Talk:Asteroid belt/Archive 1

Ripetute

"Ripetute"? I believe this may have been intended to say "reputedly"? At any rate, what do you supposed it is supposed to say? sugarfish 20:50 21 Jul 2003 (UTC)

It's an Italian word meaning "repeated". I've changed it to the correct English form. Chirstyn; 1 September, 2003

Asteroid Belt: Origin

Someone had asked elsewhere (I think on the Talk:Asteroid page) whence the term "Asteroid Belt". I'm writing here my research efforts.

• The first paper (according to the NASA ADS) to bear the words "Asteroid Belt" in its title is Dirk Brouwer, The problem of the Kirkwood gaps in the asteroid belt, Astronomical Journal, Vol. 68, pp. 152-159, 1963
• The first paper to use "asteroid belt" in its abstract is Frank J. Kerr and Fred L. Whipple, Possible explanations of the secular acceleration of PHOBOS and Jupiter V, Astronomical Journal, Vol. 56, p. 131, 1951
• No papers whatsoever use the German term "Asteroidengürtel" in their title or abstract (an odd result).

Urhixidur 17:11, 2005 Jan 9 (UTC)

Anyone care to explain the apparent contradiction between these two statements in the Origins section

"The current asteroid belt is believed to contain only a small fraction (by mass) of the primordial asteroid belt. Based on computer simulations, the original asteroid belt may have contained mass equivalent to the Earth. Primarily because of gravitational perturbations, most of this material was ejected from the belt within a period of about a million years of formation, leaving behind less than 0.1% of the original mass... Also, most bodies formed inside the radius of this gap were swept up by Mars (which has an aphelion out at 1.67 A.U.) or ejected by its gravitational perturbations in the early history of the Solar System."

and this statement in the Early Fifth Terrestrial Planet Theory

"There are some key problems with this hypothesis... Another [problem] is the low combined mass of the current asteroid belt, which has only a small fraction of the mass of the Earth's moon."

FusionKnight 16:28, 1 October 2007 (UTC)

I don't see a contradiction. One refers to the original mass (about that of the Earth) and the other to the current mass (about 4 percent that of the Moon). Serendi^podous 16:56, 1 October 2007 (UTC)

The contradiction that I'm referring to is that the "standard" theory states that the original asteroid belt had an earth-like mass but because of orbital perturbations caused by Jupiter, Mars sweeping up a portion of the belt, etc the mass is now much much smaller. In the next section however, the argument used to discredit the Fifth Planet Theory is that the belt has insufficient mass. If the lost mass is not an issue for the "standard" theory, why is it an issue for the Fifth Planet theory? FusionKnight 17:41, 1 October 2007 (UTC)

In the second instance, I think the concern is that the destruction of the conjectured fifth planet (long after the formation of the solar system) should have left more mass in orbit. The standard(?) model says that most of the mass that could potentially have formed a planet was tossed out during the very early history of the system, because of Jupiter's inward migration and the sweeping orbital resonances, &c. After Jupiter stopped migrating, so too would the resonances. Thus the resonances wouldn't have intersected as much of a destroyed planet's debris and more mass would be left behind. — RJH (talk) 21:16, 1 October 2007 (UTC)

The way I'm reading the article (and I could be misreading) is that the orbital resonance of Jupiter in its current position and the sweeping effect of Mars are what supposedly caused the asteroid belt to lose mass in the "standard" theory. I don't see anything in this article (I'm not saying it doesn't exist elsewhere) which refers to the migration of Jupiter being posited as the main cause of mass-loss. My bad. My eye must have skipped over that sentence in the second paragraph of the Formation section. Regardless, the area between Mars and Jupiter currently contains many areas of orbital resonance with Jupiter. Any bodies entering these areas are ejected from the belt. Orbital resonances exist anywhere two bodies have an orbital period related by a ratio of two integers. (See Orbital Resonance) This article also explicitly states that "the 4:1 orbital resonance with Jupiter, at a radius 2.06 AU, can be considered the inner boundary of the main belt... Perturbations by Jupiter send bodies straying there onto unstable orbits", so we know that orbital resonances with Jupiter have not disappeared.

As it reads now, this article is self-contradictory since it says Jupiter and Mars' influence explain missing mass in the standard theory but not in the fifth planet theory.FusionKnight 21:32, 2 October 2007 (UTC)

Why a belt?

I've wondered: why exactly are so many of the asteroids arranged in this belt? What was the origin, and why would it tend to form in its present location? Meelar (talk) 18:04, May 1, 2005 (UTC)

http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/980810a.html -- hike395 22:21, 1 May 2005 (UTC)

Asteroids go harless in sapce sometime

This is a free slot in solar system.

You may use it once.

It would be pretty heavy there for a planet-sized object, one needs really solid(strong?) body to sustain Venu,s x Jupiter..Neptune weight when occasionally combined...

Until this gap is filled, Venu,s should be kept as it is doing now...

Are you sci-fi inclined? It could be a parking orbit for a really large space-ship also...

(well, one must clean it up first from rocks and gravel, unless the space-ship is small enough to fit into Kirkwood gaps...)

S.

