Building blocks

## Data sheet

Here are some data which you might find useful.

### Paper sizes

• A4 paper measures $\quantity{298}{mm}$ by $\quantity{210}{mm}$.

• A3 is double the area of A4 — $\quantity{298}{mm}$ by $\quantity{420}{mm}$.

• To go from A4 to A3 and from A3 to A2 you double the shorter dimension each time. The sequence continues up to A0.

• American Letter size paper is $\quantity{8.5}{in.}$ by $\quantity{11}{in.}$.

### On Earth

• The Shard in London is $\quantity{309.6}{m}$ high. Its viewing gallery is approximately $\quantity{244}{m}$ above ground level.

• One of the tallest buildings on Earth is the Burj Khalifa in Dubai, at $\quantity{829.8}{m}$.

• The highest mountain is Mount Everest, at $\quantity{8\,848}{m}$.

### In astronomy

• The mean distance from the Earth to the moon is $\quantity{378\,000}{km}$ (from the NASA Moon Fact Sheet).

• The mean distance from the Earth to the sun is $\quantity{149\,600\,000}{km}$ (from NASA Solar System Exploration).

• After the Sun, the nearest bright star is Alpha Centauri, at a distance of about $\quantity{4.4}{light\,years}$ from Earth.

One light year is the distance that light can travel in a year. Light travels at a speed of about $\quantity{300\,000}{km\,s^{-1}}$.

• Andromeda, the closest major galaxy to our own, is approximately $\quantity{2.5}{Mly}$ from Earth.

$\quantity{1}{Mly}$ (megalight year) is $\quantity{10^6}{light\,years}$.

• The edge of the known Universe is approximately $13.8$ billion light years away.