Gaia - ESA's mission to map the Milky Way

Gaia - ESA's mission to map the Milky Way

Gaia mapping the stars of the Milky Way node full image.jpg

In 129 BC the ancient Greek astronomer Hipparchus founded astrometry. He measured the position of 1,000 stars in the night sky to an accuracy of about 1 degree using nothing other than his naked eye and the simple geometry mathematics of the time. Fast forward a little over 2,000 years and meet Gaia the most sophisticated astrometry machine to date. 

Gaia's Main Mission Objective

Gaia is the European Space Agency's mission to create the most detailed 3D map of the Milky Way ever created. It will map the position of 1,000 million stars and measure their velocity. This will hopefully not onyl create a detailed map of our Milky Way galaxy but also allow astronomers to trace back where the stars came from and look back into the history of the Milky Way.

Why is it interesting to see where stars have come from? The answer to this is that we can determine if the stars originated in the Milky Way and which stellar nurseries they may have come from. It will also shed light on how many stars came from other satellite galaxies.

What Else Can It Do?

As Gaia not only measures the position and motion of the stars but also the colour and brightness it is expected to have many secondary mission objectives too. These include being able to detect the wobble of stars and therefore, find hopefully tens of thousands of new exoplanets. It should be able to spot many new asteroids and determine if they pose a threat to Earth or not. Crucially it will be able to spot asteroids near to the Sun which is a blind spot to Earth based telescopes.

It is also hope to detect comet showers, brown dwarf stars, supernovae in distant galaxies and provide more information on gravitational waves which were predicted to be left over from the Big Bang by Einstein but have yet to be detected.

Gaia looks like and exciting spaceship to watch. But it is incredible to think that this spacecraft will map 1 billion (US numbers) stars and our Milky Way is estimated to contain 300 billion stars. So we still have a long way to go before we will have a detailed map of the whole Milky Way.

Find more information on Gaia from the ESA.

First image credit: ESA/ATG medialab; background: ESO/S. Brunier

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