Belts around other stars

Wouldn't the observed extrasolar belts be more akin to the Kuiper belt than the asteroid belt? Serendipodous 12:32, 5 September 2006 (UTC)

List of largest asteroids

Shouldn't this article have a list of the largest asteroids within the main belt, sorted by size? I am happy with the new "dwarf planet" status for Ceres, but that doesn't mean that it can't still be categorized with the others. - Lawrence King 07:53, 11 September 2006 (UTC)

Such a list is over at List of noteworthy asteroids. Perhaps a case could be made to include the leading bodies from that list. A possible natural cut-off of sorts occurs after 10 Hygiea, the last of the "big four" most massive asteroids. Deuar 15:13, 11 September 2006 (UTC)

Informative

Not trying to be rude, but shouldnt you article be more informative about asteroids instead of just the asteroid belt? Just so we know at least a little about what is in the asteroid belt?

Yes, in fact Asteroid belt should be merge to Asteroid, they talk almost about the same thing ("minor planet" inside Jupiter). Tttrung 08:41, 27 October 2006 (UTC)

The article here is concerned only with the main orbital grouping of asteroids (red but not blue in the second diagram in the article), which is the "main belt", while Asteroid discusses all the minor bodies inwards of Jupiter. If you're in doubt whether this distinction is useful, have a look at the what links here page for Asteroid belt. Notice how many articles point here via the Main belt redirect. Nevertheless, you have a good point that it was not very informative about the asteroids themselves, so I've added a fairly prominent disambiguation notice in the introduction to try to remedy this. Deuar 14:24, 8 November 2006 (UTC)

Thank you for the information added. Could you give the source for all the numbers (inclination range, semi-major axis range, ...) Are these number "universally agreed", or officially defined by authoritive organisation (like IAU)? 58.187.19.142 02:59, 30 November 2006 (UTC)

I've been planning to partly amend the terminology in this article regarding the use of "main belt" − because this is actually not well defined (as you might have guessed by comments such as "below about 0.33", etc.) Hold on.... ;Regarding the proportion of asteroids in the region mentioned, that comes from a straightforward count of asteroids in an orbit database. I'll track down which one it was... Deuar 17:23, 30 November 2006 (UTC)

asteroid belt or Asteroid Belt

Someone just modified the first sentence to use "Asteroid Belt" instead of "asteriod belt." I think "asteriod belt" should not be capitalized, so I changed the first sentence back . Am I wrong? Most of the article uses the lower case, which seems to agree with the capitalization used in some reference works (i.e. M-W, OED, etc.) —RP88 02:33, 27 February 2007 (UTC) --Arctic Gnome (talk • contribs) 23:45, 11 March 2007 (UTC)

Since there are asteroid belts around multiple stars, I'm guessing it should be lower case in the general sense. If it is specifically about the Asteroid Belt around the Sun, capitalization may be grammatically correct. (Similar to the use of moon or Moon.) — RJH (talk) 17:44, 11 April 2007 (UTC)

GA Review

Good work so far - I would like to see a few fairly minor changes before the article will be ready for Good Article status.

• The lead section at present doesn't summarise the article, and instead goes into too much detail about the 'main belt'. The lead should summarise the highlights of the origin and environment sections, and the material about exactly what the 'main belt' is needs to go elsewhere - probably the 'environment' section.
  • Done. — RJH (talk) 19:02, 23 April 2007 (UTC)
• The structure of the belt is not really defined: the terms 'middle and outer belt' are used without telling us what they mean.
  • Done. — RJH (talk) 22:53, 19 April 2007 (UTC)
• Last section of the first sentence of 'Environment': "new particles must be steadily produced". If what is meant that new particles are in fact being produced, please say so - also any mechanisms suggested by which this dust is being produced. (The current text doesn't really help the reader tell whether you are talking about a corollary of a hypothesis, or a agreed and verified fact).
  • The collisions section has a discussion of dust generation. So I think this is addressed. — RJH (talk) 19:04, 23 April 2007 (UTC)
• The phrase 'asteroid family' might suggest to a reader that asteroids within a family share common composition. Can this be clarified?
  • I think this is covered now. — RJH (talk) 19:06, 23 April 2007 (UTC)
• The 'In fiction' section should be cut and the main article listed in 'See Also': it's unreferenced and basically trivia.
  • Most of this content has now been merged into the Asteroids in fiction page. — RJH (talk) 19:33, 12 April 2007 (UTC)
• References: The article relies heavily on primary sources. I would prefer to see secondary sources: summary papers from journals, books, or reliable newspaper, magazine or website articles. This might not bar being a GA but almost certainly would an FA.
  • I've never seen the use of primary sources bar an FA, at least on an astronomical topic. But I'll try to find some good-quality external links for further reading. — RJH (talk) 22:53, 19 April 2007 (UTC)

Hope these comments are useful - if there is anything you would like me to clarify, just ask and I'll get back to you right away. The Land 18:53, 4 April 2007 (UTC)

No movement on these points after one week, so I've removed the article from the candidates page and marked it as a 'fail'. However if you can address these points it will easily pass a renomination. The Land 20:15, 10 April 2007 (UTC)

It's unfortunate that the original nominator did nothing to address these concerns. But I think it's ready now. — RJH (talk) 19:09, 23 April 2007 (UTC)

GA on hold

I have reviewed this article according to the GA criteria. I felt kind of guilty for reviewing this article eight days after it was nominated, especially with the large backlog with older articles, but I'm currently covering this in my astronomy class so this was of some interest to me. Besides, it appears that this article just recently had another GA review so it doesn't deserve to wait several more weeks or a month to be reviewed again. Anyway, there are a few things that should be fixed before I pass it.

