2002 AA₂₉

Discovery
Discovered by	LINEAR
Discovery date	January 9, 2002
Designations
Alternate name(s)	none
Minor planet category	Aten asteroid
Orbital characteristics
Epoch November 22, 2002 (JD 2452600.5)
Aphelion	1.012 AU (151.442 Gm)
Perihelion	0.988 AU (147.735 Gm)
Semi-major axis	1.000 AU (149.588 Gm)
Eccentricity	0.012
Orbital period	365.222 d (1.00 a)
Average orbital speed	29.784 km/s
Mean anomaly	225.947°
Inclination	10.739°
Longitude of ascending node	106.849°
Argument of perihelion	91.594°
Proper orbital elements
Physical characteristics
Dimensions	~0.06 km
Mass	~2.3×108 kg
Mean density	2 ? g/cm³
Equatorial surface gravity	~0.000 017 m/s²
Escape velocity	~0.000 032 km/s
Albedo	0.1 ?
Temperature	~279 K
Absolute magnitude (H)	24.08

2002 AA₂₉ (also written 2002 AA29) is a small near-Earth asteroid that was discovered on January 9, 2002 by the LINEAR (Lincoln Near Earth Asteroid Research) automatic sky survey. The diameter of the asteroid is only about 50 to 110 metres (160 to 360 feet). It revolves about the Sun on an almost circular orbit very similar to that of the Earth. This lies for the most part inside the Earth's orbit, which it crosses near the asteroid's furthest point from the Sun, the aphelion. Because of this orbit, the asteroid is classified as Aten type, named after the asteroid (2062) Aten.

A further characteristic is that its mean orbital period about the Sun is exactly one sidereal year. This means that it is locked into a relationship with the Earth, since such an orbit is only stable under particular conditions. As yet only a few asteroids of this sort are known, locked into a 1:1 resonance with the Earth. The first was (3753) Cruithne, discovered in 1986.

Asteroids that have a 1:1 orbital resonance with a planet are also called co-orbital objects, because they follow the orbit of the planet. The most numerous known co-orbital asteroids are the so-called Trojans, which occupy the L4 and L5 Lagrangian points of the relevant planet. However, 2002 AA₂₉ does not belong to these. Instead, it follows a so-called horseshoe orbit along the path of the Earth.

Orbit[link]

Orbital data[link]

Shortly after the discovery by LINEAR, Scientists at the Jet Propulsion Laboratory (JPL), the Athabasca University (Canada), the Queen’s University in Kingston (Ontario, Canada), the York University in Toronto and the Tuorla Observatory of the University of Turku in Finland determined the unusual orbit of 2002 AA₂₉, and through further observations at the Canada–France–Hawaii Telescope in Hawaii it was confirmed that:

Orbits of 2002 AA₂₉ and the Earth about the Sun, looking down on the ecliptic plane from above the Sun's North Pole; Image: JPL

• Its orbit lies for the most part inside the Earth’s orbit. The orbits of most asteroids lie in the so-called asteroid belt between Mars and Jupiter. Through orbital disturbances by the gas giant planets, mainly Jupiter, and through the Yarkovsky effect (force due to asymmetrical absorption and emission of infra-red radiation) asteroids are diverted into the inner Solar System, where their orbits further influenced by close approaches with the inner planets. 2002 AA₂₉ has probably been brought in the same way from the outer Solar System into the Earth’s influence. However, it is also suggested that the asteroid has always been on a near-Earth orbit and thus that it or a precursor body was formed near Earth’s orbit. In this case one possibility is that it could be a fragment from a collision of a middle-sized asteroid with the Earth or the Moon.^[1]

• Its mean orbital period is one sidereal year. After it was diverted into the inner Solar System – or formed on a path near the Earth’s orbit – the asteroid must have been moved into an orbit corresponding with the Earth. In this orbit it was repeatedly pulled by the Earth in such a way that its own orbital period became the same as that of the Earth. In the current orbit, the Earth thus holds the asteroid in synchronicity with its own orbit.

Orbits of 2002 AA₂₉ and the Earth about the Sun, seen from the side; Image: JPL

• The orbit of the asteroid is almost circular, with an eccentricity of 0.012 which is even lower than that of the Earth at 0.0167. The other near-Earth asteroids have on average a significantly higher eccentricity of 0.29. Also, all other asteroids in 1:1 resonance with the Earth known before 2002 have very strongly elliptical orbits – e.g. the eccentricity of (3753) Cruithne is 0.515. At the time of its discovery the orbit of 2002 AA₂₉ was unique, because of which the asteroid is often called the first true co-orbital companion of the Earth, since the paths of previously discovered asteroids are not very similar to the Earth’s orbit. The very low orbital eccentricity of 2002 AA₂₉ is also an indication that it must always have been on a near-Earth orbit, or the Yarkovsky effect must have comparatively strongly caused it to spiral into the inner Solar System over billions of years, since as a rule asteroids which have been steered by planets have orbits with higher eccentricity.

• The orbital inclination with respect to the ecliptic (orbital plane of the Earth) of 2002 AA₂₉ is a moderate 10.739°. Hence its orbit is slightly tilted compared with that of the Earth; if it were not tilted at all, the orbits would lie right on top of each other.

Shape of the orbit[link]

Horseshoe orbit of 2002 AA29. The graphic shows a full revolution of 95 years. The position of 2002 AA₂₉ along the orbit is that of year 2003 (last nearest approach to Earth). Image: JPL

If one looks at the orbit of 2002 AA₂₉ from a point moving with the Earth around the Sun (the reference frame of the Earth–Sun system), it describes over the course of 95 years an arc of almost 360°, which during the next 95 years it retraces in reverse. The shape of this arc is reminiscent of a horseshoe, from which comes the name “horseshoe orbit”. As it moves along the Earth's orbit, it winds in a spiral about it, in which each loop of the spiral takes one year. This spiral motion (in the Earth–Sun reference frame) arises from the slightly lower eccentricity and the tilt of the orbit: the inclination relative to the Earth's orbit is responsible for the vertical component of the spiral loop, and the difference in eccentricity for the horizontal component.

When 2002 AA₂₉ is approaching the Earth from in front (i.e. it is moving slightly slower, and the Earth is catching it up), the gravitational attraction of the Earth shifts it onto a slightly faster orbit, a little nearer the Sun. It now hurries ahead of the Earth along its new orbit, until after 95 years it has almost lapped the Earth and is coming up from behind. Again it comes under the Earth's gravitational influence; this time it is lifted onto a slower orbit, further from the Sun. On this orbit it can no longer keep pace with the Earth, and it falls behind until in 95 years it is once again approaching the Earth from in front. The Earth and 2002 AA₂₉ chase each other in turn around the Sun, but do not get close enough to break the pattern.

