THE SCALE OF SPACE

The scale of the Universe is so vast that we cannot appreciate its size without making leaps of scale. In this series of pictures, each stage represents a microscopic speck of the image to its right. When dealing with the vast distances in space, kilometres aren't big enough. Instead, astronomers use the speed of light as a yardstick. Light is so fast it can travel around Earth 7.5 times in a second. One light year is the distance light travels in a year: nearly 10 trillion km (6 trillion miles).

Earth and Moon

 

Earth is 12.756 km (7.926 miles) wide Our nearest neighbour in space - the Moon orbits Earth at a distance of 384.400 km (238.855 miles). If Earth were the size of a football, the Moon would be the size of a melon about 21 metres (69 ft) away.

Solar System

The Sun's family of eight planets occupy region of space 9 billion km (5.6 billion miles) wide If Earth were a football, it would take five days to walk across this part of the Solar System. The nearest star would be a S8-year walk away.

Stellar neighbourhood

The nearest star to the Sun is Proxima Centauri, which is just over four light years away. There are around 2.000 stars within 50 light years of the Sun. These make up our stellar neighbourhood, which is a tiny fraction of the Milky Way galaxy.

Milky Way galaxy

The Milky Way is a vast cloud of 200 billion stars. Its shape resembles a pair of fried eggs held back to back, with a central bulge surrounded by a flat disk. It measures 100,000 light years across the disk and

2,000 light years deep through the bulge.

Local Group of galaxies

The Milky Way is just one of perhaps seven trillion galaxies in the observable Universe, Galaxies exist in groups called clusters, held together by gravity. The Milky Way is part of a cluster known as the Local Group which is about 10 million light years wideSolar System

The Sun's family of eight planets occupy region of space 9 billion km (5.6 billion miles) wide If Earth were a football, it would take five days to walk across this part of the Solar System. The nearest star would be a S8-year walk away.

Supercluster

Clusters of galaxies exist in even larger groupings called superclusters. We live in the Virgo Supercluster, which is one of millions of superclusters in the known Universe. Between these are immense empty areas called cosmic voids.

Universe

Superclusters are thought to form a vast web of filaments riddled with enormous voids containing no galaxies. The true size of the Universe is a mystery, and only a fraction of it is visible to us. The Universe may even be infinite in size.

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