1. In third paragraph of the intro, the serial comma is used in "carbonaceous, silicate, and metallic." To maintain uniformity, add a comma after 3 Juno in "2 Pallas, 3 Juno and 4 Vesta". Same goes for "Some of the most prominent families in the main belt (in order of increasing semi-major axis) consist of the Flora, Eunoma, Koronis, Eos and Themis families." and "Eos, Koronis and Themis asteroid families" in the Families and groups section.

   I satisfied this by removing the serial comma in the first instance.

2. Add wikilinks for Sun in the intro and the History of observation sections at their first occurrence. Do the same for perturbations in the same section (it has a wikilink in the intro, but some people bypass the intro when reading the article).

   Seems like overkill, but okay.

3. "It was suggested that comets such as these may have provided a source of water for the formation of the Earth's oceans." Elaborate on this further, by detailing the fact that the comets actually impacted Earth itself to possibly bring the water. Otherwise people unaware of the process may think that oceans formed just because comets existed in this asteroid belt. This also goes for the "Main-belt comets formed within the belt outside the snow line, and these are a leading candidate for the formation of the Earth's oceans." statement in the Origins section.

   I expanded this slightly, but I didn't want the article to get too side-tracked on this topic.

4. "The currently accepted theory of planetary formation is the nebular hypothesis." Is this common knowledge, or do you think that there should be an inline citation for this? It's your choice, I won't limit the article based on this, but you can add one if you like.

   I expanded the description a little and added a citation. The link is the better choice though for people who want more details.

5. In the origin section, there is a lot of astronomical terms that could be considered confusing/jargon to unaware readers. Consider adding more wikilinks or further clarifying some terms. Don't dumb it down too much, so that it maintains its current quality, but just make a few changes you see fit.

   I attempted to clarify the terminology. Let me know if there are still issues.

6. In the rest of the article Solar System is capitalized, but in the intro it is not. Change to whatever is correct.

   Done.

7. "Finally the significant chemical differences between the asteroids is difficult to explain if they come from the same planet." I think there should be a comma after "Finally".

   Done.

8. Add a wikilink for the full date July 16, 1972 in the Exploration section.

   Done.

9. I think if you can, later on, try and expand the exploration section. This isn't necessary now, of course, but it would be interesting to have more information on this. For now, I think you should be able to add an image for one of the spacecraft from the missions listed in the section.

   The problem here is that there really hasn't been a lot of exploration of the asteroid belt by spacecraft; just some near-Earth asteroids. Most of the spacecraft were just passing through. The Dawn Mission appears to be the first true mission of exploration to the main belt, and that hasn't launched yet. I was hoping to add more later, but I'm a little reluctant to pad it right now.

Altogether, this is a well-written article with excellent sources and great images. Most of the above suggestions should be very easy to fix. I'll leave this article on hold for seven days and pass it if they are fixed. When you are done or if you have any questions, please let me know on my talk page and I'll get back to you as soon as I can. --Nehrams2020 23:38, 1 May 2007 (UTC)

Thank you. There's no problem with the delay—my experience has been that articles tagged as LONG can sometimes take up to a month. I've attempted to address your issues. — RJH (talk) 14:58, 2 May 2007 (UTC)

GA passed

I have passed this article according to the GA criteria. Excellent work on fixing all of the above suggestions, even though some of my suggestions were nitpicky they were all for improving the article. Keep adding new information with proper sources, and I hope the peer review will help to improve the article further before taking it to FAC eventually. If you have the time, please consider reviewing an article or two at GAC to help with the current backlog. --Nehrams2020 19:39, 3 May 2007 (UTC)

Thank you. — RJH (talk) 21:08, 3 May 2007 (UTC)

Unclear: 4 Vesta?

While reading this intro, I noted a list of "4 Vesta" while describing the makeup of the asteroid belt. Later on, Vesta is treated as a singular noun. Is Vesta a plural word in the intro but singular in the body of the article? Shoud it be? Or is "4 Vesta" the name of a piece of the Asteroid Belt? This is unclear and confusing to those hoping for an introduction to the Asteroid Belt.—The preceding unsigned comment was added by 66.188.125.248 (talk • contribs).

That's a good point. Unfortunately that is the standard naming convention for asteroids. I tried to add clarification to the list. — RJH (talk) 16:20, 17 June 2007 (UTC)

Unsourced addition

The following paragraph was included in the text:

As it is visible to the naked eye in pollution-free skies, Vesta, like Uranus, had most probably been seen before telescopes were invented but was too faint to be recognised as orbiting the Sun. Johannes Kepler apparently said in 1956 that he believed that there must be a planet between Mars and Jupiter. However, asteroids' (relatively) fast motion (Vesta orbits the Sun 23.16 times for every Uranus orbit) meant seventeenth and eighteenth century astronomers whose telescopes could resolve objects much fainter than 10 Hygiea's maximum brightness of +9.1 never located any asteroid for long enough to recognise it either as orbiting the Sun or as a star. By contrast, Uranus was originally identified as "34 Tauri" in 1692 and only ninety years later found to be a planet.

