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Jupiter's Natural Satellites

Jupiter's natural satellites

Jupiter has 63 known natural satellites.

Discovery of the moons

natural satellite The first moons of Jupiter to be discovered were the large Galilean moons, discovered by Galileo in 1610. An independent discovery by ancient Chinese astronomer Gan De may have occurred in 362 BC. Over the next four centuries after Galileo, nine smaller moons were discovered by ground-based astronomers. The Voyager 1 mission discovered three inner moons in 1979, bringing the total then known to 16 (17 if you count Themisto, which had been found but then lost in 1975). The total rested there until 1999. Since then, researchers using sensitive ground-based detectors have recovered Themisto and found a further 46 tiny moons in long, eccentric, generally retrograde orbits. They average 3 kilometres in diameter, and the largest is barely 9 km across. All of these moons are thought to be captured asteroidal or perhaps cometary bodies, possibly fragmented into several pieces, but very little is actually known about them. The total number of known moons of Jupiter now stands at 63, currently the most of any planet in the solar system. Many additional tiny moons may exist that have not yet been discovered.

The most recent discoveries

On October 6 1999, the Spacewatch programme discovered an asteroid, 1999 UX18. But it was soon realised that this was in fact a new moon of Jupiter, now called Callirrhoe. One year later, between November 23 and December 5, 2000, the team led by Scott S. Sheppard and David C. Jewitt of the University of Hawaii began a systematic search for small irregular moons of Jupiter. The other members of the team included, at various times, Yanga R. Fernández, Eugene A. Magnier, Scott Dahm, Aaron Evans, Henry H. Hsieh, Karen J. Meech, John L. Tonry, David J. Tholen (all from the University of Hawaii), Jan Kleyna (Cambridge University), Brett J. Gladman (University of Toronto), John J. Kavelaars (Hertzberg Institute of Astrophysics), Jean-Marc Petit (Observatoire de Besançon) and Rhiannon Lynne Allen (University of Michigan / University of British Columbia). The team used the world's two largest CCD cameras, mounted on two of the thirteen telescopes atop Mauna Kea in Hawaii: the Subaru (8.3 m diameter) and the Canada-France-Hawaii (3.6 m). The 2000 observations revealed ten new moons, putting the count at 28 (Themisto had been rediscovered at the beginning of 2000). The following year, on December 9-11, 2001, eleven other moons were discovered, bringing the total to 39. The year 2002 bore less fruit, netting only one moon, Arche. However, four months later, between February 5 and 9, 2003, 23 more moons were found, making for a complete sum of 63 moons. References:
- [http://www.ifa.hawaii.edu/~sheppard/sheppardjupiter.pdf David C. Jewitt, Scott S. Sheppard, An abundant population of small irregular satellites around Jupiter, Nature, Vol 423, p. 261, May 2003]
- [http://dosxx.colorado.edu/JUPITER/PDFS/Ch12.pdf David C. Jewitt, Scott S. Sheppard and Carolyn Porco, Jupiter's Outer Satellites and Trojans, Nov 2003]
- [http://www.ifa.hawaii.edu/~sheppard/satellites/jup2003.html New Satellites of Jupiter Discovered in 2003]

Table of known moons

The Jovian moons are listed here by orbital period, from shortest to longest. Moons massive enough for their surfaces to have collapsed into a spheroid are highlighted in purple; these are Galileian moons are comparable in size to the Earth's moon. Irregular (captured) moons are indicated by light grey.
- (1) Computed using the [http://cfa-www.harvard.edu/iau/NatSats/NaturalSatellites.html IAU-MPC Satellites Ephemeris Service] µ value
- (2) Source: [http://sse.jpl.nasa.gov/planets/profile.cfm?Object=Jupiter&Display=Facts JPL/NASA]
- (3) Source (for Themisto outward): IAU-MPC Satellites Ephemeris Service
- (4) Computed from [http://www.hnsky.org/iau-iag.htm IAG Travaux 2001] for Metis through Callisto, IAU-MPC Satellites Ephemeris Service orbital elements for the others

Grouping the moons

The interior groups - the four inner moons and the Galileans - seem natural. Themisto is isolated in space. The Himalia group is "tight", spread over barely 1.4 Gm in semi-major axis and 1.6° in inclination (27.5 ± 0.8°). The eccentricities vary between 0.11 and 0.25. Carpo and S/2003 J 12 are two other isolated cases, and so is S/2003 J 2, the most exterior moon. What is left of the outer retrograde irregular satellites of Jupiter can be grouped into three families, based on shared orbital characteristics and bearing the name of the largest member in each case. These families are clumps in semi-major axis, but also in inclination and in eccentricity. In the two plots below, Carme's group is in orange and Ananke's in yellow. S/2003 J 2 S/2003 J 2 S/2003 J 2 Carme's group is obvious, centered on a = 23 404 Mm; i = 165.2±0.3° and e = 0.238–0.272. Only S/2003 J 10 seems somewhat apart, because of its great eccentricity. Ananke's group is centered on a = 21 276 Mm; i = 149.0±0.5° and e = 0.216–0.244; but its borders are less definite. The eight core members (S/2003 J 16, Mneme, Euanthe, Orthosie, Harpalyke, Praxidike, Thyone, Thelxinoe, Ananke, Iocaste) are well-clumped, but the attribution of the remaining eight members to the group is debatable to varying degrees. Pasiphaë's group, finally, picks up the remainder, with the exception of the moons at the inner and outer limits of the groups (S/2003 J 12 and S/2003 J 2); it is centered on a = 23 624 Mm; i = 151.4±6.9° and e = 0.156–0.432 (note the much larger spreads). If it is real, it must be ancient to explain the dispersion of its membership.

Naming notes

Some asteroids share the same names as moons of Jupiter: 9 Metis, 38 Leda, 52 Europa, 85 Io, 113 Amalthea, 239 Adrastea. A couple of asteroids shared the names of Jovian moons until spelling differences were made permanent by the IAU. Those contrasting pairs are the moon Ganymede and the asteroid 1036 Ganymed; and the moon Callisto and the asteroid 204 Kallisto. The moon Themisto purposely uses a name derived from the longer gentive form of the source of the name for asteroid 24 Themis. Note that the satellites discovered between 1904 and 1951 (Himalia, Elara, Pasiphaë, Sinope, Lysithea, Carme and Ananke) were not officially named until 1975, 24 years after the last satellite was discovered. They were simply known by their Roman numeral designations (Jupiter VI through Jupiter XII). See Naming of natural satellites.

See also


- Saturn's natural satellites
- Uranus' natural satellites
- Neptune's natural satellites
- Pluto's natural satellites
- Timeline of natural satellites
- Naming of natural satellites

External links


- [http://www.ifa.hawaii.edu/~sheppard/satellites/jupsatdata.html Jupiter satellite data]
- [http://www.sfgate.com/cgi-bin/article.cgi?file=/chronicle/archive/2003/05/15/MN286597.DTL&type=science 43 more moons orbiting Jupiter]
- als:Liste der Jupitermonde ja:木星の衛星と環

Jupiter (planet)

Jupiter is the fifth planet from the Sun and by far the largest within our solar system. Some have described the solar system as consisting of the Sun, Jupiter, and assorted debris,; some describe Jupiter as the solar system's vacuum cleaner, due to its immense gravity well. It, and the other gas giants - Saturn, Uranus, and Neptune, are sometimes referred to as "Jovian planets." The Romans named the planet after the Roman god Jupiter (also called Jove). The astronomical symbol for the planet is a stylized representation of the god's lightning bolt. The Chinese, Korean, Japanese, and Vietnamese cultures refer to the planet as the wood star, 木星, based on the Chinese Five Elements (although, curiously enough, through a small telescope, it does somewhat resemble a circular slice of wood in appearance, with the Red Spot being a "knot").

