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In a world first, NASA has crashed a spacecraft into an asteroid in an attempt to push the rocky traveler off its trajectory. The Double Asteroid Redirection Test – or DART – is meant to test one potential approach that could prevent an asteroid from colliding with Earth. David Barnhart is a professor of astronautics at the University of Southern California and director of the Space Engineering Research Center there. He watched NASA’s live stream of the successful mission and explains what is known so far.

1. What do the images show?

The first images, taken by a camera aboard DART, show the double asteroid system of Didymos – about 2,500 feet (780 meters) in diameter – being orbited by the smaller asteroid Dimorphos that is about 525 feet (160 meters) long.

As the targeting algorithm on DART locked onto Dimorphos, the craft adjusted its flight and began heading towards the smaller of the two asteroids. The image taken at 11 seconds before impact and 42 miles (68 kilometers) from Dimorphos shows the asteroid centered in the camera’s field of view. This meant that the targeting algorithm was fairly accurate and the craft would collide right at the center of Dimorphos.

The second-to-last image, taken two seconds before impact shows the rocky surface of Dimorphos, including small shadows. These shadows are interesting because they suggest that the camera aboard the DART spacecraft was seeing Dimorphos directly on but the Sun was at an angle relative to the camera. They imply the DART spacecraft was centred on its trajectory to impact Dimorphos at the moment, but it’s also possible the asteroid was slowly rotating relative to the camera.

The final photo, taken one second before impact, only shows the top slice of an image but this is incredibly exciting. The fact that NASA received only a part of the image implies that the shutter took the picture but DART, traveling at around 14,000 miles per hour (22,500 kilometers per hour) was unable to transmit the complete image before impact.

2. What was supposed to happen?

The point of the DART mission was to test whether it is possible to deflect an asteroid with a kinetic impact – by crashing something into it. NASA used the analogy of a golf cart hitting the side of an Egyptian pyramid to convey the relative difference in size between tiny DART and Dimorphos, the smaller of the two asteroids. Prior to the test, Dimorphos orbited Didymos in roughly 16 hours. NASA expects the impact to shorten Dimorphos’ orbit by about 1 percent or roughly 10 minutes. Though small, if done far enough away from Earth, a nudge like this could potentially deflect a future asteroid headed towards Earth just enough to prevent an impact.

3. What do we know already?

The last bits of data that came from the DART spacecraft right before impact show that it was on course. The fact that the images stopped transmitting after the target point was reached can only mean that the impact was a success.

While there is likely a lot of information to be learned from the images taken by DART, the world will have to wait to learn whether the deflection was also a success. Fifteen days before the impact, DART released a small satellite with a camera that was designed to document the entire impact. The small satellite’s sensors should have taken images and collected information, but given that it doesn’t have a large antenna onboard, the images will be transmitted slowly back to Earth, one by one, over the coming weeks.

4. What does the test mean for planetary defense?

I believe this test was a great proof-of-concept for many technologies that the US government has invested in over the years. And importantly, it proves that it is possible to send a craft to intercept with a minuscule target millions of miles away from Earth. From that standpoint DART has been a great success.

Over the course of the next months and years, researchers will learn just how much deflection the impact caused – and most importantly, whether this type of kinetic impact can actually move a celestial object ever so slightly at a great enough distance to prevent a future asteroid from threatening Earth.


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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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