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About 4.3 billion years ago, soon after the formation of the Sun, a giant asteroid slammed into the far side of the Moon, resulting in one of the biggest impact craters in the Solar system, known as the South Pole-Aitken or SPA basin. This is the largest crater on the Moon, spanning nearly 2,000 km north to south and 1,600 km in the east-west direction. The asteroid struck a glancing blow instead of a head-on impact, resulting in the oblong crater. New analysis indicates that the shape of the SPA basin narrows in the south, indicating that the impactor struck from the north. It was previously believed that the impactor struck from the south. The new research suggests that the down-range end of the basin should be covered by a thick layer of material ejected from the interior of the Moon, which contained a magma ocean, with very little such material up-range from the crater. Scientists have long known that the far side of the Moon is geochemically different from the near side, which...
Astronomers have directly captured the winding motion of spiral structures in a planet-forming disc for the first time. These spirals have been observed dynamically twisting around the young star IM Lupi, providing a window into the earliest stages of the formation of a planetary system. Stars form from dense clouds of gas and dust in stellar nurseries, that feed on the surrounding material under the influence of gravity, increasing in temperature and pressure till the conditions can sustain the fusion of hydrogen into helium. The remaining planets are formed in the leftover debris surrounding the newborn star, which is flattened into a disc because of a slight initial motion. Astronomers know of over 6,000 exoplanets so far, but the exact process by which these worlds are formed are not entirely clear. Planets are believed to be assembled in the protoplanetary discs surrounding newborn stars. The spiral structures in these discs are believed to play an important role in the process...
Astronomers from the International Centre for Radio Astronomy Research (ICRAR) have assembled the largest low-frequency radio colour image of the Milky Way as seen from the Southern Hemisphere. The image allows astronomers to study the birth, evolution and death of stars in the Galaxy. The new image significantly improves the resolution, sensitivity and sky coverage, allowing for a more detailed and comprehensive study of the Milky Way, providing astronomers with a wealth of novel data and insights. The researchers were focused on studying supernova remnants, expanding clouds of gas and dust surrounding dead stars. Hundreds of these supernova remnants are known, but astronomers suspect there may be thousands more. Data from two extensive surveys were combined by supercomputers to assemble the image. The surveys were conducted using the Murchison Widefield Array (MWA) and the Murchison Radio-Astronomy Observatory, both in Western Australia. These surveys were known as the...
Humans know of over 6,000 exoplanets, out of which over 2,000 are similar to Neptunes. Worlds that are smaller than Neptune are expected to make up most of the exoplanets in the galaxy, made up of a mixture of rock and metal with thick atmospheres dominated by hydrogen, helium and maybe water. While these planets are expected to be common in orbits around other stars, scientists understand very little about them because of a lack of similar worlds in our own Solar System. It was previously believed that mini-Neptunes were generally covered in planet-wide oceans of molten magma. New research however indicates that most of them may actually have solid surfaces because of the extreme pressure of the thick atmospheres. The launch of the James Webb Space Telescope moved exoplanetary science from an era of discovery, where new exoplanets were found, to an era of characterisation, where it became possible to start better understanding these distant worlds. The masses of the exoplanets can...
Globular Clusters are stable associations of thousands of stars that assume a spherical shape under the influence of gravity and remain together stably. They are considered the building blocks of galaxies, and are among the oldest and most enigmatic stellar associations in the universe. Researchers have now developed a new model for the formation of star clusters, demonstrating how they were shaped and influenced by extremely massive stars (EMS) containing more than 1,000 times the mass of the Sun. The research indicates that these stellar giants that burned through their fuel rapidly profoundly influenced the chemistry of globular clusters. Globular clusters are found in nearly all galaxies, including the Milky Way, and most of them are around 10 billion years old. These globular clusters formed shortly after the Big Bang, but contain a wide variety of chemical signatures including helium, nitrogen, oxygen, sodium, magnesium and aluminum that could only have been cooked in the...
