Asteroides
•Download as PPS, PDF•
2 likes•1,095 views
Descripció dels principals asteroides del sistema solar
![1. Sistema Solar. 1.1. Tipus de cossos i de matèria. ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Recommended
More Related Content
What's hot
What's hot (20)
Viewers also liked
Viewers also liked (20)
Similar to Asteroides
Similar to Asteroides (20)
More from Albert Grau Gatell
More from Albert Grau Gatell (19)
Recently uploaded
Recently uploaded (10)
Asteroides
- 1. Fauna menor del Sistema Solar - 1: asteroides Seminari d’Astronomia I.E.S. Cid - València
- 3. 1.2. Repartiment de la massa del Sistema Solar. Sol: 99’8 % de la massa total del Sistema Solar. Júpiter: 0’14 % (71% de la massa planetària) Saturn: 0’04% (21%) Terra: 0’0004% (0’2%)
- 5. Nebulosa d’Orió: una zona amb intensa formació de sistemes estel·lars.
- 20. 6. Classes d’asteroides Asteroides primitius : - Interior metàl·lic. - Escorça rocosa. - Part intermèdia barrejada. (col·lisions provoquen diversitat de composicions dels fragments). Classes d’asteroides : Tipus C ( = carbonacis). Són més del 75% de tots els asteroides. Tipus S ( = silicis). Fe i Ni barrejats amb silicats de Fe. Són el 17% dels coneguts. Tipus M ( = metàl·lics). Fe i Ni purs. Tipus rars: P (vermellosos), D (molt foscos),...
- 22. 7.1. El Cinyell Principal La Llei de Titius-Bode. seqüència: 0 3 6 12 24 48 96 192 +4: 4 7 10 16 28 52 100 196 dist.real: 3’9 7’2 10 15’2 --- 52 95 192 planeta: Mer Ven Ter Mar --- Jup Sat Urà
- 24. Cinyell Principal: s’hi concentra la gran majoria d’asteroides. Densitat irregular: Buits de Kirkwood (ressonàncies). Famílies d’Hirayama (esmicolament de cossos anteriors). verd: asteroides roig: NEOs punt blau: troians quadrat blau: cometa
- 26. 7.2. Troians.
- 28. 8. Alguns asteroides notables 1 Ceres. 4 Vesta. 1998KY26. 2002NY40. 243 Ida i Dactyl. 4769 Castalia. 90 Antiope. 4179 Toutatis. 216 Kleopatra. 253 Mathilde. 2060 Chiron. 5154 Pholus.
- 29. 1 Ceres El el més voluminós i el primer descobert. Arrodonit; fa uns 1000 km de diàmetre. Conté més del 25% de la massa de tots els asteroides. Orbita el Sol en 4’6 anys. (N’hi ha poca més informació) 8.1. Els grans.
- 30. 4 Vesta Uns 500 km de diàmetre.
- 31. 1998 KY26 8.2. Els darrers.
- 32. 2001 KX76
- 33. 2002 NY40
- 34. 243 Ida … 8.3. Asteroides amb satèl·lits
- 35. … amb Dactyl
- 37. Any 2000: en realitat és un asteroide doble (dos rocs d’uns 80 km de llarg separats per 150 km). Orbiten a l’entorn del centre de masses cada 16’5 hores. Imatges del telescopi Keck, de Hawaii, amb tècniques d’òptica adaptativa). 90 Antiope : un vell conegut del Cinyell Principal. 8.4. Asteroides dobles.
- 38. 4769 Castalia 8.5. Formes estranyes .
- 39. 4769 Castalia
- 40. 4179 Toutatis
- 41. 216 Kleopatra
- 42. 216 Kleopatra
- 43. 253 Mathilde
- 44. 253 Mathilde
- 45. 8.6. Asteroides esdevinguts satèl·lits d’un planeta Els satèl·lits externs de Júpiter (ja en són més de 30!), Saturn, Urà i Neptú. Phobos i Deimos comparats amb Gaspra i Ida, a la mateixa escala.
- 46. Phobos
- 49. 9. Exploració dels asteroides. 9.1. Expedicions acomplertes. Galileo (de camí vers Júpiter). 1991 oct.: 951 Gaspra (del Cinyell Principal), sobrevol. 1993 ago.: 243 Ida (id.): sobrevol. NEAR. 1997 juny: 253 Mathilda (Cinyell Principal), sobrevol. 1998 des.: 433 Eros , falla posar-se en òrbita d’Eros. 2000 feb.: 433 Eros , en òrbita d’Eros; 14 feb.: hi aterra. Deep Space (propulsió iònica). 1999 jul.: 9969 Braille , sobrevol. Cassini (de camí vers Saturn). 2000 gen,: 2685 Masursky , sobrevol.
- 51. 9.2. Expedicions futures. Muses-C (japonesa). Portarà una mostra de 4660 Nereus el 2007. Rosetta (europea). Vers el cometa Wirtanen (l’assolirà el 2008). Farà flyby de 140 Siwa i de 4979 Otawara (el 2006). Dawk (USA). Òrbita a l’entorn de 4 Vesta (2010) i 1 Ceres (2014).
- 52. I la psicosi de l’impacte: Don Quijote , Earthguard 1 ,…!
- 53. 433 Eros des de la NEAR 9.3. Cita entre la sonda NEAR i l’asteroide 433 Eros .
- 54. 433 Eros
- 55. 433 Eros
- 56. 433 Eros
- 57. 433 Eros Sonda NEAR a 204 km de distància. Els menors detalls: 20 m. Cràter: 5 km d’ample. Gravetat: 1/1000 de la de la Terra (el cràter és saltable).
- 58. 433 Eros
- 59. 433 Eros A 50 km d’Eros. Ample: 1’3 km. Detalls: 4 m. 65 m
- 60. 433 Eros
- 61. 433 Eros
- 62. 433 Eros
- 63. 433 Eros
- 64. 433 Eros
- 65. 433 Eros
- 66. 433 Eros
- 67. 433 Eros
- 69. 433 Eros 12 metres
- 70. 433 Eros
- 72. 433 Eros
- 73. 433 Eros
- 75. 433 Eros
- 76. El cor d’Eros.
- 79. Asteroide 1998 WT24 : el desembre de 1998 va passar a prop de la Terra (tanmateix, més enllà de l’òrbita de la Lluna). Visible amb binoculars, mesurava 1 km aproximadament
- 80. Una bona peça: l’agost del 1999 l’asteroide 1999 JM8, de 4 km de llarg i completament desconegut anteriorment, va passar a 8’5 milions de km de la Terra.
- 81. Dimensions de NEOs: 1036 Ganymede : 32 km. 433 Eros : 33x13x13 km. Mínim catalogat: 7 m. NEOs “famosos”: 4179 Toutatis : 2 cossos en contacte. 4660 Nereus : la sonda Muses-C en portarà una mostra. 4769 Castalia : el “cacauet”. 9969 Braille : visitat per la Deep Space1. 2000 SG344 : resulta ser la deixalla d’un coet Apollo...
- 86. 11. Aprofitament econòmic dels asteroides...
- 92. Els bòlids o boles de foc
- 98. 12.3. Classes de meteòrits. Oxygen 49% Silicon 26% Aluminum 7.5% Iron 4.7% Calcium 3.4% Sodium 2.6% Potassium 2.4% Magnesium 1.9% Oxygen 36% Iron 26% Silicon 18% Magnesium 14% Aluminum 1.5% Nickel 1.4% Calcium 1.3% Iron 91% Nickel 8.5% Cobalt 0.6% Earth's crust Stony meteorite Iron meteorite
- 102. La Terra primitiva: bombardeig constant de grans meteòrits.
- 103. Canvis climàtics induïts per impactes d’asteroides o cometes.
- 104. La mare de tots els impactes: formació de la Lluna.
- 111. Tunguska 1908 1998
- 121. Fi.
Editor's Notes
- Sol: 99’8 %. Júpiter: 0’14 (71% de tots els planetes). Saturn: 0’04 (21% de tots els planetes).
- Hipòtesi nebular (Kant i Laplace). Núvol interstel·lar. Col·lapse vers el centre -- Protoestel --Disc d’acreció. Agrumollament gravitatori -- Planetesimals, mini-asteroides, pols.... Frontera del glaç: planetes terrestres / planetes gasosos. 1 M.a.: Vent solar agrana el gas als planetes petits.
- Proliferació de sistemes planetaris extrasolars: diversitat més elevada del que hom preveia.