Unfortunately it is mostly unsourced and in many respects appears to be unconfirmed speculation (or possibly OR). The year given for Kepler's remark is clearly erroneous. So, in order for this article to retain it's GA status, I'd like to leave this here until suitable references can be found that confirm these remarks. Sorry. — RJH (talk) 17:01, 17 June 2007 (UTC)

Mass of the largest asteroids

Based on wikipedia data:

Mass of the largest main belt members

Object	Mass (1019kg)
1 Ceres	94.6
2 Pallas	22.0
4 Vesta	27.0
10 Hygiea	8.6
15 Eunomia	3.3
704 Interamnia	5.7

Total mass = 1.61 × 10²¹ kg

Belt mass = 3.0–3.6 × 10²¹ kg.

So the six largest asteroids don't add up to half the mean mass of the belt. At best the four largest are at half the low end of the estimated mass range (1.52). For future reference I changed the wording to "almost half the total mass within the main belt" rather than "about half the total mass". (Yes it's a nit. :-) — RJH (talk) 19:38, 10 July 2007 (UTC)

New topics

Candidates for addition to this article.

Basaltic asteroids

Article might need to include a discussion of basalt asteroids.

• Than, Ker (August 21, 2007). "Strange Asteroids Baffle Scientists". Hubble News Desk. Retrieved 2006-05-24.
• Lazzaro, D.; et al. (2000). "Discovery of a Basaltic Asteroid in the Outer Main Belt". Science. 288 (5473): 2033–2035. Retrieved 2007-08-22. {{cite journal}}: Explicit use of et al. in: |author= (help)
• Duffard, R.; Roig, F. "Two new basaltic asteroids in the Outer Main Belt". arXiv:0704.0230.{{cite arXiv}}: CS1 maint: multiple names: authors list (link)

— RJH (talk) 16:25, 22 August 2007 (UTC)

298 Baptistina

Interesting story about a possible connection between the breakup of 298 Baptistina and the formation of the Chicxulub Crater:

• Staff (September 5, 2007). "Breakup event in the main asteroid belt likely caused dinosaur extinction 65 million years ago". Physorg. Retrieved 2007-09-06.

— RJH (talk) 16:09, 6 September 2007 (UTC)

This definetly needs to be worked in, as it is is an event caused by the asteroid belt that had a big impact (no pun intended) on life on our planet. Megalodon99 Talk 19:03, 7 October 2007 (UTC)

Fifth terrestrial planet theory

Seems a bit out there and doesn't really fit in with its section. Is there a better location to place it? Serendi^podous 19:48, 2 October 2007 (UTC)

OK. Reworked it. Serendi^podous 20:13, 2 October 2007 (UTC)

Meteorites

Some mention of the asteroids' connection to meteorites needs to be made. Serendi^podous 20:12, 2 October 2007 (UTC)

'Collisions' section: "...and some of the debris from collisions can form meteoroids that enter the Earth's atmosphere." Meteorites are a subset of the meteoroids. — RJH (talk) 15:55, 3 October 2007 (UTC)

Direction of Orbit

Does anybody have any sources/data on what direction asteroids orbit the sun? I've seen it mentioned in passing that they orbit in either direction, but it would be nice to have some numbers showing how many orbit which direction. I'll do some searching, but if anybody else knows... FusionKnight 02:39, 6 October 2007 (UTC)

Almost all orbit in the prograde direction like all the major and dwarf planets. For a list of the retrograde ones see here (I'm not sure if it's complete, but it certainly shows that the number of retrograde asteroids is tiny in comparison with the several hundred thousand known in total). Deuar 11:10, 6 October 2007 (UTC)

Pictures

Why are there only a few pictures in the article, and only one of an asteroid? There need to be more for this to be a nice article (in my opinion, which is often wrong). I have a collection of rather interesting pictures from Galaxy zoo. However, they do not really show the asteroids themselves, so I did not upload any, and I will wait till someone says something to do so. (Here is a forum topic from GZ that has lots of asteroid pics. http://www.galaxyzooforum.org/index.php?topic=3393.0 ) I started that topic. Megalodon99 Talk 19:08, 7 October 2007 (UTC)

Perhaps because the asteroid belt as a whole isn't very photogenic? We could include an image of the zodiacal light, since that is discussed in the article. Also it might be interesting if there were good images in the Commons of S-type and M-type meteorites for comparison. It's too bad we don't have a useable image of (25143) Itokawa; that would be an ideal illustration of a rubble-pile asteroid for the collisions section. — RJH (talk) 01:51, 15 October 2007 (UTC)

Zodiacal light would be a good idea for Collisions. There should be a picture of at least one asteroid, maybe Gaspra. Serendi^podous 20:14, 17 October 2007 (UTC)

name: A. Belt vs A. belt

which one is the correct form? Shouldn't "b" be capitalized since it is a name? Nergaal (talk) 01:34, 23 January 2008 (UTC)

Not a proper name, I think. Nouns in English (as opposed to, say, German) are not capitalized unless they refer to a particular named object. Other stars than the Sun will presumably be found to have "main belts" too: regions where orbits are nearly stable against the perturbations of major planets, so objects can collect and remain there there over time. It's kind of a close call—I would say "The Solar Main Belt" is proper, (as would be "The Alpha Centauri Main Belt", if there is one). Anyhow, I believe it is typically not capitalized (like "the sun", which is common but definitely incorrect, I think per IAU decree). "What's in a name?" :) Wwheaton (talk) 19:12, 23 April 2009 (UTC)

Why do you discuss about small-small things here?

