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NASA is preparing a mission to deliberately smash a spacecraft into an asteroid — a test run should humanity ever need to stop a giant space rock from wiping out life on Earth.

It may sound like science fiction, but the DART (Double Asteroid Redirection Test) is a real proof-of-concept experiment, blasting off at 10:21pm Pacific Time Tuesday (11:51am IST Wednesday) aboard a SpaceX rocket from Vandenberg Space Force Base in California.

The goal is to slightly alter the trajectory of Dimorphos, a “moonlet” around 525 feet (160 metres, or two Statues of Liberty) wide that circles a much larger asteroid called Didymos (2,500 feet in diameter). The pair orbit the Sun together.

Impact should take place in the fall of 2022, when the binary asteroid system is 6.8 million miles (11 million kilometres) from Earth, almost the nearest point they ever get.

“What we’re trying to learn is how to deflect a threat,” NASA’s top scientist Thomas Zuburchen said of the $330 million (roughly Rs. 2,460 crore) project, the first of its kind.

To be clear, the asteroids in question pose no threat to our planet.

But they belong to a class of bodies known as Near-Earth Objects (NEOs), which approach within 30 million miles.

NASA’s Planetary Defense Coordination Office is most interested in those larger than 460 feet in size, which have the potential to level entire cities or regions with many times the energy of average nuclear bombs.

There are 10,000 known near-Earth asteroids 460 feet in size or greater, but none has a significant chance to hit in the next 100 years. One major caveat: scientists think there are still 15,000 more such objects waiting to be discovered.

15,000mph kick

Planetary scientists can create miniature impacts in labs and use the results to create sophisticated models about how to divert an asteroid — but models are always inferior to real world tests.

Scientists say the Didymos-Dimorphos system is an “ideal natural laboratory,” because Earth-based telescopes can easily measure the brightness variation of the pair and judge the time it takes the moonlet to orbit its big brother.

Since the current orbit period is known, the change will reveal the effect of the impact, scheduled to occur between September 26 and October 1, 2022.

What’s more, since the asteroids’ orbit never intersects our planet, they are thought safer to study.

The DART probe, which is a box the size of a large fridge with limousine-sized solar panels on either side, will slam into Dimorphos at just over 15,000 miles an hour.

Andy Rivkin, DART investigation team lead, said that the current orbital period is 11 hours and 55 minutes, and the team expects the kick will shave around 10 minutes off that time.

There is some uncertainty about how much energy will be transferred by the impact, because the moonlet’s internal composition and porosity are not known.

The more debris that’s generated, the more push will be imparted on Dimorphos.

“Every time we show up at an asteroid, we find stuff we don’t expect,” said Rivkin.

The DART spacecraft also contains sophisticated instruments for navigation and imaging, including the Italian Space Agency’s Light Italian CubeSat for Imaging of Asteroids (LICIACube) to watch the crash and its after-effects.

“The CubeSat is going to give us, we hope, the shot, the most spectacular image of DART’s impact and the ejecta plume coming off the asteroid. That will be a truly historic, spectacular image,” said Tom Statler, DART program scientist.

Nuclear blasts

The so-called “kinetic impactor” method isn’t the only way to divert an asteroid, but it is the only technique ready to deploy with current technology.

Others that have been hypothesised include flying a spacecraft close by to impart a small gravitational force.

Another is detonating a nuclear blast close by — but not on the object itself, as in the films Armageddon and Deep Impact — which would probably create many more perilous objects.

Scientists estimate 460-foot asteroids strike once every 20,000 years.

Asteroids that are six miles or wider — such as the one that struck 66 million years ago and led to the extinction of most life on Earth, including the dinosaurs — occur around every 100-200 million years.


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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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