Close approach of Apophis on April 13, 2029

The white bar indicates uncertainty in the range of positions

99942 Apophis

99942 Apophis (pronounced /əˈpoʊfɪs/, previously known by its provisional designation 2004 MN₄) is a near-Earth asteroid that caused a brief period of concern in December 2004 because initial observations indicated a relatively large probability (up to 2.7%) that it would strike the Earth in 2029. Additional observations provided improved predictions that eliminated the possibility of an impact on Earth or the Moon in 2029. However there remained a possibility that during the 2029 close encounter with Earth, Apophis would pass through a gravitational keyhole, a precise region in space no more than about 400 meters across, that would set up a future impact on April 13, 2036. This possibility kept the asteroid at Level 1 on the Torino impact hazard scale until August 2006. It broke the record for the highest level on the Torino Scale, being, for only a short time, a level 4, before it was lowered.^[4] Roy A. Tucker is an American astronomer. ... David J. Tholen is an American astronomer at the Institute for Astronomy of the University of Hawaii, who specializes in planetary and solar system astronomy. ... is the 170th day of the year (171st in leap years) in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... Provisional designation of in astronomy is the naming convention applied to astronomical objects immediately following their discovery. ... The Aten asteroids are a group of near-Earth asteroids, named after the first of the group to be discovered (2062 Aten, discovered January 7, 1976 by Eleanor F. Helin). ... Two bodies with a slight difference in mass orbiting around a common barycenter. ... In astronomy, an epoch is a moment in time for which celestial coordinates or orbital elements are specified. ... is the 330th day of the year (331st in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... “JDN” redirects here. ... A diagram of Keplerian orbital elements. ... A diagram of Keplerian orbital elements. ... The semi-major axis of an ellipse In geometry, the term semi-major axis (also semimajor axis) is used to describe the dimensions of ellipses and hyperbolae. ... Look up giga- in Wiktionary, the free dictionary. ... This article is about the unit of length. ... The astronomical unit (AU or au or a. ... (This page refers to eccitricity in astrodynamics. ... The orbital period is the time it takes a planet (or another object) to make one full orbit. ... Look up day in Wiktionary, the free dictionary. ... In astronomy, a Julian year is a unit of time defined as exactly 365. ... The orbital speed of a body, generally a planet, a natural satellite, an artificial satellite, or a multiple star, is the speed at which it orbits around the barycenter of a system, usually around a more massive body. ... This article is about the unit of time. ... In the study of orbital dynamics the mean anomaly is a measure of time, specific to the orbiting body p, which is a multiple of 2π radians at and only at periapsis. ... For the science fiction novella by William Shunn, see Inclination (novella). ... This article describes the unit of angle. ... The Longitude of the ascending node (☊, also noted Ω) is one of the orbital elements used to specify the orbit of an object in space. ... The argument of periapsis (ω) is the orbital element describing the angle between an orbiting bodys ascending node (the point where the body crosses the plane of reference from South to North) and its periapsis (the point of closest approach to the central body), measured in the orbital plane and... This article is about the unit of length. ... For other uses, see Mass (disambiguation). ... (Redirected from 1 E 10 kg) Categories: Orders of magnitude (mass) ... Kg redirects here. ... For other uses, see Density (disambiguation). ... A cubic centimetre (cm3) is an SI derived unit of volume, equal to the volume of a cube with side length of 1 centi metre. ... The surface gravity of a Killing horizon is the acceleration, as exerted at infinity, needed to keep an object at the horizon. ... Space Shuttle Atlantis launches on mission STS-71. ... Kilometres per hour (American spelling: kilometers per hour) is a unit of both speed (scalar) and velocity (vector). ... In astronomy, a rotation period is the time an astronomical object takes to complete one revolution around its rotation axis relative to the background stars. ... The hour (symbol: h) is a unit of time. ... For other uses, see Albedo (disambiguation). ... For other uses, see Temperature (disambiguation). ... For other uses, see Kelvin (disambiguation). ... In astronomy, absolute magnitude is the apparent magnitude, m, an object would have if it were at a standard luminosity distance away from us, in the absence of interstellar extinction. ... is the 103rd day of the year (104th in leap years) in the Gregorian calendar. ... 2029 (MMXXIX) will be a common year starting on Monday of the Gregorian calendar. ... Image File history File links 2004MN4_Sormano. ... Image File history File links 2004MN4_Sormano. ... Provisional designation of in astronomy is the naming convention applied to astronomical objects immediately following their discovery. ... Computer model of the Apollo Asteroid 6489 Golevka Near-Earth asteroids (NEAs) are asteroids whose orbits are close to Earths orbit. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... 2029 (MMXXIX) will be a common year starting on Monday of the Gregorian calendar. ... Artists impression of a major impact event. ... This article is about Earths moon. ... gravitational keyhole ... is the 103rd day of the year (104th in leap years) in the Gregorian calendar. ... 2036 (MMXXXVI) will be a leap year starting on Tuesday of the Gregorian calendar. ... The Torino Scale is a method for categorizing the impact hazard associated with near-Earth objects (NEOs) such as asteroids and comets. ... The Torino Scale is a method for categorizing the impact hazard associated with near-Earth objects (NEOs) such as asteroids and comets. ...

