View source for Astronomy:Torino scale

{{Short description|Measure for the hazard from asteroids and comets}}
The '''Torino scale''' is a method for categorizing the [[Astronomy:Impact event|impact]] hazard associated with [[Astronomy:Near-Earth object|near-Earth object]]s (NEOs) such as [[Astronomy:Asteroid|asteroid]]s and [[Astronomy:Comet|comet]]s.
It is intended as a communication tool for [[Astronomy:Astronomer|astronomer]]s and the public to assess the seriousness of collision predictions, by combining probability statistics and known kinetic damage potentials into a single threat value. The [[Palermo Technical Impact Hazard Scale]] is a similar, but more complex scale.

Near-Earth objects with a Torino scale of 1 are discovered several times a year, and may last a few weeks until they have a longer [[Astronomy:Observation arc|observation arc]] that eliminates any possibility of a collision. The only two objects on the Torino Scale that have ever ranked higher are asteroids [[Astronomy:99942 Apophis|99942 Apophis]], which had a rating of 4 for four days in late 2004, the highest recorded rating, and {{mpl|(144898) 2004 VD|17}}, with a historical rating of 2 from February to May of 2006.

==Overview==
[[Image:Torino scale.svg|right|400px|thumb|Torino Scale. The scale in metres is the approximate diameter of an asteroid with a typical collision velocity.]]
The Torino Scale uses an integer scale from 0 to 10. A 0 indicates an object has a negligibly small chance of collision with the [[Astronomy:Earth|Earth]], compared with the usual "background noise" of collision events, or is too small to penetrate Earth's atmosphere intact. A 10 indicates that a collision is certain, and the impacting object is large enough to precipitate a global disaster.

An object is assigned a 0 to 10 value based on its collision probability and the [[Physics:Kinetic energy|kinetic energy]] (expressed in [[Physics:TNT equivalent|megatons of TNT]]) of the possible collision.

The Torino Scale is defined only for potential impacts less than 100 years in the future.

"For an object with multiple potential collisions on a set of dates, a Torino Scale value should be determined for each date. It may be convenient to summarize such an object by the greatest Torino Scale value within the set."<ref name=nasa>{{cite web|url=http://impact.arc.nasa.gov/torino.cfm |title=Torino Impact Scale |access-date=2007-03-11 |url-status=dead |archive-url=https://web.archive.org/web/20070224184143/http://impact.arc.nasa.gov/torino.cfm |archive-date=2007-02-24 }} Torino Impact Scale (NASA Ames)</ref>

==History and naming==
The Torino Scale was created by Professor [[Biography:Richard P. Binzel|Richard P. Binzel]] in the Department of Earth, Atmospheric, and Planetary Sciences, at the [[Organization:Massachusetts Institute of Technology|Massachusetts Institute of Technology]] (MIT). The first version, called "A Near-Earth Object Hazard Index", was presented at a {{wipe|United Nations}} conference in 1995 and was published by Binzel in the subsequent conference proceedings (''Annals of the New York Academy of Sciences,'' volume 822, 1997.)

A revised version of the "Hazard Index" was presented at a June 1999 international conference on NEOs held in Torino ([[Place:Turin|Turin]]), Italy. The conference participants voted to adopt the revised version, where the bestowed name "Torino Scale" recognizes the spirit of international cooperation displayed at that conference toward research efforts to understand the hazards posed by NEOs. ("Torino Scale" is the proper usage, not "Turin Scale.")<ref name=nasa/>

Due to exaggerated press coverage of Level 1 asteroids, a rewording of the Torino Scale was published in 2005, adding more details and renaming the categories: in particular, Level 1 was changed from "Events meriting careful monitoring" to "Normal".

The Torino Scale has served as the model for the [[Astronomy:Rio scale|Rio scale]] which quantifies the validity and societal impact of SETI data.<ref name="Rio scale">{{cite web | url=http://avsport.org/IAA/rioscale.htm | title=The Rio Scale | publisher=International Academy of Astronautics | access-date=2016-08-29 | archive-date=2016-09-02 | archive-url=https://web.archive.org/web/20160902040412/http://avsport.org/IAA/riocalc.htm | url-status=dead }}</ref>

== Current Torino scale ==

The Torino Scale also uses a color code scale: white, green, yellow, orange, red. Each color code has an overall meaning:<ref name="Torino-scale"/>

{|class="wikitable"
! colspan=2|No hazard (white)
|-style="background:#fff"
| style="text-align:center" | <big>'''0'''</big>
| The likelihood of a collision is zero, or is so low as to be effectively zero. Also applies to small objects such as meteors and bodies that burn up in the atmosphere as well as infrequent meteorite falls that rarely cause damage.
|-
! colspan=2|Normal (green)
|-
| style="background:#00c000;color:#fff;text-align:center"|<big>'''1'''</big>
| style="background:#e6f9e6"|A routine discovery in which a pass near Earth is predicted that poses no unusual level of danger. Current calculations show a collision is extremely unlikely with no cause for public attention or public concern. New telescopic observations very likely will lead to reassignment to Level 0.
|-
! colspan=2|Meriting attention by astronomers (yellow)
|-
| style="background:#ffe000;text-align:center"|<big>'''2'''</big>
| style="background:#fffce6"|A discovery, which may become routine with expanded searches, of an object making a somewhat close but not highly unusual pass near Earth. While meriting attention by astronomers, there is no cause for public attention or public concern as an actual collision is still very unlikely. New telescopic observations very likely will lead to reassignment to Level 0.
|-
| style="background:#ffe000;text-align:center"|<big>'''3'''</big>
| style="background:#fffce6"|A close encounter, meriting attention by astronomers. Current calculations give a 1% or greater chance of collision capable of ''localized destruction''. Most likely, new telescopic observations will lead to reassignment to Level 0. Attention by public and by public officials is merited if the encounter is less than a decade away.
|-
| style="background:#ffe000;text-align:center"|<big>'''4'''</big>
| style="background:#fffce6"|A close encounter, meriting attention by astronomers. Current calculations give a 1% or greater chance of collision capable of ''regional devastation''. Most likely, new telescopic observations will lead to reassignment to Level 0. Attention by public and by public officials is merited if the encounter is less than a decade away.
|-
! colspan=2|Threatening (orange)
|-
| style="background:#ff8000;color:#fff;text-align:center"|<big>'''5'''</big>
| style="background:#fff2e6"|A close encounter posing a serious, but still uncertain threat of regional devastation. Even though most objects of this level will be lowered to Level 0, critical attention by astronomers is still needed to determine conclusively whether a collision will occur. If the encounter is less than a decade away, governmental contingency planning may be warranted.
|-
| style="background:#ff8000;color:#fff;text-align:center"|<big>'''6'''</big>
| style="background:#fff2e6"|A close encounter by a large object posing a serious but still uncertain threat of a global catastrophe. Critical attention by astronomers is needed to determine conclusively whether a collision will occur. If the encounter is less than three decades away, governmental contingency planning may be warranted. Some objects of this level may be lowered to Level 1 or 2, if the chances of collision decrease.
|-
| style="background:#ff8000;color:#fff;text-align:center"|<big>'''7'''</big>
| style="background:#fff2e6"|A very close encounter by a large object, which if occurring this century, poses an unprecedented but still uncertain threat of a global catastrophe. For such a threat in the next 100 years, international contingency planning is warranted, especially to determine urgently and conclusively whether a collision will occur.
|-
! colspan=2|Certain Collisions (red)
|-
| style="background:#f00;color:#fff;text-align:center"|<big>'''8'''</big>
| style="background:#ffe6e6"|A collision is certain, capable of causing localized destruction for an impact over land or possibly a tsunami if close offshore. Such events occur on average between once per 50 years and once per several thousand years.
|-
| style="background:#f00;color:#fff;text-align:center"|<big>'''9'''</big>
| style="background:#ffe6e6"|A collision is certain, capable of causing unprecedented regional devastation for a land impact or the threat of a major tsunami for an ocean impact. Such events occur on average between once per 10,000 years and once per 100,000 years.
|-
| style="background:#f00;color:#fff;text-align:center"|<big>'''10'''</big>
| style="background:#ffe6e6"|A collision is certain, capable of causing global climatic catastrophe that may threaten the future of life as we know it, whether impacting land or ocean. Such events occur on average once per 100,000 years, or less often.
|}

No incoming object has ever been rated above level 4, though over all of Earth's history impacts have spanned the full range of damage described by the scale.

==Actual impacts and impact energy comparisons==
The [[Earth:Chicxulub crater|Chicxulub impact]], believed by most scientists to have been a significant factor in the [[Earth:Cretaceous–Paleogene extinction event|extinction of the non-avian dinosaurs]], has been estimated at 100 million (10<sup>8</sup>) megatons, or Torino Scale 10. The impacts which created the Barringer Crater and the 1908 [[Physics:Tunguska event|Tunguska event]] are both estimated to be in the 3–10 [[Physics:TNT equivalent|megaton]] range,<ref name=Sandia>{{cite web|url=https://www.eurekalert.org/pub_releases/2007-12/dnl-sso121807.php|title=Sandia supercomputers offer new explanation of Tunguska disaster|publisher=Sandia National Laboratories|date=December 17, 2007|access-date=February 21, 2021|archive-date=June 8, 2021|archive-url=https://web.archive.org/web/20210608194615/https://www.eurekalert.org/pub_releases/2007-12/dnl-sso121807.php|url-status=live}}</ref> corresponding to Torino Scale 8. The 2013 [[Physics:Chelyabinsk meteor|Chelyabinsk meteor]] had a total kinetic energy prior to impact of about 0.5 megatons, corresponding to Torino Scale 0. Between 2000 and 2013, 26 asteroid impacts with an energy of 1–600 kilotons were detected.<ref>{{cite web|url=http://sentinelmission.org/wp-content/uploads/2014/04/B612_PR_042214.pdf |title=Archived copy |access-date=2014-09-05 |url-status=dead |archive-url=https://web.archive.org/web/20140905214015/http://sentinelmission.org/wp-content/uploads/2014/04/B612_PR_042214.pdf |archive-date=2014-09-05 }}</ref>

The biggest hydrogen bomb ever exploded, the Tsar Bomba, was around 50 megatons.
The [[Earth:1883 eruption of Krakatoa|1883 eruption of Krakatoa]] was the equivalent of roughly 200 megatons.