Overview

Jupiter has been known since ancient times and is visible to the naked eye in the night sky. In 1610, Galileo Galilei discovered the four largest moons of Jupiter using a telescope, the first observation of moons other than Earth's. Jupiter is 2.5 times more massive than all the other planets combined, so massive that its barycenter with the Sun actually lies above the Sun's surface (1.068 solar radii from the Sun's center). It is 318 times more massive than Earth, with a diameter 11 times that of Earth, and with a volume 1300 times that of Earth. As impressive as it is, extrasolar planets have been discovered with much greater masses. There is no clear-cut definition of what distinguishes a large and massive planet such as Jupiter from a brown dwarf star, although the latter possesses rather specific spectral lines. Jupiter is thought to have about as large a diameter as a planet of its composition can; adding extra mass would result in further gravitational compression, in theory leading to stellar ignition. This has led some astronomers to term it a "failed star", although Jupiter would need to be about seventy times as massive to become a star. brown dwarf Jupiter also has the fastest rotation rate of any planet within the solar system, making a complete revolution on its axis in slightly less than ten hours, which results in a flattening easily seen through an Earth-based amateur telescope. Its best known feature is probably the Great Red Spot, a storm larger than Earth which was first observed by Galileo four centuries ago. Indeed, mathematical models suggest that the storm is a permanent feature of the planet. Jupiter is perpetually covered with a layer of clouds, and may not have any solid surface. Jupiter is usually the fourth brightest object in the sky (after the Sun, the Moon and Venus; however at times Mars appears brighter than Jupiter, while at others Jupiter appears brighter than Venus). It has been known since ancient times. Galileo Galilei's discovery, in 1610, of Jupiter's four large moons Io, Europa, Ganymede and Callisto (now known as the Galilean moons) was the first discovery of a celestial motion not apparently centered on the Earth. It was a major point in favor of Copernicus' heliocentric theory of the motions of the planets; Galileo's outspoken support of the Copernican theory got him in trouble with the Inquisition.

Physical characteristics

Planetary composition

Jupiter is composed of a relatively small rocky core, surrounded by metallic hydrogen, surrounded by liquid hydrogen, which is surrounded by gaseous hydrogen. There is no clear boundary or surface between these different phases of hydrogen; the conditions blend smoothly from gas to liquid as one descends.

Atmosphere

gas and a passing white oval.]] Jupiter's atmosphere is composed of ~81% hydrogen and ~18% helium by number of atoms. The atmosphere is ~75%/24% by mass; with ~1% of the mass accounted for by other substances - the interior contains denser materials such that the distribution is ~71%/24%/5%. The atmosphere contains trace amounts of methane, water vapour, ammonia, and "rock". There are also traces of carbon, ethane, hydrogen sulfide, neon, oxygen, phosphine, and sulfur. The outermost layer of the atmosphere contains crystals of frozen ammonia. This atmospheric composition is very close to the composition of the solar nebula. Saturn has a similar composition, but Uranus and Neptune have much less hydrogen and helium. Jupiter's upper atmosphere undergoes differential rotation, an effect first noticed by Giovanni Cassini (1690). The rotation of Jupiter's polar atmosphere is ~5 minutes longer than that of the equatorial atmosphere. In addition, bands of clouds of different latitudes, known as tropical regions flow in opposing directions on the prevailing winds. The interactions of these conflicting circulation patterns cause storms and turbulence. Wind speeds of 600 km/h are not uncommon. A particularly violent storm, about three times Earth's diameter, is known as the Great Red Spot, and has persisted through more than three centuries of human observation. The only spacecraft to have descended into Jupiter's atmosphere to take scientific measurements is the Galileo probe (see Galileo mission).

Planetary rings

Jupiter has a faint planetary ring system composed of smoke-like dust particles knocked from its moons by meteor impacts. The main ring is made of dust from the satellites Adrastea and Metis. Two wide gossamer rings encircle the main ring, originating from Thebe and Amalthea. There is also an extremely tenuous and distant outer ring that circles Jupiter backwards. Its origin is uncertain, but this outer ring might be made of captured interplanetary dust.

Magnetosphere

Jupiter has a very large and powerful magnetosphere. In fact, if you could see Jupiter's magnetic field from Earth, it would appear five times as large as the full moon in the sky despite being so much farther away. This magnetic field collects a large flux of particle radiation in Jupiter's radiation belts, as well as producing a dramatic gas torus and flux tube associated with Io. Jupiter's magnetosphere is the largest planetary structure in the solar system. The Pioneer probes confirmed that Jupiter's enormous magnetic field is 10 times stronger than Earth's and contains 20,000 times as much energy. The sensitive instruments aboard found that the Jovian magnetic field's "north" magnetic pole is at the planet’s geographic south pole, with the axis of the magnetic field tilted 11 degrees from the Jovian rotation axis and offset from the center of Jupiter in a manner similar to the axis of the Earth's field. The Pioneers measured the bow shock of the Jovian magnetosphere to the width of 26 million kilometres (16 million miles), with the magnetic tail extending beyond Saturn’s orbit. The data showed that the magnetic field fluctuates rapidly in size on the sunward side of Jupiter because of pressure variations in the solar wind, an effect studied in further detail by the two Voyager spacecraft. It was also discovered that streams of high-energy atomic particles are ejected from the Jovian magnetosphere and travel as far as the orbit of the Earth. Energetic protons were found and measured in the Jovian radiation belt and electric currents were detected flowing between Jupiter and some of its moons, particularly Io.

Appearance

Source: [http://www.calsky.com/cs.cgi/Planets/6/3?obs=75910112501970 The Calculated Sky]

Exploration of Jupiter

A number of probes have visited Jupiter.

Pioneer flyby missions

Pioneer 10 flew past Jupiter in December of 1973, followed by Pioneer 11 exactly one year later. They provided important new data about Jupiter's magnetosphere, and took some low-resolution photographs of the planet.

Voyager flyby missions

Pioneer 11 Voyager 1 flew by in March 1979 followed by Voyager 2 in July of the same year. The Voyagers vastly improved our understanding of the Galilean moons and discovered Jupiter's rings. They also took the first close up images of the planet's atmosphere.

Ulysses flyby mission

In February 1992, Ulysses solar probe performed a flyby of Jupiter at a distance of 900,000 km (6.3 Jovian radii). The flyby was required to attain a polar orbit around the Sun. The probe conducted studies on Jupiter's magnetosphere. Since there are no cameras onboard the probe, no images were taken. In February 2004, the probe came again in the vicinity of Jupiter. This time distance was much greater, about 240 million km.

Galileo mission

So far the only spacecraft to orbit Jupiter is the Galileo orbiter, which went into orbit around Jupiter in December 7, 1995. It orbited the planet for over seven years and conducted multiple flybys of all of the Galilean moons and Amalthea. The spacecraft also witnessed the impact of Comet Shoemaker-Levy 9 into Jupiter as it approached the planet in 1994, giving a unique vantage point for this spectacular event. However, the information gained about the Jovian system from the Galileo mission was limited by the failed deployment of its high-gain radio transmitting antenna. 1994 An atmospheric probe was released from the spacecraft in July, 1995. The probe entered the planet's atmosphere in December 7, 1995. It parachuted through 150 km of the atmosphere, collecting data for 57.6 minutes, before being crushed by the extreme pressure to which it was subjected. It would have melted and vaporized shortly thereafter. The Galileo orbiter itself experienced a more rapid version of the same fate when it was deliberately steered into the planet on September 21, 2003 at a speed of over 50 km/s, in order to avoid any possibility of it crashing into and possibly contaminating Europa, one of the Jovian moons.

