Eighth planet discovered - Sep 23, 1846 - HISTORY.com Eighth planet discovered A+E Networks German astronomer Johann Gottfried Galle discovers the planet Neptune at the Berlin Observatory. Neptune, generally the eighth planet from the sun, was postulated by the French astronomer Urbain-Jean-Joseph Le Verrier, who calculated the approximate location of the planet by studying gravity-induced disturbances in the motions of Uranus. On September 23, 1846, Le Verrier informed Galle of his findings, and the same night Galle and his assistant Heinrich Louis d’Arrest identified Neptune at their observatory in Berlin. Noting its movement relative to background stars over 24 hours confirmed that it was a planet. The blue gas giant, which has a diameter four times that of Earth, was named for the Roman god of the sea. It has eight known moons, of which Triton is the largest, and a ring system containing three bright and two dim rings. It completes an orbit of the sun once every 165 years. In 1989, the U.S. planetary spacecraft Voyager 2 was the first human spacecraft to visit Neptune.

Related Videos Johann Gottfried Galle | German astronomer | Britannica.com Johann Gottfried Galle Friedrich Wilhelm Bessel Johann Gottfried Galle, (born June 9, 1812, near Gräfenhainichen, Prussian Saxony—died July 10, 1910, Potsdam , Ger.), German astronomer who on Sept. 23, 1846, was the first to observe the planet Neptune . Galle joined the staff of the Berlin Observatory, where he served as assistant director under J.F. Encke from 1835 until 1851. He studied the rings of Saturn and suggested a method, later successful, of measuring the scale of the solar system by observing the parallax of asteroids. He looked for Neptune at the request of the French astronomer U.-J.-J. Le Verrier, who had computed the planet’s probable position before it was seen. From 1851 until 1897 Galle was director of the Breslau Observatory. Learn More in these related articles: Neptune (planet) third most massive planet of the solar system and the eighth and outermost planet from the Sun.

Because of its great distance from Earth, it cannot be seen with the unaided eye. With a small telescope, it appears as a tiny, faint blue-green disk. It is designated by the symbol ♆. in astronomy: Precise calculations and observations ...zodiac where astronomers should look, but at first he could not get the English astronomical community to tackle the job. Leverrier had better luck, for his prediction was taken up immediately by Johann Gottfried Galle at the Berlin Observatory, who found the new planet Neptune in 1846, near the place in the sky where Leverrier said it would be. This episode caused a stormy period in... in Neptune (planet): Neptune’s discovery ...in his country that a telescopic search of the skies in the area he predicted for the new planet was not a waste of time. On September 23, 1846, he communicated his results to the German astronomer Johann Gottfried Galle at the Berlin Observatory. Galle and his assistant Heinrich Louis d’Arrest had access to detailed star maps of the sky painstakingly constructed to aid in the search for new... More about Johann Gottfried Galle 3 References found in Britannica Articles Assorted References Corrections?

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Please note that our editors may make some formatting changes or correct spelling or grammatical errors, and may also contact you if any clarifications are needed. Uh Oh There was a problem with your submission. Please try again later. Close Article Title: Johann Gottfried Galle Website Name: Encyclopædia Britannica Date Published: July 20, 1998 URL: Access Date: January 20, 2017 Share Neptune - Astronomy For Kids - KidsAstronomy.com ASTRONOMY FOR KIDS Try Miamiopia, Our New Free Educational Virtual World Neptune means: At first, Neptune was only the god of water, but later on this was extended to include the sea when he became associated with the Greek god Poseidon. How much would you weigh on Neptune? If you weigh 70 pounds (32 kg) on the Earth, you would weigh 78.5 pounds (36 kg) on Neptune. The Planet For many, centuries people did not know that this planet even existed. It was discovered by Johann Galle and Heinrich D'Arrest in 1846. Neptune is the smallest of the four gas giants in our Solar System.

Much like Saturn and Uranus, Neptune's atmosphere contains hydrogen, helium and methane. Not much was known about Neptune until it was visited by the spacecraft Voyager 2 on August 25, 1989. Voyager 2 took many pictures of the planet, and much of what we know today about Neptune came from this single visit. These pictures show a brilliant blue planet with a few thin white clouds laced around its surface. In Neptune's atmosphere, there is a large white cloud that moves around rather quickly. The "scooting" of this cloud around the atmosphere has led it to be named "Scooter." When Voyager 2 visited Neptune, its pictures showed a giant storm much like the storm on Jupiter. This storm is called the "Great Dark Spot" because it appears as a dark oval shape on the surface of the planet. We do not know how long this storm has been active or if it is still present. More recently, the Hubble Space Telescope sent pictures back to Earth and there was no sign of the Great Dark Spot. These pictures did show two other dark spots that eventually faded away. Neptune is a very windy place. No other planet in the Solar System has winds that are as strong as Neptune's.

