The centre of the Milky Way is a very crowded region, hosting a dense and compact cluster of stars—the so-called nuclear star cluster—and a supermassive black hole (SMBH) weighing more than 4 million solar masses. A star cluster is an ensemble of stars kept together by their own force of gravity. These large systems are found in the outskirts of every type of galaxy, being comprised of up to several million stars.
As a mathematician who focuses his attention on a field called dynamics, I am often asked when queried about my area of specialty, exactly what is a dynamical system? I usually answer something like: “I study the mathematics underlying what is means to model something mathematically.” And this seems to work as most people have a basic understanding that mathematics is used in science and engineering to model either a physical or an abstract process and to mine it for information.
Healthcare is expensive, and not just in high income countries. Those who are suffering or struck by illness in resource limited countries are often unable to afford services that can provide them the care they need. Inequitable access to health services continues to be among the greatest public health challenges of our time. Since becoming […]
The periodic table turns 150 next year. Given that all scientific concepts are eventually refuted, the durability of the periodic table would suggest an almost transcendent quality that deserves greater scrutiny, especially as the United Nations has nominated 2019 as the year of the Periodic Table. These days it seems that physics gives a fundamental explanation of the periodic table, although historically speaking it was the periodic table that gave rise to parts of atomic physics and quantum theory. I am thinking of Bohr’s 1913 model of the hydrogen atom and his extension of these ideas to the entire periodic table.
A February 2017 Workshop on Robustness, Reliability, and Reproducibility in Scientific Research was sponsored by the US National Science Foundation (NSF). The workshop was part of NSF’s response to growing concerns in Congress triggered by increasing media coverage of an apparent lack of reproducibility among findings, especially in clinical sciences. The participants, spanning diverse scientific subfields, were charged to assess the extent of any problems of reliability and reproducibility, and to formulate next steps toward solutions.
In 2004, John Prescott, then Deputy Prime Minister in Tony Blair’s New Labour government, remarked, “the tectonic plates appear to be moving”, referring to the impending downfall of Mr Blair. Since then, the tectonic plates metaphor has been applied to just about every major political transition, including events following the UK referendum on leaving the European Union and the election of Donald Trump as US President.
At the center of every galaxy is a supermassive black hole. Looking at the wider scale, is it possible that these gravity monsters influence the overall structure of our universe? Using a new computer model, astrophysicists have recently calculated the ways in which black holes influence the distribution of dark matter, how heavy elements are produced and distributed throughout the cosmos, and where cosmic magnetic fields originate.
Frank Wilczek famously wrote: “A recurring theme in natural philosophy is the tension between the God’s-eye view of reality comprehended as a whole and the ant’s-eye view of human consciousness, which senses a succession of events in time. Since the days of Isaac Newton, the ant’s-eye view has dominated fundamental physics. We divide our description of the world into dynamical laws that, paradoxically, exist outside of time according to some, and initial conditions on which those laws act.
Throughout the month of March, Oxford University Press will be celebrating women in STM (science, technology, and medicine) with the objective of highlighting the outstanding contributions that women have made to these fields. Historically many of the contributions made by women have gone unsung or undervalued, and these fields have been male-dominated and inaccessible for women to enter.
Ever since it was realised that the stars are other suns, people have wondered whether any of them are accompanied by planets, or ‘exoplanets’ as we now call them. Speculation along these lines were among the charges that led to Giordano Bruno being burned at the stake in the year 1600. It is only since the 1930s that astronomers seriously thought they had the observational tools to be able to find out.
At the beginning of the 19th century, Thomas Young proved that light was a wave phenomenon. He did so by illuminating a screen (in an otherwise darkened room) with a beam of sunlight that had passed through a card with two slits in it. The proof was the interference pattern on the screen, whose alternating light and dark portions could only have occurred if light consisted of waves, not particles.
White dwarfs are the remnants of solar-like stars that have exhausted the reservoir of fuel for the nuclear fusion reactions that powers them. It is widely believed, based on theoretical considerations, that young white dwarfs should experience a phase of contraction during the first million years after their formation. This is related to the gradual cooling of their interior which is not yet fully degenerate.
At a party, on a plane, in the locker-room, I’m often asked what I do. Though tempted by one colleague’s adoption of the identity of a steam-pipe fitter, I admit I am a professor of philosophy. If that doesn’t end or redirect the conversation, my questioner may continue by raising some current moral or political issue, or asking for my favorite philosopher.
How big is the Moon in the sky? What is its angular size? Extend your arm upward and as far from your body as possible. Using your index finger and thumb, imagine that you are trying to pluck the Moon out of the sky ever so carefully, squeezing down until you are just barely touching the top and bottom of the Moon, trapping it between your fingers. How big is it?
Open most textbooks titled “Modern Physics” and you will see chapters on all the usual suspects: special relativity, quantum mechanics, atomic physics, nuclear physics, solid state physics, particle physics and astrophysics. This is the established canon of modern physics.
Recently, we’ve heard that Volvo are abandoning the internal combustion engine, and that both the United Kingdom and France will ban petrol and diesel cars from 2040. Other countries like China are said to be considering similar mandates.