Take a moment to look around. Where are you? Perhaps you’re in a room, within a city, on a continent, on a planet orbiting a star in a galaxy among billions. But where is all of that? While this might seem like a simple question, the concept of an absolute position is a human construct.
The universe is essentially a vast expanse filled with various entities. If we were to remove all these entities—stars, planets, black holes, and dust—what would remain is empty space. In such a void, the idea of having a position becomes meaningless. Empty space is uniform and consistent everywhere.
Unlike a stage beneath our feet, space cannot be marked with specific points or anchored with staples. Without objects, there is no position. Our location is always relative to something else, which means even concepts like “up” and “down” are relative.
Let’s reintroduce the universe’s contents and attempt to determine our current location relative to everything else. From your perspective, the world appears flat, and you can move in three dimensions. This is known as a “frame of reference”—your unique perspective of the universe and how you perceive movement around you. Your frame of reference is valid for you, but not for the rest of the universe.
About five kilometers away, where the horizon begins, the ground curves away from you. If you could see through the ground, you’d observe people from below or sideways. They don’t fall “down” off the planet because gravity doesn’t pull them down. “Down” is an illusion of your reference frame. To Earth’s reference frame, gravity simply pulls inward.
For humans, there is an up and down because it makes sense within our frame of reference. This is why we believe the planet itself has an up and down, north and south, and we create maps accordingly. However, an observer of the solar system might disagree. Our maps make sense to us because we are accustomed to them, not because they are correct.
This is the first step—your position on what feels like a flat surface but is actually a sphere. This sphere is constantly moving, never staying in one place. Earth orbits a star, the sun, at the center of the solar system.
While we often imagine this as orderly, an outside observer would see something quite chaotic. To illustrate this, let’s exaggerate these movements. Our orbit is an ellipse, so we spend half the year moving closer to the sun, speeding up, and the other half moving away, slowing down. The ellipse changes shape every 100,000 years, and in another cycle of 112,000 years, it drifts, creating a beautiful pattern. The moon complicates things further.
The moon, being massive, exerts a gravitational pull on Earth. Both objects orbit their common center of gravity, located about 4,700 km from Earth’s core. This means that as the moon orbits Earth, it causes Earth to jiggle slightly.
You’re standing on a rotating planet, jiggling around the sun in an elliptical orbit that changes annually. But who’s to say Earth is correct? From the sun’s perspective, the solar system’s plane is arbitrary, defined by Earth’s orbit for convenience. In reality, other planets are slightly inclined relative to our plane. From their viewpoint, we’re the ones with a bent orbit.
The solar system orbits the center of the Milky Way galaxy every 230 million years. However, the plane of the solar system isn’t aligned with the galactic plane. Like planets orbiting the sun on their own planes, stars orbit the galactic center on theirs. The solar system is tilted about 60 degrees toward the galactic plane, speeding through space at nearly a million kilometers per hour.
Someone at the galaxy’s center would see the planets’ orbits moving through space in a helix shape, resembling a corkscrew motion on the tilted plane of the solar system, relative to the galactic plane. This orientation means that sometimes planets are in front of the sun as it orbits the galactic core.
There’s a strange beauty in how our planets and the sun move through space. But this isn’t the whole story. The galactic disk’s mass constantly pulls on the solar system. Like a drunk dolphin, we’re diving and shooting up hundreds of light-years through the galactic plane, ten times every orbit, along arcs thousands of light-years long.
We haven’t fully mapped this motion, as it takes the solar system tens of millions of years to complete one cycle, and humanity is relatively young. Let’s revisit your relative position: on a planet tilted toward the sun, jiggled by the moon, in a solar system tilted toward the galactic plane, moving forward in a helical shape, diving up and down through the plane.
But where is “up” in a galaxy? At this scale, the frame of reference becomes arbitrary and pointless. The Milky Way is part of a galaxy group within larger structures like the Laniakea Supercluster, which is part of the Pisces–Cetus Supercluster Complex, and finally, a galactic filament spanning hundreds of millions of light-years in all directions.
From such a distance, everything appears homogeneous, just like empty space. When everything looks the same, no one’s view is superior. We’ve reached the end of our cosmic journey.
Let’s retrace our steps: from the indescribably large to the really large, to our galactic home, to our galaxy, to the solar system diving through the Milky Way, to the jiggle of existence, and finally, back to you, right now, reading this article.
If this seems overwhelming, don’t worry. The universe’s scale is mind-boggling, and keeping track of everything’s orientation is challenging. But it doesn’t matter. You’re already in the best spot you could be—right here, right now. For all you care, nothing can stop you from being at the center of your own little universe.
Using everyday materials, create a scale model of the solar system. Calculate the distances between planets and their sizes relative to each other. This will help you visualize the vastness of space and the relative positions of celestial bodies.
Use a globe and a flashlight to simulate the Earth’s rotation and orbit around the sun. Observe how the tilt of the Earth affects the seasons and how the moon’s gravitational pull causes tides. This activity will give you a better understanding of the Earth’s dynamic position in space.
Conduct an experiment to understand frames of reference by observing a moving object from different perspectives. Record how the object’s motion appears to change based on your position. This will help you grasp the concept of relative motion in the universe.
Research and create a presentation on the structure of the Milky Way galaxy. Include information about its spiral arms, the galactic core, and our solar system’s position within it. This will enhance your understanding of our place in the galaxy.
Create a visual representation of the cosmic web, including galaxy clusters and superclusters. Use string and pins on a board to map out the connections between these massive structures. This will help you appreciate the scale and interconnectedness of the universe.
Universe – The universe is the vast, all-encompassing space that includes everything that exists, such as galaxies, stars, planets, and all forms of matter and energy. – Example sentence: Scientists study the universe to understand how it began and how it continues to evolve.
Space – Space is the boundless three-dimensional extent in which objects and events occur and have relative position and direction. – Example sentence: Astronauts travel to space to conduct experiments that cannot be done on Earth.
Gravity – Gravity is the force that attracts two bodies toward each other, typically noticeable as the force that gives weight to objects and causes them to fall to the ground. – Example sentence: Gravity is what keeps the planets in orbit around the Sun.
Orbit – An orbit is the curved path of a celestial object or spacecraft around a star, planet, or moon, especially a periodic elliptical revolution. – Example sentence: The Earth completes one orbit around the Sun every 365 days.
Solar – Solar refers to anything related to the Sun, often used to describe energy or phenomena originating from the Sun. – Example sentence: Solar panels convert sunlight into electricity, providing a renewable energy source.
Galaxy – A galaxy is a massive system of stars, stellar remnants, interstellar gas, dust, and dark matter, bound together by gravity. – Example sentence: The Milky Way is the galaxy that contains our solar system.
Motion – Motion is the change in position of an object over time, relative to a reference point. – Example sentence: The motion of the planets around the Sun is governed by gravitational forces.
Reference – In physics, a reference point is a fixed point used to determine the position or motion of an object. – Example sentence: When describing the motion of a car, the ground is often used as a reference point.
Planets – Planets are celestial bodies that orbit a star, are massive enough to be rounded by their own gravity, and have cleared their orbital path of other debris. – Example sentence: The eight planets in our solar system each have unique characteristics and atmospheres.
Stars – Stars are luminous celestial bodies made of plasma, held together by gravity, and generate light and heat through nuclear fusion reactions in their cores. – Example sentence: Stars are born in nebulae and can live for billions of years before ending their life cycle.
