Spitzer Telescope Spots Echo of Violent Early Solar System Activity

October 20th, 2011

Violent comet activity, like that depicted in this NASA illustration, marked an early era in our solar system and perhaps in other planetary systems. Water from comet impacts may have filled the Earth's oceans, delivered the building blocks for life.

 NASA’s Spitzer space telescope has unveiled what may be a “nearby” replay of the same violent processes that unfolded in our own solar system billions of years ago.

Imagery from the infrared observatory has spotted a stream of comets raining down on an alien planetary system, according to a NASA announcement.

That same process, known as the Late Heavy Bombardment, was responsible for bringing water to the Earth’s oceans and perhaps the complex pre-biotic chemistry that spawned life, scientists  believe.

During this period — around four billion years ago — comets and other icy objects that were flung from the outer solar system pummeled the solar system’s inner planets. Evidence for the barrage can be seen in the cratered surface of the Earth’s moon.

Spitzer, a sibling of the more famous Hubble Space Telescope, spotted evidence of a similar bombardment around Eta Corvi, a bright star visible in the northern sky.  Dusty impact fragments are located close to Eta Corvi — in a region where Earth-like worlds may exist. The scene suggests a collision took place between a planet and one or more comets.

The Eta Corvi system is approximately one billion years old, which researchers think is about the right age for a young planetary system to undergo such a hail storm.

“We believe we have direct evidence for an ongoing Late Heavy Bombardment in the nearby star system Eta Corvi, occurring about the same time as in our solar system,” said Carey Lisse, a senior research scientist at the Johns Hopkins University Applied Physics Laboratory, according to a NASA announcement.

Lisse is the lead author of a paper detailing the findings that is scheduled for publication in the Astrophysical Journal.

Spitzer’s infrared detectors examined the light emitted from the dust around Eta Corvi. The detectors revealed the chemical fingerprints for water ice, rock and carbon-based chemical structures that suggest a giant comet was the source.

A second, more massive ring of colder dust located at the far edge of the Eta Corvi system seems like the proper environment for a reservoir of comet like bodies, according to Lisse’s science team.

This bright ring, discovered a  half-dozen years ago, resembles a similar region in our solar system known as the Kuiper Belt. The Kuiper Belt is swirling with the icy, rocky leftovers from planet formation.

Spitzer, launched in 2003 was the last of NASA’s four Great Observatories. The observatory is in an Earth trailing orbit that circles the sun. The telescope has exceeded a hoped for life time of five years.



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