THE CHALLENGE
For decades, scientists thought they knew how the universe had started. They hypothesized that the cosmos had expanded from a minuscule, dense collection of energy, and expanded in the big bang, hence the name, big bang theory, which was first presented in 1949.
That bang, they thought, left remnants of particles and radiation in space, known as cosmic microwave background, which, if definitively measured, could prove the theory was true.
Cosmic microwave background was first detected in 1964, but they didn’t know how to measure it.
“We didn’t know what it was, or whether it would have the properties to explain the universe we live in. Our job was to find out more about it, as much as possible,” said John Mather, Hertz Fellow and Nobel Prize winner.
The solution
Mather, with the support of a Hertz Fellowship, dedicated his graduate thesis project in such an attempt, using a balloon-borne instrument. It didn’t work, but it served as a prototype for subsequent ones that did. In 1974, when NASA issued a call for satellite mission proposals, Mather and six colleagues put forth a proposal that built upon his original idea.
That led him to join NASA’s Cosmic Background Explorer Satellite (COBE) project, in which Mather and the COBE team, which used the satellite to measure the heat radiation from the big bang, gave the world its first precision, all-sky map of the cosmic microwave background in 1992.
“We didn’t know what it was, or whether it would have the properties to explain the universe we live in. Our job was to find out more about it, and as much as possible.”
John Mather
Senior Astrophysicist and Goddard Fellow, NASA
The impact
Not only did Mather help to unlock a major mystery of the big bang, but the COBE mission ushered cosmologists into a new era of precision measurements. That helped eliminate incorrect theories about the big bang. It also paved the way for deeper exploration of the microwave background, first by NASA’s Wilkinson Microwave Anisotropy Probe mission, and then by the European Space Agency’s Planck mission.
In 2006, Mather and George F. Smoot received the Nobel Prize in physics “for their discovery of the blackbody form and anisotropy of the cosmic microwave background radiation.”
A New Era of Precision
The COBE mission ushered cosmologists into a new era of precision measurements.
The preciseness helped eliminate erroneous theories about the Big Bang. The mission also paved the way for deeper exploration of the microwave background, first by NASA’s Wilkinson Microwave Anisotropy Probe mission and most recently by the European Space Agency’s Planck mission.
In 2018, the Planck mission measured the cosmic microwave background to an unprecedented accuracy, providing the most detailed image yet of the universe as it appeared in its early history, just 380,000 years after the Big Bang.
At the time, researchers believed that the cosmos had expanded from a minuscule dense collection of energy, known as the Big Bang, which led to the universe as we know it. That bang, they theorized, left a remnant of particles and radiation in space known as cosmic microwave background that, if definitively measured, could prove the theory as true. But uncertainty was pervasive.
