John Mather, a recipient of the Nobel Prize for Physics, will lecture at the October meeting of the Westminster Astronomical Society (WASI).
The title of his presentation is “The History of the Universe from the beginning to the end: where did we come from, where can we go?”
Details about the free meeting are given later. But first some background about the speaker, Dr. John Mather (NASA-Goddard).
After receiving his Ph.D. in physics from the University of California at Berkeley in 1974, Mather led the proposal efforts for the Cosmic Background Explorer (COBE) satellite while a postdoctoral fellow at the Goddard Institute for Space Studies in New York City. After that he came to the Goddard Spaceflight Center in Maryland where he worked on the Far Infrared Absolute Spectrophotometer (FIRAS) instrument on COBE as the Study Scientist, Project Scientist, and finally as Principal Investigator.
COBE was a satellite in Earth orbit where it took advantage of being outside of the atmosphere to observe the cosmic microwave background radiation that permeates the observable universe. The background radiation was first deduced by Andrew McKellar in 1941. In the 1960s two engineers at Bell Laboratories observed that it was not tied to any known celestial object. In fact, it was visible in all directions both day and night and so they concluded that its source lay beyond the boundary of our own Milky Way galaxy. For this discovery, Arno Penzias and Robert Wilson received the 1978 Nobel Prize for Physics.
The importance of the background radiation has to do with the astronomical creation theory known as the “Big Bang” in which the universe came into being from a singularity out of which started its sudden and violent growth. As the theory goes, space has continued expanding like a stretched rubber sheet ever since.
One of the predictions this theory makes is that there should be left over decaying radiation throughout the universe. Due to the expansion, this leftover radiation would be weak and very cold. The observed background radiation is about 3 degrees Kelvin. That is, only three degrees above absolute zero, the temperature at which all molecular motion due to heat ceases.
Mather’s observations of the cosmic background radiation verified its blackbody spectrum and this was interpreted as additional confirmation for the Big Bang theory. A black body is an idealized physical body that absorbs all electromagnetic radiation, regardless of frequency or direction.
Another discovery made was that the background radiation is not perfectly smooth. Rather it has anisotropy, or warmer and cooler spots scattered throughout. Astronomers interpret these spots as “primordial seeds” leading to the structure of the universe we observe today.
It was because of these findings that Mather was awarded the Nobel Prize for Physics in 2006.
Mather is scheduled to speak at the regular Oct. 10 meeting of the Westminster Astronomical Society (WASI). The meeting starts at 7:30 p.m. at the Bear Branch Nature Center (BBNC), 300 John Owings Road. The monthly meetings are always open to the public and are free. However, parking and auditorium space is limited so it is recommended that you arrive early to ensure securing a seat.
Also coming up on Saturday, Oct. 13 at 7:30 p.m. is a program in the Bear Branch Nature Center (BBNC) planetarium followed, weather permitting, by astronomical observing at the co-located B.F. Roelke Memorial Observatory. Reservations are required for the planetarium. Call 410-386-2103 to reserve your planetarium seat. Observatory observing is free and starts at 8:30 p.m.