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NASA on Tuesday celebrated exceeding expectations during a mission to deflect a distant asteroid, in a sci-fi like test of humanity’s ability to stop an incoming cosmic object from devastating life on Earth.

The fridge-sized Double Asteroid Redirection Test (DART) impactor deliberately smashed into the moonlet asteroid Dimorphos on September 26, pushing it into a smaller, faster orbit around its big brother Didymos, NASA chief Bill Nelson announced.

That changed its orbital period by four percent, or 32 minutes — from 11 hour 55 minutes to 11 hours 23 minutes, bettering an expectation of 10 minutes.

“At some point in the future, if we find an asteroid that is threatening to hit Earth, and would be large enough to really do some damage, thank goodness that we will have had this successful test,” Nelson told AFP.

The asteroid pair loop together around our Sun every 2.1 years, and pose no threat to our planet.

But they are ideal for studying the “kinetic impact” method of planetary defense.

DART’s success as a proof-of-concept has made a reality what was once science fiction — notably films such as “Armageddon,” “Deep Impact,” and “Don’t Look Up.”

Never actually photographed before, Dimorphos, which is 530 feet (160 meters) in diameter or roughly the size of a big Egyptian pyramid, appeared as a speck of light around an hour before impact.

Its egg-like shape and craggy, boulder-dotted surface finally came into clear view in the last few moments, as DART raced toward it at roughly 14,500 miles (23,500 kilometres) per hour.

Pseudo-comet 

In the days that followed, astronomers rejoiced in stunning images of matter spreading out thousands of miles — pictures collected by Earth and space telescopes, as well as a tiny companion satellite that traveled to the zone with DART.

Thanks to its temporary new tail, Dimorphos has turned into a man-made comet.

But quantifying just how well the test worked required an analysis of light patterns from ground telescopes, which took a few weeks to become apparent.

The binary asteroid system, which was around 6.8 million miles (11 million kilometres) from Earth at impact, is visible only as a single dot from the ground.

The dot’s brightness changes as Dimorphos passes in front of Didymos, which is significantly bigger at half-a-mile wide.

Four optical telescopes were involved in measuring the orbital period — all in Chile and South Africa — while two US-based radar telescopes helped confirm the finding, said NASA planetary scientist Nancy Chabot.

The test also showed scientists that the asteroid is less like a solid rock, and more like a “rubbish pile” of boulders bound by mutual gravity.

If an asteroid is more solid, the momentum imparted by a spaceship will be limited. But if significant mass is pushed at high velocity in the opposite direction to impact, there will be an additional boost.

“It looks like the recoil from the ejecta blast off the surface was a substantial contributor to the overall push given to the asteroid,” said NASA scientist Tom Statler at a briefing.

The test will serve as an “anchor point” for simulations and calculations about the outcome of future impacts, he added.

Mass extinction

No known asteroid larger than 140 meters (460 feet) in size — big enough to devastate a city — has a significant chance to hit Earth for the next 100 years, according to NASA.

But wait long enough, and it will happen.

The geological record shows, for example, that a six-mile wide asteroid struck Earth 66 million years ago, plunging the world into a long winter that led to the mass extinction of the dinosaurs along with 75 percent of all species.

The agency plans to launch in 2026 a telescope called the Near-Earth Object (NEO) Surveyor to better characterize potentially hazardous 140-meter asteroids and comets that come within 30 million miles.

So far, less than half of the estimated 25,000 NEOs of 140 meters have been discovered.

Kinetic impact with a spaceship is just one way to defend the planet, albeit the only method possible with current technology.

Should an approaching object be detected early, a spaceship could be sent to fly alongside it for long enough to divert its path via using the ship’s gravitational pull, creating a so-called gravity tractor.

Another option would be launching nuclear explosives to redirect or destroy an asteroid.

NASA believes the best way to deploy such weapons would be at a distance, to impart force without blowing the asteroid to smithereens, which could further imperil Earth.


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A Nearby Supernova May End Dark Matter Search, Claims New Study

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A Nearby Supernova May End Dark Matter Search, Claims New Study

The pursuit of understanding dark matter, which comprises 85 percent of the universe’s mass, could take a significant leap forward with a nearby supernova. Researchers at the University of California, Berkeley, led by Associate Professor of Physics Benjamin Safdi, have theorised that the elusive particle known as the axion might be detected within moments of gamma rays being emitted from such an event. Axions, predicted to emerge during the collapse of a massive star’s core into a neutron star, could transform into gamma rays in the presence of intense magnetic fields, offering a potential breakthrough in physics.

Potential Role of Gamma-Ray Telescopes

The study was published in Physical Review Letters and revealed that the gamma rays produced from axions could confirm the particle’s mass and properties if detected. The Fermi Gamma-ray Space Telescope, currently the only gamma-ray observatory in orbit, would need to be pointed directly at the supernova, with the likelihood of this alignment estimated at only 10 percent. A detection would revolutionise dark matter research, while the absence of gamma rays would constrain the range of axion masses, rendering many existing dark matter experiments redundant.

