TAT Blog interesting astrophysics stories

ArXiv.org Reaches a Milestone and a Reckoning

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Runaway success and underfunding have led to growing pains for the preprint server

By Daniel Garisto on January 10, 2022

What started in 1989 as an e-mail list for a few dozen string theorists has now grown to a collection of more than two million papers—and the central hub for physicists, astronomers, computer scientists, mathematicians and other researchers. On January 3 the preprint server arXiv.org crossed the milestone with a numerical analysis paper entitled “Affine Iterations and Wrapping Effect: Various Approaches.” (The Library of Alexandria, for comparison, is believed to have contained no more than hundreds of thousands of manuscripts.)
“We’re a way for authors to communicate their research results quickly and freely,” says Steinn Sigurdsson, a professor of astrophysics at Pennsylvania State University and arXiv’s scientific director. Unlike traditional scientific journals, arXiv (pronounced “archive” because the “X” represents the Greek letter chi) allows scientists to share research before it has been peer-reviewed.

 

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Beware survivorship bias in advice on science careers

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If today’s successful academics habitually work late in the laboratory, they’re likely to advocate that the next generation does the same.Credit: Thomas Barwick/Getty

Dave Hemprich-Bennett , Dani Rabaiotti & Emma Kennedy

 

A major flaw in much scientific and academic career advice is survivorship bias. This is a common logical error, involving drawing conclusions based on those who have ‘survived’ a process — and are thus more visible than those who did not. In the case of science careers advice, the bias arises because those who manage to stick to their chosen career path are there to advise the next generation of researchers on how to stay in their field.

As two postdoctoral researchers in ecology (D.H.B., D.R.) and a lecturer in learning and teaching (E.K.), we have seen many examples of worthy but ‘unsuccessful’ colleagues who left their research field against their wishes. On the flipside, the positions we hold in our respective fields are, to some extent, the result of many chance events that we experienced.

Some of our success came from hard work, grit and good judgement. But much of it came from decisions, luck and circumstances that never make it into careers advice. For example, job opportunities for D.R. and her friends have come about through having drinks with senior scientists, and D.R. was invited to publish her first book Does It Fart? thanks to a completely unplanned Twitter hashtag. Chance or serendipitous experiences such as these are impossible to replicate, yet are key to many people’s ability to stay in their chosen career.

Conversely, E.K. had to leave her original field, English literature, because she could not afford to stay in the insecure, low-paid teaching roles that were available. It is therefore important to know not only why some people ‘succeeded’, but also what pushed many more away. Assuming that all aspiring scientists and academics enjoy similar circumstances to those of their colleagues who have ‘survived’ can only damage the prospects of the next generation, and will lead to professions with much less diverse staff than could have been the case.

 

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Focus: Sound Waves Carry Mass

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Massive sound. A small amount of mass is transported along with all sound waves, according to a new theory.

March 1, 2019• Physics 12, 23
Even if you ignore general relativity, sound waves transport a small amount of mass, according to theory.

Ordinary sound waves carry a small amount of mass with them as they travel, according to a new theoretical study. The theory assumes Newtonian conditions, so the effect is unrelated to either quantum theory or the equivalence of energy and mass known from relativity. The researchers do not yet have a clear physical explanation of their mathematical results, but they say that the idea should be testable in experiments with ultracold atoms, or possibly in observations of earthquakes.

Last year, high-energy physicists Alberto Nicolis of Columbia University in New York and Riccardo Penco, now at Carnegie Mellon University (CMU) in Pittsburgh, used quantum field theory to analyze the behavior of sound waves moving through superfluid helium [1]. To their surprise, they found that the waves carry a small amount of mass, not only by virtue of Einstein’s famous formula equating energy with mass. The duo found that phonons, the quantum units of sound waves, interact with a gravitational field in a way that requires them to transport mass as they move.

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University of Tübingen ranked 42 for education

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attempto online - Forum
17.10.2018

Die Erziehungswissenschaft an der Universität Tübingen kann erneut mit Bestnoten glänzen. Nach dem am Mittwoch veröffentlichten Times Higher Education Ranking nach akademischen Fächern landeten die Tübinger Pädagogen bundesweit auf Platz 2 sowie auf Platz 42 im weltweiten Vergleich. Bereits Ende Juli hatte sich die Tübinger Erziehungswissenschaft im diesjährigen Shanghai Ranking bundesweit auf Rang eins platzieren können.