The comet C/2013 A1, which passed close to [[Astronomy:Mars|Mars]] in 2014, was originally estimated to have a potential impact energy of 5 million to 24 billion megatons, and in March 2013 was estimated to have a Mars impact probability of ~1:1250, corresponding to the Martian equivalent of Torino Scale 6.<ref name="Elenin0303">{{cite web|date=3 March 2013|title=Close approach to Mars. Up-to-date analysis|publisher=SpaceObs.org blog (ISON-NM)|first=Leonid|last=Elenin|url=http://spaceobs.org/en/2013/03/03/probability-of-collision-with-mars/|access-date=2013-03-03|archive-date=2013-03-07|archive-url=https://web.archive.org/web/20130307081417/http://spaceobs.org/en/2013/03/03/probability-of-collision-with-mars/|url-status=dead}}</ref> The impact probability was reduced to ~1:120000 in April 2013, corresponding to Torino Scale 1 or 2.<ref>{{cite web|url=http://www.jpl.nasa.gov/news/news.php?release=2013-081|title=News - Comet to Make Close Flyby of Red Planet in October 2014|work=NASA/JPL|access-date=2013-06-05|archive-date=2013-03-08|archive-url=https://web.archive.org/web/20130308140413/http://www.jpl.nasa.gov/news/news.php?release=2013-081|url-status=live}}</ref>

==Objects with non-zero Torino ratings==
[[File:Apophis ellipse.svg|thumb|Diagram showing why as the uncertainty region gets smaller the probability of impact can increase and then suddenly drop to 0.]]<!-- This section is linked from [[Unsolved:Apep|Apep]] -->

===Currently non-zero===

<!-- Leave this section for future non-zero level objects (which quite commonly appear on the Risk List) "* none" when blanking section-->
* none

'''Last updated: '''{{REVISIONYEAR}}-{{REVISIONMONTH}}-{{REVISIONDAY2}}

===Downgraded to zero===
This is a partial list of near-Earth asteroids that have been listed with a Torino Scale rating of 1+ and been lowered to 0 or been removed from the [[Astronomy:Sentry (monitoring system)|Sentry Risk Table]] altogether. Most objects that reach a Torino Scale of 1 have a short observation arc of less than 2 weeks and are quickly removed as the observation arc gets longer and more accurate.

