what do you think of this idea having 12 planets in or solar system? Is it possible there are more planets?

Answer 1

The way the news has been misreported ("3 new planets have just been discovered"), anyone would think astronomers had only just cottoned on to the existence of Ceres (discovered 1801) Charon (discovered 1978) and Xena (discovered 2003),

Not so, The process currently going on in the IAU's conclave is much more like the beatification of saints. It is one of upgrading the status of what we already know about and there are a whole load more potential candidates for planetary status.

I would like to start by pointing out how we have been here before, first 200 years ago and then 150 years ago. i.e. we have been faced with a crisis of definition and classification of Solar System objects, as their numbers burgeoned, And then come to how burgeoning the numbers currrently are.

The Solar System was thought for two millennia to consist of just 8 objects, the Sun, the Earth, our Moon and the 5 classical planets known from antiquity (Mercury, Venus, Mars, Jupiter, and Saturn). The Copernican heliocentric model of the Solar System reclassified Earth as a 6th planet in the mid-16th Century but did not add to the number of known objects. But in the next 200 years that all began to change ...

On January 7 1610 Galileo discovered the 4 largest Moons of Jupiter (later to be named Io, Callisto, Ganymede and Europa but just called Jupiter I, II, III and IV by GG himself), (1 star, 6 Planets & 5 Moons)

On March 25th 1655 Christian Huygens, a Dutch astronomer discovered a moon orbiting Saturn, which was later named Titan. Huygens was clearly struck by the same thought as our questioner "Okay, we know about four new moons, Are there any more?" And went looking,(1 star, 6 Planets & 6 Moons)

Four more moons of Saturn follow by the end of the 17th century: October 25, 1671 Iapetus and December 23, 1672 Rhea, March 21, 1684 Tethys and Dione, All found by Cassini, (1 star, 6 Planets & 10 Moons)

Then on March 13th 1781 Sir Willliam Herschel discovered Uranus (1 star, 7 Planets & 10 Moons),

Then in rapid succession Herschel disconered 2 moons of Uranus and 2 further moons of Saturn: Oberon (U) January 11, 1787, Titania (U) January 11, 1787, Enceladus (S) August 28, 1789 and Mimas (S) September 17, 1789. (1 star, 7 Planets & 14 Moons), (Earth: 1, Jupiter: 4, Saturn: 7 and Uranus: 2)

There were now 22 objects, 5 of them found by Herschel and 4 apiece by Galileo and Cassini, And within another 20 years the total had risen again to 26 objects with the discovery of the first four asteroids. (They weren't called asteroids till Herschel coined that term, in 1802, shortly after the second of these had been discovered,)

These were 1 Ceres on January 1, 1801, 2 Pallas on March 28, 1802, 3 Juno on September 1, 1804, 4 Vesta on March 29, 1807,

Johann Elert Bode believed Ceres to be the "missing planet" that Johann Daniel Titius had calculated to exist between Mars and Jupiter, at a distance of 419 million km (2.8 AU) from the Sun. Ceres was assigned a planetary symbol, and remained listed as a planet in astronomy books and tables (along with 2 Pallas, 3 Juno and 4 Vesta) for about half a century until further asteroids were discovered.

However, Ceres turned out to be disappointingly small, showing no discernible disc, and so Sir William Herschel coined the term "asteroid" ("star-like") to describe it.

With a mass of 9.5×10^20 kg, Ceres comprises about a third of the estimated total 3.0±0.2×10^21 kg mass of all the asteroids in the solar system (note how all these amount to only about 4% of the mass of the Moon).

So now there were 1 star, 11 Planets & 14 Moons with four of those planets also being termed asteroids as Herschel took the first tentative step towards differentiating minor from major planets,

38 years pass and then in 1845 the asteroid 5 Astraea is discovered and on September 23, 1846 the planet Neptune and a mere 17 days later on October 10, 1846, Neptune's moon, Triton. (1 star, 12 Planets 15 Moons and 1 non-planetary Asteroid)

The pace of discovery then starts to really hot up. Four more asteroids: 6 Hebe on July 1, 1847, 7 Iris on August 13, 1847, 8 Flora on October 18, 1847, and 9 Metis April 25, 1848

Then on September 16, 1848 a sixth moon of Saturn called Hyperion is discovered,

Plus a further 6 asteroids:10 Hygiea on April 12, 1849, 11 Parthenope on May 11, 1850, 12 Victoria on September 13, 1850, 13 Egeria on November 2, 1850, 14 Irene on May 19, 1851 and 15 Eunomia on July 29, 1851

And on October 24, 1851 a 3rd and 4th moon of Uranus: called Ariel and Umbriel were discovered.

So now we had 42 objects: 1 star 12 planets 18 moons and 11 asteroids. If the latest asteroids were all to be regarded as planets, it was likely to start getting silly (by 1868 the number of asteroids was to rise to 107)

The inevitable decision was taken to regard all 15 asteroids as a separate category from planets and Ceres, Pallas, Juno and Vesta were kicked out of the planetary club, just like Pluto has been kicked out today.

There are some clear parallels between the situation in the 1850s and the situation now, 4 under-sized runts had obtained planetary status, with seemingly more to follow as they were discovered creating a feeling that the currency was being devalued if all these further objects were to then be automatically awarded planetary status.

