X-ray Insights :Revealing Your Universe’s Hottest Cosmic Phenomena

Team Udayavani, Dec 28, 2023, 11:01 AM IST

ASTRONOMERS USE A VARIETY OF LIGHT FORMS to unravel the mysteries of the universe. Among these, X-rays play a crucial role. These are high-energy lights with wavelengths about 40 times smaller than the shortest light visible to human eyes. Originating from gases heated to millions of degrees, X-rays offer a window into the most intense regions of space—such as black holes, neutron stars and colliding galaxies.

X-RAY VIS –A VIS VISIBLE LIGHT

X-rays and visible light are parts of the electromagnetic spectrum but have different wavelengths and energies. X-rays have shorter wavelengths, around 0.01 to 10 nanometers, and higher energy. In contrast, visible light, the type we see, has longer wavelengths ranging from about 380 to 750 nanometers and less energy. This difference in wavelength and energy makes X-rays suitable for penetrating materials and viewing the universe’s extreme conditions, while visible light is key to our daily visual experience.

Visible light is the spectrum of light that human eyes can detect and interpret, enabling us to see the colours and shapes of the world around us. It plays a crucial role in daily life, from perceiving our environment to the functioning of technologies like cameras and screens. Unlike X-rays, which are used in medical imaging and astronomy, visible light is essential for the biological and psychological aspects of vision, influencing everything from circadian rhythms to mood and perception. Circadian rhythms are our body’s natural 24-hour cycles, mainly controlling our sleep-wake patterns. They affect hormones, temperature, and metabolism, and are influenced by environmental light.

ROLE OF NEUTRON STARS, BLACK HOLES

In the vast expanses of the universe, gas heated to a million degrees is quite common. In places where X-rays are prominent, you often find a neutron star or a black hole orbiting another star. These dense remnants of massive stars that have ended their life cycles exert a strong influence on their surroundings, particularly in attracting gas from nearby stars.

FORMATION OF ACCRETION DISKS

The gas drawn away from these stars forms a disk that encircles the neutron star or black hole. Due to the immense gravitational pull of these dense objects, the gas in the disk accelerates and heats up drastically, emitting bright and intense X-ray light. This phenomenon showcases the incredible gravitational force exerted by neutron stars and black holes.

X-RAY EMISSION FROM GAS COMPRESSION

Rapid compression of interstellar gas results in intense heating, emitting X-rays. A classic example is the shockwave from a supernova, which sends a wave of X-ray emission through space. This process highlights the dynamic and ever-changing nature of the universe.

GALACTIC CLUSTERS, X-RAY PERMEATION

X-rays are also a significant feature of galactic clusters, the largest structures known in the universe. These clusters contain thousands of galaxies held together by gravity, moving in a cosmic dance. X-rays illuminate these clusters, revealing interactions and motions on a grand scale.

GALAXIES: CITIES OF STARS

A galaxy is an immense collection of stars, planets, gas and dust—all bound together by gravity. This cosmic ‘city’ plays a vital role in the structure and evolution of the universe.

GALACTIC COLLISIONS AND CLUSTER DYNAMICS

Within galactic clusters, collisions among member galaxies are common. The energy released in these colossal clashes heats the surrounding gas, contributing to the overall dynamics and evolution of these clusters.

IMPORTANCE OF DARK MATTER

Studying X-ray emissions from galactic clusters provides insights into galaxy evolution and the nature of dark matter. This elusive substance, while invisible, exerts a gravitational force that holds these clusters together, playing a critical role in the structure of the universe.

CHALLENGES OF STUDYING X-RAYS ON EARTH

One major challenge in studying cosmic X-rays is Earth’s atmosphere, which effectively absorbs these rays. This protective layer shields us from the harmful effects of high-energy radiation but necessitates the placement of X-ray telescopes above the atmosphere to study these emissions.

REVEALING THE HIDDEN UNIVERSE

X-ray telescopes have unveiled a hidden, energetic universe. They trace streams of hot gas between stars and galaxies, providing insights into neutron stars, black holes, supernova remnants and galactic collisions. The discovery of extraterrestrial X-ray sources has revolutionized our understanding of the most extreme environments in the cosmos.

X-ray astronomy opens a unique window into the universe’s most energetic and dynamic phenomena. It helps us understand the formation and behavior of celestial bodies, the nature of dark matter and the evolutionary processes of galaxies, offering an unparalleled glimpse into the workings of our universe.

Girish Linganna
Aerospace & Defence Analyst

(The author of this article is a Defence, Aerospace & Political Analyst based in Bengaluru. He is also Director of ADD Engineering Components, India, Pvt. Ltd, a subsidiary of ADD Engineering GmbH, Germany. You can reach out to him at: [email protected])