Human Scale: The Relation to the Observable Universe and Planck Length

The human scale is a fascinating topic when compared to the vastness of the observable universe and the infinitesimal Planck length. This article explores how, in size, the average human being is much closer to the Planck length than to the observable universe, revealing the cosmic perspective and the fundamental nature of space and scale in our universe.

Size Comparison

The average human adult stands approximately 1.7 meters tall, or roughly 170 centimeters. This seemingly large figure becomes minuscule when compared to the observable universe and the Planck length.

Planck Length

The Planck length, a fundamental unit of length derived from the natural constants, stands at approximately 1.6 times 10-35 meters. This incredibly small scale represents the smallest measurable length in the universe, as understood through our current physics.

Observable Universe

The observable universe, stretching a diameter of about 93 billion light-years, equates to roughly 8.8 times 1026 meters. This vast size highlights the contrast between human and cosmic scales.

Proportionality and Comparison

Visually, the size of an average human (1.7 meters) is vastly larger than the Planck length (1.6 times 10-35 meters).

When compared to the observable universe, the difference is even more astounding. At 1.7 meters, a human being is minuscule compared to the 8.8 times 1026 meters diameter of the observable universe.

Thus, while both comparisons are extremely different, the size of an average human being is significantly closer to the Planck length than to the size of the observable universe.

Relative Proximity to the Known Universe

Compared to the Planck length, the difference in magnitude between a human and the known universe is just a few meters (on Earth’s scale) versus 46 billion light-years. This stark difference emphasizes the vastness of space.

Interestingly, the human scale is much closer to the size of the known universe by a factor of about 70 million. This vast difference is easier to grasp by imagining the Earth scaled up to the size of the observable universe, where the Planck length would be the size of the nucleus of an atom.

Conclusion

The scale of human existence is fundamentally linked to the vastness of the observable universe and the infinitesimal Planck length. Understanding this relationship provides insight into the fundamental nature of space, length, and the vastness of our cosmos. While humans seem tiny in cosmic terms, this perspective also underscores the intricate and often mysterious nature of the universe.