EXPLORATION
EXPLORE
The Infamous Hubble Space Telescope
- Published On
November 14th, 2024
- Author
Muhammad Hamzah
Introduction
Since the earliest days of human existence, lone watchers have stood beneath a sky ablaze with stars, transfixed by their silent allure. To those ancient stargazers, the heavens were more than just a canvas of scattered lights, they were a ream of mystery; a wellspring of wonder that whispered of the divine. The firmament guided explorers across unknown lands and seas, marked time for planting and harvest, and sparked myths that explained the universe and humanity’s place within it.
Then came astronomers like Copernicus, revolutionizing our understanding of the universe. By placing the Sun—not Earth—at the center, he broke open our view of the cosmos. Galileo’s telescope and Kepler’s precise laws drove this shift forward, opening an era where observation and mathematics revealed a universe more complex and vast than primeval minds could fathom. These early breakthroughs laid the foundation for the technological leaps that followed, culminating in modern tools like space telescopes, interplanetary probes, and advanced computational models. Today, we no longer rely solely on the naked eye; cutting-edge technology enables us to peer deeper into the cosmos than ever before, uncovering the universe’s most profound mysteries, with one of the most important tools being the Hubble Space Telescope.
In 1990, we reached a turning point in this age-old quest. The launch of the Hubble Space Telescope on April 24, 1990, marked a leap in our understanding. As one of the largest and most versatile telescopes ever sent into space, it took us beyond Earth’s atmosphere, away from clouds, light pollution, and atmospheric distortion, placing a lens into the cosmos. With it, we gained an unprecedented view of the universe and uncovered insights that would redefine our knowledge. The Hubble Space Telescope allowed us to observe distant galaxies, witness the birth of stars, and peer into the farthest reaches of space, leading to breakthroughs like the confirmation of the expansion of the universe. But Hubble’s journey, like all great endeavors, had a beginning—and in this case, that beginning came from the pioneering work of Edwin Hubble.
Edwin Hubble
Edwin Hubble, the pioneering astronomer, is seen seated at the 100-inch Hooker reflecting telescope—one of the largest of its time—at the Mount Wilson Observatory in California. (Photo Credit: Getty Images)
Hubble was born in 1889 in Marshfield, Missouri, at a time when astronomy was still grappling with age-old concepts of a static and finite universe. Though he began his career as a lawyer, Hubble’s heart was set on the stars, and he soon returned to his true calling—astronomy. Hubble’s early life showed an inclination toward excellence, earning him a scholarship to the University of Chicago in 1906. He later became a Rhodes Scholar and studied at the University of Oxford. However, it was not until after World War I that the young graduate joined the Mount Wilson Observatory in California. At the time, many astronomers believed the Milky Way to be the entire universe, a belief grounded in centuries of limited observations. It was there, in 1923, using the then-mighty Hooker Telescope, that Hubble identified Cepheid variable stars in the Andromeda Nebula. This discovery revealed that entire galaxies, each containing billions of stars, were scattered far beyond the Milky Way.
But Edwin Hubble’s work didn’t stop there. In addition to his groundbreaking discovery of galaxies beyond the Milky Way, Hubble made another pivotal observation: he noticed a peculiar trend where these galaxies appeared to be moving away from each other in a consistent pattern. This relationship between the distance of a galaxy and its redshift—a measure of how much its light is stretched—became known as Hubble’s Law. Hubble’s observation suggested that the universe was expanding, a revolutionary idea at the time. Despite facing some opposition and skepticism from certain members of the scientific community, Hubble’s findings were crucial in supporting the notion of an expanding universe. This concept was later formalized by physicists such as Albert Einstein, who adjusted his general theory of relativity to account for the expanding cosmos, and Alexander Friedmann, whose equations predicted such an expansion. Hubble’s work not only transformed our understanding of the universe, but also laid the foundation for future astronomical discoveries. This legacy of pushing challenging boundaries and expanding scientific horizons is what inspired NASA to name their ambitious space telescope after Hubble.