Additional observations of the trajectory of Apophis revealed the "keyhole" would likely be missed and on August 5, 2006, Apophis was lowered to a Level 0 on the Torino Scale. As of October 19, 2006, the impact probability for April 13, 2036, was calculated as 1 in 45,000. An additional impact date in 2037 was also identified; however, the impact probability for that encounter was calculated as 1 in 12.3 million.
The Planetary Society has awarded $50,000 in prize money to a company designing a space probe that would put a tracking device on or near the asteroid.^[5] is the 217th day of the year (218th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... The Torino Scale is a method for categorizing the impact hazard associated with near-Earth objects (NEOs) such as asteroids and comets. ... This article is in need of attention. ...

Basic data

Apophis belongs to a group called the "Aten asteroids", asteroids with an orbital semi-major axis less than one astronomical unit. This particular one has an orbital period about the Sun of 323 days, and its path brings it across Earth's orbit twice on each passage around the Sun. The Aten asteroids are a group of near-Earth asteroids, named after the first of the group to be discovered (2062 Aten, discovered January 7, 1976 by Eleanor F. Helin). ... The semi-major axis of an ellipse In geometry, the term semi-major axis (also semimajor axis) is used to describe the dimensions of ellipses and hyperbolae. ... The astronomical unit (AU or au or a. ...

Based upon the observed brightness, Apophis's length was estimated at 415 m (1350 ft); a more refined estimate based on spectroscopic observations at NASA's Infrared Telescope Facility in Hawaii by Binzel, Rivkin, Bus, and Tokunaga (2005) is 350 m (1150 ft). Its mass is estimated to be 4.6×10¹⁰ kg. This article is about the unit of length. ... A foot (plural: feet or foot;[1] symbol or abbreviation: ft or, sometimes, ′ – a prime) is a unit of length, in a number of different systems, including English units, Imperial units, and United States customary units. ... (Redirected from 1 E 10 kg) Categories: Orders of magnitude (mass) ...

As of February 2005 it is predicted that the asteroid will pass just below the altitude of geosynchronous satellites, which are at 35,786 km (22,300 mi). Apophis' brightness will peak at magnitude 3.3, with a maximum angular speed of 42° per hour. Such a close approach by an asteroid of this size is expected to occur only every 1,300 years or so. The maximum apparent angular diameter will be ~2 arcseconds, which means it will be a starlike point of light in all but the very largest telescopes. 2005 is a common year starting on Saturday of the Gregorian calendar. ... A geosynchronous satellite is a satellite whose orbital track on the Earth repeats regularly over points on the Earth over time. ... The apparent magnitude (m) of a star, planet or other celestial body is a measure of its apparent brightness as seen by an observer on Earth. ... The angular diameter of an object as seen from a given position is the diameter measured as an angle. ... A second of arc or arcsecond is a unit of angular measurement which comprises one-sixtieth of an arcminute, or 1/3600 of a degree of arc or 1/1296000 ≈ 7. ...

Discovery

Apophis was discovered on June 19, 2004, by Roy A. Tucker, David J. Tholen, and Fabrizio Bernardi of the NASA-funded University of Hawaii Asteroid Survey from Kitt Peak National Observatory in Arizona. This group observed for two nights. The new object received the provisional designation 2004 MN₄. is the 170th day of the year (171st in leap years) in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... Roy A. Tucker is an American astronomer. ... David J. Tholen is an American astronomer at the Institute for Astronomy of the University of Hawaii, who specializes in planetary and solar system astronomy. ... For other uses, see NASA (disambiguation). ... This article is about the University of Hawaii system. ... The Kitt Peak National Observatory (KPNO) is a United States astronomical observatory located on a 2,096 m (6,880 ft) peak of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono Oodham Nation, 88 kilometres (55 miles) southwest of Tucson. ... Official language(s) English Spoken language(s) English 74. ... The provisional designation of comets and asteroids are similar to each other: they both follow a pattern set in 1925 by the Minor Planet Center of the IAU. Historical designations At first, astronomers strove to assign symbols to the minor planets: 1 Ceres a stylized sickle 2 Pallas a lozenge...