Das Times Higher Education Ranking gilt als eines der angesehensten Systeme zur Klassifizierung von Universitäten weltweit. Das Ranking vergleicht mehr als 2.000 Hochschulen in 93 Ländern. Bewertet werden unter anderem die Leistungen einer Hochschule in Lehre und Forschung, die Zahl der wissenschaftlichen Veröffentlichungen, Drittmitteleinnahmen sowie die Reputation der Einrichtungen unter Wissenschaftlerinnen und Wissenschaftlern. Das Ranking wird seit 2010 vom britischen Magazin Times Higher Education organisiert und durchgeführt.

Karl G. Rijkhoek

 

How to review a paper

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A good peer review requires disciplinary expertise, a keen and critical eye, and a diplomatic and constructive approach.
Credit: dmark/iStockphoto

By Elisabeth Pain

Sep. 22, 2016 

As junior scientists develop their expertise and make names for themselves, they are increasingly likely to receive invitations to review research manuscripts. It’s an important skill and service to the scientific community, but the learning curve can be particularly steep. Writing a good review requires expertise in the field, an intimate knowledge of research methods, a critical mind, the ability to give fair and constructive feedback, and sensitivity to the feelings of authors on the receiving end. As a range of institutions and organizations around the world celebrate the essential role of peer review in upholding the quality of published research this week, Science Careers shares collected insights and advice about how to review papers from researchers across the spectrum. The responses have been edited for clarity and brevity.

 

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ROSETTA'S COMET CONTAINS INGREDIENTS FOR LIFE

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27 May 2016


Ingredients regarded as crucial for the origin of life on Earth have been discovered at the comet that ESA's Rosetta spacecraft has been probing for almost two years.


They include the amino acid glycine, which is commonly found in proteins, and phosphorus, a key component of DNA and cell membranes.
Scientists have long debated the important possibility that water and organic molecules were brought by asteroids and comets to the young Earth after it cooled following its formation, providing some of the key building blocks for the emergence of life.

 

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Controversial dark-matter claim faces ultimate test

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Multiple teams finally have the material they need to repeat enigmatic experiment.

Davide Castelvecchi

05 April 2016

It is the elephant in the room for dark-matter research: a claimed detection that is hard to believe, impossible to confirm and surprisingly difficult to explain away. Now, four instruments that will use the same type of detector as the collaboration behind the claim are in the works or poised to go online. Within three years, the experiments will be able to either confirm the existence of dark matter — or rule the claim out once and for all, say the physicists who work on them.

“This will get resolved,” says Frank Calaprice of Princeton University in New Jersey, who leads one of the efforts.

The original claim comes from the DAMA collaboration, whose detector sits in a laboratory deep under the Gran Sasso Massif, east of Rome. For more than a decade, it has reported overwhelming evidence1 for dark matter, an invisible substance thought to bind galaxies together through its gravitational attraction. The first of the new detectors to go online, in South Korea, is due to start taking data in a few weeks. The others will follow over the next few years in Spain, Australia and, again, Gran Sasso. All will use sodium iodide crystals to detect dark matter, which no full-scale experiment apart from DAMA’s has done previously.

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Why String Theory Is Not Science

undefinedImage credit: flickr user Trailfan, via https://www.flickr.com/photos/7725050@N06/631503428.

Ethan Siegel, CONTRIBUTOR

There are a lot of different ways to define science, but perhaps one that everyone can agree on is that it’s a process by which:

knowledge about the natural world or a particular phenomenon is gathered,
a testable hypothesis is put forth concerning a natural, physical explanation for that phenomenon,
that hypothesis is then tested and either validated or falsified,
and an overarching framework — or scientific theory — is constructed to explain the hypothesis and that makes predictions about other phenomena,
which is then tested further, and either validated, in which case new phenomena to test are sought (back to step 3), or falsified, in which case a new testable hypothesis is put forth (back to step 2)…

and so on. This scientific process always involves the continued gathering of more data, the continued refining or outright replacing of hypotheses when the realm of validity of the theory is exceeded, and testing that subjects that theory to either further validation or potential falsification.

 

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Is String Theory Science?