Initial Obstacles
Atmospheric distortion has been a challenge for astronomers for centuries. For example, Galileo Galilei struggled to clearly observe the rings of Saturn in the early 17th century due to atmospheric interference. Similarly, Sir William Herschel, best known for discovering the planet Uranus in 1781, faced difficulties in observing distant nebulae because of the blurring effects of the Earth's atmosphere. This persistent problem needed a solution, which was eventually proposed in the 1940s by American astrophysicist Lyman Spitzer. Spitzer suggested that placing a telescope above Earth's atmosphere would eliminate these distortions, enabling more accurate and detailed observations of deep-sky objects. But it would be decades before this idea became a reality. By the 1970s, NASA and the European Space Agency (ESA) were collaborating on a project they called the Large Space Telescope (LST), a venture that would bring together the best of international resources and expertise. The vision was grand, but the path was strewn with hurdles.
Pictured here is the explosion of the Challenger Space Shuttle, a tragic event that occurred on January 28, 1986, just 73 seconds after liftoff. The disaster claimed the lives of all seven crew members, including a civilian schoolteacher, Christa McAuliffe, who was set to be the first teacher in space. (Photo Credit: NASA Archive)
Funding was an ongoing battle. Budgets shifted, political support waxed and waned, and setbacks abounded but eventually Congress granted funding for NASA's portion of the Large Space Telescope (later named Hubble to honor Edward Hubble) in 1977. However, delays pushed back the date of launch further and further with the most heartbreaking of these being the Challenger disaster in 1986, which put the space program on hold and cast doubt on Hubble’s future. Yet despite the obstacles, scientists and engineers pressed on, driven by the dream of viewing the universe as it had never been seen before. Finally, on April 24, 1990, the space shuttle Discovery launched the $1.5 billion Hubble Space Telescope into low orbit.
But the excitement was short-lived. Hubble’s images were blurry, a shocking setback caused by a tiny flaw in the primary 2.4-meter-wide mirror—just 2.2 micrometers, thinner than a human hair. It was a humbling blow for NASA and an enormous disappointment for the scientific community. However, this challenge only spurred them on. In December 1993, astronauts aboard the space shuttle Endeavour undertook a daring repair mission, installing corrective optics to fix the mirror's flaw, along with a Wide-Field Planetary Camera that would later capture some of the most iconic photos Hubble ever took. This repair transformed Hubble, turning it from a costly disappointment into one of the most successful scientific instruments of all time. The first images sent back afterward were out of this world—literally.
Design and Instruments
A cutaway diagram of the Hubble Space Telescope provides a detailed look at the internal structure and components of this groundbreaking observatory. It highlights key systems such as the Optical Telescope Assembly (OTA), which houses the primary and secondary mirrors, as well as the various scientific instruments like the Wide Field Camera, the Advanced Camera for Surveys, and the Space Telescope Imaging Spectrograph. (Photo Credit: NASA Science)
The Hubble Space Telescope (HST) is a remarkable feat of engineering, a testament to humanity’s pursuit of knowledge and precision in the realm of astronomy. Launched in 1990, it was designed to overcome the limitations of ground-based telescopes, which are hindered by Earth's atmosphere. In the vacuum of space, Hubble has been able to capture light across the electromagnetic spectrum, producing some of the most detailed and profound images of the universe ever seen. At the core of the Hubble’s optical system is its 2.4-meter primary mirror, made of 18 hexagonal segments of ultra-lightweight glass coated with a thin layer of aluminum. This primary mirror is responsible for gathering light from distant celestial objects, and reflects it toward a secondary mirror, positioned at the telescope’s focus. The secondary mirror redirects this light toward Hubble’s suite of scientific instruments, where it is analyzed to reveal the distant universe in unprecedented detail.