- Asteroid belt estimated to contain over 1 million asteroids with diameter exceeding one kilometer. Credit: NASA
- ESCENIFICACIÓ DELS CIGRONS Apod 98-03-13 APOD: March 13, 1998 - Asteroids Explanation: No asteroid or comet is known to be on a collision course with Earth. The asteroid designated 1997 XF11 had been predicted to come uncomfortably close, but new estimates place its passing beyond the orbit of the Moon. This earth-approaching asteroid was discovered by SpaceWatch astronomer Jim Scotti in December of last year. Orbital computations using new observations suggested that it would pass within 30,000 miles of the Earth's center on October 26, 2028 - a very near miss considering that the radius of the Earth itself is about 4,000 miles. However, more recent and further refined calculations based on both new and archival data indicate that the closest approach will be 600,000 miles in 2028. Imaged by NASA spacecraft, the three potato-shaped objects above are large main-belt asteroids orbiting between Mars and Jupiter. Shown to the same scale from left to right are Mathilde , Gaspra , and Ida . Mathilde has dimensions of about 37 by 29 miles. The asteroid 1997 XF11 is much smaller, probably a mile wide, yet the impact of an asteroid of this size could have catastrophic effects . Over the last two decades, teams of astronomers have just begun to catalog and track near-earth objects .
- Sistema planetari en formació. Els planetes obren un solc en el núvol de material encara no acretat. Observat realment a Fomalhaut. Space.com Some astronomers study relatively young stars, and the dust that encircles them, looking for clues to planet formation. Last year, researchers found evidence for this scene around a star called Fomalhaut, A newborn Saturn-like planet is thought to create a wake that was observed in the cold dust, leftovers of star formation. Inner planets are shown clearing a hole in the center of the dust disk, but these were inserted by David Hardy with artistic license, not because of solid data. The image also includes asteroids, the theoretical building blocks of some planets. [ Story ]
- The moons of the outer planets show the scars of eons of bombardment, some large enough to have shattered the satellite.
- A view of the debris that might harbor asteroids around zeta Leporis. The debris ring occupies a region of space similar in distance from the host star as compared to our asteroid belt.
- Apod 02-06-23 APOD: 2002 June 23 - Asteroids in the Distance Explanation: Rocks from space hit Earth every day. The larger the rock, though, the less often Earth is struck. Many kilograms of space dust pitter to Earth daily. Larger bits appear initially as a bright meteor . Baseball-sized rocks and ice-balls streak through our atmosphere daily, most evaporating quickly to nothing. Significant threats do exist for rocks near 100 meters in diameter, which strike the Earth roughly every 1000 years. An object this size could cause significant tidal waves were it to strike an ocean, potentially devastating even distant shores. A collision with a massive asteroid , over 1 km across, is more rare , occurring typically millions of years apart, but could have truly global consequences . Many asteroids remain undiscovered . In fact, one was discovered in 1998 as the long blue streak in the above archival image taken by the Hubble Space Telescope. Last week , the small 100-meter asteroid 2002 MN was discovered only after it whizzed by the Earth, passing well within the orbit of the Moon. 2002 MN passed closer than any asteroid since 1994 XM1 . A collision with a large asteroid would not affect Earth's orbit so much as raise dust that would affect Earth's climate . One likely result is a global extinction of many species of life, possibly dwarfing the ongoing extinction occurring now . APOD: March 16, 1998 - Asteroids in the Distance Explanation: Rocks from space hit Earth every day. The larger the rock, though, the less often Earth is struck. Many kilograms of space dust pitter to Earth daily. Larger bits appear initially as a bright meteor . Baseball-sized rocks and ice-balls streak through our atmosphere daily, most evaporating quickly to nothing. Significant threats do exist for rocks near 100 meters in diameter, which strike Earth roughly every 1000 years. An object this size could cause significant tidal waves were it to strike an ocean, potentially devastating even distant shores. A collision with a massive asteroid , over 1 km across, is more rare , occurring typically millions of years apart, but could have truly global consequences . Many asteroids remain undiscovered. In fact, the discovery of several was announced last week; one is shown as the long blue streak in the above photograph . Such an interplanetary collision would not affect Earth's orbit so much as raise dust that would affect Earth's climate . One likely result is a global extinction of many species of life, possibly dwarfing the ongoing extinction occurring now .
- Asteroides primitius: - Interior metàl·lic. - Escorça rocosa. - Part intermèdia barrejada. Col·lisions provoquen diversitat de composicions dels fragments. Proporció de cada tipus depén de la distància al Sol. Classes d’asteroides segons llur espectre de reflexió: Tipus C ( = carbonacis): Molt foscos. Composició complexa (carboni 3%, materials hidratats...); com la de la nebulosa protosolar però sense H ni He. Són més del 75% de tots els asteroides. Exemples: Hygiea , Davida . Tipus S ( = silícics). Lluents (albedo 10-20%). Fe i Ni barrejats amb silicats de Fe. Són el 17% dels coneguts. Predominen a la part interna del Cinyell Principal. Exemples: 15 Eunomia . Tipus M ( = metàl·lics). Lluents (albedo 10-18%). Fe i Ni purs. Abunden al centre del Cinyell Principal. Tipus rars: P (vermellosos), D (molt foscos),...
- Llei de Titius-Bode: seqüència: 0 3 6 12 24 48 96 192 +4: 4 7 10 16 28 52 100 196 dist.real: 3’9 7’2 10 15’2 --- 52 95 192 planeta: Mer Ven Ter Mar --- Jup Sat Urà
- APOD: 2002 July 24 - Our Busy Solar System Explanation: Our Solar System is a busy place. Although the major planets get the most press, a swarm of rocks, comets, and asteroids also exist. The above plot shows the placement of known inner Solar System objects on 2002 July 20. The light blue lines indicate the orbits of planets . The green dots indicate asteroids , officially known as minor planets . The red dots indicate asteroids that come within 1.3 Earth-Sun distances ( AU ) of the Sun and so pose an increased (although small) collision risk with the Earth . Comets appear as dark blue squares, while dark blue points are Jupiter Trojans , asteroids that orbit just ahead of, or just behind Jupiter. Note that most asteroids of the inner Solar System orbit between Mars and Jupiter in the main asteroid belt . Every day this plot shifts with objects nearer the Sun typically shifting the most. The current locations of these objects can be found here .
- A l’entorn dels punts de Lagrange L4 i L5. L4, L5: a 60º. Oscil·lacions cap avant i cap arrere. Achilles (1906). N’hi ha més de 200. Des de la formació del Sistema Solar. Troià de Mart: 5261 Eureka (a L5 de Mart).
- APOD: September 8, 1997 - A Map of Asteroid Vesta Explanation: Vesta is a huge rock 500 kilometers across that orbits out past Mars . Last week, the above map of Vesta created using the Hubble Space Telescope was released showing a rugged surface highlighted by a single crater spanning nearly the entire length of the asteroid . The large crater dominates the lower part of the false-color conglomerate image: blue indicates low terrain, while red indicates raised terrain. Evidence indicates that Vesta underwent a tremendous splintering collision about a billion years ago. In October 1960, a small chunk of this rock believed to have originated on Vesta fell to Earth and was recovered in Australia . A 180 milions de km de la Terra. Depressió en blau (impacte): Diàmetre 460 km. Fondària 12 km. Pic central.
- APOD: 2002 September 19 - Asteroid 1998 KY26 Explanation: A day is just under 11 minutes long on 1998 KY26 , a 30 meter wide, fast-spinning, water-rich asteroid. This computer simulated view of its lumpy surface has a resolution of about 3 meters and is based on radar and optical observations (click on the image for a series of surface views). The observations were made shortly after the discovery of the diminutive world which passed within about 800,000 kilometers of Earth, or about 2 times the Earth-Moon distance, in June of 1998. Around 10 million asteroids of similar size may exist in orbits that also come near Earth's , but little is known about them . However, spinning so fast, tiny 1998 KY26 can not be a loose conglomerate held together by gravity alone. Instead it is likely a monolithic chunk fragmented from a larger asteroid . As the radar and optical data suggest 1998 KY26 has a high water content, this relatively accessible asteroid could be a literal oasis for future space explorers .
- APOD: 2002 August 17 - Asteroid 2002 NY40 Explanation: Asteroid 2002 NY40 will fly by planet Earth early in the morning August 18 Universal Time (late in the evening August 17 Eastern Daylight Time). Approaching to within about 530,000 kilometers or 1.3 times the Earth-Moon distance 2002 NY40 will definitely not be close enough to pose any danger of collision. But it will be close enough and just bright enough for experienced skygazers to see this 800 meter wide space rock in a small telescope or binoculars as it glides quickly through northern skies past the bright star Vega. It will also be close enough to ping with radar , and asteroid hunters using the large Arecibo radio telescope in Puerto Rico expect to determine the three dimensional outline of 2002 NY40. Similar investigations of other near Earth asteroids have revealed some surprising shapes . In this five minute time exposure, recorded at Cerro Tololo Inter-American Observatory on August 14, 2002 NY40 shows
- APOD: 2002 June 30 - Ida and Dactyl : Asteroid and Moon Explanation: This asteroid has a moon ! The robot spacecraft Galileo currently exploring the Jovian system , encountered and photographed two asteroids during its long journey to Jupiter . The second asteroid it photographed, Ida , was discovered to have a moon which appears as a small dot to the right of Ida in this picture . The tiny moon , named Dactyl , is about one mile across, while the potato shaped Ida measures about 36 miles long and 14 miles wide. Dactyl is the first moon of an asteroid ever discovered. The names Ida and Dactyl are based on characters in Greek mythology . Other asteroids are now known to have moons . APOD: August 7, 1999 - Ida and Dactyl : Asteroid and Moon Explanation: This asteroid has a moon ! The robot spacecraft Galileo currently exploring the Jovian system , encountered and photographed two asteroids during its long journey to Jupiter . The second asteroid it photographed, Ida , was discovered to have a moon which appears as a small dot to the right of Ida in this picture . The tiny moon , named Dactyl , is about one mile across, while the potato shaped Ida measures about 36 miles long and 14 miles wide. Dactyl is the first moon of an asteroid ever discovered. The names Ida and Dactyl are based on characters in Greek mythology . Do other asteroids have moons ?
