The European Space agency’s deep-space probe Gaia recorded data logs indicating the position of 1.1 billion stars, about ONE PERCENT of the Milky Way’s inventory, and will eventually track all the stars in its inventory to be released by 2022. The aim of the Gaia mission is to create a complete catalog of the Milky Way’s stars, their brightness and their movement in order to determine their age.
Wikileaks describes the exact mission as: “to construct the largest and most precise 3D space catalog ever made and totaling approximately 1 billion astronomical objects, mainly stars but also planets, comets, asteroids and quasars among others. The spacecraft will monitor each of its target stars about 70 times over a period of five years to study the precise motion of each star relative to the Milky Way galaxy.” The second data release, scheduled for the fourth quarter of 2017, will include positions, parallaxes and proper motions, red and blue photometric data, and radial velocity measurements for many simple cases. The third data release, scheduled for 2018, will include orbital solutions for many binary stars and classifications for spectroscopically “well behaved” objects. The fourth data release, scheduled for 2019, will include variable star classifications, solar system results, and non single-star catalogues.
The Gaia space mission has the following objectives:
To determine the intrinsic luminosity of a star requires knowledge of its distance. One of the few ways to achieve this without physical assumptions is through the star’s parallax. Ground-based observations would not measure such parallaxes with sufficient precision due to the effects of the atmosphere and instrumental biases. For instance, Cepheid variables are used as standard candles to measure distances to galaxies, but the accuracy in their own distance measurement is poor. Thus, quantities depending on them, such as the speed of expansion of the universe, remain inaccurate. Measuring their distances accurately has a great impact on the understanding of the other galaxies and thus the whole cosmos (see cosmic distance ladder).
Observations of the faintest objects will provide a more complete view of the stellar luminosity function. Gaia will observe 1 billion stars and other bodies, representing 1% of such bodies in the Milky Way galaxy. All objects up to a certain magnitude must be measured in order to have unbiased samples.
To permit a better understanding the more rapid stages of stellar evolution (such as the classification, frequency, correlations and directly observed attributes of rare fundamental changes and of cyclical changes). This has to be achieved by detailed examination and re-examination of a great number of objects over a long period of operation. Observing a large number of objects in the galaxy is also important to understand the dynamics of our galaxy.
Measuring the astrometric and kinematic properties of a star is necessary in order to understand the various stellar populations, especially the most distant.
In announcing the release, Alvaro Giménez, ESA’s director of science, said that it gives the first glimpse of a data set that will “revolutionize our understanding of how stars are distributed and move across our galaxy. This data will sharpen our picture of the galaxy’s structure, including the “bar” at its center and outlier groups of fast-moving stars that are thought to be remnants of mergers with smaller galaxies.”
Okay, the really interesting backstory is Gaia’s investigation into a) the Milky Way bar (LOL !) Dark Bar) , b) Dark Matter- as investigated by Harvard’s Dr. Lisa Randall and others, c) so-called “Variable Stars” which “throb” in mysterious patterns, d) “wobbling planets” (like Earth) which are being impacted by competing gravitational pulls, e) “exoplanets” or bodies outside the Milky Way, and f) a Twitter-enabled field called “intrastronomy.” This field is defined by the obsession of astronomers to track close in anaomalies such as “Planet X” (or Nibiru – “Astronomers are using Gaia’s new stellar position measurements to work out the precise distances to these planets and sharing their plots on Twitter,” reports WIRED from Quanta Magazine. Some astronomers say Planet X will arrive in our near earth orbit in 2017 and is unnerving…
In Dark Matter and the Dinosaurs, Dr. Randall hypothesizes the demise of the dinosaurs was caused by a comet strike on the earth.
Sixty-six million years ago, an object the size of a city descended from space to crash into Earth, creating a devastating cataclysm that killed off the dinosaurs, along with three-quarters of the other species on the planet. What was its origin? In Dark Matter and the Dinosaurs, Lisa Randall proposes it was a comet that was dislodged from its orbit as the Solar System passed through a disk of dark matter embedded in the Milky Way. In a sense, it might have been dark matter that killed the dinosaurs. Working through the background and consequences of this proposal, Randall shares with us the latest findings—established and speculative—regarding the nature and role of dark matter and the origin of the Universe, our galaxy, our Solar System, and life, along with the process by which scientists explore new concepts.
Picture credit: Artist’s impression of the Gaia spacecraft – ESA
|Mission type||Astrometric observatory|
|Mission duration||planned: 5 years
elapsed: 2 years, 8 months and 30 days
|Launch mass||2,029 kg (4,473 lb)|
|Dry mass||1,392 kg (3,069 lb)|
|Payload mass||710 kg (1,570 lb)|
|Dimensions||4.6 m × 2.3 m (15.1 ft × 7.5 ft)|
|Start of mission|
|Launch date||19 December 2013, 09:12:14 UTC|