The earliest snapshot of the universe. Photo Credit: ESA/Nasa
New Delhi, March 21: An international space mission today released the most detailed and earliest snapshot of the universe, which has bolstered the evidence for current cosmology theories but revealed some mystery features that scientists cannot yet explain.
Three Indian researchers were among dozens worldwide who analysed data from instruments aboard a European spacecraft to generate images of the universe about 380,000 years after its moment of origin, the Big Bang.
The instruments have helped scientists create the most detailed map of what astronomers call the cosmic microwave background radiation (CMBR), the residual afterglow left behind by the Big Bang. The map (see photo) shows tiny fluctuations in temperatures that scientists say served as “cosmic seeds” that have evolved into the large structures of the universe observed today: galaxies and clusters of galaxies.
“The picture tells us that our current understanding of the universe is very good,” said Sanjit Mitra, a scientist at the Inter-University Centre for Astronomy and Astrophysics, Pune, and a member of the research team.
The instruments aboard the European Space Agency’s Planck spacecraft are designed to measure temperature fluctuations at a precision never achieved before. The map generated from the observations suggests the universe is about 13.8 billion years old, or 100 million years older than previous estimates, US agency Nasa said.
But scientists say some of the features observed cannot be explained by current theories. One of these is a pattern called hemisphere asymmetry: the fluctuations are expected to be uniform across the sky but the data suggest the patterns are asymmetrical on the two halves of the sky.
“Imagine a football field full of people wearing red and blue. Our existing theories suggest they should be uniformly distributed on both sides of the field, but what we see is a little more red on one side and a little more blue on the other,” Mitra told The Telegraph. “This is hemispheric asymmetry, something we need to understand.”
Mitra and his colleagues, faculty member Tarun Souradeep and research scholar Aditya Rotti at the Pune institute participated in the Planck analysis, using software to build sharper images of sections of the sky.
The CMBR, the leftover heat from the Big Bang, corresponds to a temperature of about 2.7 degrees above absolute zero (which is about minus 273°C), and is uniformly distributed across the universe with fluctuations of about 0.00001°C.
Another unexplained element from the Planck observations is a so-called “cold spot”, a low-temperature zone in the CMBR map that extends over a patch of the sky that is too large than can be explained by current theories.
“The Planck data call our attention to these anomalies.... We can no longer ignore them as mere artefacts; we must search for an explanation,” Paulo Natoli, a Planck project scientist at the University of Ferrara in Italy, said.