On December 18, the object was rediscovered from Australia by Gordon Garradd of the Siding Spring Survey, another NASA-funded NEA survey. Further observations from around the globe over the next several days allowed the Minor Planet Center to confirm the connection to the June discovery. is the 352nd day of the year (353rd in leap years) in the Gregorian calendar. ... Gordon J. Garradd is an Australian astronomer. ... The Anglo-Australian Telescope at Siding Spring Observatory Siding Spring Observatory near Coonabarabran, Australia, part of the Research School of Astronomy & Astrophysics (RSAA) at the Australian National University (ANU), incorporates the Anglo-Australian Telescope along with a collection of other telescopes owned by the Australian National University, the University of... The Minor Planet Center operates at the Smithsonian Astrophysical Observatory (SAO), which is part of the Center for Astrophysics (CfA) along with the Harvard College Observatory (HCO). ...

Naming

When first discovered, the object received the provisional designation 2004 MN₄ (sometimes written 2004 MN4), and news and scientific articles about it referred to it by that name. When its orbit was sufficiently well calculated it received the permanent number 99942 (on June 24, 2005), the first numbered asteroid with Earth-impact solutions (to its orbit determination from observations). Receiving a permanent number made it eligible for naming, and it promptly received the name "Apophis" as of July 19, 2005. Apophis is the Greek name of the Ancient Egyptian enemy of Ra: Apep, the Uncreator, a serpent that dwells in the eternal darkness of the Duat (underworld) and tries to swallow Ra during His nightly passage. Apep is held at bay by Set, the Ancient Egyptian god of Chaos. The provisional designation of comets and asteroids are similar to each other: they both follow a pattern set in 1925 by the Minor Planet Center of the IAU. Historical designations At first, astronomers strove to assign symbols to the minor planets: 1 Ceres a stylized sickle 2 Pallas a lozenge... is the 175th day of the year (176th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... This article is about the Egyptian demon. ... is the 200th day of the year (201st in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... For the Cypriot football team, see APEP Kyperounda FC. An Egyptian deity wards off the snake-like Apep [1] In Egyptian mythology, Apep (also spelled Apepi, and Aapep, or Apophis in Greek) was an evil demon, the deification of darkness and chaos (isfet in Egyptian), and thus opponent of light... In Egyptian mythology, Duat (also called Akert or Amenthes) is the underworld, where the sun traveled from west to east during the night and where dead souls were judged by Osiris, using a feather, representing Truth. ...

Although the Greek name for the Egyptian god may be appropriate, Tholen and Tucker (two of the co-discovers of the asteroid) are reportedly fans of the TV series Stargate SG-1. The show's main antagonist in the first several seasons was an alien named Apophis who took the name for the Egyptian god and sought to destroy Earth.^[6] Stargate SG-1 (often abbreviated as SG-1) is a science fiction television series, part of the Stargate franchise. ... In the science fiction television show Stargate SG-1, Apophis was a Goauld based on the god Apep of Egyptian mythology. ...

Close approaches

After the Minor Planet Center confirmed the June discovery of Apophis (then known only as 2004 MN₄), the next close approach was computed to be April 13, 2029 by the automatic Sentry system of NASA's Near-Earth Object Program Office. NEODyS, a similar automatic system at the University of Pisa, Italy and the University of Valladolid, Spain also calculated this same approach date. On that date, it will become as bright as magnitude 3.3 (visible to the naked eye from rural and some darker suburban areas, visible with binoculars from most locations^[7]). This close approach will be visible from Europe, Africa, and western Asia. As a result of its close passage, it will move from the Aten (see below) to the Apollo class. The Minor Planet Center operates at the Smithsonian Astrophysical Observatory (SAO), which is part of the Center for Astrophysics (CfA) along with the Harvard College Observatory (HCO). ... is the 103rd day of the year (104th in leap years) in the Gregorian calendar. ... 2029 (MMXXIX) will be a common year starting on Monday of the Gregorian calendar. ... Sentry is a highly automated collision monitoring system that continually scans the most current asteroid catalog for possibilities of future impact with Earth over the next 100 years. ... NEODyS (Near Earth Objects Dynamic Site) is a Italian-based service that tracks all near-earth asteroids, including calculation of orbital elements and impact threat assessment. ... The University of Pisa (Italian Università di Pisa) is one of the most renowned Italian universities. ... The University of Valladolid is believed to be the oldest university in the Spanish-speaking world, having been founded at the beginning of the 13th century[1]. It currently has 31,780 undergraduate students and over 2,000 faculty[2]. External links Official Website(Spanish language) Official Website in English... The apparent magnitude (m) of a star, planet or other celestial body is a measure of its apparent brightness as seen by an observer on Earth. ... The naked eye is a figure of speech referring to human visual perception that is unaided by enhancing equipment, such as a telescope or binoculars. ... Porro-prism binoculars with central focusing Binocular telescopes, or binoculars, (also known as field glasses) are two identical or mirror-symmetrical telescopes mounted side-by-side and aligned to point accurately in the same direction, allowing the viewer to use both eyes (binocular vision) when viewing distant objects. ... For other uses, see Europe (disambiguation). ... A world map showing the continent of Africa Africa is the worlds second-largest and second most-populous continent, after Asia. ... For other uses, see Asia (disambiguation). ... The Aten asteroids are a group of near-Earth asteroids, named after the first of the group to be discovered (2062 Aten, discovered January 7, 1976 by Eleanor F. Helin). ... The Apollo asteroid 25143 Itokawa. ...

