h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Entry: Ceres- Dwarf Planet - A13943261
Author: shagbark - U170775

Since the IAU chose Ceres as a member of its new category, I felt h2g2 needed an article about this Dwarf Planet.

Fine article, well done!

Is it worth describing the size of Ceres in layman's terms (i.e. x times the size of the Earth/Moon/Wales)?

Icy

I don't have time to research that now but it sounds like a good idea.

"It would be the first spacecraft ever to orbit two different objects."

I thought the Moon missions orbited the Earth to pick up some speed before breaking Earth orbit and entering the Moon's orbit?

annoyingly that definition of a dwarf planet also fits Earth and many other planets.

Damm planetary dynamists


quick typo notes ...

Jupitar >> Jupiter (couple of occations)
If Earth were put in that orbitour world >> orbit our


You briefly mention Keppler in passing. Mention could be given to the fact that he made his discoveries because he had orginally set out to find the tune to Phythogous's music of the spheres.

A large chunk of your article repeats Researcher beeline's article on Discovery of the Asteroid Belt article, which already is an Edited Entry, and it's in H2G2's tour of the solar system.

the goddess of agriculture,grain,maternal love,. ->agriculture, grain, and maternal love.

The acceptance of the qualifier 'thousands' in relation to asteroids depends on one thinking of only the ones larger than 1 km, which is arbitrary. Just like there didn't used to be a definition of planet, there isn't a standard one for asteroid yet. Since there's no standard definition of asteroid, there are possibly hundreds of thousands, or even billions of them. I think it's worth mentioning something like this, if you are going to talk about asteroids in general so much.

Spherical (last instance)->spherical

in reference to post #5 you have not grasped the meaning of
section(c) in the definition. At least ninety-nine percent of Earth's orbit has been cleared of primordial matter. While in the asteroid belt or Kuiper belt this is not the case.
This definition stands in opposition to then definition of a Planet
one of whose characdteristics is it has cleared out its orbit.

I think the mass of Ceres might not be right. In the entry, the mass is stated as 9.5x10^26 kg, but that sounds too big. http://www.nineplanets.org/asteroids.html suggests that the mass is 8.7x10^20 kg. Wiki uses 9.5x10^20 kg.

In the first sentence, would it be worth mentioning what IAU stands for?

Other than that, I like this entry. I do like Bode's law, too. When you graph it, the straight line running through all the planets (and asteroid belt) just looks so neat.

Given that whatever w***ers who wrote that rule think that it is linguistically possible for a dwarf planet not to be a planet, I think that any their rather ambiguas rule is rather open to interpretation.

In terms of the mass of Ceres
my mind can't really comprehend the diference between ten to the twentieth power and ten to the twenty-sixth. I somehow read something wrong the first time. After checking several websites I chose a value got from NASA. I hope it is acceptable. I have been meaning to make these other changes but haven't gotten a Round TUIT ( now where could I have put the thing )

I have appended a tag to say Bodes Law material from Beeline.
Next thing I want to tackle is the size issue. A hyperlink would be good as well as a statement comparing it to Europe.

updated 3 September,2006 Note berlin to London

Hi shagbark,

This is an interesting article, particularly given the controversy surrounding Pluto at the moment.

I'm not quite convinced that the material on Bode's Law should be included - it doesn't really add to the entry, which is about the "dwarf planet" itself and not the asteroid belt as a whole.

I would suggest that it would be better to expand the piece about "the facts" instead. This paragraph should be expanded a bit more into plain English, and comparisons made to more familiar things. The facts on their own don't give the reader any feel for the object. e.g. "If you were to walk on the surface of Ceres, you would feel a gravitational acceleration of 0.27 m/s2, which is almost 50 times less than the gravitational force on Earth."

Cheers

Woodpigeon

OK woodpigeon, just for you I have shortened the Bodes law material.
(Actually moving it to another article maked not for review)
As to the facts section, I am following the style used in the other planetary entries in the edited guide. they limit that section to statistics without explanation. I am doing likewise.
However I did Try to put the size into perspective and note that it is to small to hold an atmosphere. I am still searching for some artwork I can link to showing the relative size.

Is there any grammar or spelling that needs correction?

This certainly makes a good interesting read

I wonder if 'differentiated interior' might warrant a very short explanatory footnote.

I also wonder if 'terrestrial planet' might also warrant one.

When you quote Bill Nye, perhaps you could add in parenthesis (the science guy) and add a link - or, you know, something.
http://www.nyelabs.com/

Having said that - I might just be missing some obvious point - why exactly the comparison to Mercury? Not that I have a problem with it - just curious:
>>Bill Nye said recently that 'if Pluto had the same orbit as Mercury it would boil away until there was nothing left.' If Earth were put in that orbit our world would lose it's oceans but keep it's Surface. Since the mantle of Ceres is mostly frozen water if Ceres were in Mercury's orbit all that would remain would be the core making it about three-fourth of its current size.<<

Also would help to identify Lucy McFadden
http://www.astro.umd.edu/people/mcfadden.html

>>Jupitar it would have continued acreting<<
*Jupiter* and *accreting*

>>This craft would use an ion engine and would reach Vesta in 2010 spend a few month there then break orbit and go to Ceres establishing an orbit there in 2016.<<
How about: 'Using an ion engine, this craft would reach Vesta in 2020 and spend a few months there in orbit before leaving for Ceres. It is expected to arrive at Ceres and establish an orbit by 2016.'

What about an external link for ion engine
http://www.bbc.co.uk/science/space/exploration/futurespaceflight/ionengines.shtml

Well done

The point Bill Nye was trying to make was why demote Pluto when the smallest of the terrestrial planets Mercury is not demoted.
Mercury (see A396812) with a diameter just under 4900 KM has only five point six percent of the earths mass but it is all rock.
The dwarf Planets(I would even venture to say all dwarf planets) Have a sizable percentage of thir mass in ice. I also just noticed that the other planetary entries use Equatorial Radius rather than diameter. I wounder if I should do likewise.

I am adding the link to ion engines and will footnote Mcfaddens credentials.

Ahh Ok - good explanation - I missed that point. If there are others like myself, perhaps you could add a very brief segue since both pluto and mercury seem to appear without warning.

Thanks