Isaac Newton’s London life: a quiz
Isaac Newton is known as the scientist who discovered gravity, but less well-known are the many years he spent in metropolitan London, and what precisely he got up to in that time…
Understanding black holes: young star clusters filling up gaps
Since their groundbreaking discovery of gravitational waves from a pair of in-spiralling black holes back in
2015, the LIGO-Virgo-KAGRA collaboration has detected nearly 70 candidates of such events, 50 being
confirmed and published until now.
Modifying gravity to save cosmology
The unexpectedly rapid local expansion of the Universe could be due to us residing in a large void. However, a void wide and deep enough to explain this discrepancy—often called the “Hubble tension”—is not possible in standard cosmology, which is built on Einstein’s theory of gravity, General Relativity.
Supermassive black holes: monsters in the early Universe
When matter is squashed into a tiny volume the gravitational attraction can become so huge that not even light can escape, and a black hole is born. A star such as the Sun will never leave a black hole because the quantum forces between matter stop this squeezing into a sufficiently small volume.
The enduring mystery of how galaxies grow up
Astronomers have discovered that there are two different types of galaxies in the Universe: elliptical galaxies and spiral galaxies. Elliptical galaxies are dead galaxies full of very old, red stars that move on chaotic random orbits around the centre of their galaxy in such a way that makes their shape look like fluffy footballs. On […]
How old galaxy groups stay active in retirement
As recently as the start of the 20th century, the idea that the Milky Way contained everything that existed in the Universe was predominant and astronomers were unaware of the existence of other galaxies or any kind of star systems outside our galaxy. A few observed nebulae that had been identified as clusters of stars […]
Why chemical imbalance is the wrong way to talk about depression
Depression has often been described as a “chemical imbalance.” This description is helpful in that it shifts the view of depression from a moralizing, personal stance into a medical model, and it can help encourage people to receive treatment. However, the “chemical imbalance” model is outdated and inaccurate. The chemical imbalance theory started in the […]
Testing Einstein’s theory of relativity
Albert Einstein is often held up as the epitome of the scientist. He’s the poster child for genius. Yet he was not perfect. He was human and subject to many of the same foibles as the rest of us. His personal life was complicated, featuring divorce and extramarital affairs. Though most of us would sell […]
The scientific mysteries that led to Einstein’s E=mc^2 equation
Scientists deal with mysteries. As Richard Feynman once commented: “Science must remain a continual dialog between skeptical inquiry and a sense of inexplicable mystery”. Three examples: it is profoundly mysterious as to why mathematics can so accurately describe our physical world, and even predict events, such as the motion of the planets or the propagation […]
Is motion an illusion of the senses?
According to Aristotle, Zeno of Elea (ca. 490 – ca. 430 BCE) said, “Nothing moves because what is traveling must first reach the half-way point before it reaches the end.” One interpretation of the paradox is this. To begin a trip of a certain distance (say 1 meter), a traveler must travel the first half of it (the first 1/2 m), but before he does that he must travel half of the first half (1/4 m), and in fact half of that (1/8 m), ad infinitum.
Understanding quantum mechanics [quiz]
Mechanics is that part of physics concerned with stuff that moves, from cannonballs to tennis balls, cars, rockets, and planets. Quantum mechanics is that part of physics which describes the motions of objects at molecular, atomic, and sub-atomic levels, such as photons and electrons. Although quantum mechanics is an extraordinarily successful scientific theory, on which […]
Envisioning a post-crisis world
Early in World War II, in August 1941, before the United States had entered the war and Britain stood alone against Adolph Hitler, President Franklin Roosevelt and Prime Minister Winston Churchill steamed in secret aboard their respective battleships and met off the coast of Newfoundland on HMS Prince of Wales. Their aim: Shape the Post […]
Space for concern: Trump’s executive order on space resources
Among the bevy of executive actions undertaken by President Donald Trump during the COVID-19 crisis is, of all things, an executive order (issued on 6 April 2020) promoting the development of space resources, which states in part that: Americans should have the right to engage in commercial exploration, recovery, and use of resources in outer […]
The physics of swarm behaviour
The locusts have no king, and yet they all go forth in ranks, noted King Solomon some three thousand years ago. That a multitude of simple creatures could display coherent collective behavior without any leader caused his surprise and amazement, and it has continued to do so for much of our thinking over the following […]
The scientists who transformed modern medicine
Structural biology, a seemingly arcane topic, is currently at the heart of biomedical research. It holds the key to the creation of healthier, cleaner and safer lives, since it guides researchers in understanding both the causes of diseases and the creation of medicines required to conquer them. Structural biology describes the molecules of life. It […]
The problem with overqualified research
Not all research findings turn out to be true. Of those that are tested, some will need to be amplified, others refined or circumscribed, and some even rejected. Practicing researchers learn quickly to qualify their claims, taking into account the possibility of improved measurements, more stringent analyses, new interpretations, and, in the extreme, experimental or […]