The Astronomy Discussion Thread

[raikage]

Another thing to keep in mind is the actual distance between objects in space:

(the distance between the Earth and the Moon)

[Kensuke]

8, 9 or 12+ planets in Solar System? 2,500 astronomers has gathered in Prague to figure that out, because of recent discoveries of bigger objects that Pluto, smallest of the original nine planets.

The IAU draft resolution recognises eight "classical" planets - Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune - three "plutons" - Pluto, Charon and UB313 - and the asteroid Ceres.

Charon is currently described as a moon of Pluto, but because of its size some experts consider it a twin planet.

...

More objects are likely to be announced as planets in the future. The IAU has a "watchlist" of at least a dozen other potential candidates that could become planets once more is known about their sizes and orbits.

These include the distant objects Sedna, Orcus, Quaoar and 2003 EL61 and the asteroids Vesta, Pallas and Hygiea.

Source: http://news.bbc.co.uk/2/hi/science/nature/4795755.stm

I find that little weird, while big objects found in Kuiper Belt can be considered planets, but I don't think Ceres or any other asteroids should be called planets. Even Ceres is less than a half of the size of Pluto.

[mantidor]

The more I learned about Pluto the more I felt it wasn't a real planet. As I understand this began with the discovery of Xena last year which is bigger than pluto, if Xena is not considered a planet Pluto can't be considered a planet either. Its just a problem of semantics though, if Pluto stops being considered a planet what name would it have? asteroid? or just kuiper belt object?

[Kamui4356]

Originally Posted by mantidor

The more I learned about Pluto the more I felt it wasn't a real planet. As I understand this began with the discovery of Xena last year which is bigger than pluto, if Xena is not considered a planet Pluto can't be considered a planet either. Its just a problem of semantics though, if Pluto stops being considered a planet what name would it have? asteroid? or just kuiper belt object?

Pluto would be a kuiper belt object if stripped of it's planet status.

The thing is, Pluto may not be bigger, but it does have Charon, it's sort of moon. Though Pluto might not be a planet on size alone, it should count because of that.

I think any final decision should wait until we send a mission to pluto. I know Nasa was going to send a probe in a few years, but I'm not sure if it's still on track or was canceled.

[JanthraX^]

Another thing is where is the edge of the Solar system, is it where Solar winds hit intergalctic winds.

I do believe ceres is too small to be a planet, also i thought the kupier belt was an area of asteriods not something that is a ring = O, around the Sun

[Kensuke]

Originally Posted by Kamui4356

I know Nasa was going to send a probe in a few years, but I'm not sure if it's still on track or was canceled.

Do you mean New Horizons? It was lauched January 2006.

It is the fastest spacecraft ever, after passing Jupiter its speed is over 21 km/s, but that is less than 0.01 % of speed of light, we have a long way to go before even to seriously think about interstellar travel.

[Loniat]

In my lame n00bish opinion, objects should be considered planets only if they had some kind of atmosphere (even moons could be included into that, why not have moon-planets?).

[Jinto]

I'ld say moons aren't planets, because they are not direct satellites of the star. And I'ld only count those objects as planets that are typical starborn objects. For example in our solarsystem the inner planets are objects with a high density (and solid), then there are the gas-type planets (not that dense)... and then there should be nothing, but coincidently our sun was born from a supernove so there is also the coyper belt, but objects out of this belt are not really made by sun. Thatswhy I wouldn't count Pluto as planet. But thats a matter of taste or definition I suppose.

[Kamui4356]

Originally Posted by Kensuke

Do you mean New Horizons? It was lauched January 2006.

It is the fastest spacecraft ever, after passing Jupiter its speed is over 21 km/s, but that is less than 0.01 % of speed of light, we have a long way to go before even to seriously think about interstellar travel.

Ah, they already launched it? I must have either missed it or forgotten about it. *As I hope I didn't make a comment on the mission in this very thread, and forgot *

As for what's a planet, perhaps pluto shouldn't be considered one, but since it's been for so long, why not just make an exception for it? Or just make this xena a planet as well, but give it a better name. Unfortunately, it seems all the good Roman gods have been taken, so let's just go with Eruruu, or maybe Kozue?.

