A Response to the Geocentrism Challenge
of Robert Sungenis
of Catholic Apologetics International

First, the Challenge offered by Robert Sungenis:

CAI will write a check for $1,000 to the first person who can prove that the earth revolves around the sun. (If you lose, then we ask that you make a donation to the apostolate of CAI). Obviously, we at CAI don't think anyone CAN prove it, and thus we can offer such a generous reward. In fact, we may up the ante in the near future.

You can submit your "proofs" to our e-mail address cairomeo@aol.com. We will then offer a response. Both your "proof" and our response will be posted on the CAI science page at our website. If you do not want your actual name listed, we will change your name, but your contents will be posted. If you do not want either your name or your contents posted, then you are not eligible for a reply from CAI nor the $1,000 reward. CAI will be the sole judge of whether you have successfully proven your case. But since CAI is built on its reputation of honesty and truthfulness, rest assured that if you do indeed prove your case, you will be rewarded the money.

Now a word of caution. By "proof" we mean that your explanations must be direct, observable, physical, natural, repeatable, unambiguous and comprehensive. We don't want hearsay, popular opinion, "expert" testimony, majority vote, personal conviction, organizational rulings, superficial analogies, appeals to "simplicity," "apologies" to Galileo, or any other indirect means of persuasion which do not qualify as scientific proof.

The $1,000 Challenge will go on indefinitely. So, if you're up for the challenge, take your best shot!

Here is the page at CAI, which also explains why the challenge is being offered.

Submitted to CAI on 15 November 2002:

In reply I offer the following brief RealVideo clip:  Kepler Finds Earth's Orbit Around the Sun
It is a clip from a program titled The Mechanical Universe - Kepler's Three Laws, and is copyright 1985 by the California Institute of Technology.

Regarding your conditions of the proof:

So I release you from the need to pay off based on this video clip, even if you decide to concede heliocentrism based on it alone, as unlikely as I think that may be (unless, of course you just feel irresistibly compelled to divest yourself of your $1000 with less than 100% of your conditions being met absolutely).

However, I do feel that this clip provides very strong evidence that the proof you require does exist, and perhaps someone who is an astrophysicist will be able to simplify the explanation enough to confirm the proof to you, though you may still be able to come up with some fantastic scenario that you feel is able to make it conform to geocentrism.

Conduct your own "experiment"

At the following web site you can, in a sense, duplicate Kepler's observations:

1. Enter 55P in the "Object Name" box.
2. Press "Search" button.
3. Press "Show Orbit" button.
4. Run the simulation to the following dates ( I have already done this, so you can just click on the links to see the results.)

Oct 7, 2003
Aug 24, 2005
Jul 12, 2007
May 29, 2009

So, the results for those four dates are all plotted on this graphic:

Now the following can be seen above:

Observations are made on the day that Mars returns to the exact same point in its orbit (here when it crosses the yellow line at the right. On those dates both the Sun and Mars are at the same fixed relative points, with the same distance between them. The Earth's position changes relative to both the Sun and Mars, tracing out an orbit around the Sun (proving heliocentrism).

(The blue orbital path is that of the comet Tempel-Tuttle, the dust trail of which is responsible for the Leonid meteor showers in mid-November each year. It can be ignored for the purposes of this study.)

Other points worth noting.

Geocentrism Challenge Submissions Page at CAI

Robert Sungenis' reply of 20 Nov 2002:

Michael, thank you for your submission. But I'm sorry to have to tell you that your diagrams don't at all prove your contention.

First, you might want to read up on the relationship between Kepler and Tycho Brahe. You will find that it was Brahe who made all the meticulous chartings of the planets, not Kepler. Kepler actually confiscated Brahe's work after Brahe died. While Brahe was alive, he was using those very calculations to show that Geocentrism was the correct model. Before he died, Brahe insisted that Kepler use the calculations to continue the Geocentric position. Kepler, however, was influenced by other things. Since he was heavily into the occult, as was his mother, he was searching for "musical harmony" among the heavenly bodies. It was his opinion that a solar centered system coincided with that "musical harmony" as opposed to a geo-centered system. As such, Kepler's choice had little to do with evidence disproving the Geocentrism. The fact still remains that both Heliocentrism and Geocentrism work, mathematically and physically. Kepler's findings do nothing to disprove that fact.

