NASA says a space telescope spotted what are likely strong carbon dioxide emissions from a comet that will pass through the inner solar system this year.

Images captured by the Spitzer space telescope suggest carbon dioxide is slowly and steadily "fizzing" away from the so-called "soda-pop comet," known as ISON, along with dust in a tail about 186,400 miles long, NASA's Jet Propulsion Laboratory in Pasadena, Calif., reported Tuesday.

Like all comets, ISON is a dirty snowball made up of dust and frozen gases such as water, ammonia, methane and carbon dioxide.

Warming up gradually as it approaches the sun, different gases are heating up to the point of evaporation, NASA scientists said.

"We estimate ISON is emitting about 2.2 million pounds of what is most likely carbon dioxide gas and about 120 million pounds of dust every day," said Carey Lisse, NASA's Comet ISON observation campaign leader at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md.

Comet ISON was about 312 million miles from the sun, 3.35 times farther than Earth, when the observations were made, scientists said.

"These fabulous observations of ISON are unique and set the stage for more observations and discoveries to follow as part of a comprehensive NASA campaign to observe the comet," James L. Green, NASA's director of planetary science in Washington, said.

Data collected from ISON may help explain how and when the solar system first formed, scientists said.

"This observation gives us a good picture of part of the composition of ISON, and, by extension, of the proto-planetary disk from which the planets were formed," Lisse said.