Heliocentric Model of the Solar System
Earth and Space

Early astronomical observations

Teaching Guidance for 14-16 PRACTICAL PHYISCS

The observations of early astronomers enabled them to determine the following:

  • There is an unchanging pattern of stars, revolving daily round an axis through the Pole Star.
  • Sun, Moon and planets share that daily motion, except they drift slowly backward through the star pattern.
  • The paths of the Sun, Moon and planets fall in a narrow band of the star pattern called the Zodiac.
  • ‘Freezing out’ the daily rotation, we find the Sun travels round the ecliptic, the central line of the Zodiac, in a year.
  • The Moon travels round an orbit in the Zodiac, tilted at some 5° to the ecliptic, in a month.
  • Mars, Jupiter, and Saturn travel round orbits in the Zodiac, making reverse loops, one for each Earth year, as they do so.
  • Mercury and Venus are only visible shortly after sunset and before sunrise – they remain close to the Sun.
  • Jupiter completes an orbit of the Sun in 12 years, Saturn in 30 years, Venus in a fraction of an Earth year
Limit Less Campaign

Support our manifesto for change

The IOP wants to support young people to fulfil their potential by doing physics. Please sign the manifesto today so that we can show our politicians there is widespread support for improving equity and inclusion across the education sector.

Sign today