Cosmochemists have discovered the oldest solid material known to exist on Earth. The material, stardust, consists of silicon carbide grains measuring around one micrometer in size. The grains date back approximately 7 billion years, or about 2.5 billion years before the Sun and solar system formed. Aged stars nearing the end of their life cycles originally forged the grains, which then were captured inside a meteorite that formed around 4.6 billion years ago, eventually crashing into Australia in 1969. Analyzing the dust will help scientists study previous stellar generations in our galaxy. See also: Milky Way Galaxy; Star; Sun

Since its landing in 2012, NASA’s Curiosity rover has been analyzing Martian soils and rocks for evidence that the Red Planet could have supported life in its past. So far, Curiosity has found carbon, hydrogen, oxygen, phosphorus, sulfur, methane, and organic molecules. In addition, Curiosity has found evidence of surface water and groundwater. All these discoveries suggest favorable chemistry and conditions for supporting life, although not evidence of life. Most recently, scientists reported in the journal Geophysical Research Letters (September 2017) the discovery of the element boron, which may have acted as a stabilizer for the molecular precursors of life. See also: Boron; Mars Science Laboratory; Robot rover Curiosity lands on Mars; Prebiotic organic synthesis; Space probe

The nearest images of the Sun obtained to date have revealed a new phenomenon, dubbed campfires, which appear as small, bright flickers of light all over the Sun's surface. The Solar Orbiter, a European Space Agency spacecraft launched in February 2020, captured the images from a distance of 77 million km (48 million mi), or about half the distance between Earth and the Sun. The Solar Orbiter will gather vastly more and better observations of campfires as the probe's mission continues for at least the next seven years, with a flight path that will ultimately take the probe to a distance of less than 0.3 astronomical units from the Sun, reaching inside the orbit of Mercury. [An astronomical unit is the average Sun–Earth distance of about 150 million km (93 million mi)]. See also: Astronomical unit

Obscured by a hazy atmosphere 100 times thicker than Earth's, Venus is a notoriously difficult world to study. Ground temperatures on Venus exceed 450°C (842°F)—enough to melt lead and to have quickly degraded the Soviet robotic landers last placed there 40 years ago. Yet orbiting spacecraft have successfully mapped this planet with cloud-piercing radar, as well as identified constituent surface materials via narrow bands of infrared light that escape the Venusian atmosphere. Those investigations have revealed unmistakable volcanic structures and solidified lava flows, although there remains no definitive evidence as to whether volcanic eruptions still occur. Now, a new study suggests that such evidence is already in hand and points to Venus as the only other volcanically active planet in the solar system. See also: Atmosphere; Radar; Venus; Volcano

Dawn, a pioneering mission to our solar system's asteroid belt, has gone silent. In late October 2018, Dawn ran out of hydrazine, the thruster fuel needed to orient the spacecraft for communication with Earth and the generation of solar power. Although now retired, the Dawn mission leaves a rich scientific legacy. It is the first and only spacecraft to have visited the dwarf planet Ceres—the largest object in the asteroid belt between Mars and Jupiter—as well as Vesta, the second-largest object in the belt. Before Dawn's arrivals, humanity had little clue as to what these worlds really looked like. See also: Asteroid; Ceres; Earth; Dawn mission; Hydrazine; Jupiter; Mars; Planet; Solar cell; Solar system; Space communications; Vesta

NASA's Curiosity rover has produced new key evidence in determining whether Mars has ever hosted life. While drilling in an ancient lakebed, Curiosity recently discovered organic material more complex and abundant than previously found on the Red Planet. On Earth, chains of organic molecules, which contain the element carbon, form the basic building blocks of life. Far more investigation will be necessary, however, to identify the source of the Martian material as either biological or geological. Besides life, likelier sources of the organic material include impacting asteroids and volcanism. See also: Asteroid; Astrobiology; Carbon; Geology; Mars; Organic chemistry; Volcano

On October 19, 2017, astronomers discovered the first interstellar object ever known to have visited our solar system. An asteroid bestowed with the Hawaiian name ‘Oumuamua, meaning “scout,” it was initially detected as a fast-moving point of light between the orbits of Earth and Mars by the Pan-STARRS telescope in Hawaii. Several ground-based telescopes around the world then made subsequent, detailed observations before the asteroid became lost to view during its rapid return to interstellar space. This observation campaign brought forth another surprise: ‘Oumuamua is approximately 10 times as long as it is wide, giving it a cigar-like shape unlike any other cosmic body on record. See also: Asteroid; Comet; Solar system; Telescope

Europa, one of the four largest natural satellites, or moons, orbiting the planet Jupiter, may be the first planetary body in the solar system other than Earth to show evidence of plate tectonics, a research team from the University of Idaho and Johns Hopkins University reported in Nature Geoscience (September 2014). The evidence comes from images sent back from the Galileo spacecraft, which passed Europa 17 times during its orbit of Jupiter between 1995 and 2003. See also: Galileo mission (Jupiter); Galileo observations of Jovian satellites; Jupiter; Satellite (astronomy); Solar system; Space probe

On August 23, 2023, at 6:04 pm India Standard Time, the lander module of the Indian Space Research Organization (ISRO)'s Chandrayaan-3 mission touched down on the lunar surface. The landing marks the first time a space probe has landed in the Moon's southern polar region, an area that is significant scientifically and for future human exploration of Mars and beyond. See also: Moon; Space probe; Space probe missions

The ice-covered moon Europa has long intrigued researchers as a potential abode for extraterrestrial life. Although its orbit around Jupiter is frigidly far from the Sun, Europa harbors an internal ocean. Furthermore, this inner liquid reservoir likely receives warming energy due to gravitational interactions amongst Jupiter and its numerous moons. Understandably keen to study Europa's innards, scientists have pinned their hopes on a future robotic lander that might drill through the moon's frozen shell. New findings from an old spacecraft, however, have strongly indicated that plumes of material can escape from Europa's inner ocean into space, offering a far simpler way to learn Europa's secrets. See also: Gravity; Jupiter; Ocean; Sun