|
Study: Life on Earth May Have Been Seeded by Ancient Meteorites (pg. 2)
|
View this Thread in Original format
| Renegade |
| quote: | Originally posted by Magnetonium
Meteorites dont just crash into Earth and pour out zillions of cubic litres of water and Halleluyah. |
Meteorites don't, but comets do. There's a bit of contention about how much of the water on Earth originates from comets, but we know at least some of it (probably a lot of it) does. And we've known for quite sometime that complex organic molcules (like amino acids - the monomers that bind together to form the long proteins that every life form on Earth is composed of) exist in comets. This is just the first time, so far as I know, that these sort of molecules have been proven to exist in waterless meteorites.
| quote: | | That sounds stupid. It would make more sense if Earth was a one large "meteorite" at first. |
In a way it is / was. The Earth is composed of the same basic elements that meteorites are, the only major difference is size.
| quote: | | Besides, where does the water on the meteorites come from? |
Like Fledz said, this isn't about water. In fact, water - which would have covered basically the entire planet at around the time that life formed - actually inhibits many of the chemical processes involved in the creation of the organic compounds that life is founded on. This is why evidence of these compounds existing in abundance elsewhere in the solar system is so important, because it means that the first step isn't quite so insurmountable as it may have first seemed.
| quote: | | Or maybe I am just missing a point somewhere. I need someone to explain this development a bit more.[/COLOR] |
The point is that this discovery lends more support to the idea that the chemical compounds essential to all life may have formed much more easily and abundantly further out in the solar system (beyond the so-called "frost-line") and meteorites and comets therefore represent the most likely origin for these chemicals on Earth. |
|
|
| pkcRAISTLIN |
| quote: | Originally posted by Renegade
This is why evidence of these compounds existing in abundance elsewhere in the solar system is so important, because it means that the first step isn't quite so insurmountable as it may have first seemed. |
in terms of things being less insurmountable, how does the probability of a comet hitting a planet the right distance away from a star factor into it? |
|
|
| Renegade |
| quote: | Originally posted by pkcRAISTLIN
in terms of things being less insurmountable, how does the probability of a comet hitting a planet the right distance away from a star factor into it? |
Well, every major body in the solar system was battered by comets and meteorites for about 300 million years during the "late heavy bombardment period" (the Earth had 22,000 impacts with bodies 20km and greater in size during this time, according to that article) so the probability of any planet being struck by thousands upon thousands of comets during its history - regardless of its size or position relative to the sun - was basically 100%. |
|
|
| pkcRAISTLIN |
| quote: | Originally posted by Renegade
Well, every major body in the solar system was battered by comets and meteorites for about 300 million years during the "late heavy bombardment period" (the Earth had 22,000 impacts with bodies 20km and greater in size during this time, according to that article) so the probability of any planet being struck by thousands upon thousands of comets during its history - regardless of its size or position relative to the sun - was basically 100%. |
well, can't really argue with that then! :D |
|
|
| Magnetonium |
Thanks ... the only question remaining is - where the heck did this massive amount of water on Earth cam about from? What possible processes / chain of events? From lava to water planet ... thats quite the jump.
22000 meteorites doesnt cut it for me in terms of the amount of water that Earth ended up with.
What about the comets/meteorites themselves, where did their water / life building blocks come from? |
|
|
| LazFX |
Speaking of Water.....
I find this pretty focking cool!!
| quote: | The Mars Lander just found ice
There is water ice on Mars within reach of the Mars Phoenix Lander, NASA scientists announced Thursday.
Photographic evidence settles the debate over the nature of the white material seen in photographs sent back by the craft. As seen in lower left of this image, chunks of the ice sublimed (changed directly from solid to gas) over the course of four days, after the lander's digging exposed them.
"It must be ice," said the Phoenix Lander's lead investigator, Peter Smith. "These little clumps completely disappearing over the course of a few days, that is perfect evidence that it's ice."
The confirmation that water ice exists in the area directly surrounding the lander is big and good news for the Martian mission. NASA's stated goal for the Mars Phoenix was to find exactly this -- water ice -- and then analyze it. With the latest news, the first step is accomplished. All that's left now is to get the water into the Phoenix's instruments, a task which has occasionally proven more difficult than anticipated.
Still, this is the best opportunity that humanity has ever had to analyze extraterrestrial water in any form. That had the Phoenix Lander's persona fired up.
"Are you ready to celebrate? Well, get ready: We have ICE!!!!! Yes, ICE, *WATER ICE* on Mars! w00t!!! Best day ever!!" the Mars Phoenix Lander tweeted at about 5:15 pm.
Their suspicions about water ice beneath the surface of Mars confirmed, scientists and the world will have renewed interest in the outcome of the soil analyses currently being conducted by the lander.
The samples are being examined for traces of organic molecules, among other substances, but the lander does not have instruments that could directly detect life.
|
http://blog.wired.com/wiredscience/...phoenix-tw.html |
|
|
| Renegade |
| quote: | Originally posted by Magnetonium
Thanks ... the only question remaining is - where the heck did this massive amount of water on Earth cam about from? What possible processes / chain of events? From lava to water planet ... thats quite the jump.
