Asteroid belt
Theasteroid beltormain beltis a ring of small and large rocks and dust between theorbitsofMarsandJupiter.The biggest object in the asteroid belt isCeres,adwarf planet.TheKirkwood gapsseparate the asteroid belt into several groups.
Mostasteroidsorbit at 2 to 3 times the distance between Earth and the Sun. Planets that are "inside" - or before - the asteroid belt (which means they are closer to the sun) are calledinner planets.Planets that are "outside" - that is, after - the asteroid belt are calledouter planets:soMercury,Venus,Earth,andMarsareinner planets,whileJupiter,Saturn,UranusandNeptuneare theouter planets.
The asteroid belt is a disc. Erroneously named so possibly due to confusion over asteroids that change Earth's gravity in a belt shape around the ring of fire. The worlds largest island arc chain at centre known as a hotspot.
Origin[change|change source]
In 1802, shortly after discovering2 Pallas,Heinrich Olberssuggested toWilliam HerschelthatCeresandPallaswere fragments of a much larger planet that once occupied the Mars–Jupiter region, this planet having suffered an internal explosion or a cometary impact many million years before.[1]Thishypothesishas fallen from favor. The large amount of energy needed to destroy a planet, and with the belt's low combined mass (only about 4% of the mass of theMoon) do not support the hypothesis. Also, the significant chemical differences between the asteroids are difficult to explain if they come from the same planet.[2]Today, most scientists accept that the asteroids never formed a planet at all.
TheSolar System formedwhen a cloud of interstellar dust and gas collapsed under the influence ofgravityto form the Sun andplanetesimals,and eventually the planets.[3]This gravitational accretion led to the formation of the rocky planets and thegas giants.
Planetesimalsin the region which would become the asteroid belt were too strongly disturbed by Jupiter's gravity to form a planet. Instead they continued to orbit the Sun as before, while occasionally colliding.[4]In regions where the velocity of the collisions was too high, the shattering of planetesimals was more common than accretion,[5]preventing the formation of planet-sized bodies.
References[change|change source]
- ↑"A brief history of asteroid spotting".Open2.net.Archived fromthe originalon 2011-08-07.Retrieved2007-05-15.
- ↑Masetti, M.; and Mukai, K. (2005)."Origin of the Asteroid Belt".NASA Goddard Spaceflight Center.Retrieved2007-04-25.
{{cite web}}:CS1 maint: multiple names: authors list (link) - ↑Watanabe, Susan (2001)."Mysteries of the Solar Nebula".NASA. Archived fromthe originalon 2012-01-17.Retrieved2007-04-02.
- ↑Petit, J.-M.; Morbidelli, A.; and Chambers, J. (2001)."The primordial excitation and clearing of the Asteroid Belt"(PDF).Icarus.153(2): 338–347.Bibcode:2001Icar..153..338P.doi:10.1006/icar.2001.6702.Archived(PDF)from the original on 21 February 2007.Retrieved2007-03-22.
{{cite journal}}:CS1 maint: multiple names: authors list (link) - ↑Edgar, R.; and Artymowicz, P. (2004)."Pumping of a planetesimal disc by a rapidly migrating planet"(PDF).Monthly Notices of the Royal Astronomical Society.354(3): 769–772.arXiv:astro-ph/0409017.Bibcode:2004MNRAS.354..769E.doi:10.1111/j.1365-2966.2004.08238.x.S2CID18355985.Archived fromthe original(PDF)on 2007-06-21.Retrieved2007-04-16.
{{cite journal}}:CS1 maint: multiple names: authors list (link)
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