The Little Book of Big History

WHERE DOES THE ENERGY COME FROM?

Our Sun lies on one of the spiral arms of our galaxy, about 30,000 light years from the centre. The nearest star to the Sun is Proxima Centauri, just 4.24 light years away.

chink in this theory came in the 1920s when the American astronomer Edwin Hubble observed that the further away a galaxy is from us, the faster it is receding. He concluded that the universe is expanding, and that this expansion started in a single great explosion, which became known as ‘the Big Bang’.

next big leap came 1.8 billion years ago, when larger, more complex cells appeared. These so-called eukaryotic cells contain the DNA within a central structure, the nucleus. There are also a number of other specialist structures with particular functions. These are called organelles. The fact that some of them have their own

‘The wonder is, not that the field of the stars is so vast, but that man has measured it.’
Anatole France, The Garden of Epicurus (1894)

the part of it we can observe is 93 billion light years in diameter

Within recorded history, the largest volcanic eruption was that of Mount Tambora in Indonesia in 1815. It blasted so much ash into the Earth’s atmosphere that for many months much of the Sun’s light was blocked out, and 1816 became known as ‘the year without a summer’.

Nor could they explain the great variety of species that now populate the world.

the Milky Way, contains 100–400 billion stars and has a diameter of around 100,000 light years

The size of the universe is a subject of speculation, but the part of it we can observe is 93 billion light years in diameter.