- Asteroid Eugenia is only the second asteroid found with a moon (the other is Ida). Eugenia is made mostly of ice strewn with rocks.
- Apod 00-11-01 APOD: 2000 November 1 - Double Asteroid 90 Antiope Explanation: This eight-frame animation is based on the first ever images of a double asteroid ! Formerly thought to be a single enormous chunk of rock, asteroid 90 Antiope resides in the solar system's main asteroid belt between Mars and Jupiter. Now, these premier images reveal Antiope to actually consist of two 50 mile wide asteroids separated by about 100 miles. Like weights on each end of an elastic string, the pair mutually orbit their center of mass, or balance point in the space between them, once every 16.5 hours. Binary asteroids and asteroids with moons are believed to be rare, but observations of their orbits allow a direct determination of asteroid masses and densities. Surprisingly, Antiope and known asteroid-moon systems are found to have densities closer to ice than rock, despite their relatively dark and unreflective surfaces. These sharp images were made at the Keck Observatory atop the Hawaiian volcano Mauna Kea using newly developed adaptive optics technology to overcome the blurring effect of Earth's atmosphere.
- Apod 00-05-02/2 APOD: 2000 May 10 - Dog-Bone Shaped Asteroid 216 Kleopatra Explanation: An asteroid the size of New Jersey that orbits the Sun between Mars and Jupiter has been discovered to have an unusual dog-bone shape. Asteroid 216 Kleopatra , recently mapped with Earth-based radar , reflects radio waves so well that astronomers speculate it is composed mostly of metals such as nickel and iron . The unusual shape and composition of 216 Kleopatra may derive from the central regions of a tremendous collision between larger asteroids billions of years ago. Kleopatra is not completely solid - its surface is loosely consolidated rubble, although its core may contain large solid-metal lodes. Kleopatra will never strike the Earth , but it may one day serve as a valuable source of raw building materials.
- Apod 00-05-10
- Apod 97-06-30 APOD: June 30, 1997 - NEAR Mathilde Explanation: Hey Earth, look what I found! On the way to visiting the asteroid 433 Eros in February 1999, the Near Earth Asteroid Rendezvous (NEAR) spacecraft flew right by another asteroid: 253 Mathilde last Friday. Shown above is one picture from the encounter. Mathilde is a large chunk of rock roughly 60 kilometers across that orbits the Sun between Mars and Jupiter in the main asteroid belt . Mathilde's surface is very dark and heavily cratered. The NEAR pictures of Mathilde received so far indicate that the asteroid has undergone spectacular collisions, one of which created the huge impact basin in the center, which is estimated to be about 10 kilometers deep. Apod 97/07/01. APOD: July 1, 1997 - Asteroid 253 Mathilde's Large Craters Explanation: You're zipping through the Solar System when you pass ... asteroid 253 Mathilde. This actually happened to NASA's NEAR spacecraft just last Friday. The above picture of the previously unresolved asteroid was released just yesterday . Mathilde's large craters and irregular shape indicates that it has undergone huge collisions with other large space rocks in the past. Mathilde has more large craters than asteroids 243 Ida and 951 Gaspra , which were photographed by the Galileo spacecraft now orbiting Jupiter . In the image center is a crater over 20 kilometers across. Asteroids are rare enough so that spacecraft traveling through even the main asteroid belt need not fear colliding with any - let alone one as large as Mathilde .
- Apod 97-07-01
- Apod 01-08-18 APOD: 2001 August 18 - Phobos : Doomed Moon of Mars Explanation: Mars , the red planet named for the Roman god of war, has two tiny moons, Phobos and Deimos , whose names are derived from the Greek for Fear and Panic. These Martian moons may well be captured asteroids originating in the main asteroid belt between Mars and Jupiter or perhaps from even more distant reaches of the Solar System . In this 1978 Viking 1 orbiter image , the largest moon, Phobos , is indeed seen to be a heavily cratered asteroid-like object. About 17 miles across, Phobos really zips through the Martian sky. Actually rising above Mars' western horizon and setting in the east, it completes an orbit in less than 8 hours. But Phobos is doomed. Phobos orbits so close to Mars, (about 3,600 miles above the surface compared to 250,000 miles for our Moon ) that gravitational tidal forces are dragging it down. In 100 million years or so it will likely crash into the surface or be shattered by stress caused by the relentless tidal forces , the debris forming a ring around Mars. APOD: May 31, 1998 - Phobos : Doomed Moon of Mars Explanation: Phobos is doomed. Mars , the red planet named for the Roman god of war, has two tiny moons, Phobos and Deimos , whose names are derived from the Greek for Fear and Panic. These Martian moons may well be captured asteroids originating in the asteroid belt between Mars and Jupiter or perhaps from even more distant reaches of the Solar System . In this 1977 Viking orbiter image, the largest moon, Phobos , is seen to be a heavily cratered asteroid-like object. It is about 17 miles across and zips through the Martian sky completing an orbit in less than 8 hours. Phobos orbits so close to Mars, (about 3,600 miles above the surface compared to 250,000 miles for our Moon ) that gravitational tidal forces are dragging it down. In 100 million years or so it should crash into the surface or be shattered by stress caused by the relentless tidal forces, the debris forming a ring around Mars.
- Between the orbits of Saturn and Uranus wanders a dark object known as Chiron. It is thought to be an unusually large comet from the outer solar system which wandered too close to a major planet (perhaps Saturn, as seen here), and become trapped in its present orbit.
- Prèviament: telescopi, espectres, meteòrits. Galileo (de camí vers Júpiter). 1991 oct.: 951 Gaspra (del Cinyell Principal), sobrevol. 1993 ago.: 243 Ida (id.): sobrevol. NEAR. 1997 juny: 253 Mathilda (Cinyell Principal), sobrevol. 1998 des.: 433 Eros, falla posar-se en òrbita d’Eros. 2000 feb.: 433 Eros, en òrbita d’Eros; 14 feb.: hi aterra. Deep Space (propulsió iònica). 1999 jul.: 9969 Braille, sobrevol. Cassini (de camí vers Saturn). 2000 gen,: 2685 Masursky, sobrevol.
- APOD: 2002 October 27 - Asteroid Gaspra s Best Face Explanation: Asteroid 951 Gaspra is a huge rock tumbling in space. Gaspra became one of the best-studied asteroids in 1991 when the spacecraft Galileo flew by. In the above photograph , subtle color variations have been exaggerated to highlight changes in reflectivity, surface structure and composition. Gaspra is about 20 kilometers long and orbits the Sun in the main asteroid belt between Mars and Jupiter . APOD: July 12, 1998 - Asteroid Gaspra's Best Face Explanation: Asteroid 951 Gaspra is a huge rock tumbling in space. Gaspra became one of the best-studied asteroids in 1991 when the spacecraft Galileo flew by. In the above photograph , subtle color variations have been exaggerated to highlight changes in reflectivity, surface structure and composition. Gaspra is about 20 kilometers long and orbits the Sun in the main asteroid belt between Mars and Jupiter .
