Planetary Picture of the Day - Week of April 13, 2026

Monday, 13 April 2026

Lava Flow on Réunion Island

This Copernicus Sentinel-2 image captures an active lava flow on the Piton de la Fournaise volcano on Réunion Island.

Located in the western Indian Ocean, the island of Réunion is a French overseas department about 680 km east of Madagascar. Réunion's volcanic origins make its landscape particularly rugged in places and lushly vegetated in others. Cultivated land and cities, visible as grey-white clusters, are concentrated on the coastal lowlands. The capital and largest city is Saint-Denis, on the northern coast, mostly covered by clouds in the image.

The center of the island shelters three vast cirques, or calderas, created by huge collapses. Together they form the dormant shield volcano and the island's highest peak, Piton des Neiges (3069 m), which peeps out in brown from beneath the clouds near the center of the image.

Although Réunion hosts multiple volcanoes, only one is currently active: the Piton de la Fournaise shield volcano, one of the most active on Earth, which dominates the southeastern part of the island. This image, from 21 March 2026, shows a lava flow on its western flank, following an eruption that began in mid-February.

Wednesday, 15 April 2026

Earthset

The Artemis II crew captured this view of Earth setting on April 6, 2026. As the astronauts flew over the Moon’s far side, the crew photographed and described terrain features, including impact craters, ancient lava flows, and surface cracks and ridges formed as the Moon slowly evolved. They also noted differences in color, brightness, and texture, which provide clues that help scientists understand the composition and history of the lunar surface.

The image is reminiscent of the iconic Earthrise image taken by astronaut Bill Anders 58 years earlier as the Apollo 8 crew flew around the Moon. The Apollo 8 mission was the first crewed spacecraft to circumnavigate the Moon.

Friday, 17 April 2026

The Sun’s Inner Corona

The Sun’s inner corona, the hottest part of our star's atmosphere, appears faint yellow in this image taken by the ASPIICS coronagraph aboard Proba-3. The image combines data from Proba-3’s ASPIICS coronagraph (inner solar corona in yellow) and from the Atmospheric Imaging Assembly (AIA) aboard NASA’s Solar Dynamics Observatory (solar disc in dark orange).

Seen at the 11 o'clock and 5 o'clock points are structures made of relatively cold plasma, known as prominences, although they are still around 10,000 degrees Celsius. Prominences can expand outwards from the Sun and ‘erupt’, breaking up and sending plasma in different directions. The eruptions were captured in the spectral line emitted by helium atoms, showing the solar atmosphere as a human eye would see it during a total eclipse through a yellow ASPIICS filter. The AIA image shows emission from another helium spectral line.

The remaining faint yellow glow of the corona is a result of the scattering of visible light from the Sun's surface on coronal electrons.