GAIA, THE ESA SPACE OBSERVATORY FOR ASTROMETRY

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

Joseph likes Astronomy, History and Archaeology. They have been talking about Gaia, the space observatory of the European Space Agency (ESA) launched on a day like today in 2013.

Gaia is a space observatory of the European Space Agency (ESA), launched in 2013 and expected to operate until c. 2022. The spacecraft is designed for astrometry: measuring the positions, distances and motions of stars with unprecedented precision.

The mission aims to construct by far the largest and most precise 3D space catalog ever made, totalling approximately 1 billion astronomical objects, mainly stars, but also planets, comets, asteroids and quasars among others.

The spacecraft will monitor each of its target objects about 70 times over the first five years of the mission to study the precise position and motion of each target, and will keep doing so.

The spacecraft has enough micro-propulsion fuel to operate until about November 2024. As its detectors are not degrading as fast as initially expected, the mission could therefore be extended.

The Gaia targets objects brighter than magnitude 20 in a broad photometric band that covers most of the visual range; such objects represent approximately 1% of the Milky Way population. Additionally, Gaia is expected to detect thousands to tens of thousands of Jupiter-sized exoplanets beyond the Solar System, 500,000 quasars outside our galaxy and tens of thousands of new asteroids and comets within the Solar System.

More information: ESA

The Gaia mission will create a precise three-dimensional map of astronomical objects throughout the Milky Way and map their motions, which encode the origin and subsequent evolution of the Milky Way.

The spectrophotometric measurements will provide the detailed physical properties of all stars observed, characterizing their luminosity, effective temperature, gravity and elemental composition. This massive stellar census will provide the basic observational data to analyze a wide range of important questions related to the origin, structure, and evolutionary history of our galaxy.

The successor to the Hipparcos mission (operational 1989–93), Gaia is part of ESA's Horizon 2000+ long-term scientific program.

Gaia was launched on 19 December 2013 by Arianespace using a Soyuz ST-B/Fregat-MT rocket flying from Kourou in French Guiana.

The spacecraft currently operates in a Lissajous orbit around the Sun–Earth L2 Lagrangian point.

The Gaia space telescope has its roots in ESA's Hipparcos mission (1989–1993). Its mission was proposed in October 1993 by Lennart Lindegren (Lund Observatory, Lund University, Sweden) and Michael Perryman (ESA) in response to a call for proposals for ESA's Horizon Plus long-term scientific programme.

It was adopted by ESA's Science Programme Committee as cornerstone mission number 6 on 13 October 2000, and the B2 phase of the project was authorised on 9 February 2006, with EADS Astrium taking responsibility for the hardware. The name Gaia was originally derived as an acronym for Global Astrometric Interferometer for Astrophysics.

This reflected the optical technique of interferometry that was originally planned for use on the spacecraft. While the working method evolved during studies and the acronym is no longer applicable, the name Gaia remained to provide continuity with the project.

The total cost of the mission is around €740 million (~ $1 billion), including the manufacture, launch and ground operations. Gaia was completed two years behind schedule and 16% above its initial budget, mostly due to the difficulties encountered in polishing Gaia's ten mirrors and assembling and testing the focal plane camera system.

More information: New Atlas

Gaia was launched by Arianespace, using a Soyuz ST-B rocket with a Fregat-MT upper stage, from the Ensemble de Lancement Soyouz at Kourou in French Guiana on 19 December 2013 at 09:12 UTC (06:12 local time). The satellite separated from the rocket's upper stage 43 minutes after launch at 09:54 UTC. 

The craft headed towards the Sun–Earth Lagrange point L2 located approximately 1.5 million kilometres from Earth, arriving there 8 January 2014. The L2 point provides the spacecraft with a very stable gravitational and thermal environment.

There it uses a Lissajous orbit that avoids blockage of the Sun by the Earth, which would limit the amount of solar energy the satellite could produce through its solar panels, as well as disturb the spacecraft's thermal equilibrium. After launch, a 10-metre-diameter sunshade was deployed. The sunshade always faces the Sun, thus keeping all telescope components cool and powering Gaia using solar panels on its surface.

