A solar eclipse is caused by the movement of the Moon around Earth. Despite their much different sizes, due to their separation, the Moon appears to be about the same size as the significantly larger Sun in the sky. Occasionally, the Moon passes in front of the Sun, blocking its light, so that part of the Earth’s surface is in the Moon’s shadow. The line-up is not always perfect, and so not every eclipse is a total solar eclipse.
On 25 October only part of the Sun’s light was blocked by the Moon, creating what is known as a partial eclipse. It was visible from most of Europe, North-Africa, the middle East and parts of Asia, with the Moon blocking 82% of the sunlight near the North Pole. In Europe up to 40% of the sunlight was obscured during the event.
This partial eclipse was observed by ESA’s Proba-2 mission from its unique vantage point in space. Its SWAP instrument studies the Sun in the extreme ultraviolet (EUV) light where it focuses on the solar corona – the Sun’s hot turbulent atmosphere – at temperatures of about a million degrees. The corona is seen in the background of this video.
For us on Earth, the Moon passes only once in front of the Sun during a solar eclipse. Since Proba-2 orbits the Earth in about 100 minutes, it was able to observe this eclipse not once but twice. Additionally, the Moon was first observed while traversing the field of view in the upper right corner, but not blocking any solar light. The first observation of the eclipse around 10:30 UTC (12:30 CEST) was cut short as Proba-2 experienced an occultation. Such an occultation occurs when Proba-2 flies through the Earth’s atmosphere and the SWAP instrument is not active. The second partial eclipse was captured around 12:25 UTC (14:25 CEST). This movie shows both the eclipses.
ESA’s Sun-watching spacecraft monitor the Sun’s behaviour to better understand the influence of space weather on our home planet. The ESA-led Solar Orbiter mission, in partnership with NASA, is orbiting the Sun from closer than ever before and will provide the first high resolution images of the Sun’s poles. Meanwhile ESA Vigil will be the first mission to keep a constant eye on brewing space weather events, to better protect vital infrastructure on Earth and in orbit.