How big is the universe? Discover what scientists have uncovered beyond the dwarf planet Pluto

The universe is generally referred to as infinite, unknown, and limitless. With over 2 trillion galaxies and millions of stars and planets, the universe is so enormous that it stretches the boundaries of human understanding. From cosmic road trip analogies to mind-bending measurement of the universe, here's a closer examination of just how gigantic our universe really is.From the 6,000-year odyssey to Pluto to the outward-horizon frontiers of the observable universe, space isn't just huge; it's unimaginable. Trillions of galaxies, millions of stars, and more mysteries than our imaginations can conjure, the universe simply continues to expand physically and in our understanding of it.To understand just how enormous space is, let's begin with an analogy that's close to home — a road trip. If you could travel in a straight line at highway speed (approximately 60 mph or 100 km/h), the drive to Pluto, which is the outermost farthest-out dwarf planet that defines the edge of our solar system, would take around 6,000 years. That's longer than has passed since the beginning of recorded human existence.And yet, cosmically speaking, Pluto is basically in the neighbourhood. It's merely 5.9 billion kilometers (3.7 billion miles) from our own planet — an infinitesimal distance on the cosmic scale of things.One of the most mind-boggling and perplexing things that we are aware of concerning the universe is that it has no boundary. It is not enclosed by a wall or endpoint where the universe ends. What astronomers refer to as the "observable universe" is just that portion that we can see and observe with light and other radiation.What is out there? That's still one of the biggest secrets of science. The universe could be infinite, or it could curve up in ways we can't yet perceive — like the surface of a four-dimensional sphere. Up until now, everything that's outside the observable universe is beyond scientific measurement.The observable universe has a diameter of approximately 93 billion light-years. To put it in perspective:Even with the world's most advanced telescopes, they are only able to peer into a minuscule percentage of this immense space in the cosmos, and so the rest of the universe goes unvisited and unmapped.There are more than 2 trillion galaxies in this immense observable universe, scientists estimate — each a star city. These are variously shaped and sized, ranging from the stately spirals like our Milky Way to enormous elliptical or disorganised irregular ones.Each galaxy contains millions to billions of stars, and several stars have planetary systems inside them. The observable universe contains more than 100 sextillion observable stars — 1 followed by 23 zeros. This most probably totals trillions of planets, some of which might even possibly be inhabited by life on them. As huge as the universe is already, it keeps expanding every second. This continuous expansion is fueled by an unknown and as yet not entirely comprehended force called dark energy.Whereas gravity squeezes matter together, dark energy pushes space away. It causes galaxies to move apart from one another at increasingly faster rates, opening up the universe outward. This discovery, maintained through the end of the 20th century, reshaped modern cosmology. Briefly, the universe isn't just gigantic and it's increasing in size by the second.Despite incredible technological leaps, human exploration has only begun to graze the surface of what is out there. We've walked on the Moon, launched Mars rovers and shot probes to the limits of our solar system and even these achievements represent only a tiny droplet of cosmic distances.The farthest artificially built object to be placed in space is Voyager 1, which was launched in 1977. It is still in the Milky Way and has travelled approximately 24 billion kilometers—an infinitesimally small distance on a cosmic scale. The scale of the universe is humbling and awe-inspiring. It reminds how tiny we are but how much more there is to discover. With every step towards space travel, we gain more knowledge of where we fit in the universe.Whether we desire extraterrestrial life, more planets, or increased knowledge of physics, our quest into space is only just beginning. And with the modern-day telescope, space travellers, and theoretical research, mankind is at the threshold of discoveries that can redefine everything we know.Also Read | Meet ISRO technician who once was golgappa seller ; know how his late-night studies made his dream a reality