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NASA’s mission to deflect asteroid is a step towards preparing the world for a potential future asteroid strike like the one which killed the dinosaurs some 66 million years ago, the chances of which are very slim in our lifetime, Indian scientists said.

In a first-of-its-kind mission, the Double Asteroid Redirection Test (DART) spacecraft successfully crashed into an asteroid on Tuesday to test whether space rocks that might threaten Earth in the future could be nudged safely out of the way.

DART – the world’s first planetary defence technology demonstration — targeted the asteroid moonlet Dimorphos, a small body just 160 metres in diameter.

“We are surrounded by several asteroids and comets that orbit our Sun. Very few of them are potentially hazardous to Earth. Hence, It is better to prepare our defenses to avoid such asteroids on a collision course with Earth in the future,” said Chrisphin Karthick, a scientist at the Indian Institute of Astrophysics (IIA), Bengaluru.

Karthick, who is involved in the DART project, noted that the mission “certainly is a step towards” preparing the world for a potential future event like the one which is believed to have led to the extinction of dinosaurs some 66 million years ago.

“This successful DART mission is an example of that. We now know to precisely aim the spacecraft for such a small body. We can also prepare ourselves for the larger body from the post-impact observations of this DART mission,” Karthick told PTI.

Dimorphos orbits a larger 780-metre asteroid called Didymos. Neither asteroid poses a threat to Earth. By comparison, the dinosaur-killing asteroid that hit Earth was about 10 kilometers in diameter.

The DART mission’s one-way trip, confirmed NASA, can successfully navigate a spacecraft to intentionally collide with an asteroid to deflect it, a technique known as kinetic impact.

Goutam Chattopadhyay, a senior scientist at NASA’s Jet Propulsion Laboratory (JPL) in the US also noted that the mission will help to prepare for a future-threatening asteroid.

“DART is an experimental mission to try out a concept of deflecting an asteroid. The idea is, if we can encounter these asteroids whose trajectory is towards us and we do that at a sufficient distance from the Earth, then a minor deflection will be enough to change the path of the asteroid,” he added.

However, scientists noted that most of the asteroids, which are somewhat significant in size and can cause damage on impact with the Earth, have a minuscule chance of hitting the planet.

“However, the probability of that is non-zero and we must always be vigilant. There is always a possibility that a big one might be headed towards us and the question becomes, what would be our approach and how we could mitigate that. That’s why these programs are important,” Chattopadhyay told PTI.

“At least for the next century, there is no such threat from the known asteroids that can cause mass casualties,” said Karthick, adding that this risk assessment is, however, based on the asteroids known to science so far.

Small asteroids are always hitting the Earth all the time but they burn due to the heat generated in the atmosphere. However, for sufficiently large asteroids, that is not the case as the outer core will burn but there will be sufficient mass left to create damage.

The team will now observe Dimorphos using ground-based telescopes to confirm that DART’s impact altered the asteroid’s orbit around Didymos.

Researchers expect the impact to shorten Dimorphos’ orbit by about 1 per cent, or roughly 10 minutes; precisely measuring how much the asteroid was deflected is one of the primary purposes of the full-scale test.

“Post impact, the team will observe Dimorphos using ground-based telescopes to confirm that DART’s impact altered the asteroid’s orbit around Didymos,” Karthick said.

“The expected output of the impact is to shorten Dimorphos’ orbit by about 1 per cent, or roughly 10 minutes. One of the primary goals is to measure the deflection of the asteroid’s orbit,” he added.

However, Chattopadhyay said whether the mission has been able to deflect the orbit of the asteroid will be known only once all the data has been collected.

“I would emphasise that our calculations and small-scale lab experiments show that it might work well,”. he added NASA has a multi prong approach to monitor Near Earth Asteroids (NEAs). The space agency initiated observations program in 1998. Most discoveries are supported by ground-based telescopic surveys, “We primarily use radars and lidars for this. Mostly they are ground-based systems. However, our existing satellites in space are also used to image and track these objects,” the scientist added.

Lidar is a method for determining distance by targeting an object or a surface with a laser and measuring the time for the reflected light.

“The DART mission is humanity’s first attempt to alter the trajectory of an asteroid by crashing a human made object into it. Today’s successful impact is a big step forward in that direction.

“However, to know the eventual success of this concept, we have to wait a few more years by when any significant change in the trajectory would be clearly apparent,” said Dibyendu Nandi, space scientist at Indian Institutes of Science Education and Research, Kolkata.


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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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