News Analysis India

Tag: Indian scientists

  • Indian scientists on team which found 80 star explosions

    Express News Service
    BENGALURU: An international team, including Indian scientists, have discovered 80 new explosions of stars – called supernova remnants (SNRs) – in the Milky Way galaxy, revealing previously unseen signatures to provide more clarity on how stars form and die. This had largely remained a mystery to astronomers and astrophysicists.An explosion of a star, resulting in an SNR, is followed by an expanding shock wave consisting of ejected material that travels through interstellar space.

    These include heavy elements and accelerated cosmic rays, which have been detected, claiming “unprecedented sensitivity and details”, by the international team that includes scientists from the Bengaluru-based Indian Institute of Science (IISc) and Indian Space Research Organisation (ISRO)-established Indian Institute of Space Science and Technology (IIST) in Thiruvananthapuram, Kerala.

    Previous surveys by various other teams had so far detected 270 SNRs, all of them observed by the radio emissions through the interstellar space. But there are an estimated 1,000 SNRs in the Milky Way, which means at least over 700-odd such SNRs continue to evade detection. 

    ‘Important step towards space research’

    Prof Nirupam Roy, Assistant Professor, Department of Physics, IISc, Prof Jagadheep D Pandian, Associate Professor, Department of Earth and Space Sciences, IIST, and Rohit Dokara, PhD student at MPIfR and originally from IISc, who is the first author of one of the series of papers on the detection of new SNRs, published in the journal Astronomy & Astrophysics, are the Indian scientists under the Global View on Star formation in the Milky Way (GLOSTAR) project.

    The GLOSTAR project used two powerful radio telescopes to scout the galaxy and detect the SNRs – the Karl G Jansky Very Large Array (VLA) telescope at the National Radio Astronomy Observatory (NRAO), USA, and the Effelsberg 100-m radio telescope, operated by the Max Planck Institute for Radio Astronomy (MPIfR), Germany, under the GLOSTAR project. 

    “Since the GLOSTAR survey detects a wide range of radio emission – from methanol molecules to ionised hydrogen – it is able to probe the formation of massive stars from very early to relatively late stages, which is important to get a complete picture of star formation in the Milky Way,” said Pandian, who has previously worked at MPIfR. Interestingly, all 80 new SNRs have been detected through the VLA data alone, although more are expected to be identified from the combined MPIfR’s Effelsberg radio telescope and the VLA data, an IISc dispatch said.

    The Effelsberg radio telescope is capable of detecting large-scale star structures, while the VLA is a collection of small antennas that can capture details at high resolution. The data pooled from both telescopes helped the researchers paint a more comprehensive picture of different astrophysical objects in the Milky Way galaxy, explained Andreas Brunthaler of MPIfR, project leader and first author of the survey’s overview paper.“This is an important step to solve this long-standing mystery of the missing supernova remnants,” said Rohit Dokara.

    The team was also able to confirm the presence of 77 previously discovered SNRs and reclassify a few that were found to be misidentified. The team was also able to detect dense pockets of ionised hydrogen, another tell-tale sign of the presence of massive young stars. The researchers detected traces of star formation, including radio emission from methanol molecules in a relatively nearby large star-forming complex called Cygnus X, about 4,600 light years from the Sun. Astrophysicists said such emissions are typical from massive stars in the very early stages of formation.

    “As visible light gets absorbed in this dense cloud around stars, most of the optical telescopes don’t reveal much. What people look for, instead, are radio emissions,” said Prof Roy.  This feat is being touted as impressive, considering that the northern telescopes used in the GLOSTAR project are able to see only half of the inner regions of the Milky Way as the project does not have such powerful telescopes in the Earth’s southern hemisphere.Apart from the three Indian scientists, other members of the team were from MPIfR and NRAO, besides collaborators from institutions in the UK, South Africa, Mexico, France and Australia.

  • Four Indian scientists challenge Big Bang Theory

    Express News Service
    BENGALURU: In what could dramatically change the way astrophysicists look at the birth of the Universe, four Indian scientists, including one from Bengaluru, have challenged the Big Bang theory related to its origin.The theory holds that the Universe was born out of a highly compressed, dense and microscopic point (called singularity) which exploded with a huge force some 13.8 billion years ago, resulting in everything arising from that singularity moving outwards in all directions. From this, all cosmic matter (as we know it today) was formed at different stages through time until now.

