The European Space Agency’s (ESA) Solar Orbiter spacecraft has delivered the most detailed images of the sun’s surface to date. These images, taken in March 2023 from a distance of approximately 74 million kilometres, were released on November 20. They provide unprecedented insights into the photosphere, the layer of the sun responsible for emitting visible light. The photos reveal the intricate and dynamic patterns of granules—plasma cells roughly 1,000 kilometres wide—formed by convection as hot plasma rises and cooler plasma sinks.

Sunspot Activity and Magnetic Fields Analysed

The images highlight sunspots as cooler, darker regions on the photosphere, where intense magnetic fields disrupt the movement of plasma. The Polarimetric and Helioseismic Imager (PHI) on board the Solar Orbiter produced detailed maps of these magnetic fields, identifying their significant concentration in sunspot regions. According to Daniel Müller, ESA Project Scientist for Solar Orbiter, these observations are essential for understanding the sun’s dynamic processes. The sunspots appear colder because magnetic forces restrict normal convection, causing a decrease in surface temperature.

New Data on Solar Rotation and Winds

A velocity map, known as a tachogram, has also been shared, illustrating the speed and direction of material movement on the sun’s surface. Blue regions represent plasma moving towards the spacecraft, while red areas show plasma moving away, revealing the sun’s rotational dynamics. Additionally, magnetic fields in sunspot regions were seen to disrupt the surface material further.

The sun’s outer atmosphere, the corona, was imaged by the spacecraft’s Extreme Ultraviolet Imager. Plasma loops protruding from the sun, visible in these images, are connected to sunspots and contribute to the solar wind. This solar wind, when reaching Earth, often results in auroral displays.

Future Missions to Study Solar Poles

The Solar Orbiter, launched in 2020 as a joint mission with NASA, aims to capture unprecedented views of the sun’s poles. These observations are scheduled for 2025, when the spacecraft’s orbit will align for a direct perspective. The recent imaging involved the assembly of 25 smaller images, a complex process now expected to accelerate for future releases.

Efforts to create a comprehensive map of all human cells have taken a significant leap forward. Researchers associated with the Human Cell Atlas (HCA), a global scientific consortium, have released over 40 studies detailing critical progress in mapping the 37 trillion cells that make up the human body. These findings, published on 20 November in Nature journals, focus on cells in organs such as the lungs, skin, and brain and outline advanced computational tools for analysing vast datasets.

The project aims to profile cells from diverse populations worldwide to identify their unique functions, locations, and interactions at various stages of life. Already, data from 100 million cells sourced from over 10,000 individuals in more than 100 countries have been collected. By 2026, researchers plan to present the first draft of the atlas, with future versions expected to incorporate billions of cells.

Detailed Discoveries Across the Body

Among the recent findings is a comprehensive cellular map of the digestive system, from the oesophagus to the colon. This work, based on data from 190 individuals, uncovered a type of cell involved in inflammatory diseases like Crohn’s disease and ulcerative colitis. Professor Itai Yanai of NYU Langone Health noted that these cells likely trigger immune responses, contributing to inflammation in diseased tissues.

Other studies have shed light on early human development, including insights into skeletal formation during pregnancy and conditions like craniosynostosis. Maps comparing fetal brain development with lab-grown brain organoids also highlight the accuracy of these models, which replicate human brain activity up to the second trimester.

Implications for Medical Research

The findings have implications for drug discovery and disease understanding. Dr Aviv Regev, co-chair of the HCA, likened the work to advancements in mapping technologies, stating, “We have transitioned from basic, crude maps to something as detailed as Google Maps.” However, she acknowledged the significant work that lies ahead to complete this ambitious project.

The research has already led to groundbreaking discoveries, including the identification of a new lung cell type and insights into tissues vulnerable to COVID-19. Scientists aim to continue refining these maps, using organoids and other methods to unravel human biology and disease mechanisms.

Mars’ two moons, Phobos and Deimos, could have originated from the debris of an asteroid torn apart by the planet’s gravity, according to recent simulations. Research published in Icarus suggests this scenario could explain the unique features of these moons, which differ significantly from typical spherical moons seen in the solar system. The potato-like shapes and circular equatorial orbits of these moons have long puzzled scientists, prompting new theories on their formation.

Theories Behind Phobos and Deimos’ Origins

Two primary theories have dominated the discussion on how these moons formed. One posits that they are asteroids captured by Mars’ gravitational pull. However, this hypothesis fails to account for their stable, near-circular orbits. The second theory suggests that Phobos and Deimos may have formed from debris after a massive collision involving Mars. Jacob Kegerreis, a planetary scientist at NASA‘s Ames Research Center, believes a hybrid scenario could provide a plausible answer.

Kegerreis and his team propose that an asteroid may have been captured by Mars’ gravity but was then torn apart, creating a ring of debris. Over time, this material could have coalesced to form the moons, inheriting the circular orbits observed today.

Simulations Offer New Insights

Hundreds of supercomputer simulations were conducted to test the hypothesis. By varying the asteroid’s size, speed, and spin, researchers observed that rings of debris consistently formed under certain conditions. Kegerreis explained that they saw material capable of forming a disk across different scenarios.

Upcoming Mission to Provide Answers

The Japan Aerospace Exploration Agency’s Mars Moons Exploration mission, set for launch in 2026, aims to gather material from Phobos. This analysis could determine whether the moons share a composition with Mars, supporting the collision theory, or resemble asteroids with water-rich compounds, backing the shredded asteroid hypothesis.

Findings from this mission may shed light on Mars’ moons and help understand moon formation around exoplanets, broadening our understanding of planetary systems.