After the June discovery was confirmed, observatories throughout the world computed the probability of impact. Over the next several days, additional observations allowed for astronomers to narrow the cone of error. As they did, the probability of an impact event climbed, peaking at 2.7% (1 in 37). Combined with its size, this caused Apophis to be assessed at level four out of ten on the Torino Impact Hazard Scale and 1.10 on the Palermo scale, scales scientists use to represent the danger of an asteroid hitting Earth. These are the highest values for which any object has been rated on either scale. The Torino Scale is a method for categorizing the impact hazard associated with near-Earth objects (NEOs) such as asteroids and comets. ... 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. ...

On Friday, April 13, 2029, Apophis will pass the earth within the orbits of geosynchronous communication satellites.^[8] It will return for another close Earth approach in 2036. A geosynchronous orbit is a geocentric orbit that has the same orbital period as the sidereal rotation period of the Earth. ... U.S. military MILSTAR communications satellite A communications satellite (sometimes abbreviated to comsat) is an artificial satellite stationed in space for the purposes of telecommunications using radio at microwave frequencies. ...

Precovery observations from March 15, 2004 were identified on December 27, and an improved orbit was computed.^[9] Radar astrometry further refined the orbit. The 2029 pass will actually be much closer than the first predictions, but the uncertainty is such that an impact is ruled out. The pass on April 13, 2036 was also determined to carry little risk. Precovery is a term used in astronomy that describes the process of finding the image of an object (usually a minor planet) in old archived images or photographic plates, for the purpose of calculating a more accurate orbit. ... is the 74th day of the year (75th in leap years) in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... December 27 is the 361st day of the year in the Gregorian calendar (362nd in leap years). ... Radar images and computer model of asteroid 1998 JM8 Radar astronomy is a technique of observing nearby astronomical objects by reflecting microwaves off target objects and analyzing the echoes. ... is the 103rd day of the year (104th in leap years) in the Gregorian calendar. ... 2036 (MMXXXVI) will be a leap year starting on Tuesday of the Gregorian calendar. ...

The close approach in 2029 will substantially alter the object's orbit, making predictions uncertain without more data. "If we get radar ranging in 2013 [the next good opportunity], we should be able to predict the location of 2004 MN₄ out to at least 2070." said Jon Giorgini of JPL.^[10] 2029 (MMXXIX) will be a common year starting on Monday of the Gregorian calendar. ...

In July 2005, former Apollo astronaut Rusty Schweickart, as chairman of the B612 Foundation, formally asked NASA to investigate the possibility that the asteroid's post-2029 orbit could be in orbital resonance with the Earth, which would increase the probability of future impacts. Schweickart asked for an investigation of the necessity of placing a transponder on the asteroid for more accurate tracking of how its orbit is affected by the Yarkovsky effect.^[11] This article is about the series of human spaceflight missions. ... Russell Louis Rusty Schweickart (born October 25, 1935) is an American astronaut. ... The B612 Foundation is a private foundation dedicated to protecting the Earth from asteroid strikes. ... In celestial mechanics, an orbital resonance occurs when two orbiting bodies exert a regular, periodic gravitational influence on each other. ... In physics, the Yarkovsky effect is a force felt by a body caused by the momentum carried away by the thermal photons that it emits. ...

History of estimates

Illustration of a common trend where progressively reduced uncertainty regions result in an asteroid impact probability increasing followed by a sharp decrease.

