How this European spacecraft is mapping the Milky Way galaxy
European Space Agency's (ESA) Gaia space telescope is instrumental to scientific research as it creates a 3D map of the Milky Way. The spacecraft measures the positions and trajectories of roughly two billion stars so that astronomers can witness the changing nature of the galaxy over billions of years. This astronomical mission has produced the most scientific papers since its launch.
Why does this story matter?
This year, researchers working with Gaia released the third set of data it collected over its lifetime, and it has provided important information about starquakes and the composition of stars. The German Aerospace Centre claims that its final catalog will comprise over a petabyte (1 million gigabyte) of data. The Hubble and James Webb might be more popular, but Gaia's contribution cannot be ignored.
A brief look at the Gaia space telescope
The Gaia was launched in December 2013 and will be operational until 2025. The 2.3-meter wide satellite is linked to a circular sunshield and fitted with two telescopes as well as a 1-billion-pixel camera. There are also red and blue photometers for measuring the brightness/color of the stars as well as a radial velocity spectrometer. Each day, Gaia sends 20-100GB of data to Earth.
How does the Gaia work?
The Gaia sits in a position called Lagrange Point 2, which is around 1.5 million kilometers away from Earth. It orbits the sun in sync with our planet. The spacecraft collects data about a star's composition using a technique called spectroscopy, which breaks down light into different wavelengths. Hence, by looking at the light a star gives off, we can find out its composition.
A star's metallicity helps in ascertaining its age
Gaia has allowed researchers to create a color-coded map of the stars in our galaxy, and this aids in finding out whether the stars are new or old. The newer ones have a higher percentage of heavy elements and the phenomenon is called a star's metallicity. By seeing which regions have stars with higher/lower metallicity, scientists can map out Milky Way's evolution over time.
