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First stars formed even later than previously thought

ESA’s Planck satellite has revealed that the first stars in the universe started forming later than previous observations of the Cosmic Microwave Background indicated. This new analysis also shows that these stars were the only sources needed to account for reionising atoms in the cosmos, having completed half of this process when the universe had reached an age of 700 million years.

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Fossilised rivers suggest warm, wet ancient Mars

Extensive systems of fossilised riverbeds have been discovered on an ancient region of the Martian surface on a northern plain called Arabia Terra, supporting the idea that the now cold and dry Red Planet had a warm and wet climate about 4 billion years ago, according to University College London-led research.

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Hubble’s fireball

In this NASA/ESA Hubble Space Telescope image we see the central Wolf-Rayet star known as Hen 2-427 — more commonly known as WR 124 — surrounded by the nebula M1-67. Both objects are found in the constellation of Sagitta some 15,000 light-years away. The hot clumps of gas ejected by the star into space are travelling at over 150,000 kilometres per hour.

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The curious case of Earth’s leaking atmosphere

Overall, about 1 kg of material is escaping our atmosphere every second. Every day, around 90 tonnes of material escapes from our planet’s upper atmosphere and streams out into space. Although missions such as ESA’s Cluster fleet have long been investigating this leakage, there are still many open questions. How and why is Earth losing its atmosphere?

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Saturn’s moon Enceladus and its paper-thin crust

Researchers have used data collected by the Cassini spacecraft to build a computer simulation of Saturn’s icy ocean moon Enceladus that includes the thickness of the ice crust. At its south poles, huge geysers of water jet into space. These come from the ocean depths and suggest that the ice there must be relatively thin for this to happen.

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The spider in the loop

This multicoloured swirl of yellow and blue shows a prominent ring of gas near the North Celestial Pole. The pole appears to be fixed in place, while the rest of the night sky slowly circles around it because of Earth’s rotation. This image comes courtesy of ESA’s Planck satellite, which spent years mapping the entire sky in exquisite detail between 2009 and 2013.