Cassini flyby mission

In 2000, the Cassini probe, en route to Saturn, flew by Jupiter and provided some of the highest-resolution images ever made of the planet.

Future probes

NASA is planning a mission to study Jupiter in detail from a polar orbit. Named Juno, the spacecraft is planned to launch by 2010. After the discovery of a liquid ocean on Jupiter's moon Europa, there has been great interest to study the icy moons in detail. A mission proposed by NASA was dedicated to study them. The JIMO (Jupiter Icy Moons Orbiter) was expected to be launched sometime after 2012. However, the mission was deemed too ambitious and its funding was cancelled. In 2007, Jupiter will also be briefly visited by the New Horizons probe, en route to Pluto.

Natural satellites

Pluto, Ganymede, Europa and Io.]] Jupiter has at least 63 moons. For a complete listing of these moons, please see Jupiter's natural satellites. For a timeline of their discovery dates, see Timeline of natural satellites. The four large moons, known as the "Galilean moons", are Io, Europa, Ganymede and Callisto.

Galilean moons

The orbits of Io, Europa, and Ganymede, the largest moon in the solar system, form a pattern known as a Laplace resonance; for every four orbits that Io makes around Jupiter, Europa makes exactly two orbits and Ganymede makes exactly one. This resonance causes the gravitational effects of the three moons to distort their orbits into elliptical shapes, since each moon receives an extra tug from its neighbors at the same point in every orbit it makes. gravitational The tidal force from Jupiter, on the other hand, works to circularize their orbits. This constant tug of war causes regular flexing of the three moons' shapes, Jupiter's gravity stretches the moons more strongly during the portion of their orbits that are closest to it and allowing them to spring back to more spherical shapes when they're farther away. This flexing causes tidal heating of the three moons' cores. This is seen most dramatically in Io's extraordinary volcanic activity, and to a somewhat less dramatic extent in the geologically young surface of Europa indicating recent resurfacing.

Classification of Jupiter's moons

Before the discoveries of the Voyager missions, Jupiter's moons were arranged neatly into four groups of four. Since then, the large number of new small outer moons has complicated this picture. There are now thought to be six main groups, although some are more distinct than others. A basic division is between the eight inner regular moons with nearly circular orbits near the plane of Jupiter's equator, which are believed to have formed with Jupiter, and an unknown number of small irregular moons, with elliptical and inclined orbits, which are believed to be captured asteroids or fragments of captured asteroids. tidal force.]] #Regular moons ##The inner group of four small moons all have diameters of less than 200 km, orbit at radii less than 200,000 km, and have orbital inclinations of less than half a degree. ##The four Galilean moons were all discovered by Galileo Galilei, orbit between 400,000 and 2,000,000 km, and include some of the largest moons in the solar system. #Irregular moons ##Themisto is in a group of its own, orbiting halfway between the Galilean moons and the next group. ##The Himalia group is a tightly clustered group of moons with orbits around 11-12,000,000 km from Jupiter. ##Carpo is another isolated case; at the inner edge of the Ananke group, it revolves in the direct sense. ##The Ananke group is a group with rather indistinct borders, averaging 21,276,000 km from Jupiter with an average inclination of 149 degrees. ##The Carme group is a fairly distinct group that averages 23,404,000 km from Jupiter with an average inclination of 165 degrees. ##The Pasiphaë group is a dispersed and only vaguely distinct group that covers all the outermost moons. It is thought that the groups of outer moons may each have a common origin, perhaps as a larger moon or captured body that broke up.

Life on Jupiter

It is considered highly unlikely that there is any life on Jupiter, as there is little to no water in the atmosphere and any solid surface Jupiter would be under extraordinary pressures. However, in 1976, before the Voyager missions, Carl Sagan hypothesized (with Edwin E. Salpeter) that ammonia-based life could evolve in Jupiter's upper atmosphere. Sagan and Salpeter based this hypothesis on the ecology of terrestrial seas which have simple photosynthetic plankton at the top level, fish at lower levels feeding on these creatures, and marine predators which hunt the fish. The Jovian equivalents Sagan and Saltpeter hypothesized were "sinkers," "floaters," and "hunters." The "floaters" would be giant bags of gas functioning along the lines of hot air balloons, using their own metabolism (feeding off sunlight and free molecules) to keep their gas warm. The "hunters" would be almost squid-like creatures, using jets of gas to propel themselves into "floaters" and consume them. [http://www.daviddarling.info/encyclopedia/J/Jupiterlife.html] These ideas are only hypotheses and there is currently no way to prove or disprove them.

Trojan asteroids

In addition to its moons, Jupiter's gravitational field controls numerous asteroids which have settled into the Lagrangian points preceding and following Jupiter in its orbit around the sun. These are known as the Trojan asteroids, and are divided into Greek and Trojan "camps" to commemorate the Iliad. The first of these, 588 Achilles, was discovered by Max Wolf in 1906; since then hundreds more have been discovered. The largest is 624 Hektor.

Cometary impact

624 Hektor During the period July 16 to July 22, 1994, over twenty fragments from the comet Shoemaker-Levy 9 hit Jupiter's southern hemisphere, providing the first direct observation of a collision between two solar system objects. It is thought that due to Jupiter's large mass and location near the inner solar system it receives the most frequent comet impacts of the solar system's planets.

Jupiter in fiction and film


- In Voltaire's Micromégas (1752), the eponymous hero and his Saturnian companion stop on Jupiter for a year, where they "learned some very remarkable secrets".
- In H. P. Lovecraft's Cthulhu Mythos (1928–...), Jupiter was the one-time home of the flying polyps.
- In the Doctor Who (1963–...) story "Revenge of the Cybermen", Jupiter is the setting for the Nerva Beacon, a fictional space station that monitors its fictional new moon (Voga - the Planet of Gold) which once more brings the Cybermen into our Solar System.
- In the Star Trek universe (1966–...), Jupiter is home to Jupiter Station.
- Jupiter is the setting of Stanley Kubrick's classic film 2001: A Space Odyssey (1968), although the novel of the same name by Sir Arthur C. Clarke is set in the Saturnian system instead. In both the book and the film of the sequel, 2010: Odyssey Two (1984), fictional technology converts Jupiter into a star by increasing the density of its core.
- In Piers Anthony's Bio of A Space Tyrant series (1983–2001), Jupiter is rendered into an analogue of North America. The moons are the Caribbean (and possibly Central America as well), Jupiter itself is inhabited by floating cities in its atmosphere to represent the United States, and the Red Spot represents Mexico.
- The novels of Kim Stanley Robinson, including The Memory of Whiteness (1985), Green Mars (1993) and Blue Mars (1996) depict numerous ideas about the future colonization of Jupiter, although they focus more on the moons than on the planet itself.
- Both Arthur C. Clarke's novella A Meeting with Medusa (1988) and his novel 2010 depict journeys into the depths of Jupiter's atmosphere, where vast, city-sized floating life-forms have evolved.
- In the anime Gunbuster (1988), Jupiter is used to create the black hole bomb, a massive weapon larger than a small planet, and capable of destroying part of a galaxy. (In fact, a Jupiter-mass black hole would be barely 6 m across, and no more of a threat to the Galaxy than it is right now)
- The role-playing game Jovian Chronicles (1992) features a solar nation, the Jovian Confederacy, in a series of space colony cylinders called "Gray Viarium" colonies around Jupiter.
- The plot of the anime Martian Successor Nadesico (1996) revolves around a mysterious invasion force based on Jupiter, named the "Jovian Lizards", or simply the "Jovians", and the attempts of Earth's forces, and specifically the ship Nadesico, to subdue this invasion.
- Jupiter is an important location in The Night's Dawn Trilogy (1996–1999) by Peter F. Hamilton. This is where the first Bitek habitat was germinated and Edenism began.
- In the anime Cowboy Bebop (1998), various episodes take place on Jupiter's moons. In, "Mushroom Samba",the crew was on its way to Europa, but had to land on Io. The two part "Jupiter Jazz" episodes takes part on Callisto, and "Ganymede Elegy", obviously takes place on Ganymede.
- In the anime Bishoujo Senshi Sailor Moon (1992), Sailor Jupiter is a soldier representing the planet. Since her mythology character (Romans' Jupiter and Greek's Zeus) is a male, her character appears somewhat tomboyish, and more of a born-leader. Also in mythology, Zeus's weapon involves lightning, Jupiter's attacks are also based on the same element (e.g. Jupiter Lightning Blast). Her image colour is green.
- The PlayStation 2 video game Zone of the Enders (2001) takes place in a colony orbiting Jupiter. Zone of the Enders: The 2nd Runner begins on the moon Callisto.
- Ben Bova's novel Jupiter (2001) also features a journey into Jupiter's clouds and the discovery of life there.
- In the massively multiplayer online role-playing game (MMORPG) Earth and Beyond (2002), the Jupiter system is colonized by the explorer race of the Jenquai. Jove City rests in orbit around Jupiter, and was the second most populated station in the known galaxy before being devastated by the Progen Warriors.
- The anime Planetes (2003) features a planned seven year trip to explore Jupiter and its moons, using a ship powered by a Tandem Mirror Engine.
- In Arthur C. Clarke's Space Odyssey Series, Jupiter was renamed Lucifer after its transformation into Earth's second sun. William Milton Cooper's book Behold a Pale Horse described a secret illuminati plan to detonate the planet by means of the Cassini-Huygens space probe.
- In the Dragon Ball Z manga series created by Akira Toriyama, female character Bulma Briefs and Earth Kami assitant Mr.Popo reach Jupiter in less than a minute using Kami's spaceship, which they needed to reach the Planet Namek, which was impossible to reach with the technology available at that moment in the series. One month later Bulma's father completes a spaceship model capable of making the journey!

Jupiter and Internet conspiracists

Although the theory of the intentional detonation of Jupiter predates the internet, the web spawned at least one theory of its own. On October 19, 2003 a black spot was photographed on Jupiter by Belgian astronomer Olivier Meeckers [http://www.space.com/scienceastronomy/jupiter_dark_spot_031023.html]. Although not an unusual occurrence, this one caught the fancy of some science fiction fans and conspiracy theorists, who went as far as speculating that the spot was evidence of nuclear activity on Jupiter, caused by Galileo's plunge into the planet a month prior [http://www.enterprisemission.com/NukingJupiter.html]. Galileo carried about 15.6 kg [http://www.resa.net/nasa/engineer.htm] of plutonium-238 as its power source, in the form of 144 pellets of plutonium dioxide, a ceramic [http://www2.jpl.nasa.gov/galileo/messenger/oldmess/RTG.html] [http://www2.jpl.nasa.gov/galileo/faqpow.html]. The individual pellets (which would be expected to separate during entry) initially contained about 108 grams of 238Pu each (about 10% would have decayed away by the time Galileo entered Jupiter), and are short of the required critical mass by a factor of about 100 [http://sti.srs.gov/fulltext/ms9900313/ms9900313.html].

See also


- Jupiter in astrology
- Jupiter in Mythology

References


- Bagenal, F. & Dowling, T. E. & McKinnon, W. B. (Eds.). (2004). Jupiter: The planet, satellites, and magnetosphere. Cambridge: Cambridge University Press.
-

External links


- [http://nssdc.gsfc.nasa.gov/planetary/factsheet/jupiterfact.html NASA's Jupiter fact sheet]
- [http://www.vias.org/spacetrip/jupiter_1.html A Trip Into Space] Data and photos on Jupiter
- [http://pages.preferred.com/%7Etedstryk/innersat.html Jupiter's Inner Moons]
- [http://www.ibiblio.org//e-notes/VRML/Globe/Globe.htm 3D VRML Jupiter globe] and it's satellites Io, Callisto, Europa and Ganymede
(moon navigator) | Jupiter | Metis | ...

- als:Jupiter (Planet) ko:목성 ms:Musytari ja:木星 simple:Jupiter (planet) th:ดาวพฤหัสบดี

Galileo Galilei

Galileo Galilei (Pisa, February 15 1564 – Arcetri, January 8 1642), was an Italian physicist, astronomer, and philosopher who is closely associated with the scientific revolution. His achievements include improvements to the telescope, a variety of astronomical observations, the first law of motion and the second law of motion, and effective support for Copernicanism. He has been referred to as the "father of modern astronomy," as the "father of modern physics," and as "father of science." His experimental work is widely considered complementary to the writings of Francis Bacon in establishing the modern scientific method. Galileo's career coincided with that of Johannes Kepler. The work of Galileo is considered to be a significant break from that of Aristotle. In addition, his conflict with the Roman Catholic Church is taken as a major early example of the conflict of authority and freedom of thought, particularly with science, in Western society.

Galileo's Family & Early Careers

Galileo was born in Pisa, in the Tuscan region of Italy, the son of Vincenzo Galilei, a mathematician and musician born in Florence in 1520, and Giulia Ammannati, born in Pescia and married in 1563. Galileo was their first child. Although a devout Catholic, Galileo fathered three children out of wedlock. All were the children of Galileo and Marina Gamba. Because of their illegitimate birth, both girls were sent to the convent of San Matteo in Arcetri at early ages.
- Virginia (b. 1600) who took the name Maria Celeste upon entering a convent. Galileo's eldest child, the most beloved, and inherited her father's sharp mind. She died in 1634 on April second. She is buried with Galileo at the Basilica di Santa Croce di Firenze.
- Livia (b. 1601) took the name Suor Arcangela. Was sickly for most of her life at the convent.
- Vincenzio (b. 1606) was later legitimized and married Sestilia Bocchineri He was home schooled at a very young age. After that he attended the University of Pisa, but was forced to cease his study there for financial reasons. However, he was offered a position on its faculty in 1589 and taught mathematics. Soon after, he moved to the University of Padua, and served on its faculty teaching geometry, mechanics, and astronomy until 1610. During this time he explored science and made many landmark discoveries.

Experimental science

In the pantheon of the scientific revolution, Galileo takes a high position because of his pioneering use of quantitative experiments with results analyzed mathematically. There was no tradition of such methods in European thought at that time; the great experimentalist who immediately preceded Galileo, William Gilbert, did not use a quantitative approach. However, Galileo's father, Vincenzo Galilei, had performed experiments in which he discovered what may be the oldest known non-linear relation in physics, between the tension and the pitch of a stretched string. Galileo also contributed to the rejection of blind allegiance to authority (like the Church) or other thinkers (such as Aristotle) in matters of science and to the separation of science from philosophy or religion. These are the primary justifications for his description as the "father of science." In the 20th century some authorities challenged the reality of Galileo's experiments, in particular the distinguished French historian of science Alexandre Koyré. The experiments reported in Two New Sciences to determine the law of acceleration of falling bodies, for instance, required accurate measurements of time, which appeared to be impossible with the technology of the 1600s. According to Koyré, the law was arrived at deductively, and the experiments were merely illustrative thought experiments. Later research, however, has validated the experiments. The experiments on falling bodies (actually rolling balls) were replicated using the methods described by Galileo (Settle, 1961), and the precision of the results was consistent with Galileo's report. Later research into Galileo's unpublished working papers from as early as 1604 clearly showed the reality of the experiments and even indicated the particular results that led to the time-squared law (Drake, 1973).