- Futures missions: Muses-C (japonesa). Portarà una mostra de 4660 Nereus el 2007. Rosetta (europea). Vers el cometa Wirtanen (l’assolirà el 2008). Farà flyby de 140 Siwa i de 4979 Otawara (el 2006). Dawk (USA). Òrbita a l’entorn de 4 Vesta (aprox. 2010) i 1 Ceres (aprox. 2014). … i la psicosi de l’impacte: Don Quijote, Earthguard 1,…
- Apod 98-12-28 APOD: December 28, 1998 - NEAR to Asteroid Eros Explanation: On December 23, the NEAR spacecraft flew by asteroid 433 Eros . NEAR was originally scheduled to brake and orbit Eros, but an unexpected shutdown of its main engine caused this plan to be aborted. NEAR will now be reset and attempt to return to orbit Eros in early 2000. The above image sequence was taken as NEAR approached Eros. The rotation of the asteroid is visible in the successive frames. When NEAR is fully operational, it will likely provoke the world's largest telescopes to point not toward asteroid Eros but to positions indicated by another of NEAR's instruments: its gamma-ray burst (GRB) detector . NEAR's distant GRB detector happens now to be in a unique position to contribute information crucial to the rapid acquisition of accurate GRB positions . També apod 00-02-05 APOD: 2000 February 5 - NEAR to Asteroid Eros Explanation: On December 23, 1998 the Near Earth Asteroid Rendezvous (NEAR) spacecraft flew by asteroid 433 Eros . The robotic spacecraft was intended to brake and orbit Eros, but an unexpected shutdown of its main engine caused this plan to be aborted. Now closing with the asteroid again, NEAR will make another attempt to enter Eros ' orbit on February 14th ... Valentine's Day, of course! A successful encounter would make NEAR the first spacecraft ever to orbit an asteroid . This image sequence was taken as NEAR approached Eros in 1998. The rotation of the asteroid is visible in the successive frames. While cruising through the solar system, NEAR has also been hunting for gamma-ray bursts as part of the operational Interplanetary Network .
- Apod 00-02-10 APOD: 2000 February 10 - Eros Encounter Nears Explanation: After an unanticipated extra trip around the Sun, the NEAR spacecraft is now politely approaching asteroid 433 , Eros , at a respectful relative speed of about 20 miles per hour. Still nearly 2,000 miles distant, NEAR will close to within approximately 200 miles by February 14th - Valentine's Day. If all goes well, the spacecraft will then be captured by the gentle attraction of Eros ' gravity, becoming the first artificial moon of an asteroid . While Eros is not round it is certainly not heart-shaped either as seen in this series of frames showing the roughly 20 x 8 x 8 mile asteroid during its 5.27 hour rotation period. Different perspectives clearly show a gouge or saddle and a large impact crater with a raised rim near the asteroid's narrow waist. The frames were recorded by the NEAR spacecraft's multi-spectral imager on February 4th from a range of 4,600 miles.
- Apod 00-03-16 i 01-02-11 APOD: 2000 March 16 - NEAR Shoemaker Views Eros Explanation: Orbiting asteroid 433 Eros, 145 million miles from Earth, NASA's NEAR spacecraft has been returning stunning views as its year long mission of exploration gets underway . A mosaic of recent NEAR images recorded at a range of about 127 miles, this picture illustrates some of the amazing contrasts which apparently exist within the domain of this diminutive world. Features as small as 65 feet are visible here, while long shadows emphasize the differences in the cratered regions at the left and smooth groved terrain at right. Up close , the undulating surface seems flecked with bright deposits and peppered with enormous boulders . As NEAR is poised to investigate mysteries of the formation of asteroids and the origins of the solar system from this unprecedented vantage point , NASA has renamed the spacecraft NEAR Shoemaker in honor of the late Dr. Eugene M. Shoemaker , legendary geologist, comet hunter , and inspirational pioneer in the field of interplanetary science. APOD: 2001 February 11 - NEAR Shoemaker Views Eros Explanation: Orbiting asteroid 433 Eros, 145 million miles from Earth, NASA's NEAR spacecraft has been returning stunning views as its year long mission of exploration nears completion . A mosaic of NEAR images recorded at a range of about 127 miles, this picture illustrates some of the amazing contrasts which apparently exist within the domain of this diminutive world. Features as small as 65 feet are visible here, while long shadows emphasize the differences in the cratered regions at the left and smooth grooved terrain at right. Up close , the undulating surface seems flecked with bright deposits and peppered with enormous boulders . Last year, NASA changed the spacecraft name from NEAR to NEAR-Shoemaker in honor of the late Dr. Eugene M. Shoemaker , legendary geologist, comet hunter , and inspirational pioneer in the field of interplanetary science. Tomorrow , NEAR-Shoemaker will complete its scheduled mission as it will be commanded to descend to the surface of the ancient asteroid .
- APOD: 2001 June 5 - Asteroid Eros Reconstructed Explanation: Orbiting the Sun between Mars and Earth , asteroid 433 Eros was visited by the robot spacecraft NEAR-Shoemaker in 2000 February. High-resolution surface measurements made by NEAR 's Laser Rangefinder ( NLR ) have been combined into the above visualization based on the derived 3D model of the tumbling space rock . NEAR allowed scientists to discover that Eros is a single solid body, that its composition is nearly uniform, and that it formed during the early years of our Solar System . Mysteries remain, however, including why some rocks on the surface have disintegrated. On 2001 February 12, the NEAR mission drew to a dramatic close as it was crash landed onto the asteroid's surface , surviving well enough to return an analysis of the composition of the surface regolith . Unless re-awakened by NASA , NEAR will likely remain on the asteroid for billions of years as a monument to human ingenuity at the turn of the third millennium .
- Apod 00-03-08 APOD: 2000 March 8 - Nearer To Asteroid Eros Explanation: As the robot spacecraft NEAR lowers itself toward asteroid 433 Eros , more surface details are becoming visible. Last week's maneuvers brought NEAR to within 204 kilometers of the floating mountain's surface . With increased resolution, NEAR's camera then documented Eros ' unusual shape , craters large and small, boulders , and mysterious grooves similar to asteroid Gaspra and Martian moon Phobos . If you could stand on Eros , you would still be too small to be visible on this recent image , which shows features as small as 20 meters across. However, you would feel gravity only 1/1000 that on Earth , so that you could easily jump over even this large 5 kilometer wide crater. També, apod 00-02-16 Sonda NEAR a 204 km de distància. Els menors detalls: 20 m. Cràter: 5 km d’ample. Gravetat: 1/1000 de la de la Terra (el cràter és saltable). APOD: 2000 February 21 - A Giant Gouge on Asteroid Eros Explanation: Asteroid 433 Eros is posing several riddles. NASA's robot spacecraft NEAR began orbiting the 30-kilometer space rock last week, and new pictures are now being beamed back to Earth regularly. As usual in science , when you arrive at a place you've never been before , you see things you don't immediately understand . Scientists are contemplating , for example, the cause of the above-pictured giant gouge in the middle of Eros. Intriguing internal features include groves oriented parallel to the asteroid 's length and the relative paucity of craters. These indicate that the gouge formed well after the asteroid itself. One question answered by the shape and density is that, unlike asteroid 253 Mathilde , Eros is not a pile of rocks but one big rock . Astronomers are hopeful that data taken over the coming year might indicate the nature and origin of the baffling bright patches. APOD: 2000 February 16 - Eros From Orbit Explanation: On February 14th, the NEAR spacecraft became the first artificial moon of an asteroid . Captured by the gentle gravity of a 20 mile long slipper-shaped mountain of rock, NEAR recorded this premier image while orbiting asteroid 433 Eros at a distance of about 200 miles. The image shows features as small as 100 feet across in a view dominated by a 3 mile wide crater near Eros' narrow waist. Enticing layers and grooves are visible within the crater rim along with an enormous 170 foot boulder lying on the crater floor (near picture center). Although Eros is a large S-type near-earth asteroid , it is still not massive enough for its own gravity to have shaped it into a planet-like spherical form. By comparison , Eros has less than a thousandth Earth's gravity, so a 100 pound object on Earth would weigh about 1 ounce on Eros. A baseball thrown at 22 miles per hour would completely escape into space. The weak gravity and irregular shape make orbiting Eros a delicate challenge for NEAR's controllers who plan a year long exploration program with possible close approaches to the asteroid's surface .
- Apod 00-08-24 APOD: 2000 August 24 - Eros At Sunset Explanation: Gleaming in the rays of the setting sun, boulders litter the rugged surface of asteroid 433 Eros . The brightest boulder, at the edge of the large, shadowy crater near this picture's bottom center, is about 30 meters (100 feet) across. In orbit around Eros since February 2000, the NEAR Shoemaker spacecraft's camera recorded the dramatic view earlier this month from an altitude of about 50 kilometers. Eros itself orbits the Sun with a perihelion of 1.13 Astronomical Units (AU) and aphelion of 1.78 AU. Part of a class of near-Earth asteroids , it spends much of its time between the orbits of Mars (at 1.5 AU) and Earth (at 1 AU) ... but it wasn't always that way. Eros and other near-Earth asteroids originally orbited in the main asteroid belt , between Jupiter and Mars . Over time, the gravitational influence of Jupiter and other planets perturbed their orbits sending them on trajectories closer to Earth.
- Apod 00-05-25 APOD: 2000 May 25 - Eros Horizon View Explanation: Since April 30, the robotic NEAR-Shoemaker spacecraft has been orbiting only 31 miles from asteroid Eros . Cruising over the asteroid's north and south poles at a leisurely 7 miles per hour, the spacecraft completes an orbit once every 1.2 earth days. This dramatic horizon view recorded by the spacecraft's camera on May 18 spans about 0.8 miles and reveals features as small as 13 feet across. Emphasized by long, harsh shadows produced by the low sun angle, the rolling surface of Eros is seen to be strewn with boulders and craters with a range of sizes. The jagged-looking boulder near the picture center is over 190 feet tall. While gathering sharp pictures of Eros' surface, experimenters will also take advantage of the close orbit to explore the asteroid's surface composition and internal structure, and search for a magnetic field.
