Talk:Asteroid belt

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)

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)

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)