During planet Earth’s earliest years, while our world was still forming, ice comets were essential sources of carbon that may have triggered life, a new study claims.
Astronomers at the University of Minnesota used infrared observations of Comet Catalina when it ventured into the inner solar system in 2016 to better understand the makeup of these icy visitors and their role in the development of planet Earth.
The team was able to detect significant amounts of carbon – a chemical essential to life as we know it – in the comet’s tail.
The rocky planets were probably too hot in their earliest days to capture enough carbon for life to begin, so they had to get the building blocks of life from somewhere.
“Carbon-rich comets could have been an important source providing this vital element that led to life as we know it,” says study author Charles Woodward.
This illustration of a comet from the Oort Cloud as it traverses the inner solar system with dust and gas evaporating in its tail shows how these icy visitors delivered carbon to hot, early rocky worlds like Earth.
The carbon-rich Comet Catalina was first discovered in 2013 during its last and maiden voyage through the inner Solar System
In early 2016, Comet Catalina entered the inner Solar System from the Oort Cloud, an area at the edge of the Solar System where comets are born.
It briefly became visible to stargazers on Earth before swinging by the sun to disappear forever out of the solar system and into interstellar space.
One of the many observatories that captured a view of this comet that appeared near the Big Dipper was the Stratospheric Observatory for Infrared Astronomy (SOFIA), NASA’s telescope in an airplane.
Using one of its unique infrared instruments, SOFIA was able to identify a familiar fingerprint in the dusty glow of the comet’s tail: carbon.
This discovery helps planetary scientists to explain more about the origins of life on Earth, as they “ become apparent comets like Catalina that could be an essential source of carbon ” during the early formation of the solar system, the team explained.
Using new results from SOFIA, a joint project between NASA and the German Aerospace Center, the US team was able to better understand the impact of these comets billions of years ago when planets such as Earth and Mars first emerged. started to form.
Comet Catalina and others of its kind are so long orbits that they arrive relatively unchanged at our celestial threshold.
This effectively makes them frozen in time – with much the same matter found in the earliest days of the solar system when planets first began to form into the world they are today.
This ‘time capsule’ offers researchers rare opportunities to learn more about the early solar system from which they originated and how our own planet may have formed.
NASA was able to observe the icy visitor using infrared cameras, which allowed astronomers to get a clearer picture of its composition – by finding a carbon-rich tail
SOFIA’s infrared observations were able to record the composition of the dust and gas as it evaporated from the comet and formed its tail.
The observations showed that Comet Catalina is carbon-rich, suggesting that it formed in the outer reaches of the original solar system, which contained a reservoir of carbon that could have been important for seeding life on Earth, Mars and Venus.
While carbon is an important ingredient of life, it cannot survive over time in a very hot world.
The early Earth and other terrestrial planets of the inner solar system were so hot during their formation that elements such as carbon were lost or depleted.
Infrared observations of the comet helped researchers see that it was rich in carbon, allowing them to theorize that these comets helped seed the hot, rocky early Earth.
Comet Catalina was visible through small telescopes or binoculars on January 1, 2016 as it closest approached Earth on its way to interstellar space
While the cooler gas giants such as Jupiter and Neptune could support carbon in the outer solar system, Jupiter’s jumbo size may have gravity-blocked carbon to mix back into the inner solar system.
This prompted the US team to investigate how the inner rocky planets evolved into the carbon-rich worlds they are today, by examining the comet’s data.
Researchers believe that a small change in Jupiter’s orbit allowed tiny, early precursors to comets to mix carbon from the outer regions to the inner regions, where it was incorporated into planets such as Earth and Mars.
The comets came from the outer edges of the solar system, were rich in carbon, pulled from their broad orbit by Jupiter’s tremendous gravitational pull, and pushed closer to the sun in the inner rocky worlds.
The carbon-rich composition of Comet Catalina helps explain how planets that formed in the hot, low-carbon regions of the early solar system evolved into planets with the life-sustaining element, the study authors said.
“All terrestrial worlds are subject to impacts from comets and other small bodies containing carbon and other elements,” added Woodward.
“We’re getting closer to understanding how these effects on early planets may have catalyzed life.”
Observations of additional new comets are needed to know if there are many other carbon-rich comets in the Oort Cloud, which would further support that comets provided carbon and other life-sustaining elements to the terrestrial planets.
As the world’s largest airborne observatory, SOFIA’s mobility allows it to quickly observe newly discovered comets as they sail through the solar system.
The findings of this study are published in the Planetary Science Journal.