Echo of the Universe
Imagine Earth at the center of the sphere. Cosmic microwaves coming to us from every direction in the sky provide a snapshot of the young universe, which was filled with a clotted fluid made of dark and visible matter. (Image Courtesy-Quanta Magazine)
Isn’t it amazing how accidents lead to unraveling of the fibres of the universe?
One such accident that led to the model of the universe as predicted by Friedmann, was that of Arno A. Penzias and Robert W. Wilson.
If you scroll down to our previous articles, we talked about Friedmann’s models of the universe and the assumptions it was based upon.
One of those assumptions is that the universe is identical in whichever direction we observe. This assumption was proved after 40 years by Penzias and Wilson.
Unaware and incognizant, The two American radio astronomers would have never imagined that they were on the verge of making a brilliant discovery in the field of cosmology which was, the discovery of the Cosmic Microwave Background radiation (CMB) or how I like to call it “The Echo of the Universe”.
This is also known as the ancient light that began to exist in the universe nearly 378,000 years after the Big Bang.
The Holmdel Horn Antenna at Bell Labs in New Jersey detected a buzzing that seemed to be coming from all parts of the sky. Stumped and puzzled, Penzias and Wilson thought it to be the interference caused by the pigeon droppings that covered the antenna equipment and it wasn’t until after the pigeons were trapped and the antenna was cleaned that they eliminated every possible source of interference after which they concluded this was a “signal”.
Regardless of the direction at which they pointed the detector, it was the same day and night throughout the year, so the rotation and revolution didn’t affect the signals. This helped them rule out the possibility that the signal must be coming from the atmosphere. They also knew that any noise from within the atmosphere would be stronger when the detector is not pointing straight up than when it is. This factor was because the atmosphere is thicker at an angle to the vertical than anywhere else. Thus making this a signal that came from beyond our known horizons. This signal is postulated to have been existing since the Recombination Era; when the Universe cooled from the state of hot, dense, opaque plasma with matter and energy all in one place to 2700° C, a temperature cool enough for electrons and protons to “recombine” and photons escaped in form of the radiation now known as CMB. Today the CMB is very cold and just 2.725° above absolute zero and thus visible in the microwave region. The discovery was indeed big as it unveiled the origins of our Universe as we know it suggesting that the cosmos did indeed grow from a tiny seed, a singularity that was infinitely dense and at a timespan of about 13.8 billion years ago, henceforth concluding the clash between the Big Bang Theory and the Steady State Theory which held that matter was being constantly created with the expanding universe without making compromises with the overall density and that the universe had existed forever.
Not only does the discovery of CMB prove the Big Bang Theory but also lends support to the Cosmic Inflation theory which states that the "universe expanded much faster than speed of light just after a few tiny seconds after Big Bang”
Coming back to how Penzias and Wilson theorized this discovery to be the proof of Big Bang theory, they said that if the Big Bang was correct, then the universe would be filled with CMB left over from the creation event and that this radiation would cover the sky uniformly in every direction. CMB also tells about the tiny variations in temperature and density which give rise to formation of stars and galaxies and all other structures of the universe that are known to mankind.
Not only does CMB take us back to the origins of the universe but it also tells us about the composition of the universe as a whole.
It is quite intriguing to state again that normal matter, which makes up everything we can see such as stars, galaxies and trees on earth only makes up for about 5 percent of the universe.
Scientists have extracted very vital information from the CMB which has untwirled the fibres of the universe, they have provided proofs for theories like Big Bang and Cosmic Inflation which help us to understand our universe’s past and probably the future too.
Stick with us and follow our blogs for more interesting articles from the realm of astrophysics today!
-By Muhammad Umair Ansari
REFERENCES:
The Theory of Everything- Stephen Hawking
Comments