Ancient Interstellar Comet Could Be Older Than Many Stars
“It’s like glimpsing a rifle bullet for a thousandth of a second,” explained David Jewitt. It’s a very short amount of time, but it’s enough to change what we thought we knew. Already moving out of reach, the comet is one object we can’t catch. Data collected in its passage, however, promises to unlock deeper mysteries, including the object’s true age. Not just another comet passing through the area, but one from a much older era, leftover from the formation of the planets in the galaxy.
In an instant, 3I/ATLAS appeared, unlike most other objects passing through the region of space. According to NASA, only two others like it have been spotted in the area in all the years scientists have been tracking the cosmos. Right from the start, the object’s path gave it away – it was going too fast, too sharply, and in no other direction but one: out of the sun’s grasp. The speed and direction of the comet’s path indicated the Sun never held onto the comet, said NASA. This wasn’t an ice ball from the solar system, perturbed from its normal path. Instead, the object formed near another star, flung out eons ago.
What sets the object apart in the scientific world is the age it may possess. The speed of the object through space once suggested many possible ages, since objects moving quickly through the expanse tend to be deflected in many different ways by close passes to other stars in the area. More recent data, however, has narrowed those possibilities down to the very oldest ages possible. With the James Webb Space Telescope, scientists are using the instruments to study the chemical composition of the gases streaming from the comet, particularly the ratio of carbon-12 to carbon-13, as well as the amount of heavy hydrogen in the ice.
However, a clock awaits discovery among these features. As stars age and explode throughout time, they disperse carbon 13 into the universe, and therefore, its lower levels indicate a long, untouched past. On the other hand, 3I/ATLAS has extra deuterium in its ice, and this implies a birth in a deep freeze environment. Therefore, scientists believe 3I/ATLAS formed when our Milky Way was young and had not yet filled with heavy elements. This event may have occurred between 7.6 and 14 billion years ago, although isotopic evidence indicates 3I/ATLAS formed 10 or 12 billion years ago, a time close to when our galaxy formed its thick disk, a period much older than our sun.
Locating its star of origin? Sorry, not right now! Scientists do not have this ability. As 3I/ATLAS continues its journey through space, star encounters gradually erase its path through our universe. However, its chemical composition gives a hint about its original location and time of origin. As Martin Cordiner describes, “We believe that cometary materials in general are representative of the building blocks of planets outside the water snow-line in the protoplanetary disk.” If 3I/ATLAS follows this pattern, then do not think of 3I/ATLAS as just another ancient and icy wanderer, but a window into a past time when planet formation occurred long ago, far away in our universe.
As a result of this, what it is made of is just as important as how old it is. According to scientists, it has a lot of water and carbon, more than what we find in most of the comets we are familiar with. This suggests the presence of complex molecules and icy materials in the early days of the formation of planets. From the data provided by NASA, we can see it is not close enough to hurt the Earth and can therefore be observed with no cause for worry: it floats like a record.
What is most important may become clear only later, however. More objects from outside the solar system will likely be discovered once the new telescope, the Vera C. Rubin Observatory, begins operating. As a result, each new object provides another clue to whether 3I/ATLAS is an exceptional object or merely the first of an old group to be detected so early in the galaxy’s history. Right now, the fleeting visitor has provided planetary scientists with an unusual kind of evidence: evidence of the early existence in the galaxy of the raw materials for building planets.
