A Sense of Scale Page 12

Speed of light

Another way of looking at the scale of the Universe is to think about the speed of light, which is about 300,000 km/s. To get an idea of what this means, notice that with this speed you can go around the Earth at the equator seven and a half times in one second.
To reach the nearest star besides our Sun, you need to travel 4.5 years with this speed.

The light we see from the centre of the Milky Way galaxy, left its source about 25,000 years ago, that was when in the Upper Paleolithic the Venus of Dolní Věstonice figurine was created, one of the earliest known depictions of the human body. (Ref Wikipedia).

Venus of Dolní Věstonice.
Source Wikipedia.



The light we see from the Andromeda galaxy today, left 2.5 million years ago. That was when the Pleistocene began in the geological time scale, when on Earth the genus “Homo”  appeared, from which the modern humans have evolved much later.



This skull is 1.9 million years old, discovered in Kenya in 1973. Homo habilis is arguably the first species of the Homo genus to appear. Source Wikipedia




The furthest objects that we can see in deep space are at 14 billion light years.
That light was emitted 9 billion years before our Solar System formed.

A sense of scale of the Universe, is that reality or just a dream?