Science Ch.30 - Predicting the Future by the Stars

Astronomers can predict heavenly signs foretold by the Bible, such as blood moons, and the wise men predicted Christ’s birth. Can we predict the future using the Bible or the stars?

Nowadays, an Old Testament prophet might well make it onto the nation’s wealthiest people list, because reliably predicting the price of corn or oil can net you a fortune trading in stock market futures. Elisha correctly predicted a fall in corn prices (2 Kgs 7:1), so in the business world of today he could have been a rich man. The book of Revelation has some similar commodity price predictions that immediately precede the occurrence of some “blood moons” (Rev 6:6, 12). Are you tempted to look up the astronomy charts to work out the timing?

       Horoscopes and star charts are still incredibly important in some Eastern cultures, as well as being popular (“just for fun”) in the West. Somehow we can’t get it out of our minds that our destiny is tied up with those lights that shimmer above us. In ancient days, when stars and planets were thought to be capricious gods, this did make some kind of sense. The surprising thing is that this belief continued even after Mesopotamian astronomers put together a huge dataset of observations and started accurately predicting heavenly events. Instead of deciding that the heavenly bodies clearly weren’t unpredictable divinities, they concluded that this information could be used to predict good and bad luck.

       For example, they expected a solar eclipse to bring extreme bad luck, especially for the ruler. So when the astronomers said that one was due, a substitute was put on the throne to rule just for that day, so that the expected bad fortune would fall on him rather than on the king. The next day they sacrificed the stand-in to ensure that the full bad luck of the eclipse fell on him. One fortunate individual, who happened to be a gardener, escaped being sacrificed because the real king died on that same day from drinking soup that was too hot – so the substitute carried on reigning.1

5-minute summary

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Star of Bethlehem

The magi – usually translated the “wise men” – came from Mesopotamia to see Jesus. Some people regard their use of the stars as a justification for using horoscopes – after all, they did appear to predict the future by looking at astronomical events. However, this idea doesn’t stand up to much scrutiny.

       There are two main theories concerning what they saw: either a comet or a conjunction of planets. Combining the two creates a compelling account. The planets Jupiter and Saturn were conjoined (that is, they were very close to each other) in the constellation of Pisces three times in 7 BC, and then again in 6 BC along with Mars. These were followed by a comet that was visible for seventy days in 5 BC according to ancient Chinese records. These events would be very significant for the magi, who believed conjunctions of Saturn and Jupiter portended important events, and associated Pisces particularly with the country of Israel.2

       At this point we have to ask whether the planets and stars actually influence life on earth (as astrologers claim) or whether God planned Jesus’ birth to come at a time that the magi (and a few others) would have regarded as significant. Johannes Kepler saw these same planetary conjunctions when they occurred again in 1604, and he calculated that this event occurs every 805 years. His own sighting was followed by the appearance of a supernova, which created a bright new star in the sky – the second-brightest supernova in history. And yet these celestial events in Kepler’s day didn’t accompany anything close to the importance of the birth of Christ. Kepler himself felt that something significant did happen every 805 years: Moses was born in 1617 BC, Isaiah in 812 BC, the reign of Charlemagne began in 799 AD, and the Reformation in 1604. Unfortunately, all these dates are wrong: the birth of Moses occurred three centuries later than Kepler “predicted” by the stars, Isaiah about one century earlier, the coronation of Charlemagne a year later, and the Reformation is generally dated from the time of Luther’s Ninety-Five Theses in 1517 or a host of other events, none of which occurred in 1604.

       Just because Jesus’ birth was timed to coincide with signs that some would regard as significant does not mean that they produced that birth or predicted it, because similar signs do not produce other equally significant events on other occasions. This doesn’t put off astrologers, because it is usually possible to find something that has occurred that could be tied to a celestial event. So throughout history, the stars have been studied to see whether they can reveal some secrets about the progress or future of the world.

