Imagine the Universe!

Profile: Dr. Floyd Stecker

Photo of Floyd
What is Floyd's big question?


graphic of twin OWL spacecraft over the Earth

What is this image?

Floyd Stecker was born in the Bronx in New York City and grew up in the Bronx and Manhattan. Since the age of 4, he has been interested in science. Floyd's family always encouraged learning, and in fact his mother was a teacher, and an exceptionally talented one -- over the years she taught all grades from elementary through high school.

He attended the Bronx High School of Science ( where, in addition to his studies, Floyd enjoyed playing a lot of chess. The Bronx High School of Science has produced more Nobel Prize winners than any other high school - five of them, and all received their prizes in physics. With the interest Floyd had in physics already, the handwriting was on the wall.

In his undergraduate years, Floyd studied physics at the Massachusetts Institute of Technology (MIT) ( With the MIT sailing team he enjoyed many a competition on the Charles River (calculating the trajectory of the sailboat perhaps?) It was during these years that he saw the potential in studying high-energy astrophysics -- astroparticle physics in particular. Astroparticle physics is the application of particle physics to astronomy and vice versa.

Floyd's PhD thesis at Harvard ( involved calculations on the types of events in the Universe that might produce gamma rays. He used particle physics to forecast what gamma-ray astronomers might see sometime in the future, since there was not yet an experimental field of gamma-ray astronomy. His calculations could be used to plan space-based gamma-ray telescopes. Floyd's thesis lead to the publication of Cosmic Gamma Rays, the very first book on gamma-ray astronomy. Both the book and thesis have held up very well over time. It has been very satisfying for Floyd to learn from several scientists that they chose to pursue astroparticle physics, rather than the more general particle physics, in large part because of his book.

While still at Harvard, Floyd met Frank Jones, a cosmic-ray theorist from Goddard, at a meeting in Washington, D.C. Frank suggested that Floyd apply for a post-doctoral position to work with him. A post-doctoral appointment is an opportunity for a new PhD to advance his skills and experience while still under the supervision of a veteran researcher. After his post-doc, Floyd was hired as a permanent government employee at Goddard. He and Frank now work side by side, competing for the coveted "Most Comics Attached to the Office Door" prize.

Imagination in Science

Floyd is a theoretical astrophysicist, which means he uses both his knowledge and imagination to predict and find explanations for data from experiments. Theories help scientists design instruments to further their understanding. "Most people don't realize that imagination is very important to a scientist. My job lets me take what may seem like science fiction and make it into real science." For Floyd, the best parts of working in science are exploring the puzzles and the excitement of discovery. "In astrophysics today, the new puzzles and advances are coming at an almost furious pace."

Floyd's work is centered in astroparticle physics, but unlike most scientists, his interests and experience are all over the map, from cosmic rays and dark matter to infrared and gamma radiation. Past projects have included EGRET ( (gamma rays) and COBE ( (infrared), and he currently works with GLAST ( (gamma rays), OWL ( and EUSO ( (both cosmic rays). His calculations have provided predicted measurements on neutrinos from the cores of active galaxies and on dark matter, and he has put forward explanations for the creation and amount of galactic and extragalactic neutrinos and galactic gamma rays. Floyd has also presented new ways to study intergalactic infrared radiation and extragalactic gamma rays. Using cosmic gamma-ray data to test special relativity and theories of quantum gravity is Floyd's latest work. Quantum gravity involves the nature of space-time at extremely small distances -- much smaller than an atomic nucleus.

* Click here to read a news article about Floyd's work
Photo of HESS telescope
HESS cosmic gamma-ray telescope (
(courtesy HESS collaboration)

Floyd has tackled one of the biggest puzzles in physics: the detection of cosmic-ray particles here on Earth with energies above 1020 eV. These are called UHECRs, ultra-high energy cosmic rays. The energy in one UHECR nucleus is about the same as that in a Mariano Rivera fastball (New York Yankees pitcher, of course). Current theories have trouble explaining how particles can be accelerated to such high energies in cosmic sources like supernovas. New exotic physics, such as unified theory (see Floyd's big question), have been invoked to explain them.

The other part of the puzzle is in finding UHECRs on Earth. In traveling from a distant galaxy, the energy from these particles should be sapped by interactions with photons and radiation along the way. So we shouldn't see them here at all, yet we do. So far, no one knows what created them. But Floyd was able to calculate that, if they started out as heavy atomic nuclei, they could indeed negotiate a 300-million-light-year journey through the space and still arrive at Earth possessing a powerful energy.