On 8 January 2003 the asteroid approached the Earth from in front to a distance of 5.9 million kilometres (3.7 million miles), its closest approach for nearly a century. Since that date it has been hurrying ahead, and will continue to do so until it has reached its closest approach from behind. As a result of this subtle exchange with the Earth, unlike other Earth orbit crossing asteroids, we need have no fear that it could ever collide with the Earth. Calculations indicate that in the next few thousand years it will never come closer than 4.5 million kilometres, or about twelve times the distance from the Earth to the Moon.

Quasi-satellite orbit of 2002 AA₂₉ in the year 2589, looking vertically down on the ecliptic. Left, orbits of Asteroid and Earth in the reference frame of the fixed stars; right, in the reference frame of the Earth-Sun system. Image: JPL

Because of its orbital inclination of 10.739° to the ecliptic, 2002 AA₂₉ is not always forced by the Earth on its horseshoe orbit however but can sometimes slip out of this pattern. It is then caught for a while in the neighbourhood of the Earth. This will next happen in about 600 years i.e. in 26th century. It will then stay within the small gap in the Earth’s orbit which it does not reach in its previous horseshoe orbit, and will be no further than 0.2 astronomical units (30 million km) away from the Earth. There it will slowly circle the Earth almost like a second moon, although it takes one year for a circuit. After 45 years it finally switches back into the horseshoe orbit, until it again stays near the Earth for 45 years around the year 3750 and again in 6400. In these phases in which it stays outside its horseshoe orbit it oscillates in the narrow region along the Earth’s orbit where it is caught, moving back and forth in 15 years. Because it is not bound to the Earth like the Moon but is mainly under the gravitational influence of the Sun, it belongs to the bodies called quasi-satellites. This is somewhat analogous to two cars travelling side by side at the same speed and repeatedly overtaking one another but which are however not attached to each other. Orbital calculations show that 2002 AA₂₉ was in this quasi-satellite orbit for 45 years from about 520 A.D. but because of its tiny size was too dim to have been seen. It switches approximately cyclically between the two orbital forms, but always stays for 45 years in the quasi-satellite orbit. Outside the time frame from about 520-6500 A.D. the calculated orbits become chaotic i.e. not predictable, and thus for periods outside this time frame no exact statements can be made.^[2] 2002 AA₂₉ was the first known heavenly body that switches between horseshoe and quasi-satellite orbits.

Physical nature[link]

Brightness and size[link]

Relatively little is known about 2002 AA₂₉ itself. With a size of about 50 to 110 metres it is very small, on account of which it is seen from the Earth as a small point even with large telescopes, and can only be observed using highly sensitive CCD cameras. At the time of its closest approach on 8 January 2003 it had an apparent brightness in the visible region of magnitude 20.4.

So far nothing concrete is known about the composition of 2002 AA₂₉. Because of its nearness to the Sun, it cannot however consist of volatile substances such as water ice, since these would evaporate or sublime; one can clearly observe this happening to a comet as this forms the visible tail. Presumably it will have a dark, carbon-bearing or somewhat lighter silicate-rich surface; in the former case the albedo would be around 0.05, in the latter somewhat higher at 0.15 to 0.25. It is due to this uncertainty that the figures for its diameter cover such a wide range.

A further uncertainty arises from radar echo measurements at the Arecibo Radio Telescope, which could only pick up an unexpectedly weak radar echo, implying that 2002 AA₂₉ is either smaller than estimated or reflects radio waves only weakly. In the former case it would have to have an unusually high albedo.^[3] This would be evidence in support of the speculation that it, or at least the material of which it is composed, is different from most other asteroids so far discovered on near-Earth orbits, or represents a fragment thrown off by the collision of a medium-sized asteroid with the Earth or the Moon.^[1]

Rotational period[link]

Using radar echo measurements at the Arecibo radio telescope the rotational period of 2002 AA₂₉ could be determined. In this radar astronomy procedure radio waves of known wavelength are emitted from a radio telescope aimed at an asteroid. There they are reflected, and because of the Doppler effect the part of the surface that is moving towards the observer (because of the asteroid's rotation) shortens the wavelength of the reflected waves, whilst the other part which is turning away from the observer lengthens the reflected wavelength. As a result the wavelength of the reflected waves is “smeared out”. The extent of the wavelength smearing and the diameter of the asteroid allow the rotational period to be narrowed down. 33 minutes is thus calculated as the upper limit of the rotational period for 2002 AA₂₉; it probably rotates more quickly. This rapid rotation together with the small diameter and therefore low mass leads to some interesting conclusions:

• The asteroid rotates so quickly that the centrifugal force on its surface exceeds its gravitational pull. It is therefore under tension and so cannot be composed of an agglomeration of loosely-bound debris or of fragments circling each other – as is supposed for several other asteroids and for example has been determined for the asteroid (69230) Hermes. Instead the body must be made of a single relatively strong block of rock or of pieces baked together. However, its tensile strength is probably considerably lower than terrestrial rock and the asteroid also very porous.^[3]

• 2002 AA₂₉ cannot possibly have been built up from individual small pieces, as these would be thrown apart by the rapid rotation. Therefore it must be a fragment blown off in the collision of two heavenly bodies. J. Richard Gott and Edward Belbruno from Princeton University have speculated that 2002 AA₂₉ might have formed together with Earth and Theia, the postulated planet that, according to the giant impact hypothesis, collided with Earth in its early history.

Outlook[link]

Because its orbit is very similar to the Earth’s, the asteroid is relatively easily reachable by space probes. 2002 AA₂₉ would therefore be a suitable object of study for more precise research into the structure and formation of asteroids and the evolution of their orbits around the Sun. Meanwhile further co-orbital companions of the Earth of this type on horseshoe orbits or on orbits as quasi-satellites have already been found, such as the quasi-satellite 2003 YN₁₀₇. Furthermore it is assumed that there are small Trojan companions of the Earth with diameters in the region of 100 metres located at the L4 and L5 Lagrangian points of the Earth-Sun system.