Predicting astronomical events

The very first mechanical calculating device, the Antikythera mechanism, was invented to make astronomical predictions. This complex matrix of bronze cogs and dials included a special function for predicting red lunar eclipses. It was probably based on a design by Archimedes from the third century BC. In about 60 BC, it was lost in a shipwreck on the way to Rome and was recovered from the seabed in 1901 – though its purpose wasn’t known until X-ray tomography revealed its internal structure.3

       Like many inventions today, this kind of device had military applications. A terrible Greek naval disaster occurred in 413 BC at the time of a lunar eclipse, which encouraged the belief that military men could take advantage of heavenly portents. In 585 BC Greek mathematician Thales was able to warn the embattled Lydians that a solar eclipse was due. They could have used this for military advantage in a battle with their long-term enemies, the Medes, by preparing for the sudden darkness that they knew would occur – their unprepared enemy could have been easily defeated in the confusion. But instead it appears that they used it to engineer a lasting peace. When the expected darkness interrupted the fighting, they declared that the gods were demanding an end to the war.4

       Even as late as 1504, Columbus was able to use a similar trick to imply that God was on his side. He had been stranded in Jamaica for some time, and the islanders were fed up with having to feed his unruly men. Realizing that he had to gain the upper hand, he consulted his seaman’s almanac and discovered that there was going to be a red moon. He announced to the islanders that the moon would show God’s anger about their reluctance to feed his men anymore. When the earth’s shadow fell across the moon so that it turned blood-red, the islanders started wailing, begging forgiveness, and running to bring food.5

Blood moons

Few people today are bothered about blood moons – except for some Christians. This is because the Bible has a handful of predictions involving the moon turning to blood, some of which relate to Jesus’ second coming. Blood moons by themselves happen relatively frequently – about every two years on average. However, a few years ago something less common occurred: a lunar tetrad – that is, a group of four lunar eclipses separated by six-month intervals. This tetrad spanned from 2014 until the last one on September 28, 2015. In fact, this century is special because it contains eight such tetrads, from 2003/2004 until 2090/2091.

       Some preachers caused excitement by pointing out that the eclipses happening in 2014/2015 were all falling on Jewish festivals: the ones in April 2014 and 2015 on the first day of Passover, and the two in September on the first day of Tabernacles. This was considered so awesome that I was asked by a Christian magazine to predict what would happen in the light of Bible prophecy. Unfortunately, I had to disappoint readers by explaining that this precise pattern is relatively common because alignment with Jewish festivals occurs on one in six of these blood moon tetrads. The reason is that Passover and Tabernacles always occur at full moon and are always six lunar months apart, and blood moons also always occur at full moon, and when they occur in a tetrad they are always six months apart. In fact, it would be more significant if none of eight tetrads this century had lined up with these festivals. Perhaps the most significant thing about this particular tetrad is that all four were visible in the US, so a lot of American believers were aware of them.

       In the Bible, darkened or blood-red moons are generally mentioned along with overwhelming destruction from God: on Judah (Joel 2:10, 31), on Egypt (Ezek 32:7), on Babylon (Isa 13:10), and on “the kings on the earth” (Isa 24:21-23). Other verses that link a blood moon with the final “Day of the LORD” (Joel 2:10; 3:15, Isa 13:10) were cited by Jesus and Peter when describing the second coming (Matt 24:29 and parallels; Acts 2:20). In Jesus’ description, these final blood moons occur after “the tribulation of those days” and immediately before “the Son of man coming on the clouds” (Matt 24:29-30).

       Does this mean that astronomical predictions could help us determine likely windows of time when Jesus’ return will happen? Unfortunately (or perhaps fortunately), these biblical descriptions are likely to have nothing to do with actual astronomic phenomena. Phrases such as “the moon will turn to blood” were part of the shock-and-awe language of ancient divine warfare, along with the heavens being rolled up like a scroll and stars falling out of the sky (Isa 34:4; Matt 24:29; Rev 6:14). An equivalent modern threat would be, “We will flatten all your cities with mushroom clouds that darken the sun and turn the moon red.” Someone who isn’t used to our idioms would be confused to find that bombed cities aren’t actually flat and that no fungi are involved – it is just our language of destruction. In the same way, moons turned to blood are part of the Hebrew language of destruction.