GoodGod21 (talk) 06:06, 14 October 2021 (UTC)

Collisions versus agglomeration

I would like to see a cite for the sentence that reads "collisions that occur at low relative speeds may also join two asteroids together." Really? Most collisions are at at least many hundreds of m/s up to typical impact speeds of 5 km/s -- does two asteroids ever join together 'softly' the way this reads?? —Preceding unsigned comment added by 128.148.116.88 (talk) 20:54, 11 November 2009 (UTC)

At one point the document says that the total mass of the belt is 4% of the mass of Earth's Moon. Another point in the document says that 99.9% of the mass of the belt has been lost. A quick Google calculation yields: ((mass of the Moon * 0.04) / (1 - 0.999)) / Earth mass = 0.492125876. Therefore, the original mass of the Asteroid Belt is estimated to be half an Earth mass. Another quick Google calculation yields mass of Mars / Earth mass = 0.107446849. Now that I have established that the Asteroid Belt could have been formed from a planet-sized object, I want to attack the idea that the rocks of the belt could be formed from accretion. Ceres, the largest object inhabiting the belt, has a mass of 0.00015 times that of Earth, and a surface gravity of 0.028 m/s^2. The Earth has a surface gravity of 9.81 m/s^2, or 350 times that of Ceres. The gravity of any planet is zero at the center. We approximate the pressure at the center of Ceres (from http://physics.info/pressure/practice.shtml) with (3.0 * (((6.67E-11 N) * (m^2)) / (kg^2)) * ((9.43E20 kg)^2)) / ((8 * Pi * (487.3E3 m))^4) = 7909.06946 pascals. The document on Metamorphic rock says that 1500 bar is required to form this rock, which is the type of rock that I would expect to form from dust in space. Note that 1500 bars = 150000000 pascals, and (1500 bars) / (7909.06946 pascals) = 18965.5687, that is, the pressure at the center of Ceres is 19 thousand times too small to form rock. Therefore, it is unlikely that the Asteroid Belt was not formed from a demolished planet. QED. This article is pablum for the masses, and should be removed for being unscientific. 98.81.162.188 (talk) 03:00, 28 February 2014 (UTC)

Rock is a type of material. Pressure is not required to form it; it was already present in the accretion disc (actually, already in the planetary nebula). Nothing has been QED'ed by you. --JorisvS (talk) 08:28, 28 February 2014 (UTC)

Rock forms under zero pressure in space? Would I then have to accept that the hand of God was at play? Or is the position that space is filled with random rock that readily collects into tight orbital planes that are separated by light-years? Please provide calculations to support your position, as words alone have zero value. 98.81.179.13 (talk) 13:34, 28 February 2014 (UTC)

The early (more massive) asteroid belt was scattered and materiel eroded away by Jupiter because Jupiter is the most massive planet and accreted first. This is also the reason Mars is somewhat on the wimpy size. The average density of Ceres is only 2.1 g/cm3 and most of the heavier elements (what astronomers casually refer to as rock) will be near the core. -- Kheider (talk) 15:17, 28 February 2014 (UTC)

My arguments are: the Asteroid Belt is what remains from a planet-sized object destroyed in the past; the rocks and dust that constitute the Asteroid Belt were not formed in space spontaneously with near-zero-pressure. I presume rock, whether massive or miniscule, is the product of planetary accretion. Planets are the factories that produce rock from the matter stars eject. Gravity is the machinery in planets that form rock, and with little gravity - no rock forms, as the pressure threshold required to form the crystalline structure is not exceeded. The unsubstantiated proposition that the rocks in the Asteroid Belt were the product of accretion under what-amounts-to zero pressure is fallacious, and abhorrent in that it "teaches" something akin to magic. I appear to be arguing with blind consensus, and as history has repeatedly shown, consensus is the enemy of science. Dissent is the factory that produces science, and argument is the mechanism that conceives a new understanding. I see no arguments here, just parroting of past statements with no understanding what those statements mean. 98.81.167.61 (talk) 02:44, 1 March 2014 (UTC)

Not rocks as in "boulders", but nano-sized particles consisting of rock. Follow that link if you don't understand this. --JorisvS (talk) 18:40, 28 February 2014 (UTC)

Rock is a crystalline structure. If by "rock" you mean a loose dust pillow made of "nano-sized particles", then I think we have nothing more to discuss as you have no intellectual integrity. 98.81.167.61 (talk) 02:44, 1 March 2014 (UTC)

A) Personal attacks such as that are not allowed, for good reasons. B) One can also have dust-sized particles of ices. You should review cosmic dust and interstellar cloud (look for "dust"). --JorisvS (talk) 11:24, 1 March 2014 (UTC)

