A Constellation of Sciences
by Sam Atkins
NOTE: Tap or hover over images for captions and credits.
Image credit: Daniele Pugliesi
Much of astronomy is thought of as simply looking up and marveling at all the twinkles and swirls across the night sky. For sure, this can fill a person with wonder, peace and sometimes even excitement. One can learn a great deal about the solar system and the universe just by looking at it. However, there is so much more to astronomy than this. Astronomy is a deeply interconnected constellation that weaves together insights from many other scientific fields. To truly understand the vastness and complexity of the cosmos, astronomers draw on knowledge from mathematics, physics, chemistry, geology, environmental science, biology, computer science and even psychology. Let’s take a closer look at how the study of space creates a synergy between these different disciplines.
Mathematics
The Language of the Universe
Image credit: Fir0002 / Wikimedia Commons
When you look through the published research papers of astronomers, you are met with marching battalions of numbers, variables, functions and graphs. For many, it is indecipherable as if they are speaking an ancient tongue from a forgotten time. This is not far from reality. If you want to understand the universe; if you truly want to commune with it, you need to speak the language that the universe is speaking. As we learn more about the chaotic cosmos, we find that there is a method to the madness. What may seem like detached randomness is actually the deep complexity of interconnected things and systems all governed by a shared set of quantifiable rules.
Astronomers make sense of all these complexities and rules through the language of math. If you wish to become a professional astronomer yourself, you must learn how to use calculus to model the motion and behaviors of planets or determine the mass of galaxies. You must use algebra to process digital images from space telescopes and map how gravitational lensing bends light around massive objects. You must use trigonometry to calculate stellar distances and chart the positions of objects on the celestial sphere. You must apply the principles of statistics to assess the confidence of measurements and study patterns in large celestial populations.
Physics
How the Heavens Move
Diagram showing various elements of an orbital system. Image credit: Brandir / Wikimedia Commons
One of the most fundamental elements of modern astronomy is our understanding of physics. Everything you see, from the ground beneath your feet to the pinpoints of distant lights in the night sky are governed by the physical laws of the universe. Motion, gravity, electromagnetism, thermodynamics, energy and matter all form the backbone of how we explore and interpret the cosmos.
For centuries, humans have been coming to a more intricate and complete understanding of these laws to unlock the universe’s deepest secrets. Even today, astrophysicists apply Newton’s centuries-old laws of motion and universal gravitation to calculate the orbits of planets and moons, the formation of planetary rings and plot the trajectories of rockets and space probes. This allows us to predict eclipses and rogue asteroids and plan missions into deep space. By analyzing the light from distant stars and planets via spectroscopy, astrophysicists determine their compositions, temperatures, and even velocity and direction of movement. Astrophysicists can explain how energy is generated inside stars via nuclear fusion and transported via radiation and convection. This gives us insight into stellar lifecycles, element formation and allows us to forecast solar activity that affects Earth.
In more complex fields, astrophysicists deal with the profound principles of Einstein’s general relativity and Planck’s quantum theory to probe the universe’s most extreme objects and exotic environments. These include the warped spacetime around black holes, high-energy cosmic rays that streak through the galaxy at near-light speeds, and time dilation, where time seems to slow down in the presence of intense gravity or speed. Cosmologists take a broader view. They investigate the origin, structure, evolution, and eventual fate of the entire universe. By studying distant galaxies, the cosmic background radiation, and the distribution of matter across cosmic time, cosmologists construct models of the universe that trace its expansion from the Big Bang to its possible end.
Meanwhile, theoretical physicists operate at the boundaries between what we know and what we don’t. They use not only their deep knowledge of physics but employ a vivid imagination to think outside the box and grapple with the fundamental nature of reality. Some study string theory, which posits that all particles are tiny vibrating strings within up to eleven dimensions. Others seek to uncover the mysteries of dark matter and dark energy, invisible forces that pervade the universe and enact great force on it through unknown mechanisms.
Chemistry
The Ingredients of Matter
Diagram showing how radiation from Jupiter breaks down molecules that escape from Europa’s subsurface ocean. Image credit: NASA / JPL-Caltech / Wikimedia Commons
With so much of the cosmos far out of reach from human hands, you’d think we’d know almost nothing about it. On the contrary, we know tons! There’s so much that stars and planets communicate to us about themselves simply through their light. Astronomers are able to use spectroscopy to observe and analyze light from objects across vast cosmic distances and learn a variety of different things about them. One of the most surprising things that this reveals is what those far away objects are made of.