Composite image of supernova remnant E0102-72
Supernova remnant E0102-72 (

NASA's Medal for Exceptional Scientific Achievement was presented to Floyd in 1973 for his work linking gamma ray astronomy to cosmology. And in 2002, Floyd was delighted to be awarded Goddard's John C. Lindsay Award for Space Science for his ground-breaking papers that are helping scientists to study the evolution of galaxies in a new way. His work provides a technique to measure infrared, optical, and ultraviolet radiation emitted from stars and dust in galaxies outside our own Milky Way.

The Perks

Always working with fresh and exciting ideas is Floyd's favorite part of his job. He likes being on the "frontier". (The only part of the job he dislikes is the administrative paperwork, not surprisingly.)

Photo of Maui beach

Floyd often travels to scientific meetings and universities, sometimes to give seminars or colloquia about his work. He ventures outside the U.S. a couple of times a year, but more frequently he stays in the country. Even with all the paperwork and logistics involved, Floyd really enjoys the travel and has had mostly good experiences. He has been to South Africa, Japan, Russia, and all over Europe, but Hawaii ( remains his favorite place to visit.

Floyd has a bit of a knack for languages and studied German in school. He speaks and reads it, which has come in handy during travel at times. Repeated visits to Italy have imbued him with enough conversational Italian to get by at times. And a colleague at Goddard taught him a little Russian -- "the kind you don't learn from a book!"

Typical Day

If he isn't traveling, Floyd starts the day surfing the net for new scientific papers in his many fields of interest. He is specifically looking for "e-prints" of papers that are so recent they haven't yet been published. He might read these papers right away, or print them out and set them aside temporarily to continue work on theoretical calculations already in progress. Throughout the day, Floyd keeps in contact by e-mail with collaborators on current projects, and with other physicists and astrophysicists, about subjects of mutual interest. Often in the afternoon, he attends local seminars and colloquia given by colleagues.

Other Interests

Photo of Floyd jumping a horse

"I didn't learn to ride a horse growing up in New York City!", but with his wife's encouragement (she rode horses as a child), Floyd participated in equestrian competitions for many years. He won blue ribbons in dressage, cross-country, and stadium jumping. During some of his equestrian years, Floyd also volunteered his time on a horse patrol in the Catoctin Mountains near Camp David, MD. These volunteers looked for poachers and people in trouble, and filled in the gaps for National Park rangers on weekends.

Floyd is a long-time tennis player and routinely plays for fun and exercise with a group of three other NASA scientists. He is known in the Lab for his brightly colored shirts, which are mostly Hawaiian, although the fluorescent orange one is also notable. Without either tennis shorts or a Hawaiian shirt, his colleagues don't recognize him.

He enjoys reading a variety of fiction and non-fiction books, always looking for something new and interesting, as with his science. Listening to classical, jazz, folk, and some classic rock music is another pastime. Floyd plays the piano on occasion, having taken piano lessons as a teenager. His two "barkless" African Basenjis ( envy his ability to produce beautiful music.

Questions and Answers

Q: If you weren't a scientist, what would you be?

A: If I weren't a scientist, I would probably work in some other academic field or perhaps be a writer.

Q: Which academic field? What kind of writer?

A: This is wide open!

Q: If you could invite three people from throughout history to your house for dinner, who would you invite and why?

Photo of Einstein
Portrait of Franklin

A: I would invite Albert Einstein (, who was my childhood hero, and talk physics with him. I would like to chat with Joseph Campbell ( about his fascinating insights into the myths of various cultures and what they tell us about the mind of man. I would also love to talk with Benjamin Franklin ( -- about anything and everything.

Q: Who was your favorite teacher in school? What was this teacher like, and how did he/she influence your life?

A: My favorite teacher in graduate school was Julian Schwinger (, who received the Nobel Prize for his work on quantum electrodynamics. His lectures were clear and precise and gave me a feel of what theoretical physics was about. What I learned in his courses served me well in my future work.

Q: Did you have a favorite teacher in elementary or high school?

A: My favorite teacher in high school was a biologist, Dr. Stenmore Gould. With his help, I wound up doing a microbiology research project at Columbia University ( with a bacteriophage, a virus that attacks bacteria. I liked the way he challenged us and kept the class at a high level. I also had a wonderful math teacher.

Q: What do you think is the most important technological advance that has occurred in your lifetime?

A: Definitely the computer, and for the reasons you would guess: the information revolution, the ability to get information about anything and anyone. Computer games - not so much of an advance!

Publication Date: November, 2003

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