The Torino scale is a method for categorizing the
impact
Impact may refer to:
* Impact (mechanics), a high force or shock (mechanics) over a short time period
* Impact, Texas, a town in Taylor County, Texas, US
Science and technology
* Impact crater, a meteor crater caused by an impact event
* Impac ...
hazard associated with
near-Earth object
A near-Earth object (NEO) is any small Solar System body whose orbit brings it into proximity with Earth. By convention, a Solar System body is a NEO if its closest approach to the Sun (perihelion) is less than 1.3 astronomical units (AU). ...
s (NEOs) such as
asteroid
An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere.
...
s and
comet
A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ar ...
s.
It is intended as a communication tool for
astronomer
An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, g ...
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
The Palermo Technical Impact Hazard Scale is a logarithmic scale used by astronomers to rate the potential hazard of impact of a near-Earth object (NEO). It combines two types of data—probability of impact and estimated kinetic yield— ...
is a similar, but more complex scale. Near-Earth objects with a Torino scale of 1 pop up every couple of months or so and may last a few weeks until they have a longer
observation arc
In observational astronomy, the observation arc (or arc length) of a Solar System body is the time period between its earliest and latest observations, used for tracing the body's path. It is usually given in days or years. The term is mostly use ...
.
Overview
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
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
, compared with the usual "background noise" of collision events, or is too small to penetrate
Earth's atmosphere
The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing for ...
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
kinetic energy
In physics, the kinetic energy of an object is the energy that it possesses due to its motion.
It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its accele ...
(expressed in
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."
[ Torino Impact Scale (NASA Ames)]
History and naming
The Torino Scale was created by Professor
Richard P. Binzel in the Department of Earth, Atmospheric, and Planetary Sciences, at the
Massachusetts Institute of Technology
The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the ...
(MIT). The first version, called "A Near-Earth Object Hazard Index", was presented at a
United Nations
The United Nations (UN) is an intergovernmental organization whose stated purposes are to maintain international peace and international security, security, develop friendly relations among nations, achieve international cooperation, and be ...
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 (
Turin
Turin ( , Piedmontese language, Piedmontese: ; it, Torino ) is a city and an important business and cultural centre in Northern Italy. It is the capital city of Piedmont and of the Metropolitan City of Turin, and was the first Italian capital ...
), 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.")
[
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 ]Rio scale
The Rio scale was proposed in 2000 as a means of quantifying the significance of a SETI detection. The scale was designed by Iván Almár and Jill Tarter to help policy-makers how likely, from 0 to 10, is that an extraterrestrial radio signal has ...
which quantifies the validity and societal impact of SETI
The search for extraterrestrial intelligence (SETI) is a collective term for scientific searches for intelligent extraterrestrial life, for example, monitoring electromagnetic radiation for signs of transmissions from civilizations on other p ...
data.
Current Torino scale
The Torino Scale also uses a color code scale: white, green, yellow, orange, red. Each color code has an overall meaning:
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 Chicxulub impact
The Chicxulub crater () is an impact crater buried underneath the Yucatán Peninsula in Mexico. Its center is offshore near the community of Chicxulub, after which it is named. It was formed slightly over 66 million years ago when a large a ...
, believed by most scientists to have been a significant factor in the extinction of the non-avian dinosaurs, has been estimated at 100 million (108) megatons, or Torino Scale 10. The impacts which created the Barringer Crater
Meteor Crater, or Barringer Crater, is a meteorite impact crater about east of Flagstaff, Arizona, Flagstaff and west of Winslow, Arizona, Winslow in the desert of northern Arizona, United States. The site had several earlier names, and fr ...
and the 1908 Tunguska event
The Tunguska event (occasionally also called the Tunguska incident) was an approximately 12-megaton explosion that occurred near the Podkamennaya Tunguska River in Yeniseysk Governorate (now Krasnoyarsk Krai), Russia, on the morning of June 30, ...
