Asteroïde: Verskil tussen weergawes

[[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.]]

 

Asteroïdes verskil van komete en [[meteoroïde]]s. Die verskil tussen asteroïdes en komete is hul samestelling: Komete bestaan hoofsaaklik uit stof en ys en asteroïdes uit rots en minerale. Laasgenoemde het nader aan die Son ontstaan en bevat dus nie ys nie.<ref>{{cite web |title=What is the difference between an asteroid and a comet?|url=http://coolcosmos.ipac.caltech.edu/ask/181-What-is-the-difference-between-an-asteroid-and-a-comet- |website=Cool Cosmos |publisher=Infrared Processing and Analysis Center |accessdate=13 Augustus 2016}}</ref> Die verskil tussen asteroïdes en meteoroïdes is hul grootte: Meteoroïdes het ’n deursnee van ’n meter of kleiner, terwyl asteroïdes se deursnee groter as ’n meter is.<ref name=Rubin2010>{{cite journal |last1=Rubin |first1=Alan E. |last2=Grossman |first2=Jeffrey N. |title=Meteorite and meteoroid: new comprehensive definitions |journal=Meteoritics and Planetary Science |date=Januarie 2010 |volume=45 |issue=1 |pages=114–122 |bibcode=2010M&PS...45..114R |doi=10.1111/j.1945-5100.2009.01009.x |doi-access=free}}</ref> Meteoroïdes kan dieselfde samestelling as óf asteroïdes óf komete hê.<ref name="Universe Today">{{cite web |title=What is the difference between asteroids and meteorites? |url=http://www.universetoday.com/36398/what-is-the-difference-between-asteroids-and-meteorites/ |website=Universe Today |last=Atkinson |first=Nancy |date=2 Junie 2015 |accessdate=13 Augustus 2016}}</ref>

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 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>

| url=http://neo.jpl.nasa.gov/programs/

| title=Near Earth Object Search Programs

<ref>{{cite web

| url=https://cneos.jpl.nasa.gov/stats/site_all.html

| archive-url=https://web.archive.org/web/20181228041653/https://cneos.jpl.nasa.gov/stats/site_all.html

| archive-date=28 Desember 2018

* Lincoln Near-Earth Asteroid Research (LINEAR)

* Near-Earth Asteroid Tracking (NEAT)

|department=Astronomy (rubriek)}}</ref> Toe sterrekundiges meer klein liggame begin vind wat permanent anderkant Jupiter bly, dit wat nou sentoure genoem word, het hulle dit as tradisionele asteroïdes beskou, hoewel gedebatteer is oor of hulle as asteroïdes beskou moet word of as ’n nuwe soort voorwerp. Toe die eerste [[trans-Neptunus-voorwerp]] (buiten [[Pluto]]), [[15760 Albion|Albion]], in 1992 ontdek word en veral toe groot getalle soortgelyke voorwerpe gevind word, is nuwe terme uitgedink om die vraagstuk te ontduik: [[Kuipergordel]]voorwerp, trans-Neptunus-voorwerp, [[Verstrooide skyf|verstrooideskyfvoorwerp]], ens. Hulle kom in die koue buitewyke van die Sonnestelsel voor waar yse [[Vaste stof|vaste stowwe]] bly en komeetagtige voorwerpe nie na verwagting veel komeetaktiwiteit toon nie; as sentoure of trans-Neptunus-voorwerpe naby die Son kom, sal hul vlugtige yse sublimeer. Hulle sal dan volgens tradisie as komete geklassifiseer word en nie as asteroïdes nie.

 

 

Die kleinplanete anderkant Jupiter se wentelbaan word soms "asteroïdes" genoem. Die term word egter al hoe meer beperk tot kleinplanete in die binneste Sonnestelsel.<ref name=KBOasteroids/> In hierdie artikel word die woord se betekenis dus merendeels beperk tot die klassieke asteroïdes: voorwerpe in die [[asteroïdegordel]], [[Trojaan (sterrekunde)|Jupiter-trojane]] en [[naby-aarde-voorwerp]]e.

| bibcode=2002AJ....123..549P |bibcode-access=free

| arxiv=astro-ph/0110258

 

 