How Bible prophecy works

I don’t believe that Bible prophecy is given to us as a method for predicting the future – it does foretell the future accurately, but its purpose is not to help people know future timing in advance. Rather, it is a means of giving comfort to those who will be going through those events, because they will be able to recognize their own days in retrospect and realize that God knew what would happen in advance. If someone had tried to use Psalm 22 to predict the trials of the Messiah, they would have assumed he’d have to face angry bulls and lions before being ravaged by dogs, perhaps in a Roman arena (read Ps 22:12-13, 16). But after the event, we can recognize which parts of this psalm are metaphorical and which ones are surprisingly literal. Who would have guessed that his sufferings involved specific literal injuries to his hands and feet or that the execution method involved hanging in the sun and becoming dehydrated (vv. 15-16)? Someone trying to use this psalm to predict the future would have gotten things hopelessly wrong, but after the event we can recognize that it foretold what would happen with amazing accuracy.

       The early church was able to take comfort in such prophecies after Jesus was killed. In fact, Jesus himself used prophecy in this kind of way: when talking on the road to Emmaus, “beginning with Moses and all the Prophets, he explained to them what was said in all the Scriptures concerning himself” (Luke 24:27).

       When the predicted disasters occur, we’ll be able to realize that God knew all about it and had a remedy planned, because we will recognize the prophecies. But we should only expect this to work in retrospect. Too many people have made fools of themselves by trying to predict from the Bible what will happen – and have ended up making the Bible look foolish to those who listened to them.

       Some preachers who thought that the blood moons of 2014/2015 were especially significant regarded Islamist terrorism as part of the “great tribulation, such as has not been from the beginning of the world until now, no, and never will be” – because this precedes the blood moons just before Jesus’ second coming (Matt 24:21 ESV). But, as usual, this turned out to be a false alarm.

       We humans are always on the lookout for danger, and this is a healthy and life-sustaining trait so long as we recognize it. Even without stars, moons, or horoscopes, we can find the potential for predicting disaster. When the year 2000 came along, there was a sophisticated version of millennial apprehension: the Y2K bug. The fear was that older computers weren’t programmed to understand years beyond 1999, so they might have gotten confused when that year ended. It was predicted that bank safes wouldn’t open, billing would go wrong, medical equipment would stop, planes would fall out of the sky, and intercontinental missiles would fire on their own. Christian leaders advised stocking up food, and Jerry Falwell even suggested buying a few guns, as he himself had done, to “persuade others not to mess with us.”6 I felt particularly sorry for Steve Hewitt, the editor of Christian Computing Magazine, who had enough specialist knowledge to know that this was hype. He was the voice of sanity when many well-known preachers were stoking this fear, but fellow Christians severely criticized him for ignoring the Bible message about coming disasters.7

       Many such “crises” have come and gone, and I’m sure that the next one will soon turn up. When we look up to the stars or stare into the future, we need to look to the Creator of those hosts, who has proclaimed that he is bringing about a good future. Yes, he has also given us warning of severe trouble on the way – not so that we can work out exactly what and when it will happen, but so that we won’t lose heart or faith when it does.


• The “star of Bethlehem” was probably an event that recurs every 805 years, but it was only significant once.
• Predicting eclipses and blood moons is interesting, but this cannot tell us about the future.
• Bible prophecies, like the ones predicting the Messiah, are accurate but can only be recognized in retrospect.
• Proposal: God provides predictions of troubles in the future so that those who will suffer them know that he is still in control – not so that we can foretell the future.

1^ See Sarah Graff, “The Solar Eclipse and the Substitute King,” Now at the Met (
2^ See Colin J. Humphreys, “The Star of Bethlehem, a Comet in 5 BC, and the Date of the Birth of Christ,” Quarterly Journal of the Royal Astronomical Society 32 (1991): 389-407 (
3^ See Wikipedia, “Antikythera Mechanism” (
4^ See Wikipedia, “Eclipse of Thales” ( Unsurprisingly, there are other theories. See Natasha Frost, “Was the First Eclipse Prediction an Act of Genius, a Brilliant Mistake, or Dumb Luck?,” Atlas Obscura (2017) (
5^ See Wikipedia, “March 1504 Lunar Eclipse” (
6^ See Rob Boston, “Apocalypse Now?,” Church and State (1999) (
7^ See Dave Hunt, “Y2K the Real Disaster,” The Berean Call, May 1, 1999 (

This was previously published in a similar form in Christianity magazine

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