Astronomy

Contributions

Although the popular idea of Galileo inventing the telescope is inaccurate, he was one of the first people to use the telescope to observe the sky, and for a time was one of very few people able to make a good enough telescope for the purpose. Based on sketchy descriptions of telescopes invented in the Netherlands in 1608, Galileo made one with about 8x magnification, and then made improved models up to about 20x. On August 25, 1609, he demonstrated his first telescope to Venetian lawmakers. His work on the device also made for a profitable sideline with merchants who found it useful for their shipping businesses. He published his initial telescopic astronomical observations in March 1610 in a short treatise entitled Sidereus Nuncius (Sidereal Messenger). Sidereus Nuncius. This observation upset the notion that all celestial bodies must revolve around the Earth. Galileo published a full description in Sidereus Nuncius in March 1610.]] On January 7, 1610 Galileo discovered three of Jupiter's four largest satellites (moons): Io, Europa, and Callisto. Ganymede he discovered four nights later. He determined that these moons were orbiting the planet since they would appear and disappear; something he attributed to their movement behind Jupiter. He made additional observations of them in 1620. Later astronomers overruled Galileo's naming of these objects, changing his Medicean stars to Galilean satellites. The demonstration that a planet had smaller planets orbiting it was problematic for the orderly, comprehensive picture of the geocentric model of the universe, in which everything circled around the Earth. Galileo noted that Venus exhibited a full set of phases like the Moon. The heliocentric model of the solar system developed by Copernicus predicted that all phases would be visible since the orbit of Venus around the Sun would cause its illuminated hemisphere to face the Earth when it was on the opposite side of the Sun and to face away from the Earth when it was on the Earth-side of the Sun. By contrast, the geocentric model of Ptolemy predicted that only crescent and new phases would be seen, since Venus was thought to remain between the Sun and Earth during its orbit around the Earth. Galileo's observation of the phases of Venus proved that Venus orbited the Sun and lent support to (but did not prove) the heliocentric model. Galileo was one of the first Europeans to observe sunspots, although there is evidence that Chinese astronomers had done so before. The very existence of sunspots showed another difficulty with the unchanging perfection of the heavens as assumed in the older philosophy. And the annual variations in their motions, first noticed by Francesco Sizzi, presented great difficulties for either the geocentric system or that of Tycho Brahe. A dispute over priority in the discovery of sunspots led to a long and bitter feud with Christoph Scheiner; in fact, there can be little doubt that both of them were beaten by David Fabricius and his son Johannes. He was the first to report lunar mountains and craters, whose existence he deduced from the patterns of light and shadow on the Moon's surface. He even estimated the mountains' heights from these observations. This led him to the conclusion that the Moon was "rough and uneven, and just like the surface of the Earth itself", and not a perfect sphere as Aristotle had claimed. Galileo observed the Milky Way, previously believed to be nebulous, and found it to be a multitude of stars, packed so densely that they appeared to be clouds from Earth. He also located many other stars too distant to be visible with the naked eye. Galileo observed the planet Neptune in 1612, but did not realize that it was a planet and took no particular notice of it. It appears in his notebooks as one of many unremarkable dim stars.

Modern claims of scientific errors and misconduct

Although Galileo is generally considered one of the first modern scientists, as evidenced by his position in the sunspot controversy, he is often said to have arrogantly considered himself to be the sole-propietor of the discoveries in astronomy. Furthermore, he never accepted Kepler's elliptical orbits for the planets, holding to the circular orbits of Copernicus, which still employed epicycles to account for irregularities in planetary motions. Concerning his theory on tides, Galileo attributed them to momentum despite his great knowledge of the ideas of relative motion and Kepler's better theories using the Moon as the cause. (Neither of these great scientists, however, had a workable physical theory of tides; this had to wait for the work of Newton) Galileo stated in his Dialogue that, if the Earth spins on its axis and is traveling at a certain speed around the Sun, parts of the Earth must travel "faster" at night and "slower" during the day. This, of course, is true in the Sun's frame of reference; but it is by no means adequate to explain the tides. Many commentators consider that Galileo developed this position simply to justify his own opinion because the theory was not based on any real scientific observations because if his theory was correct, there would be only one high tide per day and it would happen at noon. The fact that there are two daily high tides at Venice instead of one, and that they travel around the clock, Galileo and his contemporaries knew, but he dismissed as due to several secondary causes, such as the shape of the sea, its depth, and other things. Against the imputation that Galileo was guilty of some kind of deceit in making these arguments one may take the position of Albert Einstein, as one who had done original work in physics, that Galileo developed his "fascinating arguments" and accepted them too uncritically out of a desire for a physical proof of the motion of the Earth (Einstein, 1952)

Physics

Galileo's theoretical and experimental work on the motions of bodies, along with the largely independent work of Kepler and René Descartes, was a precursor of the Classical mechanics developed by Sir Isaac Newton. He was a pioneer, at least in the European tradition, in performing rigorous experiments and insisting on a mathematical description of the laws of nature. One of the most famous stories about Galileo is that he dropped balls of different masses from the Leaning Tower of Pisa to demonstrate that their time of descent was independent of their mass (excluding the limited effect of air resistance). This was contrary to what Aristotle had taught: that heavy objects fall faster than lighter ones, in direct proportion to weight. Though the story of the tower first appeared in a biography by Galileo's pupil Vincenzo Viviani, it is not now generally accepted as true. However, Galileo did perform experiments involving rolling balls down inclined planes, which proved the same thing: falling or rolling objects (rolling is a slower version of falling, as long as the distribution of mass in the objects is the same) are accelerated independently of their mass. He determined the correct mathematical law for acceleration: the total distance covered, starting from rest, is proportional to the square of the time (This law is regarded as a predecessor to the many later scientific laws expressed in mathematical form.). He also concluded that objects retain their velocity unless a force -- often friction -- acts upon them, refuting the accepted Aristotelian hypothesis that objects "naturally" slow down and stop unless a force acts upon them. Galileo's Principle of Inertia stated: "A body moving on a level surface will continue in the same direction at constant speed unless disturbed." This principle was incorporated into Newton's laws of motion (1st law). Newton's laws of motion Galileo also noted that a pendulum's swings always take the same amount of time, independently of the amplitude. The story goes that he came to this conclusion by watching the swings of the bronze chandelier in the cathedral of Pisa, using his pulse to time it. While Galileo believed this equality of period to be exact, it is only an approximation appropriate to small amplitudes. It is good enough to regulate a clock, however, as Galileo may have been the first to realize. (See Technology below) In the early 1600s, Galileo and an assistant tried to measure the speed of light. They stood on different hilltops, each holding a shuttered lantern. Galileo would open his shutter, and, as soon as his assistant saw the flash, he would open his shutter. At a distance of less than a mile, Galileo could detect no delay in the round-trip time greater than when he and the assistant were only a few yards apart. While he could reach no conclusion on whether light propagated instantaneously, he recognized that the distance between the hilltops was perhaps too small for a good measurement. Galileo is lesser known for, yet still credited with being one of the first to understand sound frequency. After scraping a chisel at different speeds, he linked the pitch of sound to the spacing of the chisel's skips (frequency). In his 1632 Dialogue Galileo presented a physical theory to account for tides, based on the motion of the Earth. If correct, this would have been a strong argument for the reality of the Earth's motion. (The original title for the book, in fact, described it as a dialogue on the tides; the reference to tides was removed by order of the Inquisition.) His theory gave the first insight into the importance of the shapes of ocean basins in the size and timing of tides; he correctly accounted, for instance, for the negligible tides halfway along the Adriatic Sea compared to those at the ends. As a general account of the cause of tides, however, his theory was a failure. Kepler and others correctly associated the Moon with an influence over the tides, based on empirical data; a proper physical theory of the tides, however, was not available until Newton. Galileo also put forward the basic principle of relativity, that the laws of physics are the same in any system that is moving at a constant speed in a straight line, regardless of its particular speed or direction. Hence, there is no absolute motion or absolute rest. This principle provided the basic framework for Newton's laws of motion and Einstein's theory of relativity.

