Among the many observatories that photographed the comet Catalina in 2016, which appeared near the Big Dipper, was the Stratospheric Observatory for Infrared Astronomy (SOFIA). Using one of their unique infrared instruments, the researchers were able to detect familiar footprints in the dusty reflection of the comet’s tail – namely, the presence of carbon.
In early 2016, an ice comet from the edge of our solar system flew past Earth. For a short time, she became visible to observers and she was named Catalina, then flew past the Sun and disappeared forever from the solar system.
This event helped explain our own origins as it becomes apparent that comets like Catalina could have been an important source of carbon on planets like Earth and Mars during the early formation of the solar system.
“Carbon is the key to studying the origin of life. We’re still not sure if the Earth could have trapped enough carbon on its own during its formation, so carbon-rich comets could be an important source of this important element that gave rise to life as we know it.”
Charles Woodward, astrophysicist and professor at the Institute of Astrophysics, University of Minnesota
Originating from the Oort Cloud in the farthest corners of our solar system, comet Catalina and other comets of this type have such long orbits that they arrive in our system in a relatively unchanged form. This makes them appear to be frozen in time, offering researchers a rare opportunity to learn about the early system from which they came.
SOFIA’s infrared observations recorded the composition of dust and gas as it evaporated from the comet, forming its tail. Observations have shown that Comet Catalina is rich in carbon, suggesting that it formed in the outer regions of the original system, which contained a reservoir of carbon that may have been important for the origin of life.
Although carbon is a key ingredient in life, the early Earth and other terrestrial planets were so hot during their formation that elements such as carbon were lost or depleted. While cooler gas giants such as Jupiter and Neptune may have sustained carbon in the outer solar system, for example, Jupiter’s gigantic size could gravitationally block carbon mixing in the inner solar system.
The researchers believe that the slight change in Jupiter’s orbit allowed small early cometary precursors to mix carbon from the outer regions into the inner regions, where it was incorporated into planets such as Earth and Mars.
Comet Catalina’s carbon-rich composition helps explain how planets that formed in the hot, carbon-poor regions of the early solar system turned into planets with a life-sustaining element.
Observations of additional new comets are needed to see if there are many other carbon-rich comets in the Oort Cloud, further confirming that comets are delivering carbon and other life-supporting elements to terrestrial planets. The mobility of SOFIA, the world’s largest aerial observatory, allows the observation of newly discovered comets as they pass through the solar system.