In October 2013 ESA had to postpone Gaia's original launch date, due to a precautionary replacement of two of Gaia's transponders. These are used to generate timing signals for the downlink of science data.

A problem with an identical transponder on a satellite already in orbit motivated their replacement and reverification once incorporated into Gaia. The rescheduled launch window was from 17 December 2013 to 5 January 2014, with Gaia slated for launch on 19 December.

Gaia was successfully launched on 19 December 2013 at 09:12 UTC. About three weeks after launch, on 8 January 2014, it reached its designated orbit around the Sun-Earth L2 Lagrange point (SEL2), about 1.5 million kilometers from Earth.

More information: EO Portal Directory

 Astronomy compels the soul to look upwards
and leads us from this world to another.

Plato

THE ORACLE: FROM MAGNA GRAECIA TO SPRINGFIELD

Donald Trump & Homer Simpson in 2000.

The Grandma is on The Orient Express travelling to Istanbul. She's crossing some lands which were part of the Magna Graecia some centuries ago and it's impossible not thinking in our Mediterranean origins. Greece is the beginning of our history. The relation between Heracle & Hermes and the Mediterranean lands is a great evidence and the Greek influence in our culture nowadays is obvious.

The Grandma has been reading the press with the latest news in The USA. It's not a surprise. It's the consequence of thinking only in the economic markets and forgetting working people. It's impossible to read the news without making a reflexion about the paper of the press nowadays: is the press offering information or creating it? The press is acting like those Greek oracles who guessed the future, not because they had magic powers, but they knew what was going to happen.

Today, we have our own oracle. It's a yellow family who lives in Springfield and they have a glass ball to guess the future.

Dodona, Greece

In classical antiquity, an oracle was a person or agency considered to provide wise and insightful counsel or prophetic predictions or precognition of the future, inspired by the gods. As such it is a form of divination.

The word oracle comes from the Latin verb ōrāre (to speak) and properly refers to the priest or priestess uttering the prediction. In extended use, oracle may also refer to the site of the oracle, and to the oracular utterances themselves, called khrēsmoi (χρησμοί) in Greek.

Oracles were thought to be portals through which the gods spoke directly to people. In this sense they were different from seers (manteis, μάντεις) who interpreted signs sent by the gods through bird signs, animal entrails, and other various methods.

The most important oracles of Greek antiquity were Pythia, priestess to Apollo at Delphi, and the oracle of Dione and Zeus at Dodona in Epirus. Other temples of Apollo were located at Didyma on the coast of Asia Minor, at Corinth and Bassae in the Peloponnese, and at the islands of Delos and Aegina in the Aegean Sea. The Sibylline Oracles are a collection of oracular utterances written in Greek hexameters ascribed to the Sibyls, prophetesses who uttered divine revelations in frenzied states.

In Egypt the goddess Wadjet (eye of the moon) was depicted as a snake-headed woman or a woman with two snake-heads. Her oracle was in the renowned temple in Per-Wadjet (Greek name Buto). The oracle of Wadjet may have been the source for the oracular tradition which spread from Egypt to Greece. 

Oracular inscription on sheet of lead

In Greece the old oracles were devoted to the Mother Goddess. At the oracle of Dodona she will be called Diōnē (literally heavenly), who represents the earth-fertile soil, probably the chief female goddess of the PIE pantheon. Python, daughter (or son) of Gaia was the earth dragon of Delphi represented as a serpent and became the chthonic deity, enemy of Apollo, who slew her and possessed the oracle.

Dodona was another oracle devoted to the Mother Goddess identified at other sites with Rhea or Gaia, but here called Dione. The shrine of Dodona was the oldest Hellenic oracle, according to the fifth-century historian Herodotus and in fact dates to pre-Hellenic times, perhaps as early as the second millennium BC when the tradition probably spread from Egypt. Zeus displaced the Mother goddess and assimilated her as Aphrodite.

It became the second most important oracle in ancient Greece, which later was dedicated to Zeus and to Heracles during the classical period of Greece. 

 

 Everything you need for better future and success has already been written. And guess what? All you have to do is go to the library. 

Henri Frederic Amiel