Mission Non-Trivial: Mapping the Milky Way


The Global Astrometric Interferometer for Astrophysics, Gaia is the newest space telescope, soon to be launched by the European Space Agency.

In Greek mythology, Gaia was the creator and giver of birth to the Earth and all the Universe. An apt name, then, for the craft whose mission is to map our home galaxy to unprecedented levels of precision. It will pinpoint approximately a billion stars in our galaxy, precisely measuring their distances from us by tracking the apparent movement of the nearby star with relation to distant background stars.

The accuracy with which Gaia will place stars is comparable to measuring the diameter of a human hair at a distance of 1000 km. It is able to do this because of its array of  CCDs (charge coupling devices). CCDs turn the light reaching them into electrical signals, which can then be transmitted back to a computer. These are the same tools that your digital camera or smartphone uses. The difference is that there are a lot more of them, in fact there are over a 100 times as many.

This isn’t all; as well as measuring details of its target stars Gaia will log anything that crosses its field of view from comets to asteroids and supernovae. Scientists hope that this will generate a whole host of new discoveries.

When astronomers put forward their proposal for the mission around 20 years ago, they thought they were requesting the impossible. It may not be Mission Impossible, but there’s still a way to go. Keep posted on Gaia’s activities on the blog from the European Space Agency: http://blogs.esa.int/gaia/.


Physics student and regular freelance science communicator, shooting for the stars. I'm your Science Editor and with the help of a team of talented writers, strive to bring you the most interesting and relevant science stories.

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