10 Astronomers and Their Impact

The complexities of Earth and all its oceans, mountain ranges, and natural phenomenon have stunned scientists since the beginning of time. However, there is a group of intelligent researchers that looked beyond what we could see here on Earth and began asking other-worldly questions: Astronomers.


By studying the stars we can see from Earth, the complexities of the solar system, and now, by enabling the deep exploration of space, astronomers have changed our understanding of the universe that lies beyond our world. Every human can connect with the experience of wondering what is out there and what the twinkling lights in the sky really are. But some humans, astronomers, weren’t satisfied with simply pondering the possibilities; they wanted to find out.


Astronomers are often trained in multiple disciplines, have a detailed understanding of topics like physics and motion, and have answered some of the most complex questions the human brain can ask. All astronomers have played a critical role in shaping our understanding of the solar system and beyond, but there are a few key scientists that had an impact greater than what seemed possible for one person. 

Here are 10 astronomers that altered our understanding of reality and their discoveries:

Nicolas Copernicus (1473-1543)

Nicolas Copernicus was a Polish astronomer that challenged the idea of Ptolemy and instead suggested that all planets revolve around the sun, calling his theory the Helio-Centric Theory. His theory pointed out that Earth revolved around the sun one time per year, as well as rotated on its own axis each day. The Earth’s rotation on its own axis is what causes the progression of the seasons we know today, and Nicolas Copernicus was the first to discover this.


Unfortunately for him, Nicolas spent most of his life with his work being rejected by the astronomy community. It wasn’t until nearly 100 years after his death that his theory would be supported by Galileo’s study. The Helio-centric (sun-centric) theory is what is used by all of us today. Our understanding of yearly birthdays, weather patterns, and more all were built on the foundation of Copernicus’s work.

Tycho Brahe (1546 – 1601)

As a Danish nobleman, Tycho received an excellent education and sparked an interest in astronomy. He was one of the last astronomers to be considered a “naked-eye” astronomer, meaning his research wasn’t supported by a telescope. He created his own piece of equipment called the Tychonian Quadrant and used it to measure the coordinates of objects in space. He was able to prove that comets are not part of Earth’s atmosphere and are independent objects floating through space. What Tycho accomplished during his time as an astronomer is especially remarkable considering his limited set of tools to work with.


Eventually, he developed a model of the universe called the Tychonic system which believed correctly that the moon orbited Earth and all other planets orbited the sun. The small error in his model was that he claimed the sun orbited the Earth, which, today we know to be untrue.


He continued his work and correctly mapped over 1,000 fixed stars, building a mathematical foundation used by future astronomers for decades. In 1572, Tycho discovered a supernova and observed it, concluding that stars could change over time. In this period, astronomers believed stars were unchanging, so this discovery sent shockwaves through the field and completely altered the future study of astronomy.

Galileo Galilei (1564-1642)

Often incorrectly labeled as the one who created the optical telescope, Galileo refined the telescope to be much more powerful than it was. At the time, most telescopes could magnify up to 3x, but Galileo, working with those optical telescopes as his foundation, created a telescope that could magnify up to 20x, revolutionizing the study of the universe.


With his exponentially stronger telescope, Galileo was able to discover the four primary moons of Jupiter and the rings of Saturn. Additionally, because his research supported it, Galileo was an outspoken supporter of Copernicus and the Helio-Centric Theory. At the end of his life, the Catholic church forced Galileo to publicly denounce the theory and placed him on house arrest for 9 years until his death. Despite strong criticism and backlash from ruling bodies, this theory became widely accepted because of Galileo.

Edmond Halley (1656-1742)

Potentially the most well-known comet in history, Halley’s Comet, was named after Edmond Halley. Every 75-76 years, this comet would return and be visible from Earth, but most astronomers thought it was a different comet each time. It was Halley that recognized this was the same comet each time and he correctly predicted it would return again in 1758. Unfortunately, he was no longer alive to see his prediction ring true, but the understanding of Halley’s comet changed how astronomers studied comets.


Though Halley’s Comet is the major legacy of Edmond Halley, he also was the first person to observe the transitory patterns of Mercury and concluded that a similar analysis of Venus could provide enough information to measure the size of the solar system. This method provided a viable way to measure the distance between the Earth and the sun, which, at the time, was an amazing feat.

William Herschel (1738 – 1822)

Dedicating much of his life to the rigorous study of the cosmos, William Herschel discovered Uranus and its two moons called Titania and Oberon. He also identified moons on Saturn and found the ice caps on Mars. After studying and documenting 2,500 objects in the sky, he concluded that the nebulae were made of star clusters. It was this theory that created the foundation for the theory of stellar evolution.


