The Real Scale of the Universe: Discover the Immensity of Our Cosmic Home

When we start discussing the vastness of the universe, there are certain questions that inevitably come to mind.
One of these questions is, "Are we simply too small, or is the universe just overwhelmingly enormous?"
Indeed, our universe is so incredibly vast that we needed to create special units of measurement just to describe the distances between celestial bodies!
Even within our own solar system, reaching the nearest planet requires months, or even years of travel, and even then, it is merely a single grain of sand in the vast cosmic desert.
Today, we will be discussing the immense scale of the universe.
We'll talk about how much time it would take if you were to move to another planet, and whether it is even possible to travel beyond our solar system in reality.
How long would it take to travel to planets other than Earth?
Every acquaintance you have, every person you love or hate-all beings born on this Earth-start their journey of life on a small blue sphere floating in the dark ocean of space.
Earth is the only place in the universe we can truly call "home."
However, no matter how much we love Earth, our curiosity and thirst for discovery and adventure push us to explore further.
Humanity has only just timidly taken its first small steps into the exploration of nearby space.
Our achievements so far include landing on the moon and meticulously planning a trip to Mars.
We deeply believe that one day, such journeys will become commonplace.
But in the distant future, will we ever be able to travel beyond the Milky Way galaxy?
Unfortunately, the chances appear slim.
This is due to the incredibly vast size of the universe.
To understand the true scale of the universe, let’s start with something smaller: our solar system.
The moon, which is the closest celestial body to Earth, is about 385,000 kilometers away.
If you were to drive a car at a constant speed of 100 kilometers per hour without stopping, it would take you approximately 160 days to reach the moon.
You might wonder, "What was the point of inventing spacecraft?
Wasn't it so that we could travel through space in these vehicles?"
Indeed, you are absolutely correct.
The first human flight to the moon, which took place in 1969, took over three days.
Even with modern rockets, it still takes about the same amount of time to cover that distance.
You might think, "A three-day flight doesn't sound too long, does it?"
But keep in mind, on a cosmic scale, the moon is just a stone's throw away.
Now, let’s imagine Elon Musk finally builds a cutting-edge spaceship and sets off for Mars.
The Distances We Can Never Cross
By now, you might start to think of our solar system as "our grand home."
In that context, the Oort Cloud would be the very threshold of this home.
Crossing this line would mean stepping into an unknown, pitch-dark, and endless world.
Amidst the backdrop of trillions of shimmering dots, a bright light would catch your eye.
This light serves as a beacon, like a lighthouse, guiding and beckoning us forward.
It is the star system of Alpha Centauri, the closest star system to our solar system.
This star system is 41.3 trillion kilometers away from the Sun, equivalent to 276,000 astronomical units.
To describe such vast distances between celestial bodies, we use yet another unit of measurement.
This unit is the "light-year."
A light-year is the distance that light travels in one year.
The speed of light is approximately 300,000 kilometers per second.
One light-year equals 9.461 trillion kilometers.
Now, Alpha Centauri is 4.4 light-years away from us.
Naturally, with our current technology, planning a journey to this star system is impossible.
Why do we have to be so pessimistic about this?
Let’s consider the Voyager space probe for a moment.
This probe travels through space at a speed of 17 kilometers per second.
If we were to send it towards Alpha Centauri, it would take 75,000 years for the probe to reach its destination!
And I repeat, this is the closest star to us...
Even if we were to build a spaceship that could travel at speeds close to the speed of light, it would take 100,000 years to traverse the Milky Way galaxy.
Why We Cannot Measure the Size of the Universe
Many researchers believe that the universe is infinite.
Even if there were limits to the universe, it would be impossible to find them.
At least, not in the near future.
There are also limits to the range we can currently observe.
If an observer stood at the center of our solar system, the observable part of the universe would spread out in a sphere with a diameter of 93 billion light-years.
Imagine someone pointing a flashlight at a dark piece of land from a very high place.
The observable universe is like that.
Beyond the observable limit, there may be something, but it is impossible for us to see it.

[@JM-sz4oi]

Waste of time.