Machine-learning methods lead to discovery of rare "quadruply imaged quasars" that can help solve cosmological puzzles.
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.
A global science collaboration using data from NASA's Neutron star Interior Composition Explorer (NICER) telescope on the International Space Station has discovered X-ray surges accompanying radio bursts from the pulsar in the Crab Nebula. The finding shows that these bursts, called giant radio pulses, release far more energy than previously suspected.
Gale Crater's central sedimentary mound (Aeolis Mons or, informally, Mount Sharp) is a 5.5-km-tall remnant of the infilling and erosion of this ancient impact crater. Given its thickness and age, Mount Sharp preserves one of the best records of early Martian climatic, hydrological, and sedimentary history.
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.
A group led by scientists from the RIKEN Cluster for Pioneering Research, using coordinated observations of the Crab pulsar in a number of frequencies, have discovered that the "giant radio pulses" which it emits include an increase in x-ray emissions in addition to the radio and visible light emissions that had been previously observed. This finding, published in Science, implies that these pulses are hundreds of times more energetic than previously believed.
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.
X-ray emissions from the Crab Pulsar are more intense during giant radio pulses (GRPs), researchers report. The new findings provide constraints on the mechanisms underlying GRPs and may provide insights into other transient radio phenomena observed throughout the Universe.