News by Subject Space & Planetary

While attention has been focused on the Perseverance rover that landed on Mars last month, its predecessor Curiosity continues to explore the base of Mount Sharp on the red planet and is still making discoveries.

Every year, our planet encounters dust from comets and asteroids. These interplanetary dust particles pass through our atmosphere and give rise to shooting stars. Some of them reach the ground in the form of micrometeorites. An international program conducted for nearly 20 has determined that 5,200 tons per year of these micrometeorites reach the ground.

Astronomers at Western University have discovered the most rapidly rotating brown dwarfs known. They found three brown dwarfs that each complete a full rotation roughly once every hour. That rate is so extreme that if these "failed stars" rotated any faster, they could come close to tearing themselves apart. Identified by NASA's Spitzer Space Telescope, the brown dwarfs were then studied by ground-based telescopes including Gemini North, which confirmed their surprisingly speedy rotation.

The 15-million-year-old Nördlinger Ries is an asteroid impact crater filled with lake sediments. A research team led by the Göttingen University has now discovered a volcanic ash layer in the crater. In addition, they show that the ground under the crater is sinking in the long-term, which provides important insights about craters on Mars, such as those currently being explored by the NASA Curiosity and Perseverance Rovers. Results were in the Journal of Geophysical Research Planets.

The Perseverance rover has just landed on Mars. Meanwhile, its precursor Curiosity continues to explore the base of Mount Sharp at the centre of the Gale crater. Using the ChemCam instrument to make detailed observations of the steep terrain of Mount Sharp at a distance, a French-US team headed by CNRS researcher William Rapin has discovered that the Martian climate alternated between dry and wetter periods, before drying up completely about 3 billion years ago.

Astronomers have found evidence that the first exoplanet that was identified transiting its star could have migrated to a close orbit with its star from its original birthplace further away.

Raindrops on other planets and moons are close to the size of raindrops on Earth despite having different chemical compositions and falling through vastly different atmospheres, a new study finds.

The world's first ground-based observations of the bare nucleus of a comet nearing the end of its active life revealed that the nucleus has a diameter of 800 meters and is covered with large grains of phyllosilicate; on Earth large grains of phyllosilicate are commonly available as talcum powder. This discovery provides clues to piece together the history of how this comet evolved into its current burnt-out state.