- APOD: 2000 July 21 - Eros Craters And Boulders Explanation: From a delicate orbit around asteroid 433 Eros, the NEAR Shoemaker spacecraft's camera has now imaged the entire surface of the small oddly-shaped world at least once. Recorded on July 7th from a distance of 50 kilometers, this dramatic view is about 1.8 kilometers across. It shows the walls and rims of two large overlapping impact craters on the horizon. Massive boulders which may be debris from the impacts are perched along the crater edges. The prominent boulder on the horizon near picture center is about 40 meters long. In fact, the NEAR mission to Eros has shown that along with craters and boulders, grooves and ridges are also common on the asteroid's surface. While the craters are clearly of impact origin, puzzles about the other surface features still remain. On July 13, controllers fired the spacecraft thrusters and moved NEAR Shoemaker to an even closer 35 kilometer orbit to enable higher resolution surface studies.
- Apod 00-08-03 i 00-08-24 APOD: 2000 August 03 - 22 Miles From Eros Explanation: Last month the NEAR Shoemaker spacecraft swooped closer to Eros, orbiting only 22 miles (36 kilometers) from the center of the asteroid. These two images taken on July 19 ( left ) and July 24 ( right ) reveal the diminutive world's pocked and mottled surface in amazing detail, showing features as small as 19 feet (6 meters) across. Eros is thought to be a primordial , undifferentiated asteroid based on X-ray and gamma-ray studies of its surface composition. In the left picture, its surface layer or regolith is seen to be laced with bright and dark regions while in the right hand image dark regolith appears to have filled in some crater floors. The left and right images span an area about 2,600 feet (800 meters) and 3,000 ft (900 meters) wide respectively. On July 31, NEAR Shoemaker returned to its familiar 31 mile (50 kilometer) orbit , circling Eros serenely at about 6 miles per hour.
- Apod 02-03-03 APOD: 2002 March 3 - The Regolith of Asteroid Eros Explanation: From fifty kilometers above asteroid Eros, the surface inside one of its largest craters appears covered with an unusual substance: regolith . The thickness and composition of the surface dust that is regolith remains a topic of much research. Much of the regolith on 433 Eros was probably created by numerous small impacts during its long history. In this representative-color view taken by the robot spacecraft NEAR-SHOEMAKER that orbited Eros in 2000 and 2001, brown areas indicate regolith that has been chemically altered by exposure to the solar wind during micrometeorite impacts. White areas are thought to have undergone relatively less exposure. The boulders visible inside the crater appear brown, indicating either that they are old enough to have a surface itself tanned by the solar wind , or that they have somehow become covered with some dark surface regolith .
- Apod 00-10-27 APOD: 2000 October 27 - Close To Eros Explanation: Scroll right and fly close over asteroid Eros! This long mosaic was constructed of images returned yesterday by the NEAR Shoemaker spacecraft as it orbited to within 6.4 kilometers of a spot in the southern hemisphere of the rotating asteroid's surface. That distance (about 21,000 feet) is less than the cruising altitude of most commercial airline flights. The digital images show that while many regions appear smooth with craters filled in by an accumulation of loose regolith , much of Eros' surface is littered with rocks and boulders. The large boulder glinting in the sunlight at the far left, just above the center of the mosaic, spans approximately 25 meters. In the high-resolution view, the smallest rocks visible are roughly human-sized at about 1.4 meters (5 feet) across. The car-sized Near Shoemaker spacecraft is now on its way to a higher, more stable orbit about 200 kilometers above asteroid Eros .
- Apod 01-01-22 APOD: 2001 January 22 - A Two Toned Crater on Asteroid Eros Explanation: What lies beneath the surface of asteroid Eros? This image taken two weeks ago by the robot NEAR spacecraft orbiting the dark asteroid shows a kilometer-wide crater where some type of light material lies beneath some of the darker surface regolith . This light substance, seen on other photographs , may be relatively fresh material not yet well exposed to a darkening solar wind and micro meteorite impacts. As fuel wanes, NASA plans to end the NEAR spacecraft mission on February 12 with a spectacular controlled descent to the asteroid's surface . Although not designed to survive a landing, it is hoped that NEAR will be able to record and relay high-resolution pictures on its way down.
- Apod 00-10-26 APOD: 2000 October 26 - The Map Of Eros Explanation: This map of Eros was constructed from a mosaic of images recorded by the NEAR Shoemaker spacecraft, currently orbiting the 40 x 14 x 14 kilometer asteroid. A simple cylindrical projection of an irregularly shaped world , the map's individual images don't always match up at the edges. Shown here, place names have been proposed to describe the geography of Eros with a fitting theme, though. They are based on romantic figures in the history and literature of the cultures of planet Earth. The largest feature, Himeros , is a depression about 10 kilometers wide. In Greek mythology , Himeros was an attendant of Eros and the personification of the longing of love. Today, after safely surveying Eros for the past eight months, NEAR Shoemaker is scheduled to make a daring close approach to the asteroid, briefly flying to within about 6 kilometers of its surface. Images returned from that distance are expected to show features less than 1 meter across.
- Apod 01-02-12 APOD: 2001 February 12 - Approaching Asteroid Eros Explanation: Today, at about 3 pm EST, the first human-made spacecraft is scheduled to touchdown on an asteroid . At an impact speed of 8 kilometers per hour, it is most probable that the robot spacecraft NEAR-Shoemaker will not survive its planned collision with 433 Eros . A primary reason for the descent, diagrammed above , will be to take images during the four hours on the way down. If all goes well, some of those pictures will show surface features as small as 10 centimeters across. Scientists hope to learn more about this unusual Manhattan -sized rock that is, quite possibly, older than the Earth .
- Apod 01-02-06 APOD: 2001 February 6 - Touchdown Site on Asteroid Eros Explanation: The first controlled descent of a spacecraft onto an asteroid is scheduled to occur next week. The robot spacecraft NEAR-Shoemaker has been orbiting asteroid Eros for nearly one year On February 12, before maneuvering fuel wanes, NASA will command the craft to descend right down onto the surface . Although the spacecraft is not expected to survive the impact, it is hoped that it can transmit photographs showing surface details as small as 10 centimeters during the descent. The touchdown site, shown above by the yellow circle, is on the edge of the large saddle shaped feature known as Himeros , and near the boundary between two distinct types of surface terrain.
- APOD: 2001 August 24 - NEAR at Eros : Before Touchdown Explanation: On 12 February, 2001, the NEAR-Shoemaker spacecraft gently touched-down on the the surface of Eros -- the first ever landing on an asteroid . During the descent, the spacecraft's camera recorded successive images of the diminutive world's surface , revealing fractured boulders, dust filled craters, and a mysterious collapsed channel. The last frame , seen in the above montage at the far left, was taken at a range of 128 meters. Expanded in the inset, it shows surface features a few centimeters across. Stereo experimenter Patrick Vantuyne, constructed this montage from the final images in the landing sequence, carefully identifying the overlapping areas in successive frames. Frames which overlap were taken by the spacecraft from slightly different viewpoints , allowing Vantuyne to construct close-up stereo images of the surface of asteroid 433 Eros.
- Apod 01-02-13 APOD: 2001 February 13 - NEAR Spacecraft Survives Landing on Asteroid Eros Explanation: Yesterday NEAR-Shoemaker became the first spacecraft to land on an asteroid and send signals back from its surface. Since the robot spacecraft was not designed for such a contingency , the success of the landing on asteroid 433 Eros was not assured. Shown above is the last picture taken by NEAR-Shoemaker before its touchdown. The streaking on the lower part of the image was caused by the loss of telemetry as the satellite impacted the surface . The image was taken 130 meters above the surface and spans 6 meters across. Rocks as small as a human hand are visible. As engineers continue to try to communicate with the beached car-sized spacecraft, scientists will work to understand features visible in the highest resolution photographs ever taken of an asteroid.
- Apod 01-03-05 APOD: 2001 March 5 - Survivor : NEAR Shoemaker On Asteroid Eros Explanation: Not part of a television game series, the NEAR Shoemaker spacecraft survived its unprecedented landing on an asteroid last month. As suggested in the illustration inset above , the car-sized probe likely rests gently on the tips of its solar panels having touched down under the influence of asteroid Eros' feeble gravity. Fortunately, the spacecraft's solar panels were bathed in sunlight and able to power NEAR's gamma-ray spectrometer . Perched on the asteroid, this instrument can determine the composition of Eros to a depth of about 10 centimeters with unanticipated accuracy by measuring the gamma-ray signatures of the atomic nuclei present. The data returned from the surface of Eros are plotted above and show clearly features corresponding to Iron, Oxygen, Silicon, and Potassium in the asteroid's regolith . Also briefly operating on Eros, NEAR's magnetometer has indicated that no surface magnetic field is discernible. Now turned off , NEAR Shoemaker could remain preserved in its present location, the vicinity of the huge, saddle-shaped feature dubbed Himeros , for billions of years. But, as the asteroid orbits , the spacecraft's solar panels will be repeatedly turned toward the Sun ... offering the possibility of reawakening this survivor .
