Since the estimated energy output for GRB971214 is Q_gamma ~3 times 1053ergs in soft gamma-rays alone, it is conceivable that the actual energy output in the preceding neutrino burst is higher by two orders, i.e, Q_nu... more abstractSince the estimated energy output for GRB971214 is Q_gamma ~3 times 1053ergs in soft gamma-rays alone, it is conceivable that the actual energy output in the preceding neutrino burst is higher by two orders, i.e, Q_nu ~1055 ergs (Mitra, A & A, in press, astro-ph / 9807197). We propose that such an energy liberation is easily explained by considering gravitational

Gravitational Collapse, Gamma Ray Burst, and Gamma Ray

ABSTRACT

General Theory of Relativity

Dust (Astronomy & Astrophysics), Magnetic field, Gamma Ray Burst, and Gamma Ray

Publication Name: Astronomy and Astrophysics

Dust (Astronomy & Astrophysics)

Publication Name: Astronomy and Astrophysics

Cosmology and Gravitation

Publication Name: Gravitation and Cosmology

My last Physics Colloquium in BARC, delivered on December 02, 2011. Though its ppt is skeletal as I mostly talk extempore, I am uploading it as some friends have wanted me to do so.

Physics, Theoretical Physics, Cosmology (Physics), Particle Physics, General Relativity, and 4 more

Physics, Cosmology (Physics), Science Education, General Relativity, History of Science, and 6 more

Physics, Cosmology (Physics), Particle Physics, General Relativity, Astrophysics, and 1 more

Event Date: Nov 26, 2013

Organization: Invited Talk in National Symposium on VHE Gamma Ray Astronomy, BARC-TIFR, Mumbai, India

Plenary Talk in XXIX-th International Workshop on High Energy Physics “NEW RESULTS & ACTUAL PROBLEMS in PARTICLE & ASTROPARTICLE PHYSICS & COSMOLOGY”, June 26-28, 2013, in Protvino, Russia

Physics, Cosmology (Physics), General Relativity, Astrophysics, and Astronomy

"Plenary Talk in XXIX-th International Workshop on High Energy Physics “NEW RESULTS & ACTUAL PROBLEMS in PARTICLE & ASTROPARTICLE PHYSICS & COSMOLOGY”, June 26-28, 2013, in Protvino, Russia

Physics, High Energy Astrophysics, Gravitation, General Relativity, Active Galactic Nuclei, and 5 more

Physics, Theoretical Physics, Cosmology (Physics), General Relativity, Astrophysics, and 1 more

Organization: International Symposium on Experimental Gravitation January 5th - 9th 2009 Riviera Suites and Conference Centre, , India Tata Institute of Fundamental Research, Mumbai, India

—The results of several cosmographic tests of the standard ΛCDM model taking into account evolution and a " tired-light " model without evolution are compared. Physical tests and observations of the microwave backgrou... more abstract—The results of several cosmographic tests of the standard ΛCDM model taking into account evolution and a " tired-light " model without evolution are compared. Physical tests and observations of the microwave background are also considered. Arguments supporting each of these models are presented. The general conclusion is that it is not possible to unambiguously identify a preferred cosmological model based on the currently available observational data. The nature of the redshift of spectral lines emitted by extragalactic objects is discussed. Possibilities for further studies are also briefly noted.

Physics, Cosmology (Physics), General Relativity, Astrophysics, and Astronomy

Physics, Quantum Gravity, General Relativity, and Astrophysics

Physics, Quantum Gravity, General Relativity, and Astrophysics

Physics, Quantum Gravity, Particle Physics, General Relativity, and Quantum Mechanics

Physics, Quantum Gravity, Astrophysics, and Astronomy

Physics, Quantum Gravity, General Relativity, Astrophysics, and Astronomy

Physics, Quantum Gravity, General Relativity, Astrophysics, and Astronomy

Problems of scientific cosmology only rarely occur in the works of Karl Popper. Nevertheless, it was a subject that interested him and which he occasionally commented on. What is more important, his general claim of f... more abstractProblems of scientific cosmology only rarely occur in the works of Karl Popper. Nevertheless, it was a subject that interested him and which he occasionally commented on. What is more important, his general claim of falsifiability as a criterion that demarcates science from non-science has played a significant role in periods of the development of modern physical cosmology. The paper examines the historical contexts of the interaction between cosmology and Popperian philosophy of science. Apart from covering Popper’s inspiration from Einstein and his views on questions of cosmology, it focuses on the impact of his thoughts in two periods of controversy of modern cosmology, the one related to the steady state theory and the other to the recent multiverse proposal. It turns out that the impact has been considerable, and continues to be so, but also that the versions of Popperian methodology discussed by cosmologists are sometimes far from what Popper actually thought and wrote.

