NationMaster - Encyclopedia: 2004 MN4

2004 MN₄ (also written 2004 MN4) is a Near-Earth asteroid that caused a brief period of concern in late 2004. Initial observations of the asteroid revealed a relatively large probability that 2004 MN₄ would strike the Earth in 2029. However, additional observations provided improved predictions that essentially eliminated the possibility of an impact on Earth or the Moon. The close approach of 2004 MN4 to the Earth and Moon on April 13, 2029 The small white bar indicates uncertainty in the range of possible positions. ... The close approach of 2004 MN4 to the Earth and Moon on April 13, 2029 The small white bar indicates uncertainty in the range of possible positions. ... April 13 is the 103rd day of the year in the Gregorian calendar (104th in leap years). ... 2029 is a Common year starting on Monday. ... The close approach of 2004 MN4 to the Earth and Moon on April 13, 2029 The white bar indicates uncertainty in the range of possible positions. ... The close approach of 2004 MN4 to the Earth and Moon on April 13, 2029 The white bar indicates uncertainty in the range of possible positions. ... Near-Earth asteroids (NEAs) are asteroids whose orbit intersects Earths orbit and which may therefore pose a collision danger, as well as being most easily accessible for spacecraft from Earth. ... 2004 is a leap year starting on Thursday of the Gregorian calendar. ... 2029 is a Common year starting on Monday. ... Artists impression of a major impact event. ... Crust composition Oxygen 43% Silicon 21% Aluminium 10% Calcium 9% Iron 9% Magnesium 5% Titanium 2% Nickel 0. ...

Nevertheless, it is expected that it will come close enough that on April 13, 2029 (Friday the 13th) it will become as bright as magnitude 3.3 (easily visible to the naked eye). This close approach will be visible from Europe, Africa, and western Asia. No other closely approaching objects in recorded history have been visible to the naked eye. April 13 is the 103rd day of the year in the Gregorian calendar (104th in leap years). ... 2029 is a Common year starting on Monday. ... Look up paraskavedekatriaphobia in Wiktionary, the free dictionary Friday the 13th is considered to be a day of bad luck in many superstitions. ... The apparent magnitude (m) of a star, planet or other heavenly body is a measure of its apparent brightness; that is, the amount of light received from the object. ... A naked eye is a figure of speech, referring to human eyes unaided by enhancing equipment such as a telescope or binoculars. ... World map showing location of Europe A satellite composite image of Europe Europe is geologically and geographically a peninsula, forming the westernmost part of Eurasia. ... World map showing location of Africa A satellite composite image of Africa Africa is the worlds second-largest continent in both area and population, after Asia. ... World map showing location of Asia A satellite composite image of Asia Asia is the central and eastern part of the continent of Eurasia, defined by subtracting the European peninsula from Eurasia. ...

2004 MN₄ remains at level one on the Torino scale because of very low but nonzero probabilities of impact on approaches in 2035, 2036 and 2037. However, the approach in 2029 will substantially alter the object's orbit, and the precise details of its future orbit or any future close approaches will only be known after that has happened. The Torino Scale is a method for categorizing the impact hazard associated with near-Earth objects (NEOs) such as asteroids and comets. ... Centuries: 20th century - 21st century - 22nd century Decades: 1980s 1990s 2000s 2010s 2020s - 2030s - 2040s 2050s 2060s 2070s 2080s Years: 2030 2031 2032 2033 2034 - 2035 - 2036 2037 2038 2039 2040 Event January 8 - Near-Earth object 2002 AY1 will make a close approach to Earth. ... Centuries: 20th century - 21st century - 22nd century Decades: 1980s 1990s 2000s 2010s 2020s - 2030s - 2040s 2050s 2060s 2070s 2080s Years: 2031 2032 2033 2034 2035 - 2036 - 2037 2038 2039 2040 2041 Events India to overtake China as worlds most populous country. ... Centuries: 20th century - 21st century - 22nd century Decades: 1980s 1990s 2000s 2010s 2020s - 2030s - 2040s 2050s 2060s 2070s 2080s Years: 2032 2033 2034 2035 2036 - 2037 - 2038 2039 2040 2041 2042 Events January 31 - Near-Earth object 2002 OD20 will make a close approach to Earth. ... 2029 is a Common year starting on Monday. ...

