NEPTUNE IS DISCOVERED AT THE BERLIN OBSERVATORY

Today, The Grandma has received the wonderful visit of Joseph de Ca'th Lon, one of her best friends. 

 

Joseph loves Astronomy and they have been talking about Neptune, the planet that was discovered on a day like today in 1846.

Neptune is the eighth planet from the Sun and the farthest known solar planet. In the Solar System, it is the fourth-largest planet by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times the mass of Earth, and slightly more massive than its near-twin Uranus. 

Neptune is denser and physically smaller than Uranus because its greater mass causes more gravitational compression of its atmosphere. It is referred to as one of the solar system's two ice giant planets, the other one being Uranus.

Being composed primarily of gases and liquids, it has no well-defined solid surface. The planet orbits the Sun once every 164.8 years at an average distance of 30.1 AU (4.5 billion km; 2.8 billion mi). It is named after the Roman god of the sea and has the astronomical symbol ♆, representing Neptune's trident.

Neptune is not visible to the unaided eye and is the only planet in the Solar System found by mathematical prediction rather than by empirical observation. Unexpected changes in the orbit of Uranus led Alexis Bouvard to hypothesise that its orbit was subject to gravitational perturbation by an unknown planet. After Bouvard's death, the position of Neptune was predicted from his observations, independently, by John Couch Adams and Urbain Le Verrier.

More information: NASA

Neptune was subsequently observed with a telescope on 23 September 1846 by Johann Galle within a degree of the position predicted by Le Verrier. Its largest moon, Triton, was discovered shortly thereafter, though none of the planet's remaining 13 known moons were located telescopically until the 20th century.

The planet's distance from Earth gives it a very small apparent size, making it challenging to study with Earth-based telescopes.  

Neptune was visited by Voyager 2, when it flew by the planet on 25 August 1989; Voyager 2 remains the only spacecraft to have visited Neptune. The advent of the Hubble Space Telescope and large ground-based telescopes with adaptive optics has recently allowed for additional detailed observations from afar.

Like Jupiter and Saturn, Neptune's atmosphere is composed primarily of hydrogen and helium, along with traces of hydrocarbons and possibly nitrogen, though it contains a higher proportion of ices such as water, ammonia and methane. However, similar to Uranus, its interior is primarily composed of ices and rock; Uranus and Neptune are normally considered ice giants to emphasise this distinction.

Along with Rayleigh scattering, traces of methane in the outermost regions in part account for the planet's blue appearance. Newest data from the Gemini observatory shows the blue color is more saturated than the one present on Uranus due to thinner haze of Neptune's more active atmosphere.

In contrast to the hazy, relatively featureless atmosphere of Uranus, Neptune's atmosphere has active and visible weather patterns. For example, at the time of the Voyager 2 flyby in 1989, the planet's southern hemisphere had a Great Dark Spot comparable to the Great Red Spot on Jupiter. More recently, in 2018, a newer main dark spot and smaller dark spot were identified and studied.

In addition, these weather patterns are driven by the strongest sustained winds of any planet in the Solar System, with recorded wind speeds as high as 2,100 km/h. Because of its great distance from the Sun, Neptune's outer atmosphere is one of the coldest places in the Solar System, with temperatures at its cloud tops approaching −218 °C. Temperatures at the planet's centre are approximately 5,100 °C.

Neptune has a faint and fragmented ring system (labelled "arcs"), which was discovered in 1984, then later confirmed by Voyager 2.

More information: NASA

 What I want to look at with Webb is
what we call ice giants in our solar system
-the planets Neptune and Uranus.

Heidi Hammel

'VOYAGER 2' IN CAN ROIG OBSERVATORY, LLAGOSTERA

Voyager 2, 1977 / Visiting Can Roig Observatory

Today, The Grandma has visited Can Roig Astronomical Observatory in Llagostera, Girona.

She has shared this visit with Joseph de Ca'th Lon, his closer friend, who is a fan of Astronomy and who has explained her lots of things about Voyager 2, the space probe launched by NASA on a day ike today in 1977.

During the travel from Barcelona to Llagostera, in the county og Gironès, in Girona, The Grandma has studied a new lesson of her Ms. Excel course.

Chapter 14. Schemes and views (II) (Spanish Version)

Voyager 2 is a space probe launched by NASA on August 20, 1977, to study the outer planets. Part of the Voyager program, it was launched 16 days before its twin, Voyager 1, on a trajectory that took longer to reach Jupiter and Saturn but enabled further encounters with Uranus and Neptune. It is the only spacecraft to have visited either of these two ice giant planets.

Its primary mission ended with the exploration of the Neptunian system on October 2, 1989, after having visited the Uranian system in 1986, the Saturnian system in 1981, and the Jovian system in 1979.