* '''2023'''{{Anchor|2023}}
** {{mp|2023 JE|5}} (diameter ~34 meters) with a 4.7 day observation arc showed a 1 in 480 chance of impact on 4 October 2071.<ref>{{Cite web |url=https://cneos.jpl.nasa.gov/sentry/details.html#?des=2023%20JE5 |title=Sentry: 2023 JE5 |access-date=2023-05-18 |archive-date=2013-05-11 |archive-url=https://web.archive.org/web/20130511010048/http://neo.jpl.nasa.gov/risk/a99942.html#?des=2023%20JE5 |url-status=live }}</ref> The nominal distance from Earth on 4 October 2071 was {{Convert|0.66|AU|e6km|abbr=unit|lk=off}} with a 3-sigma uncertainty region of about ±90 million km,<ref name=Horizons2023JE5>{{cite web |title=JPL Horizons: 2023 JE5 geocentric distance and uncertainty on 4 October 2071 |url=https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272023+JE5%27&START_TIME=%272071-10-04%2020:24%27&STOP_TIME=%272071-10-05%27&STEP_SIZE=%272%20day%27&QUANTITIES=%2720,39%27 |archive-url=https://web.archive.org/web/20230518192929/https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272023+JE5%27&START_TIME=%272071-10-04%2020:24%27&STOP_TIME=%272071-10-05%27&STEP_SIZE=%272%20day%27&QUANTITIES=%2720,39%27 |archive-date=2023-05-18 |url-status=live}}</ref> which placed the impact scenario just outside of the 3-sigma range. With a 6.6-day observation arc the asteroid was dropped to Torino Scale 0 with only a 1 in 3000 chance of impact on 4 October 2071.
** {{mpl|2023 GQ|2}} (diameter ~400 meters) with a 6.7 day observation arc showed a 1 in 24000 chance of impact on 16 November 2028.<ref>{{Cite web |url=https://cneos.jpl.nasa.gov/sentry/details.html#?des=2023%20GQ2 |title=Sentry: 2023 GQ2 |access-date=2023-04-19 |archive-date=2013-05-11 |archive-url=https://web.archive.org/web/20130511010048/http://neo.jpl.nasa.gov/risk/a99942.html#?des=2023%20GQ2 |url-status=live }}</ref> The nominal distance from Earth on 16 November 2028 is now known to be {{Convert|0.0102|AU|e6km|abbr=unit|lk=off}} with a 3-sigma uncertainty region of about ±5 thousand km.<ref name=Horizons2023GQ2>{{cite web
  |title=JPL Horizons: 2023 GQ2 geocentric distance and uncertainty on 16 November 2028
  |url=https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272023+GQ2%27&START_TIME=%272028-11-16%2000:58%27&STOP_TIME=%272028-11-17%27&STEP_SIZE=%272%20day%27&QUANTITIES=%2720,39%27
  |access-date=2023-04-19
  |archive-date=2023-04-20
  |archive-url=https://web.archive.org/web/20230420144523/https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272023+GQ2%27&START_TIME=%272028-11-16%2000:58%27&STOP_TIME=%272028-11-17%27&STEP_SIZE=%272%20day%27&QUANTITIES=%2720,39%27
  |url-status=live
  }}</ref> It was removed from the risk table on 1 May 2023.
**{{mpl|2023 DZ|2}} (diameter ~56 meters) with a 63 day observation arc showed a 1 in 430 chance of impact on 27 March 2026.<ref>[https://archive.today/20230318154854/https://cneos.jpl.nasa.gov/sentry/details.html%23?des=2023%20DZ2 Archive Sentry: 2023 DZ2]</ref> The nominal distance from Earth on 27 March 2026 is now known to be {{Convert|0.0303|AU|e6km|abbr=unit|lk=off}} with a 3-sigma uncertainty region of about ± 1 million km.<ref name=Horizons2023DZ2>{{cite web
  |title=JPL Horizons: 2023 DZ2 geocentric distance and uncertainty on 27 March 2026
  |publisher=JPL Horizons
  |url=https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272023+DZ2%27&START_TIME=%272026-03-27%2014:53%27&STOP_TIME=%272026-03-28%27&STEP_SIZE=%272%20day%27&QUANTITIES=%2720,39%27
  |archive-url=https://web.archive.org/web/20230317184503/https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272023+DZ2%27&START_TIME=%272026-03-27%2014:53%27&STOP_TIME=%272026-03-28%27&STEP_SIZE=%272%20day%27&QUANTITIES=%2720,39%27
  |archive-date=2023-03-17
  |url-status=live
  |accessdate=2023-03-21}}</ref>
**{{mpl|2023 DW}} (diameter ~48 meters) with a 17.7 day observation arc showed a 1 in 360 chance of impact on 14 February 2046.<ref>[https://archive.today/20230316171038/https://cneos.jpl.nasa.gov/sentry/details.html%23?des=2023%20DW Sentry: 2023 DW]</ref> The nominal distance from Earth on 14 February 2046 is now known to be about {{Convert|0.03|AU|e6km|abbr=unit|lk=off}} with a 3-sigma uncertainty region of about ±3 million km.<ref name=Horizons2023DW>{{cite web
  |title=JPL Horizons: 2023 DW geocentric distance and uncertainty on 14 February 2046
  |publisher=JPL Horizons
  |url=https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272023+DW%27&START_TIME=%272046-02-14%2021:36%27&STOP_TIME=%272046-02-15%27&STEP_SIZE=%272%20day%27&QUANTITIES=%2720,39%27
  |archive-url=https://web.archive.org/web/20230304160813/https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272023+DW%27&START_TIME=%272046-02-14%2021:36%27&STOP_TIME=%272046-02-15%27&STEP_SIZE=%272%20day%27&QUANTITIES=%2720,39%27
  |archive-date=2023-03-04
  |url-status=live
  |accessdate=2023-03-21
  }} Risk Corridor Calculations: [https://twitter.com/Piero_Sicoli/status/1631229473570914304 Piero_Sicoli] {{Webarchive|url=https://web.archive.org/web/20230310025553/https://twitter.com/Piero_Sicoli/status/1631229473570914304 |date=2023-03-10 }} and [https://twitter.com/StevearenoBR/status/1631886371823534080 StevearenoBR] {{Webarchive|url=https://web.archive.org/web/20230305181629/https://twitter.com/StevearenoBR/status/1631886371823534080 |date=2023-03-05 }}</ref> It was lowered to Torino scale 0 on 16 March 2023.
**{{mp|2023 AJ|1}} (diameter ~280 meters) with a 15.2 day observation arc showed a cumulative 1 in 21,000 chance of impact on 10 January 2096.<ref>[https://archive.today/20230201094029/https://cneos.jpl.nasa.gov/sentry/details.html%23?des=2023%20AJ1 Archive Sentry: 2023 AJ1]</ref> The nominal distance from Earth on 10 January 2096 was {{Convert|1.2|AU|e6km|abbr=unit|lk=off}} with a 3-sigma uncertainty region of about ±230 million km.<ref name=Horizons2023AJ1>{{cite web
  |title=JPL Horizons: 2023 AJ1 geocentric distance and uncertainty on 10 January 2096
  |publisher=JPL Horizons
  |url=https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272023+AJ1%27&START_TIME=%272096-01-10%27&STOP_TIME=%272096-01-11%27&STEP_SIZE=%272%20day%27&QUANTITIES=%2720,39%27
  |accessdate=2023-01-26
  |archive-date=2023-01-27
  |archive-url=https://web.archive.org/web/20230127062319/https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272023+AJ1%27&START_TIME=%272096-01-10%27&STOP_TIME=%272096-01-11%27&STEP_SIZE=%272%20day%27&QUANTITIES=%2720,39%27
  |url-status=live
  }}</ref> It was removed from the risk table on 8 February 2023.
**{{mp|2023 TL|4}} (diameter ~300 meters) with an observation arc of 38 days showed a 1 in 29000 chance of impact on 10 October 2119.<ref>{{Cite web |url=https://cneos.jpl.nasa.gov/sentry/details.html#?des=2023%20TL4 |title=Sentry: 2023 TL4 |access-date=2023-12-03 |archive-date=2013-05-11 |archive-url=https://web.archive.org/web/20130511010048/http://neo.jpl.nasa.gov/risk/a99942.html#?des=2023%20TL4 |url-status=live }}</ref><ref>{{Cite web |title=ESA Risk List |url=https://neo.ssa.esa.int/risk-list |access-date=2023-11-04 |website=NEO |language=en-GB |archive-date=2023-03-05 |archive-url=https://web.archive.org/web/20230305210103/https://neo.ssa.esa.int/risk-list |url-status=live }}</ref> The nominal distance from Earth on 10 October 2119 is {{Convert|1.4|AU|e6km|abbr=unit|lk=off}} with a 3-sigma uncertainty region of more than a billion km that wraps around the asteroids orbit.<ref name=Horizons2023TL4>{{cite web
  |title=JPL Horizons: 2023 TL4 geocentric distance and uncertainty on 10 October 2119
  |url=https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272023+TL4%27&START_TIME=%272119-10-10%27&STOP_TIME=%272119-10-11%27&STEP_SIZE=%272%20day%27&QUANTITIES=%2720,39%27
  |access-date=2023-12-03
  |archive-date=2023-12-04
  |archive-url=https://web.archive.org/web/20231204142430/https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272023+TL4%27&START_TIME=%272119-10-10%27&STOP_TIME=%272119-10-11%27&STEP_SIZE=%272%20day%27&QUANTITIES=%2720,39%27
  |url-status=live
  }}</ref> So the asteroid is not expected to be near Earth on that date. It was removed from the risk table on 7 December 2023.
* '''2022'''
**{{mpl|2022 UE|28}} (diameter ~170 meters) with a 25 day observation arc showed a 1 in 2,000 chance of impact on 2 April 2064.<ref>[https://archive.today/20221112201640/https://cneos.jpl.nasa.gov/sentry/details.html%23?des=2022%20UE28 Archive Sentry: 2022 UE28]</ref> With a 35-day observation arc, the odds were reduced to 1:150,000. The nominal distance from Earth on 2 April 2064 is now known to be {{Convert|0.06|au|e6km|abbr=unit|lk=off}} with a 3-sigma uncertainty region of about ±8 million km.<ref name=Horizons2022UE28>{{cite web
  |title=JPL Horizons: 2022 UE28 geocentric distance and uncertainty on 2 April 2064
  |publisher=JPL Horizons
  |url=https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272022+UE28%27&START_TIME=%272064-04-02%2012:43%27&STOP_TIME=%272064-04-03%27&STEP_SIZE=%272%20day%27&QUANTITIES=%2720,39%27
  |accessdate=2022-11-23
  |archive-date=2022-11-16
  |archive-url=https://web.archive.org/web/20221116195617/https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272022+UE28%27&START_TIME=%272064-04-02%2012:43%27&STOP_TIME=%272064-04-03%27&STEP_SIZE=%272%20day%27&QUANTITIES=%2720,39%27
  |url-status=live
  }} [https://neo.ssa.esa.int/search-for-asteroids?tab=closeapp&des=2022UE28 (ESA CA: 2022UE28)] {{Webarchive|url=https://web.archive.org/web/20221107080512/https://neo.ssa.esa.int/search-for-asteroids?tab=closeapp&des=2022UE28 |date=2022-11-07 }}</ref>
**{{mpl|2022 QX|4}} (diameter ~40 meters) with a 8 day observation arc showed a 1-in-109 chance of impact on 4 September 2068.<ref>[https://web.archive.org/web/20220904080653/https://neo.ssa.esa.int/risk-list Archive of ESA Risk List]</ref> The nominal distance from Earth on 4 September 2068 is now known to be {{Convert|0.047|AU|e6km|abbr=unit|lk=off}} with an uncertainty region of ±32 thousand km.<ref name=Horizons2022QX4>{{cite web
  |title=JPL Horizons: 2022 QX4 geocentric distance and uncertainty on 4 September 2068