- Apod 00-03-27 APOD: 2000 March 27 - Flying Over Asteroid Eros Explanation: What would it look like to fly over an asteroid? Spacecraft NEAR Shoemaker in orbit around asteroid 433 Eros found out earlier this month when it recorded its first fly-over sequence. The saddle region of the Sun-orbiting space-mountain appears to zip past the camera in this condensed hour-long time-lapse sequence . The spacecraft was orbiting about 200 kilometers above the asteroid . Movies such as this are scientifically useful for discerning between regions that are naturally dark and regions that have their brightness dominated by shadows. The week before, a bright X-ray burst from the Sun allowed NEAR's X-ray spectrometer to detect the presence of several elements on Eros' surface by their X-ray fluorescent signatures.
- Apod 00-04-17 APOD: 2000 April 17 - Flying Over Asteroid Eros West End Explanation: The robot spacecraft NEAR Shoemaker continues to orbit asteroid Eros. This condensed 40-minute long time-lapse sequence taken last month shows what it looks like to pass within 200 kilometers of Eros ' west end. The north pole of the rotating mountain is toward the bottom of the picture. This month NEAR-Shoemaker closes to within 100 kilometers, and by the end of this month will orbit only 50 kilometers from the center of this 33-kilometer long asteroid . One reason for moving in so close is to determine if 433 Eros has a magnetic field . NEAR Shoemaker, launched in 1996, is run by a computer similar to a PC released 15 years ago (12 MHz, 256K).
- Apod 00-02-21 La sonda NEAR hi va orbitar el febrer del 2000. Misteriosa zona enclotada: És recent (no hi ha gaires cràters). Què són els sécs longitudinals? La sonda NEAR hi va orbitar el febrer del 2000. Misteriosa zona enclotada: És recent (no hi ha gaires cràters). Què són els sécs longitudinals? APOD: 2000 February 21 - A Giant Gouge on Asteroid Eros Explanation: Asteroid 433 Eros is posing several riddles. NASA's robot spacecraft NEAR began orbiting the 30-kilometer space rock last week, and new pictures are now being beamed back to Earth regularly. As usual in science , when you arrive at a place you've never been before , you see things you don't immediately understand . Scientists are contemplating , for example, the cause of the above-pictured giant gouge in the middle of Eros. Intriguing internal features include groves oriented parallel to the asteroid 's length and the relative paucity of craters. These indicate that the gouge formed well after the asteroid itself. One question answered by the shape and density is that, unlike asteroid 253 Mathilde , Eros is not a pile of rocks but one big rock . Astronomers are hopeful that data taken over the coming year might indicate the nature and origin of the baffling bright patches.
- Apod 01-10-09 APOD: 2001 October 9 - The Past of Asteroid Eros Explanation: How did large rocks come to be scattered on the surface of asteroid Eros? Eros stands out not only because of its proximity to Earth but also because it was visited recently by NASA 's NEAR-Shoemaker spacecraft . After arriving at Eros in 2000 February, the robot probe was maneuvered to a controlled landing earlier this year. Although NEAR-Shoemaker is no longer active, scientists are still poring over the images and data, finding new mysteries, and drawing new hypotheses about the ancient tumbling space mountain. For example, analyzing the locations of rocks has led to the hypothesis that many of them originated in a single large collision that occurred possibly about a billion years ago. Still unknown, however, includes why Eros has unusual ponds of blue dust.
- Apod 00-02-14 APOD: 2000 February 14 - An Unexpected Asteroid Valentine Explanation: Maybe the Moon owns our hearts , but this won't stop the occasional asteroid from sending us a valentine . Friday, to the surprise of many, the NEAR mission on approach to asteroid 433 EROS photographed what appears to be a heart-shaped depression . After NEAR reaches the asteroid today, NASA plans a series of maneuvers to make the robot spacecraft the first ever to orbit an asteroid. More detailed pictures will soon be taken of the 33 kilometer long asteroid EROS and this 5 kilometer long depression. Most likely, fortuitous lighting and viewing angles accentuate the apparent heart shape -- but don't tell the Moon .
- Apod 97-01-20 APOD: January 20, 1997 - Earth Nears Asteroid Toutatis Explanation : On November 29, 1996 the Earth came within 3.3 million miles of the asteroid Toutatis. Above is a computer simulated picture of this spectacle from the surface of Toutatis (a 2.5 degree field of view looking toward Earth). In Earth's sky , Toutatis appeared only as a faint object moving against a background of stars. Also known as Earth-crossing asteroid 4179 , Toutatis is in an eccentric 4 year orbit which moves it from the asteroid belt between Mars and Jupiter to just inside Earth's orbit. When the Earth passed near it in 1992 Toutatis was imaged by radar and seen to be two irregularly shaped lumps, perhaps joined by a narrow neck. This bizarre object is up to 1.5 miles wide, 2.9 miles long, and is tumbling through space . In the year 2004, on September 29, the Earth will pass very near Toutatis , closing to within a million miles (4 times the Earth-Moon distance) - the closest approach predicted for any asteroid or comet between now and 2060. Studies of Toutatis and other Earth-crossing asteroids help reveal connections between the Solar System's meteorites , main-belt asteroids and comets . These wayward asteroids also offer tantalizing targets for robotic exploration and, over time, represent potential collision hazards for planet Earth !
- APOD: 2001 December 24 - Asteroid 1998 WT24 Passes Near Earth Explanation: Last week, an asteroid approached unusually close to the Earth. Passing well outside the orbit of our Moon, Asteroid 1998 WT24 posed no danger, but became bright enough to see with binoculars and to track with radar . Pictured above , the kilometer-sized asteroid was imaged crossing the sky on December 14, two days before closest approach . Every few years, an asteroid will actually pass inside the orbit of the Moon. Large impact features on the Earth are testaments to asteroids or comets that actually impacted the Earth in the distant past. Astronomers continue to discover, track, and study potentially hazardous asteroids with a goal of making planet Earth a safer place .
- Apod 99-09-01 APOD: September 1, 1999 - 1999 JM8: A Rock Too Close Explanation: Nearly four kilometers across, the huge rock known as 1999 JM8 silently passed only 8.5 million kilometers from the Earth in early August. The small asteroid was completely unknown before May. Every few centuries , a rock like this impacts the Earth, with the potential to disrupt modern civilization. Radar from two of the largest radio telescopes , Arecibo and Goldstone , tracked and imaged the Apollo asteroid as it approached to only 22 times the distance to the Moon. Although 1999 JM8 missed the Earth, thousands of similar but unknown asteroids likely exist that cross Earth's orbit. In fact, four asteroids have passed inside the orbit of the Moon within the last decade. Possibly of larger concern to humanity are the more numerous rocks near 100 meters across. Were one of these to strike an ocean, a dangerous tidal wave might occur.
- Apod 97-06-18 APOD: June 18, 1997 - Asteroid 3753: Earth's Curious Companion Explanation: Earth is not alone. It orbits the Sun with a small companion: Asteroid 3753 . First discovered in 1986 and designated 1986 OT, this five kilometer rock was recently found to orbit the Sun while executing a strange dance with the Earth . A portion of the asteroid's complex orbit is shown above. As the Earth orbits once, Asteroid 3753 follows the yellow line - while also orbiting the Sun. Each time around, however, the yellow kidney-bean traced by Asteroid 3753 shifts slightly - eventually going from trailing the Earth to leading the Earth. Every 385 years the cycle repeats. Because the plane of 3753's orbit is tilted when compared to the Earth's orbit, the two will never collide . In autumn 1997, Asteroid 3753 will pass below the Earth's South Pole at about 100 times the distance to the Moon . It will, however, be very faint - about 15th magnitude - 10,000 times fainter than the dimmest star without a telescope. Suggestions are being taken for a good name for this asteroid.
