Chapter 537 252: Turn His World Upside Down!! (8.8K)

"What, Mr. Huygens' calculation of the light speed is incorrect?"

Hearing Xu Yun's words,

Faraday was stunned.

It is well known.

The unit of light speed is very large, so the presence of an error is quite normal, even inevitable.

Not mentioning anything else.

Just compare the results calculated by Huygens and Little Niu.

One is 212,000 kilometers per second, and the other is 210,000 kilometers per second, a difference of 2,000 kilometers.

But the error Xu Yun spoke of that needed correction was obviously not just a minor numerical discrepancy.

The error he referred to was undoubtedly at the 'magnitude' level, at least over 20%.

But...

How is this possible?

To know.

Unlike the exploration of the essence of light.

Because the speed of light is so fast that in everyday life, people cannot perceive that it takes time for light to travel from point A to point B.

Therefore, in the ancient world, both in the East and the West, our ancestors basically had no concept of light speed.

This seemingly common-sense notion persisted until the 17th century when Galileo questioned it and designed an experiment.

Galileo's experiment was like this:

Two people each held a lantern and stood on two hilltops, covering the lanterns with a shutter.

Then.

One person removed the shutter over his lantern.

The person on the opposite hill, upon seeing the light, immediately removed the shutter over their lantern as well.

The first person then recorded the time from removing the shutter to seeing the other person's lantern light. This is the time it took for light to travel back and forth between the two hilltops.

By dividing the distance between the two hilltops by the time, you could theoretically get the speed of light.

Undoubtedly, this experiment ultimately failed.

Because if the distance between the two hilltops is assumed to be one kilometer, the light would need only 0.0000067 seconds to travel back and forth.

Human reaction time generally lies within zero-point-something seconds, which is 30,000 times the time needed for light to travel between the hills.

So no matter how Galileo measured it, he only ended up measuring the reaction time of the two people involved.

Thus, Galileo ultimately abandoned the notion of calculating the light speed, and humanity's first attempt to measure light speed ended in failure.

But Galileo wasn't the only genius among humans. Twenty years after his death, someone thought of a method to measure light speed.

This person's name also included "R," which was Romer, a Danish astronomer.

Earlier, while observing the universe, Romer noticed that Jupiter had a moon called "Io"—Jupiter's moon Io.

During that era.

The advancement of astronomy had enabled people to calculate the orbital period of this moon around Jupiter and determine the exact time it could be observed from Earth.

Romer keenly realized that throughout a year, the distance between Earth and Jupiter constantly changes.

So the time for Io's light to reach Earth also varied.

The time differences observed from Earth were precisely the time disparities due to light traveling over different distances.

Later, Romer discovered through prolonged observations that:

When Earth and Jupiter are nearest, Io appeared 11 minutes earlier than the average time.

When Earth and Jupiter are farthest away, Io appeared 11 minutes later than the average time.

11+11=22.

In other words.

This 22-minute discrepancy was the time difference that light travels over the greatest and smallest distances between Earth and Jupiter, which could be used to calculate the light speed.

The vast expanse of the cosmos provided humans with a large enough scale to calculate this number.

Thus.

Romer publicly presented this hypothesis along with the corresponding observational data in 1676.

However, Romer himself didn't calculate a specific value; the final calculation was done by the mentioned Huygens, who concluded the light speed to be 212,000 kilometers per second.

Little Niu mentioned a similar figure in his "Optics," though he didn't disclose his method, and it's generally considered he likely referenced Romer's data.

Of course.

Given Little Niu's historical disposition, even if he did reference it, he wouldn't admit it.

In any case.

With Little Niu and Huygens' calculated results backing it, the concept of light speed as 212,000 kilometers per second was long considered a truth within the scientific community.

Although there had been cases like Bradley, who calculated light speed to be over 300,000 through his alternative approach using stellar light travel time method.

But since the calculation involved orbits, which had too many logical flaws, it was never accepted by the mainstream.

So upon hearing Xu Yun's phrase 'correcting an error,' Faraday instinctively wanted to refute it.

But before he could speak, another thought emerged in his mind:

The data Xu Yun held could very well be calculated by Fat Fish.

That was Fat Fish after all...

The collision of two emotions in his mind caused Lafayette's expression to become somewhat uncertain.

After a while.

He took a deep look at Xu Yun, silently left the tent, opting to wait and see.

....

The winter days darken quickly.

Less than half an hour after Faraday left, the sky began to grow dark.

After a while.

William Whewell sent someone over with bread and milk.

Around the sealed road, a gathering crowd of curious students began to form.