Researcher says Earth's oceans 'homegrown'

Researcher says Earth's oceans 'homegrown' - UPI.com
"Astronomers have long theorized that comets and asteroids delivered the
water for the world's oceans during an epoch of heavy bombardment that
ended about 3.9 billion years ago, but researchers at Massachusetts
Institute of Technology contend the water came from the very rocks that
formed the planet, AAAS ScienceMag.org reported Monday."
http://www.upi.com/Science_News/2010...6321291164698/

On 12/1/10 12:23 AM, Yousuf Khan wrote:
Researcher says Earth's oceans 'homegrown' - UPI.com
"Astronomers have long theorized that comets and asteroids delivered the
water for the world's oceans during an epoch of heavy bombardment that
ended about 3.9 billion years ago, but researchers at Massachusetts
Institute of Technology contend the water came from the very rocks that
formed the planet, AAAS ScienceMag.org reported Monday."
http://www.upi.com/Science_News/2010...6321291164698/


Earth Oceans Were Homegrown
New model suggests that our seas didn't come from comets and asteroids

http://news.sciencemag.org/scienceno...homegrown.html

"Astrobiologists have been continually surprised by how quickly life
evolved on Earth—within 600 million years after the planet's formation,
or about 3.9 billion years ago. Elkins-Tanton's findings may help
explain why. "If water oceans were present shortly after the impact that
formed the moon [some 4.45 billion years ago]," says Dirk
Schulze-Makuch, an astrobiologist at Washington State University,
Pullman, "much more time would be available for the evolution of life,
and it would explain why life was already relatively complex when we
find the first traces of it in the rock record."

On Dec 1, 1:32*am, Sam Wormley wrote:
On 12/1/10 12:23 AM, Yousuf Khan wrote:

Researcher says Earth's oceans 'homegrown' - UPI.com
"Astronomers have long theorized that comets and asteroids delivered the
water for the world's oceans during an epoch of heavy bombardment that
ended about 3.9 billion years ago, but researchers at Massachusetts
Institute of Technology contend the water came from the very rocks that
formed the planet, AAAS ScienceMag.org reported Monday."
http://www.upi.com/Science_News/2010...ays-Earths-oce...

Earth Oceans Were Homegrown
New model suggests that our seas didn't come from comets and asteroids

http://news.sciencemag.org/scienceno...ans-were-homeg...

"Astrobiologists have been continually surprised by how quickly life
evolved on Earth within 600 million years after the planet's formation,
or about 3.9 billion years ago. Elkins-Tanton's findings may help
explain why. "If water oceans were present shortly after the impact that
formed the moon [some 4.45 billion years ago]," says Dirk
Schulze-Makuch, an astrobiologist at Washington State University,
Pullman, "much more time would be available for the evolution of life,
and it would explain why life was already relatively complex when we
find the first traces of it in the rock record."

Sam I haVE POSTED that rock planets are older than the Sun Earth was
captured by the Sun as it came out of the Oort cloud It was a
comet. First definition of a comet is its frozen ice. The Earth
fits TreBert My Dell has a virus attact

On 12/1/10 7:03 AM, bert wrote:
My Dell has a virus attact

I often think that licenses should be required for computer
owners, before they can connect a computer to the internet.

http://www.cert.org/tech_tips/home_networks.html
http://edu-observatory.org/olli/hcs/index.html

On Nov 30, 10:23*pm, Yousuf Khan wrote:
Researcher says Earth's oceans 'homegrown' - UPI.com
"Astronomers have long theorized that comets and asteroids delivered the
water for the world's oceans during an epoch of heavy bombardment that
ended about 3.9 billion years ago, but researchers at Massachusetts
Institute of Technology contend the water came from the very rocks that
formed the planet, AAAS ScienceMag.org reported Monday."http://www.upi.com/Science_News/2010/11/30/Researcher-says-Earths-oce...

