What Happened to the Former Planet - Pluto?

in #science6 years ago

Growing up, we were taught that there are nine planets in the Solar System, we were made to memorize all of them from Venus, all the way to Pluto which came after Neptune. But as I got older, although I didn’t know what it meant at the time, there were conversations about the nature of Pluto, as scientist started to question the very nature of Pluto. Conversations questioning if Pluto is qualified to be called a planet, this conversations started in the late 1990s. And ultimately, after 70 years of being called and known as a planet, in 2006, the International Astronomical Union controversially decided to reclassify Pluto as a Dwarf planet. This decision reduced the number of planets in the Solar System from nine to eight.

So you may ask, what really happened to Pluto that led to it being relegated from the league of planets to the lower league of dwarf planets? Does this now largest dwarf planet do something wrong? And what exactly happened to it, and can its status change in the future, and can Pluto be called a planet once again later in the future? We will be exploring these in today’s post.

In order to understand why Pluto was relegated from being a planet to being a dwarf planet, first, we need to understand what a planet is, and what qualifies an object to be called a planet.

According to the IAU (International Astronomical Union) in order for an object in the Solar System to be qualified to be called a full-sized planet, it must meet certain criteria. These criteria include

  • It is compulsory that the object should be able to orbit around the Sun

  • The mass of the object must be enough for it be rounded by its gravitational force. I.e, the gravity of the object should be strong enough to pull the object towards itself that results in the object forming a spherical shape

  • The neighbourhood or region around its orbit must be cleared

Pluto meets all two of these criteria, except for the third one, which is having its neighbourhood around its orbit cleared. One of the first criteria, Pluto meets in many respect, it was once the ninth planet away from the Sun. It has an interesting twist to how it orbits the Sun which is quite different from how other planets orbit the Sun. First, Pluto’s orbit is inclined by 17o when compared to the other planets in the Solar System. Secondly, Pluto’s orbit intersects with Neptune's orbit, as a matter of fact, between the year 1979 to 1999, this dwarf planet was closer to the Sun than Neptune was. But for the purpose of this topic, Pluto meets IAU’s first criteria for an object to be considered a planet, which is orbit around the Sun.

It also meets the criteria of having enough gravitational pull that can bring it to a round shape, although, it is not a perfect sphere, it meets this criterion at the very least; frankly, no planet is perfectly spherical. But on the final criteria of being able to clear its neighbourhood around its orbit, that’s where Pluto has a problem. The reason why this criterion is important in determining why an object should be considered a planet or not is that; during the formation of a planet, they become the dominant entity in the environment around the orbit of the Sun. And over time, as the planet further develops, any other object that is found around the same orbit of this new planet is either ejected out of the planet’s orbit, of fuses with the planet and becomes a part of this new planet. To further buttress this, Earth is about 1.7 million times the mass of any other body found within its orbit. In the case of Pluto, the story is completely different, as Pluto is one of the 70,000 objects around its orbit around the Sun, and they are found in the Kieber belt, and more sadly, Pluto accounts for barely 1% of the total mass of the debris of these bodies found in its orbit around the Sun.

And on that note, Pluto had to be reclassified as a dwarf planet as well as Haumea, Makemake, Eris as well as Ceres, since they meet the first two IAU criteria in order to be considered a planet. But none of them can be called a planet simply because their neighbourhood around the orbit around the Sun hasn’t been cleared due to the presence of an individual celestial body.

As defined by the IAU, a dwarf planet is a celestial object that orbits the Sun directly and has enough mass to enable its gravitational pull force its weight towards its core, resulting in the object having a round shape. But since this false ninth planet has failed to clear the region around its orbit of other objects with considerable mass. And this is exactly what Pluto is, around an object that orbits the Sun, but isn’t the most massive object in its neighbourhood, which will result to other objects to be found around its orbit region. And for this reason, it sizes to be called a planet, but rather a Dwarf planet instead, alongside with the other objects found to orbit around its neighbourhood.

Despite Pluto reclassification as a dwarf planet, it hasn’t been entirely forgotten. The New Horizons spacecraft which is part of NASA’s New Frontiers Program was launched in 2006. Its primary mission is to flyby and study Pluto and its systems, and a secondary objective is also to flyby and study other Kuiper belt celestial bodies. And on 14th of July 2015, the New Horizons performed a flyby over the surface of Pluto, which was a bit of a historical moment as the first spacecraft exploring the dwarf planet, hereby giving humanity its first glimpse of this distant world. The New Horizons will continue to explore other regions of the Kuiper belt, helping us understand this unexplored part of our vast Solar System.

Even though it is no longer considered to be a planet, this Dwarf planet has unlocked a new phase of our understanding of the Solar System. There have been conversations of a ninth planet in our Solar System, a real planet that is 10 times more massive than our home planet Earth. This so-called ninth planet is 5,000 times more massive than Pluto, the former ninth planet. I hope to write on this in my next post. The death and reincarnation of the Solar System’s Ninth Planet.

References


Universe Today

Space.com

Loc.gov

Wikipedia

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Lol what a clash of ideas. I read up this in different articles and journals and was planning to write on it in the near future. But here you are with the same thing.

I wanna point out that the downgrading of pluto is still a subject of debate among scientists as some gave instances of some other planets that fail to clear their environs of other bodies. But yet, we still have to go with they position of the body saddled with the responsibility of classifying Celestial bodies, at least for as long as this has not been reversed.

You really captured the details. I may still write on this.

All the best.

@eurogee

the downgrading of Pluto is still a subject of debate among scientists

From what I gather, the conversation is definitive as members of the IAU listed criteria that define the very nature of a planet, criteria that Pluto didn't meet.

scientists gave instances of some other planets that fail to clear their environs

It will be nice to have some examples because, from my research, the neighbourhood of a given planet must not be completely free from debris around its orbit region, but the planet must be the most massive object within that region. In the case of Pluto, there are several other sizeable objects around it, and like I mentioned in my post, Pluto only accounts for only 1% of the mass of the debris found in its neighbourhood.

One of the possible ways a conversation of reclassifying Pluto as a planet can ensue is if Pluto mysteriously starts generating an enormous amount of gravitational energy that is strong enough to pull the other celestial bodies around its orbit path towards Pluto, and being fusing with this other dwarf planets; hence clearing its neighbourhood and start increasing in mass.

Thanks for the feedback.

Too bad, pluto didn't even complete one revolution round the sun from the time it was discovered to the time it was disqualified as a planet. Poor pluto.. I'm sure Pluto would be as sad as my friend's ex :D

I know there are possible contenders to fit into Pluto's replacement.

Nice piece baba

You are absolutely right, wow, you know I never thought of it this way. A lot can happen in a year indeed.

Thanks for contribution bro, it made the post more valuable.

The planet was demoted :)

Yeah, sadly but deservedly.



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