Collisions, "Meteorites" content conflict with 298 Baptistina page

The following information conflicts with more recent information as mentioned in the 298 Baptistina page: "A September 2007 study has suggested that a large-body collision undergone by the asteroid 298 Baptistina sent a number of fragments into the inner Solar System. The impacts of these fragments are believed to have created both Tycho crater on the Moon and Chicxulub crater in Mexico, the relict of the massive impact which is believed to have triggered the extinction of the dinosaurs 65 million years ago". While the 298 Baptistina page (based on more recent research) states: "It was considered the possible source of the impactor said to have caused the extinction of the dinosaurs, a possibility ruled out by the Wide-field Infrared Survey Explorer in 2011." etc.86.84.5.177 (talk) 17:27, 22 February 2013 (UTC)

Origin of the term "belt"

The earliest quote Google Books finds is Mémoires de la Société royale des sciences de Liège, 1843, which reads in part "[...] the plane of the ecliptic and beyond Saturn or, conceivably, in the asteroid belt as suggested by Oort." But since Oort lived 1900-1992, this must be a mistake ("1943" instead of 1843).

More reliable are:

• Robert W. Gibbes et al., Eds., Proceedings of the American Association for the Advancement of Science, First Meeting, Held at Philadephia, September 1848, 1849, p. 60 (On the Zodiacs of the Asteroids): "Prof. [J. S.] Hubbard of the Washington Observatory stated to the Association that he was then engaged in computing the Zodiacs of the Asteroids. The term Zodiacs, as here applied, he defined as referring to the zone or belt within which are included all possible geocentric positions of the particular asteroid in question: and the object in thus determining these belts was to facilitate researches into the past history of these remarkable bodies; since in most cases, the question of identity of a missing star, with any asteroid, may be settled at once by a simple inspection of the Zodiacs."

• Alexander von Humboldt, Cosmos: A Sketch of a Physical Description of the Universe, Vol. I, Harper & Brothers, New York (NY), 1850, p. 44: "[...] and the regular appearance, about the 13th of November and the 11th of August, of shooting stars, which probably form part of a belt of asteroids intersecting the Earth's orbit and moving with planetary velocity" (translated from the German by E. C. Otté). The 1845 edition does not use that expression.

• Robert James Mann, A guide to the knowledge of the heavens, Jarrold, 1852, p. 171 and in the 1853 edition, p. 216: "The orbits of the asteroids are placed in a wide belt of space, extending between the extremes of [...]"

• The Christian Examiner, Vol. LVII (July-November 1854), p. 219: "For in Professor Peirce's demonstration of this hypothesis, he shows that the ring is sustained by the power of the exterior satellites; and remarks that the belt of asteroids just within the powerful masses of Jupiter and Saturn is in that place where it is most nearly possible for a ring to be sustained about the Sun." The article qives its reference as Benjamin Peirce, On the constitution of Saturn's ring, Astronomical Journal, Vol. 2, No. 3, pp. 17-19 (16 June 1851), but that article never mentions the word "belt". However, see The Edinburgh New Philosophical Journal 1857 quote, below.

• Joseph Allen Galbraith and Samuel Haughton, Manual of Astronomy, Longman, Brown, Green, and Longmans, London, 1855, pp. 13-14: "In the annexed figure, which is drawn to scale, the belt of Asteroids enclosed between the orbits of Flora and Euphrosyne is represented in its true position and breadth, lying between Mars and Jupiter. [...] There are, without doubt, many more bodies than the 33 mentioned in the Table circulating round the Sun within the limits of this belt [...]"

• Thomas Anderson, William Jardine, John Hutton Balfour, Henry Darwin Rogers, (Eds.), The Edinburgh New Philosophical Journal, Vol. 5 (January-April 1857), p. 191: "[Professor Peirce] then observed that the analogy between the ring of Saturn and the belt of the asteroids was worthy of notice."

• Hannah Mary Bouvier Peterson, Bouvier's Familiar Astronomy, Childs & Peterson, 1857, p. 57: "[The asteroids] are situated in a belt or zone only about nine hundred million of miles in width."

• Jacob Ennis, The Origin of the Stars, 1867, p. 292: "[The asteroids] are probably a few hundred in number, about eighty having been discovered in the last twenty years, and they are included within a belt about 150,000,000 miles broad. In view of the dimensions of the rings which formed the planets as given in the thirtieth section, we cannot suppose that a single ring occupied all the space within the asteroid belt."

• Albert Taylor Bledsoe, Editor, The Southern Review, Vol. VIII, No. 15 (July 1870), p. 165: "If this [nebular] hypothesis be true, it is at least conceivable that while in one stage of the condensation great planets should be formed, in another period there would result a multitude of small bodies similar in all respects to those which constitute the great asteroid belt".

