How big is the Universe?
Are we the only ones?
Earth, our home planet, is a tiny blue dot floating in the immense cosmic ocean. Here resides everyone you ever knew, every human who ever lived, and every story ever told. This is where our journey begins. As we zoom out beyond our atmosphere, past the Moon, beyond the familiar planets and the Sun, we embark on an epic quest—a quest to grasp the true scale of our universe.
Leaving Earth's embrace, our first marker on this cosmic journey is the Moon, about 384,000 km away. This distance is so vast that if you were to drive a car at a constant speed of 100 km per hour, it would take you over 160 days to reach it. From this lunar vantage point, Earth appears as a fragile sphere of blues and greens cradled in the black void of space, a sight that puts our existence into a humbling perspective.
As we continue outward, the next milestone is the Sun, approximately one astronomical unit (AU) away from Earth. This unit, equivalent to about 150 million kilometers, is the standard measure for distances in our solar system. Light, traveling at 300,000 km/s, takes about 8 minutes and 20 seconds to journey from the Sun to Earth. If you were to travel this distance in a commercial jet flying at 900 km/h, it would take about 19 years. This immense distance is a stark reminder of the vastness of space, even within our own solar system. The Sun, a fiery behemoth, provides life-sustaining energy to our planet from this incredible distance.
Venturing beyond our home planet and its solar companion, we set our sights on Mars, our enigmatic red neighbor. Mars, at its closest approach to Earth, is about 54.6 million kilometers away, but this distance can stretch up to 401 million kilometers when the two planets are on opposite sides of the Sun. Traveling to Mars at the speed of a commercial jet would take upwards of 50 years. This vast expanse between Earth and Mars presents significant challenges for space exploration. The rovers and probes we've sent to the red planet embark on a journey that is not just far but fraught with complexities due to the constantly changing distances and orbital dynamics.
As we journey to the outermost reaches of our solar system, we encounter Neptune, the distant ice giant, lying roughly 4.5 billion kilometers from Earth. Neptune marks the edge of our solar neighborhood. Sunlight racing across the vacuum of space takes about 4 hours and 15 minutes to reach Neptune from the Sun. This staggering distance showcases the enormity of our solar system. Launched in 1977, the Voyager 1 space probe represents humanity's insatiable curiosity and desire to explore beyond known boundaries. As of now, Voyager 1 has traveled for over four decades, covering a staggering distance of more than 22 billion kilometers from Earth. It is the farthest human-made object from our planet, a silent wanderer in the cosmic sea.
In 1990, at the suggestion of the renowned astronomer Carl Sagan, Voyager 1 turned its camera back towards Earth for one final photograph. This resulted in the iconic "Pale Blue Dot" image. At a distance of about 6 billion kilometers, Earth appeared as a tiny faint dot in the vastness of space. Sagan poetically reflected on this image, emphasizing our responsibility to cherish and preserve our only home—a small speck in the immense universe.
At the very fringes of our solar system lies the Oort Cloud, a vast theoretical sphere of icy objects. This distant cloud is thought to extend up to a staggering 100,000 astronomical units from the Sun, or about 1.9 light-years—a distance so immense that it's on the cusp of interstellar space. Scientists determine the boundary of interstellar space, known as the heliopause, where the Sun's solar wind is stopped by the interstellar medium. This is where the influence of our Sun ceases, and the vast realm of interstellar space begins. The Oort Cloud represents the final frontier of our solar system, a boundary zone where the Sun's influence wanes, and the cosmic journey into the galaxy truly begins.
Beyond the confines of our solar system, our next point of interest is Alpha Centauri, the closest star system to our Sun. Located about 41.3 trillion kilometers away, this distance is equivalent to over 276,000 astronomical units. At such colossal distances, the AU, a convenient measure within our solar system, loses its practicality. Hence, astronomers use the light-year—the distance light travels in one year—for interstellar measurements. Alpha Centauri is about 4.4 light-years away from us. Considering our current space travel technology, a journey to Alpha Centauri is almost unfathomable. For instance, the Voyager spacecraft, traveling at about 17 km/s, would take over 70,000 years to reach this neighboring star system. This immense distance underscores the vastness of space that separates the stars and highlights the challenges of interstellar travel.