You may recognize his name as a brand of telescopes that are still widely known today; Herschel spent nearly every day constructing telescopes that he could use to study the planets and the stars. His telescopes were known for being extremely accurate and had a magnification capacity of more than 6,000 times. Starting in 1774, Herschel kept a detailed journal of his observations and discoveries, leaving a paper trail of all the great work he committed his life to.

Henrietta Swan Leavitt (1868 – 1921)

Henrietta worked at the Harvard College Observatory as a human computer, calculating complex equations in a time when computers did not yet exist. Largely, her calculations were meant to measure the brightness of stars, but she ended up discovering a relationship between a time period and the light of stars called Cepheid variables, which are a type of star that pulse differently and produce changes in brightness.


Her discovery gave astronomers the ability to measure the distance between galaxies; this was especially helpful for those galaxies far away. The cosmic distance ladder was a method that was far more sophisticated than prior methods of measuring distance in space. Before this breakthrough, scientists could measure hundreds of light-years, but this enabled them to measure up to around 20-million light-years.

Edwin Hubble (1899 – 1953)

As a well-known, household name in the field of astronomy, it often surprises people that Hubble studied law and served in the military prior to making a career change later in life to become an astronomist. As an astronomist, one of his most groundbreaking discoveries was that there were galaxies beyond the Milky Way, the galaxy we are part of. He was consistently able to prove that he was seeing stars that were much too far away to be in the Milky Way. He was a trailblazer in studying galaxies beyond ours, and he inspired many future astronomists to do the same.


Colleagues before Hubble were beginning to research and understand the expansion of the universe, but Hubble’s research illustrated how galaxies were moving away from Earth in a consistent proportion to their distance. Simply put, the further away a galaxy is, the faster it is moving away. This idea came to the known as Hubble’s Law and was just one of the many name-sake legacies Edwin left behind.

Vera Rubin (1928 – 2015)

During her study of spiral galaxies, Vera Rubin discovered dark matter. Though we didn’t know anything about its existence until her research, astronomers today believe there is up to 6x more dark matter than visible matter in the universe. In the solar system, known planets such as Saturn and Mars orbit around the sun at different speeds from one another, but as they get closer to the Sun, they all speed up. 


Dr. Rubin discovered that this behavior was not the same in spiral galaxies; stars at the edge of the galaxies moved more quickly than expected, proving that something was different. The discovery of dark matter brought on further investigation and led to the discovery of dark energy. It is thought that dark matter and dark energy make up 95% of the universe, and there is still so much we still don’t know.

Stephen Hawking (1942 – 2018)

One of the most brilliant scientific minds of current times, Stephen Hawking had multiple groundbreaking discoveries and theories, but perhaps one of the most important aspects of his legacy is how much he sought to educate the general public. He took incredibly complex information and made it digestible, hoping to give people an idea of what is going on in the universe.


The most powerful claim he made was that just as the universe had a beginning with the Big Bang, it would also have an end. His research also showed that the universe has no boundary or border; it is infinite. Hawking did this astounding work while battling Amyotrophic Lateral Sclerosis, a motor neuron syndrome that he began experiencing at age 20. In 2018, Stephen Hawking passed away, but he lives on through the research he left behind and the people he left inspired.

Nancy Grace Roman (1925 - 2018)

As the first Chief Astronomer for NASA, astronomer Nancy Roman fearlessly pioneered the exploration of sending telescopes to space. By being able to send telescopes to space, the blurry images and distortion from Earth’s atmosphere are eliminated, providing clearer pictures and more insight as to what is happening in space.


The Hubble Telescope, named after Edwin Hubble, was launched into space in 1990 provided data and images for over 30 years. Over 18,000 scientific papers from the last three decades reference findings from the Hubble Telescope. This breakthrough in how we analyze space would likely not have happened without Nancy’s research and leadership through it all. To honor her, NASA will launch another telescope into space, and it will be named after Nancy.

Discoveries That Lead to More Questions

With astronomy and space exploration, it seems that when one question gets answered, a million more get created. It is through the work of incredible scholars that the chain of discovery stays alive. If the astronomer Galileo hadn’t continued on the path that Copernicus had set, who knows where we would be today. Space is so complex that each lifetime of astronomers can only understand little bits and pieces of it, then do their best to pass that understanding to the next generation of astronomers.


Every astronomer, no matter how “big” or “small” their discovery is, is a crucial part of understanding what lies beyond our own atmosphere. There was a time when we never could have conceptualized the idea of life on any other planet, and just a few centuries later, we have a better grasp on what is out there. Our study of space will never be complete; there are so many nuances and complexities that the more we learn the more we realize we have only learned a small piece of the puzzle.

Check out other articles from our blog for more astronomy and star facts.