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Subject: Science and Technology

  • India’s first indigenous Overhauser Magnetometer

    magnet

    Indian scientists have developed an indigenous Overhauser Magnetometer, one of the most accurate magnetometers extensively used by all magnetic observatories around the world.

    What are Overhauser Magnetometers?

    • A magnetometer is a scientific instrument used to measure the strength and direction of the magnetic field.
    • OVH magnetometers are known for their higher accuracy, higher sensitivity, and efficient power consumption.
    • They find applications in all magnetic observatories worldwide as well as in international space programs.
    • It has so far been imported for such purposes in India.

    Feats achieved

    • The performance of this indigenously made magnetometer is at par with a commercial OVH sensor that is currently installed at the magnetic observatories of IIG.
    • The Indian OVH sensor reproduced the geomagnetic diurnal variations accurately and precisely.
    • It showed the signatures of various space weather events such as geomagnetic storms, sudden impulses, etc.
    • It would also be of potential help to develop a sensitive magnetic resonance imaging (MRI) instrument.

    Benefits of OVH magnetometers

    • OVH magnetometers reduce the cost of sampling and sensing experiments essential for geomagnetic sampling.
    • It can reduce India’s dependence on commercial OVH magnetometers for performing geomagnetic field measurements.

     

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  • GEAC gives its nod for commercial cultivation of GM mustard yet again

    mustard

    The Genetic Engineering Appraisal Committee (GEAC) has yet again cleared the proposal for commercial cultivation of genetically modified (GM) mustard.

    What exactly is GM (Hybridized) Mustard?

    • Hybridization involves crossing two genetically dissimilar plant varieties that can even be from the same species.
    • The first-generation (F1) offspring from such crosses tend to have higher yields than what either parent can individually give.
    • Such hybridization isn’t easy in mustard, as its flowers have both female (pistil) and male (stamen) reproductive organs, making the plants largely self-pollinating.
    • Since the eggs of one plant cannot be fertilised by the pollen grains from another, it limits the scope for developing hybrids.

    How has hybridisation been achieved in mustard?

    • This has been done by genetic modification (GM).
    • Scientists at Delhi University’s Centre for Genetic Manipulation of Crop Plants (CGMCP) have developed the hybrid mustard DMH-11.
    • It contains two alien genes isolated from a soil bacterium called Bacillus amyloliquefaciens.
    • The first gene (‘barnase’) codes for a protein that impairs pollen production and renders the plant into which it is incorporated male-sterile.
    • This plant is then crossed with a fertile parental line containing, in turn, the second ‘barstar’ gene that blocks the action of the barnase gene.
    • The resultant F1 progeny is both high-yielding and also capable of producing seed/ grain, thanks to the barstar gene in the second fertile line.

    How did researchers achieve this?

    • The CGMCP scientists have deployed the barnase-barstar GM technology to create what they say is a robust and viable hybridisation system in mustard.
    • This system was used to develop DMH-11 by crossing a popular Indian mustard variety ‘Varuna’ (the barnase line) with an East European ‘Early Heera-2’ mutant (barstar).
    • DMH-11 is claimed to have shown an average 28% yield increase over Varuna in contained field trials carried out by the Indian Council of Agricultural Research (ICAR).

    What has GEAC now done?

    • GEAC has recommended the environmental release of DMH-11 for its seed production and testing prior to commercial release.
    • In other words, it has given the green signal for commercial cultivation by farmers, with production of seed material being the first step.
    • This move was earlier vetoed in 2016 by Environment Ministry.

    Why did it take so long for GEAC to clear?

    • There has been opposition to GM crops in general, from assorted green groups.
    • Major concern is the presence of a third ‘bar’ gene, which makes GM mustard plants tolerant to the spraying of glufosinate ammonium, a chemical used for killing weeds.
    • This, the opponents allege will cause displacement of manual labour engaged in weeding by promoting use of chemical herbicides.
    • Another concern is over GM mustard threatening or undermining the population of honey bees.
    • Mustard flowers are a source of nectar for honey bees and many other pollinator insects.

    Try this PYQ:

    Q.With reference to the Genetically Modified mustard (GM mustard) developed in India, consider the following statements:

    1. GM mustard has the genes of a soil bacterium that give the plant the property of pest-resistance to a wide variety of pests.
    2. GM mustard has the genes that allow the plant cross-pollination and hybridization.
    3. GM mustard has been developed jointly by the IARI and Punjab Agricultural University.

