For Professor John Cromwell Mather (1946), recipient of the 2006 Nobel Prize in Physics and Senior Project Scientist at the James Webb Space Telescope (JWST), the Standard Cosmological Model still needs to explain three crucial issues: dark matter, dark energy, and the early universe’s expansion.
Mather, the leading astrophysicist at NASA’s Goddard Space Center (GSFC), told Ciencia del Sur that 1,500 people were involved in the project that led to his Nobel Prize — and not only scientists. He also stressed that human and social sciences play an important role in cutting-edge research centers.
The first part of this interview that Professor Mather generously granted Ciencia del Sur was conducted over the internet and deals with the challenges faced by his team at the Cosmic Background Explorer (COBE) from 1989 to 1993, his vision of science, and the most accurate theories regarding the begging of the Universe. It has been edited for clarity.
Mather was born in Roanoke, Virginia (United States) in 1946, the same year that Liza Minelli and Timothy Dalton were born. But instead of becoming a star, he went on to study them. He completed his Ph.D. in Physics at the University of California, Berkeley.
In 2006, along with George F. Smoot, he received the Nobel Prize in Physics for the «discovery of the blackbody form and anisotropy of the cosmic microwave background radiation«. A long list of awards include the Robinson Prize, the Franklin Physics Medal, and the Gruber Foundation’s Cosmology Prize.
– In an interview with NASA, you said there is much pleasure in the pursuit of knowledge. Is science the best tool to satisfy our curiosity?
Scientific investigation goes beyond curiosity to the search for reliable, reproducible results and deep understanding. But there is much of great importance that can’t be reproduced or understood, and curiosity is still a great attitude to have.
How do you feel when you participate in a group? What do you think right now? (And a moment later it will be different.) Do you love me, and what does that mean?
-Your work helped to enormously improve modern cosmology. Is the field now more precise and accurate thanks to your research?
Yes, our COBE satellite team measured the heat of the Big Bang with extraordinary precision, and made the first map of its hot and cold spots. Following our work, thousands of scientists have built dozens of new instruments and two satellites to make much better measurements of the spots.
We now have such extraordinary capabilities that we have developed a standard model of cosmology that fits all the data very well. But it also demands the existence of mysterious dark matter and dark energy. We had good reason to suspect their existence many years ago.
-You have made many contributions to science, but which is your most important one?
I helped lead the scientific team for the COBE satellite, and we made very precise measurements and discovered the hot and cold spots (anisotropy) of the background radiation.
My most personal contribution was the concept for the Far Infrared Absolute Spectrophotometer (FIRAS), which compared the cosmic background radiation spectrum to that of an ideal blackbody.
-Did you intend to prove the Big Bang theory when you started working with COBE? How did you achieve such precision?
Personally, I never much doubted the general idea of the Big Bang theory. I would have been shocked if it had been false. But I never anticipated the importance of the anisotropy measurements. Our team measured the spots for the first time, and that encouraged a worldwide effort to do even better.
– What kind of problems did you encounter during the COBE project?
Most of the problems solved by the COBE team were about engineering. How do you make instruments that are capable of measuring signals far fainter than ever measured before? How do you know that the measurements are correct, and not the result of some fault of the instruments, or some unexpected objects in the sky?
How do you make instruments function properly at a temperature of 1.5 degrees above absolute zero? How can the observatory survive launch on top of a rocket? And in our case, how can you rebuild the observatory after the Space Shuttle Challenger exploded, so that it could be launched on a Delta rocket?
-Why is it so difficult to find a complete and unified theory of the cosmos? What is holding us back?
We actually have succeeded in making a Standard Cosmological Model, and it explains everything we can see, from the hot and cold spots of the cosmic microwave background radiation, to the distribution of galaxies, and the history of their formation after the Big Bang.
But there are three big problems left. First, what is the dark matter? We’ve never detected any of it in a laboratory. We don’t know if it’s made of particles or not, or if there’s more than one kind.
Second, what is the dark energy? Einstein gave a formula that fits the measurements, but his formula doesn’t tell us anything about how it works.
– And the third one?
Third, what was the universe like when it was very young, and what made it expand so rapidly and uniformly?
We have a popular theory called inflation, and it fits the measurements, but that doesn’t mean it’s true or complete.
– We already know what happened after the Big Bang, but can we find out what happened before? Is it a truly cosmological question? Was there anything?
I think of this as running the movie of the expanding universe backwards in our minds.
Picture the galaxies moving back together, getting compressed so much that atoms are ripped apart, then the protons and neutrons are ripped apart into quarks, etc. What happens when the temperatures and densities are extreme? If we just keep pushing farther back, the temperatures and densities get higher and higher.
But they never become “infinite” because infinity is not a number or a place, and “infinite” is an adjective, meaning without any limit.
So our imagination is not sufficient to go beyond this. But perhaps we could guess some equations of physics that would describe how this extreme state came from something else. Some people propose that the universe is now expanding after originally collapsing and bouncing. So far we have no way to test this idea and I can’t answer your question.
-What role should the human or social sciences play in academia and research centers?
I think the human and social sciences are much more difficult than the physical sciences, and also extremely important. Biological and social complexity far exceeds anything we can study in physics.
-Has your life changed a lot since you were awarded the Nobel Prize? How many people helped with the research?
No, my life changed very little after the prize was announced. Our team was very proud that our work had been recognized.
There were at least 1,500 people on the team, including engineers, technicians, scientists, computer scientists, managers, secretaries, accountants, etc.
-Did the award change your scientific work for better or worse? That is, did you begin to write more papers?
No, no more papers than before! I was already working on the James Webb Space Telescope, and it still has not been launched. Launch is planned for October 2018.