Impacts with comets and asteroids were common during the Earth's youth

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Comets could have seeded life on Earth
By BBC News Online science editor Dr David Whitehouse

Thursday, 5 April, 2001, 15:08 GMT 16:08 UK

By simulating a high-velocity comet collision with the Earth, a team of scientists has shown that organic molecules hitch-hiking aboard a comet could have survived an impact and seeded life on Earth.

The results add weight to the theory that the raw materials for life came from space.

"Our results suggest that the notion of organic compounds coming from outer space can't be ruled out because of the severity of the impact event," said Jennifer Blank of the University of California, Berkeley.

Blank and her colleagues presented their findings at the national meeting of the American Chemical Society in San Diego.

New science

The researchers shot a can-sized bullet onto a coin-sized metal target containing a droplet of water mixed with amino acids, the building blocks of proteins.

To date more than seventy varieties of amino acids have been found in meteorites and some in interstellar dust and gas clouds.

It was observed that not only did a good fraction of the amino acids survive the collision, many had been polymerised into chains of two, three and four amino acids, so-called peptides, the first stage of building proteins.

What's more, freezing the target to mimic an icy comet actually increased the survival rate of the amino acids.

The test was designed to simulate the type of impact that would have been frequent during Earth's early history, some four billion years ago, when rocky, icy debris in our solar system accumulated to form planets.

During this violent time much of the debris would have resembled comets - dirty snowballs thought to be mostly slushy water surrounding a rocky core - slamming into Earth at velocities greater than 25 km per second (16 miles per second).

Oblique impact

The severity of the laboratory test was equivalent to an oblique collision with the rocky surface of the Earth, a comet coming in at an angle of less than 25 degrees from the horizon, rather than head on perpendicular to the Earth's surface.

"At very low angles, we think that some water ice from the comet would remain intact as a liquid puddle concentrated with organic molecules, ideal for the development of life," Blank said.

"This impact scenario provides the three ingredients believed necessary for life: liquid water, organic material and energy," she added.

Though it has been estimated that in Earth's early history only a few percent of comets or asteroids arrived at low enough angles, the bombardment would have been heavy enough to deliver a significant amount of intact organic material and water, according to Blank's estimates.

The next hitch-hikers she plans to subject to a shock test are bacterial spores, which some have proposed arrived on Earth via comets to jump-start evolution.

-- Uncle Bob (unclb0b@aol.com), April 05, 2001

Answers

It is just as possible that an alien space ship dropped off some of their people to populate the Earth. It is also possible that they dropped of a bunch of undesirables, just to get rid of them. That is why there is so much hostility among Earthlings, because we inherited those bad qualities. Who knows?????

-- pancake freddie (pancakefreddie@aol.com), April 06, 2001.

Well sure the concept is plausible, but completely unnecessary in order to believe that life on earth was seeded from outer space. Remember that the earth is itself hurling through outer space, and collects all sorts of debris along the way in the normal course of things because of its gravity. If there are microbes floating around in space, then you can be sure that earth has collected its share of them. That's why I could never understand why people are sometimes so concerned about the possibility of contamination of "alien" organisms. For that matter, what do you suppose the earth is composed of in the first place - debris from "outer space" of course. One credible theory I've also heard is that our oceans are formed from asteroid ice collected during previous impacts.

-- Ron

-- Ron (rkba@pacbell.net), April 06, 2001.

Another case of fantasy cloaking itself with the name 'Science.' What can we expect when such pseudo-scientific dogma as 'Evolution' has been accepted as dogma for the last 150 years, without a shred of hard, scientific evidence. Indeed, the sad convoluted explanations of the Goulds sound like the ingenious but flawed 'epicycle' explanations of the last of the Ptolemeans.

This is not an argument for Creationism. This is a time for Science to quit fooling around and behave itself. If they have to resort to such embarassing dei-ex-machina as comets being the greyhound bus to the galactic frontier, perhaps they should consider getting real jobs.

Wait, I know. There is somehow a bid for funds for research in this, just like the baloney about bacteria in meteorites a couple years ago. Science the handmaiden to the money trail, yep.

-- Scarecrow (SOmewhere@over.rainbow), April 06, 2001.

Darn, I had hoped all the wackos were over on TimeBomb2000. Oh well. By the way, it's "Deus ex machina" not "dei-ex-machina."

-- Ron (rkba@pacbell.net), April 06, 2001.

I'm unfamiliar with Ron, Scarecrow and Pancake. Welcome to Unk's. We've sent a flock of large birds to drop greetings on each of your cars/mopeds/bicycles (choose one or more). Our way here at Unk's of saying, "Hiya!"

I like what pancake stated - Who knows?. I sure as hell don't. That's why I listen to Art Bell; to get the skinny on Life, the Universe and Everything. [Tarz, the answer is 42]

I see no reason to get noses out of joint when we are all wildly speculating about this issue, Ron. Furthermore, I am most definitely a wacko, our numbers are far greater than can be accommodated on any one forum, and our formal association is, even as I write this post, organizing a protest march to begin and culminate in front of your house/apartment/corrugated box/plantation (choose one). So look out the window and wave. I'm the guy with the yeti-shaped birthmark on my forehead.

-- Rich (howe9@shentel.net), April 06, 2001.

Rich, I haven't heard "Hiya" in a long time, haven't said it in a long time either. It seems every time I greeted someone with that, the person thought I said, "how are you" and answered with a "good" or "not bad". I have since adopted the "hey" that my kids constantly say.

Back to the scheduled program. I agree with Ron's first post. Of course, it comes from space. Everything we have on mother earth came from space and the birth of our solar system as well as the "debris" in the cosmo. And further, I'm sure space trash contains compounds we've never even dreamed of.

-- Maria (anon@ymous.com), April 06, 2001.

Hiya, Maria! BTW, I regard Hiya to be a bastardized contraction of How are you. My last name should not be mistaken for Merriam-Webster, however.

My hypothesis as to origins of life is this: I think God shops at His local Southern States Farm Supply store, where he chooses seed packets to broadcast here and there whenever he gets the urge. I also believe He loses interest in His new plantings (as so many hobby gardeners do), which results in wild, uncultivated growth over time.

I'm thinking of writing a book which would delve further into this concept. I'm not just another pretty blonde with a vacant stare, ya know. I gots ideas.

-- Rich (howe9@shentel.net), April 06, 2001.

Rich Webster, yeah it fits ;)

Let me know when your book comes out. I'll be first in line for an autographed copy! How can anyone believe that inspiration doesn't come from God! Will the title be "the Word of God according to Rich"... or is it Bingo?

-- Maria (anon@ymous.com), April 06, 2001.

>>Oh By the way, it's "Deus ex machina" not "dei-ex-machina." -- Ron

No, Ron, my reference was to the plural form.

-- Scarecrow (SOmewhere@Over.Rainbow), April 06, 2001.

Couple questions my hypothesis brings to mind: Does God use hybridized seed, open-pollinated, or a bit of both? Is he a purist or does he genetically alter the seed after purchase?

-- Rich (howe9@shentel.net), April 06, 2001.

''The wisdom of man-is foolishness to GOD''=BIBLE yup it,s gonna get sillier & sillier-as mankind seeks to play GOD!!-------denying GOD they became worshippers of the creature- instead of the CREATOR!! BUT oh will the reaping be a bummer. the=pride of man-will be his downfall!!! but ,hey it's all been=prophesied-''as in the day's of noah'' the cup is almost full-time for the=cure!!!!

-- al-d (dogs@zianet.com), April 06, 2001.