In conclusion, the term "belt" (as a span of latitude) had long been in use to designate the zodiac (and features of Jupiter). "Asteroid belt" seems to have been used for the first time by a translator of Humboldt, in 1850, but that may be accidental (the original German text does not use the German word "gürtel" ("belt"); "asteroidengürtel" appears in the 1879 edition, though). Widespread use apparently begins ca. 1851, probably under the aegis of American astronomer Benjamin Peirce, and was undoubtedly influenced by the concept of belt or ring borrowed from the nebular hypothesis. Urhixidur (talk) 17:59, 21 November 2008 (UTC)

Digging further into German sources, G. A. Jahn, > Unterhaltungen für Dilettanten und Freunde der Astronomie, Geographie und Meteorologie, Leipzig, 1852, p. 340: "[...] so dass man jetzt deren 20 kennt die man als Stellvertreter eines grössern Planeten zwischen der Mars und der Jupitersbahn betrachten kann obgleich sie einen so breiten Gürtel bilden dass die in der Bode schen Reihe für sie bestimmte Entfernung nicht mehr passt", which my poor German translates roughly as "[...] so that one knows some 20 [planetoids] now, and placing them between the orbits of Mars and Jupiter forms so broad a belt that the distance determined in Bode's Law no longer has any meaning." Not very convincing, and no other German book before that date (1852) mentions "gürtel" along with "Ceres, Pallas, Vesta". Urhixidur (talk) 18:54, 21 November 2008 (UTC)

Rotation Rate

The cited article about a lower limit on rotation rates (Rossi, Alessandro (May 20, 2004). "The mysteries of the asteroid rotation day". The Spaceguard Foundation. http://spaceguard.esa.int/tumblingstone/issues/current/eng/ast-day.htm. Retrieved 2007-04-09.) is no longer available online. It seems to be contradicted by this article: http://www.nature.com/nature/journal/v386/n6621/abs/386154a0.html which states that "Moreover, our calculations suggest that the observed trend in the mean spin frequency for different classes of asteroids (2.2 d–1for C-type asteroids, 2.5 d–1 for S-type, and 4.0 d–1 for M-type) is due to increasing mean density, rather than increasing material strength." Can we find a current reference for the currently cited article, and should we include the contrary view in the article? Delrayva (talk) 04:36, 23 December 2009 (UTC)

Composition

Why do the proportions of the three types of asteroids add up to about 103 percent. Rounding certainly can't be the error factor here.

C-type "more than 75 percent" S-type "17 percent" M-type "10 percent" —Preceding unsigned comment added by 159.121.204.129 (talk) 19:35, 27 May 2010 (UTC)

Because the third number was also determined indepently, and not by substracting the first two from one hundred. --129.13.72.198 (talk) 11:49, 29 April 2011 (UTC)

"Dust particles"

"The remaining bodies range down to the size of a dust particle."

Are dust paricles possible? I thought they´d be wiped out of the solar system by the pressure of the solar radiation. --129.13.72.198 (talk) 11:43, 29 April 2011 (UTC)

You might want to read the Collisions section. In short, it's an ongoing cycle of dust generation through collisions and loss from solar radiation.—RJH (talk) 14:39, 29 April 2011 (UTC)

"Size chart of the largest Asteroids"

Someone should create a size chart like the one for the Solar System article. Start with the largest, Ceres, and end with the known smallest one. A size chart for the Centaurs would be neat too. Thank you. Chuck 17:42, 20 July 2012 (UTC) — Preceding unsigned comment added by Triton66 (talk • contribs)

Composition

Many asteroids are known to be partly composed of ices through their densities, notably Ceres itself. So why would it be so unexpected to find water (vapor)? Evidence of (past) water has even been found on dry Vesta. --JorisvS (talk) 15:25, 23 January 2014 (UTC)

@JorisvS - Thanks for your comments - text has been updated (after a closer look at the cited reference) as follows => The finding is unexpected because comets, not asteroids, are typically considered to "sprout jets and plumes". According to one of the scientists, "The lines are becoming more and more blurred between comets and asteroids."< ref name="NASA-20140122">Harrington, J.D. (22 January 2014). "Herschel Telescope Detects Water on Dwarf Planet - Release 14-021". NASA. Retrieved 22 January 2014.</ref> - in any case - thanks again for your comments - and - Enjoy! :) Drbogdan (talk) 16:14, 23 January 2014 (UTC)

Yes, definitely better:). Thank you. --JorisvS (talk) 16:15, 23 January 2014 (UTC)

It's still a rather silly thing to say, isn't it, since comets are defined by "spouting jets and plumes"? So they're saying it's surprising that Ceres spouts jets and plumes, because only things that spout jets and plumes are usually thought to spout jets & plumes. It's a badly worded catch for a news release, not something we should be quoting. The point they're trying to make is that while some smaller, outer asteroids were known to display cometary activity, prompting the IAU in 2006 to reject the distinction between asteroid and comet by creating the category SSSB, now the largest asteroid (and a DP rather than a SSSB) has been shown to exhibit similar behaviour, blurring the lines even further. Certainly we can find a wording that isn't intellectually challenged. — kwami (talk) 21:13, 1 March 2014 (UTC)

Collision count

If collisions occur "once every 10 million years", 4 billion years should see 400 collisions. That seems like a low number for the population to "bear little resemblance to the original". Login54321 (talk) 13:09, 15 June 2015 (UTC)

That's linear thinking. The collision rate was substantially higher in the past. --JorisvS (talk) 13:29, 15 June 2015 (UTC)

The reference used in the article timed-out on me, but I think it is every ~10 million years for each individual asteroid and different groups/families will have different rates. Hildas, such as 2483 Guinevere in a 3:2 resonance with Jupiter are generally only going to impact another asteroid when near perihelia and thus are about 3.5 times safer than MBAs that are full time residents of the main-belt. -- Kheider (talk) 16:21, 15 June 2015 (UTC)

