Vera Rubin was a very rare bird forty years ago: a female astronomer. Galaxies were her life’s work. In her day the notion that there are many galaxies outside our own was only a few decades old. Inspired by her ‘just plain old curiosity’, her PhD thesis suggested galaxies are not scattered randomly: they come […]
By 1900 the speed of light was known to be a constant. Many experiments had measured it. In 1905 Albert Einstein took a giant leap forward. He said this cosmic speed limit—denoted by the symbol c—is not just a measured fact; it is a fundamental property of the universe. This became the basis of his […]
There is no absolute frame of reference. It’s called the Principle of Relativity. Problem is: The principle is wrong. How so? Let’s take a closer look at what it is. Italian physicist Galileo Galilei had an idea. He said an experiment that’s done inside a smoothly moving ship can’t tell you that it’s moving. In […]
When did time begin? Science now has an answer. How did time begin? For millennia this was a subject for speculation, little of it based on science. But there is now a philosophic answer. Space came first. Time began soon after space. Very soon. Here’s how. From recent measurements we know that time began 13,799,000,000 […]
Does time flow? It is a fundamental question. It has confounded physics for hundreds of years. It still does. We sense the flow of time. Today many physicists say this is an illusion. I say they don’t understand. Physics at the very largest and the very smallest scales leads to a simple way to make […]
Quadrillions of galaxies make up some structures in the universe. How did such structures arise? How do the galaxies that they are made of grow? As Winston Churchill said of Russia, this is a riddle wrapped in a mystery inside an enigma. Now primordial black holes offer us new hope of an answer. What is […]
For years Dark Matter has confronted physics with a massive mystery. A recent article describes it as ‘the invisible substance that astronomers believe accounts for about 80% of the stuff in the universe.’ But what is it? This question has physicists searching for obscure new particles with the world’s largest machine, the Large Hadron Collider. […]
Two weeks ago we took a look at a question from systems engineer Muralidharan Thiyagarajan. Referring to the observation that space everywhere is expanding, he asks: ‘What creates the space?’ My answer is: At the Planck level (named for German physicist Max Planck who first described it) where space is made of incredibly tiny quanta, […]
We like to think of laws of physics as fundamental, as properties of the universe. Actually, not. They are our inventions, tales we tell ourselves in terms of concepts we construct. They are good statistical approximations. But they don’t tell us what’s really going on. The real world is happening at Planck scale, named for […]