- A recently discovered asteroid is playing a cat-and-mouse game with Earth. The space object, which follows a similar path to our own around the Sun, will cross the Earth's orbit on Wednesday. Astronomers say there is no danger of it hitting the planet because the Earth's gravity keeps it at bay. There's no possibility that this asteroid could hit Earth Don Yeomans, Nasa The asteroid, known as 2002 AA29, will pass within 5.9 million kilometres (3.7 million miles) of the planet. This is the closest it has come for almost a century but is no near miss in astronomical terms. The asteroid was spotted last year by an Air Force telescope used by the US space agency (Nasa) to track near-Earth objects. The rock is about 60 metres (200 feet) across and has a very unusual orbit. Read more about Earth's little brother Sneaking up The asteroid races around the Sun on a similar path to the Earth. Every now and again, the two change places, which is what will happen on Wednesday. This time, the asteroid will close on Earth and gravity will force it into a lower, faster orbit. It will then speed on ahead and should catch us up again in 95 years. "There's no possibility that this asteroid could hit Earth, because Earth's gravity rebuffs its periodic advances and keeps it at bay," said Dr Don Yeomans of Nasa's Jet Propulsion Laboratory. "The asteroid and Earth take turns sneaking up on each other, but they never get too close." The object is too small to be easily seen from Earth. It is of great interest to astronomers, however. They predict that its path will change in about 600 years but it will never become a true satellite like the Moon.
- The first asteroid discovered to orbit the Sun in nearly the same path as Earth will make its closest approach to our planet this month before scurrying away for 95 years. The space rock, measuring about 60 meters (approximately 200 feet) across, is like a mouse teasing a cat. According to an international team of astronomers, including a researcher from NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif., the asteroid approaches the Earth, first on one side and then on the other. The team's report appeared in the October 2002 issue of the journal Meteoritics & Planetary Science. The asteroid, named 2002 AA29, traces an unusual horseshoe pattern relative to Earth. The asteroid alternately leads and follows Earth around the Sun without ever passing it. "In some ways, the Earth and this asteroid are like two racecars on a circular track," said JPL's Dr. Paul Chodas, who discovered the object's unusual motion. "Right now the asteroid is on a slightly slower track just outside Earth's, and our planet is catching up," he said. On Jan. 8, 2003, the tiny body will come within approximately 5.9 million kilometers (3.7 million miles) of Earth, its closest approach for almost a century. "Unlike racecars, the two bodies will not pass when they approach each other," Chodas said. "Instead, the combined gravitational effects of the Earth and Sun will nudge the asteroid onto a slightly faster track just inside Earth's, and it will begin to pull ahead," he said. In 95 years, the asteroid will have advanced all the way around to where it is catching up to the Earth from behind. A similar interaction with gravity from both the Earth and Sun will then push the asteroid back onto a slower outside track, and the pattern will repeat. To an observer moving with the Earth, the asteroid appears to trace out a horseshoe pattern. "There's no possibility that this asteroid could hit Earth, because Earth's gravity rebuffs its periodic advances and keeps it at bay," said Dr. Don Yeomans, JPL manager of NASA's Near Earth Objects Program Office. "The asteroid and Earth take turns sneaking up on each other, but they never get too close," he said. The team's calculations show that in about 600 years, the asteroid may begin looping around Earth like a tiny, distant quasi-moon. "The asteroid will appear to orbit the Earth at that time, but in fact it will be too far away to be considered a true satellite of our planet," Chodas said. "Our calculations indicate the space rock will circle the Earth as a quasi-satellite for about 40 years before resuming its horseshoe orbital pattern."
- Asteroid City by Bryce Jacobs Asteroids could be the perfect “vessels” for interstellar generation ships or deep space habitats.
- Don Dixon Portfolio Images 101-150 (1974-1978)) / 106- Asteroid Mining Asteroid Mining - electromagnetic tracks eject rock to maneuver an asteroid into orbit between Earth and Moon
- Don Dixon Portfolio Images 101-150 (1974-1978)) / 111- Operation Asteroid Operation Asteroid - a mass driver steers an asteroid to lunar orbit, where it will be mined
- While three-quarters of the overall NEO risk is due to large asteroids, the most likely impact to occur in the foreseeable future will be caused by a small asteroid. Image Credit: www.s-d-g.freeserve.co.uk
- Apod 98-12-29 APOD: December 29, 1998 - A Geminid from Gemini Explanation: The Leonid meteor shower was not the only good meteor shower this season. Earlier this month, the annual Geminids meteor shower peaked, featuring as many as 140 meteors per hour from some locations. Geminid meteors can be seen streaking away from the constellation of Gemini , as depicted in the above all-sky photograph. The origin of the Geminid meteors is somewhat uncertain but thought to be small bits broken off the unusual asteroid 3200 Phaetheon . Many observers reported that the 1998 Geminids were typically less bright than the 1998 Leonids , but appeared more bunched, with groups of two or three meteors sometimes appearing simultaneously. Next years' Geminids might be better yet.
- Apod 02-12-26 APOD: 2002 December 26 - Searching for Meteorites in Antarctica Explanation: Where is the best place on Earth to find meteorites ? Although meteors fall all over the world, they usually just sink to the bottom of an ocean , are buried by shifting terrain, or are easily confused with terrestrial rocks . At the bottom of the Earth, however, in East Antarctica , huge sheets of blue ice remain pure and barren. When traversing such a sheet, a dark rock will stick out . These rocks have a high probability of being true meteorites -- likely pieces of another world. An explosion or impact might have catapulted these meteorites from the Moon , Mars , or even an asteroid , yielding valuable information about these distant worlds and our early Solar System . Small teams of snowmobiling explorers so far have found thousands. Pictured above , ice-trekkers search a field 25-kilometers in front of Otway Massif in the Transantarctic Mountain Range during the Antarctic summer of 1995-1996.
- 99.09.01 (?): Salt from the Sky This patch of colored salt crystal was inside a stony meteorite that fell to Earth in Monahans, Texas. Several boys playing basketball found the meteorite. First they lent it to NASA, then they sold it on the internet.
- Don Dixon Portfolio Images 051-100 (1968-1974) / 060- Meteoric Rain Meteoric Rain - during the formation of the earth, millions of tons of dust and rock rain down every day
- Don Dixon Portfolio Images 301-350 (1989-2000) / 346- Fire Over Ice a huge fireball exploding over the Greenland ice cap, cover November, 1998 Scientific American - painting by Don Dixon
- Don Dixon Portfolio Images 101-150 (1974-1978)) / 129- Asteroid Impact Asteroid Impact - devasting impacts on the young earth may have restarted evolution several times
- Apod 96-01-12 APOD: January 12, 1996 - Mare Orientale Explanation: Looking like a target ring bull's-eye, the Mare Orientale is one of the most striking large scale lunar features. Located on the Moon 's extreme western edge, this impact basin is unfortunately difficult to see from an earthbound perspective. It is over 3 billion years old, about 600 miles across and was formed by the impact of an asteroid sized object. The collision caused ripples in the lunar crust resulting in the three concentric circular features visible in this 1967 photograph made by NASA's Lunar Orbiter 4. Molten lava from the Moon's interior flooded the impact site through the fractured crust creating a mare . Dark, smooth regions on the moon are called mare (Latin for sea), because early astronomers thought these areas might be oceans.
- Apod 02-11-23 Explanation: Like a target ring bull's-eye, the Mare Orientale is one of the most striking large scale lunar features. Located on the Moon's extreme western edge, this impact basin is unfortunately difficult to see from an earthbound perspective . It is over 3 billion years old, about 600 miles across and was formed by the impact of an asteroid sized object. The collision caused ripples in the lunar crust resulting in the three concentric circular features visible in this 1967 photograph made by NASA's Lunar Orbiter 4. Molten lava from the Moon's interior flooded the impact site through the fractured crust creating a mare . Dark, smooth regions on the moon are called mare (Latin for sea), because early astronomers thought these areas might be oceans.
- Apod 96-02-03 APOD: February 3, 1996 - A Huge Impact Crater on Mars Explanation: What hit Mars ? The impact crater Schiparelli near the center of the above image was likely caused by a collision with an object the size of an asteroid . Also evident in this full face mosaic of Mars are numerous craters from many other impacts with smaller objects over billions of years. At the lower right, white carbon dioxide frost can be seen in the Hellas basin. The frost forms because temperatures can drop as low as -140 degrees Celsius on Mars . Some Martian regions, however, occasionally reach as high as 20 degrees Celsius - a typical room temperature here on Earth .
- Apod 97-08-15 APOD: August 15, 1997 - Impact on Europa Explanation: This bull's-eye pattern marks the impact of a mountain-sized comet or asteroid on the icy surface of Jupiter's moon Europa . Recorded by the Galileo spacecraft in April of this year, the composite false color image clearly reveals the telltale concentric fractures which cover about 86 miles - roughly equivalent to the Island of Hawaii . The fat reddish and finer blue-green lines overlay the impact fractures and must therefore be younger surface features formed after the impact. The dark red color may be the result of a a relatively dirty water-ice mixture. The possibility of liquid water below the ice has fueled speculation that life may exist on this large and distant moon .
- Giant Crater The largest known impact crater in the solar system is on our moon. More than 1,300 miles (2,100 kilometers) across, the Aitken Basin scars the moon's south pole. Scientists believe it was made by an asteroid crashing into the lunar surface.
