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.
If you studied history, sociology, or English literature in your post-secondary education, it was probably in part because physics was too hard to understand or not as interesting. If you did not pay attention to quiet developments in the world of physics over the past several decades, you missed some very interesting important discoveries. Today, physics is not what our parents or even any of us who went to high school or university in the last quarter of the twentieth century learned because the physicists have been busy learning a lot of new things.
Quantum physics is one of the most important intellectual movements in human history. Today, quantum physics is everywhere: it explains how our computers work, how lasers transmit information across the Internet, and allows scientists to predict accurately the behavior of nearly every particle in nature. Its application continues to be fundamental in the investigation of the most expansive questions related to our world and the universe.
In ordinary discourse, a theory is a guess or a surmise, as in “that’s only a theory.” In science, however, a theory is a well-substantiated explanation of some aspect of the natural world that is supported by confirmed facts and/or observations. Verification of a theory’s predictions ensures its eventual acceptance by the community of scientists working in the particular discipline.
We all like the convenience of electrical energy. It lights our home and offices, and drives motors that are needed in heating, ventilation, and air conditioning systems that keep us buildings comfortable no matter what the temperature is outside. It’s essential for refrigeration that secures our food supply. In short, it makes modern life with all its comfort and conveniences possible.
Space exploration has dominated human imagination for the most of the last 125-odd years. Every year we learn more about what lies beyond the limits of Earth’s atmosphere. We learn about extraterrestrial resources, such as metals on asteroids or water on the Moon; we discover new exoplanets that may be able to support life; we research new technologies that will get us onto planets a little closer to home, such as Mars.
One of the amazing ideas to emerge from Einstein’s theory of general relativity was the possibility of gravitational waves rippling their way across the cosmos. It took a century to verify this prediction. Their existence was finally confirmed by LIGO (the Laser Interferometer Gravitational-wave Observatory) in September 2015.
Cassini was the NASA-developed Saturn orbiter, and Huygens was the European-built probe that sat on-board, which would eventually descend on to the surface of Saturn’s biggest moon, Titan. Cassini will come to an end on 15th September 2017, when it makes its final approach to Saturn, diving in to the atmosphere (sending data as it goes), and finally burning up and disintegrating like a meteor.
Back to university means picking out the best textbooks to use for your studies. If you’re just starting out in your first year of studies or are pursuing further degree in a more specialized field, we have some great resources to explore. From the basics of fundamental physics to the intricacies of understanding light-matter interaction, this list provides the best starting point for under-graduates and post-graduates alike.
From Copernicus to Einstein, the field of Physics has changed drastically over time. With each new theory, further hypotheses appear that challenge conventional wisdom. Today, although topics such as the Big Bang Theory and General Relativity are well-established, there are still some debates that keep physicists up at night. What are your thoughts on the five of the biggest current debates in Physics?