[Aoie_Emesai]

Originally Posted by Catgirls

National Geographic News has a nice little piece called Hubble's Top Ten Discoveries.

They're not the most visually appealing Hubble work, but significant none-the-less (sometimes ugly trumps beauty).

I've also been quite fascinated with the SOHO (Extreme ultraviolet Imaging Telescope) work:



-> http://umbra.nascom.nasa.gov/eit/EIT.html
-> http://soho.nascom.nasa.gov/
-> http://umbra.nascom.nasa.gov/eit/eit_full_res.html

Like Kamui said, the hubble is quite amazing, eh? Space is so amazing because it's just like nature, beauty in it's simplest form. Visually pleasing to the eyes, just like anime; eye candy, to be more specific. I'm sure even aliens (outer space creatures, not people from other countries) would say "how nice space is."

[SvenTheSweeper]

Quote:
The IAU draft resolution recognises eight "classical" planets - Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune - three "plutons" - Pluto, Charon and UB313 - and the asteroid Ceres.

Charon is currently described as a moon of Pluto, but because of its size some experts consider it a twin planet.

...

More objects are likely to be announced as planets in the future. The IAU has a "watchlist" of at least a dozen other potential candidates that could become planets once more is known about their sizes and orbits.

These include the distant objects Sedna, Orcus, Quaoar and 2003 EL61 and the asteroids Vesta, Pallas and Hygiea.

Source: http://news.bbc.co.uk/2/hi/science/nature/4795755.stm

I'm surprised no one has brought this up, maybe it's off topic.

What would the IAU draft resolution do to all the anime and manga that use planets (e.g. Sailor Moon) or the western zodiac (e.g. Saint Saya) as themes?

Would it be interesting or not to revise the canon (for a definition of canon in the fictional sense see http://en.wikipedia.org/wiki/Canon_%28fiction%29) of a particular series based on these new revisions?

Speculations welcomed.

[Jinto]

I, personally, see the new classified planet Ceres more as a planet then i.e. Pluto/Charon. I do believe that there was a 5th inner planet once, but it became destroyed, and the remaining belt of debris contains Ceres (which possibly is a part of that former planet). Well thats just my "taste" regarding planets. I don't really care if they classify other solar objects as planets. Its only about names (and some astronomers who feel more important then)

[C.A.]

Well, the theory has been around for some time that the asteroid belt could be a planet that failed to form or a planet that was smashed to pieces by an object.

[Kamui4356]

Originally Posted by C.A.

Well, the theory has been around for some time that the asteroid belt could be a planet that failed to form or a planet that was smashed to pieces by an object.

Though if either of those were the case, wouldn't the astroid belt be more tightly packed? When we think of an astroid belt, we generally imagine something like in The empire strikes back, bu the reality is, it's pretty dispersed.

If it was a destroyed plaent especially, I'd think there would be a denser leading concentration of larger astroids where the planet was, and progressively smaller and more dispersed astroids trailing it. I could be way off on that though, but from what I know the gravity of smashed objects tends to keep the fragments close together. Look as the comet that smashed into jupiter for example.

[C.A.]

Hmmm from what I remembered, the comet that stuck Jupiter was torn into 7 major fragments and hit Jupiter in 7 spots across the southern hemisphere. Their initial debris clouds from their impacts, stretched horizontally across 1/5 of of the southern atmosphere, which I think is quite a huge distance. I don't think their gravity held them close to one another.

The recent Cassini probe which visited Saturn brought back data that shows how gravity forces between Saturn and its moons kept the rings in shape. The rings themselves were also theorised that they may be a single moon or moons in the past.

The gravitation forces between Saturn and its orbiting moons pull the rings in such a way that results in an outcome I can only explain with an example lol:

Its similar to dropping a drop of dye in a cup of water thats stirred in one direction. The drop of dye hits the water and starts swirling in the same direction as the water, the dye will eventually form a circle.

Over many years, the gravitational forces pull the remains of a planet/moon or a planet/moon that failed during its formation, in the same way as the drop of dye in a swirling cup of water.