Related objects[link]

• 6Q0B44E
• 2006 RH₁₂₀
• 2003 YN₁₀₇ – quasi-satellite of Earth
• 2010 TK₇ – Trojan co-orbital companion of Earth

See also[link]

• Natural satellite
• Quasi-satellite
• List of asteroids
• Naming of Asteroids

References[link]

4. M. Connors, P. Chodas, S. Mikkola, P. Wiegert, C. Veillet, K. Innanen: Discovery of an asteroid and quasi-satellite in an Earth-like horseshoe orbit. in: Meteoritics & Planetary Science. Allen Press, Lawrence Kan 37.2002, 10, 1435–1441. ISSN 1086-9379 (PDF)

5. Tilmann Althaus: Ein zweiter Begleiter des Blauen Planeten. in: Sterne und Weltraum. Spektrum der Wiss., Heidelberg 42.2003, 2, S. 22–24. ISSN 0039-1263

External links[link]

Articles[link]

• MPEC 2003-A17
• Earth coorbital asteroid 2002 AA₂₉
• Research paper describing horseshoe orbits. Recommend starting at page 105!

Databases[link]

• Orbital data for 2002 AA₂₉ from the MPEC database
• Physical data for 2002 AA₂₉ from the EARN Database
• Asteroid Orbital Elements Database of the Lowell Observatory

Wikimedia Commons has media related to: 2002 AA29

Wikimedia Commons has media related to: 2002

2002 (MMII) was a common year that started on a Tuesday. In the Gregorian calendar, it was the 2002nd year of Anno Domini, the 2nd year of the 3rd millennium and of the 21st century, and the 3rd of the 2000s decade. 2002 was a palindrome year. By coincidence, the last palindrome year (1991) was also a common year starting on Tuesday. The next time this will happen is between 5995 and 6006.

The year 2002 is designated the:

• International Year of Ecotourism and Mountains
• Year of the Outback in Australia
• National Science Year in the United Kingdom
• Autism Awareness Year in the United Kingdom

Events[link]

January[link]

• January 1
  • The Open Skies mutual surveillance treaty, initially signed in 1992, officially enters into force.
  • Euro notes and coins are introduced in France, Spain, Germany, Italy, Portugal, Greece, Finland, Luxembourg, Belgium, Austria, Ireland and the Netherlands.
• January 8 – The No Child Left Behind Act is signed into law by U.S. President George W. Bush.
• January 9 The United States Department of Justice announces it will pursue a criminal investigation of Enron.
• January 10 – Enrique Bolaños begins his 5-year term as President of the Republic of Nicaragua.
• January 14 – The asylum case of Adelaide Abankwah is heard in New York.
• January 16 – The UN Security Council unanimously establishes an arms embargo and freezes the assets of Osama bin Laden, Al-Qaeda, and the Taliban.
• January 17 – The eruption of Mount Nyiragongo in the Democratic Republic of the Congo displaces an estimated 400,000 people.
• January 23 – Wall Street Journal reporter Daniel Pearl is kidnapped in Pakistan, accused of being a CIA agent by his captors.
• January 27 – Several explosions at a military dump in Lagos, Nigeria kill more than 1,000.^{Confirmation needed}
• January 31 – A large section of the Antarctic Larsen Ice Shelf begins disintegrating, consuming about 3,250 km (2,020 mi) over 35 days.

February[link]

• February 1 – Kidnapped Wall Street Journal reporter Daniel Pearl is murdered in Karachi, Pakistan.
• February 3 – Costa Rica holds presidential and congressional elections.
• February 6 - King George VI's 50th Anniversary of his Death in 1952
• February 8–February 24 – The 2002 Winter Olympics are held in Salt Lake City, Utah.
• February 9 - Elizabeth II's sister Princess Margaret, Countess of Snowdon dies in her sleep aged 71 after suffering a major stroke.
• February 12
  • The trial of former Yugoslav President Slobodan Milošević begins at the United Nations war crimes tribunal in The Hague.
  • The U.S. Secretary of Energy makes the decision that Yucca Mountain is suitable to be the United States' nuclear repository.
• February 13 – Elizabeth II gives former New York City mayor Rudolph Giuliani an honorary knighthood.
• February 15 - The funeral of Princess Margaret, Countess of Snowdon takes place on the 50th anniversary of her father's funeral.

Artists concept of the 2001 Mars Odyssey Spacecraft

• February 19 – NASA's Mars Odyssey space probe begins to map the surface of Mars using its thermal emission imaging system.
• February 20 – In Reqa Al-Gharbiya, Egypt, a fire on a train injures over 65 and kills at least 370.
• February 22
  • Robert William Pickton; the most prolific serial killer in Canadian history is arrested and charged with the first two (of twenty-seven) counts of first-degree murder.
  • Angolan political and rebel leader Jonas Savimbi is killed in a military ambush.
  • A Spanish-facilitated ceasefire begins in Sri Lanka.
• February 23 – FARC kidnaps Íngrid Betancourt in Colombia while she campaigns for the presidency.
• February 27 – A series of riots leaves hundreds dead, after 59 Hindu pilgrims die aboard a train burned by a Muslim mob in Godhra, India.
• February 28
  • The ex-currencies of all euro-using nations cease to be legal tender in the European Union.
  • Gujarat communal riots begin, wherein the Gulbarg Society massacre takes place in Ahmedabad, in which 69 people were burnt alive or killed.

March[link]

Hubble Space Telescope after servicing by the crew of STS-109

• March 1
  • U.S. invasion of Afghanistan: In eastern Afghanistan, Operation Anaconda begins.
  • Continuing violence in Ahmedabad, India kills 28; police shoot and kill 5 rioters.
  • The Envisat environmental satellite successfully reaches an orbit 800 km above the Earth using an Ariane 5 on its 11th launch, carrying the heaviest payload to date at 8,500 kg.
  • STS-109: Space Shuttle Columbia flies the Hubble Space Telescope service mission, its last before STS-107.
• March 3 – São Tomé and Príncipe hold legislative elections.
• March 4 – Ansett Australia, one of the oldest airlines in the world and the second largest in Australia, ceases operation after collapsing financially. This event also marks the largest job loss in Australian history.
• March 6 – France agrees to return the remains of Saartjie Baartman to South Africa.
• March 12 – In Houston, Texas, Andrea Yates is found guilty of drowning her 5 children on June 20, 2001. She is later sentenced to life in prison.
• March 14
  • 125 vehicles are involved in a massive pile up on Interstate 75 in Ringgold, Georgia.
  • Economic Community of West African States (ECOWAS) Parliament established.
• March 17
  • Portugal holds parliamentary elections.
  • In Islamabad, Pakistan, the International Protestant Church attack occurs.
• March 19 – US war in Afghanistan: Operation Anaconda ends (started on March 1) after killing 500 Taliban and al Qaeda fighters, with 11 allied troop fatalities.
• March 21 – In Pakistan, Ahmed Omar Saeed Sheikh and 3 others are charged with the kidnapping and killing of Wall Street Journal reporter Daniel Pearl.
• March 24 – The 74th Academy Awards, hosted by Whoopi Goldberg, are held at the Kodak Theatre in Hollywood, California with the film A Beautiful Mind winning Best Picture.
• March 27 – A Palestinian suicide bomber kills 30 Israeli civilians and injures 140 others at the Park Hotel in Netanya, triggering Operation Defensive Shield, a large-scale counter-terrorist Israeli military incursion into the West Bank, two days later.

