Light has real-time energy transfer,

Romer, based on Io’s orbital period (approximately 1.769 days), observed that eclipses occurred 11 minutes earlier when Earth was closer to Jupiter and 11 minutes later when Earth was farther away. Using this time difference, he calculated that light takes 22 minutes to cross the diameter of Earth’s orbit around the Sun (approximately 186 million miles). From this, he estimated the speed of light to be around 220,000 kilometers per second.

Ole Rømer conducted an experiment and recorded it; now let’s examine what possible factors could be involved.

When Earth is closer to Jupiter, Io appears at a certain time, but when Earth is farther from Jupiter, Io is observed 11 minutes later.

Let’s consider this only when Earth is farther from Jupiter.

First Possibility:

We see Io before it disappears behind Jupiter, then we see Jupiter without Io when it is hidden, and afterward, we see Io reappear near Jupiter. We observe it 11 minutes later than the expected time. Since the light from Jupiter is already arriving late, why does it need to be delayed by an additional 11 minutes? This implies it arrives even later than the delay. Based on this, it seems Ole Rømer must have lied about his experiment.

Second Possibility:

Ole Rømer says he saw Io 11 minutes later. Perhaps when Earth is farther away, Io remains hidden behind Jupiter for an extra 11 minutes before . If that were the case, the delay would keep increasing by 11 minutes with each orbit. However, since it is stated (approximately 1.769 days), this possibility seems unlikely.

Third Possibility:

We are observing Io and Jupiter in real-time before Io disappears. Even after Io disappears, we see Jupiter without Io. When Io reappears, we still see Jupiter. However, Io’s light does not arrive, yet Io continues its journey without stopping. But when the light does arrive, we see Io where it is at that moment. This is my claim.

This claim suggests that Ole Rømer’s observation refers to real-time events. If there are any other possible explanations, please provide them.

He recorded the times when Jupiter’s moon (Io) became visible but did not note the observation locations because he didn’t need to. Let’s imagine this scenario: Look at this picture. (link deleted)

If we were closer to Jupiter, we would see the moon before it reaches position 1.

If light traveled with the event (carrying its history), we would observe the same delay from Earth. Ole Rømer would have seen no difference.

But he did observe differences:

When Earth was near Jupiter, the moon appeared at position 8.

When Earth was farthest from Jupiter, the moon appeared at position 9.

He used this discrepancy to calculate the speed of light.

Key Insight:

We only see Jupiter’s moon after its light reaches us—not its position when the light was emitted. For example:

We cannot see the moon moving from positions 0 to 7 because that light hasn’t reached us yet.

When the light arrives, we see the moon’s current position, not where it was when the light began its journey.

1 hour ago, jalaldn said:

Look at this picture

Moderator Note

You can upload and display pictures, which is preferable to a link. But using a link shortener is a no-no, since nobody can tell what the destination is

1 hour ago, jalaldn said:

We only see Jupiter’s moon after its light reaches us—not its position when the light was emitted. For example:

An incorrect location of the moon is, at worst, a small error in the calculation, which you are free to calculate. The important thing is the position of Jupiter relative to earth.

Since the light from Jupiter is already arriving late, why does it need to be delayed by an additional 11 minutes?

Not sure what tortured logic is involved here. It doesn’t “need to be delayed” it is observed at a certain time.

Anyway, we have many, many other measurements of the speed of light, and relativity, which incorporates issues of simultaneity, is a well-tested theory. You’re tilting at a windmill here.

3 hours ago, jalaldn said:

When Earth was near Jupiter, the moon appeared at position 8.

When Earth was farthest from Jupiter, the moon appeared at position 9

Why would anyone think that?

The moon is occulted by Jupiter. It appears at 1 and, as I noted, even appearing at 8 or 9 would have minimal effect on the experiment. In physics we quantify things. Do the math.

Io is about 350,000 km above the surface.Jupiter’s radius is about 70,000 km.

i.e. the light travel time from surface to its moon is about 1 second