MAYTE VISITS TORTOSA, THE CAPITAL OF BAIX EBRE

Today, The Grandma has received news from her closest friend Mayte, who has visited Tortosa, the Catalan city, capital of Baix Ebre.

Tortosa is the capital of the comarca of Baix Ebre, in Catalonia.

Tortosa is located at 12 metres above sea level, by the Ebre river, protected on its northern side by the mountains of the Cardó Massif, of which Buinaca, one of the highest peaks, is located within Tortosa's municipal boundary.

Before Tortosa, across the river, rise the massive Ports de Tortosa-Beseit mountains. The area around Mont Caro and other high summits are often covered with snow in the winter.

Tortosa, from Latin Dertusa or Dertosa, via Arabic طرطوشة Ṭurṭūshah, is probably identical to the ancient Hibera, capital of Ilercavonia. This may be the ancient settlement the remains of which have been found on the hill named Castell de la Suda. In Roman times, the town took the name Dertosa, in Ancient Greek Δέρτωσσα.

Tortosa was occupied in about 714, during the Arab conquest of the Visigothic Kingdom. It remained under Muslim rule for more than 400 years. King Louis the Pious laid siege to Tortosa in 808-809, but although the city submitted he did not manage to occupy it.

The city was conquered by the Count Ramon Berenguer IV of Barcelona in 1148, as part of the Second Crusade. Because of the crusading appeal made by Pope Eugene III and his representative Nicholas Brakespear (the future Pope Hadrian IV), the siege received the aid of crusaders from multiple nationalities (Genovese, Anglo-Normans, Normans, Occitans, Germans, Flemish and Dutch), who were on their way to the Holy Land. The siege of Tortosa was narrated by the Genovese chronicler and diplomat Caffaro.

After its conquest, the city and its territory were divided among the victors, with multiple lands being granted to foreign crusaders and to the military and religious orders.

Formerly there was a railway line between Tortosa and Alcañiz, opening a communication gate between this region and Aragon. Construction work began in 1891, but it was haphazard and the first trains between Alcañiz and Tortosa began only in 1942. The last stretch between Tortosa and Sant Carles de la Ràpita was never completed before the line was terminated by Renfe in 1973.

More information: Tortosa Turisme

The most beautiful places in Tortosa are:

-Castle of Sant Joan or Suda. Commanding the city from a 59-metre-high (194-foot) hill. Though the Romans were the first to fortify the place, the current structure dates to Muslim Caliph Abd ar-Rahman III. After the conquest by Ramon Berenguer IV, Count of Barcelona, in 1148, it became a residence of the Montcada and the Knights Templar, and from the 13th century it became a royal mansion.
The most interesting sights in the city are:

-The Cathedral. Begun in 1347 and consecrated in 1597.

-Bishop Palace.

-The Royal Schools. Founded by Charles V for the education of the Moors, are one of the best examples of Renaissance civil architecture in Catalonia.

-The College of Sant Jaume i Sant Maties. It currently houses the local historical archive of Baix Ebre.

-The College of Sant Domènec i Sant Jordi.

-The church of Sant Domènec. Now the Renaissance Interpretation Centre.

-Convent of Santa Clara. Founded in 1283.

-The Rose street. Despuig Palace (14th century), Oriol Palace and Capmany Palace.

-Oliver de Boteller Palace (15th century)

-Walls and fortresses. Tenasses, Sitjar and Orleans.

-Architecture of the nineteenth and twentieth centuries.

-Air-raid shelter number 4 (Spanish Civil War) in Ernest Hemingway Street.

More information: Catalunya

 Ferit estic de mots i de silencis,
de trossejada argila, asclades fustes,
poderoses forestes desolades.

I am wounded by words and silences,
of crushed clay, wooden screeds,
mighty desolate forests.

Gerard Vergés

51 PEGASI B, THE EXTRASOLAR PLANET IN ROQUETES

The Grandma & Joseph visit L'Observatori de l'Ebre

Today, The Grandma has visited Roquetes, a beautiful town in El Baix Ebre County, in Tarragona. 

The Grandma has visited accompanied by Joseph de Ca'th Lon, her closer friend. They have arrived to visit L'Observatori de l'Ebre, the astronomical centre that is sited there.

Joseph has explained lots of things to The Grandma. They have been talking about planets and paying a lot of attention to the first planet orbiting another sun, 51 Pegasi b that was discovered on a day like today in 1995.

The Observatori de l’Ebre (OE) is a Research Institute founded by the Society of Jesus in 1904 to study Sun-Earth relationships. Over the years it has excelled in the study of earth currents, atmospheric electricity, seismology, solar and geomagnetic activity, and the terrestrial Ionosphere, and continues to do so today in the latter two fields.