The winds near the Great Dark Spot were believed to have reached nearly 1,200 miles per hour (approx 1931 km per hour). Perhaps this extremely windy atmosphere contributes to the appearance and disappearance of the great dark spots. Rings Neptune has six rings which circle the planet. These rings are believed to be fairly new. The rings are more irregular than the rings of other planets. There are areas of varying thickness throughout the rings. Moons: Neptune has 13 moons that we know of. Because Neptune is so far away, it is difficult to see any of these worlds. There are probably many more moons orbiting this blue planet which we have not yet discovered. Perhaps you will be the astronomer who discovers some of these worlds. The first moon to be discovered was Triton. Triton was discovered by an amateur astronomer in England named William Lassell only 17 days after Neptune was discovered in 1846. The names of the other moons are: Despina, Galatea, Halimede, Laomedeia, Larissa, Naiad, Nereid, Neso, Proteus, Psamathe, Sao, and Thalassa.

To learn more about these worlds, Click Here . Neptune's circular orbit is offset from the Sun. At times, Neptune's orbit takes it further from the Sun than any other planet in the Solar System. In 2011, Neptune will complete its first orbit around the Sun since it was discovered in 1846. The Totally Free Children's Learning Network Educational Games When were each of the planets first discovered and who did it? When were each of the planets first discovered and who did it? Answer: Only 3 of the 9 planets in our solar system have official "discoverers" and "times of discovery". The reason is simple - all of the other planets are easily seen by the unaided human eye. This means that humankind has been looking at these objects (whether they understood what they were or not) since first gazing at the night sky! Three planets required good telescopes for their discovery: Uranus was discovered by Sir William Herschel in 1781. Herschel was probably the most famous astronomer of the 18th century.

In addition to discovering the planet Uranus, he also observed and cataloged over 800 double stars and 2,500 nebulae. He was the first astronomer to correctly describe the spiral structure of our Milky Way Galaxy . Neptune was discovered by John Couch Adams in 1846. Adams was an English astronomer and mathematician who, at the age of 24, was the first person to predict the position of a planetary mass beyond Uranus. Adams did not publish his prediction and it is a miracle that he is given credit by the scientific community for his work (let this be a lesson!). German astronomer Johann Gottfried Galle (along with Heinrich Louis d'Arrest) confirmed the existance of Neptune based on independent, published, calculations done by French mathematician Urbain Jean Joseph Le Verrier. Sometimes you will see Couch and Le Verrier cited together as the "discoverers of Neptune". Pluto was discovered by astronomer Clyde Tombaugh in 1930. A 9th planet had been looked for for some time. It was believed that such a planet had to exist in order to explain some odd things happening in the orbits of Uranus and Neptune.

Tombaugh did a careful sky survey at the Lowell Observatory in Arizona. As a result, he discovered Pluto. The interesting thing to know is that all of the orbital problems with Uranus and Neptune vanish when the correct mass of Neptune is used in the equations; the correct mass was determined by the Voyager 2 spacecraft when it flew by that planet in 1989. So Tombaugh got lucky - he found a planet where a flawed prediction said one would be! Who discovered each planet? (Intermediate) - Curious About Astronomy? Ask an Astronomer Who discovered each planet? (Intermediate) Who discovered each planet in the solar system, and when did they discover it? Some of the planets have been known to people for as long as they have been watching the stars. Mercury, Venus, Mars, Jupiter and Saturn can all be seen with the naked eye, so it's impossible to say who was the first human to discover them, and when that was! Uranus was discovered by William Hershel on March 13, 1781. He was searching the sky with his telescope, and realized that Uranus was moving with respect to the stars.

Other people had seen Uranus before--even marked it on their star charts--but they didn't realize that it wasn't a star. Based on small perturbtions in the orbit of Uranus, John Adams and Urbain Le Verrier predicted the position of another, more distant planet. Though John Adam's prediction was first, by about a month, the observers Johann Galle and Heinrich Louis d'Arrest used LaVerrier's position, and were the first people to observe the planet Neptune--and know what they were looking at--on September 18, 1846. Again, many people had seen Neptune before, including, surprisingly, Galileo Galilei, who noted a "star" in the field during his observations of Jupiter, which we now believe was actually Neptune. Pluto (now a dwarf planet), was discovered by Clyde Tombaugh on February 18, 1930. He found it in a location predicted by apparent perturbations in the orbit of Neptune.

However, we now know that Pluto is too small to cause a measureable change in Neptune's orbit, and that the "perturbations" were actually just errors in the measurement of the positions of the planets, so Tombaugh was just lucky. Here is an excellent article about how mathematics and the laws of physics were used in the discovery of the outer planets . Johann Gottfried Galle | Pleasant's Personal Blog! Leave a reply Image of Neptune showing the Great Dark Spot – Courtesy NASA Neptune turned “one year” old yesterday when it completed its first revolution around the sun since its discovery 165 years ago. Astronomy world celebrated this event as Neptune completed its one year which is 164.79 earth years yesterday. Named after the Roman Sea God, the 8th and last planet of our Solar System, Neptune’s location was mathematically predicted and discovered by Urbain Le Verrier, John Couch Adams and Johann Gottfried Galle putting an end to decades old question “Who was tugging on Uranus?” Galileo observed Neptune on December 28, 1612 and again on January 27, 1613 and recorded the findings in his drawings.