April[link]

• April 2 – Israeli forces besiege the Church of the Nativity in Bethlehem, when militants take shelter there.
• April 9 – The funeral of Queen Elizabeth The Queen Mother takes place in Westminster Abbey, London.
• April 11 – April 14 – A military coup d'état against the leftist Venezuelan President Hugo Chávez fails.
• April 15 – An Air China Boeing 767-200 crashes into a hillside during heavy rain and fog near Busan, South Korea, killing 128.
• April 17 – Four Canadian infantrymen are killed in Afghanistan by friendly fire from 2 US F-16s.
• April 18 – The discovery of a new insect order, Mantophasmatodea, is announced.
• April 21 – French presidential election, 2002: The first round results in a runoff between Jacques Chirac and the leader of the main French far-right party, Jean-Marie Le Pen.
• April 22 – At a special session of the Organisation for the Prohibition of Chemical Weapons, Director-General Jose Bustani is fired.
• April 25 – Soyuz TM-34: South African Mark Shuttleworth blasts off from the Baikonur Cosmodrome; he had paid £15 million for the trip.
• April 27 – The Laughlin, Nevada River Run Riot kills 3.

May[link]

May 20: Flag of East Timor

• May 5 – In the second round of the French presidential election Jacques Chirac is reelected.
• May 6 – In the Netherlands, politician Pim Fortuyn is assassinated.
• May 9 – A 38-day stand-off in the Church of the Nativity in Bethlehem ends, when the Palestinians inside agree to have 13 suspected militants among them deported to several different countries.
  • In Kaspiysk, Russia, a remote-control bomb explodes during a holiday parade, killing 43 and injuring at least 130.
• May 8 – Feyenoord Rotterdam wins the UEFA Final Cup with 3-2 from Borussia Dortmund.
• May 10 – FBI agent Robert Hanssen is sentenced to life imprisonment without the possibility of parole for selling American secrets to Moscow for $1.4 million in cash and diamonds.
• May 12
  • Former U.S. President Jimmy Carter arrives in Cuba for a 5-day visit with Fidel Castro, becoming the first U.S. President, in or out of office, to visit the island since Castro's 1959 revolution.
  • The Russian Shuttle Buran is destroyed in the Buran hangar collapse, killing 8 workers.
• May 17 – In Ireland, The Fianna Fáil-Progressive Democrats coalition is re-elected. It is the first government to be re-elected since 1969.
• May 20 – East Timor regains its independence.
• May 21 – The US State Department releases a report naming 7 state sponsors of terrorism: Iran, Iraq, Cuba, Libya, North Korea, Sudan, and Syria.
• May 22 – 16th Street Baptist Church bombing: A jury in Birmingham, Alabama, convicts former Ku Klux Klan member Bobby Frank Cherry of the 1963 murders of 4 girls.
• May 25
  • Estonia hosts the first Eurovision Song Contest in a former Soviet republic.
  • China Airlines Flight 611 disintegrates near the Penghu Islands at Taiwan Strait, killing all 225 people on board.
• May 26
  • The Mars Odyssey finds signs of large water ice deposits on the planet Mars.
  • A barge collides with the Interstate 40 bridge across the Arkansas River in eastern Oklahoma, killing 14.
• May 31 – June 30 – the 2002 FIFA World Cup is held in South Korea and Japan

June[link]

• June 3 – The "Party in the Palace" takes place at Buckingham Palace, London, for Elizabeth II's Golden Jubilee celebrations.
• June 4 – The planetoid Quaoar is discovered orbiting the Sun in the Kuiper belt.
• June 5 – Fourteen-year-old Elizabeth Smart is kidnapped from her bedroom at knifepoint.
• June 6 – Eastern Mediterranean Event: An object with an estimated diameter of 10 meters collides with Earth, over the Mediterranean Sea, and detonates in mid-air.
• June 8 – Serena Williams defeats her sister Venus Williams in straight sets to win the 2002 French Open.
• June 10
  • An annular solar eclipse occurs.
  • The first direct electronic communication experiment between the nervous systems of 2 humans, is carried out by Kevin Warwick in the United Kingdom.
• June 11 – Antonio Meucci is recognized as the first inventor of the telephone by the United States Congress.
• June 14 – In Karachi, Pakistan, a car bomb in front of the U.S. Consulate kills 12 Pakistanis and injures 50.
• June 15 – Near Earth Asteroid 2002 MN misses the planet by 75,000 miles (121,000 km), about 1/3 the distance to the moon.
• June 24 – The Igandu train disaster in Dodoma Region, Tanzania, kills 281 people in the worst rail accident in African history.
• June 30 – Brazil wins its fifth FIFA World Cup, defeating Germany in the final.

July[link]

• July 1
  • The International Criminal Court is established to prosecute individuals for genocide, crimes against humanity, war crimes, and the crime of aggression. Crimes committed on or after this date may be prosecuted by the court.
  • A Russian passenger jet and a cargo plane collide over the town of Überlingen, Germany; 72 are killed (see Bashkirian Airlines Flight 2937).
• July 9 – The Organization of African Unity is disbanded and replaced by the African Union.
• July 10
  • At a Sotheby's auction, Peter Paul Rubens' painting "The Massacre of the Innocents" (first version) is sold for £49.5million (US$76.2 million) to Kenneth Thomson, 2nd Baron Thomson of Fleet.
  • A helicopter crash in Cyprus kills the head of the Cyprus National Guard, Lt. General Evangelos Florakis.
• July 14 – During Bastille Day celebrations, Jacques Chirac escapes an assassination attempt.
• July 15 – In Washington, D.C., "American Taliban" John Walker Lindh pleads guilty to aiding the enemy and possession of explosives during the commission of a felony; Lindh agrees to serve 10 years in prison for each charge.
• July 19 – Hail kills 25 and injures hundreds in the Chinese province of Henan.
• July 21 – Telecommunications giant WorldCom files for Chapter 11 bankruptcy protection (the largest such filing in United States history).
• July 27
  • A Sukhoi Su-27 fighter crashes at an air show in Ukraine, killing 77 and injuring more than 100, making it the worst air show disaster in history (see Sknyliv airshow disaster).
  • Helen Clark, leader of the New Zealand Labour Party, is re-elected in a landslide victory.

