PDA

View Full Version : Source of Earth water



herocomplex
2004-Nov-05, 11:14 PM
I'm curious about the origin of Earth's water. It appears that current theories advocate much of it came from comets (which was bolstered by comet LINEAR releasing water of the same type as Earth), but Earth seems to have an AWFULLY large amount of water. Are other sources considered? Are there ideas as to why Earth might have so much more water than the other planets? Thanks everyone. Keep on fighting the good fight....to rid the world of ignorance.

Leper
2004-Nov-06, 01:19 AM
I don't think earth has more water, It is less tha 1 percent of the mass of the planet. Titan has a water core, the rings of saturn are water, the clouds on venus have lots of water content( I don't want to get into the rest) Europa has lots of water, we just have liquid at this temp and pressure is all.

01101001
2004-Nov-06, 02:06 AM
Hey, let's ask a scientist (http://newton.dep.anl.gov/aasquesv.htm)!

Water's Origin (http://www.newton.dep.anl.gov/askasci/env99/env155.htm)


The original source of water on earth probably began some 4.5 billion of years ago when the planet was being formed. Scientists consider 3 possible sources for water, namely:

separated from the rocks that made the bulk of earth;
arrived from outer-space, as part of meteorites;
arrived from outer-space, as part of comets.

These still are theories, mostly because outer-space water sometimes is not exactly the same kind of "our" water (for example, the hydrogen is heavy isotope deuterium).

eburacum45
2004-Nov-06, 07:56 AM
Almost every world in our solar system probably started out with a high water content; Venus lost its water by photodissociation, Mars lost it because of its low gravity;

but Uranus, Neptune, Titan, Ganymede, Callisto, Triton, Pluto, Europa... all these worlds have vast reserves of water, almost all as ice.

Even Earth probably lost a good proportion of its water when it suffered the impact that formed the Moon; there is less water on Earth than there might have been, and some more water in the form of comets may have fallen onto Earth after the impact to top up the oceans.

It may be that if the Earth had not lost all this water during the impact the Earth may have become a water world;

with a higher water vapour content in the atmosphere we might have become a moist greenhouse world, warming up so much that the atmosphere could become a hothouse like Venus, and perhaps the hot atmosphere would dry out just as Venus has.

Chip
2004-Nov-06, 12:22 PM
...Even Earth probably lost a good proportion of its water when it suffered the impact that formed the Moon...It may be that if the Earth had not lost all this water during the impact the Earth may have become a water world...

I think the theory describing the impact which eventually formed the moon, has it happening before there were any oceans on Earth. The Earth was still molten at the time. (That's the theory at least. I wasn't there in my present form - to witness it.) :wink:

dgruss23
2004-Nov-06, 03:00 PM
It may be that if the Earth had not lost all this water during the impact the Earth may have become a water world;



In which case we wouldn't be here discussing this! :D

One more reason to enjoy the Moon!

2004-Nov-06, 03:52 PM
I don't think earth has more water, It is less tha 1 percent of the mass of the planet. Titan has a water core, the rings of saturn are water, the clouds on venus have lots of water content( I don't want to get into the rest) Europa has lots of water, we just have liquid at this temp and pressure is all.

I am puzzled by the comment about Venus. H2SO4 is not H2O. When I did a google I found comments about the dryness of the Venus atmosphere but I also found a site
http://teacher.scholastic.com/researchtools/articlearchives/space/inplan.htm
saying the only water was water vapour.

2004-Nov-06, 04:12 PM
What is it the YECs call it? God, I've forgotten....How remiss of me! :lol:

Evan
2004-Nov-06, 05:11 PM
There is far more water on Earth than it appears. More is tied up in carbonates, hydrates and clathrates than exist in the liquid form. Also, there may be more actual liquid water below the surface than is above it.

Water isn't exactly scarce in the solar system. Look at Enceladus (http://en.wikipedia.org/wiki/Enceladus_(moon)) for example. The mean density is 1.3 which suggests it is nearly all water.

George
2004-Nov-06, 05:26 PM
There is far more water on Earth than it appears. More is tied up in caronates, hydrates and clathrates than exist in the liquid form. Also, there may be more actual liquid water below the surface than is above it.

Yep. IIRC, the Kola Borehole is still the deepest hole ever drilled (12.2 km by Russia) and they were surprised to see such water saturation at that deep.

Brady Yoon
2004-Nov-11, 06:44 AM
Is there a definite number on what percentage of Earth's water is on the surface and underground?

Evan
2004-Nov-12, 04:42 PM
I don't recall where I saw it but do recall seeing an estimate that there may be as much as five times more water tied up in the Earth in various forms including liquid ground water as there is in the oceans and atmosphere. Minerals like calcium carbonate cannot form without water and these minerals are ubiquitous.

Argos
2004-Nov-12, 05:38 PM
I'm curious about the origin of Earth's water. It appears that current theories advocate much of it came from comets (which was bolstered by comet LINEAR releasing water of the same type as Earth), but Earth seems to have an AWFULLY large amount of water.

Some say that the rate of comet impact alone could account pretty well for all the water on Earth.

Humphrey
2004-Nov-12, 07:34 PM
Volcanoes also account for some of the earth surface water.

Brady Yoon
2004-Nov-14, 06:50 AM
Adding onto what Argos said, There was an article I vaguely remember that said "mini-comets" have been hitting the Earth ever since it was formed, which were about 40 feet wide. It said that even these tiny comets could account for all the water.

Evan
2004-Nov-14, 08:31 AM
Uhh... The carbonates, the clathrates and the various hydrates have been around for a long, long time.

Time Scale (http://www.geo.ucalgary.ca/~macrae/timescale/timescale.html)

sarongsong
2004-Nov-20, 06:29 AM
Adding onto what Argos said, There was an article I vaguely remember that said "mini-comets" have been hitting the Earth ever since it was formed, which were about 40 feet wide. It said that even these tiny comets could account for all the water.
"...These images (http://www.aip.org/png/html/snowball.htm) support the hypothesis that Earth's water supply was created at least partly by house-sized, ice-filled comets, which strike the upper reaches of Earth's atmosphere and immediately disintegrate into water vapor...new, sharper images from NASA Polar Spacecraft...suggest that 5-30 of these comets enter the Earth every minute..."

Evan
2004-Nov-20, 08:51 AM
Partly nonsense. There are not 5 to 30 house sized "comets" striking the Earth every minute. The one shown on that site is an unusual and uncommon event. That site does a very poor job of explaining what MAY be a possible explanation. There may be thousands per day of tiny sand grain sized water containing particles, maybe. They are not comets. Also, the water is disassociated to hydrogen and oxygen. There is no particular reason for it to recombine to water.

John Kierein
2004-Nov-20, 09:14 AM
http://www.amazon.com/exec/obidos/tg/detail/-/1559720336/qid=1100942007/sr=1-2/ref=sr_1_2/103-0509452-3567845?v=glance&s=books
Lou Frank's controversial book.

sarongsong
2004-Nov-20, 09:11 PM
...That site does a very poor job of explaining what MAY be a possible explanation...
Maybe so, but they DID present it as a question.