Talk:List of Solar System objects by surface gravity

Page too long

To make this page shorter, we should use the wiki table feature. -AMK152^{(Talk • Contributions • Send message)} 11:42, April 10, 2007

Comments

Ugh. That is one hideous table. Not as it appears on the page, of course, but on the edit page; the specs do not need to be reproduced for every single cell (and some of the specs are pretty iffy themselves). I was going to add links for the planets and moons listed, but how the heck do you find them in all that cruft?

On another note, the masses and more especially the radii of the smaller moons are often very questionable, which makes the surface gravity number no more than a wild-assed guess; and below about 200km radius the shapes of the moons are so irregular that there would be no single surface gravity; the gravity would vary drastically depending upon where you were standing. At a guess, none of the figures for objects below #29 on this list are very meaningful.

What is the point of having a column for diameter in metres and one for diameter in km? I think most people who would look at this list can perform multiplication by 1000 in their heads, maybe.RandomCritic 15:52, 11 April 2007 (UTC)[reply]

I gather that the table was produced by some automatic means from a spreadsheet and then pasted directly into WP. This is something that you never, ever want to do, as it annoys people. :)

Although I've placed a warning about the reliability of the data below the line for Miranda, it could apply to several of the objects further up as well. Even the Moon has no single surface gravity, due to irregularities in density, though the variations might be more notable on smaller objects. RandomCritic 18:46, 11 April 2007 (UTC)[reply]

Where are Vesta and Pallas???? They should be around the area between Iapetus and Tethys. According to their individual pages, their surface gravities are 0.22m/s^2 and 0.18 m/s^2 respecively. —Preceding unsigned comment added by 149.101.1.120 (talk) 18:27, 8 August 2008 (UTC)[reply]

Appropriate?

Doesn't the this article constitute original research?68.48.47.241 22:19, 11 April 2007 (UTC)[reply]

If by "original research" you mean "Does this article require citations", then the answer is, of course, yes; if you mean "is this a crackpot theory pulled out of somebody's rear end", then the answer is no. It's a compilation of publicly availably data; the sources for that data should be given, but the data are in fact verifiable easily enough. RandomCritic 12:45, 12 April 2007 (UTC)[reply]

surface gravity vs gravitational acceleration

After noticing that the table is giving values with ridiculous precision, I gleefully and naively began to embark upon trying to fix up the values, without realising that I was about to knock over a can of worms. I soon found that none of the values seemed to be right for the title of the article -- surface gravity. Why was this? They appear to be giving some sort of acceleration due to gravity instead. Problems with the table as seen presently include:

Title does not match table
What radius is used?
Where do the data come from?
Ridiculous precision.

Presumably, the most interesting questions are along the lines of "how much does something weight there", and "how much velocity do you have to give an object on the surface to leave orbit". Both are related to the surface gravity (which takes into account the centrifugal force) not just the bare acceleration due to gravity. Incidentally, the distinction is not always minor - for example Saturn changes its rank in the table depending on which quantity is used. Deuar 22:42, 1 July 2007 (UTC)[reply]

Enceladus appears off

The surface gravity here for Enceladus is ten times what it is on its main entry page, making it appear much higher in this list than it should. This is because it's mass is ten times higher on this page than that of the main page (10^21 instead of 10^20).

Well caught! It's now fixed, but I wonder how many more bugs like that remain. Deuar 14:00, 22 August 2007 (UTC)[reply]

Objects without surfaces

Stars and gas giants don't have surfaces in the usual sense, so some explanation ought be given exactly what "surface gravity" means wrt them. I'm guessing the radii used are those corresponding to an atmospheric pressure of 1 bar for the gas giants and some sort of average photospheric radius for the Sun, which would be reasonable enough, but the article should explain. Orcoteuthis (talk) 16:06, 27 August 2008 (UTC)[reply]