How long will the Sun continue to shine? - Week 27

Aug 26, 2026

Uploaded by Xiajie

A shining, well-functioning Sun is essential for survival on Earth. Formed nearly five billion years ago, it keeps shining due to an enormous hydrogen supply, yet solar radiation intensifies over time, making conditions progressively lethal. After roughly two to three billion years, oceans evaporate and life becomes unsustainable. The document explains subsequent evolutionary stages: expansion into a red giant that engulfs inner planets, transformation through helium fusion into a white dwarf, then gradual cooling toward a black dwarf.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages2

Reading Time5 min

AccessFree to download

The Sun’s role in Earth’s survival

Hydrogen supply and future radiation

The Sun’s life cycle and red giant phase

From red giant to white dwarf

News Archive 2009 How long will the Sun continue to shine? Week 27 A shining and 'well functioning' Sun is critical for our survival on Earth. The Sun was formed almost five billion years ago. At that time, a gas and dust cloud became so condensed due to its own gravity that hydrogen nuclei began to merge with each other and release huge amounts of energy in a process known as nuclear fusion. Fortunately, the Sun's supply of hydrogen is so great that it will continue to shine for another five billion years. However, the intensity of the solar radiation will increase in the future and this will be fatal for life on Earth. As early as two to three billion years from now, the oceans will evaporate and it will become impossible to live on Earth. The Sun's life cycle On approximately its ten-billionth birthday – that is, in around five billion years from now – the hydrogen supply in the core of the Sun will be exhausted and the generation of energy will shift to the outer layers. As a result of this change, the Sun will expand and become a red-coloured giant star that engulfs the planets closest to it – Mercury and Venus. As a 'Red Giant', our Sun will lose a considerable amount of mass – by expanding sharply, the gravitational force at its surface will decrease and, unlike now, a lot of solar matter will pour into space. As its mass reduces, the planets will not be attracted to the Sun as strongly as at present and their orbits around the Sun will shift further outwards. The Earth will gradually move to where the planet Mars orbits today. From Red Giant to White Dwarf This does not by any means spell the end of the Sun's dance of death – helium will become concentrated in the centre of the giant red Sun and will begin to 'melt' – forming heavier elements by means of nuclear fusion. This will cause the Sun to contract again as it slightly collapses inward. Near the end of the red giant stage, the helium-fusion zone will also shift to the outer layers of the Sun and the Sun will inflate again. At this point, the fusion of helium will cease, leaving the Sun without a source of energy. Once the outward force caused by radiation pressure is absent, the solar mass will collapse inward. During this collapse, the Sun’s surface will heat up again – so much so that it will emit a significant amount of ultraviolet radiation. This will heat the matter that was previously ejected into space and cause it to glow – a 'planetary nebula' will be formed. At the nebula's centre, the Sun will remain as a glowing 'white dwarf' star. The White Dwarf will be about the size of Earth, but its matter will be so densely packed together that a piece the size of a sugar cube will weigh a ton. Over the course of several more billions of years, the White Dwarf will slowly cool down – becoming a 'black dwarf' – and then our Sun will finally have disappeared. Related Contacts Dr. Manfred Gaida German Aerospace Center Space Administration, Space Science Tel: +49 228 447-417 Fax: +49 228 447-745 E-Mail: [Manfred.Gaida@dlr.de](Manfred.Gaida@dlr.de) How long will the Sun continue to shine? 1 / 2 Contact details for image and video enquiries as well as information regarding DLR's terms of use can be found on the DLR portal imprint.

FAQs

Why is the Sun’s condition critical for life on Earth?

A stable, well-functioning Sun provides the conditions required for survival. Increasing solar radiation intensity in the future will become fatal for life on Earth.

What happens to the Sun when its core hydrogen is exhausted?

Energy generation shifts to outer layers, causing the Sun to expand into a red-coloured giant that engulfs Mercury and Venus.

How does the Sun change from the red giant stage to a white dwarf?

Helium becomes concentrated and begins fusion into heavier elements. The Sun contracts, forms a planetary nebula, and leaves a glowing white dwarf at the center.

What is the end state of the Sun described in the document?

The white dwarf slowly cools over billions of years, ultimately becoming a black dwarf and disappearing.

Aug 26, 2026

Uploaded by Xiajie