Einstein in the 21st Century: Our Changing Understanding of His Theories

By Bhavya Surapaneni

Castle Pines, Colorado

Albert Einstein. (Getty Images)

Albert Einstein, a German theoretical physicist who lived and worked in the late 19th and early 20th centuries, is widely renowned as one of the most influential physicists and scientists of all time. Widely known for his Quantum Theory of Light, Special and General Theories of Relativity, and numerous others, Einstein’s influence is seen every day in science classrooms and laboratories around the world. In the 21st century, scientific research has continued to work towards finding evidence of the accuracy of Einstein’s theories. In 2021 and 2022, scientists nationwide and worldwide have performed numerous experiments that have brought light to the accuracies and questions of Einstein’s postulates.

Einstein’s String Theory claims that reality is composed of minuscule vibrating strings that make up tiny dimensions, which humans see in the form of larger-scale phenomena such as gravity. In early 2021, 3 physicists—Portuguese physicist Pedro Vieira, Andrea Guerrieri of Israel, and João Penedones of Switzerland—calculated a number correlated to the quantum nature of gravity, and the number was close to the predicted number by String Theory. This number, alpha (⍺), is a term in gravity equations that Einstein created, and it’s only been determined for 10-dimensional universes in the past, but by applying a new method called ‘bootstrap’, Vieira, Guerrieri, and Penedones were able to calculate the number in a more applicable context. As a whole, String Theory lacks experimental evidence, so this new discovery represents a major shift in how physicists regard the validity of the theory.

In July 2021, a black hole observation by Stanford astrophysicist Dan Wilkins marked the first detection of light from behind a black hole. The theoretical possibility of light bending around a black hole has existed, but this observation was the first evidence found of the phenomenon. According to Wilkins, black holes warp space, thus bending light and allowing us to see light behind a black hole. According to Roger Blandford, a Physics Professor at Stanford University, viewing this occurrence means that we are seeing “Einstein’s theory of general relativity in action,” something that many astrophysicists thought humans would never have the capability to see.

In the last month of 2021, an international team utilized telescopes worldwide to complete rigorous tests on Einstein’s theory of general relativity, and their findings demonstrated that Einstein’s 1915 hypothesis still holds validity today. In order to complete these tests, the team used observations of the ‘double pulsar’ system, which comprises two highly magnetized rotating neutron stars that emit electromagnetic radiation, known as pulsars. Using ‘clock ticks’ from the pulsars, the physicists were able to detect ripples that affect accelerations of the system—these ripples are evidence of general relativity, as they strain the fabric of space-time. After 16 years of collecting 20 billion ‘clock ticks’ from the pulsar system, as well as incorporating data from a global telescope network, the team found that there was a slight change in star positions every year, which the researchers then used to find the distance of the pulsars to Earth. Einstein’s general relativity theory held true under this challenging experiment.

Most recently, in February 2022, an effect of general relativity known as time dilation was measured at the smallest scale thus far by JILA Atomic Clocks, a joint project between the University of Colorado at Boulder and the National Institute of Standards and Technology (NIST). The experiment showed that two clocks just a millimeter apart tick at different rates and they demonstrate how we can further demonstrate general relativity in the future by making atomic clocks fifty times more precise. Thus, these new clocks allow quantum mechanics to be explored and understood in curved space-time. According to NIST fellow Jun Ye, this discovery has opened pathways for physicists to find the link between quantum physics and gravity.

In a world where science is at the forefront of progress, evidence supporting Einstein’s century-old theories of General Relativity and String theory hold more importance and more implications than ever before.