I agree, it is written to suggest 400 collisions over 4 billion years. The article is either wrong or misleading, it needs to be changed to explain this properly. Stub Mandrel (talk) 13:35, 26 October 2018 (UTC)

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Distance from the sun

Shouldn't it made clear how far from the sun (in km/AU) the asteroid belt is? I imagine that would be useful to most readers. —Atvelonis (talk) 19:26, 17 August 2016 (UTC)

I agree! There's a lot of space "between the orbits of the planets Jupiter and Mars;" but I would also include the distance in miles as well. 2600:8800:784:8F00:C23F:D5FF:FEC4:D51D (talk) 18:52, 28 December 2019 (UTC)

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Splitting the Article?

At what point would it make sense to split the article? I think we'd need one for asteroid belts in general (origin, composition...) and our asteroid belt specifically (the Sol-4 belt? The Trans-Martian Belt? The Martian-Jovian Belt?). Humanity probably has enough information about asteroid belts in general now to justify a separate article, even if we haven't found any extra-solar belts yet. It wouldn't be topical to discuss, for example, how asteroid belts orbit double stars in the current article, but it is still article-worthy.

We haven't seen any asteroid belts in other systems yet. Protoplanary discs, yes. Circumstellar discs (Kuiper belts) yes. Not other asteroid belts. Serendi^podous 10:28, 4 September 2017 (UTC)

The Moon is not the only moon; i am inclined to assume the local asteroid belt is not the only asteroid belt.^{[citation needed]} Assuming Serendipodous is correct, though, here's a little "sandbox" proposed addition to the article in lieu of a separate article for asteroid belts in general:

The asteroid belt in our solar system is the only one currently known to exist, although hypotheses about its formation suggest the likelihood that others exist in other star systems, and humankind merely has yet to discover those distant asteroid belts. — Preceding unsigned comment added by 71.121.143.175 (talk) 07:33, 17 October 2017 (UTC)

What would qualify one particular circumstellar disc as "an asteroid belt" and another as not one? Presumably, for the term to be useful, you'd need some definition that excludes the Kuiper belt and the similar belts discovered around other stars, not to mention things like protoplanetary gas discs. But what definition?

Obviously there are rules that would work (inside the orbit of all gas giants but outside at least one rocky planet; 40%+ mass in minor planets; something to do with shared orbital elements, whatever), but is any such distinction well-motivated and useful? And, more to the point, is any such definition actually in use, and verifiable in reliable sources?

If not, there really isn't much to say but "The term is sometimes applied in a loose way to other circumstellar discs, both real and fictional, that are in various different ways similar to the Sun's main asteroid belt." Which hardly seems like something you could write a separate article about. --157.131.246.136 (talk) 21:01, 20 April 2019 (UTC)

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This page is not detailed enough and there have been several enquiries on other pages, if anyone is willing to edit please send me a message on my talk pageGamer11166 (talk) 18:15, 2 February 2018 (UTC) This is optional and if not edited I will put it up for deletion. thank you Gamer11166 (talk) 18:15, 2 February 2018 (UTC)

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M-Type asteroid frequency

The article states M-Type asteroids are 10% of the bodies in the asteroid belt, with no attribution for that claim. Table 5 in this paper https://www.sciencedirect.com/science/article/pii/S0019103513002923#t0025 suggests that M-type asteroids are 3% of the mass of the asteroid belt. These are measuring somewhat different things (mass vs count), so they aren't necessarily in conflict, but I'd be concerned about that 10%. The 3% should probably be added, and the 10% should at least have a citation if it stays in. Only putting this in talk though because I'm not terribly familiar with wikipedia editing/norms. — Preceding unsigned comment added by 128.114.68.72 (talk) 17:53, 9 April 2019 (UTC)

Missing text

Editors please examine the missing text in the article: the unfinished sentence just above the ToC. — Preceding unsigned comment added by 80.112.145.106 (talk) 12:52, 1 November 2019 (UTC)

Conflicting information about total mass

In the heading chapter it is stated that "The total mass of the asteroid belt is approximately 18% that of the Moon, or 22% that of Pluto, and roughly twice that of Pluto's moon Charon (whose diameter is 1200 km)." However, later in the article (under the heading "Characteristics") there's the following sentence: "The total mass of the asteroid belt is estimated to be 2.39×1021 kilograms, which is just 3% of the mass of the Moon.[56] The four largest objects, Ceres, 4 Vesta, 2 Pallas, and 10 Hygiea, account for maybe 40% of the belt's total mass, with 30% accounted for by Ceres alone.[57][5]". These can't be both true, and it appears that the latter is correct, cf. e.g. https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S1743921315008388 176.72.240.17 (talk) 08:01, 14 August 2020 (UTC)

Thanks for spotting it. Serendi^podous 12:43, 14 August 2020 (UTC)

The four largest objects, Ceres, 4 Vesta, 2 Pallas, and 10 Hygiea, account for maybe 62% of the belt's total mass (9.38+2.59+2.01+0.83=14.81/23.90=0.62*100%=62%) — Preceding unsigned comment added by 176.120.103.204 (talk) 20:49, 7 September 2020 (UTC)