Second, we have already dealt with Kepler's claims in our Science posts. I suggest that you consult them.

The first is at www.catholicintl.com/epologetics/geo25.html.

You wrote:

"Now the following can be seen above: Observations are made on the day that Mars returns to the exact same point in its orbit (here when it crosses the yellow line at the right. On those dates both the Sun and Mars are at the same fixed relative points, with the same distance between them. The Earth's position changes relative to both the Sun and Mars, tracing out an orbit around the Sun (proving heliocentrism).

This is nothing more than the retrograde motion of Mars as seen from earth. If you go to our posting on this subject you will see how retrograde motion is explained in the Geocentric system, which is at


You then write:

"Other points worth noting. Venus and Mercury are never observed very far from the Sun. Venus is always observed within 46 and Mercury within 28, so they are only observed in the early morning or early evening (they basically rise and set with the sun). They are never seen on the opposite side of the earth from the sun. Venus and Mercury exhibit the full range of phases, like the moon, but the other planets do not. The reason for this is that Venus and Mercury have orbits closer to the Sun than the Earth (inferior orbits), the other planets have orbits farther away than the Earth (superior orbits).

Venus and Mercury both exhibit a full / gibbous phase when observed near the Sun, but farthest from the Earth. If they orbited the Earth (geocentric), we would never see a full phase when they are near the Sun. This proves that Venus and Mercury orbit the Sun, and not the Earth.

The problem with this, Michael, is that you are working with an incorrect model of the Geocentric system. In the Tychonic system, which we are using, all the planets orbit the sun, not the earth. It is the sun that orbits the earth, and carries the planets along with it. Thus, the diagram you showed which has Venus orbiting the earth is wrong, and that is why the model doesn't work for you.

As for the Geocentric explanation of the phases of Venus, it can be explained both from a Ptolemaic system and a Tychonic system.

First the Ptolemaic system.

Galileo had claimed that the Ptolemaic system could not account for the phases of Venus or Mercury. Actually, Galileo was partially correct. If one uses circular orbits for Venus and Mercury, the phases of the two planets do not appear. But if one uses elliptical orbits, as even Kepler did for the heliocentric system, then the phases of Venus and Mercury can be easily accounted for in the Ptolemaic system. Even the Jesuit astronomers who were challenging Galileo's findings knew this to be the case, and thus they submitted their evidence to the Inquisition, which also concluded that Galileo had no proof that only the heliocentric system worked. In fact, the only thing that Galileo's findings showed was that the epicycles in the Ptolemaic system were much larger than had previously been suspected.

As for the Tychonic model of Geocentrism, if one uses the same elliptical orbits of Kepler, the result is that two epicycles in the Ptolemaic system will translate into one ellipse, per planet, in the Tychonic system. Thus, around the sun, Mercury and Venus would each have a perigee and an apogee, and each locus of points along that polarity would show the respective phases of Mercury and Venus, as viewed from earth.

Thank you for your submission.

Robert Sungenis
Catholic Apologetics International
November 20, 2002

I presumed that Robert was defending a pure Geocentric system, in which all planets orbited a stationary Earth as proposed by Aristotle and Ptolemy. However my presumption was incorrect. As he states above, he is defending a system in which all planets but the Earth do orbit the Sun. Tycho Brahe proposed such a system. Here are links to pages that demonstrate the various systems.