Challenges in Catching the Event

For detection, the supernova must occur within the Milky Way or its satellite galaxies—an event averaging once every few decades. The last such occurrence, supernova 1987A, lacked sensitive enough gamma-ray equipment. Safdi emphasised the need for preparedness, proposing a constellation of satellites, named GALAXIS, to ensure 24/7 sky coverage.

Axion’s Theoretical Importance

The axion, supported by theories like quantum chromodynamics (QCD) and string theory, bridges gaps in physics, potentially linking gravity with quantum mechanics. Unlike neutrinos, axions could convert into photons in strong magnetic fields, providing unique signals. Laboratory experiments like ABRACADABRA and ALPHA are also probing for axions, but their sensitivity is limited compared to the scenario of a nearby supernova. Safdi expressed urgency, noting that missing such an event could delay axion detection by decades, underscoring the high stakes of this astrophysical endeavour.

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Fastest-Moving Stars in the Galaxy May be Piloted by Aliens, New Study Suggests

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Fastest-Moving Stars in the Galaxy May be Piloted by Aliens, New Study Suggests

Intelligent extraterrestrial civilisations might be utilising stars as massive interstellar vehicles to explore the galaxy, according to a theory proposed by Clement Vidal, a philosopher at Vrije Universiteit Brussel in Belgium. His research suggests that alien species could potentially accelerate their binary star systems to traverse vast cosmic distances. While such a concept is purely hypothetical and unproven, Vidal’s recent paper, which has not undergone peer review, raises intriguing possibilities about advanced extraterrestrial engineering.

Concept of Moving Star Systems

The study was published in the Journal of the British Interplanetary Society. As per a report by LiveScience, the idea revolves around the notion that alien civilisations, instead of building spacecraft for interstellar travel, might manipulate entire star systems to travel across the galaxy. Vidal highlights binary star systems, particularly those involving neutron stars and smaller companion stars, as ideal candidates. Neutron stars, due to their immense gravitational energy, could serve as anchors for devices designed to propel the system by selectively ejecting stellar material.

Vidal explained in the paper that uneven heating or manipulation of magnetic fields on a star’s surface could cause it to eject material in one direction. This process would create a reactionary thrust, propelling the binary system in the opposite direction. The concept provides a way to travel while preserving planetary ecosystems, making it a theoretically viable method for species reliant on their home systems.

Known Examples with High Velocities

Astronomers have identified hypervelocity stars, such as the pulsars PSR J0610-2100 and PSR J2043+1711, which exhibit high accelerations. While their movements are believed to be natural phenomena, Vidal suggests they could be worth further investigation to rule out potential artificial influences.

This theory adds an unconventional angle to the search for intelligent life, expanding possibilities beyond traditional methods of exploration like searching for signals or probes. The research underscores the importance of considering advanced and unconventional methods aliens might employ to navigate the galaxy.

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Hubble Telescope Finds Unexpectedly Hot Accretion Disk in FU Orionis

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Hubble Telescope Finds Unexpectedly Hot Accretion Disk in FU Orionis

NASA’s Hubble Space Telescope has provided new insights into the young star FU Orionis, located in the constellation Orion. Observations have uncovered extreme temperatures in the inner region of its accretion disk, challenging current models of stellar accretion. Using Hubble’s Cosmic Origins Spectrograph and Space Telescope Imaging Spectrograph, astronomers captured far-ultraviolet and near-ultraviolet spectra, revealing the disk’s inner edge to be unexpectedly hot, with temperatures reaching 16,000 kelvins—almost three times the Sun’s surface temperature.

A Star’s Bright Outburst Explained

First observed in 1936, FU Orionis became a hundred times brighter in months and has remained a unique object of study. Unlike typical T Tauri stars, its accretion disk touches the stellar surface due to instabilities. These are caused by the disk’s large mass, interactions with companion stars, or material falling inwards. Lynne Hillenbrand, a co-author from Caltech, in a statement said that the ultraviolet brightness seen exceeded predictions, revealing a highly dynamic interface between the star and its disk.

Implications for Planet Formation

As per a report by NASA, the study holds significant implications for planetary systems forming around such stars. The report further quoted Adolfo Carvalho, lead author of the study, saying that while distant planets in the disk may experience altered chemical compositions due to outbursts, planets forming close to the star could face disruption or destruction. This revised model provides critical insights into the survival of rocky planets in young star systems, he further added.

Future Investigations on FU Orionis

The research team continues to examine spectral emission lines in the collected data, aiming to map gas movement in the star’s inner regions. Hillenbrand noted that FU Orionis offers a unique opportunity to study the mechanisms at play in eruptive young stars. These findings, published in The Astrophysical Journal Letters, showcase the ongoing value of Hubble’s ultraviolet capabilities in advancing stellar science.

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