The team of scientists behind the European Space Agency’s Planck mission has been awarded the prestigious 2018 Gruber Cosmology Prize. NASA’s Jet Propulsion Laboratory in Pasadena, California, played a key role in the design and construction of the Planck instrument, and in the scientific analysis of the mission’s data.

The Gruber International Prize Program is sponsored by the Gruber Foundation, based at Yale University. The Cosmology Prize “honors a leading cosmologist, astronomer, astrophysicist or scientific philosopher for theoretical, analytical, conceptual or observational discoveries leading to fundamental advances in our understanding of the universe.”

Launched in 2009, the Planck satellite spent 4 years making a high-resolution map of the oldest light in the universe, the cosmic microwave background (CMB), emitted 13.8 billion years ago when the universe was only 470,000 years old, giving us a “baby picture” of the cosmos.

This map allows researchers to learn about the entire 13.8-billion-year history of the universe, including its age, rate of expansion, and the distribution of mass and energy throughout. While Planck is not the first mission to map the microwave background, it did so with unprecedented angular resolution, sensitivity, and frequency coverage, producing the most accurate and detailed CMB map ever made.

JPL is managed by Caltech, also in Pasadena. Caltech’s science and data center for astronomy, IPAC, hosted the U.S. Data Center for Planck.

“The scientific goals of Planck were highly ambitious and have been realized completely,” said Charles Lawrence of JPL, project scientist for the U.S. Planck Project. “Well over 100 people from JPL and IPAC worked on Planck over the years and contributed enabling hardware, software and analysis to the mission. We can be proud of this mission’s legacy, and the recognition of its importance by the Gruber Cosmology Prize.”

Mapping the CMB

Maps of the cosmic microwave background show the sky covered in seemingly random freckles of color. Those colors represent variations in the CMB’s temperature, which the Planck satellite could measure down to one millionth of a degree. Those incredibly subtle variations arise from quantum fluctuations in the very early universe, which develop into the large-scale distribution of matter in the universe that we see today. In addition, the light from the CMB that reaches Earth has traveled through the entire visible universe, and very massive objects, like clusters of galaxies, act like obstacles that can also change the patterns that scientists observe in the Planck data.

NASA’s Planck Project Office — which led the US contribution to the mission — was based at JPL, where scientists and engineers developed the overall thermal design concept for the mission; built the 20-K hydrogen sorption cooler system, which cooled the Low Frequency Instrument (LFI) to its operating temperature and provided precooling for the High Frequency Instrument (HFI); built the detectors for the HFI; and developed the amplifier technology for the LFI.

Engineers and scientists at IPAC are responsible for retrieving mission data from the Planck Data Processing Centers (in Paris, France and Trieste, Italy), staging data for usage by Planck team members, and for archival research by the astronomical community. The U.S. team at IPAC also generated the Early Release Compact Source Catalog (ERCSC), the first public data product from the mission.

The Planck data have provided a wealth of results for the field of cosmology, including: a refined measurement of the age of the universe, its rate of expansion and other cosmological properties; a refined estimate of when the first stars appeared; a catalog of more than 1,500 galaxy clusters (collections of multiple galaxies held together by gravity); unprecedented observations of the microwave and infrared light coming from the Milky Way galaxy; and studies of the galaxy’s magnetic fields. The results tested the most widely accepted cosmological model of the universe to high precision, and opened up new areas of study both inside and outside the Milky Way.

Planck also helped researchers take a census of the three components that make up matter and energy in the universe: “regular matter,” the kind we are made of, makes up just 4.9 percent; dark matter, detected only by the effects of its gravitational pull, makes up 26.2 percent; and dark energy, the name we give to whatever is causing the universe’s accelerated expansion, makes up 68.9 percent.

JPL scientists also played essential roles in turning the Planck measurements into all-sky CMB maps of unprecedented quality, and in the scientific analysis that led to the cosmological results recognized by the Gruber Prize.

“Planck was by far the very best instrument of its kind, like a high-performance race,” said Krzysztof Gorski, a senior research scientist at JPL. Gorski joined the Planck mission on the European side in 1996 before transferring to JPL and then joining the U.S. Planck Project in 2003.

“As it was designed to do, Planck provided complete closure on CMB temperature measurements and answered many important questions about the universe,” he said. “But it also gave us hints about even bigger questions in cosmology that we can’t fully answer yet — so it left us wondering. All of that is a priceless legacy of the Planck mission.”

The $500,000 prize will be divided between Planck’s principal investigators, Nazzareno Mandolesi and Jean-Loup Puget, and “the Planck team.” Hundreds of scientists have contributed to various aspects of the mission; a smaller group will represent the Planck team and accept the prize money. More than 300 scientists and engineers from the Planck mission, including many from JPL and IPAC, will accept the Gruber Prize at the 30th General Assembly of the International Astronomical Union in Vienna, Austria, this August.

The Gruber Prize was also awarded to two previous NASA missions that mapped the CMB: the Cosmic Background Explorer (COBE), launched in 1989, and the Wilkinson Microwave Anisotropy Probe (WMAP), launched in 2001.