Physics and Astronomy Northwestern University

Overview

Overview

The sheer scale of what physicists study is dazzling: astrophysicists study galaxies so far from Earth that their distance (in miles) needs 22 zeros after the last digit, whereas particle physicists study subatomic particles so light that their weight (in ounces) needs 35 zeros before the first digit! Optical physicists use ultrafast laser spectroscopy to directly observe atoms taking part in chemical reactions that last only a million billionth of a second, while just down the hall their colleagues may be studying data on other solar systems in our galaxy, to better understand how the Earth itself was formed 4.2 billion years ago. There is no other science which spans such a vast range of time, space, and matter as physics. The Physics and Astronomy program from Northwestern University allow students to be a part of this.

The other distinguishing hallmark of physics is its emphasis on basic knowledge. It has been said that the periodic table of the elements is chemistry, but understanding why the elements form a periodic table in the first place is physics. Physicists look for the hidden symmetries that underlie the natural world, and try to express them in the most universal terms possible. For example, research in the area of nonlinear dynamics has revealed that the chaotic pattern of the heartbeats in a heart-attack patient undergoing severe arrhythmia has exactly the same mathematical properties as a leaky faucet, caught halfway between on and off, which is spluttering erratically. This emphasis on looking past the surface is terrific training for any student, regardless of whether they make physics or astronomy their profession.

Modern Physics

The frontiers of physics today lie in the areas of (very) complex systems, "soft" matter, nanoscale systems, particle physics, and the physics of quantum optics and quantum entanglement. Our department has faculty working in all of these areas. In nanoscale physics, we are studying such things as how soft organic materials stretch at the atomic level when adhering to hard materials, and how the magnetization dynamics of single-domain magnetic nanoparticles (i.e., particles about a nanometer wide) might contribute to improved magnetic recording technology.

Our particle-physics faculty are working on many problems of fundamental importance; one of the more interesting is the search for so-called "neutrino oscillations". In brief, many physicists believe that a certain class of subatomic particles known as neutrinos do not maintain a constant identity as they move, but instead rotate between different "flavors" – something like a car which is either a Ford, a Honda, or a Saab, depending on how far down the road it has traveled. (This Physics and Astronomy problem has led physicists in Japan to build a neutrino detector 136 feet tall and 145 feet around, housing 50,000 gallons of water and 11,200 photomultiplier tubes, in a chamber 3,300 feet underground. Extreme devices such as this are needed, because neutrinos are extremely hard to detect.)

Modern Astronomy

Today is perhaps the most exciting time in history to be an astrophysicist. Technological breakthroughs such as adaptive optics for giant telescopes (which allow them to see clearly through the shimmer of Earth's atmosphere), orbiting space-based detectors and instrumentation, and ultra-precision measurement techniques, have revolutionized our ability to examine the Universe. In only the last decade, we have detected scores of new planets orbiting near-by stars, and discovered that "normal" matter (as we are made of) constitutes only about 15% of the mass of the Universe. (The other 85% is the mysterious, so-called "Dark Matter".)