When we gaze at the Sun, we see a lone star lighting up our Solar System.

Scientists now believe that our Sun may have once had a twin—an elusive companion lost to time!

A Lone Star in a Sea of Pairs

Many stars in the Milky Way exist in pairs, bound together by gravity in binary systems. Our nearest neighbors, Alpha Centauri A and B, are an example. Yet, our Sun travels solo through the galaxy. This is unusual, considering that recent studies suggest most stars begin their lives in pairs.

The Lost Companion Theory

Astronomers have long speculated about the possibility of a hidden solar sibling. Some even proposed the existence of a faint companion called Nemesis, which might have influenced the movement of objects in the outer reaches of our Solar System. However, multiple surveys have found no evidence of such a star lingering nearby. That means, if our Sun had a twin, it must have drifted far away—perhaps even to the other side of the galaxy.

Clues in the Oort Cloud

One of the strongest hints that our Sun once had a companion lies in the Oort Cloud—a vast region of icy objects surrounding the Solar System. Scientists believe that a binary star system could have helped shape this mysterious shell, capturing and scattering comets in a way that a single star could not. Some researchers also suggest that a missing twin might explain the presence of a yet-undiscovered planet, sometimes referred to as Planet Nine.

Did a Twin Tilt the Sun?

Another piece of evidence comes from the slight tilt of our Sun. Our Solar System's planets orbit in a relatively flat plane, but the Sun itself is tilted about seven degrees. Some astronomers propose that the gravitational pull of a long-lost twin might have caused this strange misalignment early in the Sun's life. If true, this could be another sign that our Sun was not always alone.

Will We Ever Find the Missing Twin?

If our Sun had a twin, could we ever find it? The problem is that our Sun was born in a crowded star cluster. Over billions of years, these sibling stars have spread across the Milky Way, making it nearly impossible to identify a single missing companion. Scientists have found stars with similar chemical compositions, but pinpointing the exact twin remains a daunting challenge.

What This Means for Other Worlds

The idea that our Sun may have once had a twin changes how we think about star systems. Many exoplanets orbit binary stars, some even experiencing twin sunsets like in science fiction. If our own Solar System started this way, it suggests that life can still thrive in such environments. While a second Sun might have disrupted Earth's orbit, we seem to have been lucky—our world found stability, allowing life to flourish.

The Search Continues

With powerful telescopes like the upcoming Vera Rubin Observatory, we may soon uncover more secrets about our Sun's past. If there is any lingering evidence of a lost twin, we might finally be able to trace its journey through the galaxy.

Until then, the mystery remains: did our Sun once have a twin, and if so, where is it now?

How Sun's Lost Twin Is Still Affecting The Solar System

Video by The Secrets of the Universe