• The original NASA report on December 23, 2004, mentioned impact chances of "around 1 in 300", which was widely reported in the media.^[4] The actual NASA estimates at the time were 1 in 233; they resulted in the Torino scale rating of 2, the first time any asteroid had received a rating above 1.
• Later that day, based on a total of 64 observations, the estimates were changed to 1 in 62 (1.6%), resulting in an update to the initial report and an upgrade to a Torino scale rating of 4.
• On December 25, the chances were first reported as 1 in 42 (2.4%) and later that day (based on 101 observations) as 1 in 45 (2.2%). At the same time, the asteroid's estimated diameter was lowered from 440 m to 390 m and its mass from 1.2×10¹¹ kg to 8.3×10¹⁰ kg.
• On December 26 (based on a total of 169 observations), the impact probability was still estimated as 1 in 45 (2.2%), the estimates for diameter and mass were lowered to 380 m and 7.5×10¹⁰ kg, respectively.
• On December 27 (based on a total of 176 observations), the impact probability was raised to 1 in 37 (2.7%); diameter was increased to 390 m, and mass to 7.9×10¹⁰ kg.
• On December 27 in the afternoon, a precovery increased the span of observations to 287 days and allowed more accurate calculations to re-rate the asteroid's 2029 approach as level zero on the Torino scale (no threat). The cumulative impact probability was estimated to be around 0.004%, a lower risk than asteroid 2004 VD₁₇, which once again became the greatest risk object (a position it had held since late November 2004). A 2053 approach to the earth still poses a minor risk of impact, and Apophis was still rated at level one on the Torino scale for this orbit.
• On December 28 at 12:23 GMT and (based on a total of 139 observations), produced a value of one on the Torino scale for 2044-04-13.29 and 2053-04-13.51.
• By 01:10 GMT on December 29 the only pass rated 1 on the Torino scale was for 2053-04-13.51 based on 139 observations spanning 287.71 days (2004-Mar-15.1104 to 2004-Dec-27.8243).
• By 19:18 GMT on December 29 this was still the case based upon 147 observations spanning 288.92 days (2004-Mar-15.1104 to 2004-Dec-29.02821), though the close encounters have changed and been reduced to 4 in total.
• By 13:46 GMT on December 30 no passes were rated above 0, based upon 157 observations spanning 289.33 days (2004-Mar-15.1104 to 2004-Dec-29.44434). The most dangerous pass was rated at 1 in 7,143,000.
• By 22:34 GMT on December 30, 157 observations spanning 289.33 days (2004-Mar-15.1104 to 2004-Dec-29.44434). One pass at 1 (Torino Scale) 3 other passes.
• By 03:57 GMT on January 2, 2005, 182 observations spanning 290.97 days (2004-Mar-15.1104 to 2004-Dec-31.07992) One pass at 1 (Torino Scale) 19 other passes.
• By 14:49 GMT on January 3, 2005 observations spanning 292.72 days (2004-Mar-15.1104 to 2005-Jan-01.82787) One pass at 1 (Torino Scale) 15 other passes.
• Extremely precise radar observations at Arecibo Observatory on January 27, 28, and 30 refine the orbit further and show that the April, 2029 close approach will occur at only 5.6 Earth radii, approximately one-half the distance previously estimated.
• A radar observation on August 7, 2005, refines the orbit further and eliminates the possibility of an impact in 2035. Only the pass in 2036 remains at Torino Scale 1.
• A new radar observation at Arecibo Observatory on May 6, 2006 slightly lowered the Palermo scale rating, but the pass in 2036 remained at Torino Scale 1 despite the impact probability dropping by a factor of four.
• Additional observations through 2006 resulted in Apophis being lowered to Torino Scale 0 on August 6, 2006.
• A 13-year-old German male, with the assistance of Professor Spahn of Potsdam University, and Professor Landgraf from ESA-Satelliten-Kontrollzentrum, has corrected NASA's estimates of Apophis colliding with Earth, after spotting an error in NASA's calculations. Nico Marquardt used telescopic findings from the Institute of Astrophysics in Potsdam (AIP) to reassess the calculation of an impact to 1 in 450 chance. NASA had previously estimated the chances at only one in 45,000 but told its sister organisation, the European Space Agency (ESA), that it believed Nico was correct. Nico took into consideration the risk of Apophis running into one or more of the 40,000 satellites orbiting Earth during its path close to the planet on April 13, 2029. If the asteroid strikes a satellite in 2029, that will change its trajectory making it hit Earth on its next orbit in 2036.^[12][13][14]

is the 357th day of the year (358th in leap years) in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... The Torino Scale is a method for categorizing the impact hazard associated with near-Earth objects (NEOs) such as asteroids and comets. ... is the 359th day of the year (360th in leap years) in the Gregorian calendar. ... is the 360th day of the year (361st in leap years) in the Gregorian calendar. ... December 27 is the 361st day of the year in the Gregorian calendar (362nd in leap years). ... December 27 is the 361st day of the year in the Gregorian calendar (362nd in leap years). ... 2004 VD17 (also written 2004 VD17) is a near-Earth asteroid with a low but non-zero probability of impacting Earth in 2102. ... is the 362nd day of the year (363rd in leap years) in the Gregorian calendar. ... is the 363rd day of the year (364th in leap years) in the Gregorian calendar. ... is the 363rd day of the year (364th in leap years) in the Gregorian calendar. ... is the 364th day of the year (365th in leap years) in the Gregorian calendar. ... is the 364th day of the year (365th in leap years) in the Gregorian calendar. ... The Torino Scale is a method for categorizing the impact hazard associated with near-Earth objects (NEOs) such as asteroids and comets. ... is the 2nd day of the year in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... The Torino Scale is a method for categorizing the impact hazard associated with near-Earth objects (NEOs) such as asteroids and comets. ... is the 3rd day of the year in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... The Torino Scale is a method for categorizing the impact hazard associated with near-Earth objects (NEOs) such as asteroids and comets. ... For other uses, see Radar (disambiguation). ... The Arecibo Observatory is located approximately 9 miles south-southwest from Arecibo, Puerto Rico (near the extreme southwestern corner of Arecibo pueblo). ... is the 27th day of the year in the Gregorian calendar. ... is the 28th day of the year in the Gregorian calendar. ... is the 30th day of the year in the Gregorian calendar. ... is the 219th day of the year (220th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... is the 126th day of the year (127th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 218th day of the year (219th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ...