    The Big Bang theory was based on observation of the ‘red shift’ in the light spectrum. The light wavelength emitted from an astronomical object that is moving away from us exhibits a shift in the light spectrum (VIBGYOR) towards the red end. The Big Bang theory is supported by the understanding that the shift of light towards the red band in the spectrum is continuous and uniform in nature — an indication of all matter (galaxies and all cosmic matter) moving outwards steadily, but at great speed. Working the outward movement backwards, it would mean that it all began from a single starting point in the centre of the Universe (singularity), which is how the Big Bang theory was popularised among astrophysicists. 

    But now, in a research paper published recently in the prestigious international journal Astronomy & Astrophysics, Prof Sisir Roy from the National Institute of Advanced Studies (NIAS), Bengaluru; Arindam Mal from the Indian Space Research Organisation (ISRO), Ahmedabad; and Sarbani Palit and Ujjwal Bhattacharya from the Indian Statistical Institute (ISI), Kolkata, have revealed findings contrary to the continuous and uniform nature of movement of light towards the red band of light in the spectrum — casting doubts and challenging the Big Bang theory itself.

    Big Bang bust? Scientists present robust data 

    The researchers have found that the red shift does not occur in a uniform manner, but in recurring stages, what they refer to as periodicity in red shift.“The red shift in astronomical observation is attributed to the expanding model of the universe. One such popular model is the Big Bang model. As the change in wavelength is happening due to the expansion of the universe, the red shifts are supposed to be continuous and uniform in nature. On the contrary, our rigorous analysis of the data from Sloan Digital Sky Survey (SDSS)DR12 showed the existence of periodicity of red shifts of galaxy and quasar,” Prof Roy told TNIE.

    The Indian astrophysicists used a technique called singular value decomposition method, as against the standard spectral estimation approach that was used in discovering the uniform red shift that supports Big Bang theory. “The superiority of the singular value decomposition method in analysing red shift periodicity, especially from the point of view of robustness, is demonstrated through the simulations. We took very large data samples and used a statistical method, which is more robust than the method usually dealt with by astronomers,” Prof Roy said.

    Interestingly, although this is not the first time that the Big Bang theory has been challenged, the previous challenges were based on much smaller sample sizes. The Steady State Theory, Gravitational Lending Model, Tired Photon Hypothesis, Variable Mass Hypothesis have all challenged the Big Bang theory in the past.“But the problem with each of them was the sample size. The renowned physicist, late Stephen Hawking, and his collaborators had stated that the criticism levelled against the theories challenging the Big Bang is because the samples of red shifts that were analysed were rather small and selected in a heterogeneous manner, which made it hard to assess their significance,” Prof Roy said.

    The latest findings by the astrophysicists is also found to be compatible with the Fred Hoyle-Jayant Narlikar variable mass theory which hypothesized that quasars are born in and ejected from the nuclei of parent galaxies as massless objects and the particle masses in them systematically increase with epoch. “Our findings may support some alternate models like Hoyle-Narlikar variable mass theory on the existence of periodicity of red shifts. Their idea is shown to be compatible with the empirical observations on periodicity of red shifts,” Prof Roy said.

    In 1973, astronomer William G Tifft was the first to report the non-uniform nature of the red shifts, or the periodicity of red shifts. Subsequently, several astrophysicists, including India’s world-renowned Prof Jayant Narlikar, analysed the data and claimed that such periodicity of red shift for galaxy and quasar exists. 

  • PM adds Jai Anusandhan to Jai jawan, Jai kisan and Jai Vigyan

    Prime Minister Narendra Modi Thursday added Jai Anusandhan to former prime minister Lal Bahadur Shastri’s famous slogan of Jai Jawan, Jai Kisan and Atal Bihari Vajpayee’s Jai Vigyan.

    He was speaking on Future India: Science and Technology at the 106th Indian Science Congress in Jalandhar.

    The prime minister said the life and works of Indian scientists are a compelling testament of integration of deep fundamental insights with technology development and nation-building.

    “Today’s new slogan is Jai Jawan, Jai Kisan, Jai Vigyan and Jai Anusandhan. I would like to add Jai Anusandhan to it,” he said.

    He further said that it was through science that India was transforming its present and working to secure its future.

    “2018 was a good year for Indian science. Among our achievements this year are the production of aviation grade biofuel, Divya Nayan — a machine for visually impaired, inexpensive devices for diagnosis of cervical cancer, TB, dengue. A real-time landslide warning system,” he said.