However, he is not credited with the discovery of the planet since he mistook Neptune as a distant star that appeared in conjunction with Jupiter. Neptune had turned retrograde on the day when Galileo discovered it, however, according to physicist David Jamieson, Galileo was at least aware that the “star” he discovered moved relative to the fixed starts. Substantial deviations from astronomical tables of Uranus’s orbit published in 1821 by French astronomer Alexis Bouvard was subsequently observed leading him to hypothesise that an unknown body was perturbing the orbit of Uranus through gravitational interaction. British astronomer John Couch Adams in 1843, began work on Uranus’s orbit using the data sent to him by the then Astronomer Royal Sir George Airy through James Challis, the then Cambridge Observatory director. His mathematical work through 1845-46 produced several estimates of the existence a new planet. Neptune’s Orbit compared to other planet – Courtesy Wikipedia During the same period, French astronomer Urbain Le Verrier independently developed his own calculations about the new planet but did not stimulate enthusiasm in his fellow astronomers.

In June 1846, Sir George Airy, upon seeing the similarity of Le Verrier’s first published estimate of the planet’s longitude to that of Adams’s estimate, Airy persuaded James Challis to search for the planet though the search that lasted throughout August and September of that year did not produce any results. Meanwhile, a letter was sent to the German astronomer Johann Gottfried Galle of Berlin Observatory by Le Verrier requesting him to search for the new planet using the observatory’s refractor. A student at the observatory, Heinrich d’Arrest suggested to Galle that they might be able to make the discovery if they compared the chart drawn about the region predicted by Le Verrier and with the current sky to seek the displacement characteristic of the planet as opposed to a fixed star. It worked and that very evening on September 23, 1846, Neptune was discovered within 1° of where Le Verrier had predicted and about 12° from Adams’ prediction. James Challis later realised that he did observe the planet twice in August but failed to identify it due to his casual approach to the work.

There have been much debate between France and Great Britain as to who should get the credit of the discovery of the planet. However, it was decided through international consensus that both Adams and Le Verrier should be credited equally even though to this day there are people who do not credit Adams with the discovery. Neptune shot by Hubble at four time intervals – Courtesy NASA Neptune is 2.8 billion miles from the Sun which is about 30 times farther than Earth making it slow and freezing cold. The image shows the planet in four hour intervals within Neptune’s 16-hour day. The white fluffy streaks are clouds, but not of the Earth variety. Due to the low ambient temperature of the planet, they are high-altitude swaths of frozen methane. Neptune has a 29-degree tilt, which, like Earth’s tilt of 23-degrees, causes the planet to experience seasons. Currently Neptune is experiencing summer in the southern hemisphere and winter in the north. While a season lasts only a few months on Earth, it lasts up to 40 years on Neptune. Planetary scientist Dr. Craig O’Neil of Macquarie University says that we still haven’t learned much about Neptune since its discovery.

“It’s location at the edge of the solar system makes it a bit of a black hole from a knowledge point of view,” he says. According to him, the huge distance from the sun makes sun look like a point of light in Neptune no brighter than Venus does from Earth. Most of what we know about Neptune today comes from Voyager 2’s fly-by of the planet in 1989 and the Hubble Space Telescope. Neptune’s Rings shot by Voyager 2 in 1989 – Courtesy Wikipedia Neptune does have a planetary ring system, though it is less substantial than that of Saturn. The rings may consist of ice particles coated with silicates or carbon-based material giving them a reddish hue. The three main rings are the narrow Adams Ring, 63000 km from the centre of Neptune, the Le Verrier Ring, at 53000 km, and the broader, fainter Galle Ring, at 42000 km. A faint outward extension to the Le Verrier Ring has been named Lassell; it is bounded at its outer edge by the Arago Ring at 57000 km. Observations show that the rings are more unstable than previously thought.

Images taken from the W. M. Keck Observatory in 2002 and 2003 show considerable decay in the rings compared to images by Voyager 2. Most of the atmosphere of Neptune is made of hydrogen, helium and methane. The blue colour supposedly comes from methane absorbing red light. However, Uranus, that has a similar atmosphere is cyan in colour. Scientists are still speculating about the supersonic winds of Neptune which are the fastest in the Solar System since their speed of 2,000 kilometres per hour do not conform to the large distance from the sun. “The Sun can’t be powering what’s happening there. Given Uranus has fairly mild winds, Neptune’s dynamics are a mystery. One idea is that if you put methane under enough pressure deep in Neptune’s atmosphere, it could convert to diamond which would fall as rain. This conversion process releases heat which could power the winds. That’s a little more speculative, but speculation is all we’ve got, ” says Dr. O’Neil. Neptune’s Moons by Hubble – Courtesy NASA Shown above is a composite image of Hubble shots stitched together by NASA. You can see multiple moons within the same orbit due to the time lapse between shots.