Light is made up of different wavelengths (for visible light we see these as colors). When light makes contact with matter, some of those wavelengths are absorbed by or transmitted through the object while some is reflected. Which of these that happens depends largely on the matter’s chemical composition. Objects made of hydrogen will reflect and absorb certain combinations of wavelengths while objects made of carbon will reflect and absorb a different combination wavelengths. When that reflected light reaches us, we are able to pass the light through spectrometers which breaks the light down into its component colors. When we do this, we can see which colors remain (emission lines) and which are missing (absorption lines). This can tell us what that object is made of!
Through analyzing the light spectra, we determine that a gas giant orbiting a star hundreds of light years away contains water vapor in its atmosphere. This is the case in our own solar system, where chemical signatures of expelled salt water have been found gushing from geysers on moons like Europa and Enceladus. This became the catalyst for a space mission that has a space probe currently on its way to Jupiter to investigate whether Europa has a subsurface ocean and/or supports life (you can learn more about this mission here). The discovery of certain complex carbon compounds on another world can also be a strong indicator for the potential for life and give us cause to investigate further.
Imagine how much more we can learn by bringing home samples from these distant worlds to study directly!
Geology
Stories Written In Stone
Outcrops captured by the Perseverance Mars Rover in 2022 show distinct geological strata of sedimentary rock. Image credit: NASA
At first glance, Mars seems to be a quiet, barren and lifeless desert with nothing to say. That last part couldn’t be further from the truth. Mars won’t stop talking to us. When astronomers study the surface features, impact craters, tectonic activity and mineral compositions of other worlds (or even our own), they are able to reconstruct its history. In the case of the red planet, we constantly come across passages about its past written in the numerous riverbeds and deltas that populate its surface. The ancient Martian landscape was almost certainly covered in (probably) liquid water. From space, we can see how rivers are carved through plains, deltas empty into large craters. Closer examination of sedimentary rocks by Mars rovers shows signs of water erosion. Could our solar system have hosted two Earths? If so, did Mars also have life?
On our home planet, the many layers of rock beneath our feet organize Earth’s history into chapters and reveal a world ever-changing. One of the greatest stories told here is the extinction of the dinosaurs. A layer of clay known as the K-Pg boundary marks the point at which the abundance of dinosaur fossils found below comes to an abrupt end. Across the world, geological strata tells the same tale. An asteroid slammed into Earth and wiped out 75% of all species on the planet, ultimately paving the way for mammals to lay their claim (you can learn much more about this incredible story here). Speaking of asteroids…
While they occasionally collide with other celestial bodies and cause a great deal of excitement (or terror, depending on your vantage point), the vast majority of an asteroid’s time is spent just floating around the vastness of space. Many of them have been doing this, undisturbed, for billions of years. This fact is what makes these objects some of the oldest storytellers that we can reach. Studying rock samples obtained from asteroids gives us a window into the early solar system. By learning about their mass, density, and mineral makeup, we can infer how solid material clumped together to form planetesimals, which in turn formed planets. Signs of heating on asteroids (from radioactive decay and collisions) can tell us how early solar system bodies were able to handle extreme temperatures or how they underwent core and crust formation in planets. Studying asteroids that contain pockets of hydrated minerals and organic molecules can tell us how they may have delivered water and the building blocks for life to Earth.
Environmental Science
Monitoring Earth’s Vitals
Hurricane Florence captured from the International Space Station in 2018. Image credit: NASA Goddard Space Flight Center
While astronomers have many space telescopes looking out into the depths of the cosmic ocean, we also have many satellites looking down at our own planet. These are sponsored by numerous government and commercial entities but the U.S. leads in Earth observation capabilities through agencies like NASA and NOAA. Satellites such as Terra, Aqua and Aura (all three make up the Earth Observing System) are equipped with things like infrared imaging and spectroscopic instruments, technology originally developed for space observation. Here, they are used to monitor global temperatures, weather patterns, rising sea levels, glacial melt, deforestation, the ozone layer and various types of pollution.
We also deepen our understanding of Earth’s climate through comparison with other planets. For example, Venus has an incredibly thick atmosphere of carbon dioxide which has created a runaway greenhouse effect that scorches the shrouded surface. Meanwhile, the thin but dusty atmosphere of Mars has left the red planet a frigid, barren world where liquid water can no longer be sustained. These two worlds offer a window into the perils of extreme climate change that we can study in order to address problems on Earth.