Contents

1 Basic data

2 Discovery

3 History of estimates

4 Possible impact effects

5 See also

6 External links

6.1 Risk assessment
6.2 NASA press releases
6.3 Older articles
6.4 More recent articles

Basic data

2004 MN₄ belongs to a group called the "Aten asteroids", asteroids with an orbital semi-major axis less than one astronomical unit. This particular asteroid 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). ... In geometry, the semi-major axis (also semimajor axis) a applies to ellipses and hyperbolas. ... The astronomical unit (AU or au or a. ...

Based upon the observed brightness 2004 MN₄'s length was estimated at 410 m (1350 ft); a more refined estimate based on radar observations is 320 m (1050 ft). Its mass is estimated to be 4.6×10¹⁰ kg. metre or meter, see meter (disambiguation) The metre is the basic unit of length in the International System of Units. ... This article is about a foot as a unit of length. ... This long range radar antenna (approximately 40m (130ft) in diameter) rotates on a track to observe activities near the horizon. ... (Redirected from 1 E 10 kg) Categories: Orders of magnitude (mass) ...

As of February 2005 it is predicted that the asteroid will pass about 36,350 km (22,600 miles) from the Earth's surface on April 13, 2029, slightly higher than the altitude of geosynchronous satellites, which orbit at 35,786 km (22,300 miles). It will become as bright as magnitude 3.3, moving as fast as 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 only 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. ... April 13 is the 103rd day of the year in the Gregorian calendar (104th in leap years). ... 2029 is a Common year starting on Monday. ... A geosynchronous satellite is a satellite whose orbital speed equals the Earths rotational speed. ... 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

2004 MN₄ was discovered on June 19, 2004, by Roy 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. June 19 is the 170th day of the year (171st in leap years) in the Gregorian Calendar, with 195 days remaining. ... 2004 is a leap year starting on Thursday of the Gregorian calendar. ... David J. Tholen is an American astronomer. ... The National Aeronautics and Space Administration (NASA) (established 1958) is the government agency responsible for the United States of Americas space program and long-term general aerospace research. ... Jean Charlots mural called Commencement is featured at Bachman Hall, the administrative center of the University of Hawai`i System. ... The Kitt Peak National Observatory (KPNO) is located on a 6,875 ft peak of the Quinlan Mountains in the Arizona-Sonoran Desert on the Tohono Oodham Nation, 55 miles southwest of Tucson. ... State nickname: The Grand Canyon State, The Copper State Other U.S. States Capital Phoenix Largest city Phoenix Governor Janet Napolitano Official languages English Only State Area 295,254 km² (6th) - Land 294,312 km² - Water 942 km² (0. ...

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. December 18 is the 352nd day of the year (353rd in leap years) in the Gregorian Calendar. ... Siding Spring Observatory, Coonabarabran, Australia. ... The Minor Planet Center operates at the Smithsonian Astrophysical Observatory, affiliated with Harvard University. ...

At this point the possibility of impact on April 13, 2029 was computed 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 detected the impact possibility and provided similar predictions. April 13 is the 103rd day of the year in the Gregorian calendar (104th in leap years). ... 2029 is a Common year starting on Monday. ... The University of Pisa (Italian Università degli Studi di Pisa) is one of the major renowned Italian universities. ...

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 percent (1 in 37). Combined with its size, this caused 2004 MN₄ 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. ...

The asteroid was precovered to 2004-March 15.1104, and an improved orbital prediction was released on December 27. This path removed the chance of an impact in 2029, and dropped the cumulative odds of impact over the entire 21st century to 0.0041 percent (1 in 24,000). As of January 15, 2005, the cumulative Palermo scale rating for 2004 MN₄ is −1.59 and the Torino scale rating is 1. The predicted orbit still brings the asteroid well within the orbit of the Moon in 2029, and 2004 MN₄'s path will be noticeably deflected by Earth's gravity. 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. ... 2004 is a leap year starting on Thursday of the Gregorian calendar. ... March 15 is the 74th day of the year in the Gregorian Calendar (75th in Leap years). ... December 27 is the 361st day of the year in the Gregorian Calendar. ... (20th century - 21st century - 22nd century - other centuries) Decades: 2000s 2010s 2020s 2030s 2040s 2050s 2060s 2070s 2080s 2090s In calendars based on the Christian Era or Common Era, such as the Gregorian calendar, the 21st century is the current century, as of this writing, lasting from 2001-2100. ... January 15 is the 15th day of the year in the Gregorian Calendar. ... 2005 is a common year starting on Saturday of the Gregorian calendar. ...