Voyager 2 is now in its extended mission to study the outer reaches of the Solar System and has been operating for 42 years and 3 days as of 23 August 2019. It remains in contact through the NASA Deep Space Network.

More information: Jet Propulsion Laboratory-NASA

At a distance of 120 AU from the Sun as of February 25, 2019, moving at a velocity of 15.341 km/s relative to the Sun, Voyager 2 is the fourth of five spacecraft to achieve the escape velocity that will allow them to leave the Solar System.

The probe left the heliosphere for interstellar space on November 5, 2018, becoming the second artificial object to do so, and has begun to provide the first direct measurements of the density and temperature of the interstellar plasma.

Voyager 2: Interstellar

In the early space age, it was realized that a periodic alignment of the outer planets would occur in the late 1970s and enable a single probe to visit Jupiter, Saturn, Uranus, and Neptune by taking advantage of the then-new technique of gravity assists.

NASA began work on a Grand Tour, which evolved into a massive project involving two groups of two probes each, with one group visiting Jupiter, Saturn, and Pluto and the other Jupiter, Uranus, and Neptune. The spacecraft would be designed with redundant systems to ensure survival through the entire tour.

By 1972 the mission was scaled back and replaced with two Mariner-derived spacecraft, the Mariner Jupiter-Saturn probes. To keep apparent lifetime program costs low, the mission would include only flybys of Jupiter and Saturn, but keep the Grand Tour option open. As the program progressed, the name was changed to Voyager.

The primary mission of Voyager 1 was to explore Jupiter, Saturn, and Saturn's moon, Titan. Voyager 2 was also to explore Jupiter and Saturn, but on a trajectory that would have the option of continuing on to Uranus and Neptune, or being redirected to Titan as a backup for Voyager 1. Upon successful completion of Voyager 1's objectives, Voyager 2 would get a mission extension to send the probe on towards Uranus and Neptune.

More information: Science News

Constructed by the Jet Propulsion Laboratory (JPL), Voyager 2 included 16 hydrazine thrusters, three-axis stabilization, gyroscopes and celestial referencing instruments (Sun sensor/Canopus Star Tracker) to maintain pointing of the high-gain antenna toward Earth. Collectively these instruments are part of the Attitude and Articulation Control Subsystem (AACS) along with redundant units of most instruments and 8 backup thrusters. The spacecraft also included 11 scientific instruments to study celestial objects as it traveled through space.

Built with the intent for eventual interstellar travel, Voyager 2 included a large, 3.7 m parabolic, high-gain antenna to transceive data via the Deep Space Network on the Earth. Communications are conducted over the S-band, about 13 cm wavelength, and X-band, about 3.6 cm wavelength, providing data rates as high as 115.2 kilobits per second at the distance of Jupiter, and then ever-decreasing as the distance increased, because of the inverse-square law. When the spacecraft is unable to communicate with Earth, the Digital Tape Recorder (DTR) can record about 64 kilobytes of data for transmission at another time.

Voyager 1 & Voyager 2

Voyager 2 is equipped with 3 MHW RTG. Each RTG includes 24 pressed plutonium oxide spheres, and provided enough heat to generate approximately 157 W of electrical power at launch. Collectively, the RTGs supplied the spacecraft with 470 watts at launch, halving every 87.7 years, and will allow operations to continue until at least 2020.

The Voyager 2 probe was launched on August 20, 1977, by NASA from Space Launch Complex 41 at Cape Canaveral, Florida, aboard a Titan IIIE/Centaur launch vehicle. Two weeks later, the twin Voyager 1 probe was launched on September 5, 1977. However, Voyager 1 reached both Jupiter and Saturn sooner, as Voyager 2 had been launched into a longer, more circular trajectory.

Following a mid-course correction in 1987, Voyager 2's closest approach to Neptune occurred on August 25, 1989. Through repeated computerized test simulations of trajectories through the Neptunian system conducted in advance, flight controllers determined the best way to route Voyager 2 through the Neptune-Triton system.

More information: CSIRO

Since the plane of the orbit of Triton is tilted significantly with respect to the plane of the ecliptic, through mid-course corrections, Voyager 2 was directed into a path about 4950 kilometers above the north pole of Neptune. Five hours after Voyager 2 made its closest approach to Neptune, it performed a close fly-by of Triton, the larger of Neptune's two originally known moons, passing within about 40,000 kilometers.

Voyager 2 discovered previously unknown Neptunian rings, and confirmed six new moons: Despina, Galatea, Larissa, Proteus, Naiad and Thalassa. While in the neighborhood of Neptune, Voyager 2 discovered the Great Dark Spot, which has since disappeared, according to observations by the Hubble Space Telescope.

The Great Dark Spot was later hypothesized to be a region of clear gas, forming a window in the planet's high-altitude methane cloud deck.

With the decision of the International Astronomical Union to reclassify Pluto as a dwarf planet in 2006, the flyby of Neptune by Voyager 2 in 1989 became the point when every known planet in the Solar System had been visited at least once by a space probe.