  |publisher=JPL Horizons
  |url=https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272022+QX4%27&START_TIME=%272068-09-04%27&STOP_TIME=%272068-09-05%27&STEP_SIZE=%272%20day%27&QUANTITIES=%2720,39%27
  |accessdate=2022-09-11
  |archive-date=2022-09-05
  |archive-url=https://web.archive.org/web/20220905193726/https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272022+QX4%27&START_TIME=%272068-09-04%27&STOP_TIME=%272068-09-05%27&STEP_SIZE=%272%20day%27&QUANTITIES=%2720%2C39%27
  |url-status=live
  }}</ref>
** {{mpl|2022 BX|1}} (diameter ~160 meters) with a 22 day observation arc showed a 1 in 7,700 chance of impact on 11 July 2061.<ref>{{Cite web |url=https://cneos.jpl.nasa.gov/sentry/details.html%23?des=2022%20BX1 |title=Sentry Archive: 2022 BX1 |access-date=2022-01-29 |archive-date=2022-01-29 |archive-url=https://archive.today/20220129200548/https://cneos.jpl.nasa.gov/sentry/details.html%23?des=2022%20BX1 |url-status=live }}</ref> It was lowered to Torino Scale 0 with a 24 day observation arc. The nominal distance from Earth on 11 July 2061 is {{Convert|0.14|AU|e6km|abbr=unit|lk=off}} with an uncertainty region of ±600 thousand km.<ref name=Horizons2022BX1>{{cite web
  |title=JPL Horizons: 2022 BX1 geocentric distance and uncertainty on 11 July 2061
  |publisher=JPL Horizons
  |url=https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272022+BX1%27&START_TIME=%272061-07-11+21:22%27&STOP_TIME=%272061-07-12%27&STEP_SIZE=%271+day%27&QUANTITIES=%2720%2C39%27
  |accessdate=2022-01-29
  |archive-date=2022-01-29
  |archive-url=https://web.archive.org/web/20220129213837/https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272022+BX1%27&START_TIME=%272061-07-11+21%3A22%27&STOP_TIME=%272061-07-12%27&STEP_SIZE=%271+day%27&QUANTITIES=%2720%2C39%27
  |url-status=live
  }}</ref>
** {{mpl|2022 AE|1}} (diameter ~70 meters) with a 3-8 day observation arc showed about a 1 in 2,000 chance of impact (18 months later) on 4 July 2023.<ref name=ESA20220111>{{cite web| url = https://neo.ssa.esa.int/risk-list| title = Archive esa Risk List with 2022 AE1| archive-url = https://web.archive.org/web/20220111175710/https://neo.ssa.esa.int/risk-list| archive-date = 2022-01-11}}</ref> The nominal distance from Earth on 4 July 2023 was estimated as small as {{Convert|0.024|AU|e6km|abbr=unit|lk=off}} with an uncertainty region of ±38 million km. It was lowered to Torino Scale 0 on 20 January 2022 with a 16 day observation arc and a nominal approach of 7.9 million km.
* '''2021'''
** {{mpl|2021 TP|21}} (diameter ~300 meters) with a 18.9 day observation arc showed a 1 in 56,000 chance of impact on 27 March 2081.<ref name=ESA20211031>{{cite web| url = https://neo.ssa.esa.int/risk-list| title = Archive esa Risk List with 2021 TP21| archive-url = https://web.archive.org/web/20211031094029/https://neo.ssa.esa.int/risk-list| archive-date = 2021-10-31}}</ref> The nominal distance from Earth on 27 March 2081 was estimated at {{Convert|1.4|AU|e6km|abbr=unit|lk=off}} with an uncertainty region of ±870 million km.<ref name=Horizons2021TP21>{{cite web  |title=JPL Horizons Archive: 2021 TP21 geocentric distance and uncertainty on 27 March 2081
  |publisher=JPL Horizons
  |url=https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272021+TP21%27&START_TIME=%272081-03-26%27&STOP_TIME=%272081-03-28%27&STEP_SIZE=%271+day%27&QUANTITIES=%2720%2C39%27 |archive-url=https://web.archive.org/web/20211031005214/https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272021+TP21%27&START_TIME=%272081-03-26%27&STOP_TIME=%272081-03-28%27&STEP_SIZE=%271+day%27&QUANTITIES=%2720%2C39%27
 |archive-date=2021-10-31
 }}</ref> It was removed from the Sentry risk list on 4 November 2021 with a 57 day observation arc and a nominal approach of 2.5 AU with an uncertainty region of ±18 million km.
** {{mpl|2021 TA|8}} (diameter ~200 meters) with a 7.6 day observation arc showed a 1 in 6,700 chance of impact on 3 May 2034.<ref name=ESA20211012>{{cite web| url = https://neo.ssa.esa.int/risk-list| title = Archive esa Risk List with 2021 TA8| archive-url = https://web.archive.org/web/20211012143624/https://neo.ssa.esa.int/risk-list| archive-date = 2021-10-12}}</ref> With a 7 day arc, the nominal distance from Earth on 3 May 2034 was {{Convert|0.03|AU|e6km|abbr=unit|lk=off}} with an uncertainty region of ±20 million km.<ref name=Horizons2021TA8>{{cite web  |title=Archive JPL Horizons: 2021 TA8 geocentric distance and uncertainty on 3 May 2034
  |url=https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272021+TA8%27&START_TIME=%272034-05-02%27&STOP_TIME=%272034-05-04%27&STEP_SIZE=%271+day%27&QUANTITIES=%2720%2C39%27
  |date=2021-10-12 |archive-url = https://web.archive.org/web/20211012075513/https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272021+TA8%27&START_TIME=%272034-05-02%27&STOP_TIME=%272034-05-04%27&STEP_SIZE=%271+day%27&QUANTITIES=%2720%2C39%27|archive-date = 2021-10-12}}</ref> It was removed from the ESA and Sentry Risk Table on 12 October 2021 when precovery images from 2010, 2015 and 2018 were located in the DECam and [[Astronomy:Pan-STARRS|Pan-STARRS]] archives.
* '''2020'''{{Anchor|2020}}
** {{mpl|2020 XR}} (diameter ~390 meters) with a 5 day observation arc showed a 1 in 11,000 chance of impact on 1 December 2028<ref>{{cite web| url = http://www.hohmanntransfer.com/mn/20/20345_1210.htm#2020XR| title = hohmanntransfer: 2020 XR (10 Dec 2020)| access-date = 12 December 2020| archive-date = 28 February 2021| archive-url = https://web.archive.org/web/20210228012834/http://www.hohmanntransfer.com/mn/20/20345_1210.htm#2020XR| url-status = live}}</ref> and a nominal distance from Earth on 1 December 2028 of {{Convert|0.16|AU|e6km LD|abbr=unit|lk=off}} with an uncertainty region of ±304 million km. The 8 day observation arc showed a 1 in 26,000 chance of impact on 1 December 2028 and a nominal distance from Earth on 1 December 2028 of {{Convert|1|AU|e6km LD|abbr=unit|lk=off}}. On 13 December 2020 precovery observations from 2013, 2016, and mid-2020 extended the observation arc from 8 days to 7.8 years allowing the asteroid to be removed from the Sentry Risk Table.
** {{mpl|2020 NK|1}} (diameter ~600 meters) initially showed, with a 7.6 day observation arc, a 1 in 83,000 chance of impact on 3 August 2093.<ref name="K20NK1">{{cite web| url = https://cneos.jpl.nasa.gov/sentry/details.html#?des=2020%20NK1| title = Sentry: 2020 NK1| access-date = 2020-07-22| archive-date = 2013-05-11| archive-url = https://web.archive.org/web/20130511010048/http://neo.jpl.nasa.gov/risk/a99942.html#?des=2020%20NK1| url-status = live}}</ref> With a 11.2 day observation arc, the odds decreased to 1 in 7.1 million. However, the odds of an impact on 4 August 2104 increased to 1 in 45,000.<ref name="K20NK1"/> With a 13.2 day observation arc, the 2104 impact was ruled out, but a 4 August 2101 impact became more probable, with the odds increasing to 1 in 36,000.<ref name="K20NK1"/> The nominal distance from Earth on 4 August 2101 is {{Convert|0.87|AU|e6km|abbr=unit|lk=off}}. It was removed from the sentry risk table entirely on July 31 with a 15.6 day observation arc.
** {{mpl|2020 DR|2}} (diameter ~590 meters) with a 15-day observation showed a 1 in 290,000 chance of impact on 10 September 2074 and showed a 1 in 77,000 chance of impact on 9 September 2081.<ref>[https://cneos.jpl.nasa.gov/sentry/details.html#?des=2020%20DR2 Sentry: Earth Impact Monitoring 2020 DR2 -- Earth Impact Risk Summary]  Also See [https://archive.today/20200229100328/https://cneos.jpl.nasa.gov/sentry/details.html%23?des=2020%20DR2  Archive.is]</ref> Cumulatively, this gave the asteroid a 1 in 59,000 chance of impact in the next century. The asteroid was downgraded to 0 after its arc was extended to 16 days with a 1 in 500,000 cumulative chance of impact. It was removed from the sentry risk table entirely on 11 March 2020.
** {{mpl|2020 BW|14}} (diameter ~700 meters) with a 13-day observation arc showed a 1 in 180,000 chance of impact on 14 October 2046.<ref>{{cite web |url = https://cneos.jpl.nasa.gov/sentry/details.html%23?des=2020%20BW14 |title = Archive.is of Sentry: 2020 BW14 |archive-url=https://archive.today/20200207192115/https://cneos.jpl.nasa.gov/sentry/details.html%23?des=2020%20BW14 |archive-date=7 February 2020 |url-status=dead}}</ref> But the nominal solution had the asteroid {{Convert|0.7|AU|e6km|abbr=unit}} from Earth on 14 October 2046. It was removed from the Sentry monitoring list on 10 February 2020 with 19 precovery images from January to April 2016.<ref>{{cite web| url = https://minorplanetcenter.net/mpec/K20/K20CC5.html| title = MPEC 2020-C125 : 2020 BW14| access-date = 2020-02-10| archive-date = 2021-03-08| archive-url = https://web.archive.org/web/20210308172653/https://minorplanetcenter.net/mpec/K20/K20CC5.html| url-status = live}}</ref>
* '''2019'''
** No asteroids reached Torino scale 1 in 2019.
* '''2018'''{{Anchor|2018}}