History of estimates

The original NASA report on December 24 mentioned impact chances of "around 1 in 300", which was widely reported in the media. 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 percent), 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 percent) and later that day (based on 101 observations) as 1 in 45 (2.2 percent). 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 percent), 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 has been raised to 1 in 37 (2.7 percent); diameter has increased to 390 m, and mass to 7.9×10¹⁰ kg.
On December 27 in the afternoon, precovered observation 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 is estimated to be around 0.004 percent, 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 2004 MN₄ is still rated at level one on the Torino scale for this orbit. Like the 2029 approach, further observations will almost certainly resolve the possibility of this impact date to be insignificant as well.
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, 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, 204 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 by the Arecibo Observatory on January 27, 28, and 30 refine the orbit still further. Three passes at 1 (Torino Scale) in 2035, 2036, 2037.

December 24 is the 358th day of the year in the Gregorian Calendar (359th in leap years). ... December 25 is the 359th day of the year (360th in leap years) in the Gregorian Calendar, with 6 days remaining. ... December 26 is the 360th day of the year in the Gregorian Calendar, 361st in leap years. ... December 27 is the 361st day of the year in the Gregorian Calendar. ... December 27 is the 361st day of the year in the Gregorian Calendar. ... 2004 VD17 (also written 2004 VD17) is a near-Earth asteroid that was discovered on November 7, 2004 by the NASA-funded LINEAR asteroid survey. ... December 28 is the 362nd day of the year (363rd in leap years) in the Gregorian Calendar, with 3 days remaining. ... December 29 is the 363rd day of the year (364th in leap years) in the Gregorian Calendar, with 2 days remaining. ... December 29 is the 363rd day of the year (364th in leap years) in the Gregorian Calendar, with 2 days remaining. ... December 30 is the 364th day of the year (365th in leap years) in the Gregorian Calendar, with 1 day remaining. ... December 30 is the 364th day of the year (365th in leap years) in the Gregorian Calendar, with 1 day remaining. ... The Torino Scale is a method for categorizing the impact hazard associated with near-Earth objects (NEOs) such as asteroids and comets. ... January 2 is the 2nd day of the year 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. ... January 3 is the 3rd day of the year 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. ... This long range radar antenna (approximately 40m (130ft) in diameter) rotates on a track to observe activities near the horizon. ... The Arecibo Observatory is located in Arecibo, Puerto Rico on the north coast of the island. ... January 27 is the 27th day of the year in the Gregorian Calendar. ... January 28 is the 28th day of the year in the Gregorian Calendar. ... January 30 is the 30th day of the year 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. ... Centuries: 20th century - 21st century - 22nd century Decades: 1980s 1990s 2000s 2010s 2020s - 2030s - 2040s 2050s 2060s 2070s 2080s Years: 2030 2031 2032 2033 2034 - 2035 - 2036 2037 2038 2039 2040 Event January 8 - Near-Earth object 2002 AY1 will make a close approach to Earth. ... Centuries: 20th century - 21st century - 22nd century Decades: 1980s 1990s 2000s 2010s 2020s - 2030s - 2040s 2050s 2060s 2070s 2080s Years: 2031 2032 2033 2034 2035 - 2036 - 2037 2038 2039 2040 2041 Events India to overtake China as worlds most populous country. ... Centuries: 20th century - 21st century - 22nd century Decades: 1980s 1990s 2000s 2010s 2020s - 2030s - 2040s 2050s 2060s 2070s 2080s Years: 2032 2033 2034 2035 2036 - 2037 - 2038 2039 2040 2041 2042 Events January 31 - Near-Earth object 2002 OD20 will make a close approach to Earth. ...