One of the most groundbreaking aspects of the Hubble Space Telescope was its suite of scientific instruments, specifically designed to capture high-resolution images and data across multiple wavelengths of light. Initially, the telescope was equipped with instruments such as the Wide Field and Planetary Camera (WFPC) and the Faint Object Camera (FOC). The WFPC provided detailed images of planets within our solar system, while the FOC was designed to capture images of faint, distant objects—often objects millions, or even billions, of light-years away. These instruments marked a significant leap in observational capability, allowing Hubble to peer deeper into the universe than ever before. However, the telescope’s true potential was not fully realized until several upgrades were implemented during servicing missions. The first major upgrade occurred in 1993, when a corrective optics device was installed to compensate for a flaw in the primary mirror, a flaw that had been discovered shortly after launch. This device, known as the Corrective Optics Space Telescope Axial Replacement (COSTAR), enabled Hubble to achieve sharp, high-resolution images as originally intended.
Astronaut Jeffrey Hoffman carefully removes the Wide Field and Planetary Camera 1 (WFPC 1) during the first Hubble servicing mission, STS-61, in December 1993. This operation replaced WFPC 1 with the upgraded WFPC 2 to correct Hubble's optical issues (Photo Credit: HubbleSite)
One of the most significant upgrades came in 2002 with the installation of the Advanced Camera for Surveys (ACS), which expanded Hubble's observational capabilities by improving the telescope’s ability to capture deep-field images. The ACS, equipped with three distinct channels to observe ultraviolet, visible, and near-infrared light, allowed Hubble to examine some of the most distant and faint objects in the universe, revealing phenomena like the formation of galaxies and stars in the early universe. The ACS was a major step forward, allowing Hubble to capture more detailed images, such as the famous Hubble Ultra Deep Field, which revealed thousands of galaxies that were formed billions of years ago. In 2009, Hubble’s capabilities were further enhanced with the addition of the Wide Field Camera 3 (WFC3), which expanded its range across the electromagnetic spectrum to include ultraviolet and near-infrared wavelengths. This upgrade allowed the telescope to observe objects in new ways, from uncovering the formation of galaxies to studying the atmospheres of exoplanets. The WFC3 was also instrumental in studying distant quasars and supermassive black holes, helping to refine our understanding of the evolution of galaxies.
Hubble’s orbital dynamics are crucial to its ability to gather sharp images. It orbits Earth at an altitude of approximately 547 kilometers, completing one revolution every 95 minutes at a velocity of 28,000 kilometers per hour (17,500 miles per hour). This rapid orbit, combined with Hubble’s lack of atmospheric interference, allows it to collect detailed data from regions of space that would otherwise be obscured. Despite these speeds, Hubble maintains exceptional stability, thanks to a combination of gyroscopes and fine guidance sensors. These instruments allow the telescope to stay locked on a target with extraordinary precision—like aiming a laser at a coin 200 miles away—ensuring that images captured are crisp and clear.
The Hubble Space Telescope orbits Earth at 570 kilometers, enabling servicing missions, while the James Webb Space Telescope (JWST) is located 1.5 million kilometers away at the second Lagrange point (L2), offering infrared observations free from Earth's atmosphere. (Photo Credit: NASA Science)
Hubble’s power comes from its two large solar arrays, which generate approximately 2,800 watts of electricity, enough to keep the telescope operational. These solar arrays convert sunlight into electrical power, which is stored in batteries for use when Hubble is in the Earth’s shadow. The telescope’s longevity has been ensured by a series of servicing missions, carried out by NASA’s Space Shuttle program, which has replaced and upgraded instruments, repaired components, and maintained the telescope’s systems. The total cost of the Hubble Space Telescope, including its development, launch, and operational costs, is estimated to be over $10 billion. Despite early setbacks, such as the mirror flaw, Hubble has consistently delivered remarkable scientific results and continues to be one of the most productive telescopes in history. Its ability to observe distant stars, galaxies, and nebulae has provided invaluable insights into the nature of the universe, the formation of cosmic structures, and the origins of stars and planets. Hubble's legacy, defined by its technological innovation and the groundbreaking discoveries it has enabled, continues to shape our understanding of the cosmos.
