10 Hot Black Hole Topics

- September 4th 2015, by Alma Ionescu

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Black holes are a hot topic in theoretical physics and the interest of the utmost experts seems to be gravitating around it. As Feynman famously said, physics has practical applications just like sex, but that’s not why people do it. This complex field needs a guide to show how the different areas of research are connected. So why do we have this major controversy around black hole physics? The hype starts with a theory of quantum gravity and the battle over quantum information.

10- The Black Hole Wars

Matter falls in a black hole and matter never comes out. At least this is what was widely believed until the end of the 90’s because black holes provide a straightforward mechanism to destroy information forever. 'The Black Hole War', written by Leonard Susskind, Felix Bloch professor of Theoretical physics at Stanford University, is a historical account of this raging war fought over the fate of matter lost inside black holes. At the beginning of the 80’s, Susskind met Stephen Hawking and the dispute began. Hawking, a general relativist, thought that since the black hole singularity was shown to annihilate whatever fell in, then so be it. This was what the theory told us and there was no point denying it. Moreover, particles couldn't avert this dire fate because of the Penrose Singularity Theorems, which say that all the paths of the infalling matter must and will encounter the central singularity in a finite time. From life and black holes no one comes out alive. Susskind, supporting the quantum mechanical point of view, claimed that information must be preserved one way or another. Things don’t just vanish from the universe. In 2008 when the book was published, it was considered that the war was over as of 2004, when Hawking conceded the bet he took on the fate of information and had to pay up by means of the famous baseball encyclopedia, “from which information can be retrieved at will.”

Special Relativity Study Materials

Light cone (Image Credit: Wikimedia Commons)

Introduction:

One of the greatest triumphs of Maxwell's electromagnetic theory (c. 1864) was the explanation of light as an electromagnetic wave. But a question arises; Waves in what? In conformity with the mechanistic view of nature then prevailing, it seemed imperative to postulate the existence of a medium—the ether—which would serve as a carrier for these waves. This led to the most urgent physical problem of the time: the detection of the earth's motion through the ether.

One of the many experiments were devised for this purpose. Michelson and Morley (1887), looked for a directional variation in the velocity of light on Earth. Fizeau (1860), Mascart (1872), and later Lord Rayleigh (1902), looked for an expected effect of the earth's motion on the refractive index of certain dielectrics. And Trouton and Noble (1903) tried to detect an expected tendency of a charged plate capacitor to face the 'ether drift'. All of them failed. The facile explanation that the earth might drag the ether along with it only led to other difficulties with the observed aberration of starlight, and could not resolve the problem. 

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Herpetology: Study Materials on Amphibians and Reptiles

Panther Chameleon (Furcifer pardalis), endemic to Madagascar.
Image courtesy link

-by Aaron S. Johnson

Introduction:

Herpetology is the zoological study of amphibians (frogs, toads, salamanders, newts, caecilians [legless amphibians]) and reptiles (turtles/tortoises, snakes, lizards, amphisbaenians [non-snake, legless squamate clade], crocodilians, tuataras).  A herpetologist is an expert in amphibian and reptile behavior, diet, ecology, taxonomy, physiology, anatomy, evolution, health, conservation, and husbandry.

Amphibians have been around for over 370 million years (m.y.) and reptiles for 310-320 m.y.  Amphibians are the descendants of a fishlike ancestor, whereas reptiles descended from a common amphibianlike ancestor.  Together, reptiles and amphibians are collectively known as "herps" and are the common ancestors of birds and mammals.  

Herps may be ectotherms, but they are voracious eaters of everything humans consider as "pests" and carriers of disease, e.g. insects, arachnids, slugs, rodents.  Needless to say, world ecological systems would collapse without them.  With the decline of amphibians and reptiles due to herbicides, pesticides, pet trade, destruction of the environment, climate change, invasive species, and pathogenic microbes, the importance of these creatures have grown ever more apparent.  Accordingly, modern herpetologists should have expertise in microbiology, chemistry, climatology, conservation, and even business administration, communications, and sociology in order to professionally problem solve as difficult issues arise. 

Space Aliens on Distant Planets—They've Got Your Attention?!

As we come across many milestones in science, another quiet one has recently snuck in too. As of February this year, we have officially exceeded a thousand extra-solar planets & counting. This inevitably begs the question of life. And an inquiry into life on other planets often brings with it many fallacies (many-times perpetrated by science dweebs themselves), as much as by little green UFO enthusiasts. Many of these fallacies stem directly from an anthromorphocentric view and an inability to ever escape from it, when forming scientific queries. While/Whether the scientists working on these projects might choose to simplify their language (if they're even aware of it) in order to popularize their understanding, they do a great disservice to understanding the subject & approach for generations by stymieing the pursuit of science. 

Study Materials on Classical Electrodynamics

Introduction:

Mechanics tells us how a system will behave when subjected to a given force. There are four forces in nature known (presently) to us. If we arrange them in order of decreasing strength, they would be:

1. Strong nuclear force
2. Electromagnetic force
3. Weak nuclear force, and
4. Gravitational force

We have often thought about questions, like: Where is friction? Where is the "normal" force that keeps us from falling through the floor? Where are the chemical forces that bind molecules together? Where is the force of impact between two billiard balls? The answer is that all these forces are electromagnetic.

Detection at t=0: looking at the beginning of time

Detection at t=0: looking at the very beginning of time, we saw the echoes of the Bang imprinted across the sky.

We’ve all heard the big news yesterday. Scientists spotted the gravitational ripples that left marks in the distribution of energy, which is strong evidence for inflation, but how did they do it?

Polarization means the electric vector of the photon oscillates in a specific direction. B-mode polarization is a pattern in the CMB radiation that can be broken into two components. One, a curl-free, gradient-only component, the E-mode, was first seen in 2002 by the Degree Angular Scale Interferometer (DASI). The second component is gradient-free, curl only, and is known as the B-mode. Cosmologists predict two types of B-modes, the first generated during cosmic inflation, and the second generated by gravitational lensing later, due to light encountering matter on its way. Gravitational waves squeeze space as they travel, and this squeezing produces a distinct pattern in the cosmic microwave background. GWs have a handedness or chirality, much like light waves, and can have left- and right-handed polarizations which makes them very recognizable.