are both estimated to be in the 3–10 megaton
Megaton may refer to:
* A million tons
* Megaton TNT equivalent, explosive energy equal to 4.184 petajoules
* megatonne, a million tonnes, SI unit of mass
Other uses
* Olivier Megaton (born 1965), French film director, writer and editor
* ''Me ...
range, corresponding to Torino Scale 8. The 2013 Chelyabinsk meteor
The Chelyabinsk meteor was a superbolide that entered Earth's atmosphere over the southern Ural (region), Ural region in Russia on 15 February 2013 at about 09:20 Yekaterinburg Time, YEKT (03:20 Coordinated Universal Time, UTC). It was caused ...
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.
The biggest hydrogen bomb
A thermonuclear weapon, fusion weapon or hydrogen bomb (H bomb) is a second-generation nuclear weapon design. Its greater sophistication affords it vastly greater destructive power than first-generation nuclear bombs, a more compact size, a lowe ...
ever exploded, the Tsar Bomba
The Tsar Bomba () ( code name: ''Ivan'' or ''Vanya''), also known by the alphanumerical designation "AN602", was a thermonuclear aerial bomb, and the most powerful nuclear weapon ever created and tested. Overall, the Soviet physicist Andrei Sa ...
, was around 50 megatons.
The 1883 eruption of Krakatoa
The 1883 eruption of Krakatoa ( id, Letusan Krakatau 1883) in the Sunda Strait occurred from 20 May until 21 October 1883, peaking in the late morning hours of 27 August when over 70% of the island of Krakatoa and its surrounding archipelago w ...
was the equivalent of roughly 200 megatons.
The comet C/2013 A1
C/2013 A1 (Siding Spring) is an Oort cloud comet discovered on 3 January 2013 by Robert H. McNaught at Siding Spring Observatory using the Uppsala Southern Schmidt Telescope.
At the time of discovery it was 7.2 AU from the Sun and locat ...
, which passed close to Mars
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...
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. The impact probability was reduced to ~1:120000 in April 2013, corresponding to Torino Scale 1 or 2.
Objects with non-zero Torino ratings
Currently non-zero
* none
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 Sentry Risk Table
Sentry is a highly automated impact prediction system operated by the JPL Center for NEO Studies (CNEOS) since 2002. It continually monitors the most up-to-date asteroid catalog for possibilities of future impact with Earth over the next 100+ y ...
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.
* 2002
** was rated level 1 on 20 March 2002, and completely removed from the Sentry Risk Table on 26 April 2002.
** was rated level 1 on 24 July 2002, and was removed from the risk table on 1 August 2002.
* 2003
** was rated level 1 on 2 April 2003, and removed from the risk table on 28 May 2003.
** was rated level 1 on 7 July 2003 with an observation arc of 10 days. There was roughly an estimated 1 in 19,000 chance of impact on 9 June 2077.[ It was removed from the risk table on 29 July 2003.]
** was rated level 1 on 30 August 2003 and removed from the Sentry Risk Table on 14 September 2003.
** was rated level 1 in early October 2003, and removed on 13 October 2003.
** was rated level 1 on 27 December 2003 with an observation arc of 8.7 days. It was removed from the risk table on 29 December 2003.
* 2004
** was rated level 1 on 1 March 2004 with an observation arc of 7.8 days. It was removed on 5 March 2004.
** was rated level 1 on 27 March 2004 with an observation arc of 6.9 days. It was lowered to 0 on 2 April 2004. It was removed on 13 April 2004.
** (a near-Earth asteroid
A near-Earth object (NEO) is any small Solar System body whose orbit brings it into proximity with Earth. By convention, a Solar System body is a NEO if its closest approach to the Sun (perihelion) is less than 1.3 astronomical units (AU). ...
370 meters in diameter) became the first object rated level 2 on 23 December 2004, and was subsequently upgraded to level 4 — the current record for highest Torino rating. (It is now known Apophis will pass 38000 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.