In order to get the true hue of Neptune’s atmosphere, NASA took numerous photos with three different colour filters. Over 30 moons have been discovered orbiting Neptune but the majority orbit farther away to fit into this shot. Gravit Theme powered by WordPress The Solar System: Neptune | The Institute for Creation Research The Solar System: Neptune Resources › Physical Sciences Resources › Astronomy The year was 1989. A small, unmanned space probe rapidly approached the mysterious and unexplored planet Neptune. Launched in 1977, the Voyager 2 spacecraft had already visited Jupiter, Saturn, and Uranus, imaging each of these beautiful worlds in unprecedented detail. A rare alignment of the outer four planets made this Planetary Grand Tour possible as NASA scientists were able to use the gravity of each planet to “slingshot” the craft outward to the next world.1 Voyager 2 had traveled over four billion miles during its 12-year mission and was about to become the only spacecraft to visit distant Neptune. This encounter would mark the end of an era of planetary space exploration since Neptune was the one remaining planet unvisited by space probes.2 Astronomers all over the world waited eagerly for the first high-resolution images. What wonderful secrets would be revealed?

A Triumph of Newtonian Physics Neptune is the only planet in our solar system that was known to exist before it was visually discovered. The counterintuitive story begins with the creation scientist Sir Isaac Newton, who formulated the laws of motion and gravity in the latter half of the 17th century. Newton mathematically demonstrated that the motion of planets could be explained by the sun’s force of gravity deflecting their momentum into an elliptical path. This accounted for Kepler’s laws.3 But it also allowed astronomers to refine their calculations of planetary orbits to include the gravitational influence of other planets—something Kepler’s laws simply could not do. The new physics worked perfectly, correctly predicting the precise position for every planet…except Uranus. By 1845, the planet Uranus had traversed three quarters of its orbit around the sun since its discovery in 1781, so its path was well known. Its orbital motion nearly matched the mathematical predictions from Newton’s laws. But it was not a perfect fit even when the gravitational perturbations of the other known planets were included. What was going on? Were Newton’s laws incorrect at such extreme distance? Or was there another planet—an unknown planet—pulling on Uranus?

Urbain Le Verrier, a French mathematician, began considering the latter possibility. After many months of intense calculations, he mathematically computed the position that the unknown planet must have in order to explain the discrepancies in the orbit of Uranus. Le Verrier mailed his findings to Johann Galle of the Berlin Observatory. Galle received the letter on September 23, 1846, and, with the help of Heinrich d’Arrest, visually located Neptune that very evening. The new planet was within one degree of the position predicted by Le Verrier. This remarkable achievement led physicist Francois Arago to refer to Le Verrier as the man who “discovered a planet with the point of his pen.”4 Some people suggested naming this new world “Le Verrier’s planet.” But, William Herschel’s failed attempt to name Uranus after King George III had established that planets may not be named after people—at least not directly. Le Verrier insisted that he had the right to name the new planet. Following traditional nomenclature, he christened the new world “Neptune” after the Roman god of the sea.

The name fits the sea-blue color of the planet and indirectly pays homage to Isaac Newton by sharing the first two letters of his name. Properties At an average solar distance of 2.8 billion miles (over 30 times farther out than Earth), Neptune is the most distant planet of the solar system.5 This makes it a difficult world to study. It is too faint to be seen with the unaided eye under any circumstances but can be detected in binoculars and is easily visible in a backyard telescope. In fact, it is likely that Galileo saw Neptune hundreds of years before its official discovery. This was purely by accident during one of his routine observations of Jupiter. On January 4, 1613, Jupiter passed directly in front of Neptune for several hours.6 While Galileo’s telescope was meager by today’s standards, Neptune would certainly have been visible for many nights before and after this event, though it would have been indistinguishable from background stars. Today, Neptune appears as a tiny, solid-blue sphere in even the most powerful Earth-based telescopes. Atmospheric features, such as white clouds, are occasionally visible—but just barely. Neptune takes 164.8 years to orbit the sun.

It has completed only one orbit since its discovery and only 36 orbits since its creation. Physically, Neptune is a virtual twin of Uranus. Both worlds are four Earth-diameters in size and have similar compositions: an icy core surrounded by a thick atmosphere of hydrogen, helium, and small amounts of methane. The methane causes the blue color of both planets. Neptune’s largest moon is named Triton.7 English astronomer William Lassell discovered this moon only 17 days after the discovery of Neptune itself. Triton is 23 percent smaller in diameter than Earth’s moon, making it the seventh-largest moon in the solar system. In contrast to all other large moons, Triton’s orbit is retrograde—opposite the direction that the planet spins. Large moons generally orbit in the plane of their planet’s equator, but Triton breaks this rule as well and orbits at an angle of 23 degrees.8 It is only because Triton is so large that it could be easily discovered at such a distance with 19th-century telescopes. All of Neptune’s other moons are much smaller and evaded detection for over a century.

Nereid, a small moon—just over 100 miles in diameter—with a highly eccentric (elliptical) orbit, was discovered in 1949.9,10 It comes within 853,000 miles of Neptune but then swings out to a distance of nearly six million miles. A third moon, Larissa, wasn’t detected until 1981. The rest remained hidden until the Voyager 2 encounter. The Science of Voyager 2 Our understanding of Neptune took a leap forward when Voyager 2 arrived. One of the first discoveries was the detection of a system of rings. The existence of Neptune’s rings had been suspected based on previous research, but Voyager 2 was the first to directly image them. At first, the rings appeared as arcs, only partially encircling the planet. But as Voyager 2 drew closer, the rings were found to be complete, though thicker in certain places, which accounted for the arcs. Neptune has five major rings. They seem to be a mosaic of the types of rings encircling the other Jovian (gas giant) planets.