    Which of the statements given above is/are correct?

    (a) 1 and 3 only

    (b) 2 only

    (c) 2 and 3 only

    (d) 1, 2 and 3

     

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    Back2Basics: Genetic Engineering Appraisal Committee (GEAC)

    • The GEAC is a statutory body notified under the Environment (Protection) Act, 1986.
    • It was formed as the Genetic Engineering Approval Committee and was renamed to its current name in 2010.
    • It functions under the Ministry of Environment, Forests & Climate Change.
    • The body regulates the use, manufacture, storage, import, and export of hazardous microorganisms or genetically-engineered organisms and cells in India.

     

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  • ISRO launches 36 satellites through its heaviest rocket LVM3

    lvm3

    The ISRO’s heaviest rocket, Launch Vehicle Mark 3 (LVM3 or GSLV Mark 3) has successfully put into orbit 36 satellites of the U.K.-based OneWeb.

    Also in news

    • The ISRO has renamed the Geosynchronous Satellite Launch Vehicle (GSLV) Mark -III as Launch Vehicle Mark-III, mainly to identify its task of placing satellites into a variety of orbits.

    What is LVM3?

    • LVM3 (erstwhile GSLV) is an expendable space launch vehicle designed, developed, and operated by the ISRO to launch satellites and other space objects into Geosynchronous Transfer Orbits.
    • It is 49.13 m tall and tallest among all other vehicles of ISRO.
    • It is a three-stage vehicle with a lift-off mass of 420 tonnes.
    • ISRO first launched LVM3 on April 18, 2001 and has made 13 launches since then.

    Stages in LVM3

    • The first stage comprises S139 solid booster with 138-tonne propellant and four liquid strap-on motors, with 40-tonne propellant.
    • The second stage is a liquid engine carrying 40-tonne of liquid propellant.
    • The third stage is the indigenously built Cryogenic Upper Stage (CUS) carrying 15-tonne of cryogenic propellants.

    Difference between PSLV and LVM3

    • LVM3 has the capability to put a heavier payload in the orbit than the Polar Satellite Launch Vehicle (PSLV).
    • PSLV can carry satellites up to a total weight of 2000 kg into space and reach up to an altitude of 600-900 km.
    • LVM3 can carry weight up to 5,000 kg and reach up to 36,000 km.
    • PSLV is designed mainly to deliver earth observation or remote sensing satellites, whereas, LVM3 has been designed for launching communication satellites.
    • LVM3 delivers satellites into a higher elliptical orbit, Geosynchronous Transfer Orbit (GTO) and Geosynchronous Earth Orbit (GEO).

    Upgrades brought by LVM3

    • The LVM3 is capable of lifting much heavier satellites than the GSLV Mk II with a bigger cryogenic upper stage and a larger first stage.
    • Both GSLV Mk II and LVM3 are three-stage vehicles, while the PSLV, which launches to low earth polar orbits, is a four-stage vehicle.
    • The GSLV Mk-II can place up to 2,500kg in geosynchronous orbits and up to 5,000kg to low earth orbit.
    • By comparison, the LVM3 can lift 4,000kg to GTO and up to 8,000 kg to LEO.

     

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  • Five new varieties to expand India’s Basmati platter

    basmati

    Five new Basmati varieties, developed by a group of scientists from Indian Agriculture Research Institute (IARI), in 2020 and 2021 are all set to bring revolutionary changes in the way this type of paddy is cultivated in the country.

    About Basmati Rice

    • Basmati, pronounced is a variety of long, slender-grained aromatic rice which is traditionally grown in India, Pakistan, and Nepal.
    • As of 2019, India accounted for 65% of the international trade in basmati rice, while Pakistan accounted for the remaining 35%.
    • Many countries use domestically grown basmati rice crops; however, basmati is geographically exclusive to certain districts of India and Pakistan.
    • India accounts for over 70% of the world’s basmati rice production.
    • The areas which have a geographical indication are in the states of Punjab, Haryana, Himachal Pradesh, Delhi, Uttarakhand, Western Uttar Pradesh and Jammu and Kashmir

    Export potential of Basmati

    • Basmati rice has a market abroad and brings about â‚č30,000 crore in foreign exchange every year.
    • While 75% of the export is to West Asian countries, European Union countries also import Indian Basmati.
    • However, recently, the export to EU countries faced certain hurdles due to the increase in the pesticide residue levels in the rice from India.