And for the density of asteroids, this will eventually settle over the years as well, when the rocks collide with each other at high speeds they break up into smaller fragments. It will eventually reach an equal density in the entire ring.

[i0td]

Originally Posted by SvenTheSweeper

Would it be interesting or not to revise the canon (for a definition of canon in the fictional sense see http://en.wikipedia.org/wiki/Canon_%28fiction%29) of a particular series based on these new revisions?

Speculations welcomed.

I really doubt there would be any revision to older anime series even if drastic changes were to be made. The classical planets, as mentioned briefly in the article, and especially the original six (Earth, mercury, venus, mars, jupiter, saturn) are going to remain front stage planets for a long time. They have been for such a long period of human history already and they will continue to have a strong impact in storytelling, anime or otherwise. And even if the IAU makes a definite ruling and names a few new planets in the process, it would still be surprising to me if these new planets make an appearance in future series anytime soon. Tradition will play a big role here.

Seeing as you mentioned Sailor Moon, can you imagine a Sailor Xena debuting soon?

[Aoie_Emesai]

Originally Posted by i0td

I really doubt there would be any revision to older anime series even if drastic changes were to be made. The classical planets, as mentioned briefly in the article, and especially the original six (Earth, mercury, venus, mars, jupiter, saturn) are going to remain front stage planets for a long time. They have been for such a long period of human history already and they will continue to have a strong impact in storytelling, anime or otherwise. And even if the IAU makes a definite ruling and names a few new planets in the process, it would still be surprising to me if these new planets make an appearance in future series anytime soon. Tradition will play a big role here.

Seeing as you mentioned Sailor Moon, can you imagine a Sailor Xena debuting soon?

Anime in space? How wonderful, sorta of old but wonderful. Of course im kidding now.

ps: Next question, Aliens?

[Loniat]

Originally Posted by Jinto Lin

I'ld say moons aren't planets, because they are not direct satellites of the star. And I'ld only count those objects as planets that are typical starborn objects. For example in our solarsystem the inner planets are objects with a high density (and solid), then there are the gas-type planets (not that dense)... and then there should be nothing, but coincidently our sun was born from a supernove so there is also the coyper belt, but objects out of this belt are not really made by sun. Thatswhy I wouldn't count Pluto as planet. But thats a matter of taste or definition I suppose.

I don't think our sun was formed after a supernova.

[Kamui4356]

Originally Posted by C.A.

Hmmm from what I remembered, the comet that stuck Jupiter was torn into 7 major fragments and hit Jupiter in 7 spots across the southern hemisphere. Their initial debris clouds from their impacts, stretched horizontally across 1/5 of of the southern atmosphere, which I think is quite a huge distance. I don't think their gravity held them close to one another.

A huge distance by our standards sure, but by cosmic standards, not so much. The astroid belt is far more dispersed. Now, it's true that over time it would have dispersed, but I doubt it would have done so to the point we couldn't tell there was once a large object that broke apart.

Though I realize the comet wasn't the best analogy, as it was broken apart only a few years before it impacted jupiter, while if the astroid belt is the remains of a planet, it would have occured billions of years ago.

[C.A.]

Originally Posted by Kamui4356

Though I realize the comet wasn't the best analogy, as it was broken apart only a few years before it impacted jupiter, while if the astroid belt is the remains of a planet, it would have occured billions of years ago.

Yea, that's why some scientists think that instead of being blasted apart, it could be a planet that failed during formation, billions of years ago, during the formation of the solar system.

It didn't have enough mass to have a gravity strong enough to compact itself into a 'ball'. So it formed numerous lumps instead and got dispersed by the gravitational forces of Mars and Jupiter.

One thing that supports the theory of not having enough mass, is that the combined mass of all the asteriods would make up only 4% of the Earth's moon, with Ceres itself making 1/4 of the total mass.(Mass info taken from Wikipedia)

With such a small amount of mass, it can't form anything, or couldn't have existed as a single object of such size. The gravitational forces between Mars and Jupiter simply wouldn't allow it to form anything.