Mathematics

While Galileo's application of mathematics to experimental physics was innovative, his mathematical methods were the standard ones of the day. The analyses and proofs relied heavily on the Eudoxian theory of proportion, as set forth in the fifth book of Euclid's Elements. This theory had become available only a century before, thanks to accurate translations by Tartaglia and others; but by the end of Galileo's life it was being superseded by the algebraic methods of Descartes, which a modern finds incomparably easier to follow. Galileo produced one piece of original and even prophetic work in mathematics: Galileo's paradox, which shows that there are as many perfect squares as there are whole numbers, even though most numbers are not perfect squares. Such seeming contradictions were brought under control 250 years later in the work of Georg Cantor.

Technology

Galileo made a few contributions to what we now call technology as distinct from pure physics, and suggested others. This is not the same distinction as made by Aristotle, who would have considered all Galileo's physics as techne or useful knowledge, as opposed to episteme, or philosophical investigation into the causes of things. In 1595–1598, Galileo devised and improved a "Geometric and Military Compass" suitable for use by gunners and surveyors. This expanded on earlier instruments designed by Niccolo Tartaglia and Guidobaldo del Monte. For gunners, it offered, in addition to a new and safer way of elevating cannons accurately, a way of quickly computing the charge of gunpowder for cannonballs of different sizes and materials. As a geometric instrument, it enabled the construction of any regular polygon, computation of the area of any polygon or circular sector, and a variety of other calculations. About 1606–1607 (or possibly earlier), Galileo made a thermometer, using the expansion and contraction of air in a bulb to move water in an attached tube. In 1609, Galileo was among the first to use a refracting telescope as an instrument to observe stars, planets or moons. In 1610, he used a telescope as a compound microscope, and he made improved microscopes in 1623 and after. This appears to be the first clearly documented use of the compound microscope. In 1612, having determined the orbital periods of Jupiter's satellites, Galileo proposed that with sufficiently accurate knowledge of their orbits one could use their positions as a universal clock, and this would make possible the determination of longitude. He worked on this problem from time to time during the remainder of his life; but the practical problems were severe. The method was first successfully applied by Giovanni Domenico Cassini in 1681 and was later used extensively for land surveys; for navigation, the first practical method was the chronometer of John Harrison. In his last year, when totally blind, he designed an escapement mechanism for a pendulum clock. The first fully operational pendulum clock was made by Christiaan Huygens in the 1650s. He created sketches of various inventions, such as a candle and mirror combination to reflect light throughout a building, an automatic tomato picker, a pocket comb that doubled as an eating utensil, and what appears to be a ballpoint pen. ballpoint pen

Church controversy

:Main article: Trial of Galileo. Not long after Galileo began publishing his astronomical work in The Starry Messenger, his Copernican ideas came under attack as a possible heresy, violating the Biblical picture of the Earth as the center of the universe (as well as the accepted philosophical teachings of the time). By 1616 the attacks seemed to Galileo to have become dangerous, and he went to Rome to try to persuade the Church authorities not to ban the new teachings. The mission was a failure: in the end, Cardinal Bellarmine, acting on orders from the Pope, delivered him an order not hold or defend the idea that the Earth moves and the Sun stands still at the center. For the next several years Galileo stayed well away from the controversy. Toward 1630, however, he revived his project of writing a book on the subject, encouraged by the election of Pope Urban VIII. The book, Dialogue Concerning the Two Chief World Systems, was published in 1632, with formal authorization from the Inquisition; there is dispute, however, concerning this license. Galileo was ordered to Rome to stand trial on suspicion of heresy in 1633. The sentence of the Inquisition was in three essential parts:
- Galileo was required to recant his heliocentric ideas, which were condemned as "formally heretical";.
- He was ordered imprisoned; the sentence was later commuted to house arrest.
- His offending Dialogue was banned; and in an action not announced at the trial, publication of any of his works was forbidden, including any he might write in the future. After a period with the friendly Archbishop Piccolomini in Siena, Galileo was allowed to return to his villa at Arcetri near Florence, where he spent the remainder of his life under house arrest.

Galileo's writings

Arcetri
- Two New Sciences 1638 Lowys Elzevir (Louis Elsevier) Leiden (in Italian, Discorsi e Dimostrazioni Matematiche, intorno á due nuoue scienze Leida, Appresso gli Elsevirii 1638)
- Dialogue Concerning the Two Chief World Systems 1632 (in Italian, Dialogo dei due massimi sistemi del mondo)
- The Starry Messenger 1610 Venice (in Latin, Sidereus Nuncius)
- Letter to Grand Duchess Christina

Writings on Galileo


- Galileo Galilei, an opera by Philip Glass
- Galileo a play by Bertolt Brecht

References


- Drake, Stillman (1953). Dialogue Concerning the Two Chief World Systems. Berkeley: University of California Press.
- Drake, Stillman (1957). Discoveries and Opinions of Galileo. New York: Doubleday & Company. ISBN 0-385-09239-3
- Drake, Stillman (1973). "Galileo's Discovery of the Law of Free Fall". Scientific American v. 228, #5, pp. 84-92.
- Drake, Stillman (1978). Galileo At Work. Chicago: University of Chicago Press. ISBN 0-226-16226-5
- Einstein, Albert (1952). Foreword to (Drake, 1953)
- Fantoli, Annibale (2003). Galileo — For Copernicanism and the Church, third English edition. Vatican Observatory Publications. ISBN 88-209-7427-4
- Fillmore, Charles (1931, 17th printing July 2004). Metaphysical Bible Dictionary. Unity Village, Missouri: Unity House. ISBN 0-871-59067-0
- Hellman, Hal (1988). Great Feuds in Science. Ten of the Liveliest Disputes Ever. New York: Wiley.
- Lessl, Thomas, "[http://www.catholiceducation.org/articles/apologetics/ap0138.html The Galileo Legend]". New Oxford Review, 27-33 (June 2000).
- Newall, Paula (2004). [http://www.galilean-library.org/hps.html "The Galileo Affair."]
- Settle, Thomas B. (1961). "An Experiment in the History of Science". Science, 133:19-23.
- Sobel, Dava. (1999). Galileo's Daughter. ISBN: 0-140-28055-3
- White, Andrew Dickson (1898). [http://www.santafe.edu/~shalizi/White/ A History of the Warfare of Science with Theology in Christendom]. New York 1898.

