OK, I quote from Joe: "The cheese is old!" Fine, I know it, but I think this is worth mentioning, even now, although it is an old issue.
Let me ask the question: How many planets are there in the Solar System? Do you need some time to think about it? OK, I'll give you ten seconds. Done? Did you just say nine?
Fair enough, nine planets. How do we know that? Well, there's Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. That's magnificent! But wait! It's time to scratch one out of the list. So which one? Earth? Jupiter? The beautiful Saturn? The Sun? No! It's Pluto.
So now, Pluto is not considered as a planet anymore, and we end up having only eight planets in the Solar System. The most baffling question is perhaps, "WHY? I was taught by my teachers and books that there are NINE planets altogether! How can there be eight now? It hasn't exploded, has it?" Of course it's still there, still rotating on its axis and revolving around the sun.
So, why is it now not a planet? What made International Astronomical Union officially declare that Pluto is now just a "rock" (no, they didn't name it a rock)? And now that it isn't a planet anymore, what is it officially known as?
A dwarf planet.
Want to laugh? Go ahead.
Though it might all sound absurd, yet there is some truth in saying that Pluto isn't really a planet. Here is what had happened.
The International Astronomical Union had a meeting in Prague, Czech Republic where they finally agreed on the specific definition of a planet, which called for Pluto being stripped off of its planetary status. It is the same definition which NASA has also agreed upon.
So, what exactly is a planet? Well, the International Astronomical Union now defines planet using three traits:
- It must orbit the sun (duh!).
- It must be massive enough that its own gravity is able to pull it into a nearly round shape.
- It must be dominant enough to clear away objects in its neighbourhood.
So, what would categorise certain celestial bodies as dwarf planets? Simple. A dwarf planet is defined only by Traits 1 and 2. But moons don't count as dwarf planet, though they do orbit the sun, too; they also orbit the planets.
Some of us, if not all, would have known about the most recent discovery of another space body which is even farther away from Pluto, called 2003 UB313 (nicknamed Xena). It is bigger than Pluto, and this is the reason to why the International Astronomical Union decided to finalise about what constitutes a planet.
Even before Xena was discovered, there had been debates in 1930 when Pluto was first discovered by Clyde Tombaugh. They couldn't tell if it was really a planet because of its sheer small size, its distance and also its odd orbit. Many hesitated to decide whether it was a planet or just ice.
Now that the International Astronomical Union has sealed the fate of Pluto, we shall now abide by the eight-planet rule. However, not many countries are really accepting this new rule. If I am not mistaken, Cambodian astronomers are still keeping the nine-planet rule which includes Pluto as a planet.
Now that it is officially an eight-planet Solar System, have our textbooks made the correction?
8 mad rant(s):
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I think i heard about it last year on the newspaper. Hmm..
So is the younger generation kids in school's syllabus change yet?
That's the multi-million dollar question Melanie. Let's ask one of the Form 3's. :)
Haha, Form 3?! That seems to be a long time ago, though it's only less than 3 years back.
Pluto isn't a planet now, eh? I shall keep that in mind. 8 planets, 8 planets, 8 planets....
NOT NINE!
Unless Xena is counted as a planet, haha!
xena... reminds me of tt show tt used 2 crack me up... "xena the warrior" princess. they used 2 show it on s'pore channels. lol, juz being lame at d moment
Form 3? We learnt that in form 3?!
Gosh! That shows how old i really am now.
[thwen]: Although Mike Brown, who discovered Xena, would LOVE to have it named as a planet, the IAU didn't recognise it as so. Too bad for Brown!
[joe]: Yeah, I remember "Xena The Warrior Princess" too. Not very impressed with the show, though, so I've no clear memory of it, except for Xena...
[melanie]: Well, some of us might have learnt that before Form 3 but the syllabus was in Form 3. :)
I thought the Americans still regard Pluto as a planet. The refuse to recognise the change apparently out of arrogance.
Don't get it the wrong way but the current US administration is just downright arrogant. They even are acting in contempt of their constitution! Try searching about habeas corpus on Digg.com if you don't believe me.
[Comrade Cripple]: So much for being a liberal country which is open to change then. But if NASA is OK with it, why wouldn't the country?