There are two ways to form rocks, and both of them require water.
For example, silicon and zirconium exit seafloor volcano. On
contact with water, silicon hydrates into silicate, which precipitates
as zirconium silicate or zircon.
http://www.pmel.noaa.gov/vents/chemi...ges/vents2.gif
In the second method, silicon and zirconium exit an open-air volcano
and are burned by atmospheric oxygen into silicon dioxide (quartz)
and zirconium dioxide (zirconia). Since atmospheric oxygen is
derived from the lysis of water, water is both the precursor and the
primary ingredient of rocks. Perhaps, early Earth was more like a
gas giant (Neptune, Uranus) which shed its atmosphere due to
proximity to the Sun. John Curtis

On 01/12/2010 11:54 AM, John Curtis wrote:
There are two ways to form rocks, and both of them require water.
For example, silicon and zirconium exit seafloor volcano. On
contact with water, silicon hydrates into silicate, which precipitates
as zirconium silicate or zircon.
http://www.pmel.noaa.gov/vents/chemi...ges/vents2.gif
In the second method, silicon and zirconium exit an open-air volcano
and are burned by atmospheric oxygen into silicon dioxide (quartz)
and zirconium dioxide (zirconia). Since atmospheric oxygen is
derived from the lysis of water, water is both the precursor and the
primary ingredient of rocks. Perhaps, early Earth was more like a
gas giant (Neptune, Uranus) which shed its atmosphere due to
proximity to the Sun. John Curtis

I think if Earth were that massive, then it would've been able to hold
onto this huge atmosphere with the gravity of the atmosphere itself.

Since it doesn't have that huge of an atmosphere now, it's likely it
never did.

Yousuf Khan

On 01/12/2010 1:32 AM, Sam Wormley wrote:
"Astrobiologists have been continually surprised by how quickly life
evolved on Earth—within 600 million years after the planet's formation,
or about 3.9 billion years ago. Elkins-Tanton's findings may help
explain why. "If water oceans were present shortly after the impact that
formed the moon [some 4.45 billion years ago]," says Dirk
Schulze-Makuch, an astrobiologist at Washington State University,
Pullman, "much more time would be available for the evolution of life,
and it would explain why life was already relatively complex when we
find the first traces of it in the rock record."

Even if the water on Earth were delivered by comets during the Late
Heavy Bombardment phase, that still provides more than enough time for
life to start 3.9 billion years ago.

Yousuf Khan

See: http://www.pbs.org/wgbh/nova/transcr...1_origins.html

But when did a planet that looks like the Earth we know begin to take shape?

Earth's hot molten surface took at least a billion years after the moon
was created to cool and form a thick skin, its crust, or so scientists
believed. But no one knew for certain because Earth is such a
geologically restless place that none of the original crust survives today.

Yet startling new evidence is causing a major rethinking of when Earth's
crust first formed. The clues to this mystery are embedded within these
rocks in Western Australia. Here, geologists have extracted tiny
crystals called zircons. About the size of sand grains, zircons are
nearly as tough as diamonds. These relics of the early Earth formed when
molten rock cooled into solid crust, so the age of the zircon gives you
the age of the crust itself.

And it was here that geologist Simon Wilde hit pay dirt when he found
one crystal so old he's convinced it was formed in the Earth's original
crust.

SIMON WILDE (Curtin University of Technology): When we look at the
chemistry in detail, from the zircons in this rock, we find that it's
consistent with having grown in a piece of continental crust.

NEIL deGRASSE TYSON: Radioactive dating shows that the oldest of the
zircons Simon Wilde found in these hills is 4.4 billion years old,
suggesting that Earth might have cooled and formed a crust soon after
the moon was formed.

SIMON WILDE: We don't know, of course, whether the continental areas
were extensive or whether they were just small little islands of
material. But certainly what we do know is that there was continental
crust at 4.4 billion years ago.

NEIL deGRASSE TYSON: This was just 150 million years after Earth was
born, not a billion years as previously thought. But that led to another
mystery: once Earth was cool enough to form solid ground, water could
collect on its surface, so when did that happen?

