obelisk 2026
Thank you, Teddy. Today I will be explaining to you what exoplanets can teach us about the formation and diversity of planetary systems. There are many types of exoplanets, but before we go over them I want to tell you about the most common theory of exoplanet formation: the Nebular Hypothesis. It holds that planets are formed like snowballs, from a cloud called a nebula, that have been rolled and rolled until they get bigger and bigger. First, dust clumps become pebbles, then pebbles become larger rocks that merge together to become big enough to become planets or exoplanets. Thanks to gas, particles of solid material stick together. Some break apart, but the important ones are the ones that hold on. This process takes millions of years! These steps are the building blocks of worlds. Furthermore, scientists have used telescopes like the Hubble to observe preplanetary discs forming around other stars to validate this hypothesis. See those triangles? They are nebulae and all those dots are exoplanets. As you can see they match up. This is how we know exoplanets must come from nebulae. The variety of exoplanets we have detected gives us a better understanding of their conditions and how their solar system and ours were formed.
Additionally, there are many types of exoplanets. There are terrestrial planets like the Earth, composed of rock, silicate, water or carbon. There are also Super-Earths, which are larger than Earth but are much more common. Gas Giants are big planets made of gas, like Jupiter, and Ice Giants made of ice, like Neptune. Our solar system has all of these, but some exoplanet systems have only one.
Finally on February 22, 2017, NASA announced the discovery of the most Earth-sized planets found in the habitable zone of a single star, called TRAPIST-1. This system includes seven rocky planets all of which have the
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