* 2005
** No asteroids reached Torino scale 1 in 2005.
* 2006
** (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. It was downgraded to 0 after further observations. It was removed from the Sentry Risk Table on 14 February 2008.
** was a lost asteroid
A minor planet is "lost" when today's observers cannot find it, because its location is too uncertain to target observations. This happens if the orbital elements of a minor planet are not known accurately enough, typically because the observat ...
from December 1997 that had an observation arc of 27 days.[ 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.] It was removed from the risk table on 24 February 2006 when it was serendipitously rediscovered.
** (with an observation arc of 7 days) showed a 1 in 42000 chance of impacting Earth on 22 January 2029. It was removed from the Sentry Risk Table on 23 November 2006.
** was rated level 1 on December 22, 2006, when it had an observation arc of 25 days, but was removed from the Sentry Risk Table on February 7, 2007.
* 2007
** was rated level 1 for one week ending 19 February 2007. The asteroid was estimated to be roughly in diameter and had a virtual impactor listing a 1 in 625,000 chance of impact on 14 March 2012.[ It was removed from the risk table on February 22.]
** was rated level 1 on 3 July 2007 with an observation arc of 19 days. The asteroid was estimated to be in diameter and there was a 1 in 556,000 chance of impact on 11 July 2082.[ It was removed from the risk table on 15 July 2007.]
* 2008
** was rated level 1 until 14 February 2008. It was removed from the risk table on 19 December 2009.
* 2009
** was rated level 1 after its discovery in May 2009 (with a 15-day observation arc), and downgraded to 0 by 11 June 2009. It was removed 17 June 2009.
** was rated level 1 after its discovery on 17 November 2009, and downgraded by the end of November. It was not removed from the risk table until 26 June 2013.
** was rated level 1 on 28 December 2009 (with an observation arc of 10 days). It was downgraded to 0 by the end of December.
* 2010
** was rated level 1 in February 2010, 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.
** was rated level 1 on 18 May 2010 with an observation arc of 7 days. There was roughly an estimated 1 in 77,000 chance of impact on 26 June 2058.[ It was removed on 23 May 2010.]
** was rated level 1 in December 2010, and downgraded to 0 on 2 January 2011.
* 2011
** was rated level 1 on 13 February 2011 with an observation arc of 13.8 days.[ There was a 1 in 24,000 chance of impact on 18 January 2086.] It was removed from the risk table on 10 March 2011.
** was rated level 1 on 28 September 2011 with an observation arc of 2.6 days and listed virtual impactors in 2016 and 2019. But it was quickly downgraded to 0 a few days later and was removed from the risk table on 7 October 2011.
** is an asteroid with a diameter of 2.6 km, which was rated level 1 on October 27, 2011 (with an observation arc of 9.6 days.) It was downgraded to 0 a few days later.
** was rated level 1 on 4 November 2011 with an observation arc of 9 days. There was a 1 in 56,000 chance of impact on 8 July 2079.[ It was removed 17 November 2011.]
* 2012
** was rated level 1 on 21 February 2012 (with an observation arc of 8.9 days). It was removed from the risk table on 3 March 2012.
** was rated at Torino scale 1 on 23 June 2012 with an observation arc of 4 days. 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.
** was rated at Torino scale 1 from February 2011 to December 2012, for an impact on 5 February 2040. It was downgraded thanks to observations collected in October 2012 with telescopes on Mauna Kea
Mauna Kea ( or ; ; abbreviation for ''Mauna a Wākea''); is a dormant volcano on the island of Hawaii. Its peak is above sea level, making it the highest point in the state of Hawaii and second-highest peak of an island on Earth. The peak is ...
, Hawaii.
* 2013
** (a near-Earth asteroid with a 450 m diameter) was rated level 1 on 16 October 2013 (with an observation arc of 7.3 days). It was downgraded to 0 on 3 November 2013. It was completely removed from the Sentry Risk Table on 8 November 2013 using JPL solution 32 with an observation arc of 27 days.
