Zodiac signs may be out of date as Earth's wobble shifts the sky

Astronomers say the traditional zodiac used by tropical astrology no longer matches the sky as it appears today, because Earth’s axis slowly wobbles over time. The result, experts say, is that the signs most people associate with their birthdays may no longer align with the Sun’s position in the constellations as seen now. The phenomenon, known as axial precession, completes a 26,000-year cycle and gradually shifts the backdrop of the stars behind the Sun throughout the year.

The idea is well known in astronomy circles but has generated renewed attention after recent media coverage. Researchers note that while the Bell was set by Babylonian scholars more than two millennia ago, the celestial scaffolding has since moved. “If you take the idea seriously that star positions and the position of the Sun in relation to them actually influence people and their lives, then everyone's been told the wrong star sign for centuries,” said Dr. Mark Thompson, an astronomer, science broadcaster and author.

Two other factors amplify the debate around the traditional zodiac. First, the constellations themselves are not equal in size; the Sun spends varying lengths of time in each—from roughly a week in Scorpius to several weeks in Virgo. The practical consequence, according to planetary scientist Dr. Sheila Kanani, is that the ancient practice of slicing the sky into 12 equal segments was a convenience, not a reflection of the actual star patterns. “The Sun spends weeks drifting through sprawling Virgo, but barely a week in tiny Scorpius,” Kanani notes, underscoring that the 12-sign calendar was a simplification.

A second factor is the presence of Ophiuchus, the 13th constellation. It is not a new discovery, but it is rarely, if ever, included in traditional horoscopes. The Sun spends about 18 days each year moving through Ophiuchus, yet most astrology books keep to 12 signs. Some modern astrologers have argued for including it, but others prefer to preserve the 12-sign scheme, effectively leaving Ophiuchus out. When born between November 30 and December 17, some theories propose you could be Ophiuchian rather than Sagittarian or Scorpio, though that view is far from universal. Kanani says, “If we updated the zodiac, I would actually shift from being Sagittarian to being Ophiuchian.”

Relief or confusion aside, the scientific consensus remains that the zodiac signs do not dictate personality or life outcomes. Studies across years have failed to show a robust link between birth dates and personal traits or life events, and some scientists emphasize that the physics behind zodiac symbolism is weak. Thompson adds that even if star positions matter philosophically to some, the gravitational influence of the observer’s surroundings and circumstances would dwarf any subtle astronomical effect. “The physics of it? The gravitational pull from the doctor or nurse delivering you has more influence than Jupiter does,” he says, underscoring the gap between astrology’s claims and measurable science.

The debate also centers on how astrologers defend tropical astrology, the system most widely used in modern horoscopes. Proponents argue that tropical astrology is anchored to Earth’s seasons rather than to the current positions of the constellations, making the signs stable despite shifts in the sky. “Modern tropical astrology is not based on the stars but the seasons,” said Aliza Kelly, an astrologer known for working with celebrity clients. “It’s geocentric, meaning it’s anchored by our perspective on Earth, not the actual position of constellations.”

Astronomers and astrologers alike acknowledge the long history of the zodiac. The Babylonians laid the groundwork more than 2,000 years ago, and by the time Ptolemy, Kepler and Galileo mapped the heavens, astrology and astronomy were still intertwined. But the relationship between the two disciplines diverged during the Scientific Revolution, and by the 1800s the sciences had largely separated. Today, most scientists view the star-sign framework as a cultural artifact rather than a predictive science.

In recent weeks, reports—such as a Daily Mail Femail piece that highlighted the out-of-date zodiac and the updated calendar—have drawn attention to the dialogue between astronomy and astrology. Coverage in other outlets, including discussions prompted by The New York Times, has amplified the conversation among the public, with astrologers pushing back against what they view as a debunking of a tradition many follow for cultural or personal reasons rather than scientific reasons. The public reaction on social media has been swift and polarized, reflecting a broader divide between scientific literacy and belief in horoscopic guidance.

For scientists, the message is straightforward: the sky is dynamic, and the calendar used to map it—whether for navigation, science or popular culture—must adapt to reality. The shifts documented in axial precession mean that, for most people, the sign assigned to their birthday according to ancient traditions would be off by one sign when viewed through an astronomical lens. Yet the practical impact on daily life remains limited for most people, who engage with horoscopes for entertainment, self-reflection, or cultural reasons rather than as a source of empirical guidance.

As the dialogue continues, the core message from scientists remains consistent: while the heavens are a well of wonder, they do not neatly determine individual fates. The zodiac, in its current popular form, reflects centuries of cultural practice rather than a precise astronomical map. For readers seeking a precise alignment with the sky, experts suggest consulting updated star charts and considering the difference between the tropical (season-based) zodiac used in most horoscopes and the actual sky (sidereal) positions that astronomy tracks. In the end, the shifting sky serves as a reminder that science revises its understanding in light of new evidence, while tradition often travels a different path.