Einstein’s theory holds good after 100 years

Albert Einstein, considered the greatest modern scientist after Isaac Newton, wrote his breakthrough paper about the general theory of relativity in 1915, in which he posited that there was a curvature in space-time caused by gravity.

This was first tested during the solar eclipse of 1919 which showed that starlight bent as it travelled past the Sun. This was detected during the precession – the rotation of a planet around the Sun – of Mercury. There have been several other confirmations through observations of astronomical events over the years. The latest data was collected through observations of Dark Energy Spectroscopic Instrument (DESI) at Kitt Peak National Laboratory, Arizona, in the United States. The observations ranged across five thousand galaxies simultaneously.

The data revealed that the structure of the galaxies, clusters of galaxies including super-clusters was formed following the presence of gravitation as a force which held them together. This was announced by the scientists involved in the research on Tuesday.

The structure of the cosmos comprising the galaxies dated to one-fifth the 13.8 billion years since the Big Bang. That is, around 11 billion years ago. But the DESI researchers found that the dark energy driving the expansion of the universe is a dynamic force. Therefore it cannot be said that the universe will continuously expand.

Said co-leader of DESI team and astrophysicist Mustapha Ishak-Boushaki, “Our DESI data shows that it is in agreement with Einstein’s theory of gravity but still favours a dynamical dark energy – and finding these simultaneously is new.”

Ishak-Boushaki explained the fallout of the discovery of the dynamical dark energy: “Dark energy seems to be dynamical and weakening. That changes the future of the evolution of the universe, which does not need to be accelerating forever in its expansion.” He said, “The strong hint that dark energy is dynamical is the most important finding since the discovery of cosmic acceleration in 1998.”

The other co-leader of the DESI team, University of Michigan cosmologist Dragan Huterer, felt that the dynamical nature of the dark energy raised the prospect of modifying Einstein’s theory of gravity. But that data showed that the structures of the galaxies showed that Einstein’s position on gravity held good. Huterer said, “Dark energy is responsible for the accelerated expansion of the universe. The physical nature of dark energy is at present unknown.”

It is interesting that of the two scientists, Mustapha Ishak-Boushaki seem to be holding different views. While Ishak-Boushaki says that the dynamical energy is weakening, Huterer says that the nature of the physical nature of the dark energy remains unknown. They do not contradict each other. They are explaining the different aspects of dark energy that is dynamical. What Huterer says is true: “Verifying whether the standard model is indeed the correct model is at the forefront of cosmology research.”

Huterer as a cosmologist is looking at the larger theory of the universe or cosmos, while Ishak-Boushaki as an astro-physicist is looking for the verification of known physical laws – in this instance, Einstein’s General Theory of Relativity — and the behaviour of the dark energy as reflected in the data. Huterer is probing the cause of dark energy as it were.

Many people believe that science is a monolith, and if some law is true, the other laws posited earlier become outdated or fall by the wayside. Modern scientists, especially physicists and cosmologists, are discovering that the universe is governed by many physical laws. For anyone looking for pure logic, the plurality of laws would appear contradictory. But it seems that the universe transcends pure logic. It exists as a many-splendoured thing as described by the poet.