Asteroïde: Verskil tussen weergawes
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’n '''Asteroïde''' of '''asteroïed''' is ’n soort [[kleinplaneet]] wat om die [[Son]] wentel, veral in die binnenste [[Sonnestelsel]]. Toe kleinplanete in die buitenste Sonnestelsel ontdek is, is gevind hul oppervlakke bestaan gewoonlik uit [[Vlugtigheid|vlugtige]] elemente of samestellings, nes dié van [[Komeet|komete]]. Dié voorwerpe is dus dikwels onderskei van dié in die [[asteroïdegordel]].<ref>{{cite web |url=http://ssd.jpl.nasa.gov/?asteroids |title=Asteroids |website=NASA – Jet Propulsion Laboratory |accessdate=13 September 2010}}</ref> In hierdie artikel verwys die term "asteroïde" na die kleinplanete van die binneste Sonnestelsel, insluitende dié wat ’n [[wentelbaan]] met [[Jupiter]] deel.
[[Lêer:(253) mathilde.jpg|duimnael|270px|links|253 Mathilde is 'n asteroïde met ’n deursnee van sowat 50 km.]]
[[Beeld:Asteroid Belt.svg|thumb|’n Diagram van die Sonnestelsel se asteroïdegordel.]]
Daar is miljoene asteroïdes, waarvan baie vermoedelik die oorblyfsels is van [[planetesimale]], liggame in die jong Son se [[sonnewel]] wat nooit groot genoeg geword het om [[planete]] te word nie.<ref>{{cite web |website=CNEOS |title=Frequently Asked Questions (FAQs) – What Are Asteroids And Comets? |url=http://neo.jpl.nasa.gov/faq/#ast |accessdate=13 September 2010 |archiveurl= https://web.archive.org/web/20100909210213/http://neo.jpl.nasa.gov/faq/ |archivedate= 9 September 2010 <!--DASHBot-->| deadurl= no}}</ref> Die oorgrote meerderheid van bekende asteroïdes kom voor in die hoofasteroïdegordel tussen die wentelbane van [[Mars]] en Jupiter, of deel ’n wentelbaan met Jupiter (die [[Trojaan (sterrekunde)|Jupiter-trojane]]). Daar is egter taamlike groot families asteroïdes met ander wentelbane, insluitende die [[naby-aarde-voorwerp]]e. Individuele asteroïdes word geklassifiseer volgens hul kenmerkende [[Emissielyn|spektra]]. Die meeste val in drie hoofgroepe: C-, M- en S-tipe asteroïdes. Hulle is genoem na en word gewoonlik verbind met onderskeidelik [[koolstof]], [[metaal]] en [[silikaat]] (klipagtig). Asteroïdes se groottes wissel aansienlik; die grootste een, [[Ceres (dwergplaneet)|Ceres]], se deursnee is amper 1 000 km.
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Die [[Verenigde Nasies]] het [[30 Junie]] as Internasionale Asteroïdedag verklaar om die publiek oor asteroïdes op te voed. Dié datum herdenk die [[Toengoeska-voorval|Toengoeska-asteroïde-impak]] op 30 Junie 1908 in [[Siberië]], [[Rusland]].<ref>{{cite press release |url=http://www.unoosa.org/oosa/en/informationfor/media/2016-unis-os-478.html |title=United Nations General Assembly proclaims 30 June as International Asteroid Day |date=7 Desember 2016 |id=UNIS/OS/478 |website=United Nations Office for Outer Space Affairs}}</ref><ref>{{cite web |url=https://www.un.org/ga/search/view_doc.asp?symbol=A/71/492 |others=Rapporteur: Awale Ali Kullane |title=International cooperation in the peaceful uses of outer space |date=25 October 2016 |access-date=6 Desember 2016 |website=United Nations}}</ref>
In April 2018 het die B612 Foundation, wat hom onder meer toespits op verdediging teen asteroïdes, berig "die kans is 100 persent dat ons deur ’n verwoestende asteroïde getref sal word, maar ons is nie 100 persent seker wanneer nie".<ref name="DS-20180428">{{cite news |last=Harper |first=Paul |title=Earth will be hit by asteroid with 100% Certainty ...experts have warned it is "100pc certain" Earth will be devastated by an asteroid as millions are hurling towards the planet undetected |url=https://www.dailystar.co.uk/news/world-news/699177/Asteroids-earth-space-apocalypse-meteor-B612-Foundation |date=28 April 2018 |work=Daily Star |accessdate=26 November 2018 }}</ref><ref name="INQ-20180428">{{cite news |last=Homer |first=Aaron |title=Earth Will Be Hit By An Asteroid With 100 Percent Certainty, Says Space-Watching Group B612 – The group of scientists and former astronauts is devoted to defending the planet from a space apocalypse. |url=https://www.inquisitr.com/4881237/earth-will-be-hit-by-an-asteroid-with-100-percent-certainty-says-space-watching-group-b612/ |date=28 April 2018 |work=Inquisitr |accessdate=26 November 2018 }}</ref> Ook die fisikus [[Stephen Hawking]] het in 2018 in sy laaste boek, ''Brief Answers to the Big Questions'', gemeen ’n asteroïdebotsing is die grootste bedreiging wat ons planeet in die gesig staar.