Planck Mission Finds Universe a Bit Older, Still Mysterious
The European Space Agency’s Planck mission is revealing new details about the early universe, prompting scientists to revise estimates for the age, makeup, material consistency and expansion of the cosmos following the Big Bang.
The European space telescope was launched in 2009 to carry out an “all sky” survey of the faint traces of light emitted after the massive explosion with greater precision than NASA’s pioneering Wilkinson Microwave Anisotropy Probe (WMAP) and the Cosmic Background Explorer (COBE) missions, launched respectively in 2001 and 1989.
Planck’s latest findings are prompting a change in the Hubble constant, a calculation of the expansion rate of the universe. The new calculation, 67.15 kilometers/second/mega parsec, is significantly less than the current standard value in astronomy established with the help of the Hubble Space Telescope. A mega parsec is about three million light-years. The change increases the latest estimate for the age of the universe from 13.7 to 13.8 billion years.
The European-led mission also finds more normal matter and dark matter than previous estimates. The first is the lineup of atoms in the Periodic Table that make up all of the familiar stuff in our surroundings. Dark matter is the mysterious material that holds large star systems, like the Milky Way together, with its gravity.
There is apparently now less dark energy than thought earlier. Dark energy, a force opposite that of gravity, is causing the universe to expand. An understanding of its workings is among the highest priorities in physics.
“Astronomers worldwide have been on the edge of their seats waiting for this map,” said Joan Centrella, Planck program scientist at NASA Headquarters in Washington, in a statement that accompanied the European announcement.
NASA made mission enabling contributions to the two observing instruments aboard Planck that mapped the sky in nine frequencies to chart the Cosmic Microwave Background. Radiance from the CMB emerged an estimated 370,000 years after the Big Bang, a point at which temperatures cooled enough to permit the pairings of electrons and protons to form hydrogen — fuel for the first stars.
U. S.and Canadian scientists are working with European experts to interpret the CMB imagery.
The map, based on the Planck mission’s first 15.5 months of all-sky observations, reveals tiny temperature fluctuations in the cosmic radiance that has traveled for billions of years from the very early universe to reach the spacecraft.
The patterns of light represent the seeds of galaxies and clusters of galaxies we see around us today. According to the Standard Model of Cosmology, the fluctuations arose immediately after the Big Bang and were stretched to cosmologically large scales during a brief period of accelerated expansion known as inflation. Planck was designed to map these fluctuations across the whole sky with greater resolution and sensitivity than ever before.
By analyzing the nature and distribution of the seeds in Planck’s CMB image, experts can determine the composition and evolution of the universe from its birth to the present day.
“As that ancient light travels to us, matter acts like an obstacle course getting in its way and changing the patterns slightly,” said Charles Lawrence, the U.S. project scientist for Planck at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. ”The Planck map reveals not only the very young universe, but also matter, including dark matter, everywhere in the universe.”
While scientists anticipated great symmetry, or evenness, in what Planck observed across the sky, they are finding puzzling fluctuations, including a vast “cold spot” that may challenge some physical assumptions. Planck findings are also testing theories of “inflation,” the vast expansion of the universe immediately after its birth.
“In far less time than it takes to blink an eye, the universe blew up by 100 trillion trillion times in size,” NASA explains in a statement on the latest findings. “The new map, by showing that matter seems to be distributed randomly, suggests that random processes were at play in the very early universe on minute “quantum” scales. This allows scientists to rule out many complex inflation theories in favor of simple ones.”
The CMB was discovered in 1962 by a pair of scientists, Arno Penzias and Robert Wilson, at Bell Laboratories inNew Jersey. The discovery, made by accident, was further explained by Princeton University scientist Robert Dicke. Penzias and Wilson were awarded the Nobel Prize for physics for their work in 1978.