Buzz
Beyond the telescope, the camera stands as one of the most groundbreaking inventions in astronomy. With its advent, astronomers could go beyond rough sketches in notebooks, taking weeks to analyze a single photo and uncover its intricate details.
Astronomers have since captured some of the universe’s most awe-inspiring objects and phenomena through their lenses, and certain images have cemented themselves as legendary milestones in the history of astronomy.
10. The Formation of a New Solar System
In the past, the formation of planets was understood only through mathematical models and simulations. However, in 2014, astronomers managed to capture the process with unprecedented clarity.
The image displays a protoplanetary disk surrounding a young star, HL Tauri, after the star’s residual material has settled. You can spot distinct rings within the disk, which represent the orbits of planets in the making.
What’s the most incredible part?
This system is actively forming planets, and HL Tauri is only about one million years old! This photograph led astronomers to conclude that planet formation begins almost immediately after a star’s birth.
9. Supernova 1987A
When the most massive stars in the universe reach the end of their lives, they explode. This explosive event is called a supernova, and its light can travel across millions or even billions of light-years. Before 1987, all we could observe were supernovae from these vast distances, leaving us with limited knowledge.
Then, on a cold winter evening in 1987, observers witnessed the light of a blue supergiant that had gone supernova in the Large Magellanic Cloud, a satellite galaxy of the Milky Way, located just 166,000 light-years away. This explosion, known as SN 1987A, was the closest supernova to Earth since Kepler’s Supernova in 1604. It presented a unique chance to closely examine the death of a star.
Much of our current understanding of supernovae stems from SN 1987A. Astronomers discovered the entire sequence of events leading up to such an explosion, gained undeniable evidence that these events produce the elements essential for life on Earth, and even detected the elusive neutrinos (particles similar to electrons) created in the blast.
8. Cracks In Europa
On July 9, 1979, NASA’s Voyager 2 spacecraft made a flyby of Jupiter and provided the first high-resolution images of Europa, one of the planet's moons. Scientists, aware of Europa's low density, already suspected it contained a large amount of water. However, its great distance from the Sun (5.2 times farther than Earth) led many to believe that all of Europa's water was frozen.
The scientific community was shaken when Voyager 2 transmitted a photo showing Europa’s surface covered with numerous dark streaks. A topographic map revealed these streaks to be enormous cracks in the icy crust.
These features resemble those seen in Earth’s ice sheets, where a liquid ocean beneath the ice causes it to crack, allowing water to flow between the fissures and freeze over. Scientists now theorize that beneath Europa's surface lies an ocean of liquid water, possibly several miles deep. What could be living there?
7. Stars Orbiting A Supermassive Black Hole
Sagittarius A* is an enigmatic radio source located at the heart of our Milky Way. It has long been theorized that Sagittarius A* is a unique type of black hole—a supermassive one.
Black holes are typically thought of as remnants of massive stars that have exploded in supernovae. These black holes generally weigh about as much as 10 Suns. However, supermassive black holes are vastly larger, often having masses millions, or even billions, of times greater than that of the Sun.
In 2002, the existence of supermassive black holes was largely confirmed when a team of international astronomers captured an extraordinary photograph of a star orbiting Sagittarius A*. The image is haunting; the star appears to orbit a void, yet it's traveling at an incredible 5,000 kilometers (3,100 miles) per second.
By mapping the star's orbit, scientists were able to probe the gravitational field of Sagittarius A*, providing almost definitive proof that it must be a supermassive black hole. This photograph also offers strong evidence that the dense concentrations of mass observed at the centers of other galaxies are similarly supermassive black holes.
6. The Hubble Deep Field
The Hubble Space Telescope is one of the busiest telescopes on Earth. Therefore, it came as a surprise when, in 1995, scientists decided to aim it at an entirely empty region of space for 10 continuous days. What they discovered was remarkable: the area was far from empty.
The image revealed nearly 3,000 galaxies, many too faint to have been detected before. Every speck of light in the image represents a galaxy, some so distant that we’re seeing them as they were 10 billion years ago, witnessing the early stages of their formation.
Additionally, the image features galaxies much closer to us, creating a kind of cosmic timeline. Named the Hubble Deep Field, this photo captures a tiny fraction of the sky (roughly 1/30th the size of the full Moon). The incredible number of galaxies within such a small patch underscores the immense scale of our universe.
5. The Bullet Cluster
When astronomers observe a galaxy, they often find its gravitational pull to be much stronger than what the stars and gas inside the galaxy can explain. This puzzle is one of the biggest unresolved issues in astrophysics, but dark matter might be the key to understanding it.