Discoveries
Once its optics were corrected, Hubble began sending back images that captivated the world and revolutionized science. Like a time machine, the telescope captured distant objects as they appeared in the past, revealing their light as it had traveled millions or even billions of years to reach Earth. This allowed astronomers to observe phenomena that were previously unreachable, such as the formation of stars, the behavior of galaxies, and the age of the universe itself. Its discoveries were nothing short of revolutionary. Perhaps its most iconic image, the “Pillars of Creation,” captured towering clouds of gas and dust within the Eagle Nebula, where stars are actively being born. Hubble showed us not just static snapshots of the universe but the processes of creation and destruction that define it. However, The process by which the Hubble Space Telescope (HST) captures its renowned images, like the “Pillars of Creation,” is intricate and detailed, representing a sophisticated blend of technology, data analysis, and scientific insight. Each image we see is the final product of a meticulous sequence that begins with precise data collection in space and culminates in multi-layered visual representations that reveal otherwise invisible phenomena in the cosmos.
The process starts with Hubble's targeting of a specific region in space. This involves its pointing and stabilization systems, which lock onto a target with astonishing accuracy. Hubble’s stability is critical, especially for images that require long exposure times to capture faint, distant objects. Once stabilized, Hubble’s instruments can begin to collect data, recording the light from the chosen region across a range of wavelengths using various filters. For an image like the "Pillars of Creation," Hubble gathers light across the ultraviolet, visible, and near-infrared spectra. Each filter isolates specific wavelengths, allowing astronomers to gather multiple "slices" of information about the object. Each wavelength can reveal a unique feature: ultraviolet light might highlight young, energetic stars, while near-infrared can pierce through dust to expose structures hidden from view in visible light.
These majestic Pillars of Creation, composed of cosmic dust and gas, are located at the heart of M16, or the Eagle Nebula, about 6,500 light-years from Earth. Spanning over 4,000 light-years, they are a vibrant stellar nursery where new stars are born from dense clouds of gas and dust. (Photo Credit: HubbleSite)
Data that Hubble transmits back to Earth is digital and consists of individual exposure frames. Each frame corresponds to light intensity measured through one specific filter at one wavelength. These exposures are not initially visual images; they are grayscale readings that quantify light intensity at each pixel, effectively representing the brightness and distribution of the light in the observed area. Because the raw data contains distortions due to the telescope's movement, thermal fluctuations, and sensor-specific characteristics, the initial step in processing involves calibration to correct for these effects. This includes adjusting for any cosmic ray interference, sensor noise, and inconsistencies in Hubble’s positioning over long exposure times. Once calibrated, these individual frames from multiple filters are aligned and combined into a composite image. This process, known as stacking, corrects for slight shifts and rotations in each frame to ensure that each filter's data aligns perfectly. For an object like the Eagle Nebula, where features appear in different wavelengths, the stacking process is critical to build a clear, cohesive image that accurately represents the region. The combined composite captures a fuller range of details, layering the contributions from each filter to reveal the different physical components in a single image.
A significant part of Hubble’s data-processing pipeline is the application of color, transforming the stacked grayscale data into the vibrant, detailed images familiar to the public. This process is known as "color mapping." Since the data from Hubble is primarily in grayscale, colors are added to represent different wavelengths of light captured by each filter. These colors are not arbitrary; they are carefully chosen based on the scientific properties of the light in each wavelength. For example, shorter wavelengths, like ultraviolet, might be mapped to blue, while longer wavelengths, like near-infrared, might be assigned a red hue. In the "Pillars of Creation," colors are applied in a way that not only creates a striking visual contrast but also highlights the gas clouds and young stars in scientifically meaningful ways, effectively allowing astronomers to "see" physical characteristics like temperature, density, and ionization levels.
A significant part of Hubble’s data-processing pipeline is the application of color, transforming the stacked grayscale data into the vibrant, detailed images familiar to the public. This process is known as "color mapping." Since the data from Hubble is primarily in grayscale, colors are added to represent different wavelengths of light captured by each filter. These colors are not arbitrary; they are carefully chosen based on the scientific properties of the light in each wavelength. For example, shorter wavelengths, like ultraviolet, might be mapped to blue, while longer wavelengths, like near-infrared, might be assigned a red hue. In the "Pillars of Creation," colors are applied in a way that not only creates a striking visual contrast but also highlights the gas clouds and young stars in scientifically meaningful ways, effectively allowing astronomers to "see" physical characteristics like temperature, density, and ionization levels.
