrogen.Most times, its orbit crosses the orbit of Neptune and when this happens, Neptune becomes the farthest planet from the sun.