100,000,000,000

100,000,000,000

This is the number of stars that are believed to exist within our Milky Way Galaxy. In addition to the new James Webb Space Telescope, another smaller space telescope has been quietly mapping our galaxy at the L2 Legrand orbit since 2013, the Gaia Space Telescope.

While much smaller and more cantered on visible light (although with a small overlap into Infra Red and Ultra Violet), it's aim was to record 1 billion stars, and as much detail about them and their movement around the galaxy as is possible.

Gaia surpassed it's original 5 year mission, and the 1 billion stars too, now at over 2 billion stars, but just 2 % of our galaxies total star number.

It's expected that Gaia could last a few more years, maybe to aim towards the 5 billion mark, but still just 5 % of all the stars in our galaxy.

Many stars simply cannot be seen, the dust and gas between us and the rest of the galaxy renders most stars simply impossible to view, and of course, a good 1/3rd of our galaxy is behind the centre of our galaxy (see zone of avoidance below).

While the James Webb Telescope isn't going to be charting space like Gaia is, it is going to be able to see stars simply invisible to Gaia.

Firstly, the JWST is MUCH larger than Gaia that only has a primary mirror of around 1.5m x 0.5m , compared to 6.5 meters. This gives the new JWST significantly more space to collect photons and assemble an image.

Secondly, JWST is focused on the IR part of the spectrum, one that allows astronomers to see through the dust and gas, showing us stars Gaia could only dream of mapping.

JWST isn't on catalogue duty, but it is going to see things we at this moment, don't even realise exist, and with 98% of the stars still unmapped, despite Gaia's best attempts, there's a lot more to find out, and that's just the stars in our own galaxy, never mind the trillions of galaxies out beyond our own.