Artist's impression of Gaia
Credit: ESA/Space in Images

Gaia is a European Space Agency (ESA) spacecraft, designed to measure the positions and distances of stars, a process called astrometry. The mission aims to create the largest and most precise 3D space catalogue ever made, with over 1 billion astronomical objects including planets, comets, asteroids, and quasars. This represents 1% of the Milky Way.

Some facts about the telescope:

  • Mass: 2,029 kg
  • Mirror dimensions: 1.45 x 0.5 m
  • Launch date: 19th December 2013

The spacecraft will monitor each of its targets 70 times over a 5 year period. Launched in 2013, Gaia is currently 3 years into its 5 year mission. This may be extended, since the spacecraft has enough power to operate for 9 years, and its detectors are still in excellent condition.

Gaia is expected to detect thousands of Jupiter-sized exoplanets, 500,00 quasars, and thousands of asteroids and comets within the solar system. The 3D catalogue Gaia creates will map the Milky Way, giving scientists information about the origin and evolution of our galaxy.

A few of Gaia's scientific results:

  • on 12th September 2014, Gaia discovered the first supernova in another galaxy
  • on 3rd July 2015, Gaia released a map of the star density in the Milky Way, using the data it had recorded during its operation (pictured below)
  • the light from more than 3000 variable stars has been monitored and analysed

It is expected that the completed Gaia catalogue will be published in 2022, three years after the end of its planned 5 year mission.

Gaia map of the star density of the Milky Way
Gaia map of the star density of the Milky Way, showing the small and large Magellanic Clouds
Credit: ESA/Gaia