     

     

  • India tests medium-range ballistic missile Agni Prime

    agni

    India has successfully test-fired indigenously-developed new generation medium-range ballistic missile Agni Prime from the Odisha coast.

    Agni-Prime Missile

    • Agni-P is a new generation advanced variant of the Agni class of missiles.
    • It is the sixth missile in the Agni series of ballistic missile.
    • It is a two-staged canisterised missile with a range capability between 1,000 and 2,000 km.
    • Many advanced technologies including composites, propulsion systems, innovative guidance and control mechanisms and state-of-the-art navigation systems have been introduced.
    • Significantly, it weighs 50 per cent less than the Agni 3 missile and has new guidance and propulsion systems
    • The missile strengthens India’s credible deterrence capabilities.

    Back2Basics: Agni Missiles

    agni

    • Agni missiles are long range, nuclear weapons capable surface to surface ballistic missile.
    • The first missile of the series, Agni-I was developed under the Integrated Guided Missile Development Program (IGMDP) and tested in 1989.
    • After its success, Agni missile program was separated from the IGMDP upon realizing its strategic importance.
    • It was designated as a special program in India’s defence budget and provided adequate funds for subsequent development.

    Variants of Agni missiles

    1. Agni I: It is a Medium Range Ballistic Missile with a Range of 700-800 km.
    2. Agni II: It is also a Medium Range Ballistic Missile with a Range more than 2000 km.
    3. Agni III: It is also an Inter-Medium Range Ballistic Missile with Range of more than 2,500 Km
    4. Agni IV: It is also an Inter-Medium Range Ballistic Missile with Range is more than 3,500 km and can fire from a road mobile launcher.
    5. Agni-V: Currently it is the longest of Agni series, an Inter-Continental Ballistic Missile (ICBM) with a range of over 5,000 km.
    6. Agni- VI: The longest of the Agni series, an Inter-Continental Ballistic Missile (ICBM) with a range of ICBM 11,000–12,000 km.

     

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  • What is Web 3.0?

    web

    India has a rapidly-growing Web3 ecosystem with more than 450 active start-ups in the space that raised $1.3 billion in funding till April 2022.

    What is Web 3.0?

    • Web3 help users interact with decentralized applications built on blockchain technology.
    • Web3 technologies like distributed ledgers, artificial intelligence, Metaverse and others aim to create the next-generation internet, which is accessible to everyone and offers benefits.
    • Web2 is what we know and use today.

    Why need Web 3?

    • Centralization has helped onboard billions of people to the World Wide Web (www) and created the stable, robust internet infrastructure.
    • At the same time, a handful of centralized entities have a stronghold on large swathes of the World Wide Web.
    • They unilaterally decide what should and should not be allowed over Internet.

    Key features of a Web3

    • Immutable ecosystem, i.e., trust that people will download the digital product just as the original creator intended.
    • Enhanced transparency and security,
    • Quicker browsing performance,
    • Complete user anonymity and confidentiality,
    • Integrating cryptocurrency wallets with multiple blockchains,
    • Complete control over the content due to decentralization.

    Evolution of (world-wide) web

    • The Web most of us know today is quite different from originally imagined.
    • To understand this better, it’s helpful to break the Web’s short history into loose periods—Web 1.0 and Web 2.0.

    (1) Web 1.0: Read-Only (1990-2004)

    • The first inception of ‘Web 1.0’, occurred roughly between 1990 to 2004.
    • It was mainly static websites owned by companies, and there was close to zero interaction between users – individuals seldom produced content – leading to it being known as the read-only web.

    (2) Web 2.0: Read-Write (2004-now)

    • The Web 2.0 period began in 2004 with the emergence of social media platforms.
    • Instead of a read-only, the web evolved to be read-write.
    • Instead of companies providing content to users, they also began to provide platforms to share user-generated content and engage in user-to-user interactions.
    • As more people came online, a handful of top companies began to control a disproportionate amount of the traffic and value generated on the web.
    • Web 2.0 also birthed the advertising-driven revenue model.
    • While users could create content, they didn’t own it or benefit from its monetization.

    How is Web3 prospected to be?