Three of them are thin threads, like the rings of Uranus; the two others are broad sheets, like Saturn’s rings, but are thin like Jupiter’s. The rings are named for people who were involved in some way with the planet’s discovery: Galle, Le Verrier, Lassell, Arago, and Adams. Voyager 2 also discovered five new moons orbiting close to Neptune. They are all small, less than 300 miles in diameter, with circular, prograde orbits in the plane of Neptune’s equator.11 With technological breakthroughs in ground-based imaging, several additional moons were discovered in the years following the Voyager 2 encounter. These bring the total known moons of Neptune to 14. Another fantastic surprise revealed by Voyager 2 was the discovery of a large dark spot in Neptune’s southern hemisphere. It is an anticyclone comparable in size to the earth and qualitatively similar to Jupiter’s Great Red Spot. But, whereas Jupiter’s red spot is relatively permanent, Neptune’s dark spot was short-lived. In 1994, the Hubble Space Telescope revealed that the spot had disappeared and, surprisingly, a new dark spot had formed in Neptune’s northern hemisphere.

It, too, was short-lived and has long since disappeared. Voyager 2 also examined the surface of Triton in superb detail. The images revealed another scientific discovery—numerous horizontal, dark streaks in Triton’s southern hemisphere. These were found to be “geysers” of nitrogen gas caused by solar heating of the frozen surface. Though the gas is transparent, the geysers pick up dark surface dust and launch it into Triton’s tenuous nitrogen atmosphere. Eastward winds carry the dust many miles, accounting for the dark, horizontal streaks. Confirmation of Creation Unlike Uranus, Neptune has considerable internal heat, radiating more than twice the energy it receives from the sun. It is hard to imagine how such a process could last for billions of years, but is not a problem for the biblical timescale. In addition, it is curious that Uranus lacks any internal heat, despite being nearly identical to Neptune in every other way. How can an evolutionary scenario make sense of this? Yet, this similarity-with-differences is a common characteristic that the Lord built into the universe. Diversity with unity is part of what makes science possible and is what we expect from the triune God.

Voyager 2 also measured the magnetic field of Neptune and found it to be similar in strength to that of Uranus. This is consistent with Neptune’s biblical age of about 6,000 years but is far stronger than what we would expect if the planet were billions of years old since magnetic fields decay with time.12 As with its twin Uranus, Neptune’s magnetic field is not even remotely aligned with the rotation axis and does not pass through the center of the planet. Such facts are consistent with the creative diversity of our Lord but are difficult to account for in secular dynamo models.13 Conclusion The most distant planet of our solar system remained hidden from humanity for nearly 6,000 years. Only with the recent advances in technology have scientists been able to learn some of the secrets of Neptune. Most of these discoveries were made possible by the Voyager 2 mission—the only spacecraft to visit this fascinating world.14 As with the other planets, Neptune gives us a glimpse of the glory of the Lord.15 References Such an alignment occurs approximately once every 175 years. At the time, Pluto was classified as a planet.

However, the trajectories of Voyager 1 and 2 were not suitable for a Pluto flyby. Since Pluto was reclassified as a dwarf planet in 2006, Neptune was the last of the eight planets to be explored. The New Horizons spacecraft is scheduled to fly by Pluto in July 2015. Johannes Kepler had previously shown (1) that planets orbit in ellipses with the sun at one focus, (2) that planets sweep equal areas in equal times, and (3) that the period squared of a planet is proportional to the cube of its average distance from the sun. But Kepler had no idea why planets followed such rules. Newton was able to show that these rules can be mathematically derived from the laws of motion and the force of gravity from the sun. Essentially, Newton’s laws are the reason why Kepler’s laws work. Though Le Verrier is credited with the discovery of Neptune, John Couch Adams had independently computed its position around the same time as Le Verrier. Many astronomy books credit Adams as a co-discoverer. But it was Le Verrier who first published his results and whose discovery led to the visual detection of Neptune.

Johann Galle is rarely credited, even though he and Heinrich d’Arrest were the first to actually see Neptune and recognize it as a planet. Neptune was the most distant planet of the solar system during the Voyager 2 flyby in 1989. It is also the most distant planet today but for a different reason. Most schoolchildren in the 20th century learned that Pluto was the most distant planet. However, the elliptical orbit of Pluto occasionally overlaps that of Neptune such that Pluto is closer to the sun than Neptune for certain periods of time. This was the case between 1979 and 1999. Today, Pluto is more distant than Neptune but has not been considered a planet since its reclassification in 2006. An occultation (occult, as a verb, means “to cover”) is when a larger celestial object passes directly in front of a smaller one. Conversely, when a smaller object passes in front of a larger one, the event is called a transit. The moon often occults bright stars and sometimes planets. But mutual planetary occultations and transits are extremely rare.