Another issue that environmentalists and astronomers share a passion for is light pollution. The increasingly bright glare of city and suburban lighting has gradually stolen the beauty of the night sky from much of the human population, relegating views of the Milky Way to special hours-long trips to dark sites. This problem goes beyond humans, however. The heat and brightness of excessive urban lighting can interfere with the perceptions and rhythms that wildlife rely on to survive and flourish. It can disrupt migration patterns, affect circadian rhythms which leads to sleep deprivation and steal away darkness that protects some animals from predators. It can even affect the life cycles of plants which are accustomed to Earth’s day-night cycle.
Lastly, the environmentalism movement owes some of its early momentum to the Apollo missions which provided humanity with our first collective views of our home world. The visage of our blue marble floating freely in the vast darkness both humbled and empowered people around the world. Earth became a precious but fragile thing that needs to be protected.
Biology
The Search for Life Amongst the Stars
The Allen Telescope Array (ATA) is a joint effort by the SETI Institute and the Radio Astronomy Laboratory (RAL) at the University of California, Berkley to search for extraterrestrial intelligence. Image credit: brewbooks
As far as we know, Earth is the only planet that has been found to actively support life. However, humanity has barely had the opportunity to scour the cosmos. Humans have only been broadcasting radio signals for about 130 years. Radio waves move at the speed of light, so Earth’s current range of influence is a roughly 260-light-year diameter sphere with us at the center (our galaxy alone is 100,000 light years across). Any intelligent lifeforms potentially listening for us outside that sphere are completely unaware of our existence. Organizations like the SETI Institute use both optical and radio telescopes to scour the skies for deliberate signals from advanced extraterrestrial civilizations.
For now, we only have Earth’s flora and fauna to draw from for knowledge of how biology works and how organisms live and propagate. That being said, humans are pretty imaginative. When we look out into the cosmos, we see countless worlds unlike our own. Astrobiology researchers investigate potential worlds beyond Earth that may support life. This includes planets and moons in our own solar system such as Mars and Europa as well as the thousands of exoplanets found around distant stars.
Astrobiologists identify biosignatures such as complex organic compounds, like amino acids and lipids, which are key building blocks of living things. While they can form abiotically (such as in meteorites), it’s hard to form fatty acids and complex chains without life.
They also search for certain isotopic ratios when studying the light spectra of environments. Think of isotopes as “flavors” of elements, like carbon. The biological processes of lifeforms prefer the use of lighter isotopes like carbon-12 over heavier ones like carbon-13 because they are easier to break down (i.e. plant photosynthesis). If we find organic matter in an environment has a shortage of carbon-13 in comparison to the inorganic matter in that same environment, it doesn’t automatically prove the existence of life but is hard to explain through non-biological processes. We also look for similar anomalies in the isotopic ratios of sulfur and nitrogen for similar reasons.
Some worlds seem barren of life now but may have been much different in the past. That’s why astrobiologists search geological samples for microbial fossils. The most directly preserved ones show up as micrometers-sized bubbles, threads or clusters. They are found in very old Earth rocks somewhat regularly, though can sometimes be confused with certain mineral and chemical artifacts. Mars rovers are currently scouring the rocks on the red planet hoping to find the ancient remnants of life from before the planet became a cold, dusty desert.
A big part of astrobiology is speculating about where and how life could survive and challenge our preconceived ideas of what a habitable world can look like. Just because most life on Earth requires oxygen, liquid water and sunlight to survive, doesn’t mean there couldn’t be some alien organisms that can survive, or even prosper, on worlds without one or any of those things. Maybe there are creatures in the dark, subsurface ocean of Europa or within the toxic methane lakes of Titan. Some scientists even consider whether microbial life may be floating around the thick, sulfuric clouds of Venus! Even some Earth creatures are capable of bucking these norms. Take one of Earth’s toughest creatures: the microscopic extremophiles known as tardigrades (aka water bear) which can survive in some of the most uninhabitable places known. They have been observed to survive extreme temperatures, extreme pressures, extreme radiation, extreme salinity among other perils. They have even survived in the vacuum of space. This has made tardigrades a key specimen for astrobiological research. As Ian Malcolm once said: “Life, uh, finds a way.”
Computer Science
Decoding the Universe
Computer simulation showing the cosmic web, a network of filaments stretching between galaxies, believed by many astronomers to form the structure of the universe. Image credit: Andrew Pontzen / Fabio Governato / Hiranya Peiris
The universe is unimaginably vast and complex. Cataloguing its countless stars and galaxies requires processing immense amounts of data. Projects like the Sloan Digital Sky Survey (SDSS) and the Gaia mission amass petabytes of information as they scan large portions of the night sky. Manually analyzing this data is becoming insurmountable. In today’s digital age, computers play a more crucial role than ever before in storing, processing, and interpreting this flood of information.