Geologists, including Stephen Mojzsis, think the answer may lie in these
same tiny zircon crystals. Zircons are extremely rare, so to find just a
few crystals, Mojzsis had to pulverize and sift through hundreds of
pounds of ancient rocks.

An analysis of the chemical composition of the crystals revealed that
the oldest zircons contained a high concentration of a curious
ingredient. It was a type of oxygen called Oxygen-18, an isotope that
could only be present in large quantities if the zircon crystals had
grown in water.

The news that water might have been present so early in Earth's history
was a bombshell.

STEPHEN MOJZSIS (University of Colorado): Not only was there crust
present, which came as a surprise to most of us, it looks like, from
some of the zircons, that that crust interacted with large volumes of
liquid water.

NEIL deGRASSE TYSON: The idea that water settled on Earth's surface so
soon is controversial, but if true, it suggests a planet much more like
today's than anyone had ever imagined.

STEPHEN MOJZSIS: By 200 million years after the formation of the Earth
you can imagine a landscape of islands and small continents, bathed by a
primitive ocean.

NEIL deGRASSE TYSON: The time was only 10 minutes to one in the morning;
the moon existed and so did a planet with not just land but water.

Liquid water is the key to life; every living thing requires it to
survive. And eventually, water would cover nearly three quarters of the
Earth's surface. In fact, all the world's oceans contain nearly one
hundred million trillion gallons of it. It's an almost incomprehensible
amount.

So, where did it all come from? How would Earth have ended up with such
vast quantities of this stuff?

Well, strange as it sounds, these great oceans may have been there from
the very beginning, just hidden away.

One key to the riddle was volcanoes, which, throughout Earth's infancy,
pumped huge amounts of steam into the atmosphere. Then, as Earth cooled,
that steam condensed into rain. Drop by drop, water collected in
low-lying areas.

DAVE STEVENSON: There is nothing mysterious or surprising about this.
The Earth does it right now. The main gas that comes out of Hawaiian
volcanoes is water, steam. So, this is happening all the time.

NEIL deGRASSE TYSON: But some scientists argue it would take far too
long to create such vast oceans by volcanic outgassing. Instead, Earth
may have had some help.

The water in our oceans might have come from outer space, delivered to
the surface by massive ice-bearing comets. The evidence for these
ancient impacts is impossible to find today, since the original surface
of our planet has long since been eroded or destroyed. But there's one
place that preserves a record of impacts from that early era: our moon.

BILL HARTMANN: Every one of those craters was a meteorite explosion at
some time.

NEIL deGRASSE TYSON: The moon's surface is littered with craters, some
of them hundreds of miles across. In fact, the moon was ravaged by more
than a million major impacts in its early years. Since Earth is much
more massive, its gravitational pull would have attracted even more
debris, resulting in possibly tens of millions of impacts.

BILL HARTMANN: We all hear about the impact 65 million years ago that
wiped out the dinosaurs. And you're getting that kind of impact
something like once a month on the early Earth. But this rain of debris
left over from the formation of the solar system continues for several
hundred million years.

NEIL deGRASSE TYSON: And in this cosmic debris field, comets containing
huge amounts of dust and ice would have been plentiful, like dirty
snowballs the size of mountains. Roughly half their mass was water.

One NASA scientist, Michael Mumma, wonders if these comets were the
source of the water in Earth's oceans.

MICHAEL MUMMA (NASA Goddard Space Flight Center): One possibility is
that Earth's water was delivered by the impact of bodies from beyond the
Earth. These would naturally be the comets, which are rich in water. The
proof in that would be to measure the composition of the cometary water
and to compare that with the composition of water in our oceans.

NEIL deGRASSE TYSON: But studying comets is a tricky business. In the
last 20 years, just a handful have passed close enough to study in
detail, including one in 1997 called Comet Hale-Bopp.