* 2014
** 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. It was lowered to Torino Scale 0 on the next day (24 February 2014).
** was listed on the Near Earth Object Risk List with a Torino Scale of Level 1 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 , and travels through space with a speed of 15.6 km/s relative to Earth.
* 2015
** 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, 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 observation arc
In observational astronomy, the observation arc (or arc length) of a Solar System body is the time period between its earliest and latest observations, used for tracing the body's path. It is usually given in days or years. The term is mostly use ...
, it had an estimated 1 in 36,000 chance of impacting Earth on 5 October 2096.[ It was discovered on 12 July 2015 by ]Pan-STARRS
The Panoramic Survey Telescope and Rapid Response System (Pan-STARRS1; List of observatory codes, obs. code: IAU code#F51, F51 and Pan-STARRS2 obs. code: IAU code#F52, F52) located at Haleakala Observatory, Hawaii, US, consists of astronomical c ...
. The asteroid is estimated to have a diameter of , and would impact Earth at a relative speed of .[
** was listed on ]NEODyS
NEODyS (Near Earth Objects Dynamic Site) is an Italian service that provides information on near-Earth objects with a Web-based interface. It is based on a continually and (almost) automatically maintained database of near earth asteroid orbits. T ...
with a Torino Scale of Level 1 on 23 August 2015. Sentry
Sentry or The Sentry may refer to:
Comics
*Sentry (Kree)
*Sentry (Curtis Elkins)
*Sentry (Robert Reynolds)
*Senator Ward (comics) or Sentry
Vehicles
*Sentry (AUV), an autonomous underwater vehicle used to measure deep-ocean data
* E-3 Sentry AWAC ...
also listed it with a Torino Scale of Level 1 on 24 August 2015. With a 10-day observation arc
In observational astronomy, the observation arc (or arc length) of a Solar System body is the time period between its earliest and latest observations, used for tracing the body's path. It is usually given in days or years. The term is mostly use ...
, it had an estimated 1 in 84,000 chance of impacting Earth on 15 January 2081.[ It was downgraded to level 0 on 8 September 2015. It was discovered on 13 August 2015 by the ]Space Surveillance Telescope
The Space Surveillance Telescope (SST) is a military telescope for detecting, tracking and cataloguing satellites, near-Earth objects and space debris.
SST achieved first light in 2011 at the White Sands Missile Range
White Sands Missile ...
. The asteroid is estimated to have a diameter of .
* 2016
** was rated at level 1 for a day on 25 January 2016 by the NEODyS
NEODyS (Near Earth Objects Dynamic Site) is an Italian service that provides information on near-Earth objects with a Web-based interface. It is based on a continually and (almost) automatically maintained database of near earth asteroid orbits. T ...
system, and downgraded to level 0 the following day. On the Sentry
Sentry or The Sentry may refer to:
Comics
*Sentry (Kree)
*Sentry (Curtis Elkins)
*Sentry (Robert Reynolds)
*Senator Ward (comics) or Sentry
Vehicles
*Sentry (AUV), an autonomous underwater vehicle used to measure deep-ocean data
* E-3 Sentry AWAC ...
system it never crossed the threshold between the two levels, due to a lower computed impact probability.
** was rated at level 1 by NEODyS
NEODyS (Near Earth Objects Dynamic Site) is an Italian service that provides information on near-Earth objects with a Web-based interface. It is based on a continually and (almost) automatically maintained database of near earth asteroid orbits. T ...
on 25 March 2016, but subsequently lowered to zero thanks to prediscovery observations by the Pan-STARRS
The Panoramic Survey Telescope and Rapid Response System (Pan-STARRS1; List of observatory codes, obs. code: IAU code#F51, F51 and Pan-STARRS2 obs. code: IAU code#F52, F52) located at Haleakala Observatory, Hawaii, US, consists of astronomical c ...
survey. The asteroid is estimated to have a diameter of about .