August[link]

• August – The 2002 European floods ravage Central Europe.
• August 14 – DPC Enterprises Chlorine Release, Festus, Missouri (USA) ^[1]

September[link]

Gerhard Schröder

• September 2 – The United Nations World Summit on Sustainable Development, successor of the 1972 Conference on the Human Environment, 1983 World Commission on Environment and Development, and the 1992 Conference on Environment and Development, opens.
• September 5 – A car bomb kills at least 30 people in Afghanistan, and an apparent assassination attempt on Afghan President Hamid Karzai fails the same day.
• September 9 – Judit Polgar beats Garry Kasparov at a game of speed chess.
• September 10 – Switzerland joins the United Nations.
• September 11 – The World Summit on Sustainable Development comes to a close.
• September 15 – The Swedish parliamentary election, 2002 leaves Prime Minister Göran Persson and the Social Democrats in power.
• September 19 – Civil war starts in Côte d'Ivoire.
• September 20 – The Kolka-Karmadon rock ice slide occurs.
• September 22 – The German federal election leaves Chancellor Gerhard Schröder, his Social Democrats and the Greens in power.
• September 25 – The Vitim event, a possible bolide impact, occurs in Siberia, Russia.
• September 26 – The Senegalese passenger ferry Joola capsizes in a storm off the coast of Gambia; 1,863 are killed.

October[link]

• October 2
  • The Congress of the United States passes a joint resolution, which authorizes the President to use the United States Armed Forces as he deems necessary and appropriate, against Iraq.
  • The Beltway sniper attacks begin with 5 shootings in Montgomery County, Maryland.
• October 7 – The discovery of Quaoar is announced.
• October 9 – The Dot-com bubble bear market reaches bottom, when the Dow Jones Industrial Average slips below 7,200.
• October 11 – Myyrmanni bombing: A lone bomber explodes a home-made bomb in the Myyrmanni shopping mall north of Helsinki, Finland; the casualties include himself.
• October 12 – Terrorists detonate bombs in 2 nightclubs in Kuta, Bali, killing 202 and injuring over 300.
• October 16 – Iraq War Resolution is authorized by a majority of the U.S. Congress.
• October 21 – 9 of 13 DNS root servers are disabled in a DDoS attack.
• October 22 – 25 – Chechen rebels take control of the theatre Nord-Ost in Moscow and hold the audience hostage.
• October 24 – The Beltway snipers, John Allen Muhammad and Lee Boyd Malvo, are arrested.
• October 25 – U.S. Senator Paul Wellstone, his family, and his staff are killed in a plane accident at Eveleth, Minnesota.
• October 27 – Luiz Inácio Lula da Silva is elected President of Brazil.

November[link]

The Department of Homeland Security is formed in response to terrorist concerns in the United States.

• November 5 – The U.S. Republican Party maintains control of the House of Representatives and gains control of the United States Senate.
• November 6 – The U.S. Federal Reserve System drops its primary discount rate by 50 basis points to 0.75%, putting the real interest rate solidly below the inflation rate.
• November 7 – Iran bans the advertising of United States products.
• November 8 – Iraq disarmament crisis: The United Nations Security Council unanimously approves UN Security Council Resolution 1441, forcing Saddam Hussein to disarm or face "serious consequences".
• November 13
  • Iraq disarmament crisis: Iraq agrees to the terms of UN Security Council Resolution 1441.
  • The oil tanker Prestige sinks off the Galician coast, causing a huge oil spill.
• November 14 – Argentina defaults on a US $805 million World Bank loan payment.
• November 15 – Hu Jintao becomes General Secretary of the Communist Party of China.
• November 16 – A Campaign against Climate Change march takes place in London from Lincoln's Inn Fields, past Esso offices to the United States Embassy.
• November 18 – Iraq disarmament crisis: United Nations weapons inspectors led by Hans Blix arrive in Iraq.
• November 21 – At the NATO Summit in Prague, Bulgaria, Estonia, Latvia, Lithuania, Romania, Slovakia, and Slovenia are invited to join the organization.
• November 22 – In Nigeria, more than 100 are killed at an attack aimed at the Miss World contestants.
• November 25 – U.S. President George W. Bush signs the Homeland Security Act into law, establishing the Department of Homeland Security, in the largest U.S. government reorganization since the creation of the Department of Defense in 1947.
• November 26 – Legislation by the European Court of Human Rights and Law Lords, ruling in favour of convicted murderer Anthony Anderson, ends the right of the Home Secretary to set minimum terms for convicted murderers.

December[link]

• December 7 – As required by the recently passed U.N. resolution, Iraq files a 12,000 page weapons declaration with the U.N. Security Council.
• December 9 – United Airlines, the second largest airline in the world, files for bankruptcy.
• December 10 – The High Court of Australia hands down its judgement in the Internet defamation dispute in the case of Gutnick v Dow Jones.
• December 12 – Hans Enoksen is elected Prime Minister of Greenland.
• December 27 – A suicide truck-bomb attack destroys the headquarters of Chechnya's Moscow-backed government, killing 72.
• December 29 – The Communist New People's Army blows up a bust of Ferdinand Marcos in Benguet, Philippines.
• December 30 – An eruption on the volcanic island Stromboli off the coast of Sicily causes a flank failure and tsunami. The island is later evacuated.

Date unknown[link]

• Population Division of the United Nations calculate that 40 million people around the world are infected with HIV.

Births[link]

• February 5 – Davis Cleveland, American child actor
• July 22 – Prince Felix of Denmark, Prince of Denmark
• October 6 – Cleopatra Stratan, Moldovan child singer

Deaths[link]

January[link]

Cyrus Vance

• January 3 – Freddy Heineken, Dutch-born beer magnate (b. 1923)
• January 8
  • Alexander Prokhorov, Russian physicist, Nobel Prize laureate (b. 1916)
  • Dave Thomas, American fast food entrepreneur (Wendy's) (b. 1932)
• January 12
  • Stanley Unwin, South African comedian (b. 1911)
  • Cyrus Vance, American politician, 59th United States Secretary of State (b. 1917)
• January 15 – Eugène Brands, Dutch painter (b. 1913)
• January 16
  • Michael Anthony Bilandic, Mayor of Chicago (b. 1923)
  • Bobo Olson, American boxer (b. 1928)
• January 17
  • Queenie Leonard, British singer and actress (b. 1905)
  • Camilo José Cela, Spanish writer (b. 1916)
• January 22
  • Jack Shea, American double-Gold medalist in skating speedly (b. 1910)
  • Peggy Lee, American singer and actress (b. 1920)
• January 23
  • Pierre Bourdieu, French sociologist (b. 1930)
  • Robert Nozick, American philosopher (b. 1938)
• January 28 – Astrid Lindgren, Swedish children's book author (b. 1907)

