3D Map of the Galaxy

One Billion Stars, 30,000 Light Years, And Petabytes Of Data
John Foley John Foley

A mission by the European Space Agency to measure and map the Milky Way promises to give astronomers a precise, detailed, and three-dimensional view of our galaxy. The five-year project will generate more than a petabyte of data on the makeup, position, motion, and other characteristics of a billion stars.

The European Space Agency (ESA) launched its data-collecting satellite—equipped with two telescopes, photon detectors, video processing unit, Sun shield, and other instruments—on December 19. In early January, the satellite, called Gaia, arrived at a point in space 1.5 million kilometers from Earth known as “L2,” from which it will carry out its surveillance of the Galaxy.

Gaia will measure the spectra and light intensity of stars and determine their velocity using distances and motions. It will look for planets (by detecting “tiny wobbles” in a host star’s position), exploding stars, failed stars known as brown dwarfs, asteroids, comets, and “Planet X,” a hypothetical tenth planet in our solar system.

In doing so, ESA’s satellite will generate huge volumes of data. “It will single handedly increase the data we possess about where stars are located in space by thousands of times compared to all previous such measurements in history,” writes the Boston Globe.

The Gaia Data Processing and Analysis Consortium, a group of more than 400 scientists at institutions across Europe, will use the data to study the solar system, galactic astronomy, cosmology, and more. “The data processing ground segment is a fundamental element of the mission,” according to ESA.

The astrometry data collected by Gaia will augment scientific observations made by powerful ground-based telescopes. The University of Cambridge’s Institute of Astronomy recently reported that new evidence shows that older stars are in the inner regions of the Milky Way and younger stars in the outer regions, lending support to theories that “our galaxy grew from the inside-out.”
The Italian National Institute of Astrophysics (Istituto Nazionale di Astrofisica, INAF), with the support of the Italian Space Agency (ASI), is using Oracle ORCL +1.07% Database and Oracle Enterprise Manager to support this research. INAF is responsible for managing the astronomical data generated by the satellite, which will be stored at the Italian Data Processing Center.

How much data are we talking about? The mission is expected to perform 100 billion elementary observations, resulting in a petabyte (a thousand terabytes) of data.

INAF and ALTEC—which supplies engineering and logistic services to the International Space Station and operates the Italian Data Processing Center—have developed a technology infrastructure based on three instances of Oracle Database (for development, production and archiving) for the mission. INAF is using Oracle Advanced Compression to squeeze all that data to manageable sizes and to lower costs and shorten backup times.

“Our activity within the Gaia mission will provide a huge volume of information, a very precious heritage of astronomical data that will have to be stored for the whole 21st century and beyond,” said Roberto Morbidelli (INAF), Scientific Operation Manager at the Italian Data Processing Center.

Xavier Verhaeghe, Vice President of Technology and Big Data with Oracle EMEA, said the INAF’s choice of Oracle’s platform will demonstrate the feasibility of managing petabytes of data. That’s an important proof point as more organizations move in the direction of such massive data stores. (For more on the trend toward supersize databases, see “As Big Data Explodes, Are You Ready For Yottabytes?”)

3D Map Of The Galaxy
Even with the vast scope of this mission—mapping a billion stars over five years—Gaia is only scratching the surface of what’s out there. The Milky Way contains more than 100 billion stars.

Gaia stands for Global Astrometric Interferometer for Astrophysics, reflecting a design decision early in the project to use a single wave-measuring interferometer. As it turns out, ESA didn’t actually use that technique, but the name stuck.

The satellite will record the position, brightness, and color of every “celestial object” within view. In fact, it will measure them repeatedly. That way, astronomers will be able to calculate the distance, speed, and direction of motion of the objects and chart variations in their brightness.

You may need to get out a physics textbook to fully grasp other aspects of the mission. Gaia will allow for the testing of Albert Einstein’s Theory of Relativity, the space-time continuum, and gravitational waves, according to ESA.

The mission will result in a 3D map of the Milky Way that plots stars to a distance of 30,000 light years. An earlier star-mapping ESA mission called Hipparcos—launched in 1989 and concluded a few years later—recorded about 118,000 stars at distances of 300 light years.

Credit: NASA/JPL-Caltech/S. Stolovy (SSC/Caltech)

Photo credit: NASA/JPL-Caltech/S. Stolovy (SSC/Caltech)

Only uploaded — not written — by Louis Sheehan

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Louis Sheehan
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