Conduct another "experiment"

Again, at the following web site, run the simulation:

1. Enter 55P in the "Object Name" box.
2. Press "Search" button.
3. Press "Show Orbit" button.
4. Run the simulation as before, but in the "Center" drop down menu, select "Earth" rather that "Sun". Note that the Earth appears to remain stationary, and the Sun and all the other planets appear to revolve around the Earth.

Note you can toggle the "Center" menu to any planet, and you do not change any of the mechanics of the simulation, you only change the presentation of the graphic, and artificially center everything on the selected planet. This is basically a matter of perception. You can center everything on the Earth, or Mars, or Jupiter for that matter, and the whole universe is presented as revolving around the selected center, but nothing else changes (in particular, no epicycles are needed to introduce retrograde motion).

So I think this simulation shows rather effectively, whether the Earth is in the center, or the Sun is at the center, can be purely a matter of perception, and not physics. So it is quite possible for one person to perceive the Earth as orbiting the Sun, and someone else to perceive the whole universe as orbiting the Earth, and yet, hard as it may be to believe, both can be quite "right" at the same time, and neither can "prove" the other wrong, because everything else is absolutely identical for both of them.

Before you say that's just plain crazy, how does the Heliocentrist Christian explain this? -

Josh 10:13 And the sun stood still, and the moon stayed, until the people had avenged themselves upon their enemies. Is not this written in the book of Jasher? So the sun stood still in the midst of heaven, and hasted not to go down about a whole day.

The Heliocentrist Christian, who believes that the Earth spins on its axis once in 24 hours while at the same time orbiting the Sun, generally has no problem accepting this verse as absolutely true. The answer is easy. The Earth just stopped spinning on its axis for 24 hours, and in that way the Sun stood still for a whole day. How? Simple. God willed it, and it just happened. After all, nothing is impossible with God, right? Well thank you very much. If God could maintain the status quo, while at the same time stopping the Earth on its axis, is it just possible that THAT is really the norm, and it was really the universe that stopped its motion around the earth? Well, can you prove it didn't?

CAI on their index page advertises my discussion with Robert Sungenis as follows:

Responding to our $1,000 Geocentric Challenge, enthusiast Michael Scheifler entered with full guns blazing to kill off the Geocentric prevaricators. To his utter shock, using charts and graphs he had marshaled from NASA and other sites, Michael discovered just the opposite of his original contention. In the end, he confessed that he had no way to make a case against Geocentrism. Click above to see the "confession."

To set things straight, I set out to show that the prevailing geocentric view in the 15th century, accepted by the Catholic Church, that all the planets orbited the earth in perfect circles (Aristotle / Ptolemy), was rather easily consigned to the rubbish heap by something as simple as observing the phases of Venus through a telescope. But, as evident in the above discussion, Robert does not defend the pure geocentric systems of Aristotle and Ptolemy, but rather the modified system of Tyco Brahe, which in the strictest sense is anything but what the Catholic Church historically accepted as true. The Tychonic system concedes that the Earth rotates on its axis in 24 hours, and that all the planets but Earth orbit the Sun, without Ptolemaic epicycles. It is really all but conceding heliocentrism, turning it upside-down in a manner of speaking, by artificially setting the otherwise overwhelmingly heliocentric system in a last gasp minimalist geocentric context.

So my "original contention" stands, I have not been "shocked", nor have I taken an "opposite" view. I quite firmly believe that the heliocentric system IS reality, and that this does NOT contradict the Bible in any way. But at the same time, and from the very beginning, I fully recognized that if Robert so chooses, there is nothing that can persuade him that his Geocentric perception is wrong. If he so desires, he will always be able to adapt his view to include any contrary "proof", or explain it away to his satisfaction, and still maintain that his Earth-centered system "works". But at the same time, his facade of irrefutability, and strictly literal interpretation of the Bible on this topic, in no way insure that his geocentric view is reality.

Other discussions with CAI:

A Rebuttal to Jacob Michael of CAI on the Sabbath / Sunday Issue
A Response to Catholic Apologetics International's "Sacrifice Challenge"