Monday, July 24, 2006

Total Perspective

In his comment about Uranus, Pete refers to a book by Carl Sagan called Pale Blue Dot; apparently this was inspired by a picture taken from Voyager 1 looking back at the Earth from 4 billion miles away.

Officionados of the Hitch-Hiker's Guide to the Galaxy will remember the
Total Perspective Vortex which shows its victim the entire unimaginable infinity of the universe with a very tiny marker that says "You Are Here" which points to a microscopic dot on a microscopic dot.

Let's get things into perspective by considering the ratio 1:1,000,000:
- an average adult (1.7m) is about a million times bigger than a large bacterium (upto 2 microns);
- a 5-storey building (17m) is about a million times bigger than the width of the finest human hair (17 microns);
- the height of Big Ben or the length of a football pitch (about 100m) is a million times the thickness of paper (0.1mm);
- 2km is a million times wider than a grain of rice (2mm).

If I were as tall:
... as Mount Everest (8848m), then an adult would be as tall as the thickness of 3 pieces of paper;
... as the Earth is wide (12,756km), then Mount Everest would be smaller than a grain of rice;
... as the distance from the Earth to the Sun (150 million km), then the Earth would be a little bigger than the thickness of paper;
... as the distance from the Sun to the nearest star (4.22 light years), then the distance from the Earth to the Sun would be about the size of 3 large bacteria side by side;
... as the Galaxy is wide (100,000 light years), then the distance from the Sun to the nearest star would be less than the thickness of a piece of paper;
... as the Universe is wide (20 billion light years) then, the Galaxy would be half the thickness of the thinnest human hair.

[See
Orders of Magnitude and Physics Factbook]

No comments: