Exploring Black Holes with Chandra X-Ray Observatory with Its Unique Properties, Chandra Is Peerless As a Black Hole Probe - Both Near and Far
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
A Mathematical Derivation of the General Relativistic Schwarzschild
A Mathematical Derivation of the General Relativistic Schwarzschild Metric An Honors thesis presented to the faculty of the Departments of Physics and Mathematics East Tennessee State University In partial fulfillment of the requirements for the Honors Scholar and Honors-in-Discipline Programs for a Bachelor of Science in Physics and Mathematics by David Simpson April 2007 Robert Gardner, Ph.D. Mark Giroux, Ph.D. Keywords: differential geometry, general relativity, Schwarzschild metric, black holes ABSTRACT The Mathematical Derivation of the General Relativistic Schwarzschild Metric by David Simpson We briefly discuss some underlying principles of special and general relativity with the focus on a more geometric interpretation. We outline Einstein’s Equations which describes the geometry of spacetime due to the influence of mass, and from there derive the Schwarzschild metric. The metric relies on the curvature of spacetime to provide a means of measuring invariant spacetime intervals around an isolated, static, and spherically symmetric mass M, which could represent a star or a black hole. In the derivation, we suggest a concise mathematical line of reasoning to evaluate the large number of cumbersome equations involved which was not found elsewhere in our survey of the literature. 2 CONTENTS ABSTRACT ................................. 2 1 Introduction to Relativity ...................... 4 1.1 Minkowski Space ....................... 6 1.2 What is a black hole? ..................... 11 1.3 Geodesics and Christoffel Symbols ............. 14 2 Einstein’s Field Equations and Requirements for a Solution .17 2.1 Einstein’s Field Equations .................. 20 3 Derivation of the Schwarzschild Metric .............. 21 3.1 Evaluation of the Christoffel Symbols .......... 25 3.2 Ricci Tensor Components ................. -
Stephen Hawking: 'There Are No Black Holes' Notion of an 'Event Horizon', from Which Nothing Can Escape, Is Incompatible with Quantum Theory, Physicist Claims
NATURE | NEWS Stephen Hawking: 'There are no black holes' Notion of an 'event horizon', from which nothing can escape, is incompatible with quantum theory, physicist claims. Zeeya Merali 24 January 2014 Artist's impression VICTOR HABBICK VISIONS/SPL/Getty The defining characteristic of a black hole may have to give, if the two pillars of modern physics — general relativity and quantum theory — are both correct. Most physicists foolhardy enough to write a paper claiming that “there are no black holes” — at least not in the sense we usually imagine — would probably be dismissed as cranks. But when the call to redefine these cosmic crunchers comes from Stephen Hawking, it’s worth taking notice. In a paper posted online, the physicist, based at the University of Cambridge, UK, and one of the creators of modern black-hole theory, does away with the notion of an event horizon, the invisible boundary thought to shroud every black hole, beyond which nothing, not even light, can escape. In its stead, Hawking’s radical proposal is a much more benign “apparent horizon”, “There is no escape from which only temporarily holds matter and energy prisoner before eventually a black hole in classical releasing them, albeit in a more garbled form. theory, but quantum theory enables energy “There is no escape from a black hole in classical theory,” Hawking told Nature. Peter van den Berg/Photoshot and information to Quantum theory, however, “enables energy and information to escape from a escape.” black hole”. A full explanation of the process, the physicist admits, would require a theory that successfully merges gravity with the other fundamental forces of nature. -
Black Holes. the Universe. Today’S Lecture
Physics 311 General Relativity Lecture 18: Black holes. The Universe. Today’s lecture: • Schwarzschild metric: discontinuity and singularity • Discontinuity: the event horizon • Singularity: where all matter falls • Spinning black holes •The Universe – its origin, history and fate Schwarzschild metric – a vacuum solution • Recall that we got Schwarzschild metric as a solution of Einstein field equation in vacuum – outside a spherically-symmetric, non-rotating massive body. This metric does not apply inside the mass. • Take the case of the Sun: radius = 695980 km. Thus, Schwarzschild metric will describe spacetime from r = 695980 km outwards. The whole region inside the Sun is unreachable. • Matter can take more compact forms: - white dwarf of the same mass as Sun would have r = 5000 km - neutron star of the same mass as Sun would be only r = 10km • We can explore more spacetime with such compact objects! White dwarf Black hole – the limit of Schwarzschild metric • As the massive object keeps getting more and more compact, it collapses into a black hole. It is not just a denser star, it is something completely different! • In a black hole, Schwarzschild metric applies all the way to r = 0, the black hole is vacuum all the way through! • The entire mass of a black hole is concentrated in the center, in the place called the singularity. Event horizon • Let’s look at the functional form of Schwarzschild metric again: ds2 = [1-(2m/r)]dt2 – [1-(2m/r)]-1dr2 - r2dθ2 -r2sin2θdφ2 • We want to study the radial dependence only, and at fixed time, i.e. we set dφ = dθ = dt = 0. -
Hawking Radiation
a brief history of andreas müller student seminar theory group max camenzind lsw heidelberg mpia & lsw january 2004 http://www.lsw.uni-heidelberg.de/users/amueller talktalk organisationorganisation basics ☺ standard knowledge advanced knowledge edge of knowledge and verifiability mindmind mapmap whatwhat isis aa blackblack hole?hole? black escape velocity c hole singularity in space-time notion „black hole“ from relativist john archibald wheeler (1968), but first speculation from geologist and astronomer john michell (1783) ☺ blackblack holesholes inin relativityrelativity solutions of the vacuum field equations of einsteins general relativity (1915) Gµν = 0 some history: schwarzschild 1916 (static, neutral) reissner-nordstrøm 1918 (static, electrically charged) kerr 1963 (rotating, neutral) kerr-newman 1965 (rotating, charged) all are petrov type-d space-times plug-in metric gµν to verify solution ;-) ☺ black hole mass hidden in (point or ring) singularity blackblack holesholes havehave nono hairhair!! schwarzschild {M} reissner-nordstrom {M,Q} kerr {M,a} kerr-newman {M,a,Q} wheeler: no-hair theorem ☺ blackblack holesholes –– schwarzschildschwarzschild vs.vs. kerrkerr ☺ blackblack holesholes –– kerrkerr inin boyerboyer--lindquistlindquist black hole mass M spin parameter a lapse function delta potential generalized radius sigma potential frame-dragging frequency cylindrical radius blackblack holehole topologytopology blackblack holehole –– characteristiccharacteristic radiiradii G = M = c = 1 blackblack holehole -- -
Scattering on Compact Body Spacetimes
Scattering on compact body spacetimes Thomas Paul Stratton A thesis submitted for the degree of Doctor of Philosophy School of Mathematics and Statistics University of Sheffield March 2020 Summary In this thesis we study the propagation of scalar and gravitational waves on compact body spacetimes. In particular, we consider spacetimes that model neutron stars, black holes, and other speculative exotic compact objects such as black holes with near horizon modifications. We focus on the behaviour of time-independent perturbations, and the scattering of plane waves. First, we consider scattering by a generic compact body. We recap the scattering theory for scalar and gravitational waves, using a metric perturbation formalism for the latter. We derive the scattering and absorption cross sections using the partial-wave approach, and discuss some approximations. The theory of this chapter is applied to specific examples in the remainder of the thesis. The next chapter is an investigation of scalar plane wave scattering by a constant density star. We compute the scattering cross section numerically, and discuss a semiclassical, high-frequency analysis, as well as a geometric optics approach. The semiclassical results are compared to the numerics, and used to gain some physical insight into the scattering cross section interference pattern. We then generalise to stellar models with a polytropic equation of state, and gravitational plane wave scattering. This entails solving the metric per- turbation problem for the interior of a star, which we accomplish numerically. We also consider the near field scattering profile for a scalar wave, and the cor- respondence to ray scattering and the formation of a downstream cusp caustic. -
Evolution of the Cosmological Horizons in a Concordance Universe
Evolution of the Cosmological Horizons in a Concordance Universe Berta Margalef–Bentabol 1 Juan Margalef–Bentabol 2;3 Jordi Cepa 1;4 [email protected] [email protected] [email protected] 1Departamento de Astrofísica, Universidad de la Laguna, E-38205 La Laguna, Tenerife, Spain: 2Facultad de Ciencias Matemáticas, Universidad Complutense de Madrid, E-28040 Madrid, Spain. 3Facultad de Ciencias Físicas, Universidad Complutense de Madrid, E-28040 Madrid, Spain. 4Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife, Spain. Abstract The particle and event horizons are widely known and studied concepts, but the study of their properties, in particular their evolution, have only been done so far considering a single state equation in a deceler- ating universe. This paper is the first of two where we study this problem from a general point of view. Specifically, this paper is devoted to the study of the evolution of these cosmological horizons in an accel- erated universe with two state equations, cosmological constant and dust. We have obtained closed-form expressions for the horizons, which have allowed us to compute their velocities in terms of their respective recession velocities that generalize the previous results for one state equation only. With the equations of state considered, it is proved that both velocities remain always positive. Keywords: Physics of the early universe – Dark energy theory – Cosmological simulations This is an author-created, un-copyedited version of an article accepted for publication in Journal of Cosmology and Astroparticle Physics. IOP Publishing Ltd/SISSA Medialab srl is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. -
A Hole in the Black Hole
Open Journal of Mathematics and Physics | Volume 2, Article 78, 2020 | ISSN: 2674-5747 https://doi.org/10.31219/osf.io/js7rf | published: 7 Feb 2020 | https://ojmp.wordpress.com DA [microresearch] Diamond Open Access A hole in the black hole Open Physics Collaboration∗† April 19, 2020 Abstract Supposedly, matter falls inside the black hole whenever it reaches its event horizon. The Planck scale, however, imposes a limit on how much matter can occupy the center of a black hole. It is shown here that the density of matter exceeds Planck density in the singularity, and as a result, spacetime tears apart. After the black hole is formed, matter flows from its center to its border due to a topological force, namely, the increase on the tear of spacetime due to its limit until it reaches back to the event horizon, generating the firewall phenomenon. We conclude that there is no spacetime inside black holes. We propose a solution to the black hole information paradox. keywords: black hole information paradox, singularity, firewall, entropy, topology, quantum gravity Introduction 1. Black holes are controversial astronomical objects [1] exhibiting such a strong gravitational field that nothing–not even light–can escape from inside it [2]. ∗All authors with their affiliations appear at the end of this paper. †Corresponding author: [email protected] | Join the Open Physics Collaboration 1 2. A black hole is formed when the density of matter exceeds the amount supported by spacetime. 3. It is believed that at or near the event horizon, there are high-energy quanta, known as the black hole firewall [3]. -
NIDUS IDEARUM. Scilogs, IV: Vinculum Vinculorum
University of New Mexico UNM Digital Repository Mathematics and Statistics Faculty and Staff Publications Academic Department Resources 2019 NIDUS IDEARUM. Scilogs, IV: vinculum vinculorum Florentin Smarandache University of New Mexico, [email protected] Follow this and additional works at: https://digitalrepository.unm.edu/math_fsp Part of the Celtic Studies Commons, Digital Humanities Commons, European Languages and Societies Commons, German Language and Literature Commons, Mathematics Commons, and the Modern Literature Commons Recommended Citation Smarandache, Florentin. "NIDUS IDEARUM. Scilogs, IV: vinculum vinculorum." (2019). https://digitalrepository.unm.edu/math_fsp/310 This Book is brought to you for free and open access by the Academic Department Resources at UNM Digital Repository. It has been accepted for inclusion in Mathematics and Statistics Faculty and Staff Publications by an authorized administrator of UNM Digital Repository. For more information, please contact [email protected], [email protected], [email protected]. scilogs, IV nidus idearum vinculum vinculorum Bipolar Neutrosophic OffSet Refined Neutrosophic Hypergraph Neutrosophic Triplet Structures Hyperspherical Neutrosophic Numbers Neutrosophic Probability Distributions Refined Neutrosophic Sentiment Classes of Neutrosophic Operators n-Valued Refined Neutrosophic Notions Theory of Possibility, Indeterminacy, and Impossibility Theory of Neutrosophic Evolution Neutrosophic World Florentin Smarandache NIDUS IDEARUM. Scilogs, IV: vinculum vinculorum Brussels, 2019 Exchanging ideas with Mohamed Abdel-Basset, Akeem Adesina A. Agboola, Mumtaz Ali, Saima Anis, Octavian Blaga, Arsham Borumand Saeid, Said Broumi, Stephen Buggie, Victor Chang, Vic Christianto, Mihaela Colhon, Cuờng Bùi Công, Aurel Conțu, S. Crothers, Otene Echewofun, Hoda Esmail, Hojjat Farahani, Erick Gonzalez, Muhammad Gulistan, Yanhui Guo, Mohammad Hamidi, Kul Hur, Tèmítópé Gbóláhàn Jaíyéolá, Young Bae Jun, Mustapha Kachchouh, W. -
Novel Shadows from the Asymmetric Thin-Shell Wormhole
Physics Letters B 811 (2020) 135930 Contents lists available at ScienceDirect Physics Letters B www.elsevier.com/locate/physletb Novel shadows from the asymmetric thin-shell wormhole ∗ Xiaobao Wang a, Peng-Cheng Li b,c, Cheng-Yong Zhang d, Minyong Guo b, a School of Applied Science, Beijing Information Science and Technology University, Beijing 100192, PR China b Center for High Energy Physics, Peking University, No. 5 Yiheyuan Rd, Beijing 100871, PR China c Department of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, No. 5 Yiheyuan Rd, Beijing 100871, PR China d Department of Physics and Siyuan Laboratory, Jinan University, Guangzhou 510632, PR China a r t i c l e i n f o a b s t r a c t Article history: For dark compact objects such as black holes or wormholes, the shadow size has long been thought to Received 29 September 2020 be determined by the unstable photon sphere (region). However, by considering the asymmetric thin- Accepted 2 November 2020 shell wormhole (ATSW) model, we find that the impact parameter of the null geodesics is discontinuous Available online 6 November 2020 through the wormhole in general and hence we identify novel shadows whose sizes are dependent of Editor: N. Lambert the photon sphere in the other side of the spacetime. The novel shadows appear in three cases: (A2) The observer’s spacetime contains a photon sphere and the mass parameter is smaller than that of the opposite side; (B1, B2) there’ s no photon sphere no matter which mass parameter is bigger. -
What Is a Black Hole?
National Aeronautics and Space Administration Can black holes be used to travel through spacetime? Where are black holes located? It’s a science fiction cliché to use black holes to travel through space. Dive into one, the story goes, Black holes are everywhere! As far as astronomers can tell, there are prob- and you can pop out somewhere else in the Universe, having traveled thousands of light years in the blink of an eye. ably millions of black holes in our Milky Way Galaxy alone. That may sound like a lot, but the nearest one discovered is still 1600 light years away — a But that’s fiction. In reality, this probably won’t work. Black holes twist space and time, in a sense punching a hole in the fabric of the pretty fair distance, about 16 quadrillion kilometers! That’s certainly too far Universe. There is a theory that if this happens, a black hole can form a tunnel in space called a wormhole (because it’s like a tunnel away to affect us. The giant black hole in the center of the Galaxy is even formed by a worm as it eats its way through an apple). If you enter a wormhole, you’ll pop out someplace else far away, not needing to farther away: at a distance of 26,000 light years, we’re in no danger of travel through the actual intervening distance. being sucked into the vortex. The neutron star companion While wormholes appear to be possible mathematically, they would be violently unstable, or need to be made of theoretical For a black hole to be dangerous, it would have to be very close, probably of a black hole spirals in and is destroyed as it merges with the forms of matter which may not occur in nature. -
The X-Ray Background and the ROSAT Deep Surveys
THE X–RAY BACKGROUND AND THE ROSAT DEEP SURVEYS G. HASINGER Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany E-mail : [email protected] G. ZAMORANI Osservatorio Astronomico, Via Zamboni 33, Bologna, 40126, Italy E-mail: [email protected] In this article we review the measurements and understanding of the X-ray back- ground (XRB), discovered by Giacconi and collaborators 35 years ago. We start from the early history and the debate whether the XRB is due to a single, homo- geneous physical process or to the summed emission of discrete sources, which was finally settled by COBE and ROSAT. We then describe in detail the progress from ROSAT deep surveys and optical identifications of the faint X-ray source popula- tion. In particular we discuss the role of active galactic nuclei (AGNs) as dominant contributors for the XRB, and argue that so far there is no need to postulate a hypothesized new population of X-ray sources. The recent advances in the under- standing of X-ray spectra of AGN is reviewed and a population synthesis model, based on the unified AGN schemes, is presented. This model is so far the most promising to explain all observational constraints. Future sensitive X-ray surveys in the harder X-ray band will be able to unambiguously test this picture. 1 Introduction It is a heavy responsibility for us, as it would be for everybody else, to write a paper on the X–ray Deep Surveys and the X–ray background (XRB) for this book, in honour of Riccardo Giacconi. -
NASA Observatory Confirms Black Hole Limits 16 February 2005
NASA Observatory Confirms Black Hole Limits 16 February 2005 than ever how super massive black holes grow." One revelation is there is a strong connection between the growth of black holes and the birth of stars. Previously, astronomers had done careful studies of the birthrate of stars in galaxies but didn't know as much about the black holes at their centers. "These galaxies lose material into their central black holes at the same time they make their stars," Barger said. "So whatever mechanism governs star formation in galaxies also governs black hole growth." Astronomers made an accurate census of both the biggest, active black holes in the distance, and the The very largest black holes reach a certain point relatively smaller, calmer ones closer to Earth. and then grow no more. That's according to the Now, for the first time, the ones in between have best survey to date of black holes made with been properly counted. NASA's Chandra X-ray Observatory. Scientists also discovered previously hidden black holes well "We need to have an accurate head count over below their weight limit. time of all growing black holes if we ever hope to understand their habits, so to speak," said co- These new results corroborate recent theoretical author Richard Mushotzky of NASA's Goddard work about how black holes and galaxies grow. Space Flight Center, Greenbelt, Md. The biggest black holes, those with at least 100 million times the mass of the sun, ate voraciously This study relied on the deepest X-ray images ever during the early universe.