THE BEAUTIFUL RADIATION OF THE UNIVERSE- "THE COSMIC MICROWAVE BACKGROUND"
INTRODUCTION
The Cosmic Microwave Background (CMB, CMBR), in Big Bang cosmology, is electromagnetic radiation which is a remnant from an early stage of the universe, also known as "relic radiation. The CMB is faint cosmic background radiation filling all space. It is an important source of data on the early universe because it is the oldest electromagnetic radiation in the universe, dating to the epoch of recombination. With a traditional optical telescope, the space between stars and galaxies (the background) is completely dark. However, a sufficiently sensitive radio telescope shows a faint background noise, or glow, almost isotropic, that is not associated with any star, galaxy, or other object. This glow is strongest in the microwave region of the radio spectrum. The accidental discovery of the CMB in 1965 by American radio astronomers Arno Penzias and Robert Wilson was the culmination of work initiated in the 1940s, and earned the discoverers the 1978 Nobel Prize in Physics.
CMB is landmark evidence of the Big Bang origin of the universe. When the universe was young, before the formation of stars and planets, it was denser, much hotter, and filled with a uniform glow from a white-hot fog of hydrogen plasma. As the universe expanded, both the plasma and the radiation filling it grew cooler. When the universe cooled enough, protons and electrons combined to form neutral hydrogen atoms. Unlike the uncombined protons and electrons, these newly conceived atoms could not scatter the thermal radiation by Thomson scattering, and so the universe became transparent instead of being an opaque fog. Cosmologists refer to the time period when neutral atoms first formed as the recombination epoch, and the event shortly afterwards when photons started to travel freely through space rather than constantly being scattered by electrons and protons in plasma is referred to as photon decoupling. The photons that existed at the time of photon decoupling have been propagating ever since, though growing fainter and less energetic, since the expansion of space causes their wavelength to increase over time (and wavelength is inversely proportional to energy according to Planck's relation). This is the source of the alternative term relic radiation. The surface of last scattering refers to the set of points in space at the right distance from us so that we are now receiving photons originally emitted from those points at the time of photon decoupling.
Why to study CMB?����This study is important because this is the only radiation we know till date which is of the same age as of the universe, i.e 13.81 billion years & hence giving it the name "First Light".�It is important to know more about the cosmos, and to find out how the universe begin, at what temperature did the giant explosion took place, how was the universe in the past and what will be its image in the future, because glow of the first light is present in all directions throughout the universe. It is special because, it is present across the globe too!!���
What does it do?
The entire sky is a source of microwaves in every direction and its presence can be felt when we deal with modern technology, for example in point-to-point communication links, wireless networks, microwave radio relay networks, radar, satellite and spacecraft communication, medical diathermy and cancer treatment, remote sensing, radio astronomy, particle accelerators, spectroscopy and many more.��
Wilkinson Microwave Anisotropy Probe (WMAP)
What is WMAP?�
The Wilkinson Microwave Anisotropy Probe (WMAP) is a NASA Explorer mission that launched June 2001 to make fundamental measurements of cosmology -- the study of the properties of our universe as a whole. WMAP has been stunningly successful, producing our new Standard Model of Cosmology. WMAP's measurements played a key role in establishing the current Standard Model of Cosmology: the Lambda-CDM model. The WMAP data are very well fit by a universe that is dominated by dark energy in the form of a cosmological constant. Other cosmological data are also consistent, and together tightly constrain the Model. In the Lambda-CDM model of the universe, the age of the universe is 13.772±0.059 billion years. The WMAP mission's determination of the age of the universe is to better than 1% precision.
The universe comprises only 4.6% atoms. A much greater fraction, 24% of the universe, is a different kind of matter that has gravity but does not emit any light --- called "dark matter". The biggest fraction of the current composition of the universe, 71%, is a source of anti-gravity (sometimes called "dark energy") that is driving an acceleration of the expansion of the universe.�WMAP has also provided the timing of epoch when the first stars began to shine, when the universe was about 400 million old. The upcoming James Webb Space Telescope is specifically designed to study that period that has added its signature to the WMAP observations.�WMAP launched on June 30, 2001 and maneuvered to its observing station near the "second Lagrange point" of the Earth-Sun system, a million miles from Earth in the direction opposite the sun. From there, WMAP scanned the heavens, mapping out tiny temperature fluctuations across the full sky. The first results were issued in February 2003, with major updates in 2005, 2007, 2009, 2011, and 2013. The mission was selected by NASA in 1996, the result of an open competition held in 1995. It was confirmed for development in 1997 and was built and ready for launch only four years later, on-schedule and on-budget.�
Components of WMAP
How does it work?
On board WMAP were two main types of instruments: optics, which focus the incoming radiation, and radiometers, which amplify and convert the microwave signal into something that can be measured and transmitted back to Earth. During each six-month orbit, WMAP took one complete picture of the sky. From this data, which was refined during each orbit, scientists got clues about the nature of the universe and its origins. Microwave radiation or Relic radiation is the part of the electromagnetic spectrum and its wavelength varies from 1mm to 1m and its frequency lies in the band of 300GHz to 300MHz. Heat between a source and a recipient can be transferred in three different ways: conduction, when the two are in direct contact, similar to when you touch a hot glass; convection, when the heat is exchanged by a medium, generally fluid, similar to when hot air contacts colder air; lastly, radiation, when the heat is exchanged by the means of an electromagnetic wave, which requires no medium to spread, for example, the warmth conferred by the sun’s light that travelled millions of miles through void(empty) space.
This is the only radiation present in the background of the cosmos which gives us an insight about the initial and present temperature of the universe.
As time passes the presence of CMB is declining and the temperature is gradually falling down. According to research when the universe was in a compact stage and all of the microwave radiation was confined within a small space its the initial temperature was 1 billion degrees or 109 K and the present temperature of the universe when the microwave is not confined and spread over a large infinite area is approximately 2.73 kelvin. So, we can say that microwave radiation is helpful in preserving the temperature of the universe.
How I Developed This Project?�
This topic was chosen because it was interesting and researching about this topic gave a brief knowledge and information about the formation, temperature & initial stage of the universe. By researching about this topic i came across several interesting and astonishing facts and figures which gave me the base to start and understand several derivation and constants. It gave rise to several mind twisting thoughts and questions which were fun to solve.
The approach to developing this project was a hardcore research and combining the 9 years data to form a single output about the Relic Radiation provided by the Wilkinson Microwave Anisotropy Probe (WMAP).
No such coding language was used neither any special hardware or software were used in this project. This project is a research based project which do not indulge the use of any coding language, hardware or software.
No as such major problems were faced during the research work and obtained very high quality results about the topic. After completing the research and study we were able to understand the concrete value of Hubble constant, Baryon Density, Cold Dark Matter Density, Physical Baryon Density, Physical Dark Energy Density, Density Fluctuations, Scalar Spectral Index, Reionization Optical Depth, Curvature of the Universe, Tensor to Scalar Ratio, Running Scalar Spectral Index, the hint how the universe begin and probably how will it end, when will the temperature drop to absolute zero.
How I Used Space Agency Data in This Project�
For reference, we considered the data for our research work from https://map.gsfc.nasa.gov/. We used open data too and combined the data which we obtained from the official website and made an suitable output.
The official data was used in my research work very actively and effectively to finalize the data and make a concrete output with minimum errors.
Achievements and Results
Sources & References
Thankyou
By- Suryansh Saxena
Department- Electronics & Communication Engineering
Jaypee institute of information technology, India