"About 14 billion years ago, a giant explosion threw matter around in all directions. With a bang, the universe was born. At least, that is what most scientists agree happened. This explanation of how the universe began is known as the big-bang theory.
Though widely accepted, the big-bang theory is hard to prove with 100 percent certainty. NASA's John Mather likes a challenge, so he thought he'd give it a shot. In 1974, he [John Mather] proposed a satellite mission to gather proof for the hard-to-prove theory. Now, more than 30 years later, he is being rewarded for his work." John Mather received the Nobel Prize for Physics in 2006. Mather and his team started building the satellite, named COBE, in 1982. COBE is short for the Cosmic Background Explorer. The satellite was launched in 1989 and has allowed scientists to measure the cosmic radiation throughout the universe.
According to the NASA web page: "Back in 1929, Edwin Hubble discovered that distant galaxies were traveling away from Earth at tremendous speeds. This movement showed that the universe is expanding. Scientists then suggested the big bang as a way to explain why galaxies would be moving away. The theory also predicted that the universe is filled with leftover radiation from the original explosion. A little more than 40 years ago, two scientists accidentally discovered this radiation, which cannot be seen with human eyes. It's called the cosmic microwave background radiation, because it emits waves of energy in the microwave portion of the electromagnetic spectrum. This discovery was the first strong evidence for the big bang, and won those two scientists a Nobel Prize in 1978."
The COBE team and other scientists have been looking for proof to not only explain why the universe is expanding, but to also verify that the Big Bang started it all and that the microwave background radiation can be measured and mapped.
Below is a COBE image of the cosmic microwave background radiation. The pink and blue colors show tiny fluctuations in the temperature of the radiation.
This week it was announced by the Harvard-Smithsonian Center for Astrophysics that they have found new proof of inflation, which then supports the Big Bang Theory. On the web page http://www.cfa.harvard.edu/news/2014-05, the team described their accomplishment:
"Almost 14 billion years ago, the universe we inhabit burst into existence in an extraordinary event that initiated the Big Bang. In the first fleeting fraction of a second, the universe expanded exponentially....Researchers from the BICEP2 collaboration announced the first direct evidence for this cosmic inflation. Their data also represent the first images of gravitational waves, or ripples in space-time. These waves have been described as the "first tremors of the Big Bang." Finally, the data confirm a deep connection between quantum mechanics and general relativity."
The ripples are shown in this BICEP2 Collaboration image:
According to the team's announcement:
"This has been like looking for a needle in a haystack, but instead we found a crowbar....
When asked to comment on the implications of this discovery, Harvard theorist Avi Loeb said, "This work offers new insights into some of our most basic questions: Why do we exist? How did the universe begin? These results are not only a smoking gun for inflation, they also tell us when inflation took place and how powerful the process was."
The team's South Pole station is shown below.
The tiny temperature fluctuations of the cosmic microwave background (shown below in this BICEP2 Collaboration color image) trace primordial density fluctuations in the early universe that seed the later growth of galaxies.