What is Astrophysics?

what is astrophysics
© Merzavka

Daniele Malafarina, Associate Professor from Nazarbayev University, School of Sciences and Humanities, unpacks astrophysics for us in this insightful article

For most of history, looking at the cosmos was done with the naked eye, without instruments, and the main purpose of observations were to keep track of the movements of celestial bodies. Astronomy did not tell us anything about the nature of the objects being observed, namely the stars and planets.

Since the time of Galileo, Newton, Kepler, and other pioneers of the scientific revolution, we started looking at the cosmos using instruments and applying the laws of physics to make sense of what the instruments measure. This allowed us to understand what astronomical objects are, how they form and evolve, and this is the core of what astrophysics is: Using the laws of physics applied to observations of phenomena in the universe to understand their nature and evolution.

what is astrophysics
Space observatory on summit of mauna kea

Astrophysics discovery

The use of tools from physics applied to the cosmos and the development of better and better telescopes and instruments has completely revolutionised our understanding of the universe and our place in it. We discovered new planets in the solar system; Uranus in 1781, and Neptune, predicted theoretically in 1845 and discovered in 1846. We discovered new objects such as comets, dwarf planets, moons and asteroids. In the process, we learned how the solar system formed and evolved.

We discovered new kinds of stars, such as white dwarfs and neutron stars, and planets orbiting other stars. In the process, we learned how stars form and evolve over time and how other planetary systems may develop the conditions suitable for the appearance of life.

We discovered that there are other galaxies besides our own and that the universe is expanding. We also learned how big the universe is and how it all started from an extremely small, hot, and dense initial state.

Expanding our view of the cosmos

In the last hundred years, astrophysics has expanded our view of the cosmos together with our tools to investigate it. At the beginning of the 20th century, astronomers could rely only on visible light to study the universe. Today, we look at phenomena through several carriers of information like gravitational waves, different electromagnetic wavelengths, such as x-rays and gamma rays, and particles, such as neutrinos and protons.

Astrophysics has grown into a diverse and multi-facet field, addressing some of the most fundamental questions of mankind including:

  • How the first stars and structures in the universe formed several hundred million years after the big bang.
  • How gravity behaves to produce black holes, probably the most extreme objects in the universe.
  • How planetary systems form and what conditions could lead to the formation of life.

But why do we study such things? At first glance, it may seem that answering these questions has no impact on everyday life. When one thinks about astrophysics, the first impression may be that it is research done out of curiosity about the universe with no practical relevance. This is not true as astrophysics and the study of the cosmos has produced permanent changes in our society, both from the practical as well as cultural point of view.

A few practical tools that would not exist without astrophysics include CCD cameras, which are found in every smartphone but were first developed for telescopes, and the GPS system we rely upon when travelling requires the laws of General Relativity to work accurately. Also, some non-invasive methods for detecting tumours rely on sensors adapted from radio wave astronomical instruments.

This is called technology transfer and is the reason why governments and many prominent industries in the world invest in research in astronomy. Technologies developed for scientific purposes eventually find application in everyday life.

Astrophysics influences cultural changes

Astrophysics has also influenced cultural changes that have impacted our society: The discovery that the Earth is not the centre of the universe helped us realise that we are just one part of a larger system. Also, the first image of the Earth seen from space emphasised that we all live on the same small planet, drifting alone in the vastness of space and gave some people the sense of belonging to this planet rather than to a specific country.

The discovery of extrasolar planets helped us understand that there may be other inhabited worlds in the galaxy and the search for life outside Earth is helping us to understand how our own evolution happened and where some of our behavioural traits come from.

This is all part of our cultural evolution, a necessary prerequisite for a dynamic, healthy, and thriving society. Our understanding of the planetary formation, the appearance of life, and the evolution of the universe has changed the way we see ourselves as a species. That change is still ongoing, and it is part of a necessary process if we wish to depart from the constraints of our evolutionary past and become a more peaceful, self-determined, and hopefully multi-planetary species.

Human evolution as a journey

If we look at human evolution as a journey, we can expect the next steps to be uncertain, as they may lead to improvement or worsening of the living conditions for mankind. However, what is certain is that we cannot stay still and must try to move forward. A better scientific understanding of what is around us is necessary to make the best decisions for the future of mankind. This understanding cannot be limited to a short time span. We need to look further at where humanity can be in 100 or 1,000 years.

While it is important that people work on developing technologies to address today’s problems, it is also important to look beyond and lay the foundations for technologies, ideologies and objectives of future generations. Fundamental sciences like astrophysics serve this purpose.

Contributor Profile

Associate Professor, School of Sciences and Humanities
Nazarbayev University
Phone: +7 7172 69 46 61
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