This image compares the same region of the sky captured by the Hubble Space Telescope's Advanced Camera for Surveys (right) and the Subaru 8-meter telescope's Supreme Camera. Both are color composites created by combining images taken through blue, visible, and infrared filters, revealing the region within the GOODS North field. (Photo Credit: NASA)
The colors are thus both representative and interpretative: they visualize information about the chemical composition and physical conditions within the nebula. In the case of the Eagle Nebula, the blue regions often indicate the presence of ionized oxygen, while red and yellow hues reveal areas rich in hydrogen and sulfur. These colors guide astronomers by marking out the boundaries of the dust clouds and the regions where stars are actively forming. While the colorized images are stunning, their purpose is not simply aesthetic. They serve as scientific diagrams, encoding essential data about the cosmic scene. The finished images are therefore the result of extensive processing, where astronomers and imaging specialists translate raw data into a form that conveys both the beauty and the scientific complexity of the cosmos. Each detail—each layer and color—tells a part of the story, showing us regions where stars are born, where they interact with their environment, and where they eventually die, releasing their materials back into space. Through this painstaking process, the Hubble Space Telescope offers us a view not only of the stars but also of the fundamental processes that govern their life cycles and the evolving fabric of space itself.
One of Hubble’s most groundbreaking contributions has been its role in measuring the rate of the universe’s expansion. In 1998, two independent research teams—the High-z Supernova Search Team and the Supernova Cosmology Project—used the Hubble Space Telescope to observe distant Type Ia supernovae, exploding stars that serve as reliable distance markers. They expected to find that the universe’s expansion was slowing due to gravity, but instead discovered it was accelerating, suggesting a previously unknown force, now termed dark energy, was the catalyst behind this expansion. Observations from Hubble, made possible by its ability to detect faint light from billions of light-years away, were critical in this revelation, setting the stage for a new era of research into the nature of the cosmos.
Another of Hubble’s groundbreaking achievements was the Hubble Deep Field, an image captured in 1995 of a seemingly empty region of the sky in the constellation Ursa Major. For 10 consecutive days, Hubble focused its gaze on this dark patch, revealing more than 3,000 previously unknown galaxies, some of which were over 13 billion years old. This image provided a glimpse into the distant past, showcasing galaxies that formed shortly after the Big Bang. Building on this success, Hubble conducted even deeper observations of the same area, leading to the Hubble Ultra-Deep Field in 2004. This image captured even more distant galaxies, extending our view of the universe’s early stages. Then, in 2012, the Hubble eXtreme Deep Field was released, pushing the boundaries of astronomical discovery further, uncovering some of the most ancient galaxies ever observed and significantly deepening our understanding of the universe's evolution. These images have been instrumental in shaping modern cosmology, offering insights into the formation and development of galaxies in the early universe.
This image, known as the Hubble Ultra Deep Field, reveals 28 of over 500 young galaxies from less than 1 billion years after the Big Bang, offering a glimpse into the early universe's formation. It provides a profound look at galaxies in their infancy, helping scientists study the origins of galaxy evolution and cosmic history. (Photo Credit: NASA, ESA)
Conclusion
Although our instruments have advanced from basic star charts to orbiting telescopes, the fire within our souls to seek the great beyond has only intensified, flaring rather than fading with each passing century. Each new generation of humankind has been born with a renewed fervor for the heavens above; a deepening longing to unravel the mysteries that stretch beyond our feeble reach. Hubble embodies this ageless spirit—a telescope born of our shared desire to make sense of the obscure, a machine with a heart of polished glass and silicon that gazes out into the vast unknown on our behalf.
We have moved from pondering over what lies across the churning seas to mapping galaxies billions of light-years away, yet the impulse is the same: a child’s wide-eyed wonder, a philosopher’s boundless curiosity, a scientist’s dogged pursuit of truth. The Hubble Space Telescope is proof that we haven’t stopped dreaming—we’ve just found better ways to chase those dreams. All it takes is looking up from the dirt once in a while. As Oscar Wilde puts it:
“We are all in the gutter, but some of us are looking at the stars.”
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