** {{mpl|2018 LB|1}} was removed from the Sentry monitoring list on 14 June 2018<ref>{{cite web |url=https://cneos.jpl.nasa.gov/sentry/removed.html |title=Sentry: Earth Impact Monitoring Removed Objects |access-date=2018-08-26 |archive-date=2017-10-17 |archive-url=https://web.archive.org/web/20171017180942/https://cneos.jpl.nasa.gov/sentry/removed.html |url-status=live }}</ref> after having been on the Risk List with a Torino Scale of Level 1.
** {{mpl|2018 GG|2}} (diameter ~480 meters) with a 7-day observation arc showed a 1 in 270,000 chance of impact on 5 April 2111 using the 17 April 2018 orbit solution.<ref name=risk2018GG2>{{cite web|url=https://cneos.jpl.nasa.gov/sentry/details.html#?des=2018%20GG2 |title=2018 GG2 Impact Risk |access-date=2018-04-17 |work=Near Earth Object Program |publisher=NASA |archive-url=https://web.archive.org/web/20180417194747/https://cneos.jpl.nasa.gov/sentry/details.html#?des=2018%20GG2 |archive-date=2018-04-17 |url-status=dead}}</ref> Later on the same day it was removed from the Sentry Risk Table as a result of precovery images dating back to 24 September 2017 extending the observation arc to 205 days.
** {{mpl|2017 XO|2}} was listed on the JPL Near Earth Object Risk List with a Torino Scale of Level 1 as of 20 January 2018. With a 40-day [[Astronomy:Observation arc|observation arc]], it had an estimated 1 in 3000 chance of impacting Earth on 28 April 2057.<ref>{{cite web | url=https://cneos.jpl.nasa.gov/sentry/details.html#?des=2017%20XO2 | title=Sentry: Earth Impact Monitoring | access-date=2018-01-20 | archive-date=2013-05-11 | archive-url=https://web.archive.org/web/20130511010048/http://neo.jpl.nasa.gov/risk/a99942.html#?des=2017%20XO2 | url-status=live }}</ref> The asteroid is estimated to have a diameter of about {{convert|110|m|sp=us}}. The nominal 2057 Earth approach distance was estimated at {{convert|0.001|au|km mi|sigfig=1|abbr=on}} with a 3-sigma uncertainty of ±52 million km. On 27 January 2018 Pan-STARRS precovery images from November and December 2011 were announced, and {{mp|2017 XO|2}} was removed from the Sentry Risk Table.
** {{mpl|2017 YZ|1}} was listed on the JPL Near Earth Object Risk List and NEODyS Risk List with a Torino Scale of Level 1 on 5 January 2018. With a 15-day observation arc, it had an estimated 1 in 21000 chance of impacting Earth on 30 June 2047. The asteroid is estimated to have a diameter of {{convert|260|m|sp=us}}, and would impact Earth at a relative speed of {{convert|18|km/s|mph|sigfig=2|abbr=on}}. By 9 January 2018 the geocentric 30 June 2047 uncertainty region had shrunk to ±50 million km. After calculations based on a 20-day observation arc were made, chances of impact on 30 June 2047 dropped to 1 in 670000, and {{nowrap|2017 YZ<sub>1</sub>}} was downgraded to Level 0.
* '''2017'''
** {{mpl|2017 CH|1}} was listed on the NEODyS Risk List with a Torino Scale of Level 1 on 8 February 2017.<ref name=risk2017CH1>{{cite web|url=https://newton.spacedys.com/neodys/index.php?pc=1.1.2&n=2017CH1 |title=2017 CH1 Impactor Table |access-date=2017-02-08 |archive-url=https://archive.today/20170208224251/http://newton.dm.unipi.it/neodys/index.php?pc=1.1.2&n=2017CH1 |archive-date=2017-02-08 |url-status=dead }}<!-- Do not update URL to the current newton.spacedys.com; it does not have the impactor page for this object; the archive is sufficient --></ref> It is estimated be 900 meters in diameter with a 1 in 500000 chance of impact on 4 June 2095.<ref name=risk2017CH1/> Such an impact could create a crater 10&nbsp;km in diameter.<ref>{{cite web| url = http://impact.ese.ic.ac.uk/cgi-bin/crater.cgi?dist=100&diam=900&pdens=1500&pdens_select=0&vel=21.24&theta=45&tdens=2750&tdens_select=0| title = 2017 CH1 Earth Impact| access-date = 2017-02-08| archive-date = 2017-02-11| archive-url = https://web.archive.org/web/20170211080417/http://impact.ese.ic.ac.uk/cgi-bin/crater.cgi?dist=100&diam=900&pdens=1500&pdens_select=0&vel=21.24&theta=45&tdens=2750&tdens_select=0| url-status = live}}</ref> Follow-up observations on February 10 eliminated the chances of impact on every date except for 4 June 2044, with a 4.59E-10 chance of impact on that date, or less than a 1 in 2 billion chance of impact. It was removed from the Sentry Risk Table on 15 February 2017.
** {{mpl|2017 BL|30}} was listed on the JPL Near Earth Object Risk List and NEODyS Risk List with a Torino Scale of Level 1 on 3 February 2017.<ref name=risk2017BL30>{{cite web|url=http://neo.jpl.nasa.gov/risk/2017bl30.html |title=2017 BL30 Impact Risk |access-date=2017-02-03 |work=Near Earth Object Program |publisher=NASA |archive-url=https://archive.today/20170203231237/http://neo.jpl.nasa.gov/risk/2017bl30.html |archive-date=2017-02-03 |url-status=dead }}</ref> With a 5-day [[Astronomy:Observation arc|observation arc]], it had an estimated 1 in 1610 chance of impacting Earth on 3 August 2029.<ref name=risk2017BL30/> With a 6-day observation arc, the odds were 1 in 1270.<ref name=risk2017BL30/> With a 7-day observation arc, the odds were 1 in 909.<ref name=risk2017BL30/> With a 10-day observation arc, the odds were 1 in 826.<ref name=risk2017BL30/> The asteroid is estimated to have a diameter of {{convert|70|m|sp=us}}, and would impact Earth at a relative speed of {{convert|13|km/s|mph|sigfig=2|abbr=on}}.<ref name=risk2017BL30/> The value decreased to 0 with further observations on February 11, with a cumulative impact chance of 1 in 4258.
** {{mpl|2017 AM|4}} was listed on the JPL Near Earth Object Risk List and NEODyS Risk List with a Torino Scale of Level 1 on 19 January 2017.<ref name=risk2017AM4>{{cite web|url=http://neo.jpl.nasa.gov/risk/2017am4.html |title=2017 AM4 Impact Risk |access-date=2017-01-19 |work=Near Earth Object Program |publisher=NASA |archive-url=https://web.archive.org/web/20170119182230/http://neo.jpl.nasa.gov/risk/2017am4.html |archive-date=2017-01-19 |url-status=dead }}</ref> With a 14-day [[Astronomy:Observation arc|observation arc]], it had an estimated 1 in 59,000 chance of impacting Earth on 1 August 2024.<ref name=risk2017AM4/> The asteroid is estimated to have a diameter of {{convert|500|m|sp=us}}, and would impact Earth at a relative speed of {{convert|33|km/s|mph|sigfig=2|abbr=on}}.<ref name=risk2017AM4/> With a 16-day observation arc, the odds of impact were reduced to 1 in a million. It was removed from the Sentry Risk Table on 23 January 2017 with a 19-day observation arc.
* '''2016'''
** {{mpl|2016 XP|23}} was listed on the JPL Near Earth Object Risk List with a Torino Scale of Level 1 on 25 December 2016,<ref name=risk2016XP23>{{cite web|url=http://neo.jpl.nasa.gov/risk/2016xp23.html |title=2016 XP23 Impact Risk |access-date=2016-12-25 |work=Near Earth Object Program |publisher=NASA |archive-url=https://web.archive.org/web/20161225174821/http://neo.jpl.nasa.gov/risk/2016xp23.html |archive-date=2016-12-25 |url-status=dead }}</ref> while the NEODyS Risk List has it at a lower impact probability, sufficient to classify it as Torino Scale Level 0. With a 15-day observation arc, it was listed with an estimated 1 in 105,000 chance of impacting Earth on 1 November 2110.<ref name=risk2016XP23/> The asteroid is estimated to have a diameter of {{convert|360|m|sp=us}}, and would have impacted Earth at a relative speed of {{convert|27|km/s|mph|sigfig=2|abbr=on}}.<ref name=risk2016XP23/> It was removed from the Sentry Risk Table on 7 January 2017 with a 29-day observation arc.
** {{mpl|2016 WJ|1}} was listed on the JPL Near Earth Object Risk List with a Torino Scale of Level 1 on 25 November 2016,<ref name=risk2016WJ1>{{cite web|url=http://neo.jpl.nasa.gov/risk/2016wj1.html |title=2016 WJ1 Impact Risk |access-date=2016-11-25 |work=Near Earth Object Program |publisher=NASA |url-status=dead |archive-url=https://archive.today/20161130122614/http://neo.jpl.nasa.gov/risk/2016wj1.html |archive-date=2016-11-30 }}</ref> while the NEODyS Risk List has it at a lower impact probability, sufficient to classify it as Torino Scale Level 0. With a 10-day [[Astronomy:Observation arc|observation arc]], it had an estimated 1 in 8000 chance of impacting Earth on 12 June 2065.<ref name=risk2016WJ1/> It was discovered on 19 November 2016 by Mt. Lemmon Survey.<ref name=mpc2016WJ1>{{cite web |url=http://www.minorplanetcenter.net/mpec/K16/K16W38.html |title=MPEC 2016-W38 : 2016 WJ1 |access-date=2016-11-25 |work=Minor Planet Electronic Circular |publisher=MPC |archive-date=2016-11-25 |archive-url=https://web.archive.org/web/20161125112835/http://www.minorplanetcenter.net/mpec/K16/K16W38.html |url-status=live }}</ref> The asteroid is estimated to have a diameter of {{convert|180|m|sp=us}}, and would have impacted Earth at a relative speed of {{convert|18.61|km/s|mph|sigfig=2|abbr=on}}.<ref name=risk2016WJ1/> It was removed from the Sentry Risk Table on 2 December 2016, when prediscovery images by Pan-STARRS from October 2016 and precovery images taken from Mauna Kea in July 2003 where located and included in the impact calculations.
** {{mpl|2016 EU|85}} was rated at level 1 by [[Astronomy:NEODyS|NEODyS]] on 25 March 2016, but subsequently lowered to zero thanks to prediscovery observations by the [[Astronomy:Pan-STARRS|Pan-STARRS]] survey. The asteroid is estimated to have a diameter of about {{convert|440|m|sp=us}}.
** {{mpl|2016 BE}} was rated at level 1 for a day on 25 January 2016 by the [[Astronomy:NEODyS|NEODyS]] system, and downgraded to level 0 the following day. On the [[Astronomy:Sentry (monitoring system)|Sentry]] system it never crossed the threshold between the two levels, due to a lower computed impact probability.
* '''2015'''{{Anchor|2015}}
** {{mpl|2015 PU|228}} was listed on [[Astronomy:NEODyS|NEODyS]] with a Torino Scale of Level 1 on 23 August 2015.<ref name=NeoDyS2015PU228>{{cite web|url=https://newton.spacedys.com/neodys/index.php?pc=1.1.2&n=2015PU228 |title=2015 PU228 Impact Table |access-date=2015-08-24 |work=NEODyS |url-status=dead |archive-url=https://web.archive.org/web/20150824084812/http://newton.dm.unipi.it/neodys/index.php?pc=1.1.2&n=2015PU228 |archive-date=August 24, 2015 }}<!-- Do not update URL to the current newton.spacedys.com; it does not have the impactor page for this object; the archive is sufficient --></ref> [[Astronomy:Sentry (monitoring system)|Sentry]] also listed it with a Torino Scale of Level 1 on 24 August 2015.<ref name=risk2015PU228>{{cite web|url=http://neo.jpl.nasa.gov/risk/2015pu228.html |title=2015 PU228 Impact Risk |access-date=2015-08-24 |work=Near Earth Object Program |publisher=NASA |url-status=dead |archive-url=https://web.archive.org/web/20150828141239/http://neo.jpl.nasa.gov/risk/2015pu228.html |archive-date=August 28, 2015 }}</ref> With a 10-day [[Astronomy:Observation arc|observation arc]], it had an estimated 1 in 84,000 chance of impacting Earth on 15 January 2081.<ref name=NeoDyS2015PU228/> It was downgraded to level 0 on 8 September 2015. It was discovered on 13 August 2015 by the [[Astronomy:Space Surveillance Telescope|Space Surveillance Telescope]].