Possible impact effects

NASA initially estimated the energy that Apophis would have released if it struck Earth as the equivalent of 1480 megatons of TNT. A later, more refined NASA estimate was 880 megatons. The impacts which created the Barringer Crater or caused the Tunguska event are estimated to be in the 3-10 megaton range^[15] The 1883 eruption of Krakatoa was the equivalent of roughly 200 megatons. A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ... R-phrases S-phrases Related Compounds Related compounds picric acid hexanitrobenzene Except where noted otherwise, data are given for materials in their standard state (at 25 Â°C, 100 kPa) Infobox disclaimer and references Trinitrotoluene (TNT) is a chemical compound with the formula C6H2(NO2)3CH3. ... The Barringer Crater, also known as the Meteor Crater, is a famous impact crater created by a meteorite, located about 55 kilometers east of Flagstaff in the northern Arizona desert (USA). ... Trees knocked over by the Tunguska blast. ... For the 1969 film about the Krakatoa eruption, see Krakatoa, East of Java. ...

Path of risk where 99942 Apophis may impact Earth in 2036.

The exact effects of any impact would have varied based on the asteroid's composition, and the location and angle of impact. Any impact would have been extremely detrimental to an area of thousands of square kilometres, but would have been unlikely to have long-lasting global effects, such as the initiation of an impact winter. An impact winter is a period of prolonged cold weather caused by the impact on the Earth of a large asteroid or comet. ...

The B612 Foundation made estimates of Apophis path if a 2036 Earth impact were to occur as part of an effort to develop viable deflection strategies.^[16] The result is a narrow corridor a few miles wide, called the path of risk, and it includes most of southern Russia, across the north Pacific (relatively close to the coastlines of the California and Mexico), then right between Nicaragua and Costa Rica, crossing northern Colombia and Venezuela, ending in the Atlantic, just before reaching Africa.^[17][18] Using the computer simulation tool NEOSim, it was estimated that the hypothetical impact of Apophis in countries such as Colombia and Venezuela, which are in the path of risk, would have had more than 10 million casualties.^[19] An impact several thousand miles off the West Coast of the US would have produced devastating tsunamis.^[20] The B612 Foundation is a private foundation dedicated to protecting the Earth from asteroid strikes. ... Artists impression of a major impact event. ... Anthem Hymn of the Russian Federation Capital (and largest city) Moscow Official languages Russian official throughout nation; thirty others co-official in various regions Government Semi-presidential federal republic  -  President Vladimir Putin  -  Prime Minister Mikhail Fradkov Formation  -  Declared June 12, 1990   -  Finalized December 25, 1991  Area  -  Total 17,075,400... For other meanings of Pacific, see Pacific (disambiguation). ... This article is about the U.S. state. ... The Atlantic Ocean is Earths second-largest ocean, covering approximately one_fifth of its surface. ... A world map showing the continent of Africa Africa is the worlds second-largest and second most-populous continent, after Asia. ...

Potential space mission

In 2008, The Planetary Society, a California-based space advocacy group, organized a $50,000 competition to design an unmanned space probe that would 'shadow' Apophis for almost a year, taking measurements that would "determine whether it will impact Earth, thus helping governments decide whether to mount a deflection mission to alter its orbit." The competition was won by a design called 'Foresight' created by SpaceWorks Engineering. The craft is planned to be launched in 2012.^[5] To keep mission costs low, the winning design, Foresight, proposes a simple orbiter with only two instruments and a radio beacon at a cost of $137.2 million. The spacecraft would launch aboard a Minotaur IV, leaving Earth sometime between 2012 and 2014, to arrive at Apophis five to ten months later. It would then rendezvous with, observe, and track the asteroid. Foresight would orbit the asteroid to gather data with a multi-spectral imager for one month. It would then leave orbit and fly in formation with Apophis around the Sun at a range of two kilometers (1.2 miles). The spacecraft would use laser ranging to the asteroid and radio tracking from Earth for ten months to accurately determine the asteroid's orbit and how it might change. 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... The Planetary Society is a large, publicly-supported, not-for-profit organization that has many research projects related to astronomy. ... This article is about the U.S. state. ... 2012 (MMXII) will be a leap year starting on Sunday of the Gregorian calendar. ... The Minotaur I Rocket is an American solid fuel rocket designed to launch small satellites. ...