Physics, Cosmology (Physics), Particle Physics, General Relativity, History of Physics, and 2 more

Social Sciences, History of Science, and Political Science

Australian National University astronomer Professor Brian Schmidt is a Nobel Laureate for physics. On Monday the 15th of September 2014 he appeared on the ABC national Australian television programme Q&A. His response... more abstractAustralian National University astronomer Professor Brian Schmidt is a Nobel Laureate for physics. On Monday the 15th of September 2014 he appeared on the ABC national Australian television programme Q&A. His response to a question put to him by an eleven year old boy in the audience is a typical example of why it is very unwise to passively accept the word of an Authority. Presented here are a number of the nonsensical claims made by a Nobel Laureate on matters of cosmology and mathematics; symptomatic of just how intellectually decrepit astronomy and astrophysics have become.

Physics, Cosmology (Physics), Particle Physics, Physics Education, Astrophysics, and 2 more

The research paper entitled, “Sources of stellar energy Einstein – Eddington timescale of gravitational contraction and eternally collapsing objects”, authored by Dr. A. Mitra of Astrophysical Sciences Division has be... more abstractThe research paper entitled, “Sources of stellar energy Einstein – Eddington timescale of gravitational contraction and eternally collapsing objects”, authored by Dr. A. Mitra of Astrophysical Sciences Division has been selected as a Highlight Paper of the Max Planck Society of Germany for the year 2006.

History of Science and Technology, Physics, Cosmology (Physics), General Relativity, Astrophysics, and 2 more

In 1999, Physics World surveyed approximately 130 physicists and asked them to name the five researchers who made the most important contributions to the field. Albert Einstein came first with 119 votes. Richard Feynm... more abstractIn 1999, Physics World surveyed approximately 130 physicists and asked them to name the five researchers who made the most important contributions to the field. Albert Einstein came first with 119 votes. Richard Feynman came seventh with 23 votes. Paul Dirac came eighth with 22 votes. Hawking received one vote. Throughout his career, he and his publishers have demonstrated a keen understanding of the dynamics of publicity. Other physicists have been, at times, ambivalent about his reputation, because of what some of them see as his having a public profile that is out of proportion to his scientific merit.

Physics, Philosophy of Science, Cosmology (Physics), Quantum Gravity, General Relativity, and 5 more

This IAU Bulletin highlights a news report published in ``The Daily Galaxy '' suggesting that the so-called ``Black Holes'' could be ``Eternally Collapsing Objects'' (Ultra-compact, ultra-hot balls of plasma/fire)

Physics, General Relativity, History of Physics, Physics Education, Astrophysics, and 2 more

Physics, Cosmology (Physics), General Relativity, History of Science, History of Astronomy, and 3 more

Physics, Theoretical Physics, Quantum Physics, General Relativity, Theoretical astrophysics, and 3 more

Physics, Theoretical Physics, General Relativity, Theoretical astrophysics, Black Holes, and 2 more

Physics, Theoretical Physics, High Energy Astrophysics, Gravitation, General Relativity, and 4 more

Physics, Cosmology (Physics), General Relativity, Astrophysics, Astronomy, and 1 more

Cosmology (Physics), General Relativity, History of Science, History of Physics, Physics Education, and 2 more

Social Sciences, History of Science, and History of Physics

Physics, Cosmology (Physics), Science Education, General Relativity, History of Science, and 4 more

Physics, Cosmology (Physics), General Relativity, History of Science, History of Physics, and 3 more

Physics, Cosmology (Physics), General Relativity, Astrophysics, and Astronomy

Quantum Computing, Physics, Foundations of Quantum Mechanics, Quantum Mechanics, and Physics Education/Science Education

Physics, General Relativity, History of Science, History of Physics, Astrophysics, and 1 more

History of Science, History of Physics, and Physics Education

Physics, Cosmology (Physics), Particle Physics, General Relativity, History of Science, and 4 more

