Enjoy our growing collection of featured articles in an informative reference series on all aspects of the natural world. From the origins of the universe and the evolution of life to plate tectonics and mechanisms of climate change, you will eventually find it here. Every chapter in this featured series focuses on a specific theme and consists of several subsequent articles that are best read in their original order.

Chapter 1: In the Beginning

Pillars of Creation - Hubble Space Telescope, NASA

Pillars of Creation – Hubble Space Telescope, NASA

Chapter 1.1: The Birth of the Universe – The universe came into existence approximately 13.7 billion years ago during the big bang. Find out more about how everything began!

Chapter 1.2: The Formation of the First Stars – The first stars formed from swirling gas clouds in empty space. How did this work?

Chapter 1.3: The Origin of the Elements – There are 92 naturally occurring elements, but only 5 of them were formed during the big bang. So where did the rest come from?

Chapter 1.4: The Dawn of the Solar System – Why do all planets orbit the Sun in the same direction and plane? Discover how this is related to the formation of the Solar System.

Chapter 1.5: Planetary Differentiation and the Development of the Earth-Moon System – Rocks from the Moon are very similar in composition to rocks from Earth’s mantle. Do you know why?

Chapter 1.6: Asteroids, Comets, Meteors and Meteorites – Asteroids, comets, meteors and meteorites represent different objects and phenomena in the Solar System, but what is actually the difference?

Chapter 2: Earth at a Glance

Blue Marble West, Earth – NASA/NOAA/Reto Stöckli

Chapter 2.1: Earth – A Tale of Spheres – If you were a space explorer visiting planet Earth for the first time, what would you see?