One sure way for a physicist to spark a lively debate at almost any gathering is to quote Sir Ernest Rutherford (1871-1937, a nuclear physicist and a Nobel Prize Laureate, photo at left), who once said that "All of science is either physics or stamp collecting."

On the one hand, it is clear this quote is mostly humorous caricature, particularly in view of the fact that Rutherford won his Nobel Prize in Chemistry, not in Physics!  On the other hand, the humor of the quip does depend upon its sly reference to a genuinely distinguishing facet of physics:  Physics is the broadest of the sciences, and more than any other seeks to explain the natural world in the most universal manner possible.

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 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 (not dripping steadily).  This emphasis on looking past the surface is terrific training for any student, regardless of whether they make physics or astronomy their profession.

Aerial view of Fermilab.  Numerous NU physics faculty and students work here.  For perspective, the white building at the upper left is 15 stories tall.  (Click photo for larger view.)

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 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.)  At Northwestern, we are working on a project which will culminate in a an intense beam of neutrinos being directed literally through the Earth, from Fermilab here in Chicago to an underground detection chamber some 600 miles away in the old Soudan mine near Duluth, Minnesota!  If successful, the project will decisively determine whether neutrinos "oscillate" or not, and if so, how quickly they do it.

To investigate these phenomena, our astrophysics faculty use x-ray, ultraviolet, optical, infrared, and radio telescopes located almost everywhere: Chile, Arizona, Hawaii, outer space, even the South Pole.  (We have had three undergraduate physics majors conduct independent studies at the South Pole, helping Professor Giles Novak with his research on the magnetic field at the center of the Milky Way galaxy.)

Our theoretical astrophysics faculty study exotic objects such as black holes, neutron stars, and white dwarf stars by calculating their properties using certain assumptions, then comparing these to experimental observations.  The "official" logo for this research group shows a white dwarf star in orbit about a giant red star, with the dense dwarf pulling in gas from the edge of the red star in a giant whirlpool.  This is because such objects do exist, and eventually, as too much mass pours down upon the white dwarf star, the dwarf collapses and then explodes with the energy of a hundred billion Suns.  Such events are called supernovas, and they generate the heavy elements that make up ourselves and the Earth.

The department has very close ties to the Fermi National Accelerator Laboratory and Argonne National Laboratory, both of which are located in the Chicago area.  The department's faculty carry out a wide variety of experiments at both labs, in addition to experiments carried out on the Evanston campus.  Our faculty also routinely use the facilities of other large government laboratories, such as the Advanced Photon Source at Argonne National Laboratory (Argonne, Illinois), the National Synchrotron Light Source at Brookhaven Laboratory (Brookhaven, New York), the National Very High Magnetic Field Laboratory in Tallahassee, Florida, and the CERN accelerator laboratory in Geneva, Switzerland.

Our physics faculty are particularly active in the areas of low-temperature physics, materials physics, superconductivity, nonlinear phenomena, elementary particle physics, and the physics of nuclei.  Among other topics, our astronomy faculty are studying black holes, the physics of the center of the Milky Way galaxy, the accretion disks around neutron stars, the composition of the interstellar gas, and the large-scale structure of the Universe.

As a result of its top-notch research programs, the department has been very successful in obtaining federal research grants from the National Science Foundation, NASA, the Department of Energy, and other agencies.  These grants now total over $7.1 million per year.  Undergraduates often participate in these research programs, gaining hands-on experience that is an invaluable addition to classroom experience.  The department frequently has funds for hiring undergraduate research assistants to participate in these programs.

In one recent project, a student built telescopic filters to detect microwaves coming from the galactic center.  These filters will be used on telescopes at the South Pole and on Mauna Kea in Hawaii. Another student worked with a professor on a project in high-energy particle physics and co-wrote a paper that was published in the Physical Review, a leading physics journal.  Another student studied the chemistry of interstellar clouds and is first author on a paper published in the Astrophysical Journal.

The department also encourages students to participate in the departmental honors program.  To qualify for honors, students must maintain a minimum grade point average of 3.3, take two advanced physics or astronomy courses beyond those required, and also take two extra independent study or graduate-level courses.  Independent study includes a research project. A college-wide committee awards departmental honors after reviewing recommendations from the department.

Historically, about 60% of the physics majors at Northwestern have chosen to pursue advanced degrees after graduation.  Most of these degrees are in physics and astronomy, but include many other disciplines:  law, business, medicine, and engineering.  A rapidly growing area of graduate interest is medical physics, including nuclear medicine and diagnostic technology.  A more detailed listing of the physics graduate schools that our majors are attending is available here.

Nationwide, over 90% of the students who pursue PhDs in physics or astronomy are fully supported as either research or teaching assistants throughout their entire graduate careers.  They receive full tuition waivers and monthly stipends in return for part-time teaching or research.  The very low cost of obtaining a graduate degree in physics or astronomy is one of the major incentives that leads the majority of physics bachelors to enter PhD programs.  Afterwards, most PhDs enter careers in basic research in universities, government, or industry.

A few undergraduate alumni who have gone on to the PhD include:

Professor Barbara Ryden (WCAS '80), now on the faculty at The Ohio State University.  Professor Ryden has recently written a well-received textbook, "Introduction To Cosmology", published by Addison-Wesley.

Professor Steven Majewski (WCAS '80), now on the faculty at the University of Virginia.  Professor Majewski has won several honors, including being named a Packard Fellow, a Cottrell Scholar, and a National Science Foundation Young Investigator.

Dr. Geralyn "Sam" Zeller (WCAS '94), is studying neutrino oscillations at Fermilab.  Currently a Research Associate with Columbia University, Dr. Geller won the American Physical Society's 2003 Tanaka Award for best particle-physics thesis.

Dr. Brian Patt (WCAS '99), has recently completed his PhD studies at MIT.  His thesis is on string theory, and his thesis advisor was Nobel Laureate Frank Wilczek.

A recent survey of Northwestern physics/astronomy undergraduate alumni who chose not to attend graduate school revealed a remarkable diversity of career paths.  The largest group, about 24% of the total, had become self-employed entrepreneurs, mostly in the areas of computer and engineering consulting.  Other employment paths included industrial research and development, business management (often in technological companies), computing, government public-policy research, law, engineering, medicine, the military (with technical/engineering duties), technical sales (such as very expensive, very complex CAT-scan equipment), high-school teaching, accounting, museum or library work, police forensics, nonprofit social work, freelance writing, veterinary medicine, and stock brokerage.