<ref name=mpc2015PU228>{{cite web |url=http://www.minorplanetcenter.net/mpec/K15/K15P73.html |title=MPEC 2015-P73 : 2015 PU228 |access-date=2015-08-24 |work=Minor Planet Electronic Circular |publisher=MPC |archive-date=2015-09-04 |archive-url=https://web.archive.org/web/20150904024112/http://www.minorplanetcenter.net/mpec/K15/K15P73.html |url-status=live }}</ref> The asteroid is estimated to have a diameter of {{convert|340|m|sp=us}}.
** {{mpl|2015 NK|13}} was listed on the JPL Near Earth Object Risk List with a Torino Scale of Level 1 on 22 July 2015 and again on 11 August 2015,<ref name=risk2015NK13>{{cite web|url=http://neo.jpl.nasa.gov/risk/2015nk13.html |title=2015 NK13 Impact Risk |work=Near Earth Object Program |publisher=NASA |url-status=dead |archive-url=https://web.archive.org/web/20150722180200/http://neo.jpl.nasa.gov/risk/2015nk13.html |archive-date=July 22, 2015 }}</ref> while the NEODyS Risk List had it at a slightly lower impact probability, sufficient to classify it as Torino Scale Level 0. In July and August it was downgraded to Level 0 the following day. With a 13-day [[Astronomy:Observation arc|observation arc]], it had an estimated 1 in 36,000 chance of impacting Earth on 5 October 2096.<ref name=risk2015NK13/> It was discovered on 12 July 2015 by [[Astronomy:Pan-STARRS|Pan-STARRS]].<ref name=mpc2015NK13>{{cite web |url=http://www.minorplanetcenter.net/mpec/K15/K15N44.html |title=MPEC 2015-N44 : 2015 NK13 |access-date=2015-07-22 |work=Minor Planet Electronic Circular |publisher=MPC |archive-date=2015-09-04 |archive-url=https://web.archive.org/web/20150904024112/http://www.minorplanetcenter.net/mpec/K15/K15N44.html |url-status=live }}</ref> The asteroid is estimated to have a diameter of {{convert|310|m|sp=us}}, and would impact Earth at a relative speed of {{convert|14.35|km/s|mph|sigfig=2|abbr=on}}.<ref name=risk2015NK13/>
* '''2014'''
** {{mpl|2007 VK|184}} was listed on the Near Earth Object Risk List with a Torino Scale of Level 1<ref name=risk2007VK184>{{cite web|url=http://neo.jpl.nasa.gov/risk/2007vk184.html |title=2007 VK184 Impact Risk |access-date=2014-04-01 |work=Near Earth Object Program |publisher=NASA |url-status=dead |archive-url=https://web.archive.org/web/20140320061435/http://neo.jpl.nasa.gov/risk/2007vk184.html |archive-date=March 20, 2014 }}</ref> from after its discovery in November 2007 until recovered in March 2014. With an observation arc of 60 days, it had about a 1 in 1800 chance of impacting Earth on 3 June 2048; the probability went to effectively zero when the 2014 recovery observations were taken into account. The asteroid is estimated to have a diameter of {{convert|130|m|sp=us}}, and travels through space with a speed of 15.6&nbsp;km/s relative to Earth.
** {{mpl|2014 DA}} with an estimated diameter of 100 meters was rated level 1 on 23 February 2014 with an observation arc of 5 days. It was estimated to have a 1 in 5,560 chance of impact on 2 February 2027.<ref>archive is/Wx0I3</ref> It was lowered to Torino Scale 0 on the next day (24 February 2014).<ref>{{cite web|url=http://neo.jpl.nasa.gov/risk/2014da.html |title=2014 DA Impact Risk |work=Near Earth Object Program |publisher=NASA |url-status=dead |archive-url=https://web.archive.org/web/20140224052603/http://neo.jpl.nasa.gov/risk/2014da.html |archive-date=February 24, 2014 }}</ref>
* '''2013'''
** {{mpl|2013 TV|135}} (a near-Earth asteroid with a 450&nbsp;m diameter) was rated level 1 on 16 October 2013 (with an observation arc of 7.3 days).<ref name="tv135">{{cite web |date=2013-11-02 |title=Observations of small Solar-System bodies (2013 TV135) |publisher=hohmanntransfer |url=http://www.hohmanntransfer.com/mn/13/13289_1016.htm#2013TV135 |access-date=2013-11-02 |archive-date=2013-11-03 |archive-url=https://web.archive.org/web/20131103053616/http://www.hohmanntransfer.com/mn/13/13289_1016.htm#2013TV135 |url-status=dead }}</ref> It was downgraded to 0 on 3 November 2013.<ref name=risk2013TV135>{{cite web|url=http://neo.jpl.nasa.gov/risk/2013tv135.html |title=2013 TV135 Impact Risk |access-date=2013-11-03 |work=Near Earth Object Program |publisher=JPL |url-status=dead |archive-url=https://web.archive.org/web/20131017011711/http://neo.jpl.nasa.gov/risk/2013tv135.html |archive-date=2013-10-17 }}</ref> It was completely removed from the Sentry Risk Table on 8 November 2013 using JPL solution 32 with an observation arc of 27 days.<ref name="removed"/>
* '''2012'''
** {{mpl|(367789) 2011 AG|5}} was rated at Torino scale 1 from February 2011 to December 2012, for an impact on 5 February 2040.<ref name="nasa_2011ag">{{cite web |url=http://neo.jpl.nasa.gov/risk/2011ag5.html |archive-url=https://web.archive.org/web/20110211045837/http://neo.jpl.nasa.gov/risk/2011ag5.html |url-status=dead |archive-date=2011-02-11 |title={{mp|2011 AG|5}} Impact Risk |access-date=2011-02-07 |work=Near Earth Object Program |publisher=NASA}}</ref> It was downgraded thanks to observations collected in October 2012 with telescopes on [[Astronomy:Mauna Kea Observatory|Mauna Kea]], Hawaii.
** {{mpl|2012 MU|2}} was rated at Torino scale 1 on 23 June 2012 with an observation arc of 4 days.<ref name="mu2">{{cite web |date=2012-06-23 |title=Observations of small Solar-System bodies (2012 MU2) |publisher=hohmanntransfer |url=http://www.hohmanntransfer.com/mn/12/12175_0623.htm#2012MU2 |access-date=2013-09-04 |archive-date=2012-08-19 |archive-url=https://web.archive.org/web/20120819155543/http://www.hohmanntransfer.com/mn/12/12175_0623.htm#2012MU2 |url-status=dead }}</ref> With an observation arc of only 6 days it showed a 1 in 7140 chance of impact on 1 June 2015. It was removed from the Sentry Risk Table on June 25.<ref name="removed"/>
** {{mpl|2012 CA|21}} was rated level 1 on 21 February 2012 (with an observation arc of 8.9 days).<ref name="ca21">{{cite web |date=2012-02-21 |title=Observations of small Solar-System bodies (2012 CA21) |publisher=hohmanntransfer |url=http://www.hohmanntransfer.com/mn/12/12052_0221.htm#2012CA21 |access-date=2013-09-04 |archive-date=2015-09-04 |archive-url=https://web.archive.org/web/20150904024112/http://www.hohmanntransfer.com/mn/12/12052_0221.htm#2012CA21 |url-status=dead }}</ref> It was removed from the risk table on 3 March 2012.<ref name="removed"/>
* '''2011'''
** {{mpl|(436724) 2011 UW|158}} was rated level 1 on 4 November 2011 with an observation arc of 9 days.<ref name=UW158>{{cite web|url=http://neo.jpl.nasa.gov/risk/2011uw158.html |title=2011 UW158 Impact Risk |work=Near Earth Object Program |publisher=NASA |url-status=dead |archive-url=https://web.archive.org/web/20111106205050/http://neo.jpl.nasa.gov/risk/2011uw158.html |archive-date=November 6, 2011 }}</ref> There was a 1 in 56,000 chance of impact on 8 July 2079.<ref name=UW158/> It was removed 17 November 2011.<ref name="removed"/>
** {{mpl|(415029) 2011 UL|21}} is an asteroid with a diameter of 2.6&nbsp;km, which was rated level 1 on October 27, 2011 (with an observation arc of 9.6 days.)<ref name="ul21">{{cite web |date=2011-10-27 |title=Observations of small Solar-System bodies (2011 UL21) |publisher=hohmanntransfer |url=http://www.hohmanntransfer.com/mn/11/11300_1027.htm#2011UL21 |access-date=2013-09-04 |archive-date=2014-11-29 |archive-url=https://web.archive.org/web/20141129025147/http://www.hohmanntransfer.com/mn/11/11300_1027.htm#2011UL21 |url-status=dead }}</ref> It was downgraded to 0 a few days later.
** {{mpl|2011 SM|68}} was rated level 1 on 28 September 2011 with an observation arc of 2.6 days and listed virtual impactors in 2016 and 2019.<ref name=sm68>{{cite web|url=http://neo.jpl.nasa.gov/risk/2011sm68.html |title={{mp|2011 SM|68}} Impact Risk |access-date=2011-09-29 |work=Near Earth Object Program |publisher=NASA |url-status=dead |archive-url=https://web.archive.org/web/20110930125627/http://neo.jpl.nasa.gov/risk/2011sm68.html |archive-date=September 30, 2011 }}</ref> But it was quickly downgraded to 0 a few days later and was removed from the risk table on 7 October 2011.<ref name="removed"/>
** {{mpl|2011 BM|45}} was rated level 1 on 13 February 2011 with an observation arc of 13.8 days.<ref name=BM45/> There was a 1 in 24,000 chance of impact on 18 January 2086.<ref name=BM45>{{cite web|url=http://neo.jpl.nasa.gov/risk/2011bm45.html |title={{mp|2011 BM|45}} Impact Risk |access-date=2011-02-25 |work=Near Earth Object Program |publisher=NASA |url-status=dead |archive-url=https://web.archive.org/web/20110216072544/http://neo.jpl.nasa.gov/risk/2011bm45.html |archive-date=February 16, 2011 }}</ref> It was removed from the risk table on 10 March 2011.<ref name="removed"/>
* '''2010'''{{Anchor|2010}}
** {{mpl|2010 XC|25}} was rated level 1 in December 2010, and downgraded to 0 on 2 January 2011.<ref>{{cite web|url=http://neo.jpl.nasa.gov/risk/2010xc25.html |title={{mp|2010 XC|25}} Impact Risk |work=Near Earth Object Program |publisher=NASA |url-status=dead |archive-url=https://web.archive.org/web/20101216031855/http://neo.jpl.nasa.gov/risk/2010xc25.html |archive-date=December 16, 2010 }}<!--not in Wayback Machine--></ref>
** {{mpl|(494999) 2010 JU|39}} was rated level 1 on 18 May 2010 with an observation arc of 7 days.<ref name=JU>{{cite web|url=http://neo.jpl.nasa.gov/risk/2010ju39.html |title=2010 JU39 Impact Risk |work=Near Earth Object Program |publisher=NASA |url-status=dead |archive-url=https://web.archive.org/web/20100522151206/http://neo.jpl.nasa.gov/risk/2010ju39.html |archive-date=May 22, 2010 }}</ref> There was roughly an estimated 1 in 77,000 chance of impact on 26 June 2058.<ref name=JU/> It was removed on 23 May 2010.<ref name="removed"/>
** {{mpl|(308635) 2005 YU|55}} was rated level 1 in February 2010,<ref name=yu55>{{cite web|url=http://neo.jpl.nasa.gov/risk/2005yu55.html |title={{mp|2005 YU|55}} Impact Risk |access-date=2010-02-25 |work=Near Earth Object Program |publisher=NASA |url-status=dead |archive-url=https://web.archive.org/web/20100125013913/http://neo.jpl.nasa.gov/risk/2005yu55.html |archive-date=January 25, 2010 }}</ref> and downgraded to 0 on 9 April 2010. The chance of an actual collision with an asteroid like 2005 YU55 (~400 meters in diameter) is about 1 percent in the next thousand years.<ref name="Melosh2011"/>
* '''2009'''
