Our Star Is Born

Programme Outline

The birth of the Sun and planets, triggered by the death of a giant star, is presented. In a journey to the Sun's core, the mechanism of its energy production by nuclear fusion is revealed. We follow the path of this energy, up from the core to the solar surface and across space to Earth. The Sun is presented as the ultimate source of energy for our planet.

Layer by layer, the Sun's structure is revealed: first the yellow photosphere with its sunspots, then the fiery red chromosphere with its prominences, and finally the corona, the Sun's outer atmosphere at a temperature of a million degrees K. The influence of the Sun's magnetic field is shown to be very important. Much of the information and many of the pictures featured were obtained by the spacecraft SOHO, the Solar Heliospheric Observatory.

Lastly the death of the Sun is illustrated. Initially it becomes a bloated red giant engulfing Mercury, Venus and Earth, then puffing off its outer layers to reveal the white-hot core which collapses to a white dwarf, finally cooling to become a dark relic of a star.

00.10 - 01.35 Introduction

• Our view of the Sun now and in the past.
• The Sun as a star - a basic description of its functions.
• The mechanics of the Sun's birth and the formation of the planets.
• A brief tour of the Solar System.

01.35 - 03.05 Energy from the Sun

• The Sun as the ultimate source of most of the Earth's energy resources, particularly fossil fuels.
• Internal composition of the Sun. How mass is transformed into energy in the Sun's core and how this energy travels to the Earth.
• How the Sun's emission spectrum reveals its chemical composition.

03.05 - 05.13 The solar surface, or photosphere

• The temperature and overall physical appearance of the photosphere.
• Sunspots and the Sun's magnetic field. The 11-year solar cycle and magnetic reversals.
• Differential rotation of the Sun.

05.13 - 06.19 The chromosphere, prominences and flares

• The overall physical appearance of the chromosphere.
• Prominences - arcs of gas looping around magnetic field lines.
• Violent flares blasting ripples across the face of the Sun.

06.19 - 08.00 The corona and SOHO

• Description of the corona, the Sun's outer atmosphere, visible during a total eclipse.
• Great ejections from the corona. Reasons for the corona's varying appearance and activity. Observations by the spacecraft SOHO.
• The solar wind, a stream of electrified particles continuously emitted by the Sun.
• The mystery of why the corona is so hot.

08.00 - 08.52 Secrets of the Sun

• Investigations of the Sun by SOHO. SOHO's revelations of the Sun's internal behaviour.

08.52 - 09.50 Death of the Sun

• Explanation of why the Sun will one day expire. The various stages of its death and their effect on the inner planets.