Dark matter is a theoretical particle that doesn’t interact with light in any way, but many believe it makes up most of the universe's mass. Although its existence is still debated, a famous image from 2006 provides powerful support for this concept.
The image, known as the Bullet Cluster, shows two galaxy clusters colliding. The collision created a rare phenomenon where the stars have been separated from the surrounding gas and dust.
Although gas and dust make up the bulk of a galaxy's mass, they don't seem to have the greatest gravitational influence. Instead, gravity is concentrated around the stars, suggesting that there might be an unseen force exerting a heavy pull in the universe.
4. An Actual Photograph of a Black Hole
While capturing an image of a black hole may seem impossible due to its nature of emitting no light, the matter falling into it does produce light. According to Einstein’s general theory of relativity, a black hole will cast a 'shadow' or 'silhouette' within the surrounding glowing gas, which can indeed be photographed.
Since this target is extremely faint, the process theoretically requires a telescope as large as Earth itself. Remarkably, this is exactly what the scientists from the Event Horizon Telescope accomplished.
By connecting eight telescopes from around the world, they created a virtual telescope with a diameter equivalent to the distance separating them. After extensive data analysis, the resulting image instantly became a landmark achievement in history.
This image reveals a supermassive black hole, 6.5 billion times heavier than the Sun, residing at the center of the M87 galaxy, located 55 million light-years from Earth. The event horizon, or the boundary of the black hole, appeared precisely as Einstein’s theory had predicted, offering unprecedented confirmation of his theory.
3. The Solar Eclipse of 1919
Is it possible for gravity to bend light?
It’s a bold concept, yet a young Albert Einstein had complete conviction in it. Einstein’s theory of general relativity didn’t merely spark a revolution in astronomy—it fundamentally reshaped the entire landscape of physics. While Newton could explain the effects of gravity, Einstein essentially provided an answer to the profound question: 'Why does gravity occur?'
According to Einstein’s concept, space behaves like a stretched trampoline. When a massive object, like the Sun, rests upon it, space becomes distorted. This curvature of space then causes objects, such as the Earth, to orbit naturally, as they simply follow the path dictated by the curvature.
Though the theory sounds astonishing, the scientific community required proof. Einstein proposed that if one could demonstrate how the Sun’s gravity bends the light from distant stars behind it, his theory would be validated. However, such a test could only be conducted during a solar eclipse, as the Sun’s intense brightness would otherwise obscure the stars.
In May 1919, three years after Einstein introduced his general relativity theory, a total solar eclipse occurred. Following Einstein’s instructions, renowned astronomer Arthur Eddington captured a photograph of the eclipse, marking the position of the stars behind it.
However, the stars weren’t positioned as expected, signaling that their light had indeed been bent. Overnight, Einstein became an international sensation, and the photograph became an iconic piece of history.
2. The VAR! Plate
Before 1923, there was uncertainty about whether the Milky Way was the entire universe or if other galaxies existed. Although astronomers had spotted other galaxies, they appeared only as unclear 'fuzzy' patches, which were initially thought to be nebulae.
One of these objects was the Andromeda galaxy. In October 1923, the renowned astronomer Edwin Hubble turned the world’s largest telescope at the time towards Andromeda. He captured a photograph of the galaxy on a glass plate, which was the standard method for taking astronomical images back then.
Upon detailed examination, Hubble observed that one star’s brightness had shifted compared to previous observations. These are known as variable stars, and this particular type is essential for measuring distance. Thrilled by this discovery, Hubble wrote 'VAR!' (signifying 'variable') on the plate.
By calculating the distance to Andromeda, he discovered that it lies far beyond the boundaries of the Milky Way. Just like that, the universe expanded dramatically. Today, we estimate that the observable universe contains around 100 billion galaxies.
1. The Cosmic Microwave Background
Only 380,000 years after the big bang, the temperature and density of the universe had decreased enough for the first photons (light particles) to travel freely through space. As the universe expanded, these photons were stretched to longer wavelengths. Today, we observe them as microwaves, and we refer to them as the Cosmic Microwave Background (CMB).
The CMB was first discovered in 1965. However, it wasn’t until 1989 that a satellite was launched to take precise measurements and create a panoramic map of the CMB. While more detailed maps were made in subsequent years, it was the initial map that captured the world’s imagination. Not only did it show the imprint of the big bang, but it also provided formal confirmation of the big bang theory.