    • The premise of ‘Web 3.0’ was coined by Ethereum co-founder Gavin Wood shortly after Ethereum launched in 2014.
    • Gavin put into words a solution for a problem that many early crypto adopters felt: the Web required too much trust.
    • That is, most of the Web that people know and use today relies on trusting a handful of private companies to act in the public’s best interests.

    Core ideas of Web3

    Although it’s challenging to provide a rigid definition of what Web3 is, a few core principles guide its creation.

    • Web3 is decentralized: instead of large swathes of the internet controlled and owned by centralized entities, ownership gets distributed amongst its builders and users.
    • Web3 is permission-less: everyone has equal access to participate in Web3, and no one gets excluded.
    • Web3 has native payments: it uses cryptocurrency for spending and sending money online instead of relying on the outdated infrastructure of banks and payment processors.
    • Web3 is secure: It operates using incentives and economic mechanisms instead of relying on trusted third-parties.

    Why is Web3 important?

    • Ownership: Web3 gives you ownership of your digital assets in an unprecedented way. Web3 allows for direct ownership through non-fungible tokens (NFTs).
    • Censorship resistance: The power dynamic between platforms and content creators is massively imbalanced.
    • Decentralized autonomous organizations (DAOs): As well as owning your data in Web3, you can own the platform as a collective, using tokens that act like shares in a company.

     

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  • An Indian Pioneer of ORT

    ORT

    Context

    • In the demise of Dilip Mahalabnis on October 16 we lost a pioneering public health physician the ORS pioneer who helped save millions of lives. In 1978, a Lancet editorial termed ORS the most important medical advance in this century.

    Background

    • ORT was first introduced worldwide in the 1970s to treat millions of children suffering from severe dehydration in crisis-stricken and impoverished areas. At the time, the world’s leading general medical journal The Lancet called ORT “potentially the most important medical advance since penicillin.”
    • A Lancet editorial in 1978 termed it “potentially the most important medical advance this century”.

    Interesting story of Dilip Mahalabnis and invention of ORT

    • Mahalanabis was trained as a paediatrician and joined the Cholera Research Programme of the Johns Hopkins University Center for Medical Research and Training (JHCMRT) in Calcutta in 1966.
    • His team was treating cases of the cholera epidemic in a camp in Bangaon, West Bengal that housed 3,50,000 refugees but ran out of intravenous fluids. He thought that it would be opportune to use ORS. As no ORS packets were available, they mixed salt and sugar solution (ORS) in drums and administered it to the cholera patients in the camps.
    • The library of the JHCMRT was converted into a factory. This was not a mandated mode of treatment and at great personal risk, Mahalanabis chose to respond to the humanitarian crisis in this manner.
    • It was evident in two to three weeks’ time that not only was the therapy working but that it was possible to administer ORT through volunteers (in the absence of a sufficient number of trained workers).
    • It was subsequently analyzed that ORS reduced mortality due to cholera or acute diarrhoeal diseases in these camps from 40 per cent to 5 per cent. They coined the term “oral saline” and rest is the story.

    ORT

    What is Oral Rehydration Therapy (ORT)?

    • A fluid to correct dehydration: Oral Rehydration Therapy (ORT) entails drinking water with modest amounts of sugar and salts, specifically sodium and potassium to correct dehydration due to fluid losses from diarrhoea.
    • ORT ingredients: ORT combines three ingredients such as salts, sugars and water to quickly reverse the signs of dehydration. Through the process of osmosis, the salts and sugars pull water into your bloodstream and speed up rehydration.
    • Essential electrolytes which replenish Blood: ORT also replenishes your blood with essential electrolytes (minerals) that are lost due to intense exercise, exposure to extreme weather conditions, or diarrhea and other illnesses. Water doesn’t contain electrolytes and so, ironically, water alone cannot cure dehydration like ORT.
    • An effective electrolyte: Administration of fluids through the intravenous route used to be the mainstay of management of cholera till the results of a study demonstrated that an oral solution of glucose and electrolytes was effective for replacing water and electrolyte losses.
    • Quick and efficient: The translation of the basic science concept to quick and efficient practice was, however, not easy. And that is the fascinating story and sterling contribution of Mahalanabis and his co-workers on ORT.

    What is Dehydration?

    • Dehydration occurs when you use or lose more fluid than you take in, and your body doesn’t have enough water and other fluids to carry out its normal functions. If you don’t replace lost fluids, you will get dehydrated.