Our journey now takes us to the grand scale of our home galaxy, the Milky Way. Spanning about 100,000 light-years in diameter, this vast spiral galaxy is home to hundreds of billions of stars, each potentially hosting their own planetary systems. Within this immense structure, there is a tiny sphere known as the human radio bubble, extending about 100 light-years from Earth. This bubble represents the farthest extent of human influence in the cosmos—the reach of our radio and television broadcasts into space. Beyond this bubble, it's as if humanity never existed. Any civilizations residing in the vast majority of our galaxy would be oblivious to our presence, given that our signals haven't reached them yet. The scale of the Milky Way is so vast that our entire recorded history is but a whisper in the cosmic wind, undetectable beyond this small bubble.
As we leave the Milky Way, we enter the vast, almost incomprehensible realm of intergalactic space, where galaxies float in the cosmic ocean, separated by mind-boggling distances. Our galaxy is part of a small cosmic neighborhood known as the Local Group, a cluster of more than 50 galaxies spread across approximately 10 million light-years. The Local Group is a diverse assembly, including not just spiral galaxies like the Milky Way and Andromeda, but also a multitude of smaller dwarf galaxies. The distances here are so vast that light from one end of the Local Group to the other would take 10 million years to traverse. This scale dwarfs anything within our own galaxy, underscoring the enormity of the universe. Intergalactic space is a silent expanse, a vast wilderness between the islands of galactic light. In this immense void, our galaxy, home to our entire history, is just a tiny speck among many—a single story in the grand cosmic library.
As we extend our cosmic gaze beyond the Local Group, we encounter the colossal Virgo Supercluster, an immense collection of galaxy groups and clusters, including our own Local Group. Encompassing a region of space about 110 million light-years in diameter, or 33 megaparsecs, the Virgo Supercluster is a titanic structure in the universe, containing thousands of galaxies from at least 100 galaxy groups and clusters, each with their own myriad stars and planets.
Journeying outward from the Virgo Supercluster, we arrive at an even more staggering cosmic structure—the Laniakea Supercluster. This immense congregation of galaxies, which includes the Virgo Supercluster and extends over 500 million light-years, is our galactic home on a grand scale. Laniakea, meaning "immense heaven" in Hawaiian, truly lives up to its name, containing the mass of 100 million billion Suns. Laniakea is a gravitational masterpiece, with galaxy clusters, superclusters, and countless celestial bodies bound in a cosmic web of attraction and motion. At the heart of Laniakea lies the Great Attractor, a mysterious region of space that exerts a massive gravitational pull on the galaxies within this supercluster. In this vast expanse, our Milky Way, the entire Local Group, and even the Virgo Supercluster are just tiny components of this gigantic structure. Laniakea provides a profound context for our existence—in this immense supercluster, we are part of something far greater and more majestic than we can fully comprehend.
Reaching the boundaries of our cosmic exploration, we encounter the limits of the observable universe—an astronomical marvel stretching about 93 billion light-years in diameter. This begs a fascinating question: if the universe is only 13.8 billion years old, how can it be so vast? The answer lies in the nature of cosmic expansion. The universe has been expanding since the Big Bang, stretching space and increasing distances between celestial bodies. But what lies beyond the observable universe remains one of the greatest mysteries of cosmology. Some regions of space are expanding away from us faster than the speed of light, placing them forever out of our view. Consequently, the true size of the entire universe remains unknown and potentially infinite.
About the Creator
Keep reading
More stories from Shinzou Wo sasageyo and writers in Earth and other communities.
what if earth collided with Mars?
Mars has been on a direct collision course with Earth for weeks, causing massive tsunamis and earthquakes. Our planet's crust is cracking, and gravity is changing significantly. But how bad will this get? Could it create a new planet? Is there any way humans could survive? Let's find out what would happen if Earth collided with Mars, starting 15 days before impact.
