Organic Material Older Than The Sun Found?

dr. what · Post by **dr. what** » 2006-12-04 09:07am

I, for one, welcome our ancient organic globule overlords...

Organic globules found in a meteorite that slammed into Canada's Tagish Lake may be older than our sun, a new study says.

The ancient materials could offer a glimpse into the solar system's planet-building past and may even provide clues to how life on Earth first arose.

"We don't really look at this research as telling us something about [the meteorite itself] as much as telling us something about the origins of the solar system," said Scott Messenger of the NASA Johnson Space Center in Houston, Texas.

Most of the meteorite's material is about the same age as our solar system—about 4.5 billion years—and was likely formed at the same time (tour a virtual solar system).

But the microscopic organic globules that make up about one-tenth of one percent of the object appear to be far older.

In a study appearing in tomorrow's issue of the journal Science, Messenger and colleagues report that isotopic anomalies in the globules suggest that they formed in very cold conditions—near absolute zero.

"What's really striking about this is that these globules clearly could not possibly have formed where [the meteorite] itself formed," Messenger said.

"Under those extreme conditions the air that you'd breathe would be solid ice. You would never find those conditions in the asteroid belt or anywhere close to the sun."

Cold Origins

The Tagish Lake meteorite flashed across Earth's northern sky in January 2000.

Most of the object burned up in the atmosphere, but pieces of it crashed in Canada's frozen, sparsely populated Yukon Territory and northern British Columbia (map of Canada).

"It's the lowest density meteorite that's ever been studied," said Peter Brown, a meteor expert and professor at the University of Western Ontario in Canada.

"It's extremely friable"—easily pulverized—"and the material breaks up very easily."

The object's fragile nature is one of the clues that led some scientists to theorize that Tagish Lake could be the most primitive meteorite ever discovered.

"By primitive we don't mean the oldest chronologically," explained Brown, who is not involved with the Science study.

"We mean that the material in the meteorite has been processed the least since it was formed. The material we see today is arguably the most representative of the material that first went into making up the solar system."

The meteorite likely formed in the outer reaches of the asteroid belt, but the organic material it contains probably had a far more distant origin.

The globules could have originated in the Kuiper Belt group of icy planetary remnants orbiting beyond Neptune. Or they could have been created even farther afield.

The globules appear to be similar to the kinds of icy grains found in molecular clouds—the vast, low-density regions where stars collapse and form and new solar systems are born.

Links to Life?

Some scientists speculate that organic matter arriving via ancient meteorites and comets are responsible for the rise of life on Earth.

(Related news: "Building Blocks of Life Found in Two Meteorites" [December 19, 2001].)

The unique shape of the newfound globules could be of particular interest to supporters of this theory.

The structures are invisible to the naked eye and resemble minute hollow balls with carbon-rich shells. A chunk of meteorite no larger than a grape could contain a billion of the tiny globules.

Theoretically, their hollow-ball shape could have presented a homey environment of concentrated organic matter where early cellular life could develop.

Such theories boast little evidence but raise many intriguing questions.

"We don't claim that these things are alive or anywhere close to being alive," NASA's Messenger cautioned.

"But the fact is that this material fell down on Earth, and similar if not identical material has been falling onto the Earth for its entire history.

"Understanding the origins of that matter is inherently tied in with understanding the origins of life."

Talanth · Post by **Talanth** » 2006-12-04 09:21am

I'm not sure I understand. They're talking about organic residue within the rock which is older than the rock which contains it? I asume it's deep within the rock or it would have been burnt away by the atmosphere, so how was it the rock could have formed around it? Unless it's the bacteriol equivelent of superman...

Rye · Post by **Rye** » 2006-12-04 09:29am

Talanth wrote:I'm not sure I understand. They're talking about organic residue within the rock which is older than the rock which contains it? I asume it's deep within the rock or it would have been burnt away by the atmosphere, so how was it the rock could have formed around it? Unless it's the bacteriol equivelent of superman...

Organic in this context means carbon based, not living.

Talanth · Post by **Talanth** » 2006-12-04 09:37am

True. I was asuming that anything organic is automaticly structuraly weaker than rock, forgeting the set of counterexamples in my mouth. So I guess it depends on how the rock was formed: from molten or from compacted dust.

GrandMasterTerwynn · Post by **GrandMasterTerwynn** » 2006-12-04 01:02pm

Talanth wrote:True. I was asuming that anything organic is automaticly structuraly weaker than rock, forgeting the set of counterexamples in my mouth. So I guess it depends on how the rock was formed: from molten or from compacted dust.

Yes. All large debris in the solar system forms through gravitational accretion of smaller bits of debris. For a given definition of large, the collisions aren't energetic enough to significantly alter the physical and chemical makeup of the final body. A lot of asteroids that whiz about in the solar system are so-called rubble piles, which came together in a relatively gentle fashion. One can expect a lot of 'primitive' materials from bodies like these.

A few others gained enough heat to partially melt and differentiate early on. Very few others gathered enough material that radioactive heating completely melted them, allowing for differentiation into a crust, mantle, and core.

nickolay1 · Post by **nickolay1** » 2006-12-04 01:46pm

Talanth wrote:True. I was asuming that anything organic is automaticly structuraly weaker than rock, forgeting the set of counterexamples in my mouth. So I guess it depends on how the rock was formed: from molten or from compacted dust.

Though formed by an "organic" process, the hydroxylapatite of which tooth enamel is composed of isn't actually organic itself.

Sikon · Post by **Sikon** » 2006-12-04 05:54pm

Organic material in terms of hydrocarbons is actually quite common on a number of extraterrestrial objects. The bulk of comets are well beyond the orbits of the planets, but even those within Jupiter's orbit have trillions of tons of kerogen, which is like oil shale. Dark comets are comprised of about an equal mixture of kerogen, silicates like clay, and water ice.

There are a lot of cometary objects with undifferentiated material, never melted or vaporized since the formation of the solar system about five billion years ago. The Oort Cloud and Kuiper Belt may have as many as perhaps a trillion cometary objects, perhaps a large portion of the total mass of the solar system outside the sun, though little is known.