    ORT

    What is Disease Cholera?

    • Cholera is an acute diarrhoeal infection caused by ingestion of food or water contaminated with the bacterium Vibrio cholerae that can kill within hours if left untreated.
    • Most of those infected will have no or mild symptoms and can be successfully treated with oral rehydration solution. Cholera affects both children and adults.
    • Provision of safe water and sanitation is critical to prevent and control the transmission of cholera and other waterborne diseases.
    • Cholera remains a global threat to public health and an indicator of inequity and lack of social development.

    Recent outbreak of cholera In India

    • Cholera is said to be endemic in India. However, the reported cases in India tend to be much lesser than the actual numbers, say doctors and experts.
    • The number of cases is rising in India because we still lack the basic sanitation, hygiene and access to clean water in many communities,
    • The country reports nearly 20,000 to 30,000 cases of cholera every year, usually during the monsoon season of July to September.
    • Climate change adds up another layer to the cholera outbreak.

    Contribution of ORT to the world.

    • As a perfect alternative over the prevailing doctrine: ORT was in marked contrast to the then prevailing doctrine of patients being given only sips of water without food, euphemistically called “resting the stomach”, often worsening the underlying malnutrition.
    • For Diarrhoea: An estimated 54 million diarrhoeal deaths were averted by ORT alone between 1978 and 2008, such was the magnitude of its beneficial impacts. ORT for the management of severe diarrhea was developed in the latter half 1960s. WHO launched a worldwide campaign in 1978 to reduce mortality related to diarrhea, with ORT as one of the key elements.
    • For cholera: Administration of fluids through the intravenous route used to be the mainstay of management of cholera till the results of a study demonstrated that an oral solution of glucose and electrolytes was effective for replacing water and electrolyte losses
    • Cholera pandemic: This period coincided with the seventh cholera pandemic (El Tor biotype) that started in Indonesia in 1961 and spread to East Pakistan (Bangladesh) by 1963 and to India in 1964. Though experiments with ORS were underway, the WHO responded in 1970 by distributing large amounts of intravenous fluids – a move marked by high transportation costs and limited utilization on account of a shortage of a trained health workforce. The focus of the Southeast Asia Treaty Organization (SEATO), through the Cholera Research Laboratory in Dhaka, was to find a vaccine to protect the US troops from cholera attacks in Southeast Asia.
    • One solution for everyone: Athletes; people with illnesses, especially babies and toddlers; seniors; military personnel stationed in extreme climates; air travelers who lose electrolytes every time they fly: They all stand to dramatically improve their health and well-being with ORT.

    ORT

    Conclusion

    • Dilip Mahalanabis pioneered a simple and effective solution for diarrhoea that saves millions of lives which can be considered as one of the greatest contributions of Indian in medical sciences. To carry the carry legacy forward young scientists should step in.

    Mains Question

    Q. What do you Understand by Oral Rehydration Therapy? How it could be effective in tackling the yearly outbreaks of Cholera in India and the world. Discuss.

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  • What is RNA Origami?

    rna

    This newscard is an excerpt of the original article published in The Hindu.

    Note: It appears to be too much biological. And suddenly out of our ease of understanding.

    What is Ribo Nucleic Acid (RNA)?

    • RNA is an important biological macromolecule that is present in all biological cells.
    • It is principally involved in the synthesis of proteins, carrying the messenger instructions from DNA, which itself contains the genetic instructions required for the development and maintenance of life.
    • In some viruses, RNA, rather than DNA, carries genetic information.
    • The type of RNA dictates the function that this molecule will have within the cell.
    • Aside from the coding region of messenger RNA (mRNA) molecules that will be translated into proteins, other cellular RNA elements are involved in different processes.

    What are RNA Origami?

    • RNA origami is the nanoscale folding of RNA, enabling the RNA to create particular shapes to organize these molecules.
    • It is an attempt to generate complex human-made RNA-based devices.
    • They are stable in cells, interact with other biomolecules, including other RNA and proteins, and enable unique applications, particularly in the context of gene regulation.

    Why are they used?

    So far there have been two approaches in RNA origami and both attempt to regulate the production of protein.