** was listed on the JPL Near Earth Object Risk List with a Torino Scale of Level 1 on 25 November 2016, 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 observation arc
In observational astronomy, the observation arc (or arc length) of a Solar System body is the time period between its earliest and latest observations, used for tracing the body's path. It is usually given in days or years. The term is mostly use ...
, it had an estimated 1 in 8000 chance of impacting Earth on 12 June 2065.[ It was discovered on 19 November 2016 by Mt. Lemmon Survey.] The asteroid is estimated to have a diameter of , and would have impacted Earth at a relative speed of .[ 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.
** was listed on the JPL Near Earth Object Risk List with a Torino Scale of Level 1 on 25 December 2016,] 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.[ The asteroid is estimated to have a diameter of , and would have impacted Earth at a relative speed of .][ It was removed from the Sentry Risk Table on 7 January 2017 with a 29-day observation arc.
* 2017
** 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.] With a 14-day observation arc
In observational astronomy, the observation arc (or arc length) of a Solar System body is the time period between its earliest and latest observations, used for tracing the body's path. It is usually given in days or years. The term is mostly use ...
, it had an estimated 1 in 59,000 chance of impacting Earth on 1 August 2024.[ The asteroid is estimated to have a diameter of , and would impact Earth at a relative speed of .][ 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.
** 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.] With a 5-day observation arc
In observational astronomy, the observation arc (or arc length) of a Solar System body is the time period between its earliest and latest observations, used for tracing the body's path. It is usually given in days or years. The term is mostly use ...
, it had an estimated 1 in 1610 chance of impacting Earth on 3 August 2029.[ With a 6-day observation arc, the odds were 1 in 1270.][ With a 7-day observation arc, the odds were 1 in 909.][ With a 10-day observation arc, the odds were 1 in 826.][ The asteroid is estimated to have a diameter of , and would impact Earth at a relative speed of .][ The value decreased to 0 with further observations on February 11, with a cumulative impact chance of 1 in 4258.
** was listed on the NEODyS Risk List with a Torino Scale of Level 1 on 8 February 2017.] It is estimated be 900 meters in diameter with a 1 in 500000 chance of impact on 4 June 2095.[ Such an impact could create a crater 10 km in diameter. 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.
* 2018
** 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 , and would impact Earth at a relative speed of . 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 was downgraded to Level 0.
** 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 ]observation arc
In observational astronomy, the observation arc (or arc length) of a Solar System body is the time period between its earliest and latest observations, used for tracing the body's path. It is usually given in days or years. The term is mostly use ...
, it had an estimated 1 in 3000 chance of impacting Earth on 28 April 2057. The asteroid is estimated to have a diameter of about . The nominal 2057 Earth approach distance was estimated at 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 was removed from the Sentry Risk Table.
** (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. 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.
** was removed from the Sentry monitoring list on 14 June 2018 after having been on the Risk List with a Torino Scale of Level 1.
* 2019
** No asteroids reached Torino scale 1 in 2019.
* 2020
** (diameter ~700 meters) with a 13-day observation arc showed a 1 in 180,000 chance of impact on 14 October 2046. But the nominal solution had the asteroid 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.
** (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. 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.
** (diameter ~600 meters) initially showed, with a 7.6 day observation arc, a 1 in 83,000 chance of impact on 3 August 2093. 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. 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. The nominal distance from Earth on 4 August 2101 is . It was removed from the sentry risk table entirely on July 31 with a 15.6 day observation arc.
** (diameter ~390 meters) with a 5 day observation arc showed a 1 in 11,000 chance of impact on 1 December 2028 and a nominal distance from Earth on 1 December 2028 of 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 . 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.