Named after Galileo


- The Galileo mission to Jupiter
- The Galilean moons of Jupiter
- Galileo Regio on Ganymede
- Galilaei crater on the Moon
- Galilaei crater on Mars
- Asteroid 697 Galilea (named on the occasion of the 300th anniversary of the discovery of the Galilean moons)
- Galileo (unit of acceleration)
- Galileo positioning system
- Galileo stadium in Miami, Florida

See also


- Galilean transformation
- Galilean invariance
- Lorentz transformation equations
- Medici
- Renaissance
- Vincenzo Galilei
- World Almanac's Ten Most Influential People of the Second Millennium

Notes


- Note 1: [http://www.lucidcafe.com/library/96feb/galileo.html Galileo, Lucid Cafe Feb '96]"

External links


- [http://www.newadvent.org/cathen/06342b.htm Galileo Galilei article at the Old Catholic Encyclopedia]
- [http://www.galilean-library.org/hps.html The Galileo Affair] by Paula Newall.
- [http://www.infidels.org/library/historical/andrew_white/Chapter3.html The Warfare of Science With Theology]
- [http://galileo.rice.edu/ The Galileo Project] at Rice University
- [http://www.pacifier.com/~tpope CCD Images through a Galilean Telescope] Modern recreation of what Galileo might have seen
- [http://wspace.danask.com/g/galileo_galilei.html about Galileo Galilei] at danask.com
- [http://www.mpiwg-berlin.mpg.de/Galileo_Prototype/MAIN.HTM Electronic representation of Galilei's notes on motion (MS. 72)]
- [http://www.firstthings.com/ftissues/ft0401/reviews/barr.html From Myth to History and Back] — Reviews of two books on Galileo
- [http://www.pbs.org/wgbh/nova/galileo/ PBS Nova Online: Galileo's Battle for the Heavens]
- [http://plato.stanford.edu/entries/galileo/ Stanford Encyclopedia of Philosophy entry]
- [http://www.galilean-library.org The Galilean Library], an educational site dedicated to Galileo
- [http://www.liberliber.it/biblioteca/g/galilei/ Galileo's writings in italian language], an italian site dedicated to free e-texts
- [http://www.newadvent.org/cathen/06342b.htm Galielo Galilei, in the Catholic Encyclopedia] found online on New Advent, an orthodox Catholic website Galilei Galilei Category:Astrologers Galilei Galilei Galilei Galilei Galilei als:Galileo Galilei ko:갈릴레오 갈릴레이 ja:ガリレオ・ガリレイ simple:Galileo Galilei th:กาลิเลโอ กาลิเลอี

Gan De

Gan De (c. 400 BC - c. 340 BC), also spelt Kan Te, was a Chinese astronomer reported to have seen one of the moons of Jupiter in about 362 BC. This was before Galileo's alleged discovery of the same in 1610. All four of the brightest moons are visible to the unaided eye, but often hidden by the glare of the main planet.

References


- X. Zezong,The Discovery of Jupiter's Satellite Made by Gan De 2000 years Before Galileo, Chinese Physics 2 (3) (1982), 664-667.
- "Sky and Telescope", February , 1981. Category:Chinese astronomers Category:400 BC births Category:340 BC deaths

362 BC

Centuries: 5th century BC - 4th century BC - 3rd century BC Decades: 410s BC 400s BC 390s BC 380s BC 370s BC 360s BC 350s BC 340s BC 330s BC 320s BC 310s BC 367 BC 366 BC 365 BC 364 BC 363 BC 362 BC 361 BC 360 BC 359 BC 358 BC 357 BC ----

Events


- Battle of Mantinea: The Thebans and their allies, under Epaminondas, defeat the Spartans and Athenians, but the brief period of Theban domination soon comes to an end.

Births


- Eumenes of Cardia

Deaths


- Epaminondas of Thebes Category:360s BC ko:362년

Voyager 1

The Voyager 1 spacecraft is an 815-kilogram unmanned probe of the outer solar system and beyond, launched September 5, 1977, and currently operational. It is the farthest human-made object from Earth. The Voyager 1 spacecraft has moved into the solar system's final frontier, a vast area where the Sun's influence gives way to interstellar space. At 14 billion kilometers (95 astronomical units or 8.8 billion miles) from the Sun, Voyager 1 has entered the heliosheath, a region beyond termination shock – the heliosheath is the shocked region between the solar system and interstellar space. If Voyager 1 is still functioning when it finally passes the heliopause, scientists will get their first direct measurements of the conditions in the interstellar medium. At this distance, signals from Voyager 1 take more than thirteen hours to reach its control center at the Jet Propulsion Laboratory, a joint project of NASA and Caltech near Pasadena, California. Voyager 1 is on a hyperbolic trajectory and has achieved escape velocity, meaning that its orbit will not return to the inner solar system. Along with Pioneer 10, the now deactivated Pioneer 11, and its sister ship Voyager 2, Voyager 1 is becoming an interstellar probe. Voyager 1 had as its primary targets the planets Jupiter and Saturn and their associated moons and rings; its current mission is the detection of the heliopause and particle measurements of solar wind and the interstellar medium. Both Voyager probes are powered by three radioisotope thermoelectric generators, which have far outlasted their originally intended lifespan, and are now expected to continue to generate enough power to keep communicating with Earth until around the year 2020.

Mission planning and launch

Voyager 1 was originally planned as Mariner 11 of the Mariner program. From the outset, it was designed to take advantage of the then-new technique of gravity assist. By fortunate chance, the development of interplanetary probes coincided with an alignment of the planets called the Grand Tour. The Grand Tour was a linked series of gravity assists that, with only the minimal fuel needed for course corrections, would enable a single probe to visit all four of the solar system's gas giant planets: Jupiter, Saturn, Uranus and Neptune. The identical Voyager 1 and Voyager 2 probes were designed with the Grand Tour in mind, and their launches were timed to enable the Grand Tour if desired. Voyager 1 was launched on September 5, 1977 by NASA from Cape Canaveral aboard a Titan IIIE Centaur rocket, slightly after its sister craft, Voyager 2. Despite being launched after Voyager 2, Voyager 1 was sent on a faster trajectory so it reached Jupiter and Saturn before its sister craft. Initially, an underburn in the second stage of the Titan IIIE rocket left an estimated one second worth of fuel remaining in that stage. Although ground crews were worried that Voyager 1 would not make it to Jupiter, the Centaur upper stage proved to have enough fuel to compensate. For details on the Voyager instrument packages, see the separate article on the Voyager program.

Jupiter

Voyager program Voyager 1 began photographing Jupiter in January 1979. Its closest approach to Jupiter was on March 5, 1979, at a distance of 349,000 kilometers (217,000 miles) from its center. Due to the greater resolution allowed by close approach, most observations of the moons, rings, magnetic fields, and radiation environment of the Jupiter system were made in the 48-hour period bracketing closest approach. It finished photographing the planet in April. The two Voyager spacecraft made a number of important discoveries about Jupiter and its satellites. The most surprising was the existence of volcanic activity on Io, which had not been observed from the ground or by Pioneer 10 or 11.

Saturn

11 The gravity assist at Jupiter was successful, and the spacecraft went on to visit Saturn. Voyager 1s Saturn flyby occurred in November 1980, with the closest approach on November 12 when it came within 124,000 kilometers (77,000 miles) of the planet's cloud-tops. The craft detected complex structures in Saturn's rings, and studied the atmospheres of Saturn and Titan. Because of the earlier discovery of a thick atmosphere on Titan, the Voyager controllers at the Jet Propulsion Laboratory elected for Voyager 1 to make a close approach of Titan and terminate its Grand Tour. (For the continuation of the Grand Tour, see the Uranus and Neptune sections of the Voyager 2 article.) The Titan-approach trajectory caused an additional gravity assist that took Voyager 1 out of the plane of the ecliptic, thus ending its planetary science mission.

Interstellar mission

It is estimated both Voyager craft would have sufficient electrical power to operate at least some instruments until 2020.

Heliopause

2020] As the Voyager 1 space probe heads for interstellar space, its instruments continue to study the solar system; Jet Propulsion Laboratory scientists are using the plasma wave experiments aboard Voyager 1 and 2 to look for the heliopause. Scientists at the Johns Hopkins University Applied Physics Lab believe that Voyager entered the termination shock in February 2003. Some other scientists have expressed doubt, discussed in the journal Nature of November 6 2003. In a scientific session at the American Geophysical Union meeting in New Orleans on the morning of March 25 2005, Dr. Ed Stone presented clear evidence that Voyager 1 crossed the termination shock in December 2004 [http://www.agu.org/cgi-bin/SFgate/SFgate?&directget=1&application=sm05&database=%2Fdata%2Fepubs%2Fwais%2Findexes%2Fsm05%2Fsm05&=%22SH22A-01%22]. The issue will not be resolved for some months as other data become available, since Voyagers solar-wind detector ceased functioning in 1990. However, in May 2005 a NASA press release said that consensus was that Voyager 1 was now in the heliosheath. [http://www.nasa.gov/vision/universe/solarsystem/voyager_agu.html].

