The slight variances in the temperature of the cosmic microwave background radiation as seen by the European Space Agency's Planck spacecraft. Leftover light from the Big Bang stretched into microwave wavelengths over cosmic history. (Image Credit: ESA/Planck)
The cosmic microwave background (CMB) is the oldest detectable light in the universe. This light fills the sky as a faint glow in the radio portion of the electromagnetic spectrum, peaking in the microwave frequency range. The CMB is thus invisible to the human eye, but scientists can study it using instruments sensitive to microwaves. The CMB is often referred to as the relic radiation, or afterglow, of the Big Bang, the event that began the universe 13.8 billion years ago. The CMB itself was generated about 378,000 years after the Big Bang during an epoch called "recombination." After the cosmos had cooled from its initially infernal temperatures to about 5,000 degrees Fahrenheit, the elementary particles of protons and electrons that were forged in the Big Bang joined to form hydrogen atoms. This recombination released photons, or particles of light, that now stream toward us from every direction. Analysis of the CMB has enabled researchers to estimate the universe's age as well as its composition of 68 percent dark energy, 27 percent dark matter and 5 percent "normal," everyday matter. Furthermore, the temperature variations and other detailed properties of the CMB speak to the universe's earliest development, including the possibility that it underwent a rapid period of expansion known as inflation.
Three principal researchers at the Laser Interferometer Gravitational-Wave Observatory (LIGO)—Nergis Mavalvala, Rainer Weiss and Matthew Evans—reflect on the epic discovery of gravitational waves and how it will transform the way we see the cosmos.
The most accepted idea for how the early universe behaved, cosmic inflation, remains more an abstraction than full-fledged theory. During a live Google Hangout, three preeminent scientists considered the evidence for and against this contentious concept.
The latest data release from the Planck space telescope offers insight into everything from the fabric of space to dark matter – and may even have a shot at detecting gravitational waves, says Kavli Institute for Cosmology Director George Efstathiou.
ON FEBRUARY 18, 2015 three preeminent scientists came together to discuss the latest results, what they mean for the theory of inflation, and what we can expect to learn about the very early universe in the coming decade.
The winners of the 2014 Kavli Prize in Astrophysics – Alan Guth, Andrei Linde and Alexei Starobinsky – discuss their development of the theory of inflation and reflect on how it has changed our view of the universe.
Scientists have announced we may now have the first “smoking gun” evidence that the universe expanded with unmatchable speed in its earliest moments. Three theoretical physics consider the implications of this stunning development.
SLAC and Stanford scientists, many from the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), are at the center of the exciting new results of cosmic inflation and will be holding a special colloquium to celebrate on Wednesday, March 19 from 3:00-5:30pm PDT on the SLAC campus.