Jupiter would occult Neptune again in 1702, but no further occultations of these two planets have taken place since and will not happen again until the year 3428! Triton should not be confused with Titan, Saturn’s largest moon. The only other large satellite that does not orbit in its planet’s equator is Earth’s moon. It deviates from the equator by 23.4 degrees on average—about the same amount as Triton. Eccentricity is a measure of how elliptical an orbit is. An orbiting object can have an eccentricity as low as zero (denoting a perfectly circular orbit) or up to, but not including, one. An eccentricity of one or higher means the object is travelling at or faster than escape velocity and will never return to complete an orbit. Nereid has an orbital eccentricity of 0.75—the second-highest of known moons. Only Saturn’s moon Bestla has a higher eccentricity at 0.77. The term prograde means that the moons orbit in the same direction that the planet rotates.

See my article on Uranus in the February 2014 issue of Acts & Facts for more information on magnetic fields as an indication of the youth of the solar system. Dynamo models were invented as a way to continuously recharge planetary magnetic fields so that they can allegedly last for billions of years. These models have been so far unsuccessful, not only on the theoretical level but in terms of observations as well. Voyager 2 has since left the solar system and is now three times farther from the sun than Neptune. Its radioisotope battery is nearly depleted, but the craft will continue to coast silently through the void. Psalm 19:1. Image credit: NASA * Dr. Lisle is Director of Physical Sciences at the Institute for Creation Research and received his Ph.D. in astrophysics from the University of Colorado. Cite this article: Jason Lisle, Ph.D. 2014. The Solar System: Neptune . Acts & Facts. 43 (3). The Solar System Try Miamiopia, Our New Free Educational Virtual World In order to streamline this page for printing, many graphics have been removed. Mercury Mercury means: Mercury was the Roman version of the god Hermes.

He was the messenger for the other gods, and for this reason Mercury is often depicted in pictures with winged sandals. In addition to delivering messages, he was also the protector of travelers and merchants. How much would you weigh on Mercury? If you moved to Mercury you would not weigh as much as you do on Earth. Not because you would lose weight on the space ship, but because Mercury is smaller, and so has less gravity. If you weigh 70 pounds (32 kg) on Earth, you would weigh only about 27 pounds (12 kg) on Mercury. The Planet: Mercury is a world of extremes. Because it is so close to the Sun a visitor could easily cook to death. However, because mercury spins so slowly it gets very cold in the night time, which means a visitor could also freeze to death. We are just starting to understand this world. It looks a lot like our moon, because it has craters and basins. Scientists used to think it acted like the Moon, but we are now learning that Mercury is in fact very different. In March of 2011, NASAs Messenger probe entered Mercury's orbit. It will soon give scientists a lot of new information about Mercury.

Moons: Mercury has no moons. Mercury is so close to the Sun and so small that it has only a very small atmosphere. It has been blown away by the Sun's solar winds. That means that there is almost no air on Mercury. Mercury Venus was the Roman goddess of love and beauty. In Greek her name was Aphrodite. How much would you weigh on Venus? Because Venus and the Earth are almost the exact same size, you would weigh almost exactly the same on either planet. If you weighed 70 pounds (32 kg) on Earth, you would weigh 63 pounds (29 kg) on Venus. The Planet: Venus is a hostile planet. Its thick cloud cover makes it impossible to see the surface, and traps much of the Sun's heat. This extra heat gives Venus the hottest average temperature of all the planets. In many ways Venus is similar to the Earth. It has active volcanoes, venusquakes, mountains and valleys. The major difference is that Venus' atmosphere makes the planet far too hot for life. Moons: Venus has no moons. Because Venus and the Earth are the same size, scientists call Venus Earth's sister planet.

For a long time most scientists thought that Venus had plants, animals, and possibly even people. However, because Venus is so hot, we now know that it is impossible for anything to live there. Venus Earth Earth means: Her name in Greek was Gaea. Earth was the mother of the mountains, valleys, streams and all other land formations. She was married to Uranus. How big is the Earth? The Earth is the biggest of all the terrestrial planets. A terrestrial planet is a dense planet found in the inner Solar System. The Planet: Our planet is an oasis of life in an otherwise desolate universe. The Earth's temperature, weather, atmosphere and many other factors are just right to keep us alive. Moons: The Earth has one moon. Its name is Luna. Scientists use the Earth to study all the other planets. Since no human has ever visited another planet, we have to use what we know about the Earth and try to guess what the other planets must be like. This is called Comparative Planetology. Earth Mars Mars means: Mars was the Roman god of war and agriculture. It may not seem like these two things go together, but they do.

Mars protected those who fought for their communities and stayed home to raise crops for food. How much would you weigh on Mars? If you weighed 70 pounds (32 kg) on the Earth, you would weigh about 27 pounds (12 kg) on Mars. The Planet: Mars excites scientists because its mild temperament is more like the Earth's than any of the other planets. Evidence suggests that Mars once had rivers, streams, lakes, and even an ocean. As Mars' atmosphere slowly depleted into outer space, the surface water began to permanently evaporate. Today the only water on Mars is either frozen in the polar caps or underground. Moons: Mars has two moons, their names are Deimos and Phobos. Mars has much higher mountains and far deeper canyons than the Earth. Mars' biggest canyon would stretch from New York City to Los Angeles on the Earth. That makes the Grand Canyon look tiny. It also has the Solar System's biggest volcano called Olympus Mons. Mars Saturn Saturn means: Saturn was the god of agriculture, he was called Cronus by the Greeks. He is the son of Uranus, and father of Jupiter.