Distance travelled

In March 2005, Voyager 1 was at a distance of 14.2 billion kilometers (95.0 AU or 8.83 billion miles) from the Sun, which makes it the most distant man-made object from Earth. It was travelling at a speed of 17.2 kilometers per second (3.6 AU per year or 38,400 miles per hour), 10% faster than Voyager 2. It is not heading straight towards any particular star, but even if Voyager 1 were going straight toward the closest star system, Alpha Centauri, it would take about 80,000 years to get there.

See also


- Voyager program
- Voyager Golden Record

External links


- [http://voyager.jpl.nasa.gov NASA Voyager website]
- [http://voyager.jpl.nasa.gov/spacecraft/spacecraftlife.html Voyager Spacecraft Lifetime] - Interstellar mission coverage.
- [http://www.heavens-above.com/solar-escape.asp Spacecraft Escaping the Solar System] - current positions and diagrams
- [http://www.cnn.com/2005/TECH/space/05/25/voyager.space/index.html CNN: NASA: Voyager I enters solar system's final frontier] - May 25, 2005
- [http://voyager.jpl.nasa.gov/mission/weekly-reports/ Weekly Mission Reports] - includes information on current spacecraft state Category:Jupiter spacecraft Category:Voyager program Category:Saturn spacecraft ko:보이저 1호

1979

This page refers to the year 1979. For the Smashing Pumpkins song, see 1979 (song). 1979 (MCMLXXIX) is a common year starting on Monday.

Events


- 1979 energy crisis - occurred in the wake of the Iranian Revolution

January


- January 1 - United Nations Secretary-General Kurt Waldheim heralds the start of the "International Year of the Child." Many musicians donate to the "Music for UNICEF" fund.
- January 1 - Sino-American relations: United States and the People's Republic of China establish diplomatic relations
- January 4 - State of Ohio agrees to pay $675,000 to families of dead and injured in Kent State University shootings.
- January 7 - Vietnam and Vietnam-backed Cambodian insurgents announce the fall of Phnom Penh, Cambodian capital, and the collapse of the Pol Pot regime. Pol Pot and Khmer Rouge retreat to Thailand
- January 8 - The French tanker Betelgeuse explodes at the Gulf Oil terminal at Bantry in Ireland - 50 dead
- January 13 - YMCA sues the Village People for libel because of their song of the same name
- January 16 - The Shah of Iran flees Iran with his family and relocate to Egypt after a year of turmoil.
- January 19 - Former US Attorney General John N. Mitchell released on parole after 19 months at a federal prison in Alabama
- January 29 - Brenda Ann Spencer opens fire at random in San Diego, California, killing two teachers and wounding 8 students

February


- February 1 - Convicted bank robber Patty Hearst is released from prison after her sentence was commuted by President Jimmy Carter
- February 1 - Ayatollah Ruhollah Khomeini returns to Tehran, Iran after nearly 15 years of exile.
- February 2 - Sid Vicious dies of heroin overdose
- February 3 - Khomeini creates the Council of the Islamic Revolution
- February 7 - Supporters of Khomeini take over the Iranian law enforcement, courts and government administration
- February 7 - Pluto moves inside Neptune's orbit for the first time since either planet was known to science.
- February 10-February 11 - Iranian army mutinies and joins the Islamic Revolution
- February 11 - Khomeini seizes power in Iran.
- February 14 - In Kabul, Muslim extremists kidnap the American ambassador to Afghanistan, Adolph Dubs, who is later killed during a gunfight between his kidnappers and police
- February 14 - Musician Walter Carlos reveals that he has undergone a sex change operation and become Wendy
- February 17 - The People's Republic of China invades northern Vietnam, launching the Sino-Vietnamese War.
- February 22 - Independence of Saint Lucia from the United Kingdom.

March

March and Prime Minister Menachem Begin of Israel sign the Camp David Accords.]]
- March 1 - Scotland voted narrowly for home rule, which was not implemented, and Wales voted against
- March 5 - Voyager I passes Jupiter
- March 13 - In Grenada, Maurice Bishop leads a successful coup
- March 14 - In China, a Hawker-Siddeley Trident crashes into a factory near Beijing killing at least 200
- March 25 - The first fully functional space shuttle orbiter, Columbia, was delivered to the John F. Kennedy Space Center to be prepared for its first launch
- March 26 - In a ceremony at the White House, President Anwar Sadat of Egypt and Prime Minister Menachem Begin of Israel sign a peace treaty
- March 28 - Nuclear power plant accident at Three Mile Island, Pennsylvania, releases radiation
- March 28 - In Britain, Jim Callaghan's government loses a motion of confidence by one vote, forcing a general election
- March 29 - Sultan Yahya Petra ibni Almarhum Sultan Ibrahim Petra, 6th Yang di-Pertuan Agong of Malaysia dies in office. He is replaced by Sultan Haji Ahmad Shah Al-Mustain Billah ibni Almarhum Sultan Sir Abu Bakar Riayatuddin Al-Muadzam Shah, Sultan of Pahang.
- March 30 - Airey Neave, World War Two veteran and Conservative Northern Ireland spokesman, is killed by INLA bomb in British House of Commons car park
- March 31 - The Royal Navy withdraws from Malta

April-May

May.]]
- April 1 - Iran's government becomes Islamic Republic by a 98% vote, overthrowing the Shah officially
- April 1-April 18 - Police lock Andreas Mihavecz in a holding cell in Bregenz, Austria and forget him there for the next 18 days without food or drink
- April 2 - Soviet biowarfare laboratory at Sverdlovsk accidentally releases airborne anthrax spores. 66 dead plus unknown amount of livestock
- April 4 - President Zulfikar Ali Bhutto of Pakistan is executed
- April 10 - A tornado hits in Wichita Falls, Texas killing 42 people. It was the most notable tornado of twenty-six that hit that day.
- April 11 - Tanzanian troops take Kampala, the capital of Uganda. Idi Amin flees
- April 17 - Schoolchildren in the Central African Republic arrested for protesting against wearing the expensive, school uniforms. Around 100 killed.
- April 23 - Fighting in London between the Anti-Nazi League and the Metropolitan Police's Special Patrol Group results in the death of protestor Blair Peach
- May 1 - Greenland gets home rule
- May 4 - Conservatives win the British general election; Margaret Thatcher becomes the new prime minister.
- May 9 - Unabomber bomb injures Northwestern University graduate student John Harris
- May 10 - The Federated States of Micronesia becomes self-governing.
- May 25 - American Airlines Flight 191: In Chicago, Illinois, a DC-10 crashes during takeoff at O'Hare International Airport killing 271 on board and two people on the ground.

June


- June 1 - The first black-led government of Rhodesia in 90 years takes power, in succession to Ian Smith and under his power-sharing deal.
- June 2 - Pope John Paul II visits his native Poland, becoming the first Pope to visit a Communist country
- June 3 - A blowout at the Ixtoc I oil well in the southern Gulf of Mexico causes at least 600,000 tons (176,400,000 gallons) of oil to be spilled into the waters, the worst oil spill to date. Some estimate the spill to be 428 million gallons, making it the largest unintentional oil spill ever.
- June 4 - Joe Clark becomes Canada's sixteenth, and youngest, prime minister.
- June 12 - Bryan Allen flies the Gossamer Albatross, man powered, across the English Channel.
- June 18 - J