Physics, Cosmology (Physics), General Relativity, History of Science, History of Physics, and 2 more

It turns out that a brilliant Indian physicist by the name of Abhas Mitra has solved the puzzle. Reexamining the equations for black holes, Mitra discovered that you can indeed create a singularity with an event horiz... more abstractIt turns out that a brilliant Indian physicist by the name of Abhas Mitra has solved the puzzle. Reexamining the equations for black holes, Mitra discovered that you can indeed create a singularity with an event horizon surrounding it. The trouble is, you can only do this if the black hole's mass is zero! In other words, even though you can plug any large mass you want into an equation on the blackboard, you can't have a black hole with mass in reality. So with a proper understanding of general relativity, we see that there's no such thing as an event horizon surrounding a singularity (naked or otherwise), no Hawking radiation, and no information-loss paradox. Problem solved. See how Nature always elegantly intervenes to invalidate our flights of fancy that might violate Her fundamental principles? There is no need for quantum wormhole entanglements, à la Susskind, or nasty AMPS firewalls because there is no way of making a black hole in the first place. Predictably, the physics community is not enamored with Mitra's ideas. After all, scientists have spent almost 100 years contemplating black holes and basing really cool and radical theories on them. But recent astronomical data on so-called black hole candidates (BHCs) show they have stupendously large magnetic fields, which classic black holes simply cannot have. So it looks like Mitra is right. Even the legendary Stephen Hawking himself recently cast doubts on the existence of black holes, and has started calling them gray holes instead. Unfortunately, the absence of black holes is bad news for many current cosmological theories, especially ones like Lee Smolin's evolving universes, where mommy universes give birth to black holes that collapse into baby universes; a kind of genetic selection process that results in universes with lots of black holes and high probabilities of being friendly to intelligent life based on the anthropic principle

Physics, Cosmology (Physics), Particle Physics, General Relativity, History of Science, and 3 more

`The astrophysicist named Abhas Mitra came to exactly the same conclusion that M = 0, but in a much more formal and elegant way. A number of people have reviewed Mitra's papers, and nobody has found any mathematical e... more abstract`The astrophysicist named Abhas Mitra came to exactly the same conclusion that M = 0, but in a much more formal and elegant way. A number of people have reviewed Mitra's papers, and nobody has found any mathematical errors in them. So the conclusion is inescapable: The only true black holes that can exist are ones with zero mass. This doesn't mean that there are no very large astronomical objects that look a lot like black holes when viewed from far away. It simply means that they don't have external Event Horizons. Mitra calls them eternally-collapsing objects (ECOs). The problem is that the black hole candidates astrophysicists identify almost always HAVE ENORMOUS MAGNETIC FIELD – larger than any other magnetic fields in the universe. Some may argue that those magnetic fields originate outside their Event Horizons from matter spinning into them, but THAT ARGUMENT SEEMS SHAKY.. On the other hand, there is nothing that would prevent ECOs from having an ARBITRARILY STRONG MAGNETIC FIELDS because they don't have Event Horizons.

Physics, Philosophy of Science, Cosmology (Physics), Particle Physics, General Relativity, and 4 more

The energy released in the synthesis of cosmic He from hydrogen is almost exactly equal to the energy 4 contained in the cosmic microwave background radiation. This result strongly suggests that the He was produced 4 ... more abstractThe energy released in the synthesis of cosmic He from hydrogen is almost exactly equal to the energy 4 contained in the cosmic microwave background radiation. This result strongly suggests that the He was produced 4 by hydrogen burning in stars and not in the early stages of a big bang. In addition, we show that there are good arguments for believing that the other light isotopes, D, He, Li, Li, Be, B, and B, were also synthesized 3 6 7 9 10 11 in processes involving stars. By combining these results with the earlier, much more detailed work of Burbidge et al. and of Cameron, we can finally conclude that all of the chemical elements were synthesized from hydrogen in stars over a time of about 10 11 yr. Subject headings: cosmic microwave background — early universe — nuclear reactions, nucleosynthesis, abundances

Physics, Cosmology (Physics), Particle Physics, Astrophysics, and Astronomy

Physics, Stellar Astrophysics, Cosmology (Physics), Theoretical astrophysics, Astrophysics, and 2 more

Physics, History of Science, Astrophysics, and Astronomy