SO HOW MANY OBJECTS HAVE WE GOT IN THE SOLAR SYSTEM NOW?

Stars: 1

Planets: 8

Moons: over 80 known moons of the dwarf planets, asteroids and other small solar system bodies (87 Sylvia has 2 moons for example as does the Kuiper Belt Object KBO 2003 EL61)

AND another 162 moons orbiting around planets: Mercury has none, Venus has none, Earth has 1, Mars has 2, Jupiter has 63, Saturn has 56, Uranus has 27, Neptune has 13.

Kuiper Belt Objects: over 800 (all discovered since 1992).

Trans-Neptunian Objects: over 1000 (includes the 800+ KBOs) i,e, there are 200+ in the Scattered Disk and the Oort Cloud.

Asteroids: Hundreds of thousands of asteroids have been discovered within the solar system and the present rate of discovery is about 5000 per month. As of July 23, 2006, from a total of 338,186 registered minor planets, 134,339 have orbits known well enough to be given permanent official numbers. Of these, 13,242 have official names.

Current estimates put the total number of asteroids above 1 km in diameter in the solar system to be between 1.1 and 1.9 million

So you can see

(a) why some definitions are needed and why reclassification is necessary

(b) how totally unaware of the state of scientific knowledge the general public is and how uninformed people are when they get excited at tales of "3 new planets being discovered" and wonder if there might perhaps be more where those came from,

Finally, these issues need to be seen in the context of the 205 extra-solar planets we now know to exist and the asteroid belts that have now been detected in some of those stellar systems, Consistency being a desirable thing to achieve in science, whatever definitions and categories the IAU now adopt, they need to be applicable to every star with other objects in orbit around it, throughout the entire universe, That is the context in which Pluto's status is now being discussed,

Answer 2

Not only possible, but definite.

If the proposed definition is accepted, expect the number of planets to reach somewhere between 20 and 50 very quickly, with the number of planets eventually reaching the hundreds or even over a thousand.

The definition will be revised again to make the definition more restrictive once the number gets too absurd. Astronomers went through the same thing in the 1800's when the first four asteroids were recognized as planets (this will be Ceres's second stint as a planet). Then the number of new asteroid discoveries overwhelmed the IAU and it was decided that asteroids weren't planets.

Most people like to think of planets as something special and having too many of them diminishes the mystique.

Answer 3

Currently there is no official definition of what a planet is, If the IAU decide we need an official definition of what a planet is. That includes round rocks that orbit a star. That are neither stars nor satellites of stars. Like what they have done for those three.

There is bound to be tens more 'planets' out there.

I dont see why Ceres that used to be an asteroid gets in the club, but the other big asteroids Pallas and Vesta dont. Seems a bit unfair.

Answer 4

i greatly enjoy the thought of more planets. especially planets with orbits that do not move in the same (nearly) lateral orbit as most of the other orbits.

but something that some people in this question don't seem to understand is that the classification specification (that is still up to be voted on) does not simply say "round".

it must have enough mass to provide such a pull of gravity that it becomes round from the pull of its OWN gravity. in most cases, this would require an equator with a length of at least 500 miles. sure in all of space 500 miles is tiny, but it will disclude many of those objects which people say will be included as a planet.

i also feel that the meteoriod belt between saturn and mars should be classified as a single planet. a destroyed planet, left in shards, but a planet's remains none-the-less

the thought of so many planets makes me feel like the sun is THAT much more powerful. our sun. our solar system.

also, on charon being a planet. i like that thought as well. why not? there are solar systems that have two suns orbiting each other. there are many planets in other systems that are close enough to each other that they have a center of gravity outside the atmosphere's of each planet. to say that pluto - charon is a double planet system though, one would need to show that pluto revolves around charon as WELL as charon orbiting pluto, thus putting their centers of gravity in the same spot, equidistant from each's core

Answer 5

Ceres in one of the new planets and the other is something with 13 after it. Theyare newly formed infant planets and as space gets more spread out there should be more. If they could be located the same distance away from a sun, they could be life. All you really need is carbon, oxygena nd microrganisms for life.

We'll need a new song to remember them. USED to be Mary's Violet Eyes Make John Sit Up Nice & Pretty.

Answer 6

The biggest problem is our definition of a planet. Up until now... Pluto was questionable whether it was a planet. Now they are adding Plutos moon... doesn't that make it a moon? Not a planet? and a couple of other small bodies. I think we need a more detailed and exclusive definition of a planet, even if that means that pluto is no longer considered a planet.

Answer 7

Big Confusion is going on amongst the astronomers to your first question.
When there can be 12 planets announced now globally to public then Yes there can be possibility of more planets to be existing according to astronomers.

Answer 8

i think its great except that the only reason scientist dont like the 12 plant proposla is because if we follow the definition under this proposal, pretty soon we will have up to 100 planets sinc ethere alot alot of round objects out there orbiting the sun, Namely the TNOs and the KBOs.

Answer 9

There is proof actually, the reason they went undiscovered for so long is because scientists were looking in the wrong orbit. The outer (2) so far are orbiting in a verticular eclipse opposed to the conventional 9 other eclipses "around" the sun as we see them.

Answer 10

Its a huge controversy, with some planets being slated for removal,
and some dark stones slated for addition to the list.
I will leave that for the rock watchers...

Answer 11

I think they should define a planet and stick to those numbers.