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The idea that our Universe is part of a multiverse poses a challenge to philosophers of science.
Credit: R. Windhorst, Arizona State Univ./H. Yan, Spitzer Science Center, Caltech/ESA/NASA

 

A debate between physicists and philosophers could redefine the scientific method and our understanding of the universe
By Davide Castelvecchi, Nature magazine on December 23, 2015

Is string theory science? Physicists and cosmologists have been debating the question for the past decade. Now the community is looking to philosophy for help.
Earlier this month, some of the feuding physicists met with philosophers of science at an unusual workshop aimed at addressing the accusation that branches of theoretical physics have become detached from the realities of experimental science. At stake is the integrity of the scientific method, as well as the reputation of science among the general public, say the workshop’s organizers.
Held at the Ludwig Maximilian University of Munich in Germany on December 7-9, the workshop came about as a result of an article in Nature a year ago, in which cosmologist George Ellis, of the University of Cape Town in South Africa, and astronomer Joseph Silk, of Johns Hopkins University in Baltimore, Maryland, lamented a “worrying turn” in theoretical physics (G. Ellis and J. Silk Nature 516, 321–323; 2014).

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Potential New Particle Shows Up at the LHC, Thrilling and Confounding Physicists

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These particle tracks from the CMS experiment at the LHC show two photons arising from a roughly 750-GeV particle created in a proton-proton collision. The event may represent a new particle beyond the Standard Model of physics.
Credit: CERN

 

The gigantic accelerator in Europe has produced hints of an exotic particle that defies the known laws of physics
By Clara Moskowitz on December 16, 2015

 

A little wiggle on a graph, representing just a handful of particles, has set the world of physics abuzz. Scientists at the Large Hadron Collider (LHC) in Switzerland, the largest particle accelerator on Earth, reported yesterday that their machine might have produced a brand new particle not included in the established laws of particle physics known as the Standard Model. Their results, based on the data collected from April to November after the LHC began colliding protons at nearly twice the energy of its previous runs, are too inconclusive to be sure—many physicists warned that the wiggle could just as easily represent a statistical fluke. Nevertheless, the finding has already spawned at least 10 new papers in less than a day proposing a theoretical explanation for the particle, and has the halls and blackboards of physics departments around the world churning.

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Good Scientists Solve Problems, but Great Scientists Know What’s Worth Solving

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Abhay Ashtekar is a theoretical physicist and the founder of loop quantum gravity, an increasingly popular branch of physics that attempts to unify quantum mechanics with Albert Einstein’s theory of general relativity (which celebrates its centenary this year). Currently the Director of the Institute for Gravitational Physics and Geometry at Pennsylvania State University, Ashtekar spoke to Nithyanand Rao and Swetamber Das at IIT Madras on October 7, 2015 about his inspirations, his encounters with Subrahmanyan Chandrasekhar and Roger Penrose, work on gravity and cosmology, and his criticisms of string theory.

The freewheeling interview has been edited for clarity and divided into four parts:

Getting started on gravity and cosmology
Learning from Chandra
Challenges in loop quantum gravity
Arrogance in string theory

 

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Quantum theory: Hidden no more

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One of the weirdest bits of physics is proved beyond doubt (almost)

IN THE 1930s Albert Einstein was greatly troubled by a phenomenon that came from quantum theory. Entanglement, as it is called, forever intertwines the fates of objects such as subatomic particles, regardless of their separation. If you measure, say, “up” for the spin of one photon from an entangled pair, the theory suggests that the spin of the other, measured an instant later, will surely be “down”—even if the two are on opposite sides of the galaxy. This was anathema to Einstein and others: it looked as if information was travelling faster than light, a no-no in the special theory of relativity. Einstein was quotably derisive, calling the idea “spooky action at a distance”. But after 80 years of physicists’ fretting, a cunning experiment reported this week proves that such action is in fact how the world works.

 

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Massive Neutrinos Aren't Just This Year's Nobel Prize, They're The Future Of Physics

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If you want to describe the Universe we live in today, from a physical point of view, there are only three things you need to understand:

  • What different types of particles are allowed to be present within it,
  • What the laws are that govern the interactions between all those different particles, and
  • What initial conditions the Universe starts off with.

If you give a scientist all of those things and an arbitrary amount of calculational power, they can reproduce the entirety of the Universe we experience today, limited only by the quantum uncertainty inherent to our experience.

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Discovery of a new class of particles at the LHC

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Possible layout of the quarks in a pentaquark particle. The five quarks might be tightly bound (left). They might also be assembled into a meson (one quark and one antiquark) and a baryon (three quarks), weakly bound together (Image: Daniel Dominguez)

 

The LHCb experiment at CERN’s Large Hadron Collider has reported the discovery of a class of particles known as pentaquarks. The collaboration has submitted today a paper reporting these findings (link is external) to the journal Physical Review Letters.

 

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