Saturn over threw his father to become king of the gods, but was then over thrown himself by his son Jupiter. How much would you weigh on Saturn? Because Saturn is bigger than the Earth, you would weigh more on Saturn than you do here. If you weigh 70 pounds (32 kg) on Earth you would weigh 74.5 pounds (34 kg) on Saturn. The Planet: Saturn is a favorite object for many observers. Its beautiful rings are 169,800 miles wide (approx 273,266 km). But the rings are amazingly thin. If you turned the rings on their side, they would be able to fit between the goal posts on a football field. In many ways Saturn is similar to Jupiter, but it is much smaller. Under the clouds of methane and helium, the sky gradually turns into liquid until it becomes a giant ocean of liquid chemicals. Moons: Saturn has 53 official moons and 9 provisional (unofficial) moons. The most well-known of Saturn's moons is probably Titan. It is the second largest moon in the Solar System next to Jupiter's Ganymede. Titan is larger than the planet Mercury.

Some of the other moons are Atlas, Calypso, Dione, Enceladus, Hyperion, Iapetus, Janus, Mimas, Phoebe, and Tethys. Saturn has several hundred rings. However, it is not the only planet with rings. Jupiter, Uranus and Neptune also have rings. Saturn Uranus Uranus means: Uranus was the lord of the skies and husband of Earth. He was also the king of the gods until his son Saturn overthrew him. How much would you weigh on Uranus? It would take you many years to fly a rocket to Uranus. When you arrived you would weigh more because Uranus is bigger than the Earth . If you weigh 70 pounds (32 kg) on the Earth, you would weigh 62 pounds (28 kg) on Uranus. The Planet: Uranus is very odd. Unlike all the other planets and most of the moons in our Solar System, Uranus spins on its side. It is believed that long ago a very large object smashed into this planet. The crash was so powerful that it completely changed the direction of Uranus' spin. Uranus may have an ocean of water beneath its clouds.

It has a large rocky core, and because of the tremendous pressure could possibly contain trillions of large diamonds. Uranus is almost identical to the planet Neptune. Moons: Uranus has 21 moons. Five of these moons are large and the rest are smaller. The largest moon is Titania, followed by Oberon, Umbriel, Ariel and Miranda. Some of the smaller moons are named: Belinda, Bianca, Caliban, Cordelia, Cressida, Desdemona, Juliet, Ophelia, Portia, Puck, and Rosalind. Scientists think Uranus has a huge water ocean underneath its clouds. Uranus Neptune Neptune means: Neptune was originally only the god of water, but was later extended to the ocean when he became associated with the Greek god Poseidon. How much would you weigh on Neptune? If you weigh 70 pounds (32 kg) on the Earth, you would weigh 78.5 pounds (36 kg) on Neptune. The Planet: Neptune has a giant storm much like the storm on Jupiter. This storm is often called The Great Dark Spot.

We do not know how long this storm has been active, because it is so far away that we could not get a good view of Neptune until modern times when we began to send robot explorers. For many centuries people did not know that this planet even existed. It was discovered by Johann Galle and Heinrich D'Arrest in 1846. Neptune has six rings which circle the planet. Moons: Neptune has 13 moons that we know of. Because Neptune is so far away, it is difficult to see any of these worlds. There are probably many more moons orbiting this blue planet which we have not yet discovered. Perhaps you will be the astronomer who discovers some of these worlds. The first moon to be discovered was Triton. Triton was discovered by an amateur astronomer in England named William Lassell only 17 days after Neptune was discovered in 1846. The names of the other moons are: Despina, Galatea, Halimede, Laomedeia, Larissa, Naiad, Nereid, Neso, Proteus, Psamathe, Sao, and Thalassa.

Like Uranus, scientists think there is a very large water ocean under Neptune's clouds. Neptune Pluto Pluto means: To the Romans, Pluto was thought to be the god to whom all men must eventually go. They believed him to be the god of the underworld. His name in Greece was Hades. How much would you weigh on Pluto? Because Pluto is so small you would be very light if you visited. If you weigh 70 pounds (32 kg) on Earth, you would only weigh 4 pounds (2.5 kg) on Pluto. The Planet: Pluto is smaller than 7 of the moons in the Solar System. It is about two-thirds smaller than Earth's moon. Because it is so small, many scientists don't consider it a planet at all. In 1999, a group of scientists attempted to re-classify Pluto as a comet. On August 24, 2006, Pluto's status was officially changed from planet to dwarf planet. For decades, children have been taught in school that there are nine planets in our Solar System. However, with this change, there are now only eight planets. Also because of this change, there is a new category of small planets known as plutoids.

