Events · Solar System scale
Eclipse
When one celestial body moves into the shadow of another, or passes directly between an observer and a light source. The two main types are solar eclipses (Moon blocks the Sun) and lunar eclipses (Earth's shadow falls on the Moon).
Upcoming event
The 2027 total solar eclipse on 2 August crosses Spain, North Africa and the Middle East — totality lasts up to 6 min 23 sec, one of the longest of the century.
Source: NASA Eclipse Web Site
Solar eclipses and totality
The geometry of a total solar eclipse is a remarkable cosmic coincidence: the Sun's diameter is about 400 times larger than the Moon's, and the Sun is almost exactly 400 times farther away. The result is that the Moon appears almost the same angular size as the Sun (about 0.5°), allowing it to cover the solar disc almost exactly during totality.
During the brief period of totality — which can last up to 7 minutes 31 seconds in exceptional cases — the solar corona becomes visible as a white halo, temperature drops noticeably, and bright planets and stars appear. The sky reaches a twilight blue rather than true night. This experience is fundamentally different from a partial eclipse: even 99% coverage leaves the sky too bright to see the corona.
For safety: never look at a partial solar eclipse without certified solar filter glasses (ISO 12312-2). Only during full totality, when the photosphere is completely blocked, is it safe to look with the naked eye. See our 2027 eclipse guide and the Sun guide for observing safety.
Frequently asked questions
- In a solar eclipse, the Moon passes between Earth and the Sun, casting a shadow on Earth's surface. It can only happen at new moon. In a lunar eclipse, Earth passes between the Sun and the Moon, casting Earth's shadow onto the Moon. It can only happen at full moon. Solar eclipses are rarer to experience from any given location because the Moon's shadow on Earth is only a few hundred kilometres wide — you must be within the narrow path of totality. Lunar eclipses are visible from the entire night-time half of Earth simultaneously. See our 2027 total solar eclipse event page for the upcoming opportunity.
- There are four types: Total — the Moon completely covers the Sun's disc; the corona becomes visible and the sky darkens to near-night. This requires being in the Moon's umbra (darkest central shadow). Annular — the Moon is near apogee (farthest from Earth) and appears slightly smaller than the Sun; it covers the centre but leaves a bright ring ("annulus") of sunlight. Partial — only part of the Sun is covered; the observer is in the penumbra (outer shadow). Hybrid — the eclipse transitions between annular and total along its path due to Earth's curvature. NASA's eclipse catalogue lists every eclipse from 2000 BC to 3000 AD.
- When the Moon passes through Earth's umbra (full shadow), it doesn't go completely dark — it turns a deep red, copper, or orange colour. This is because Earth's atmosphere refracts (bends) sunlight around the edge of the planet and into the shadow. The atmosphere filters out the shorter blue wavelengths (scattered away, creating blue skies on Earth) and allows longer red wavelengths to bend through. The refracted red light then illuminates the Moon. The exact colour and brightness depend on the state of Earth's atmosphere — after major volcanic eruptions, the Moon can appear very dark. This phenomenon gives total lunar eclipses the name "Blood Moon".
- Total solar eclipses occur globally roughly every 18 months on average, but they follow narrow paths — any given location on Earth experiences totality only once every ~375 years on average. The next major total solar eclipse is on 2 August 2027, with a path crossing Spain, North Africa, Egypt, Saudi Arabia, and Yemen. Totality lasts up to 6 minutes 23 seconds — one of the longest of the 21st century. Before that, a total lunar eclipse is visible from much of Earth on 7 March 2026. Check our 2027 solar eclipse event page for full details.
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