The Pleiades Star cluster, known as the Krittika Nakshatra in India is also known as the 'Seven Sisters ', and is at a distance of about 440 lightyears from the Earth in the constellation of Taurus. It is a prominent star cluster visible to the naked eye, and can easily be spotted in the winters. Data from NASA 's Transiting Exoplanet Survey Satellite (TESS) and ESA 's Gaia space telescope has revealed that the Seven Sisters have thousands of hidden siblings, revealing that the Pleiades star cluster is 20 times larger than previously believed. The sprawling structure is called the Greater Pleiades Complex. A paper describing the findings has been published in The Astrophysical Journal . Most stars, including the Sun are born in groups, from dense knots within stellar nurseries. Over time, these can form open clusters such as Pleiades, where the stars slowly drift apart, or can form a roughly spherical accumulation under the influence of gravity, known as...
Ancient crocodiles were equally at home in land and water, with some species of 'drop crocs ' ambushing prey from treetops like leopards, and others galloping on hardened claws resembling hooves. New research indicates that as crocodiles evolved to live in water, they became more streamlined and flatter, allowing them to swim better while compromising on the strength of their bites. The research addresses long-standing questions on the trade-offs between bite strength and aquatic adaptations in crocodiles and other aquatic predators that evolved from land-dwelling ancestors. The research indicates that the dome-shaped skulls of the terrestrial ancestral crocodiles were mush stronger and more efficient than the flattened skulls of the modern semi-aquatic crocodiles. The researchers examined Cretaceous fossils from the Bauru Basin in Brazil that preserves a diverse variety of crocodyliforms, a wide group that includes modern crocodiles as well as their extinct cousins....
Astronomers have detected the most distant and powerful flare from a supermassive black hole. The flare was initially flagged by the Zwicky Transient Facility that scans the skies for objects that appear to change their luminosities or positions, in 2018. Over a period of months, the flare increased in luminosities by a factor of 40, and at its peak intensity was 30 times brighter than any previous flare spotted from a supermassive black hole. The flare was of comparable intensity to 10 trillion Suns. The most likely explanation for the flare is that the supermassive black hole snacked on a star that wandered too close, spaghettifying it in a tidal disruption event (TDE). The supermassive black hole in question is actively feeding on the gas and dust in the surrounding galaxy, and forms an active galactic nucleus (AGN), that can outshine all the stars in the surrounding galaxy. This AGN is designated as J2245+3743 and is estimated to contain about 500 solar masses. The object is at...
Astronomers have observed a magnetically steered streamer of gas funneling star-forming material into a new binary system in the constellation of Perseus. This is the first time that such a streamer has been directly observed. The detection was made by the ground based Atacama Large Millimeter/submillimeter Array (ALMA) instrument located in the deserts of Northern Chile. Stars are born from dense clouds of gas and dust that collapse under the influence of gravity, drawing in more gas and dust till the conditions, increasing the temperature and pressure till the fusion of hydrogen into helium can be sustained, marking the birth of a star. The detection of the magnetically steered streamer funneling material into the newborn star system adds to recent observations that indicate that the process of star birth is far more dynamic than previously believed. The data revealed dust and molecules swirling around the newborn binary star system, designated as SVS13A, revealing that the...
On 11 November, two combined coronal mass ejections (CMEs) reached the Earth, inducing a severe geomagnetic storm. The CMEs were associated with a pair of X-class flares from a cluster of sunspots designated as Active Region (AR) 4274 or Sunspot Group 687. The region had erupted in three X-class flares in as many days, with the CME from the third flare, an X5.1 solar flare reaching the Earth early on the morning of 13 November. This was the sixth strongest solar flare in the ongoing solar cycle , Solar Cycle 25, and the first X-class flare since June. The region grew in size and complexity on the far side of the Sun, and has fired off four X-class flares after rotating into view. According to the Center of Excellence in Space Sciences India (CESSI) hosted by the Indian Institute of Science Education and Research (IISER) in Kolkata, “CME3 from AR 14274 associated with the X5.2 solar flare has impacted near-Earth space just before 20:00 UTC on 12 November with a shock speed upwards...
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