<ref name="WP-20181015">{{cite news |last=Stanley-Becker |first=Isaac |title=Stephen Hawking feared race of ‘superhumans’ able to manipulate their own DNA |url=https://www.washingtonpost.com/news/morning-mix/wp/2018/10/15/stephen-hawking-feared-race-of-superhumans-able-to-manipulate-their-own-dna/ |date=15 Oktober 2018 |work=The Washington Post |accessdate=26 November 2018 }}</ref><ref name="QZ-20181014">{{cite web |last=Haldevang |first=Max de |title=Stephen Hawking left us bold predictions on AI, superhumans, and aliens |url=https://qz.com/1423685/stephen-hawking-says-superhumans-will-take-over-ai-is-a-threat-and-humans-will-conquer-space/ |date=14 Oktober 2018 |work=Quartz |accessdate=26 November 2018 }}</ref><ref name="NYT-20180618">{{cite news |last=Bogdan |first=Dennis |title=\Better Way To Avoid Devastating Asteroids Needed? |url=https://www.nytimes.com/2018/06/14/science/asteroids-nasa-nathan-myhrvold.html#permid=27500228:27506217 |date=18 Junie 2018 |work=The New York Times |deadurl=no |archiveurl= |archivedate= |accessdate=26 November 2018 }}</ref>
In Junie 2018 het die [[VSA]] se nasionale wetenskap-en-tegnologieraad gewaarsku dat Amerika onvoorbereid op ’n asteroïde-impak is. Die raad het die "[https://www.whitehouse.gov/wp-content/uploads/2018/06/National-Near-Earth-Object-Preparedness-Strategy-and-Action-Plan-23-pages-1MB.pdf National Near-Earth Object Preparedness Strategy Action Plan]" ontwikkel en uitgereik om beter daarop voor te berei.<ref name="WH-20180621">{{cite web |author=Staff |title=National Near-Earth Object Preparedness Strategy Action Plan |url=https://www.whitehouse.gov/wp-content/uploads/2018/06/National-Near-Earth-Object-Preparedness-Strategy-and-Action-Plan-23-pages-1MB.pdf |format=PDF |date=21 June 2018 |work=White House |accessdate=22 June 2018 }}</ref><ref name="GIZ-20180621">{{cite news |last=Mandelbaum |first=Ryan F. |title=America Isn't Ready to Handle a Catastrophic Asteroid Impact, New Report Warns |url=https://gizmodo.com/america-isnt-ready-to-handle-a-catastrophic-asteroid-im-1827014709 |date=21 June 2018 |work=Gizmodo |accessdate=22 Junie 2018 }}</ref><ref name="ICARUS-220180522">{{cite journal |last=Myhrvold |first=Nathan |authorlink=Nathan Myhrvold |title=An empirical examination of WISE/NEOWISE asteroid analysis and results |url=https://www.sciencedirect.com/science/article/pii/S0019103516307643 |date=22 Mei 2018 |journal=Icarus|volume=314 |pages=64–97 |doi=10.1016/j.icarus.2018.05.004 |accessdate=22 June 2018 |bibcode=2018Icar..314...64M }}</ref><ref name="NYT-20180614c">{{cite news |last=Chang |first=Kenneth |title=Asteroids and Adversaries: Challenging What NASA Knows About Space Rocks |url=https://www.nytimes.com/2018/06/14/science/asteroids-nasa-nathan-myhrvold.html#permid=27500228:27506217 |date=14 Junie 2018 |work=The New York Times |accessdate=22 Junie 2018 }}</ref><ref name="NYT-20180614">{{cite news |last=Chang |first=Kenneth |title=Asteroids and Adversaries: Challenging What NASA Knows About Space Rocks |quote= Two years ago, NASA dismissed and mocked an amateur’s criticisms of its asteroids database. Now Nathan Myhrvold is back, and his papers have passed peer review. |url=https://www.nytimes.com/2018/06/14/science/asteroids-nasa-nathan-myhrvold.html |date=14 Junie 2018 |work=The New York Times |accessdate=26 November 2018 }}</ref> Volgens kennersgetuienis in 2013 in die Amerikaanse kongres het [[Nasa]] minstens vyf jaar van voorbereiding nodig voordat ’n sending van stapel gestuur kan word om ’n asteroïde te onderskep.<ref name="US-Congress-20130410">{{cite web |author=U.S.Congress |title=Threats From Space: a Review of U.S. Government Efforts to Track and mitigate Asteroids and Meteors (Part I and Part II) – Hearing Before the Committee on Science, Space, and Technology House of Representatives One Hundred Thirteenth Congress First Session |url=http://www.gpo.gov/fdsys/pkg/CHRG-113hhrg80552/pdf/CHRG-113hhrg80552.pdf |date=19 Maart 2013 |page=147 |work=United States Congress |accessdate=26 November 2018 }}</ref>
== Ontdekking ==
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