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NASA’s DART spacecraft successfully slammed into a distant asteroid at hypersonic speed on Monday in the world’s first test of a planetary defense system, designed to prevent a potential doomsday meteorite collision with Earth.

Humanity’s first attempt to alter the motion of an asteroid or any celestial body played out in a NASA webcast from the mission operations center outside Washington, DC, 10 months after DART was launched.

The livestream showed images taken by DART’s camera as the cube-shaped “impactor” vehicle, no bigger than a vending machine with two rectangular solar arrays, streaked into the asteroid Dimorphos, about the size of a football stadium, at 7:14 pm EDT (23:14 GMT) some 6.8 million miles (11 million km) from Earth.

The $330 million (roughly Rs. 2,683 crore) mission, some seven years in development, was devised to determine if a spacecraft is capable of changing the trajectory of an asteroid through sheer kinetic force, nudging it off course just enough to keep Earth out of harm’s way.

Whether the experiment succeeded beyond accomplishing its intended impact will not be known until further ground-based telescope observations of the asteroid next month. But NASA officials hailed the immediate outcome of Monday’s test, saying the spacecraft achieved its purpose.

“NASA works for the benefit of humanity, so for us it’s the ultimate fulfillment of our mission to do something like this – a technology demonstration that, who knows, some day could save our home,” NASA Deputy Administrator Pam Melroy, a retired astronaut, said minutes after the impact.

DART, launched by a SpaceX rocket in November 2021, made most of its voyage under the guidance of NASA’s flight directors, with control handed over to an autonomous on-board navigation system in the final hours of the journey.

Monday evening’s bullseye impact was monitored in near real time from the mission operations center at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland.

Cheers erupted from the control room as second-by-second images of the target asteroid, captured by DART’s onboard camera, grew larger and ultimately filled the TV screen of NASA’s live webcast just before the signal was lost, confirming the spacecraft had crashed into Dimorphos.

DART’s celestial target was an oblong asteroid “moonlet” about 560 feet (170 meters) in diameter that orbits a parent asteroid five times larger called Didymos as part of a binary pair with the same name, the Greek word for twin.

Neither object presents any actual threat to Earth, and NASA scientists said their DART test could not create a new hazard by mistake.

Dimorphos and Didymos are both tiny compared with the cataclysmic Chicxulub asteroid that struck Earth some 66 million years ago, wiping out about three-quarters of the world’s plant and animal species including the dinosaurs.

Smaller asteroids are far more common and present a greater theoretical concern in the near term, making the Didymos pair suitable test subjects for their size, according to NASA scientists and planetary defense experts. A Dimorphos-sized asteroid, while not capable of posing a planet-wide threat, could level a major city with a direct hit.

Also, the two asteroids’ relative proximity to Earth and dual configuration make them ideal for the first proof-of-concept mission of DART, short for Double Asteroid Redirection Test.

Robotic suicide mission

The mission represented a rare instance in which a NASA spacecraft had to crash to succeed. DART flew directly into Dimorphos at 15,000 miles per hour (24,000 kph), creating the force scientists hope will be enough to shift its orbital track closer to the parent asteroid.

APL engineers said the spacecraft was presumably smashed to bits and left a small impact crater in the boulder-strewn surface of the asteroid.

The DART team said it expects to shorten the orbital path of Dimorphos by 10 minutes but would consider at least 73 seconds a success, proving the exercise as a viable technique to deflect an asteroid on a collision course with Earth – if one were ever discovered.

A nudge to an asteroid millions of miles away years in advance could be sufficient to safely reroute it.

Earlier calculations of the starting location and orbital period of Dimorphos were made during a six-day observation period in July and will be compared with post-impact measurements made in October to determine whether the asteroid budged and by how much.

Monday’s test also was observed by a camera mounted on a briefcase-sized mini-spacecraft released from DART days in advance, as well as by ground-based observatories and the Hubble and Webb space telescopes, but images from those were not immediately available.

DART is the latest of several NASA missions in recent years to explore and interact with asteroids, primordial rocky remnants from the solar system’s formation more than 4.5 billion years ago.

Last year, NASA launched a probe on a voyage to the Trojan asteroid clusters orbiting near Jupiter, while the grab-and-go spacecraft OSIRIS-REx is on its way back to Earth with a sample collected in October 2020 from the asteroid Bennu.

The Dimorphos moonlet is one of the smallest astronomical objects to receive a permanent name and is one of 27,500 known near-Earth asteroids of all sizes tracked by NASA. Although none are known to pose a foreseeable hazard to humankind, NASA estimates that many more asteroids remain undetected in the near-Earth vicinity.

© Thomson Reuters 2022


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Voyager 2’s Flyby Sheds Light on Uranus’s Magnetic Mystery

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Voyager 2's Flyby Sheds Light on Uranus's Magnetic Mystery

A recent analysis of 38-year-old data from NASA’s Voyager 2 spacecraft has provided fresh insights into the unique magnetosphere of Uranus, according to a study published on November 11 in Nature Astronomy. During Voyager 2’s 1986 flyby, Uranus’ magnetosphere was found to be unexpectedly distorted by a blast of solar wind. The findings suggest that the planet’s magnetic field behaves unlike any other in the solar system.

