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Looking Up

Stand beneath the sky at any moment in human existence

300,000 BCE Tonight

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The shapes we made from stars

Move through time to see how familiar constellations slowly change shape

Orion

A familiar figure across continents, but the stars that make Orion are slowly drifting apart.

Big Dipper

Bear, wagon, plough, guide. One seven-star shape, many human meanings.

Pleiades

A rare case where the stars really are travelling together through space.

Crux

Four bright stars used to find south, and given very different meanings across cultures.

Scorpius

Scorpion in some traditions, fishhook in others. The curve itself is what endures.

Hyades

A V-shaped star group recognised across cultures and generations.

Castor & Pollux

Two bright stars seen as a pair across cultures, later imagined in European tradition as twins.

Cassiopeia

Five bright stars, one simple zigzag, recognised and renamed across cultures.

Leo

The Sickle is the memorable shape; the lion is one of many stories laid over the same stars.

Sirius

The brightest star in the night sky became a marker of seasons and calendars.

Cygnus

A cross of stars through the Milky Way, later imagined in European tradition as a swan.

Corona Borealis

A simple arc of stars that different cultures turned into crowns, circles and other forms.

How the stars rearrange themselves

The constellations we recognise tonight have not always looked this way.

Every star is moving. Over a human lifetime the change is almost impossible to see, but across thousands of years the familiar patterns begin to distort. The Big Dipper changes shape. Orion slowly pulls apart. Given enough time, the constellations we know disappear altogether.

That movement is called proper motion: the measured drift of a star across the sky. Move those measurements backwards through time and the apparently fixed night sky begins to move.

The same sky does not stay the same.

About the data

The stars in this exhibit come from the HYG star catalogue, which combines data from major astronomical catalogues including measurements from ESA’s Hipparcos mission.

Each star is represented by its position and measured velocity. Those values are propagated backwards from the J2000 reference epoch to reconstruct how the relative positions of the stars change through time.

The main sky view also accounts for the long-term precession of Earth’s axis and the observer’s position on Earth, allowing the reconstructed stars to be placed against the local horizon.

At very long timescales, uncertainty increases. The farther the reconstruction moves from the present, the less precisely individual stellar positions can be known. The view at 300,000 BCE should therefore be read as a reconstruction of the ancient sky, not an exact snapshot of it.

Planet positions are shown only between 4,000 BCE and 8,000 CE, where the exhibit uses its higher-accuracy planetary model.

Sources: Hipparcos and Tycho Catalogues (ESA 1997), HYG v3.8 catalogue maintained by David Nash, European Space Agency Technical Report (1997), Urban & Seidelmann, Explanatory Supplement to the Astronomical Almanac (3rd ed., 2013), Meeus, Astronomical Algorithms (2nd ed., 1998)

Credits: Concept, design and code: Lee McGorie

Published August 2026