February[link]

Princess Margaret, Countess of Snowdon

• February 6 – Max Perutz, Austrian-born molecular biologist, recipient of the Nobel Prize in Chemistry (b. 1914)
• February 8
  • Joachim Hoffmann, German historian (b. 1930)
  • Thomaz Soares da Silva, Brazilian football player (b. 1921)
• February 9 – Princess Margaret, Countess of Snowdon (b. 1930)
• February 10 – Traudl Junge, German private secretary of Adolf Hitler (b. 1920)
• February 12 – John Eriksen, Danish football player (b. 1957)
• February 13 – Waylon Jennings, American country music singer (b. 1937)
• February 14 – Nándor Hidegkuti, Hungarian footballer (b. 1922)
• February 15
  • Howard K. Smith, American television journalist (ABC News) (b. 1914)
  • Kevin Smith, New Zealand actor (b. 1963)
• February 16 – Walter Winterbottom, English football manager (b. 1913)
• February 19 – Virginia Hamilton, American writer (b. 1936)
• February 22
  • Chuck Jones, American animator (b. 1912)
  • Jonas Savimbi, Angolan rebel and political leader (b. 1934)
• February 24 – Leo Ornstein, American composer and pianist (b. 1892)
• February 27 – Spike Milligan, British comedian, writer, and poet (b. 1918)
• February 28 – Helmut Zacharias, German violinist (b. 1920)

March[link]

Queen Elizabeth The Queen Mother

• March 11 – James Tobin, American economist, Nobel Prize laureate (b. 1918)
• March 12 – Spyros Kyprianou, former President of Cyprus (b. 1932)
• March 20 – Ibn Al-Khattab, Saudi guerilla (b. 1969)
• March 24 – César Milstein, Argentine scientist, recipient of the Nobel Prize in Physiology or Medicine (b. 1927)
• March 27
  • Milton Berle, American comedian and actor (b. 1908)
  • Dudley Moore, British pianist, comedian, and actor (b. 1935)
  • Billy Wilder, Polish-American film screenwriter and director (b. 1906)
• March 29 – Rico Yan, Filipino Actor (b. 1975)
• March 30 – Queen Elizabeth The Queen Mother (née Elizabeth Bowes-Lyon), queen consort of George VI and mother of Elizabeth II (b. 1900)

April[link]

• April 5 – Layne Staley, American singer (b. 1967)
• April 8 – María Félix, Mexican actress (b. 1914)
• April 9 – Leopold Vietoris, Austrian mathematician (b. 1891)
• April 15 – Byron White, American athlete and Supreme Court Justice (b. 1917)
• April 16
  • Franz Krienbühl, Swiss speed skater (b. 1929)
  • Robert Urich, American actor (b. 1946)
• April 18
  • Thor Heyerdahl, Norwegian explorer (b. 1914)
  • Wahoo McDaniel, American football player and professional wrestler (b. 1938)
• April 22 – Linda Lovelace, American pornographic actress (b. 1949)
• April 25 – Lisa Lopes, American rapper; one-third of the multi-platinum girl group TLC (b. 1971)
• April 27
  • George Alec Effinger, American author (b. 1947)
  • Baron Hans Heinrich Thyssen-Bornemisza, Swiss industrialist and art collector (b. 1921)
  • Ruth Handler, American toy manufacturer (b. 1916)
• April 28 – Lou Thesz, American professional wrestler (b. 1916)

May[link]

Pim Fortuyn

• May 5 – Hugo Banzer, Bolivian politician, 62nd and 75th President of Bolivia (b. 1926)
• May 6 – Pim Fortuyn, Dutch politician and professor (b. 1948)
• May 11 – Joseph Bonanno, Italian-born gangster (b. 1905)
• May 13 – Valeri Lobanovsky, Ukrainian football manager (b. 1939)
• May 18 – Davey Boy Smith, British professional wrestler (b. 1962)
• May 19 – John Gorton, Australian politician, 19th Prime Minister of Australia (b. 1911)
• May 20 – Stephen Jay Gould, American paleontologist and author (b. 1941)
• May 21 – Niki de Saint Phalle, French artist (b. 1930)
• May 23 – Sam Snead, American golfer (b. 1912)
• May 26 – Mamo Wolde, Ethiopian runner (b. 1932)
• May 28 – Jean Berger, German-American composer (b. 1909)

June[link]

Fernando Belaúnde Terry

• June 2 – Hansie Cronje, South African cricketer and captain of the South African national cricket team in the 1990s.(b. 1969)
• June 4 – Fernando Belaúnde Terry, Peruvian politician, 85th and 88th President of Peru (b. 1912)
• June 5 – Dee Dee Ramone, American bassist (b. 1951)
• June 6 – Hans Janmaat, Dutch politician (b. 1934)
• June 7 – Lilian, Princess of Réthy, Belgian princess (b. 1916)
• June 10 – John Gotti, American gangster (b. 1940)
• June 17 – Fritz Walter, German footballer (b. 1920)
• June 24 – Pierre Werner, Luxembourgian politician, 19th and 21st Prime Minister of Luxembourg (b. 1913)
• June 26 – Arnold Brown, English General of The Salvation Army (b. 1913)
• June 27 – John Entwistle, English bassist (b. 1944)
• June 29 – Rosemary Clooney, American singer and actress (b. 1928)
• June 30 – Chico Xavier, Brazilian medium (b. 1910)

July[link]

Joaquín Balaguer

Joseph Luns

• July 5
  • Benjamin O. Davis Jr., American general (b. 1912)
  • Katy Jurado, Mexican actress (b. 1924)
  • Ted Williams, American baseball player (b. 1918)
• July 6
  • Dhirubhai Ambani, Indian businessman (b. 1932)
  • John Frankenheimer, American film director (b. 1930)
    • Abdul Qadir, Vice president of Afghanistan (b. 1951)
• July 9
  • Mayo Kaan, bodybuilder (b. 1914)
  • Rod Steiger, American actor (b. 1925)
• July 10 – Evangelos Florakis, Greek military officer (b. 1943)
• July 13 – Yousuf Karsh, Turkish-born photographer (b. 1908)
• July 14 – Joaquín Balaguer, Dominican politician, 41st, 45th and 49th President of the Dominican Republic (b. 1906)
• July 16 – John Cocke, American computer scientist (b. 1925)
• July 17 – Joseph Luns, Dutch politician and diplomat, 5th Secretary General of NATO (b. 1911)
• July 19 – Alan Lomax, American folklorist and musicologist (b. 1915)
• July 21 - Antti Koivumäki, Finnish poet and keyboardist (Aavikko) (b. 1976)
• July 23 – Chaim Potok, American author and rabbi (b. 1929)
• July 25 – Abdur Rahman Badawi, Egyptian philosopher (b. 1917)
• July 28 – Archer John Porter Martin, English chemist, Nobel Prize laureate (b. 1910)

August[link]

Edsger W. Dijkstra

• August 4 – Carmen Silvera, British actress (b. 1922)
• August 5
  • Chick Hearn, American SportsCaster (b. 1916)
  • Franco Lucentini, Italian writer (b. 1920)
• August 6 – Edsger W. Dijkstra, Dutch computer scientist (b. 1930)
• August 11 – Galen Rowell, American photographer, writer, and climber (b. 1940)
• August 14 – Dave Williams, American singer (b. 1972)
• August 16 – Abu Nidal, Paleiostinian militant (b. 1937)
• August 31
  • Lionel Hampton, American musician (b. 1908)
  • George Porter, English chemist, Nobel Prize laureate (b. 1920)

September[link]

• September 11 – Kim Hunter, American actress (b. 1922)
• September 18 – Bob Hayes, American athlete (b. 1942)
• September 19
  • Robert Guéï, Ivorian military ruler (b. 1941)
  • Duncan Hallas, prominent member of the Trotskyist movement in Great Britain (b. 1925)
• September 21 – Robert Lull Forward, American author and physicist (b. 1932)
• September 22 – James Miller, known as the 'Fan Man' (b. 1963)

October[link]

Claus van Amsberg

• October 6 – Claus van Amsberg, German born Prince Consort of the Netherlands (b. 1926)
• October 9
  • Sopubek Begaliev, Soviet-era economist and politician (b. 1931)
  • Aileen Wuornos, American serial killer (b. 1956)
• October 12 – Ray Conniff, American musician and bandleader (b. 1916)
• October 13 – Stephen Ambrose, American historian and biographer (b. 1936)
• October 18 – Nikolai Rukavishnikov, Russian cosmonaut (b. 1932)
• October 25 – Richard Harris, Irish actor (b. 1930)
• October 30 – Jam-Master Jay, American Hip-Hop DJ (b. 1965)

November[link]

Abba Eban

• November 2 – Charles Sheffield, English author and physicist (b. 1935)
• November 9 – Merlin Santana, American actor (b. 1976)
• November 12 – Károly Doncsecz, Slovenian potter (b. 1918)
• November 15 – Myra Hindley, English murderer (b. 1942)
• November 17 – Abba Eban, Israeli politician and diplomat, 3rd Minister of Foreign Affairs (b. 1915)
• November 18 – James Coburn, American actor (b. 1928)
• November 19 – Max Reinhardt, British publisher (b. 1915)
• November 22 – Parley Baer, American actor (b. 1914)
• November 24 – John Rawls, American political theorist (b. 1921)

December[link]

Joe Strummer

• December 3 – Glenn Quinn, Irish actor (b. 1970)
• December 5 – Ne Win, Burmese military commander (b. 1911)
• December 18 – Ray Hnatyshyn, Governor General of Canada (b. 1934)
• December 22
  • Desmond Hoyte, Guyanese politician, 3rd Prime Minister of Guyana and 4th President of Guyana (b. 1929)
  • Joe Strummer, British musician (b. 1952)

Nobel Prizes[link]

Daniel Kahneman

• Peace – Jimmy Carter
• Literature – Imre Kertész
• Chemistry – John B. Fenn and Koichi Tanaka, Kurt Wüthrich
• Physics – Raymond Davis Jr. and Masatoshi Koshiba, Riccardo Giacconi
• Physiology or Medicine – Sydney Brenner, H. Robert Horvitz, and John E. Sulston
• Bank of Sweden Prize in Economic Sciences in Memory of Alfred Nobel – Daniel Kahneman and Vernon L. Smith

Fields Medalists[link]

• Laurent Lafforgue, Vladimir Voevodsky

In fiction[link]

• The events of First Among Sequels by Jasper Fforde take place in an alternate-reality 2002
• In the comic book series Y: The Last Man, on July 12, 2002 a mysterious plague kills all living creatures with a Y chromosome on the planet.
• The West Wing: On November 5, Democratic President Josiah Bartlet of New Hampshire defeats Republican Governor Robert Ritchie of Florida in his reelection bid following the 2002 US presidential election.
• The events of Resident Evil: Dead Aim take place on September 23.

References[link]

External links[link]

2000s portal

• 2002 Year-End Google Zeitgeist – Google's Yearly List of Major Events and Top Searches for 2002
• Top Stories of 2002 - CNN
• Year in Review - Netscape

3753 Cruithne

Discovery
Discovered by	Duncan Waldron
Discovery date	October 10, 1986
Designations
Named after	Cruthin
Alternate name(s)	1983 UH; 1986 TO
Minor planet category	Near-Earth asteroid, Venus-crosser asteroid, Mars-crosser asteroid
Orbital characteristics[1]
Epoch June 18, 2009 (JD 2455000.5)
Aphelion	1.51 AU (226.105 Gm)
Perihelion	0.484 AU (72.415 Gm)
Semi-major axis	0.998 AU (149.260 Gm)
Eccentricity	0.515
Orbital period	1.00 a (364.01 d)
Average orbital speed	27.73 km/s
Mean anomaly	170.36°
Inclination	19.81°
Longitude of ascending node	126.28°
Argument of perihelion	43.74°
Proper orbital elements
Physical characteristics
Dimensions	~5 km
Mass	1.3×1014 kg
Mean density	2 ? g/cm³
Equatorial surface gravity	0.0014 m/s²
Escape velocity	2.6 metres per second (8.5 ft/s)
Rotation period	27.44 hours[1]
Temperature	~ 273 K
Spectral type	?
Absolute magnitude (H)	15.1[1]

3753 Cruithne ( /ˈkrɪnjə/, from Old Irish [ˈkrɪθnɛ]; Modern [ˈkrɪhnʲə] or [ˈkrɪnʲə]) is an asteroid in orbit around the Sun in approximate 1:1 orbital resonance with the Earth. It is a periodic inclusion planetoid^{[What does this mean?]} orbiting the Sun in an apparent horseshoe orbit.^[2] It has been incorrectly called "Earth's second moon", but it is a quasi-satellite^[2], not a moon. Cruithne does not orbit Earth, and at times it is on the other side of the Sun.^[3] Its orbit takes it inwards towards the orbit of Mercury, and outside the orbit of Mars.^[3] Cruithne orbits the Sun in about 1 year, but it takes 770 years for the series to complete a horseshoe-shaped movement, with the Earth in the gap of the horseshoe.^[3]

The name Cruithne is from Old Irish, the Celtic term for the Picts, as well as the name of a people of eastern Ulster.