** {{mpl|(359369) 2009 YG}} was rated level 1 on 28 December 2009 (with an observation arc of 10 days).<ref name="yg">{{cite web |date=2009-12-28 |title=Observations of small Solar-System bodies (2009 YG) |publisher=hohmanntransfer |url=http://www.hohmanntransfer.com/mn/09/09362_1228.htm#2009YG |access-date=2013-09-04 |archive-date=2010-12-18 |archive-url=https://web.archive.org/web/20101218080719/http://hohmanntransfer.com/mn/09/09362_1228.htm#2009YG |url-status=dead }}</ref> It was downgraded to 0 by the end of December.
** {{mpl|2009 WM|1}} was rated level 1 after its discovery on 17 November 2009,<ref>{{cite web|url=http://neo.jpl.nasa.gov/risk/2009wm1.html |title={{mp|2009 WM|1}} Earth Impact Risk |access-date=2009-11-26 |work=Near Earth Object Program |publisher=NASA |url-status=dead |archive-url=https://web.archive.org/web/20091124204629/http://neo.jpl.nasa.gov/risk/2009wm1.html |archive-date=November 24, 2009 }}</ref> and downgraded by the end of November. It was not removed from the risk table until 26 June 2013.<ref name="removed"/>
** {{mpl|2009 KK}} was rated level 1 after its discovery in May 2009 (with a 15-day observation arc),<ref name=KK>{{cite web|url=http://neo.jpl.nasa.gov/risk/2009kk.html |title=2009 KK Impact Risk |work=Near Earth Object Program |publisher=NASA |url-status=dead |archive-url=https://web.archive.org/web/20090604075619/http://neo.jpl.nasa.gov/risk/2009kk.html |archive-date=June 4, 2009 }}</ref> and downgraded to 0 by 11 June 2009. It was removed 17 June 2009.<ref name="removed"/>
* '''2008'''
** {{mpl|(332446) 2008 AF|4}} was rated level 1<ref name=AF4>{{cite web|url=http://neo.jpl.nasa.gov/risk/2008af4.html |title={{mp|2008 AF|4}} Impact Risk |work=Near Earth Object Program |publisher=NASA |url-status=dead |archive-url=https://web.archive.org/web/20080115090715/http://neo.jpl.nasa.gov/risk/2008af4.html |archive-date=January 15, 2008 }}</ref> until 14 February 2008. It was removed from the risk table on 19 December 2009.<ref name="removed"/>
* '''2007'''
** {{mpl|(435159) 2007 LQ|19}} was rated level 1 on 3 July 2007 with an observation arc of 19 days.<ref name=LQ19>{{cite web|url=http://neo.jpl.nasa.gov/risk/2007lq19.html |title=2007 LQ19 Impact Risk |work=Near Earth Object Program |publisher=NASA |url-status=dead |archive-url=https://web.archive.org/web/20070714165021/http://neo.jpl.nasa.gov/risk/2007lq19.html |archive-date=July 14, 2007 }}</ref> The asteroid was estimated to be {{convert|930|m|sp=us}} in diameter and there was a 1 in 556,000 chance of impact on 11 July 2082.<ref name=LQ19/> It was removed from the risk table on 15 July 2007.<ref name="removed"/>
**{{mpl|(481482) 2007 CA|19}} was rated level 1<ref name=CA19>{{cite web|url=http://neo.jpl.nasa.gov/risk/2007ca19.html |title={{mp|2007 CA|19}} Impact Risk |work=Near Earth Object Program |publisher=NASA |url-status=dead |archive-url=https://web.archive.org/web/20070216055152/http://neo.jpl.nasa.gov/risk/2007ca19.html |archive-date=February 16, 2007 }}</ref> for one week ending 19 February 2007. The asteroid was estimated to be roughly {{convert|970|m|sp=us}} in diameter and had a virtual impactor listing a 1 in 625,000 chance of impact on 14 March 2012.<ref name=CA19/> It was removed from the risk table on February 22.<ref name="removed"/>
* '''2006'''
** {{mpl|(417634) 2006 XG|1}} was rated level 1 on December 22, 2006, when it had an observation arc of 25 days,<ref name=XG1>{{cite web|url=http://neo.jpl.nasa.gov/risk/2006xg1.html |title={{mp|2006 XG|1}} Impact Risk |work=Near Earth Object Program |publisher=NASA |url-status=dead |archive-url=https://web.archive.org/web/20070107205853/http://neo.jpl.nasa.gov/risk/2006xg1.html |archive-date=January 7, 2007 }}</ref> but was removed from the Sentry Risk Table on February 7, 2007.<ref name="removed"/>
** {{mpl|(292220) 2006 SU|49}} (with an observation arc of 7 days) showed a 1 in 42000 chance of impacting Earth on 22 January 2029.<ref name=SU49>{{cite web|url=http://neo.jpl.nasa.gov/risk/2006su49.html |title=2006 SU49 Impact Risk |work=Near Earth Object Program |publisher=NASA |url-status=dead |archive-url=https://web.archive.org/web/20060928234147/http://neo.jpl.nasa.gov/risk/2006su49.html |archive-date=September 28, 2006 }}</ref> It was removed from the Sentry Risk Table on 23 November 2006.<ref name="removed"/>
** {{mpl|(433953) 1997 XR|2}} was a lost asteroid from December 1997 that had an observation arc of 27 days.<ref name=XR2/> From early 2002 until 24 February 2006 it was estimated to have a 1 in 10,000 chance of impacting Earth on June 1, 2101.<ref name=XR2>{{cite web|url=http://neo.jpl.nasa.gov/risk/1997xr2.html |title=1997 XR2 Impact Risk |work=Near Earth Object Program |publisher=NASA |url-status=dead |archive-url=https://web.archive.org/web/20060207190049/http://neo.jpl.nasa.gov/risk/1997xr2.html |archive-date=February 7, 2006 }}</ref> It was removed from the risk table on 24 February 2006 when it was serendipitously rediscovered.<ref name="removed"/>
** {{mpl|(144898) 2004 VD|17}} (using an observation arc of 475 days) was upgraded to '''level 2''' in February 2006 for a possible 2102 encounter, making it the second asteroid rated above level 1.<ref name="VD17"/> It was downgraded to 0 after further observations. It was removed from the Sentry Risk Table on 14 February 2008.<ref name="removed"/>
* '''2005'''
** No asteroids reached Torino scale 1 in 2005.
* '''2004'''
** {{mpl|(99942) Apophis}} (a [[Astronomy:Near-Earth asteroid|near-Earth asteroid]] 370 meters in diameter) became the first object rated level 2 on 23 December 2004,<ref name="news146"/> and was subsequently upgraded to '''level 4''' — the current record for highest Torino rating.<ref name="news146"/> (It is now known Apophis will pass 38000&nbsp;km from Earth on 13 April 2029.) It retained a rating of level 1 for a 2036 approach due to the prior orbital uncertainties introduced by the close approach of 2029. In August 2006 Apophis was downgraded to 0. In 2021 Apophis was removed from the risk-list.
** {{mpl|(497117) 2004 FU|4}} was rated level 1 on 27 March 2004 with an observation arc of 6.9 days.<ref name="fu4">{{cite web |date=2004-03-27 |title=Major News about Minor Objects (2004 FU4) |publisher=hohmanntransfer |url=http://www.hohmanntransfer.com/mn/0403/27.htm#risks |access-date=2013-09-05 |archive-date=2011-06-15 |archive-url=https://web.archive.org/web/20110615113436/http://www.hohmanntransfer.com/mn/0403/27.htm#risks |url-status=dead }}</ref> It was lowered to 0 on 2 April 2004. It was removed on 13 April 2004.<ref name="removed"/>
** {{mpl|(144332) 2004 DV|24}} was rated level 1 on 1 March 2004 with an observation arc of 7.8 days.<ref name="dv24">{{cite web |date=2004-03-01 |title=Major News about Minor Objects (2004 DV24) |publisher=hohmanntransfer |url=http://www.hohmanntransfer.com/mn/0403/01.htm#risks |access-date=2013-09-05 |archive-date=2011-06-15 |archive-url=https://web.archive.org/web/20110615112632/http://www.hohmanntransfer.com/mn/0403/01.htm#risks |url-status=dead }}</ref> It was removed on 5 March 2004.<ref name="removed"/>
* '''2003'''
** {{mpl|(164121) 2003 YT|1}} was rated level 1 on 27 December 2003 with an observation arc of 8.7 days.<ref name="yt1">{{cite web |date=2003-12-27 |title=Major News about Minor Objects (2003 YT1) |publisher=hohmanntransfer |url=http://www.hohmanntransfer.com/mn/0312/27.htm#risks |access-date=2013-09-05 |archive-date=2013-04-25 |archive-url=https://web.archive.org/web/20130425080914/http://www.hohmanntransfer.com/mn/0312/27.htm#risks |url-status=dead }}</ref> It was removed from the risk table on 29 December 2003.<ref name="removed"/>
** {{mpl|(143651) 2003 QO|104}} was rated level 1 in early October 2003,<ref name="yt1"/> and removed on 13 October 2003.<ref name="removed"/>
** {{mpl|(143649) 2003 QQ|47}} was rated level 1 on 30 August 2003<ref name="QQ47"/> and removed from the Sentry Risk Table on 14 September 2003.<ref name="removed"/>
** {{mpl|(387746) 2003 MH|4}} was rated level 1 on 7 July 2003 with an observation arc of 10 days.<ref name=MH4>{{cite web|url=http://neo.jpl.nasa.gov/risk/2003mh4.html |title=2003 MH4 Impact Risk |work=Near Earth Object Program |publisher=NASA |url-status=dead |archive-url=https://web.archive.org/web/20030708080636/http://neo.jpl.nasa.gov/risk/2003mh4.html |archive-date=July 8, 2003 }}</ref> There was roughly an estimated 1 in 19,000 chance of impact on 9 June 2077.<ref name=MH4/> It was removed from the risk table on 29 July 2003.<ref name="removed"/>
** {{mpl|(177049) 2003 EE|16}} was rated level 1 on 2 April 2003,<ref name=EE16>{{cite web|url=http://neo.jpl.nasa.gov/risk/ |title=Current Impact Risks (2003 EE16) |work=Near-Earth Object Program |publisher=NASA |url-status=dead |archive-url=https://web.archive.org/web/20030402122939/http://neo.jpl.nasa.gov/risk/ |archive-date=April 2, 2003 }}</ref> and removed from the risk table on 28 May 2003.<ref name="removed"/>
* '''2002'''
** {{mpl|(89959) 2002 NT|7}} was rated level 1 on 24 July 2002,<ref>{{cite news |url=http://www.planetary.org/news/2002/0725_Asteroid_2002_NT7_Under_Watch_But.html |title=Asteroid 2002 NT7 Under Watch, But Probably Not Coming Our Way |author=A. J. S. Rayl |date=July 25, 2002 |work=Planetary News |publisher=The Planetary Society |url-status=dead |archive-url=https://web.archive.org/web/20060405010848/http://www.planetary.org/news/2002/0725_Asteroid_2002_NT7_Under_Watch_But.html |archive-date=2006-04-05 |access-date=2018-01-29}}</ref> and was removed from the risk table on 1 August 2002.<ref name="removed"/>
** {{mpl|(163132) 2002 CU|11}} was rated level 1 on 20 March 2002,<ref name=CU11>{{cite web|url=http://neo.jpl.nasa.gov/risk |title=Current Impact Risks (2002 CU11) |work=Near-Earth Object Program |publisher=NASA |url-status=dead |archive-url=https://web.archive.org/web/20020321092735/http://neo.jpl.nasa.gov/risk/ |archive-date=March 21, 2002 }}</ref> and completely removed from the Sentry Risk Table on 26 April 2002.<ref name="removed"/>

