“How long is the Earth?” is an unusual question, but let’s explore a thought experiment to find an answer. Imagine cutting the Earth into Minecraft-sized 1-meter cubes and laying them in a line through space. How far would the Earth stretch?

In a fascinating video by astrophysicist Liv Boeree, we discover that the Earth would stretch across the entire Milky Way galaxy if its volume were laid out in a line of 1-meter cubes. That’s more than 100,000 light-years!

This mind-blowing fact illustrates the immense volume of our planet in a unique and captivating way.

Boree says *“Volume is seriously underrated”* and it’s true.

For example, some people can’t get the illustration below – which shows the volume of water on Earth. They think *“70 percent of Earth is covered with oceans, the volume of water (the size of the water spheres below) cannot be that small compared to the volume of Earth”*. But they are wrong – they cannot understand the volume and the math behind its calculation.

I had a few meaningless arguments with some people on LinkedIn about this topic. They just couldn’t visualize the concept of volume in their minds.

People look at the image above and think, *‘Hey, such a small amount of water can’t cover more than 70% of the Earth’s surface.’*

However, the *area* is a measure of the extent of a two-dimensional surface or shape. It’s quantified in square units (e.g., square meters, square kilometers), while volume measures the capacity of a three-dimensional object. It’s quantified in cubic units (e.g., cubic meters, cubic kilometers).

For example, let’s think about a 1-meter square. Its area is 1×1 = 1 square meter, and if we put a cube on it, its volume would be 1x1x1 = 1 cubic meter.

Now let’s double the square’s sides. Now its area is 2×2 = 4 square meters, but a cube on top of it would have a volume of 2x2x2 = 8 cubic meters.

If it was 10 meters x 10 meters square, then we get 100 square meters, but a cube’s volume would be 10x10x10 = 1000 cubic meters!

You can continue forever – for a side of 100 meters, the area would be 10,000 square meters while the volume would be a whopping 1 million cubic meters. That’s 1 million *tonnes* of water if you fill that cube with water!

## Calculations behind the “How LONG is the Earth” video

Earth’s volume is approximately 10^{21} cubic meters. The diameter of the Milky Way galaxy is estimated at around 100,000 light-years, which is approximately 10^{21} meters. Hence, the earth disassembled and rearranged into a single line of 1-meter-sided cubes stretches across our galaxy.

X = √(V/D) = √(10

How LONG is the Earth? If our planet were disassembled and rearranged into a single line of 1 meter-sided cubes, it would stretch across the entire Milky Way galaxy.^{21}/10^{21}) = 1 meter

### Stretching Earth’s Volume Across the Observable Universe

Assuming the observable universe has a diameter of approximately 90 billion light-years, which is about 8.5 x 10^{26} meters (D), and the volume (V) of Earth is approximately 10^{21} cubic meters, to stretch the Earth’s volume across the Observable Universe, the edge length of the cubes required is:

X = √(V/D) = √(10

If the Earth were disassembled and rearranged into a single line of 1.09 millimeter-sided cubes, it would stretch across the entire Observable Universe.^{21}/8.5 x 10^{26}) ≈ 1.09 mm (millimeters)

#### Wait, what is the Observable Universe?

The Observable Universe is the region of the entire Universe that we can see from Earth. This limit is defined by the age of the Universe, which is approximately 13.8 billion years. Since light travels at a finite speed, we can only observe objects whose light has taken up to 13.8 billion years to reach us. This is the maximum time light has had to travel since the beginning of the Universe.

However, the actual distance to these farthest observable objects is greater than 13.8 billion light-years because the Universe has been expanding since the Big Bang. As light travels through space, the space itself stretches, increasing the distance between objects. Consequently, while light has been traveling for 13.8 billion years, the expansion of space means that the objects we are observing are now much farther away than they were when the light first started its journey.

Taking this expansion into account, the diameter of the Observable Universe was calculated at about 90 billion light-years. This means that the light we see from the edges of the observable universe has traveled a vast distance, made even greater by the expanding Universe. Thus, the Observable Universe is just a portion of the entire Universe, constrained by the limits of how far light has traveled and the ongoing expansion of space.

In contrast, the entire Universe includes not only the observable part but also regions beyond our observational reach. These regions are currently beyond our ability to detect because their light hasn’t had enough time to reach us, or they are receding faster than the speed of light due to the Universe’s expansion. Thus, the Observable Universe is just a small portion of the whole Universe, constrained by the limits of our current observational technology and the finite speed of light.

The Universe’s size is unknown, and it may even be infinite in extent – this is another mind-blowing fact!

## Leave a Reply