Explaining one thing a week in a sketch
Solar system planets: how big is the solar system?
It’s pretty hard to get to grips with the scale of the solar system. It's really, really, really big.
To help process the vast distances within our system, astronomers use Astronomical Units where 1 AU is the distance of Earth from the Sun. If you see Venus in the night sky, our closest neighbour just 0.7 AU from the sun, it looks impossibly far away. But the further out you go, the more the distances multiply.
Earth and Venus are practically on top of each other compared to Uranus and Neptune. Neptune is a full 30 times the distance between Earth and the Sun.
Now think about the fact that our little solar system is over 250,000 AUs from our nearest star, which is, in turn, just one of many tucked away in a small corner of the Milky Way, which is only one of many galaxies that make up the known universe.
It might be time to sit down.
James O'Donoghue has made some brilliant videos about the solar system that explain this and more.
This sketch, and plenty more in the Starry-eyed Surprises section, features in my book Big Ideas Little Pictures
The original sketch of solar system sizes is on a paper background.
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