22000 meteorites doesnt cut it for me in terms of the amount of water that Earth ended up with. |
No-one's entirely sure, but it stands to reason that at least some of the water on this planet was delivered by comets and meteorites (where else would the water go when the comet struck here?). Whether or not all the water came here that way is another matter, though, and many scientists disagree on this point. Here's just one of the competing theories:
http://space.newscientist.com/artic...t-in-space.html
| quote: | | What about the comets/meteorites themselves, where did their water / life building blocks come from?[/COLOR] |
Most of the lighter compounds (including water) were pushed by the solar winds in the early solar system from its center out towards its boundaries. This is why all the inner planets are small and rocky (these are the few elements that weren't scattered from the inner solar-system by the sun) and the outer planets are large and gaseous. Whatever water existed in the early solar system was scattered by the sun to the outer extent its influence (up to 1 light year), and ended up either absorbed into the bigger planets (along with large quantities of other light compounds) or in the Kuiper Belt and the Oort Cloud, where most of the comets in the solar system are. |
|
|
| Magnetonium |
I am not religious, but I gotta say that its impossible that the water we have on our planet was delivered by some comets/meteorites. No brainer. Yes, it does make sense how the solar system formed and how some substances were "blown" out of the inner solar system, ... thanks for explaining these and other points, Renegade. A lot of it makes sense except maybe for the how the large amounts of water came to be on Earth.
On the commentary side of things,
In my view, Earth's water was formed when the massive amounts of acids and bases just merged under certain conditions to form what was to come of the water. With the help of lighning, time and whatever other scientific factors, water-like substance was formed. Primitive life/microogranisms slowly turned that mush into more life-sustaining form. Sounds bizarre?
Heck, even in the life-lush dinosaur era the air would have been too toxic for humans to breathe, like seriously, 35% oxygen content is poisonous by today's standards. Or something like that. Life evolved.
EDIT: BTW, Renegade, I really enjoy reading your posts on religion so if you can recommend some books / articles on where you got the information / inspiration, let me know ;-) |
|
|
| DJ Shibby |
| Either way, life on earth is basically an extension of the planet. |
|
|
| Renegade |
| quote: | Originally posted by Magnetonium
On the commentary side of things,
In my view, Earth's water was formed when the massive amounts of acids and bases just merged under certain conditions to form what was to come of the water. With the help of lighning, time and whatever other scientific factors, water-like substance was formed. Primitive life/microogranisms slowly turned that mush into more life-sustaining form. Sounds bizarre? |
I think you're still confusing water with life. Water is an extremely simple, extremely common compound. The question about why the Earth has so much water is a good one, but explaining the existence of water itself in the solar system really isn't an issue: throw enough hydrogen and oxygen atoms together at the right temperature and the emergence of large quantities of water is basically inevitable.
| quote: | | EDIT: BTW, Renegade, I really enjoy reading your posts on religion so if you can recommend some books / articles on where you got the information / inspiration, let me know ;-) |
On the subject we're talking about right now, I recently read this book which is a good introduction to the sort of things we're talking about (how complex the chemical foundations of life are and under what conditions they might have formed). I've also got this book in my current amazon cart which I assume will address similar issues, but obviously I'm not sure how relevent or good it is just yet (reviews are promising though). |
|
|
| adi_hanson |
funny enough just watching a doc on the good old national geographic channel
writing points while viewing
points are:-
water from comets ,water/methanol/ammonia/organic compound filled dirty snowballs not meterorites
22000 is hard to belive but what if they were all 5 miles wide and being snowballs they melt
comets sprinkle earth with there contents, not crash into it
probe sent into comet discovers the elements mentioned above
they move onto stromatolites , bacterial colonys that live on the shore and show living ones today
mentions 1.5 billion speices of bacteria ut only 1% discovered
I notice that they always have circle a person 12 times with a camera before they say who they are
She is a major geek but takes us to boiling mud pits in bolivia and tells of bacteria that live there
Showing link with UV levels and expose naked DNA ,and results in it being destroyed then discover pigments that protect and results that UV could be the factor in kick starting life
Electic storms tested and experiment shows water with an atmosphere of methane hygrogen and nitrogen subjected to electric shocks overnight which fill the water with new amino acids and change its colour
shows the underwater vents ,proving sunlight isnt needed
shows experiments creating organic materials and report on a distinctive smell and more importantly molecular cell structures
metabolisim , most important chemical reaction in life
scientist to start life from scratch in big experiment
overview seems to point at comets , not meteorites , seeded the earth and volcanic,electric and UV played a major part |
|
|
| Magnetonium |
| quote: | Originally posted by adi_hanson
funny enough just watching a doc on the good old national geographic channel
writing points while viewing
points are:-
water from comets ,water/methanol/ammonia/organic compound filled dirty snowballs not meterorites
22000 is hard to belive but what if they were all 5 miles wide and being snowballs they melt
comets sprinkle earth with there contents, not crash into it
probe sent into comet discovers the elements mentioned above
they move onto stromatolites , bacterial colonys that live on the shore and show living ones today
mentions 1.5 billion speices of bacteria ut only 1% discovered
I notice that they always have circle a person 12 times with a camera before they say who they are
She is a major geek but takes us to boiling mud pits in bolivia and tells of bacteria that live there
Showing link with UV levels and expose naked DNA ,and results in it being destroyed then discover pigments that protect and results that UV could be the factor in kick starting life
Electic storms tested and experiment shows water with an atmosphere of methane hygrogen and nitrogen subjected to electric shocks overnight which fill the water with new amino acids and change its colour
shows the underwater vents ,proving sunlight isnt needed
shows experiments creating organic materials and report on a distinctive smell and more importantly molecular cell structures
metabolisim , most important chemical reaction in life
scientist to start life from scratch in big experiment
overview seems to point at comets , not meteorites , seeded the earth and volcanic,electric and UV played a major part |
And the name of the documentary was ... :toothless |
|
|
|
|
