OUR COSMIC HOME

Daisy Dobrijevic finds out more about our place in space, uncovering the secrets of the Milky Way, from its swirling arms to the monster lurking at its heart.

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Imagine trying to draw a map of your entire neighbourhood - every street, every house, every lamppost. Now, imagine that neighbourhood is the Milky Way, our home galaxy. It is 100,000 light years wide (a light year is the distance light travels in one Earth year) and contains billions of stars. For the last 10 years, a European Space Agency (ESA) space telescope called Gaia has been busy creating the most detailed map of the Milky Way ever.

Since 2013, Gaia has been carefully putting together a three-dimensional map of our galaxy. Working with incredible precision and taking more than three trillion observations, the spacecraft has discovered the positions, movements and brightness of nearly two billion stars. Thanks to this amazing, high-tech machine, we know more about our cosmic neighbourhood than ever before.

However, Gaia's fuel reserves are now running low and the spacecraft is getting ready for retirement. So what did it discover? And what's next for exploring our cosmic home? Let's blast off on a journey through the Milky Way and find out.

Our cosmic neighbourhood

The Milky Way is a "barred spiral galaxy". It's 13.6 billion years old, and its long curving spiral arms wrap around a bright centre containing a supermassive black hole called Sagittarius A*. A black hole is a place in space where gravity pulls so strongly that not even light can escape. This greedy beast is as massive as four million Suns. Travel out from Sagittarius A* - about 150,000 trillion miles (or 26,000 light years) - and you'll find a rather sleepy suburb called the Orion Arm. Here you'll find our solar system, planet Earth and of course, us. This is home.

Inside looking out