Pharos, the winning student entry, would be an orbiter with four science instruments (a multi-spectral imager, near-infrared spectrometer, laser rangefinder, and magnetometer) that would rendezvous with and track Apophis. Earth-based tracking of the spacecraft would then allow precise tracking of the asteroid. The Pharos spacecraft would also carry four instrumented probes that it would launch individually over the course of two weeks. Accelerometers and temperature sensors on the probes would measure the seismic effects of successive probe impacts, a creative way to explore the interior structure and dynamics of the asteroid.

The competition received 37 mission proposals from 20 countries on 6 continents. If Earth were ever going to mount a defense against a dangerous asteroid, international cooperation would be vital in protecting the planet. That spirit of international cooperation was exemplified by the second and third place teams.

Second place, for $10,000, went to a European team led by Deimos Space S.L. of Madrid, Spain, in cooperation with EADS Astrium, Friedrichshafen, Germany; University of Stuttgart, Germany; and Universitá di Pisa, Italy. Juan L. Cano was Principal Investigator. EADS Astrium, one of the three business units of EADS Space, this company being a subsidiary of EADS, is an European space manufacturer involved in the manufacture of spacecraft used for science, Earth observation and telecommunication, as well as the equipment and subsystems used therein and related ground systems. ... The Universität Stuttgart is the University of Stuttgart. ...

Another European team took home $5,000 for third place. Their team lead was EADS Astrium Ltd, United Kingdom, in conjunction with EADS Astrium SAS, France; IASF-Roma, INAF, Rome, Italy; Open University, UK; Rheinisches Institut für Umweltforschung, Germany; Royal Observatory of Belgium; and Telespazio, Italy. The Principal Investigator was Paolo D'Arrigo. The European Aeronautic Defence and Space Company EADS N.V. (EADS) is a large European aerospace corporation, formed by the merger on July 10, 2000 of Aérospatiale-Matra of France, Construcciones Aeronáuticas SA (CASA) of Spain, and DaimlerChrysler Aerospace AG (DASA) of Germany. ... Affiliations Alliance of Non-Aligned Universities, Association of Commonwealth Universities, European Association of Distance Teaching Universities, Middle States Association of Colleges and Schools Website http://www. ... Telespazio is a space systems services company. ...

Two teams tied for second place in the Student Category: Monash University, Clayton Campus, Australia, with Dilani Kahawala as Principal Investigator; and University of Michigan, with Jeremy Hollander as Principal Investigator. Each second place team won $2,000. A team from Hong Kong Polytechnic University and Hong Kong University of Science and Technology, under the leadership of Peter Weiss, received an honorable mention and $1,000 for the most innovative student proposal. Robert Menzies Building at the Clayton Campus Monash University is a public university with campuses located in Australia, Malaysia and South Africa. ... The University of Michigan, Ann Arbor (U of M, UM, U-M or simply Michigan) is a coeducational public research university in the state of Michigan. ... HK Polytechnic University The Hong Kong Polytechnic University (PolyU or HKPU) (Traditional Chinese: ) is located in Hung Hom, Hong Kong, right next to the Hung Hom KCR station and the Kowloon side of the Cross-Harbour Tunnel. ... This article contains a trivia section. ...

In addition to the unmanned Planetary Society project, NASA's Project Constellation is researching a manned Orion Asteroid Mission, with 99924 Apophis being one of the potential destinations of the mission. The mission would use the Orion spacecraft to land astronauts on the surface of the asteroid. Such a mission would provide valuable testing for a later manned Orion Mars Mission. For other uses, see NASA (disambiguation). ... Project Constellation is NASAs current plan for space exploration. ... The Orion Asteroid Mission is a propsoed mission to a Near-Earth Asteroid utilizing the standard Orion spacecraft and a landing module based on the Lunar Surface Access Module. ... Orion spacecraft in lunar orbit Orion spacecraft with docked LSAM lunar lander Orion spacecraft approaching the ISS Orion during a landing on Earth The Orion Spacecraft (formerly known as the Crew Exploration Vehicle or CEV) is a proposed series of American manned and unmanned spacecraft, intended to replace the Space...

Popular culture

• In March 2007 heavy metal band Type O Negative released the album Dead Again which contains the track "The Profits of Doom". The song references Apophis and its potential collision in 2029 and uses it as a metaphor for the Biblical book of Revelation.