Discovery[link]

Cruithne was discovered on October 10, 1986, by Duncan Waldron on a photographic plate taken with the UK Schmidt Telescope at Siding Spring Observatory, Coonabarabran, Australia. The 1983 apparition (1983 UH) is credited to Giovanni de Sanctis and Richard M. West of the European Southern Observatory in Chile. It was not until 1997 that its unusual orbit was determined by Paul Wiegert and Kimmo Innanen, working at York University in Toronto, and Seppo Mikkola, working at the University of Turku in Finland.

The asteroid is named after the Cruithne or Cruthin, a people of early medieval Ireland mentioned in the Annals of Ulster.^[3]

Dimensions and orbit[link]

Cruithne and Earth seem to follow each other because of a 1:1 orbital resonance.

Cruithne appears to make a bean-shaped orbit from the perspective of Earth.

Cruithne's distance to Earth and the Sun plotted over 500 years (top) and 10 years (bottom).

Cruithne is approximately 5 kilometres (3.1 mi) in diameter, and its closest approach to Earth is approximately thirty times the separation between Earth and the Moon (12 Gm or twelve million kilometres). From 1994 through 2015, Cruithne makes its annual closest approach to Earth every November.^[4] Although Cruithne's orbit is not thought to be stable over the long term, calculations by Wiegert and Innanen showed that it has probably been synchronized with Earth's orbit for a long time. There is no danger of a collision with Earth for millions of years, if ever. Its orbital path and Earth's do not cross, and its orbital plane is currently tilted to that of the Earth by 19.8°. Cruithne, having a maximum near-Earth magnitude of +15.8, is fainter than Pluto and would require at least a 12.5-inch (320 mm) reflecting telescope to be seen.^[5][6]

Cruithne is in a normal elliptic orbit around the Sun. Its period of revolution around the Sun, approximately 364 days at present, is almost equal to that of the Earth. Because of this, Cruithne and Earth appear to "follow" each other in their paths around the Sun. This is why Cruithne is sometimes called "Earth's second moon".^[2] However, it does not orbit the Earth and is not a moon.^[7] In 2058, Cruithne will come within 0.09 AU (13.6 million kilometres) of Mars.^[4] Due to a high orbital eccentricity, Cruithne's distance from the Sun and orbital speed vary a lot more than the Earth's, so from the Earth's point of view Cruithne actually follows a kidney bean-shaped horseshoe orbit ahead of the Earth, taking slightly less than one year to complete a circuit of the "bean". Because it takes slightly less than a year, the Earth "falls behind" the bean a little more each year, and so from our point of view, the circuit is not quite closed, but rather like a spiral loop that moves slowly away from the Earth.

After many years, the Earth will have fallen so far behind that Cruithne will then actually be "catching up" on the Earth from "behind". When it eventually does catch up, Cruithne will make a series of annual close approaches to the Earth and gravitationally exchange orbital energy with Earth; this will alter Cruithne's orbit by a little over half a million kilometres—while Earth's orbit is altered by about 1.3 centimetres (0.51 in)—so that its period of revolution around the Sun will then become slightly more than a year. The kidney bean will then start to migrate away from the Earth again in the opposite direction – instead of the Earth "falling behind" the bean, the Earth is "pulling away from" the bean. The next such series of close approaches will be centred on the year 2292 – in July of that year, Cruithne will approach Earth to about 12,500,000 kilometres (7,800,000 mi).

After 380 to 390 years or so, the kidney-bean-shaped orbit approaches Earth again from the other side, and the Earth, once more, alters the orbit of Cruithne so that its period of revolution around the Sun is again slightly less than a year (this last happened with a series of close approaches centred on 1902, and will next happen with a series centered on 2676). The pattern then repeats itself.

Similar minor planets[link]

Figure 1. Plan showing possible orbits along gravitational contours (Not to scale)

More resonant near-Earth objects (NEOs) have since been discovered. These include 54509 YORP, (85770) 1998 UP₁, 2002 AA₂₉, and 2009 BD which exist in resonant orbits similar to Cruithne's. 2010 TK₇ is the first and so far only identified Earth trojan.

Other examples of natural bodies known to be in horseshoe orbits include Janus and Epimetheus, natural satellites of Saturn. The orbits these two moons follow around Saturn are much simpler than the one Cruithne follows, but operate along the same general principles.

Mars has four known co-orbital asteroids (5261 Eureka, 1999 UJ₇, 1998 VF₃₁, and 2007 NS₂, all at the Lagrangian points), and Jupiter has many (more than 1000 known objects, the Trojan asteroids); there are also other small co-orbital moons in the Saturnian system: Telesto and Calypso with Tethys, and Helene and Polydeuces with Dione. However, none of these follow horseshoe orbits.

Cruithne in popular culture[link]

Cruithne plays a major role in Steven Baxter's novel Manifold: Time, which was nominated for the Arthur C. Clarke science fiction award in 2000.

See also[link]

• 2006 RH₁₂₀
• 2010 SO₁₆
• Asteroids in fiction: Other asteroids, Asteroids in fiction: Colonization, and Asteroids in fiction: Mining
• Co-orbital configuration
• Earth's second moon
• Natural satellite
• Quasi-satellite

References[link]

Further reading[link]

• Wiegert, Paul A.; Innanen, Kimmo A.; Mikkola, Seppo (1997). "An asteroidal companion to the Earth". Nature 387 (6634): 685–686. DOI:10.1038/42662. 
• Meeus, Jean (2002). "Cruithne, an asteroid with a remarkable orbit". More Mathematical Astronomy Morsels. Richmond, Virginia: Willmann-Bell. ISBN 0-943396-74-3. 

External links[link]

• Paul Wiegert's page about Cruithne, with movies
• Java-applet based animations showing Cruithne's orbit
• A simulation of Cruithne's orbit with animation (Gravity Simulator)
• 3753 Cruithne at the JPL Small-Body Database

• Discovery · Orbit diagram · Orbital elements · Physical parameters

• Curious About Astronomy: Have astronomers discovered Earth's second moon?