    (1) To achieve precise control of protein production

    • Self-inhibiting protein expression cassettes were made by installing a strong binding site for the expressed protein in its own gene.
    • Afterwards, RNA origami decorated with the same protein-binding sites was expressed in large excess.
    • In this way, the RNA origami serves as a protein-sponge that sequesters proteins in the cell and allows expression of the self-inhibited protein.
    • This approach helped to regulate several proteins simultaneously and turn on enzymatic pathways for improved product yields.

    (2) Using for gene editing

    • The RNA origamis were integrated in the small RNAs that guide CRISPR-Cas9 enzyme to target specific sequences in the DNA genome.
    • Its scaffolds were decorated with protein-binding sites capable of recruiting transcription factors.
    • By targeting the RNA scaffolds to promoter regions, the transcription factors activated gene expression.
    • Researchers have shown that the expression strength can be tuned by the orienting the scaffold and level of transcription factors recruited.
    • These multi-enzyme pathways could be controlled for high-yield production of the anti-cancer drug violacein.

     

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  • Black Hole, Resolving the Mistry

    Black Hole

    Context

    • For the very first time, scientists noted that this observation of the Laser Interferometer Gravitational Wave (LIGO) observatories coincided with the measurements made by other telescopes that measured visual and electromagnetic signals.

    What is Black hole?

    • A black hole is a place in space where gravity pulls so much that even light can not get out. The gravity is so strong because matter has been squeezed into a tiny space. This can happen when a star is dying.
    • Because no light can get out, people can’t see black holes. They are invisible. Space telescopes with special tools can help find black holes. The special tools can see how stars that are very close to black holes act differently than other stars.

    Black Hole

    What is the background?

    • LIGO Observations: In 2017, astrophysicists observed an unusual feat among the stars. The Laser Interferometer Gravitational Wave(LIGO)observatories recorded a signal which indicated that two massive and dense stellar bodies had merged to form a third body, likely a black hole.
    • Generation gravitational waves: In the process they gave off vibrations that quite literally shook the universe and its very fabric of space time.
    • Neutron stars: Scientists, piecing together evidence from complementary measurements, surmised that the event they had observed was of two neutron stars merging and forming a black hole and, in the process, giving off light.

    Black Hole

    What are the observations through telescopes?

    • The matter moving faster than light: An unusual jet of matter was observed that gave an illusion of travelling faster than light. These were all exciting phenomena observed for the very first time by telescopes and observatories.
    • Confirmation by Hubble Space Telescope: Now, using data that had been recorded by the Global astro metric Interferometer for Astrophysics (GAIA) spacecraft and Hubble Space Telescope instruments, scientists have confirmed that the above picture is correct. They have made it more precise and descriptive.
    • Seven times the speed of light: In a paper published in Nature, they describe measuring the “apparent speed” of the jet to be about seven times the speed of light.
    • Lorenz factor: They have also measured more accurately a factor called the Lorenz factor which scales with the actual speed of the particles in the jet. Unlike earlier estimates which placed this factor at about 4, the present paper estimates this factor to be over 40. This is because they measure the speed of the relativistic jet to be close to 0.9997c, where “c” is the speed of light.
    • Clarity about the source as neutron star in block hole generation: This resolves the earlier fuzziness about what the source was and puts the source clearly as massive neutron stars merging to give a black hole and throwing off relativistic jets of particles in the process.

    Black Hole

    Merging of Neutron stars

    • Born out of Supernova explosion: Neutron stars are stellar corpses, left behind after a star has undergone a supernova explosion and reached the end of its lifetime. They are extremely dense, containing more mass than the sun in a sphere that is a few tens of kilometre wide.
    • Produces fast moving material: This has been seen in many active galactic nuclei  galaxy centres that harbour black holes and binary star systems within our galaxy, where one of the stars is a black hole. “Mostly, black holes are responsible for producing such fast moving material

    Why present observations about black Hole are significant?

