plancking

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Where is the cosmic microwave background?

“So the CMB isn’t the end of the Universe, but rather the limit of what we can see, both distance-wise (as far as we can go) and time-wise (as far back as we can go). Until we can directly detect the signatures of what was released earlier – the cosmic neutrino background, gravitational waves from inflation, etc. – the CMB will be our window into the earliest time we can observe: 380,000 years after the Big Bang.”

The farther away in space we look, the farther back in time we’re seeing. Light arriving from a star ten light years away is ten years old; light that took a billion-year journey from a distant galaxy is a billion years old. If we look out today at the most distant light we can see, we discover that it originates from the Big Bang itself: the Cosmic Microwave Background, or CMB. But this doesn’t mean the light has never interacted with anything since the birth of the observable Universe. In fact, many arose from matter/antimatter annihilations, all of them have scattered off of charged particles, and the CMB photons we detect today were all released when the Universe was a few hundred thousand years old. Because of the way the Big Bang works, the particles are literally everywhere, all at once, including right here.

Come get the full story on where the CMB actually is, and what it means when we state its age and distance!

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Mostly Mute Monday: Stunning Pictures Of The Milky Way’s Magnetic Field

“From the light’s polarization, we can reconstruct the galaxy’s magnetic field. And by superimposing it over the foreground emission map, we can see for the first time how our galaxy’s structure and magnetic field are interrelated. What we found was an intricate relationship between dust grains — the precursors to stars – and the giant magnetic structures we find, some of which extend for over a thousand light years in diameter.”

If you want to view the Milky Way in all its true splendor, you need to go beyond visible light, as the cosmic dust that gives rise to new stars also absorbs visible light, robbing us of a view of our galaxy. But those other wavelengths that are more transparent to the dust — infrared and microwave — are absorbed by Earth’s atmosphere. If we want to see what’s going on, we’ve got to go to space. With nine different frequency maps covering the entire sky, the ESA’s Planck satellite not only can determine what’s through that dust, but it can measure the effects of the Milky Way’s magnetic field due to the polarization of light, showing the future of star birth in our own galaxy.

After a short hiatus while we worked to figure it out, our Mostly Mute Monday series is back!

Letters on Wave Mechanics. Schrödinger Planck • Einstein • Lorentz, Edited by K. Przibram for the Austrian Academy of Sciences, Translated and with an Introduction by Martin J. Klein, Philosophical Library, New York, 1967

German scientists to begin identifying Nazi victims’ brain specimens 

German scientists are to begin identifying thousands of brain specimens belonging to people killed by the Nazis because they had a disability or were ill.

The three-year research project into the specimens in the Max Planck institutes’ possession, which will begin in June, aims to build a database listing the names of all “euthanasia” victims. “It will include basic biographical data on the victims, their institutional treatment, and the criteria used to select the victims,” the Munich-based, non-profit Max Planck Society said in a statement.

“The manner of their death will also be documented along with data on the removal of the brain … and the research carried out on [it].”

Adolf Hitler’s so-called “euthanasia” programme, in which doctors and scientists actively participated, sought to exterminate the sick, physically and mentally disabled people, those with learning disabilities and those considered social “misfits”.

Between January 1940 and August 1941, doctors systematically gassed more than 70,000 people at six sites in German-controlled territory, until public outrage forced them to end the overt killing. But tens of thousands more died across Europe before the Nazis were defeated in 1945, through starvation, neglect or deliberate overdoses administered by caregivers. Many also underwent bizarre medical experiments and forced sterilisations because of their supposed genetic inferiority.

Hitler’s programme sought to exterminate physically and mentally disabled people and those considered ‘misfits’. Photograph: Popperfoto/Getty Images

World’s Greatest Physicists, Geniuses Meet in 1927

Solvay Conference 1927

First row: Irving Langmuir, Max Planck, Marie Curie, Hendrik Lorentz, Albert Einstein, Pierre Langevin, Charles Eugene Guye, C. T. R. Wilson, Owen W. Richardson

Second row: Peter Debye, Martin Knudson, W. Lawrence Bragg, Hans Kramer, Paul Dirac, Arthur Compton, Louis de Broglie, Max Born, Niels Bohr

Third row: Auguste Piccard, Émile Henriot, Paul Ehrenfest, Edouard Herzen, Théophile de Donder, Erwin Schrodinger, Jules-Emile Vershaffelt, Wolfgang Pauli, Werner Heisenberg, Ralph Howard Fowler, Leon Brillouin

Absents: Sir W. H. Bragg, H. Delandres et E. Van Aubel

Image credit: Hadi Nur

nature.com
Collapse of Aztec society linked to catastrophic salmonella outbreak
DNA of 500-year-old bacteria is first direct evidence of an epidemic — one of humanity's deadliest — that occurred after Spanish conquest.