Findings Highlight Unusual Magnetic Structures

Jamie Jasinski, a planetary scientist at NASA’s Jet Propulsion Laboratory and California Institute of Technology, and lead author of the study, noted that Voyager 2’s timing happened to coincide with an intense solar wind event, a rare occurrence near Uranus. This compression of Uranus’s magnetosphere, seen only around 4% of the time, is thought to be responsible for the unique measurements Voyager captured. Had the spacecraft arrived even a week earlier, Jasinski observed, these conditions would likely have been different, possibly leading to alternative conclusions about Uranus’s magnetic characteristics.

Unlike Earth, Uranus exhibits a complex “open-closed” magnetic process, influenced by its extreme axial tilt. This tilt subjects Uranus to highly variable solar wind effects, resulting in a magnetosphere that opens and closes cyclically.

Implications for Future Uranus Exploration

The study’s conclusions go beyond Uranus itself, offering insights into the magnetic behaviours of its outermost moons, including Titania and Oberon. These moons, it turns out, lie within Uranus’s magnetosphere rather than outside it, making them candidates for investigations into subsurface oceans through magnetic field detection. As Jasinski highlighted, these conditions would simplify detecting any magnetic signatures that suggest liquid beneath the moons’ icy surfaces.

While Voyager 2 remains the only mission to visit Uranus, the study’s findings underscore a growing interest in exploring the ice giant in greater detail.

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Tajikistan rock shelter reveals ancient human migration routes

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Tajikistan rock shelter reveals ancient human migration routes

Archaeologists have uncovered a rock shelter in Tajikistan’s Zeravshan Valley that was occupied by multiple human species, including Neanderthals, Denisovans, and Homo sapiens, for over 130,000 years. Discovered along the Zeravshan River in the Inner Asian Mountain Corridor (IAMC), this site, known as Soii Havzak, provides new insight into the migration patterns of ancient humans. Researchers believe the IAMC may have facilitated interactions between these groups, offering clues about how they lived and possibly coexisted in Central Asia.

Discovery Along the Zeravshan River

A team led by Dr Yossi Zaidner, senior lecturer at the Institute of Archaeology at the Hebrew University of Jerusalem, recently excavated the site. Evidence of various human occupations was found, including stone tools and animal bones dating from 150,000 to 20,000 years ago. Zaidner noted that Central Asia’s IAMC could have served as a natural migration route, allowing distinct human populations to cross paths. “This discovery is crucial for understanding ancient human presence in Central Asia and how different human species may have interacted here,” he stated in a press release.

Significance for Human Migration and Interaction

Artifacts from Soii Havzak, including stone blades, rock flakes, crafted flints, and signs of fire use, suggest repeated use of the shelter by different human groups. The find highlights Central Asia’s significance in ancient migration routes, with the Zeravshan River likely serving as a pathway for early humans as they dispersed across continents.

A Pathway for Ancient Civilisations

Beyond its prehistoric importance, the Zeravshan Valley later became a key route on the Silk Road, linking distant civilisations such as China and Rome. Researchers expect further studies at Soii Havzak to shed light on the broader implications of this region in ancient human migration and cross-cultural interactions, aiming to deepen understanding of human history and evolution during the Middle Paleolithic era.

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NASA’s Juno shows Jupiter’s storms and moon Amalthea up close

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NASA’s Juno shows Jupiter’s storms and moon Amalthea up close

NASA’s Juno spacecraft has delivered breathtaking images of Jupiter, highlighting the planet’s swirling, multicoloured storms and unique moons. During Juno’s 66th close flyby on October 23, the spacecraft approached the planet’s polar regions and captured close-up views of its fifth-largest moon, Amalthea. The raw images collected by JunoCam have since been processed by citizen scientists, who enhanced colours and contrasts to reveal Jupiter’s atmospheric details in a new light.

Spectacular Details of Jupiter’s Storms Revealed

Citizen scientist Jackie Branc processed one of Juno’s most striking images, showcasing a region on Jupiter called a Folded Filamentary Region (FFR), located near the planet’s subpolar areas. FFRs are known for their complex cloud patterns, which include white billows and fine, thread-like filaments. This recent image captures Jupiter’s stormy atmosphere with an emphasis on these fine details, giving scientists and the public alike a vivid view of the planet’s dynamic weather systems.

Juno’s data, available to the public online, allows enthusiasts and researchers to adjust image features such as contrast and colour balance. This collaborative effort has enabled a range of perspectives on Jupiter’s atmospheric bands, turbulent clouds, and powerful vortices.

Amalthea: A Close-Up of Jupiter’s Unique Moon

Juno also captured images of Amalthea, a small, potato-shaped moon only 84 kilometres in radius. In images processed by Gerald Eichstädt, the white balance was adjusted to distinguish Amalthea from the blackness of space, presenting the moon in stark relief. This view of Amalthea, with its rugged, irregular shape, adds to our understanding of Jupiter’s complex satellite system.

Launched in 2016, the Juno mission was originally planned to conclude in 2021, but its mission has been extended, with plans to end in September 2025. When its mission concludes, Juno will plunge into Jupiter’s atmosphere, marking the end of its successful exploration journey.

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