Pallas is buitengewoon omdat dit, soos Uranus, op sy kant roteer, met ’n groot [[Baanhelling|hoek tussen sy rotasie-as en wentelvlak]].<ref name="Torppa1996">{{cite journal |first1=J. |last1=Torppa |first2=M. |last2=Kaasalainen |first3=T. |last3=Michałowski |first4=T. |last4=Kwiatkowski |first5=A. |last5=Kryszczyńska |first6=P. |last6=Denchev |first7=R. |last7=Kowalski

| doi=10.1016/S0019-1035(03)00146-5 |display-authors=3}}</ref> Sy samestelling is soortgelyk aan dié van Ceres: baie [[koolstof]] en [[silikon]] en dalk gedeeltelik gedifferensieerd.<ref>{{cite journal |title=The composition of asteroid 2 Pallas and its relation to primitive meteorites |author=Larson, H.P. |author2=Feierberg, M.A. |author3=Lebofsky, L.A. |last-author-amp=yes |date=1983 |bibcode=1983Icar...56..398L |volume=56 |issue=3 |page=398 |journal=Icarus |doi=10.1016/0019-1035(83)90161-6}}</ref> Pallas is die hoofvoorwerp van die Pallas-familie asteroïdes.

 

 

{| class="wikitable"

|doi=10.1007/s11208-005-0033-2

|bibcode=2005SoSyR..39..176P

|archiveurl=https://web.archive.org/web/20140703074335/http://iau-comm4.jpl.nasa.gov/EPM2004.pdf

|archivedate=3 Julie 2014}}</ref>]]

|publisher=The Spaceguard Foundation

|accessdate=9 April 2007

|archiveurl=https://web.archive.org/web/20060512060350/http://spaceguard.iasf-roma.inaf.it/tumblingstone/issues/current/eng/ast-day.htm

|archivedate=12 Mei 2006

| title=Ice confirmed on an asteroid

| publisher=Science News | url=http://www.sciencenews.org/view/generic/id/48174/title/Ice_confirmed_on_an_asteroid

| last = Atkinson

| first = Nancy

| accessdate = 11 Oktober 2009

| url = http://spacefellowship.com/2009/10/08/more-water-out-there-ice-found-on-an-asteroid/

 

In Oktober 2013 is water vir die eerste keer op ’n ekstrasolêre liggaam waargeneem – op ’n asteroïde wat om die [[witdwerg]] [[GD 61]] wentel.<ref>{{cite web |last=Mack |first=Eric |title=Newly spotted wet asteroids point to far-flung Earth-like planets |url=http://news.cnet.com/8301-17938_105-57607077-1/newly-spotted-wet-asteroids-point-to-far-flung-earth-like-planets/ |publisher=CNET}}</ref> Op 22 Januarie 2014 het wetenskaplikes van die [[Europese Ruimteagentskap]] (ESA) verslag gedoen oor die eerste besliste waarneming van [[waterdamp]] op die dwergplaneet Ceres in die asteroïdegordel.<ref name="KüppersO’Rourke2014">{{cite journal |display-authors=3 |last1=Küppers |first1=Michael |last2=O’Rourke |first2=Laurence |last3=Bockelée-Morvan |first3=Dominique |last4=Zakharov |first4=Vladimir |last5=Lee |first5=Seungwon |last6=von Allmen |first6=Paul |last7=Carry |first7=Benoît |last8=Teyssier |first8=David |last9=Marston |first9=Anthony |last10=Müller |first10=Thomas |last11=Crovisier |first11=Jacques |last12=Barucci |first12=M. Antonietta |last13=Moreno |first13=Raphael |title=Localized sources of water vapour on the dwarf planet (1) Ceres |journal=Nature |volume=505 |issue=7484 |date=2014 |pages=525–527 |doi=10.1038/nature12918 |bibcode = 2014Natur.505..525K |pmid=24451541}}</ref> Die waarneming is gedoen met die [[infrarooi]]geriewe van die [[Herschel-ruimtesterrewag]].<ref name="NASA-20140122">{{cite web |last1=Harrington |first1=J.D. |title=Herschel Telescope Detects Water on Dwarf Planet – Release 14-021 |url=http://www.nasa.gov/press/2014/january/herschel-telescope-detects-water-on-dwarf-planet |date=22 Januarie 2014 |work=NASA |accessdate=22 Januarie 2014 }}</ref> Dié bevinding was onverwags omdat komete, en nie asteroïdes nie, gewoonlik met "spuitstrale en pluime" verbind word. Volgens een van die wetenskaplikes "vervaag die verskille tussen komete en asteroïdes al hoe meer".<ref name="NASA-20140122" />

|}

 

 

==Verkenning==