For several months, an ancient voyager unlike any other before has been visiting our small patch of the universe. In calling our visitor ancient, we mischaracterize its age as that word implies something several thousand years old, while this traveler’s lifespan is measured in billions of years.
On July 1, the NASA-funded Asteroid Terrestrial-impact Last Alert System, or ATLAS, telescope in Chile spotted this mysterious, celestial wayfarer, which has been named 3I/ATLAS.
It was a comet — and no ordinary one. Rarely would a comet have such a steep orbit and high speed as this one, at times traveling 153,000 miles an hour.
It was soon deduced that this is an interstellar comet, meaning it has come from another solar system. It’s only the third interstellar object ever confirmed — hence the “3” and “I” in its name, along with “ATLAS” for the telescope used to discover it.
While speculation about what the strange object was, including an alien spacecraft, ran rampant for months, the government shutdown prevented NASA from commenting on it or releasing images of it. Fortunately for the curious, the agency has now released images tracking the comet, which were taken by at least 20 spacecraft and ground telescopes.
Because 3I/ATLAS was first seen as it entered our solar system, scientists will have several months to study it during its sojourn, offering a rare opportunity to learn about its origins and how its composition differs from that of comets within our solar system.
Comets are time travelers from our past, carrying with them that from which we emerged. Composed of dust, ice, frozen gases and stories of our origins, they’re remnants from the genesis of our solar system 4.6 billion years ago.
No comet that has passed our way before has more stories to tell and secrets to share than 3I/ATLAS, which is estimated to be at least 7 billion years old and believed to be the oldest comet humans have ever seen.
Beyond yielding information about our origins, 3l/ATLAS could help us learn the origin stories and structures of other planetary systems.
Since the dawn of humankind, comets — streaking across the sky with their luminous heads and long fiery tails — have fascinated and frightened. For millenniums, they were seen as omens of tragedy or heralds of great events. Today, with human progress and the miracles of science, comets are no longer objects of fear but of continuing education.
3l/ATLAS is no threat to Earth. Although its size is substantial, with the diameter of its nucleus estimated at 444 feet to 3.5 miles, the closest it will come to us is about 170 million miles.
It will remain observable until the spring, and though it’s not visible with the naked eye, a small telescope will bring it into view.
While people, with few exceptions, no longer look to the sky in fear, we have never ceased looking to the stars in awe, even as we propel manned and unmanned spacecraft toward them, attempting to stretch deeper into the vast darkness of space.
3l/ATLAS is a reminder of the unfathomable wonders of space, how little we know about it, and how small and young our planet and species are. It traveled billions and billions of years before gracing our galaxy with its presence.
It’s unlike anything we’ve seen before, and given that there are 150 billion to 300 billion galaxies in the observable universe alone, it’s certain that we will witness more phenomena unlike anything we’ve seen before.
The mysterious marvel of the universe all but guarantees that more strange and unexpected visitors will be passing our way.