Computer algorithms follow step-by-step instructions to perform tasks. For example, image processing algorithms can reduce noise and enhance the resolution of telescopic images. Sorting algorithms can organize vast star catalogs by brightness, color, or distance, and help reveal meaningful patterns. For more complex tasks, instead of static algorithms, computers can use machine learning. Instead of being explicitly programmed to solve a problem, computers can learn from examples by identifying common patterns. For instance, if an astronomer wants to classify stars by type (main sequence, giant, white dwarf, etc.), they can train a model on known examples. As the model processes more stars, it improves its ability to recognize each category. Some machine learning methods can even group stars by similarities or detect anomalies without prior examples, uncovering hidden structures in the data.
When predicting outcomes in deeply complex systems over vast timescales, astronomers often rely on computer simulations. These programs create virtual spaces governed by known physical laws (motion, gravity, thermodynamics, electromagnetism, etc.) and populate them with stars, planets, galaxies, or whatever they need. It’s like a sophisticated sandbox video game where astronomers test hypothetical scenarios to observe how different things interact. For example, let’s say we want to simulate a galactic collision. We’ll first need to create a 3D model of two galaxies, each containing millions of stars, gas clouds, and dark matter particles. The simulation then applies the laws of motion and gravity to calculate how every component moves and interacts over millions of years. As the galaxies merge, the program tracks how stars scatter, gas compresses, and new structures like spiral arms or starbursts form, revealing how real galaxy mergers might unfold.
Psychology
The Human Side of Space
The STS-131 crew members pose for a portrait in the Cupola of the International Space Station while Space Shuttle Discovery remains docked. Image credit: NASA
Astronomy and psychology probably seem like total opposites. One looks outward to the cosmos while the other looks inward to the human mind. However, as humanity pushes further and further into space, these two fields are set to reckon with one another. Long-duration manned missions to the Moon, Mars and beyond are receiving more serious consideration and we must consider how the human psyche will bear the weight (or lack thereof). An astronaut ill-equipped to handle the mental rigors of prolonged space travel is not only liable to jeopardize themselves but the mission.
A manned mission to Mars could span two to three years: six to nine months in transit each way, plus one to three months on the surface (while remaining confined to compact, controlled habitats). Even astronauts aboard the International Space Station, typically on six-month missions with less confinement, have shown mental health challenges. Common issues include isolation, sensory deprivation, monotony, disrupted sleep, mood instability, and perceptual difficulties. When selecting crew for missions, space agencies like NASA use psychological profiling and simulations to test candidates ability to work under stress, work with crewmates and display skills in leadership, adaptability and emotional intelligence.
To keep astronauts in peak mental condition, they follow rigid daily routines, learn stress relief techniques and conflict resolution, and perform teamwork exercises. While on mission, astronauts are supported by teams of experts who monitor their condition and offer guidance. While astronauts deal with incredibly long hours with heavy workloads, rest and recreation periods are built into their schedules to prevent burnout. If possible, they may even be able to talk with loved ones back home. Psychologists are also experimenting with new technologies and techniques such as AI-driven companions that can monitor behavior, offer coping strategies and simulate empathetic conversation in real time (the time delay for radio communications between Earth and Mars make it unreliable in emergencies).
Although the challenges of space are very real and potent, space travel does seem to offer a valuable gift to the human condition. When Apollo 14 astronaut Edgar Mitchell spoke of his experiences on the Moon, he said this: “You develop an instant global consciousness, a people orientation, an intense dissatisfaction with the state of the world, and a compulsion to do something about it. From out there on the moon, international politics look so petty. You want to grab a politician by the scruff of the neck and drag him a quarter of a million miles out and say, ‘Look at that, you son of a bitch!”
Many astronauts have expressed similar sentiments of the sobering nature of looking back and seeing the entirety of the Earth and feeling a deep change in their perspective and priority. The preciousness and fragility of our world and our place in the universe seems to inspire a sense of unity. This phenomenon was dubbed the “Overview Effect” by Frank White in his eponymous 1987 book. I feel like I kind of experience something like this when I look out at the Milky Way from a dark sky site or learn a cool new fact about the universe. The feeling of connection that people can have with the universe by looking at the night sky is just as real as the connection that brings astronomy into harmony with all the other sciences. Embrace it and you’ll be rewarded.