More information: L'Observatori de L'Ebre

The OE is governed by a Non Profit Foundation. At present it forms part of the Ramon Llull University (URL) as a University Institute. It is located in Roquetes, in El Baix Ebre, Tarragona. The town is located on the eastern side of the Ports de Tortosa-Beseit. A great part of its municipal territory is located in the Els Ports Natural Park, including many important peaks of the Ports de Tortosa-Beseit Range, such as Mont Caro and Castell de l'Airosa.

51 Pegasi b, abbreviated 51 Peg b, unofficially dubbed Bellerophon, later formally named Dimidium, is an extrasolar planet approximately 50 light-years away in the constellation of Pegasus. It was the first exoplanet to be discovered orbiting a main-sequence star, the Sun-like 51 Pegasi, and marked a breakthrough in astronomical research. It is the prototype for a class of planets called hot Jupiters. In 2017, traces of water were discovered in the planet's atmosphere.

51 Pegasi is the Flamsteed designation of the host star. The planet was originally designated 51 Pegasi b by Michel Mayor and Didier Queloz, who discovered the planet on December 1995. The following year it was unofficially dubbed Bellerophon by astronomer Geoffrey Marcy, who followed the convention of naming planets after Greek and Roman mythological figures. Bellerophon was a figure from Greek mythology who rode the winged horse Pegasus.

51 Pegasi b

In July 2014, the International Astronomical Union launched a process for giving proper names to certain exoplanets and their host stars. The process involved public nomination and voting for the new names.

In December 2015, the IAU announced the winning name for this planet was Dimidium. The name was submitted by the Astronomische Gesellschaft Luzern (German for Astronomical Society of Lucerne), Switzerland. Dimidium is Latin for half, referring to the planet's mass of at least half the mass of Jupiter.

The exoplanet's discovery was announced on October 6, 1995, by Michel Mayor and Didier Queloz of the University of Geneva in the journal Nature. They used the radial velocity method with the ELODIE spectrograph on the Observatoire de Haute-Provence telescope in France and made world headlines with their announcement.

More information: Exoplanets NASA

 
The planet was discovered using a sensitive spectroscope that could detect the slight and regular velocity changes in the star's spectral lines of around 70 metres per second. These changes are caused by the planet's gravitational effects from just 7 million kilometres' distance from the star.

Within a week of the announcement, the planet was confirmed by another team using the Lick Observatory in California.

This was the first discovery of an exoplanet orbiting a Sun-like star, the first exoplanet discovery was made by Aleksander Wolszczan in 1992, around pulsar PSR 1257. It marked a turning point and forced astronomers to accept that giant planets could exist in short-period orbits.

Once astronomers realized that it was worth looking for giant planets with the currently available technology, much more telescope time was devoted to radial velocity planet searches, and hence many more exoplanets in the Sun's neighborhood were discovered.

More information: Earth Sky

After its discovery, many teams confirmed the planet's existence and obtained more observations of its properties. It was discovered that the planet orbits the star in around 4 days. It is much closer to it than Mercury is to the Sun, moves at an orbital speed of 136 km/s, yet has a minimum mass about half that of Jupiter, about 150 times that of the Earth.

Earth & 51 Pegasi b & Jupiter Comparison

At the time, the presence of a huge world so close to its star was not compatible with theories of planet formation and was considered an anomaly. However, since then, numerous other hot Jupiters have been discovered and astronomers are revising their theories of planet formation to account for them by studying orbital migration.

Assuming the planet is perfectly grey with no greenhouse or tidal effects, and a Bond albedo of 0.1, the temperature would be approximately 1000°. This is between the predicted temperatures of HD 189733 b and HD 209458 b (1180–1392 K), before they were measured.

In the report of the discovery, it was initially speculated that 51 Pegasi b was the stripped core of a brown dwarf of a decomposed star and was therefore composed of heavy elements, but it is now believed to be a gas giant. It is sufficiently massive that its thick atmosphere is not blown away by the star's solar wind.

More information: The Atlantic

51 Pegasi b probably has a greater radius than that of Jupiter despite its lower mass. This is because its superheated atmosphere must be puffed up into a thick but tenuous layer surrounding it. Beneath this, the gases that make up the planet would be so hot that the planet would glow red. Clouds of silicates may exist in the atmosphere.

The planet is tidally locked to its star, always presenting the same face to it. The planet, with Upsilon Andromedae b, was deemed a candidate for direct imaging by Planetpol. It is also a candidate for near-infrared characterisation.... with the VLTI Spectro-Imager.

The first ever direct detection of the visible light spectrum reflected from an exoplanet has been made by an international team of astronomers on 51 Pegasi b. The astronomers studied light from 51 Pegasi b using the High Accuracy Radial velocity Planet Searcher (HARPS) instrument at the European Southern Observatory's La Silla Observatory in Chile.

More information: Solstation

It's been said that astronomy is a humbling and,

I might add, a character-building experience.

Carl Sagan

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