- Arizona Crater The Barringer Meteor Crater in Arizona is almost a mile (more than a kilometer) across. It's thought to be the result of a meteor impact 49,000 years ago. More than 100 impact craters have been identified on Earth so far. Credit: D. Roddy (LPI)
- Impact of the Tunguska explosion is visible even after 90 years. Credit: Galena HS
- Apod 00-02-26 APOD: 2000 February 26 - Impact : 65 Million Years Ago Explanation: What killed the dinosaurs ? Their sudden disappearance 65 million years ago, along with about 70 percent of all species then living on Earth, is known as the K-T event (Cretaceous-Tertiary Mass Extinction event). Geologists and paleontologists often entertain the idea that a large asteroid or comet impacting the Earth was the culprit. In such a cosmic catastrophe, the good(!) news would be that the impact would generate firestorms, tidal waves, earthquakes, and hurricane winds. As for the bad news ... debris thrown into the atmosphere would have a serious global environmental consequences, creating extended periods of darkness, low temperatures, and acid rains - resulting in a planet-wide extinction event. In 1990, dramatic support for this theory came from cosmochemist Alan Hildebrand's revelation of a 65 million year old, 112 mile wide ring structure still detectable under layers of sediment in the Yucatan Peninsula region of Mexico. The outlines of the structure, called the Chicxulub crater (named for a local village), are visible in the above representation of gravity and magnetic field data from the region. In addition to having the right age, the crater is consistent with the impact of an asteroid of sufficient size (6 to 12 miles wide) to cause the global disruptions. Regardless of the true cause of the K-T event, it is fortunate that such impacts are presently believed to happen only about once every 100 million years APOD: October 12, 1997 - Impact ! 65 Million Years Ago Explanation: What killed the dinosaurs ? Their sudden disappearance 65 million years ago, along with about 70 percent of all species then living on Earth, is known as the K-T event (Cretaceous-Tertiary Mass Extinction event). Geologists and paleontologists often entertain the idea of a large asteroid or comet impacting the Earth as the culprit. Besides the firestorms, tidal waves, earthquakes, and hurricane winds such an impact would generate, the debris thrown into the atmosphere would have a serious global environmental impact -- creating extended periods of darkness, low temperatures, and acid rains. In 1990, dramatic support for this theory came from cosmochemist Alan Hildebrand's revelation of a 65 million year old, 112 mile wide ring structure still detectable under layers of sediment in the Yucatan Peninsula region of Mexico. The outlines of the structure, called the Chicxulub crater (named for a local village), are visible in the above representation of gravity and magnetic field data from the region . In addition to having the right age, the crater is consistent with the impact of an asteroid of sufficient size (6 to 12 miles wide) to cause the global disruptions. Regardless of the true cause of the K-T event, it is fortunate that such impacts are presently believed to happen only about once every 100 million years ! APOD: June 4, 1996 - Impact ! 65 Million Years Ago Explanation: What killed the dinosaurs ? Their sudden disappearance 65 million years ago, along with about 70 percent of all species then living on Earth, is known as the K-T event (Cretaceous-Tertiary Mass Extinction event). Geologists and paleontologists often entertain the idea of a large asteroid or comet impacting the Earth as the culprit. Besides the firestorms, tidal waves, earthquakes, and hurricane winds such an impact would generate, the debris thrown into the atmosphere would have a serious global environmental impact -- creating extended periods of darkness, low temperatures, and acid rains. In 1990, dramatic support for this theory came from cosmochemist Alan Hildebrand's revelation of a 65 million year old, 112 mile wide ring structure still detectable under layers of sediment in the Yucatan Peninsula region of Mexico. The outlines of the structure, called the Chicxulub crater (named for a local village), are visible in the above representation of gravity and magnetic field data from the region . In addition to having the right age, the crater is consistent with the impact of an asteroid of sufficient size (6 to 12 miles wide) to cause the global disruptions. Regardless of the true cause of the K-T event, it is fortunate that such impacts are presently believed to happen only about once every 100 million years !
- The classic battle of Tyrannosaurus versus Triceratops is staged again, but this time against a backdrop of impending doom. In the midst of the attack a rain of deadly asteroids heralds the end of the Cretaceous period and the last days of the dinosaurs.
- Apod 99-06-10 APOD: June 10, 1999 - Mjølnir : Impact Crater Explanation: The stark surface of Earth's moon is pocked with large craters, records of a history of fierce bombardment by the solar system's formative debris. It may be difficult to imagine, but nearby planet Earth itself has endured a similar cosmic pounding, though oceans, weathering, and geological activity have removed or hidden many of the telltale scars. For example, this false color image produced from seismic data shows a recently discovered ringed structure about 24 miles wide on the floor of the Barents Sea . It is most probably the result of the impact, roughly 150 million years ago, of a mile or so wide asteroid-like body. Estimates indicate that the energy released in the impact could have been as high as a million megatons of TNT, resulting in immense earthquakes and tidal waves. Drawing on Norse mythology , the crater has been aptly named Mjølnir - Thor's hammer.
- Artist's depiction of the Chicxulub impact crater. About 2,225 near-Earth objects (NEOs) have been detected, primarily by ground-based optical searches, in the size range between 10 meters and 30 kilometers, out of a total estimated population of about one million; some information about the physical size and composition of these NEOs is available for only 300 objects. The total number of objects a kilometer in diameter or larger, a size that could cause global catastrophe upon Earth impact, is now estimated to range between 900 and 1,230. Credit: NASA
- Apod 96-01-20
- The effects of an asteroid tsunami. Image Credit: space.com
- Explanation: If you wait long enough, a piece of outer space itself will come right to you. As Colby Navarro worked innocently on the computer , a rock from space crashed through the roof, struck the printer, banged off the wall, and came to rest near the filing cabinet. This occurred around midnight on March 26 in Park Forest, Illinois , USA , near Chicago . The meteorite , measuring about 10 cm across, was one of several that fell near Chicago that day as part of a tremendous fireball . Pictured above is the resulting hole in the ceiling, while the inset image shows the wall dent and the meteorite itself. Although the vast majority of meteors is much smaller and burn up in the Earth's atmosphere , the average homeowner should expect to repair direct meteor damage every hundred million years.
- Meteor Shower Scary, Stunning & 'Kind Of Exciting' Scientists Call For All Meteor Fragments POSTED: 11:47 a.m. CST March 27, 2003 UPDATED: 10:09 a.m. CST March 28, 2003 CHICAGO -- A flash in the sky and the rumbling sounds of a faraway explosion alerted hundreds of south suburban residents Wednesday night. Reporting those details to authorities, callers flooded police departments, fire departments and various television stations overnight. NBC5's Kim Vatis, reporting from Park Forest, said it turned out to be a meteor shower "that forced a shower of panic calls" to authorities all over the Midwest. In Park Forest, some people who were in their living rooms watching war coverage, thought the United States was under attack with the amazing light show produced by the meteors. It started with a blast of light and a thunderous sound, witnesses told Vatis. Then, chunks of meteorites dropped from the sky. One of the larger segments fell through the roof of a family home and into the bedroom where a young boy was sleeping. "Then all the sudden a big rock came down, right through that hole there," Noe Garza said, pointing to the hole through which one could see the branches of a nearby tree. "It happened too quick. I didn't know what to think and now I'm thinking, afterwards, you know? Wow." SLIDESHOW: Meteor Shower , Park Forest Vatis said that the force of the meteor not only ripped through the roof and ceiling of the house, but it shattered the window, ricocheted off the windowsill and struck the mirrored closet door on the other side of the room. "I don't think anyone's going to believe me," said the man's son, explaining why he was bringing a small bag of fragments to school with him. Roberta Garza laughed as she showed Vatis where a meteor had gone through the plate glass of her home. "It's kind of exciting, I guess," she said. "Where's my insurance agent," quipped her husband nearby. Numerous homes and cars in Park Forest were slightly damaged, Vatis said. The light show itself was overwhelming, witnesses said, and in this time of war, particularly frightening. "I saw an unusually bright flash of light that seemed to be coming from the west. It lasted about 10 seconds and then, all the sudden, it was like instant daylight," said Officer Bob Boyle or the Park Forest police. "At first I thought it was gunfire and then it sounded like thunder, and then it rattled everything," another officer added. Vatis said local scientists are now in a frenzy, saying that the meteorites predate earth and create a celestial light show as they penetrate the earth's atmosphere. The energy locked up in the object itself hitting the atmosphere ... releases it in the form of heat. It's an explosion of light," explained Paul Sipiera, a meteorite researcher. Scientists are urging people to turn over all fragments of the meteors they find, as study of them could help explain the origin of the solar system. This is the ninth meteor shower recorded in Illinois, Vatis said, the first one being recorded in 1928. Copyright 2003 by NBC5.com . All rights reserved. This material may not be published, broadcast, rewritten or redistributed