The only spacecraft to get somewhat close to Pluto was the Hubble Space Telescope. Hubble was able to take pictures of Pluto and its moons for scientists to study. Little is known about Pluto and its moons because it is so far away. Moons: Pluto has 3 moons. The largest is named Charon. Charon is only slightly smaller than its parent Pluto. For this reason, Pluto and Charon are often called a double system. The Earth and its moon, Luna, are sometimes considered double planets. Pluto's two other moons are called Hydra and Nix. To learn more about Charon Click Here . Pluto is so far away that no satellites have ever been sent there. This means that we have no good pictures of it. All we can do is guess what is must look like. The picture above was taken by the Hubble Space Telescope. It is the most detailed picture we have. INTELLECT: The Solar System The Solar System The creation of our Solar System took place billions of years ago. Our solar system consists of an average star we call the Sun, the planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto.

It includes: the satellites of the planets; numerous comets, asteroids, and meteoroids; and the interplanetary medium. The Sun is the richest source of electromagnetic energy (mostly in the form of heat and light) in the solar system. The Sun The Sun was born in a vast cloud of gas and dust around 5 billion years ago. Over a period of many millions of years, this gas and dust began to fall into a common center under the force of its own gravity. Solar Flares During periods of high solar activity, the Sun commonly releases massive amounts of gas and plasma into its atmosphere. These ejections are known as solar flares. Some solar flares can be truly massive, and contain impressive power. Mercury The planet Mercury is the closest of the planets to the Sun. Because this planet lies so close to the Sun, and as a result somewhat near to the Earth, it is visible to observers on Earth in the night time sky. Because of this, Mercury has become apart of the mythology and legend of almost every culture throughout the history of the Earth. This planet is often called a morning star. This is because Mercury shines brightly in the early morning, just before the sun rises.

It has also been called an evening star for the same reason. Mercury often is visible for a brief period of time just after the Sun sets. Venus The planet Venus has long been one of the most misunderstood of all the inner planets. Like the Earth, Venus has an atmosphere. However, Venus' atmosphere is far thicker than that of the Earth, making it difficult for modern science to penetrate. Interestingly, scientists have recently been able to peek through the thick clouds and get a few glimpses of the surface. There are numerous volcanoes and many mountains that appear misshapen. There is much we still do not know about how this planet looks and what it is like. However, using special instruments and probes scientists have in recent years unlocked many of the secrets long hidden by this mysterious world. In the 1970s, the Soviet Union actually was able to land more than one probe on the surface of Venus. These scientific probes only lasted a few hours before they were destroyed by the intense heat of the planet. These probes were able to take several pictures and send them back to earth for scientists to study. Earth Our planet is the third planet from the sun and is the fifth largest planet.

The Earth's temperature, weather, atmosphere and many other factors are just right to keep us alive. The Earth has one moon. Its name is Luna. Earth was formed 4.54 billion years ago. The earth is expected to continue to support life for another 500 million years. About 71% of the earth is covered with salt water oceans. The moon which started orbiting earth 4.53 years ago controls the oceans tides. Mars Mars excites scientists because its mild temperament is more like the Earth's than any of the other planets. Evidence suggests that Mars once had rivers, streams, lakes, and even an ocean. As Mars' atmosphere slowly depleted into outer space the surface water began to permanently evaporate. Today the only water on Mars is either frozen in the polar caps, or underground. Mars has two moons; their names are Deimos and Phobos. Jupiter Jupiter has at least 63 moons. The four largest and most well-known were discovered by Galileo in the year 1610. Their names are Io, Europa, Ganymede and Callisto.

Some of the other moons are Adrastea, Ananke, Carme, Elara, Himalia, Leda, Lysithea, Metis, Pasiphae, Sinope, and Thebe. Jupiter is by far the largest planet in our Solar System. The Earth could fit inside Jupiter more than 1000 times. Jupiter is a very stormy planet. There are storms found throughout the atmosphere, and most of the storms seem to never end. The many different cloud formations and storms in the atmosphere also make Jupiter a very colorful planet. Jupiter's great red spot, visible in the picture above to the right, is where a giant storm has been raging for at least 300 years. This red spot is also called "The Eye of Jupiter". Saturn Saturn is a favorite object for many observers. Its beautiful rings are 169,800 miles wide, but less thick than a football field. In many ways Saturn is similar to Jupiter, but it is much smaller. Under the clouds of methane and helium the sky gradually turns into liquid until it becomes a giant ocean of liquid chemicals. Saturn has 34 companions moons. Uranus Uranus has 27 moons.

Five of these moons are large, and the rest are smaller. Their names are: Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind, Belinda, Puck, Miranda, Ariel, Umbriel, Titania, Oberon, Caliban, Sycorax, Prospero, Setebos, Stephano, and 1986U10. Uranus is very odd. Unlike all the other planets and most of the moons in our Solar System Uranus spins on its side. It is believed that long ago a very large object smashed into this planet. The crash was so powerful that it completely changed the direction of Uranus' spin. Uranus may have an ocean of water beneath its clouds. It has a large rocky core, and because of the tremendous pressure could possibly contain trillions of large diamonds. Uranus is almost identical to the planet Neptune

Question: Which planet in our solar system was discovered by Johann Galle and Heinrich D’Arrest in 1846?
Answer: Neptune