More information: Los Angeles Times

According to 'M' theory, ours is not the only universe.

Instead, 'M' theory predicts that a great many universes

were created out of nothing.

Stephen Hawking

DISCOVERING THE SUBWORLD IN 'LA COVA DE NEPTÚ'

Going down the 654-step escala del cabirol

Today, Joseph de Ca'th Lon and his friends are visiting La Cova de Neptú in Sardìnnia because loves Archaeology and Speleology and this cave is a wonderful natural place to enjoy both of them.

During the travel from the beautiful town of Casteddu to La Cova de Neptú, The Grandma has been studying a new lesson of her interesting and amazing Elementary Language Practice manual (Grammar 11).

More information: Past Simple of Be I  & II

La Cova de Neptú in Catalan or Grotte di Nettuno in Italian (Neptune's Grotto) is a stalactite cave near the town of L'Alguer on the island of Sardìnnia. 

The cave was discovered by local fishermen in the 18th century and has since developed into a popular tourist attraction. The grotto gets its name from the Roman god of the sea, Neptune.

The entrance to the grotto lies only around a metre above the sea level at the foot of the 110-metre-high Capo Caccia cliffs and the cave can therefore only be visited when the waters below are calm. 

Inside La Cova de Neptú, an amazing place

A stairway cut into the cliff in 1954, the 654-step escala del cabirol, goat's steps, leads from a car park at the top of the cliff down to the entrance. The grotto is also accessible via a short boat trip from the port of L'Alguer; these trips are arranged hourly during the summer, but less frequently during spring and autumn.

Two other grottoes lie nearby, the Green grotto, which is not open to tourists, and the Grotta di Ricami, which is only accessible from the sea. Under water all around there are many big under water marine caves, paradise for the scuba-diving fans, the bigger and the most famous is the Nereo Cave, visited each year by thousands of scuba divers.

More information: Sardegna Turismo

The combined length of the cave system is estimated to be around 4 kilometers, but only a few hundred metres are accessible to the public. Inside are passages of lit stalactite and stalagmite formations, and a 120-metre-long saltwater lake, which is at sea level. The cave was once a habitat for the Mediterranean monk seal, which has become extinct in the area.

Tourists visiting La Cova de Neptú are given guided tours and led single-file through a lit pathway, with tour guides providing information about the cave in Catalan, Italian and English. The grotto is widely visited, and during the peak tourist season in August, can contain around 200 people at a time.

Going up the 654-step escala del cabirol

La Cova de Neptú was the set of the movie Island of the Fishmen, filmed in the summer of 1978. For approximately two months the Grotto was transformed into a gigantic set. The science fiction movie starred Barbara Bach, and was under the direction of Sergio Martino.

Neptune, in Latin Neptūnus, was the god of freshwater and the sea in Roman religion. He is the counterpart of the Greek god Poseidon. In the Greek-influenced tradition, Neptune was the brother of Jupiter and Pluto; the brothers presided over the realms of Heaven, the earthly world, and the Underworld. Salacia was his wife.

Depictions of Neptune in Roman mosaics, especially those of North Africa, are influenced by Hellenistic conventions. Neptune was likely associated with fresh water springs before the sea. Like Poseidon, Neptune was worshipped by the Romans also as a god of horses, under the name Neptunus Equester, a patron of horse-racing.

The etymology of Latin Neptunus is unclear and disputed. The ancient grammarian Varro derived the name from nuptus i.e. covering (opertio), with a more or less explicit allusion to the nuptiae, marriage of Heaven and Earth.

More information: Grotte di Nettuno

In archaeology, context is the basis of many discoveries 

that are imputed to the deliberate workings of intelligence. 

If I find a rock chipped in such a way as to give it a sharp edge,

and the discovery is made in a cave, 

I am seduced into ascribing this to tool use by distant,

fetid and furry ancestors.

Seth Shostak

TRITON: THE LARGEST NATURAL SATELLITE OF NEPTUNE

The Grandma & Joseph in the Ebre Observatory

Joseph de Ca'th Lon has invited The Grandma to spend some days in the Ebre lands. He wants to go to the Ebre Observatory with her to talk about Triton, the Neptune's moon that was discovered on a day like today in 1846.

During the travel to Roquetes, where the Ebre Observatory is located, The Grandma has studied a new lesson of her First Certificate Language Practice manual (Vocabulary 7).

She has been also thinking in her Majorcan friends, especially on a day like today, where they are suffering the terrible consequences of an enormous flood with mortal victims and many scenes of desolation. The Grandma's heart and her thoughts are today in this wonderful and special island, and with its people, who always accompanies her wherever she goes.

More information: Food, restaurants and cooking I & II

Triton is the largest natural satellite of the planet Neptune and the first Neptunian moon to be discovered on October 10, 1846 by English astronomer William Lassell.

