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DOWNSIZING. “Observational studies have revealed a ‘downsizing’ trend in black hole (BH) growth: the number densities of luminous active galactic nuclei (AGN) peak at higher redshifts than those of faint AGN. This would seem to imply that massive BHs formed before low-mass BHs, in apparent contradiction to hierarchical clustering scenarios.” https://lnkd.in/d9JV8md View in LinkedIn

WE START a new paper on the Origin of the antihierarchical growth of black holes, by an international group of collaborators. These important observations about black holes will conclude this lengthy section of black holes and we will transition into how black hokes make white holes, and their properties. https://lnkd.in/d9JV8md View in LinkedIn

JACOB D. BEKENSTEIN has contributed to the foundation of black hole thermodynamics and to other aspects of the connections between information and gravitation. He is Polak Professor of Theoretical Physics at the Hebrew University of Jerusalem, a member of the Israel Academy of Sciences and Humanities, and a recipient of the Rothschild and the Israel prizes. Bekenstein dedicates this article to John Archibald Wheeler (his Ph.D. supervisor 30 years ago). https://lnkd.in/draqjTW View in LinkedIn

Hazy days of summer with high contrasts of light and shadow, blazing heat and relief. View in LinkedIn

GOD IS A GEOMETER. “Tool-use, with its Subject (the tool), Verb (movement of the tool), and Object (the workpiece), and manipulation of mental images, is an extension of the sentence. The sense of truth and falsity shares a common source with the right and wrong answers of arithmetic.” (The human mind’s origins in geometry, an unusual viewpoint) https://lnkd.in/drepKdh View in LinkedIn

THE WORLD AS INFO. “Holography may be a guide to a better theory. What is the fundamental theory like? The chain of reasoning involving holography suggests to some, notably Lee Smolin of the Perimeter Institute for Theoretical Physics in Waterloo, Ontario, that such a final theory must be concerned not with fields, not even with spacetime, but rather with information exchange among physical processes. If so, the vision of information as the stuff the world is made of will have found a worthy embodiment.” https://lnkd.in/draqjTW View in LinkedIn

CORRELATIONS. “All of these studies in the hard and soft X-ray range find that the cosmic evolution of AGN is strongly dependent on the AGN luminosity: the number density of successively less luminous AGN peaks at lower redshifts, with the lowest luminosity AGN showing a basically constant number density.” (AGN = active galactic nuclei). https://lnkd.in/d9JV8md View in LinkedIn

RARE BLACK HOLES. “More recently, it was discovered that very massive black holes (BH; 10(9) M⊙) appears to exist already at z ∼ 6 and higher, but they are extremely rare, in accordance with this trend.” (BH = black hole; z = redshift). https://lnkd.in/d9JV8md View in LinkedIn

THE CURVE. “It has been known since early optical quasar surveys that the comoving number density of luminous quasars has a pronounced peak at a redshift around z = 2–2.5, with a fairly steep decline at higher and lower redshift.” https://lnkd.in/d9JV8md View in LinkedIn