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RSTV: SCIENCE MONITOR 31.7.2021

 

RSTV


 

Indian scientists part of team spotting short GRB from collapsing star:

  • A group of astronomers have detected a very short, powerful burst of high-energy radiation that lasted for about a second and had been racing toward Earth for nearly half the present age of the universe.
  • The burst detected by NASA’s Fermi Gamma-ray Space Telescope on August 26, 2020, turned out to be one for the record books – the shortest gamma-ray burst (GRB) caused by the death of a massive star.
  • GRBs are the most powerful events in the universe, detectable across billions of light-years. Astronomers classify them as long or short based on whether the event lasts for more or less than two seconds. They observe long bursts in association with the demise of massive stars, while short bursts have been linked to a different scenario.
  • Such a discovery has helped to resolve the long-standing issues related to gamma-ray bursts. Also, this study triggers to re-analyse all such known events to constrain number densities better.
  • When a star much more massive than the Sun runs out of fuel, its core suddenly collapses and forms a black hole. As matter swirls toward the black hole, some of it escapes in the form of two powerful jets that rush outward at almost the speed of light in opposite directions.
  • Astronomers only detect a GRB when one of these jets happens to point almost directly toward Earth.
  • Each jet drills through the star, producing a pulse of gamma rays – the highest-energy form of light – that can last up to minutes. Following the burst, the disrupted star then rapidly expands as a supernova.
  • Short GRBs, on the other hand, form when pairs of compact objects – such as neutron stars, which also form during stellar collapse – spiral inward over billions of years and collide.
  • GRB 200826A was a sharp blast of high-energy emission lasting just 0.65 seconds. After traveling for eons through the expanding universe, the signal had stretched out to about one second long when it was detected by Fermi’s Gamma-ray Burst Monitor.
  • The event also appeared in instruments aboard NASA’s Wind mission, which orbits a point between Earth and the Sun located about 930,000 miles (1.5 million kilometers) away, and Mars Odyssey, which has been orbiting the Red Planet since 2001. ESA’s (the European Space Agency’s) INTEGRAL satellite observed the blast as well.
  • The discovery helps resolve a long-standing puzzle. While long GRBs must be coupled to supernovae, astronomers detect far greater numbers of supernovae than they do long GRBs.
  • The researchers conclude that collapsing stars producing short GRBs must be marginal cases whose light-speed jets teeter on the brink of success or failure, a conclusion consistent with the notion that most massive stars die without producing jets and GRBs at all. More broadly, this result clearly demonstrates that a burst’s duration alone does not uniquely indicate its origin.

Brain inspired new artificial neuron- IIT Delhi:

  • Human brain is one of the most powerful and intelligent natural computer known to mankind. Neuromorphic computing refers to the field of technology where engineers try to build intelligent machines inspired from the working of mammal brains.
  • Neurons and synapses are believed to be the most important building blocks giving rise to intelligence inside brains.
  • Researchers have invented a new spiking neuron model named as DEXAT (Double EXponential Adaptive Threshold neuron). T
  • The invention is significant as it will help to build accurate, fast and energy-efficient neuromorphic Artificial Intelligence (AI) systems for real world applications like speech recognition.
  • The work, which was partly funded by the Core Research Grant from the Science and Engineering Research Board (SERB), Department of Science and Technology (DST), contributes to the relatively nascent and emerging field of Recurrent Spiking Neural Networks (RSNNs).
  • The work being inter-disciplinary, lies at the intersection of Artificial Intelligence, Neuromorphic Hardware and Nanoelectronics.
  • The study demonstrated neuron model with higher accuracy, faster convergence and flexibility in hardware implementation compared to other state-of-the-art adaptive threshold spiking neurons.
  • The proposed solution achieves high performance with fewer neurons. Benefits of proposed invention were shown on multiple datasets. Classification accuracy of 91% on Google Spoken Commands (GSC) dataset was achieved. A patent has also been filed on this work

Artemis:

  • Artemis– Acceleration, Reconnection, Turbulence and Electrodynamics of Moon’s Interaction with the Sun. It is NASA’s next mission to the Moon.
  • Objective: To measure what happens when the Sun’s radiation hits our rocky moon, where there is no magnetic field to protect it. Artemis was the twin sister of Apollo and goddess of the Moon in Greek mythology.
  • With the Artemis program, NASA will land the first woman and next man on the Moon by 2024.
  • NASA’s powerful new rocket, the Space Launch System (SLS), will send astronauts aboard the Orion spacecraft nearly a quarter million miles from Earth to lunar orbit.
  • Astronauts will dock Orion at the Gateway and transfer to a human landing system for expeditions to the surface of the Moon.
  • They will return to the orbital outpost to board Orion again before returning safely to Earth.
  • The agency will fly two missions around the Moon to test its deep space exploration systems. NASA is working toward launching Artemis I, an uncrewed flight to test the SLS and Orion spacecraft together, followed by the Artemis II mission, the first SLS and Orion test flight with crew. NASA will land astronauts on the Moon by 2024 on the Artemis III mission and about once a year thereafter.
  • Find and use water and other critical resources needed for long-term exploration.
  • Investigate the Moon’s mysteries and learn more about our home planet and the universe.
  • Learn how to live and operate on the surface of another celestial body where astronauts are just three days from home.
  • Prove the technologies we need before sending astronauts on missions to Mars, which can take up to three years roundtrip.