March 2007 is the third month of the year. ... This article is about the band. ... Dead Again is the seventh studio album by Type O Negative, released through SPV/Steamhammer. ... Revelation of the Last Judgment by Jacob de Backer Revelation is an uncovering or disclosure via communication from the divine of something that has been partially or wholly hidden or unknown, which could not be known apart from the unveiling (Goswiller 1987 p. ...

See also

• List of noteworthy asteroids
• Asteroid deflection strategies
• Asteroid naming conventions

The following is a collection of lists of noteworthy asteroids in the Solar system, sometimes also including minor planets beyond the orbit of Jupiter. ... Artists impression of a major impact event. ... The provisional designation of comets and asteroids are similar to each other: they both follow a pattern set in 1925 by the Minor Planet Center of the IAU. Historical designations At first, astronomers strove to assign symbols to the minor planets: 1 Ceres a stylized sickle 2 Pallas a lozenge...

References

2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 33rd day of the year in the Gregorian calendar. ... For other uses, see Volume (disambiguation). ... In astronomy, rubble pile is the informal name for an asteroid that is not a monolith, consisting instead of numerous pieces of rock that have coalesced under the influence of gravity. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 33rd day of the year in the Gregorian calendar. ... is the 357th day of the year (358th in leap years) in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 228th day of the year (229th in leap years) in the Gregorian calendar. ... This article is in need of attention. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 57th day of the year in the Gregorian calendar. ... is the 230th day of the year (231st in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... The Harvard-Smithsonian Center for Astrophysics (CfA) is located in Cambridge, Massachusetts. ... The Minor Planet Circulars (MPCs) (also known as Minor Planets and Comets) are published generally on the date of each full moon by the Minor Planet Center. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... December 27 is the 361st day of the year in the Gregorian calendar (362nd in leap years). ... December 17 is the 351st day of the year (352nd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 29th day of the year in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 53rd day of the year in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 53rd day of the year in the Gregorian calendar. ...

Further reading

• Cooke, Bill. (2006) Fatal attraction. Astronomy, May 2006, 46-51.
• Fountain, Henry (27 November 2005). "Saving Earth from the next heavenly blow". New Straits Times, p. F24.

Astronomy is a monthly American magazine dealing with issues about astronomy. ... is the 331st day of the year (332nd in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... Not to be confused with The Straits Times, the Singaporean newspaper. ...

External links

Wikimedia Commons has media related to:

99942 Apophis

Risk assessment

These sources are updated as new orbital data becomes available:

• Apophis Orbital Prediction Page at NASA JPL
• 2004 MN₄ Impact Risk (NASA JPL)
• 2004 MN₄ page and 2004 MN₄ impactor table from NEODyS.

NEODyS (Near Earth Objects Dynamic Site) is a Italian-based service that tracks all near-earth asteroids, including calculation of orbital elements and impact threat assessment. ...

ESA

• May we deflect asteroids? (Advanced Concepts Team)

NASA

• Near-Earth Asteroid 2004 MN₄ Reaches Highest Score To Date On Hazard Scale (JPL)
• Possibility of an Earth Impact in 2029 Ruled Out for Asteroid 2004 MN₄ (JPL)
• Radar Observations Refine the Future Motion of Asteroid 2004 MN₄ (JPL)
• Animation explaining how impact risk is determined from [1]

Older articles

• Whew! Asteroid Won't Hit Earth in 2029, Scientists Now Say (SPACE.com)
• Asteroid Watch: Odds of 2029 Collision Stuck at 1-in-40 (SPACE.com)
• Worrisome Asteroid Underscores Planetary Defense Mission (SPACE.com)

More recent articles

• Astronauts propose 'tractor-pull' of asteroid
• Closest Flyby of Large Asteroid to be Naked-Eye Visible (2029 approach)
• Asteroid 2004 MN₄: A Really Near Miss! (Sky and Telescope)
• An asteroid, headed our way (Christian Science Monitor, on efforts to deflect the asteroid if needed)
• Astronauts want plan to prevent cosmic collision
• Probabilistic Design of a Planetary Defense System
• Chandler, David (October 13, 2007). Asteroid is 'practice case' for potential hazards. MIT. Retrieved on 2007-10-16.

Navbox/core Sky & Telescope is a monthly magazine providing articles and information on all aspects of astronomy, space exploration, telescope equipment, and amateur telescope making and use. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 289th day of the year (290th in leap years) in the Gregorian calendar. ... Minor planets, or asteroids or planetoids, are minor celestial bodies of the Solar system orbiting the Sun (mostly Small solar system bodies) that are smaller than major planets, but larger than meteoroids (commonly defined as being 10 meters across or less[1]), and that are not comets. ... List of asteroids List of comets See also Trans-Neptunian object Categories: Solar System ...