==See also==
*[[Astronomy:Asteroid impact avoidance|Asteroid impact avoidance]]
*[[Astronomy:Impact event|Impact event]]
*[[Palermo Technical Impact Hazard Scale]]

==References==
{{Reflist|30em
| refs =
<ref name="Torino-scale">{{cite web
  |date=13 Apr 2005
  |title=The Torino Impact Hazard Scale
  |publisher=NASA/JPL Near-Earth Object Program Office
  |url=http://neo.jpl.nasa.gov/torino_scale1.html
  |archive-url=https://web.archive.org/web/20041230031246/http://neo.jpl.nasa.gov/torino_scale1.html
  |url-status=dead
  |archive-date=30 December 2004
  |access-date=2011-11-05}}</ref>
<ref name="removed">{{cite web |url=http://neo.jpl.nasa.gov/risk/removed.html |archive-url=https://web.archive.org/web/20020602101400/http://neo.jpl.nasa.gov/risk/removed.html |url-status=dead |archive-date=2002-06-02 |title=NEOs Removed from Impact Risks Tables |work=Near Earth Object Program |publisher=NASA}}</ref>
<ref name="QQ47">{{cite web
  |date=September 3, 2003
  |title=Asteroid 2003 QQ47's Potential Earth Impact in 2014 Ruled Out
  |publisher=NASA/JPL Near-Earth Object Program Office
  |url=http://neo.jpl.nasa.gov/news/news138.html
  |archive-url=https://web.archive.org/web/20030906072157/http://neo.jpl.nasa.gov/news/news138.html
  |url-status=dead
  |archive-date=September 6, 2003
  |access-date=2011-11-06}}</ref>
<ref name="news146">{{cite web
  |date=December 23, 2004
  |title=Near-Earth Asteroid 2004 MN4 Reaches Highest Score To Date On Hazard Scale
  |publisher=NASA/JPL Near-Earth Object Program Office
  |author=Don Yeomans
  |author2=Steve Chesley
  |author3=Paul Chodas
  |name-list-style=amp
  |url=http://neo.jpl.nasa.gov/news/news146.html|archive-url=https://web.archive.org/web/20041225002324/http://neo.jpl.nasa.gov/news/news146.html|url-status=dead|archive-date=December 25, 2004}}</ref>
<ref name="VD17">{{cite web
 |date=March 1, 2006 
 |title=Asteroid 2004 VD17 classed as Torino Scale 2 
 |publisher=Asteroid and Comet Impact Hazards (NASA) 
 |author=David Morrison 
 |url=http://impact.arc.nasa.gov/news_detail.cfm?ID=167 
 |access-date=2011-11-06 
 |url-status=dead 
 |archive-url=https://web.archive.org/web/20111014235559/https://impact.arc.nasa.gov/news_detail.cfm?ID=167 
 |archive-date=October 14, 2011 
}}</ref>
<ref name="Melosh2011">{{cite web
| date = October 31, 2011
| title = Large asteroid to pass by Earth Nov. 8, but what if it didn't?
| publisher = Purdue University
| author = Elizabeth K. Gardner
| url = http://www.purdue.edu/newsroom/research/2011/111031T-MeloshAsteroid.html
| access-date = 2011-11-07
| archive-date = 2011-11-04
| archive-url = https://web.archive.org/web/20111104181655/http://www.purdue.edu/newsroom/research/2011/111031T-MeloshAsteroid.html
| url-status = live
}}</ref>
}}

{{Include-NASA}}

==External links==
* [https://cneos.jpl.nasa.gov/sentry/torino_scale.html The Torino Impact Hazard Scale] as part of the [[Astronomy:Sentry (monitoring system)|Sentry]] monitoring system by [[Organization:Center for Near-Earth Object Studies|CNEOS]] at [[Organization:Jet Propulsion Laboratory|JPL]] from [[Organization:NASA|NASA]]
* [https://web.archive.org/web/20070224184143/http://impact.arc.nasa.gov/torino.cfm Asteroid and Comet Impact Hazards: The Torino Scale] from [[Organization:NASA|NASA]]'s [[Organization:Ames Research Center|Ames Research Center]] in the [[Internet Archive]]
* [https://newton.spacedys.com/neodys/index.php?pc=4.1 Impact Risk Page] from [[Astronomy:NEODyS|NEODyS]]

{{Planetary defense}}

[[Category:American inventions]]
[[Category:Units of measurement in astronomy]]

{{Sourceattribution|Torino scale|1}}