Have you ever gone on a holiday to another country, or maybe even another continent? Earth is a huge place, isnβt it? Or is itβ¦?
Hereβs what the earth looks like from the ISS:
You canβt see borders from 400 km up!
From the moon, the closest celestial body to earth, all you see is a ball of blue and some green.
From Mars, itβs just a dot.
What about the farthest image ever taken from earth?
Taken by Voyager 1, theΒ βPale Blue Dotβ as this picture is called, shows our little planet from a distance of 6 billion kilometers. Earthβs size in this picture is less than a pixel!
Voyager 1 has now left the solar system, so it must be really far now, right? Well, itβs currently (2016) at a distance of 20.5 billion, or 20,500,000,000, kilometers. But how does that compare to the size of our galaxy, the Milky Way?
Itβs about 1,000,000,000,000,000,000 kilometers across. That means that Voyager traveled 1/50,000,000 of the diameter of our galaxy in 39 years. It wonβt come close to another star for another 40,000 years.
The Milky Way is just one of many galaxies like these:
Yeah, earth is a big place. Itβs just that space is even bigger. A lot bigger.