Lehigh News Article

Menu
Looking back in time to see how it all began
Though he confessed to “leaving some parts out,” John C. Mather, winner of the 2006 Nobel Prize in physics, shared “The History of the Universe from Beginning to End” with a packed audience in the auditorium of Lewis Lab last week.

From the earliest discoveries about the universe to a daunting prediction for the earth’s distant future, Mather explained how astronomers study the universe by looking back through time.

“If you want to study the old earth, you have to find old rocks,” said Mather, who is a senior astrophysicist at NASA’s Goddard Space Flight Center.

“To study the old universe, you look at things that are far away and see them as they were when they sent light out... If we can measure the distance, we can tell how far we’re looking back in time. Now we can survey the universe and get a time scale.”

Mather spoke here on Thursday (March 27) as part of the weekly colloquium series of the department of physics.

His Nobel Prize-winning work supports The Big Bang Theory, which posits that a cosmic explosion approximately 13.8 billion years ago caused a rapid expansion of the universe that continues today.

“When we say ‘The Big Bang Theory,’ it’s not only a TV show; it’s a comprehensive, pretty complete story that explains almost everything that we’ve seen in the sky,” he said.

The beginning of the universe, Mather said, “gave us whatever we have.” Nuclear reactions between three-minute-old neutrons and protons yielded helium nuclei. When electrons latched onto these atomic nuclei, the primordial gas became transparent, allowing heat radiation to travel in straight lines. It’s been doing so ever since.

“We now can make a map by looking at the heat radiation as it was released when the gas became transparent. Suddenly the fog is clearing. Now we can see.”

“The most important scientific discovery of the century”

Mather discussed how the groundbreaking work of scientists over the past century has led to what we now know about the Big Bang. Though Albert Einstein was certain in 1916 that the universe was static, the Russian physicist Alexander Friedmann theorized the opposite—that it was, in fact, expanding. In 1929, the American astronomer Edwin Hubble supported this theory with his discovery that the farther from Earth a galaxy was, the faster it was traveling. The Hubble telescope, named in his honor and launched in 1990, gave scientists an unobstructed view of the universe, allowing them to observe hundreds of billions of galaxies.

“In 1985, we had many confident predictions which were almost all incorrect, and so we found that out when we watched the Hubble Space Telescope,” Mather said.

Mather’s work as project scientist for NASA’s Cosmic Background Explorer (COBE) satellite, which was launched in 1989, provided more evidence. Designed to measure cosmic heat from the early universe, COBE enabled Mather and his team to test the expanding universe theory. The results confirmed the Big Bang by showing that the cosmic microwave background radiation has a blackbody spectrum.

They also discovered hot and cold spots in the early universe called cosmic anisotropy. These spots, Mather said, “must exist for us to be here. This is what the force of gravity required to act upon so that galaxies could be formed.”

This research earned Mather and his colleague George Smoot the 2006 Nobel Prize in Physics, as well as high praise from Stephen Hawking, the English theoretical physicist and bestselling author, who called their work “the most important scientific discovery of the century, if not of all time.”

Mather’s work with COBE also led to his book, The Very First Light: The True Inside Story of the Scientific Journey Back to the Dawn of the Universe (Basic Books, 2008).

A future encounter with a neighboring galaxy

Mather discussed the recent work of astronomers at the South Pole, which detected evidence of sound waves of several types in the early universe. This discovery suggests that there are imprints of the polarization of cosmic microwave radiation, patterns that come from the very first fractions of a second.

“If true,” Mather said, “it confirms one of the most astonishing ideas that we’ve ever had, which is that the universe in the first trillionth of a trillionth of a trillionth of a second [began] expanding exponentially, doubling in size about a hundred times in those first few seconds.”

Mather now serves as senior project scientist for the James Webb Space Telescope (JWST), which will use infrared light to explore the first galaxies to form after the Big Bang and will perhaps even probe the origin of life.

Light from the first galaxies, Mather said, has been “redshifted” from the visible into the infrared. The next-generation JWST, scheduled to launch in 2018, is the product of international collaboration and innovative design. When it is in place nearly a million miles from the earth, the JWST will be the premier space observatory for astronomers worldwide.

Unfortunately for the earth’s inhabitants, Mather said, recent studies have found that as the universe continues to expand outwards, the nearest spiral galaxy, Andromeda nebula, will collide with the Milky Way. However, scientists expect the collision will not occur for nearly two billion years.

“The Milky Way will no longer be the spiral galaxy with a neighbor. It will be something completely different,” Mather said.

In the meantime, Mather continues to search for answers and to support the next generation of cosmologists and applied scientists. He funded the John and Jane Mather Foundation for Science and the Arts with his Nobel award. Andrew Abraham, a Ph.D. candidate in mechanical engineering at Lehigh and recipient of the John Mather Nobel Scholarship, met Mather while interning at the Goddard Space Flight Center. Mather’s work has inspired Abraham, and the man himself has also made an impression.

“He’s one of the most intelligent people I’ve ever met,” said Abraham, “but you can see that he’s actually very modest. He’s the first guy to tell you that yes, he won the Nobel Prize, but there was an army of other people around him that helped him.”




Photos by Christa Neu