By Shinzou Wo sasageyoabout a year ago in Earth
Britain’s PM Calls Trump on Greenland: Defending Sovereignty in a Shifting Arctic
When you think of New Year’s conversations between world leaders, Greenland probably isn’t the first thing that comes to mind. Yet on January 7, 2026, British Prime Minister Keir Starmer and former U.S. President Donald Trump discussed the icy island over a phone call — and it made headlines worldwide. Why? Because Greenland, a massive, ice-covered territory in the Arctic, is suddenly at the center of global geopolitics, and Britain is making sure its voice is heard. Greenland Isn’t Just Ice At first glance, Greenland seems remote and quiet — a land of snow, glaciers, and polar bears. But this island is strategically critical. It sits between North America and Europe, holds valuable natural resources, and commands control over emerging Arctic shipping routes as ice melts due to climate change. In recent years, Greenland has captured the attention of global powers, especially the United States. Trump has repeatedly suggested that the island is crucial to U.S. national security and even hinted at the possibility of acquiring it. These ideas, though unlikely, raised eyebrows in Europe and among NATO allies. For Denmark, Greenland’s governing country, and its residents, this rhetoric was a reminder that sovereignty matters — and outsiders shouldn’t dictate their future. Starmer’s Clear Message During the phone call, Starmer made Britain’s position unmistakable: Greenland’s future must be decided by its people and Denmark, not by external powers. This wasn’t just diplomacy for the sake of headlines. It’s about principles that Britain has long defended: respect for sovereignty, international law, and the rules-based global order. Starmer’s message sends a signal not only to Trump but also to other countries that might think about exerting undue influence over smaller, strategic territories. The call also touched on other global concerns, including NATO security matters, Arctic maritime operations, and broader geopolitical tensions. But it’s Greenland that grabbed the spotlight — because it’s a flashpoint for sovereignty, alliance dynamics, and Arctic strategy. Why the UK Cares You might wonder: why is Britain involved in a discussion about Greenland? After all, it’s part of Denmark. The answer lies in NATO and European security. Greenland is strategically vital for the alliance. Any unilateral action by the U.S. to control or influence Greenland could threaten NATO cohesion. Britain, as a leading NATO member, has a stake in ensuring that all alliance decisions respect sovereignty and the rules of international cooperation. In other words, Britain isn’t stepping into Greenland’s affairs to take control — it’s defending the principle that territorial decisions should belong to the rightful authorities, in this case, Denmark and Greenland’s residents. Alliances and Principles Starmer’s call also highlights a delicate balancing act. The UK maintains a close relationship with the U.S., but that doesn’t mean it agrees with every idea, especially when sovereignty is at stake. This is the reality of modern diplomacy: even trusted allies can have differences of opinion, and leaders must navigate these differences carefully. Starmer’s message to Trump reflects a wider approach — maintain strong alliances while standing firm on core values. Some politicians have acknowledged that disagreements are normal and even healthy in long-standing partnerships. The key is open communication and respect for international norms, which Starmer aimed to demonstrate during the call. Greenland as a Symbol Beyond geopolitics, Greenland has become a symbol of a new era in global relations. Arctic resources, strategic positions, and climate change are making previously quiet regions hotspots for diplomacy. Greenland reminds the world that territory, sovereignty, and self-determination are still central issues, even in the 21st century. For Britain, standing with Denmark and affirming Greenland’s autonomy sends a clear message: the UK supports international law and the idea that small regions should not be pawns in great-power games. What This Means Going Forward So what can we expect after this phone call? Greenland remains firmly under Danish control, with its future in the hands of its residents. NATO cohesion is reinforced, as European leaders see Britain advocating for rules-based governance. The Arctic region continues to be a strategic focal point, with countries carefully watching each other’s moves. In short, Starmer’s call is a reminder that even in a world of powerful nations, diplomacy, respect, and legal principles still matter. Takeaways Sovereignty Matters: Greenland’s future is a matter for its people, not outside powers. Allies Can Disagree: Britain’s defense of principles shows that disagreements with allies don’t have to break partnerships. Strategic Regions Are Hotspots: Arctic regions like Greenland are increasingly important in global security, economics, and diplomacy. Principles Over Power: Upholding international law is as critical as maintaining military or economic influence. Greenland may be far from the streets of London or Washington, but the stakes are high. Starmer’s phone call with Trump demonstrates that the UK is ready to defend sovereignty, international norms, and alliance cohesion, even when the conversation turns icy.