* 2021
** (diameter ~200 meters) with a 7.6 day observation arc showed a 1 in 6,700 chance of impact on 3 May 2034. With a 7 day arc, the nominal distance from Earth on 3 May 2034 was with an uncertainty region of ±20 million km. 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
The Dark Energy Survey (DES) is an astronomical survey designed to constrain the properties of dark energy. It uses images taken in the near-ultraviolet, visible, and near-infrared to measure the expansion of the universe using Type Ia supernov ...
and Pan-STARRS
The Panoramic Survey Telescope and Rapid Response System (Pan-STARRS1; List of observatory codes, obs. code: IAU code#F51, F51 and Pan-STARRS2 obs. code: IAU code#F52, F52) located at Haleakala Observatory, Hawaii, US, consists of astronomical c ...
archives.
** (diameter ~300 meters) with a 18.9 day observation arc showed a 1 in 56,000 chance of impact on 27 March 2081. The nominal distance from Earth on 27 March 2081 was estimated at with an uncertainty region of ±870 million km. 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.
* 2022
** (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. The nominal distance from Earth on 4 July 2023 was estimated as small as 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.
** (diameter ~160 meters) with a 22 day observation arc showed a 1 in 7,700 chance of impact on 11 July 2061. It was lowered to Torino Scale 0 with a 24 day observation arc. The nominal distance from Earth on 11 July 2061 is with an uncertainty region of ±600 thousand km.
** (diameter ~40 meters) with a 8 day observation arc showed a 1-in-109 chance of impact on 4 September 2068. The nominal distance from Earth on 4 September 2068 is now known to be with an uncertainty region of ±32 thousand km.
** (diameter ~170 meters) with a 25 day observation arc showed a 1 in 2,000 chance of impact on 2 April 2064.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 with a 3-sigma uncertainty region of about ±8 million km.[(ESA CA: 2022UE28)]
/ref>
See also
*Asteroid impact avoidance
Asteroid impact avoidance comprises the methods by which near-Earth objects (NEO) on a potential collision course with Earth could be diverted away, preventing destructive impact events. An impact by a sufficiently large asteroid or other NEOs ...
*Impact event
An impact event is a collision between astronomical objects causing measurable effects. Impact events have physical consequences and have been found to regularly occur in planetary systems, though the most frequent involve asteroids, comets or me ...
*Palermo Technical Impact Hazard Scale
The Palermo Technical Impact Hazard Scale is a logarithmic scale used by astronomers to rate the potential hazard of impact of a near-Earth object (NEO). It combines two types of data—probability of impact and estimated kinetic yield— ...
References
External links
The Torino Impact Hazard Scale
as part of the Sentry
Sentry or The Sentry may refer to:
Comics
*Sentry (Kree)
*Sentry (Curtis Elkins)
*Sentry (Robert Reynolds)
*Senator Ward (comics) or Sentry
Vehicles
*Sentry (AUV), an autonomous underwater vehicle used to measure deep-ocean data
* E-3 Sentry AWAC ...
monitoring system by CNEOS at JPL from NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research.
NASA was established in 1958, succeeding t ...
Asteroid and Comet Impact Hazards: The Torino Scale
from NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research.
NASA was established in 1958, succeeding t ...
's Ames Research Center
The Ames Research Center (ARC), also known as NASA Ames, is a major NASA research center at Moffett Federal Airfield in California's Silicon Valley. It was founded in 1939 as the second National Advisory Committee for Aeronautics (NACA) laborat ...
in the Internet Archive
The Internet Archive is an American digital library with the stated mission of "universal access to all knowledge". It provides free public access to collections of digitized materials, including websites, software applications/games, music, ...
Impact Risk Page
from NEODyS
NEODyS (Near Earth Objects Dynamic Site) is an Italian service that provides information on near-Earth objects with a Web-based interface. It is based on a continually and (almost) automatically maintained database of near earth asteroid orbits. T ...
{{Portal bar, Physics, Mathematics, Astronomy, Stars, Spaceflight, Outer space, Science
American inventions
Alert measurement systems
Hazard scales
Units of measurement in astronomy
Planetary defense