2019’s prestigious Nobel Prize in Physics is claimed by three phenomenal scientists – James Peebles, Michel Mayor and Didier Queloz for groundbreaking discoveries of the Universe. This research helped us to progress in the quest to understand the development of the Universe and Earth’s place in it.
The journey of space exploration has been astonishing so far. Development from the flat earth theory to the study of other galaxy was a process of self-correction and has been astonishing. There were always some extraordinary minds who believed in extending the boundaries of knowledge.
According to the Big Bang Theory, our universe is assumed to have started from an extremely hot and dense state which is considered to be a singularity. After the expansion in the span of about 13.5 billion years, the universe we see now was created. This theory has certain evidence like galaxies that are moving apart, yet it’s not completely accepted.
At Princeton University in New Jersey in 1962, the group of Robert Dicke was working on the theory that if as predicted the universe was expanding, then there is a great possibility that it must have been smaller and denser in the past. James Peebles was a part of this group.
The prediction was that the thermal radiation from this early time of the universe might still be observable today as background radiation spread throughout the universe. The goal was to design an instrument that could detect these background radiations.
A small group of scientists in Bell Lab had found some background noise, which later became clear to be nothing but background radiation. This is now known as the cosmic microwave background (CMB) radiation. These radiations are maximum in the microwave region. These discoveries gave birth to a newly emerging field of observational cosmology.James Peebles is awarded for his contribution to theoretical discoveries in physical cosmology. In physics, theoretical discoveries are sometimes underrated, but history has proved the importance of theoretical findings from time to time. Cosmology deals with the origin, structure, and evolution of the universe.
Peebles realized the significance of the discovery of CMB(Cosmic Microwave Background). His work has mainly dealt with understanding of the beginning and evolution of structure in the universe from the primitive conditions present in a cryptic form known as CMB. In the process, he has helped define an entire field of study.
Peebles played a vital role in modeling the universe, which is today known as the standard cosmological model. It suggested the existence of mysterious dark matter and dark energy. Something which is still not fully understood but whose existence is proved by experimental observations.
He has also investigated fluctuations in the temperature of the CMB. He underlined the role played by dark matter and energy in the establishment of the universe. This helped in the understanding of the theoretical framework for the formation and evolution of the universe. He played a crucial role in the establishment of the link between CMB and various cosmological parameters.
The other half of the Nobel Prize in Physics 2019 is claimed by Michel Mayor and Didier Queloz for the discovery of an exoplanet orbiting a nearby star. An exoplanet is a planet outside our solar system. Now finding such planets is difficult for multiple reasons like stars are too bright compared to planets. It’s akin to finding a firefly in bright daylight.
In October 1995, this pair announced the discovery of an exoplanet orbiting a solar-type star. This was a revelation that forever changed our view of the Earth’s place in the universe. Since then, more than 4000 exoplanets have been discovered. Recently planet with the potential to hold life has been discovered.
There are many ways to find an exoplanet like transit method, reflection or emission modulations, etc. They used a method called the radial velocity method, which makes use of something known as the doppler effect. Doppler effect is a shift in wavelength due to the relative motion between source and observer. The information of star is gathered only through the electromagnetic waves (such as light) that they emit. The spectrum emitted from the star reveals the information like the elements contained in star.
Michel Mayor and Didier Queloz analyzed the movement of a star using the doppler effect. When a star comes towards the Earth, the spectrum shift towards blue, and the spectrum shifts towards red when it moves away from the Earth. They built a very sensitive instrument for precise measurements, which will indicate even minute changes.
Planets with their gravity pull stars towards them, though stars weigh much larger than that of planets, there is still a pull due to which a slight shift in the position of the star appears. An instrument sensitive enough to such small changes can detect such changes. In 1995, they observed in the spectrum of the star 51 Pegasi, a wobble which could only be explained by a relatively small, unseen companion — an exoplanet in orbit.
These discoveries again proved the importance of unconventional thinking, discoveries which changed the way we look at the universe.