Possible impact effects

Because the odds of impact are now negligible, the effects of such an event are largely irrelevant. However, for several days armchair speculation about exactly where 2004 MN₄ would hit and what would happen when it did was common on many internet forums.

NASA initially estimated the energy that 2004 MN₄ would have released if it impacted Earth as the equivalent of 1480 megatons of TNT (114,000 times the energy from the nuclear bomb Little Boy, dropped by the United States on Hiroshima, Japan). A more refined later estimate was 850 megatons. The impacts which created the Barringer Meteor Crater or caused the Tunguska event are estimated to be in the 10-20 megaton range. 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. ... Trinitrotoluene (TNT) is a pale yellow crystalline aromatic hydrocarbon compound that melts at 354 K (178 °F). ... The mushroom cloud of the atomic bombing of Nagasaki, Japan, 1945, rose some 18 km (11 mi) above the epicenter. ... Little Boy bomb casing Little Boy was the codename given to the nuclear weapon dropped on Hiroshima, Japan on Monday, August 6, 1945. ... Citizens of Hiroshima walk by the A-Bomb Dome, the closest building to have survived the citys atomic bombing. ... For the town that was formerly named Hiroshima in Hokkaido, see Kitahiroshima. ... For the crater on the Moon, see the Lunar Barringer crater 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 USA). ... The Tunguska event was an aerial explosion that occurred at 60° 55’ North, 101° 57’ East, near the Podkamennaya (Stony) Tunguska River in what is now Evenkia, Siberia, at 7:17 AM on June 30, 1908. ... An early 19th century image of Krakatoa. ...

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 kilometers, but would have been unlikely to have long-lasting global effects, such as the precipitation of an impact winter. An impact winter is caused by debris from an impact of an asteroid or comet obscuring the sun. ...

Based on the predicted time of impact (0.89 of a day, or about 21:21 UTC) and the fact that the asteroid would be approaching the Earth from outside of its orbit, the impact was likely to occur in the Eastern Hemisphere (time zones UTC +3 to UTC +10). The Eastern Hemisphere of the Earth is a little-used concept because there is no obvious demarcation line separating it from the Western Hemisphere, to act the way the equator divides the Northern and Southern Hemispheres. ... UTC also stands for the University of Tennessee at Chattanooga Coordinated Universal Time or UTC, also sometimes referred to as Zulu time, is an atomic realization of Universal Time or Greenwich mean time, the astronomical basis for civil time. ...

Any potential impact would have occurred at a velocity of 12.59 km/s.

External links

Risk assessment

These sources are updated as new orbital data becomes available:

2004 MN₄ Impact Risk (http://neo.jpl.nasa.gov/risk/2004mn4.html) (NASA JPL)
2004 MN4 page (http://newton.dm.unipi.it/cgi-bin/neodys/neoibo?objects:2004MN4;main) and 2004 MN4 impactor table (http://newton.dm.unipi.it/cgi-bin/neodys/neoibo?objects:2004MN4;risk) 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. ...

NASA press releases

Near-Earth Asteroid 2004 MN4 Reaches Highest Score To Date On Hazard Scale (http://neo.jpl.nasa.gov/news/news146.html) (JPL)
Possibility of an Earth Impact in 2029 Ruled Out for Asteroid 2004 MN4 (http://neo.jpl.nasa.gov/news/news148.html) (JPL)
Radar Observations Refine the Future Motion of Asteroid 2004 MN4 (http://neo.jpl.nasa.gov/news/news149.html) (JPL)

Older articles

Whew! Asteroid Won't Hit Earth in 2029, Scientists Now Say (http://www.space.com/scienceastronomy/asteroid_update_B_041227.html) (SPACE.com)
Asteroid Watch: Odds of 2029 Collision Stuck at 1-in-40 (http://www.space.com/scienceastronomy/asteroid_update_041227.html) (SPACE.com)
Worrisome Asteroid Underscores Planetary Defense Mission (http://www.space.com/news/asteroid_defense_041227.html) (SPACE.com)

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