ESA’s (European Space Agency) Gaia spacecraft has created the most accurate and detailed map of the Milky Way galaxy (and beyond) to date. The map includes high-precision measurements of nearly 1.7 billion stars and reveals previously unseen details of our home Galaxy. It is the second iteration of the map and published by ESA on April 25, 2018.
The new data release, which covers the period between 25 July 2014 and 23 May 2016, pins down the positions of nearly 1.7 billion stars (the Milky Way contains between 200 and 400 billion stars), and with much greater precision. For some of the brightest stars in the survey, the level of precision equates to Earth-bound observers being able to spot a Euro coin lying on the surface of the Moon.
The video below, published by Quartz channel titled shows the most detailed and accurate star map of the Milky Way galaxy ever made.
Here is the comparison between Gaia’s first (September 2016, left) and second (April 2018, right) data releases:
The virtual journey starts by looking back at the Sun, moving away, and traveling between the stars.
A comparison between the two views shows the huge increase in the number of stars and distances from the Sun between the two data releases: the view on the left is based on the 3D position of 1.4 million stars for which parallaxes had been estimated using the Tycho-Gaia astrometric solution (TGAS) as part of the first Gaia data release, published in 2016.
The view on the right is based on the 3D position of nearly 97 million stars from the second data release, published in 2018. The majority of these stars have the most accurate parallax measurements in the dataset, which can be used to directly estimate distances to individual stars.
Gaia is a space observatory of the European Space Agency (ESA) designed for astrometry: measuring the positions and distances of stars with unprecedented precision. The mission aims to construct the largest and most precise 3D space catalog ever made, totaling approximately 1 billion astronomical objects, mainly stars, but also planets, comets, asteroids and quasars among others.
The spacecraft was launched on December 19, 2013, with a planned mission duration of five years and possible extension by one to four years. Gaia will monitor each of its target objects about 70 times over a period of five years to study the precise position and motion of each target. The spacecraft has enough consumables to operate for approximately nine years, and its detectors are not degrading as fast as initially expected.
The mission could, therefore, be extended. The Gaia targets represent approximately 1% of the Milky Way population with all stars brighter than magnitude 20 in a broad photometric band that covers most of the visual range. Additionally, Gaia is expected to detect thousands to tens of thousands of Jupiter-sized exoplanets beyond the Solar System, at least 500,000 quasars, and tens of thousands of new asteroids and comets within the Solar System.
ESA Director of Science Günther Hasinger says: “The observations collected by Gaia are redefining the foundations of astronomy. Gaia is an ambitious mission that relies on a huge human collaboration to make sense of a large volume of highly complex data. It demonstrates the need for long-term projects to guarantee progress in space science and technology and to implement even more daring scientific missions of the coming decades.”
- “Gaia Creates Richest Star Map Of Our Galaxy – And Beyond” on ESA (European Space Agency) Science & Technology website
- “This is the most accurate map of the sky to date, showing 1.7 billion stars” on Quartz
- “Gaia’s Sky in Color” on ESA (European Space Agency) Science & Technology website
- Gaia (spacecraft) on Wikipedia
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