It is the only large moon in the Solar System with a retrograde orbit, an orbit in the direction opposite to its planet's rotation. It is 2,710 kilometres in diameter, the seventh-largest moon in the Solar System.

Triton is thought to have been a dwarf planet captured from the Kuiper belt because of its retrograde orbit and composition similar to Pluto's. It has a surface of mostly frozen nitrogen, a mostly water-ice crust, an icy mantle, and a substantial core of rock and metal. The core makes up two-thirds of its total mass. It has a mean density of 2.061 g/cm3  and is composed of approximately 15–35% water ice.

Triton

Triton is one of the few moons in the Solar System known to be geologically active, the others being Jupiter's Io and Europa, and Saturn's Enceladus and Titan.

As a consequence, its surface is relatively young with few obvious impact craters, and a complex geological history revealed in intricate cryovolcanic and tectonic terrains. Part of its surface has geysers erupting sublimated nitrogen gas, contributing to a tenuous nitrogen atmosphere less than 1/70,000 the pressure of Earth's atmosphere at sea level. It is the second-largest planetary moon in relation to its primary, after Earth's moon. 

Triton was discovered by British astronomer William Lassell on October 10, 1846, just 17 days after the discovery of Neptune. He discovered Triton with his self-built, 61 cm telescope.

A brewer by trade, Lassell began making mirrors for his amateur telescope in 1820. When John Herschel received news of Neptune's discovery, he wrote to Lassell suggesting he search for possible moons. Lassell did so and discovered Triton eight days later. Lassell also claimed to have discovered rings. Although Neptune was later confirmed to have rings, they are so faint and dark that it is doubtful that he actually saw them.

More information: Observatori de l'Ebre

Triton is named after the Greek sea god Triton or Τρίτων, the son of Poseidon, the Greek god comparable to the Roman Neptune. The name was first proposed by Camille Flammarion in his 1880 book Astronomie Populaire, and was officially adopted many decades later.

Until the discovery of the second moon Nereid in 1949, Triton was commonly referred to as the satellite of Neptune. Lassell did not name his own discovery; he later successfully suggested the name Hyperion, previously chosen by John Herschel, for the eighth moon of Saturn when he discovered it.

The surface of Triton

Moons in retrograde orbits cannot form in the same region of the solar nebula as the planets they orbit, so Triton must have been captured from elsewhere.

It might therefore have originated in the Kuiper belt, a ring of small icy objects extending from just inside the orbit of Neptune to about 50 AU from the Sun. 

Thought to be the point of origin for the majority of short-period comets observed from Earth, the belt is also home to several large, planet-like bodies including Pluto, which is now recognized as the largest in a population of Kuiper belt objects, the plutinos, locked in orbital step with Neptune.

More information: NASA

Triton is only slightly larger than Pluto and nearly identical in composition, which has led to the hypothesis that the two share a common origin.

The proposed capture of Triton may explain several features of the Neptunian system, including the extremely eccentric orbit of Neptune's moon Nereid and the scarcity of moons as compared to the other giant planets.

Triton's initially eccentric orbit would have intersected orbits of irregular moons and disrupted those of smaller regular moons, dispersing them through gravitational interactions.

Triton's eccentric post-capture orbit would have also resulted in tidal heating of its interior, which could have kept Triton fluid for a billion years; this inference is supported by evidence of differentiation in Triton's interior. This source of internal heat disappeared following tidal locking and circularization of the orbit.

More information: Space

Man is a microcosm, or a little world, because he is an extract 

from all the stars and planets of the whole firmament, 

from the earth and the elements; and so he is their quintessence.

Paracelsus

VOYAGER 1: THE INTERSTELLAR MISSION

Voyager 1

We wanted to believe. 

We wanted to call out.

On August 20th and September 5th, 1977, two spacecraft were launched from the Kennedy Space Flight Center, Florida. They were called Voyager.

Each one carries a message: I send greetings on behalf of the people of our planet. We step out of our solar system into the universe, seeking only peace, to teach...

A gold-plated record depicting images, music and sounds of our planet, arranged so that it may be understood if ever intercepted by a technologically mature extraterrestrial civilization.

Thirteen years after its launch, Voyager One passed the orbital plane of Neptune and essentially leaving our solar system. Within that time, there were no further messages sent. Nor are any planned.

More information: Voyager. The Interstellar Mission (NASA)

We wanted to listen.

On October 12th, 1992, NASA initiated the high-resolution microwave survey. 

A decade long-search by radio telescope, scanning ten million frequencies for any transmission by extraterrestrial intelligence.

Less than one year later, first-term Nevada Senator Richard Bryan successfully championed an amendment which terminated the project.

We are building our future in peace and harmony.

We won't wander alone through outer space.

 The Grandma