One of the worst epidemics in human history, a sixteenth-century pestilence that devastated Mexico’s native population, may have been caused by a deadly form of salmonella from Europe, a pair of studies suggest.

In one study, researchers say they have recovered DNA of the stomach bacterium from burials in Mexico linked to a 1540s epidemic that killed up to 80% of the country’s native inhabitants. The team reports its findings in a preprint posted on the bioRxiv server on 8 February1.

This is potentially the first genetic evidence of the pathogen that caused the massive decline in native populations after European colonization, says Hannes Schroeder, an ancient-DNA researcher at the Natural History Museum of Denmark in Copenhagen who was not involved in the work. “It’s a super-cool study.”

Dead bodies and ditches

In 1519, when forces led by Spanish conquistador Hernando Cortés arrived in Mexico, the native population was estimated at about 25 million. A century later, after a Spanish victory and a series of epidemics, numbers had plunged to around 1 million.

The largest of these disease outbreaks were known as cocoliztli (from the word for ‘pestilence’ in Nahuatl, the Aztec language). Two major cocoliztli, beginning in 1545 and 1576, killed an estimated 7 million to 18 million people living in Mexico’s highland regions.

“In the cities and large towns, big ditches were dug, and from morning to sunset the priests did nothing else but carry the dead bodies and throw them into the ditches,” noted a Franciscan historian who witnessed the 1576 outbreak.

There has been little consensus on the cause of cocoliztli — although measles, smallpox and typhus have all been mooted. In 2002, researchers at the National Autonomous University of Mexico (UNAM) in Mexico City proposed that a viral haemorrhagic fever, exacerbated by a catastrophic drought, was behind the carnage2. They compared the magnitude of the 1545 outbreak to that of the Black Death in fourteenth-century Europe.

Bacterial genomics

In an attempt to settle the question, a team led by evolutionary geneticist Johannes Krause at the Max Planck Institute for the Science of Human History in Jena, Germany, extracted and sequenced DNA from the teeth of 29 people buried in the Oaxacan highlands of southern Mexico. All but five were linked to a cocoliztli that researchers think ran from 1545 to 1550.

Ancient bacterial DNA recovered from several of the people matched that of Salmonella, based on comparisons with a database of more than 2,700 modern bacterial genomes.

Further sequencing of short, damaged DNA fragments from the remains allowed the team to reconstruct two genomes of a Salmonella enterica strain known as Paratyphi C. Today, this bacterium causes enteric fever, a typhus-like illness, that occurs mostly in developing countries. If left untreated, it kills 10–15% of infected people.

It’s perfectly reasonable that the bacterium could have caused this epidemic, says Schroeder. “They make a really good case.” But María Ávila-Arcos, an evolutionary geneticist at UNAM, isn’t convinced. She notes that some people suggest that a virus caused the cocoliztli, and that wouldn’t have been picked up by the team’s method.

The question of origin

Krause and his colleagues’ proposal is helped by another study posted on bioRxiv last week, which raises the possibility that Salmonella Paratyphi C arrived in Mexico from Europe3.

A team led by Mark Achtman, a microbiologist at the University of Warwick in Coventry, UK, collected and sequenced the genome of the bacterial strain from the remains of a young woman buried around 1200 in a cemetery in Trondheim, Norway. It is the earliest evidence for the now-rare Salmonella strain, and proof that it was circulating in Europe, according to the study. (Both teams declined to comment on their research because their papers have been submitted to a peer-reviewed journal.)

“Really, what we’d like to do is look at both strains together,” says Hendrik Poinar, an evolutionary biologist at McMaster University in Hamilton, Canada. And if more ancient genomes can be collected from Europe and the Americas, it should be possible to find out more conclusively whether deadly pathogens such as Salmonella arrived in the New World from Europe.