By Muhammad Hassan6 days ago in Earth
Fly-Arousing Orchid and Zombie Fungus Among 2025’s Most Astonishing Botanical and Fungal Finds
Nature never stops surprising us. In 2025, botanists and mycologists around the world unveiled a collection of discoveries so strange they sound almost fictional. From a fly-arousing orchid that mimics insects with unsettling precision to a “zombie” fungus capable of hijacking its host, these finds highlight how much of Earth’s biodiversity still remains hidden — and how creative evolution can be. These discoveries are not just curiosities for scientists. They offer deeper insight into pollination, survival strategies, ecosystem balance, and even potential medical breakthroughs. Together, they remind us that even in an age of satellites and AI, nature still holds countless secrets waiting to be uncovered. The Fly-Arousing Orchid: Seduction as a Survival Strategy Among the most talked-about discoveries of 2025 is a newly identified orchid species that has taken deceptive pollination to a whole new level. Found in a remote region with limited insect diversity, this orchid doesn’t attract pollinators with nectar or bright colors. Instead, it sexually deceives male flies. The flower closely resembles the shape, texture, and scent of a female fly, producing chemical signals that trigger mating behavior in unsuspecting males. Drawn in by false promises, the flies attempt to mate with the flower — a process known as pseudocopulation. During this encounter, pollen sticks to the insect’s body and is later transferred to another orchid, completing the plant’s reproductive cycle. While similar strategies have been observed in some orchid species before, researchers say this one is unusually sophisticated. Its scent profile is so precise that it targets only one specific fly species, making the relationship incredibly specialized — and fragile. Why This Orchid Matters Beyond its shock value, the fly-arousing orchid provides important lessons about coevolution. Over thousands of years, the orchid and its pollinator appear to have shaped each other’s survival strategies. This level of specialization demonstrates both the brilliance and vulnerability of nature. If the fly species declines due to climate change, habitat loss, or pollution, the orchid could face extinction. Scientists say this discovery underscores why biodiversity conservation must consider entire ecological relationships, not just individual species. The “Zombie” Fungus: When Nature Takes Control Equally unsettling — and fascinating — is the discovery of a new fungal species quickly nicknamed a “zombie fungus.” Found in tropical forest ecosystems, this fungus infects small insects and gradually alters their behavior to serve its own reproductive needs. Once inside the host, the fungus releases chemical signals that affect the insect’s nervous system. The infected insect abandons its normal behavior, climbing to an elevated position before dying. From there, the fungus grows outward, releasing spores that rain down on potential new hosts below. This mind-controlling behavior has drawn comparisons to well-known parasitic fungi, but researchers say the 2025 discovery displays previously undocumented precision in behavioral manipulation. Why Scientists Are Excited — Not Horrified While the term “zombie fungus” captures public attention, scientists are more interested in its biochemical mechanisms. Understanding how the fungus influences nervous systems could open doors to: New antibiotics or antifungal treatments Insights into neurological signaling Natural alternatives to chemical pesticides Fungi have already contributed to major medical advances, including penicillin. Discoveries like this reinforce the idea that nature’s strangest organisms may hold the most valuable solutions. Other Remarkable Botanical and Fungal Finds of 2025 The fly-arousing orchid and zombie fungus are only part of a much larger picture. In 2025, researchers also documented: Carnivorous Plants with Improved “Traps” New species of carnivorous plants were discovered using faster and more efficient trapping mechanisms, allowing them to survive in nutrient-poor soils. Glow-Enhancing Bioluminescent Fungi Scientists identified fungi with unusually bright natural bioluminescence, potentially useful for sustainable lighting research and environmental monitoring. Climate-Resilient Plants Several newly cataloged plant species showed remarkable resistance to drought and extreme temperatures, offering hope for future agricultural innovation. Each discovery adds a piece to the puzzle of how life adapts to changing environments. What These Discoveries Say About Our Planet One of the most striking takeaways from 2025’s discoveries is how much remains unexplored, especially in remote forests, underground ecosystems, and tropical regions. Scientists estimate that millions of fungal species alone have yet to be identified. These findings also highlight an uncomfortable truth: many species are being discovered at the same time they are being threatened. Habitat destruction, climate change, and pollution could wipe out organisms before we even understand their role in nature. The Role of Technology in Modern Discovery Advances in DNA sequencing, satellite mapping, and AI-assisted analysis played a major role in these discoveries. Scientists can now identify new species more quickly and understand their relationships within ecosystems with greater accuracy. However, technology alone is not enough. Field research, conservation funding, and local knowledge remain essential to uncovering and protecting Earth’s hidden biodiversity. Why the Public Should Care It’s easy to dismiss bizarre plants and fungi as scientific oddities. But history shows that today’s curiosities often become tomorrow’s breakthroughs. From medicines to sustainable materials, many human innovations began with close observation of nature. The fly-arousing orchid teaches us about communication and deception in evolution, while zombie fungi may help us understand disease control and neurological processes. Protecting biodiversity isn’t just about saving nature — it’s about safeguarding humanity’s future. Conclusion: Nature Is Stranger — and Smarter — Than We Imagine The botanical and fungal discoveries of 2025 remind us that the natural world is far more inventive than fiction. From seductive orchids to mind-controlling fungi, evolution has crafted solutions that challenge our understanding of life itself. As scientists continue to explore Earth’s hidden corners, one thing becomes clear: we are only beginning to understand the complexity beneath our feet and above our heads. Preserving these ecosystems ensures that nature’s most astonishing stories — and solutions — are not lost before they are told.
By Muhammad Hassan6 days ago in Earth
Comments