    • Estimating changing position of sky: The present measurements and observations made with GAIA data are extremely challenging. They amount to measuring the position of an object in sky coordinates. These authors measured a change in sky position one millionth the span of the full moon. Normally, if one were making these measurements from earth-based telescopes, it would require data from radio telescopes spaced apart by intercontinental distances.
    • VLBI technique: This technique is called Very Long Baseline Interferometry (VLBI) and was used in the earlier papers. “Here, the authors could beat VLBI in precision because they calibrated Hubble Space Telescope data with GAIA, which is a precision astrometry mission.
    • It’s an estimate not a measurement: the researchers used both their Hubble Space Telescope and GAIA optical position measurement along with the earlier VLBI position measurement to get a better estimate of the speed of the source and angle (viewing angle) with which it is travelling with respect to us on earth. This estimate requires plugging in equations of the special theory of relativity. “So, it is an estimate as opposed to a measurement.
    • Improvement in estimation: we have learnt that neutron star mergers can result in material moving with speeds as high as 0.9997c.Earlier results using Very Long Baseline Interferometry had pegged this value at about 0.938c. with the new results this lower limit has been improved. Even earlier, with VLBI, it was understood that it was a neutron star merger that produced such ultra-relativistic material. Before the VLBI results, there were several models that could replicate the observations.
    • Explanation using ultra realistic material: The observations could be explained both by ultra-relativistic material and non relativistic material, with some differences in assumptions. That study indicated that the observed gamma ray bursts were produced along with the ultra-relativistic material.

    Conclusion

    • Current discovery strengthens the hypothesis that such neutron star mergers are responsible for a class of gamma ray bursts. Gamma ray bursts are flashes of extreme gamma ray photons that release a huge amount of energy nearly 1047 They come from different galaxies in the universe and are observed here quite frequently.

    Mains Question

    Q. What is the neutron star and how the merger of two stars produces a black hole? How LIGO and Hubble space telescope are useful in demystifying the black Hole phenomenon?

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  • The illusion of being faster than light: how a star problem was solved

    light

    Scientists have spotted something that appeared to be moving 7 times faster than the Speed of Light in a supernova like event.

    What is the news?

    • In 2017, astrophysicists observed an unusual feat among the stars.
    • The Laser Interferometer Gravitational-Wave (LIGO) observatories recorded a signal which indicated that two massive and dense stellar bodies had merged to form a third body, likely a black hole.
    • An unusual jet of matter was observed that gave an illusion of travelling faster than light.

    Can matter move faster than Light?

    • From the data, it appeared the jets of matter were moving seven times faster than light.
    • The researchers explain the reason behind the discrepancy is due to something called superluminal motion.
    • Since the jet of matter reaches Earth at the speed of light, the light it emits at later points has a relatively shorter distance, making it appear faster than it actually is.
    • After more calculations, astronomers found the real speed to be at least 99.7 percent of the speed of light (3 × 10^8 m / s).

    Crossing the speed of light: An illusion

    • The data of same incident has been recorded by the Global Astrometric Interferometer for Astrophysics (GAIA) spacecraft and Hubble (James Web) Space Telescope
    • Using it, scientists confirmed that the above picture is correct.

    How to assess it?

    • Scientists have also measured more accurately a factor called the Lorenz factor which scales with the actual speed of the particles in the jet.
    • Unlike earlier estimates which placed this factor at about 4, the present paper estimates this factor to be over 40.
    • This is because they measure the speed of the relativistic jet to be close to 9997c, where “c” is the speed of light.

    How are they observed?

    • Source is clearly as massive neutron stars merging to give a black hole and throwing off relativistic jets of particles in the process.

    Merging neutron stars: Faking to cross speed of light

    • Neutron stars are stellar corpses, left behind after a star has undergone a supernova explosion and reached the end of its lifetime.
    • They are extremely dense, containing more mass than the sun in a sphere that is a few tens of kilometre wide.
    • The observation of particles moving at seven times the speed of light is an illusion.
    • This happens in cases where a source moves (towards us) with a velocity that is very close to light’s velocity.
    • This has been seen in many active galactic nuclei — galaxy centres that harbour black holes — and binary star systems within our galaxy, where one of the stars is a black hole.
    • Mostly, black holes are responsible for producing such fast-moving material.

    How is this illusion created?

    • Normally, if one were making these measurements from earth-based telescopes, it would require data from radio telescopes spaced apart by intercontinental distances.
    • This technique is called Very Long Baseline Interferometry (VLBI) and was used in the earlier papers.

    Significance of this study

    • The significance of the paper is that now, we have learnt that neutron star mergers can result in material moving with speeds as high as 0.9997c.
    • Earlier results using Very Long Baseline Interferometry had pegged this value at about 0.938c.
    • And with the new results this lower limit has been improved.
    • Even earlier, with VLBI, it was understood that it was a neutron-star merger that produced such ultra-relativistic material.

     

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