The existence of Salmonella Paratyphi C in Norway 300 years before it appeared in Mexico doesn’t prove that Europeans spread enteric fever to native Mexicans, says Schroeder, but that hypothesis is reasonable. A small percentage of people infected with Salmonella Paratyphi C carry the bacterium without falling ill, so apparently healthy Spaniards could have infected Mexicans who lacked natural resistance.

Paratyphi C is transmitted through faecal material, and a collapse of social order during the Spanish conquest might have led to the poor sanitary conditions that are ripe for Salmonella spread, Krause and his team note in the paper.

Krause’s study offers a blueprint for identifying the pathogens behind ancient outbreaks, says Schroeder. His own team plans to look for ancient pathogens in Caribbean burial sites that seem to be linked to catastrophic outbreaks, and that were established after the Europeans arrived. “The idea that some of them might have been caused by Salmonella is now a distinct possibility,” he says.

Lise Meitner (1878 - 1968)
Avusturyalı bilim insanı.

Max Planck'ın derslerini izlemek için Berlin'e gider. Kaiser Wilhelm Kimya Enstitüsü'nde kalır. 1926'da fizik profesörü olan Meitner, 1938'de Nazi yönetiminden kaçarak İsveç'e sığınır. İsveç Bilimler Akademisi'ne üye seçilir. 1939'da Otto Hahn ve kendi yeğeni Otto Robert Frisch ile birlikte nötronla bombalanan uranyumdan sonra baryumun var olmasının atom çekirdeğinin parçalandığını gösterdiğini ileri sürmekle ün kazanır.

Lise Meitner sıvı damlası denilen bir yöntemle nükleer fisyon olayını çözmüş ve bu durumu Nobel'e kadar götürmüştür. Meitner çalışmalarını bir dönem ayrı kaldıkları Otto Hahn'a gönderir, Otto Hahn teoriyi ve denklemleri kendi yazmışcasına Nobel komitesine iletir ve çalışmada ne Meitner ne de Strassman'dan (diğer bir çalışma arkadaşıdır) bahseder böylece Nobel Ödülünü tek başına alır. Bu durum Meitner'i derinden etkiler, ondan sonrada herhangi bir çalışmada bulunmamıştır.

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Ask Ethan: Why is there a limit to what physics can predict?

“Why are there these units (Planck units) which you can’t further divide?”

There are fundamental limits to the Universe, in the sense that there are scales where our laws of physics break down. You can’t break matter or energy up into infinitely small pieces, and the same goes – we think – for space and time. But is that necessarily all true, and is that what the Planck scale means? Not quite. Rather, these are scales at which our laws of physics stop giving reliable predictions, as we make these mass, energy, length and time scales out of three constants fundamental to our physical theories: the gravitational constant, the speed of light and Planck’s constant. They do have strong physical implications, but they don’t necessarily mean these scales can’t be divisible further. After all, every particle in existence has a mass far below the Planck mass!

What are the limits to the Universe, and how are they related to Planck units? Find out on this week’s Ask Ethan!

thefoxninja17  asked:

As a Christian, how have you responded to the people who try to disprove and denounce your faith with science and evolution?

Calmly.

I don’t agree with the belief that science and faith cannot coexist. Yes, many of the greatest minds in history never practiced religion, however, just as many of the greatest minds did. These minds did not believe their faith contradicted what they studied from the world around them, and these individuals have greatly impacted the way we study the world. Max Planck? Issac Newton? Lord Kelvin? The very men we name units of measurement after? They believed in God. In fact, many of them became stronger believers the MORE science marched forwards.

“In the last few years astronomy has come together so that we’re now able to tell a coherent story of how the universe began. This story does not contradict God, but instead enlarges [the idea of] God.”

Joel Primack, co-developer of the cold dark matter theory

However, I also believe that denying science is just as narrow-minded and arrogant as denouncing religion as intellectually stagnant. I believe that is completely disrespectful towards those individuals who have dedicated their lives towards the noble goal of understanding the world around us. Yes, some scientists are arrogant and dishonest, but every group has some of those kinds of people so let’s not paint in broad strokes. Scientists put a lot of work into what they do; show them some appreciation.