MICHAEL MUMMA: A comet like Hale-Bopp would deliver about 10 percent of
the water needed to fill one of the Great Lakes. This is a lot of water.
Of course the oceans are much larger, and so we need many more comets to
fill the oceans. But we're fortunate; we had many such comets in the
early solar system, so we have every reason to believe it was cometary
delivery that brought water to the early Earth.

NEIL deGRASSE TYSON: Mumma thinks that the heat of an impact would have
evaporated the ice within a comet, creating storm clouds over vast areas
of the planet. These clouds produced a deluge of hot, possibly acidic
rain that continued for millions of years. At first the rain would have
formed lakes and rivers, and eventually water would cover almost the
entire globe.

But there's a problem with this theory. Earth's oceans contain a mixture
of normal water, H2O, and a much smaller amount of a more exotic kind,
known as HDO, or heavy water which contains an extra neutron.

In the comets analyzed so far, the proportions of these two kinds of
water don't match the composition of water in our oceans.

MICHAEL MUMMA: They have twice the amount of heavy water that we see in
Earth's oceans so if they were the comets that delivered the Earth's
oceans they wouldn't fit the bill. Basically, they don't have the right
properties.

NEIL deGRASSE TYSON: But Mumma hasn't given up. The comets already
studied come from the outer reaches of the solar system, and he thinks
comets originating closer to the sun might be different. Formed at
higher temperatures, these comets could have a lower proportion of heavy
water more closely matching our oceans. And tonight, Mumma hopes to test
this idea by getting a first hand look at one of these elusive comets.

MICHAEL MUMMA: If its chemistry is different, and if the heavy water to
light water is like that on Earth, it would be the first proof positive,
or the "smoking gun" evidence, that comets did in fact deliver water to
the early Earth.

NEIL deGRASSE TYSON: But first, the team has to hunt down the comet.

MICHAEL MUMMA: As soon as he has acquired it, we should see an image of
it on the screen. There it is alright, yes sir, right there. You can see
the elongated material flowing outward from the nucleus.

Joe, that looks excellent.

NEIL deGRASSE TYSON: With the comet in the crosshairs of their telescope
they can home in on the kind of water it's carrying.

MICHAEL MUMMA: People often ask, "How can you measure water in an object
that is a hundred million miles away?" We do this by a method called
spectroscopy. It's a little bit like taking fingerprints; the little
ridges on your fingers look different for every person. And in the same
way, the light that is emitted by a given molecular compound is
different; it emits at different wavelengths.

NEIL deGRASSE TYSON: But it turns out this comet is a very dirty
snowball indeed. There's so much dust on the surface that it can't
reflect enough light for the team find out what kind of water is on board.

MICHAEL MUMMA: It did not brighten as expected. This was a bit of a
disappointment. Comets are quite fickle, they're unpredictable. In some
ways they are like cats, they both have tails and they both do what they
want to.

NEIL deGRASSE TYSON: But with astronomers finding two or three comets a
year from the inner part of the solar system, Mumma could soon have
another chance to test his controversial ideas about the origin of
Earth's oceans.

MICHAEL MUMMA: One of the key things that every scientist keeps in mind,
is you should never fall in love with your theory. So it's an idea, it's
a hypothesis, it fits all the known facts. But it has not yet been
proven, and we must be willing to give it up and modify it if it is not
proven. But we will learn something in doing so.

DAVE STEVENSON: It's still possible that comets played a role. In fact,
it's hard to imagine that they played no role. But it seems more likely
and more physically sensible to look closer to home for the source of
the water.

NEIL deGRASSE TYSON: Besieged by volcanoes and battered by impacts,
Earth endured its most extreme punishment in its early years. It was
beaten, bombarded, mangled, and melted all in just the first hour of our
24-hour history of the planet.

The young Earth was still very different from the planet we know today.
It was a hostile and forbidding place, with an atmosphere full of
poisonous gases. Yet, somehow, these harsh conditions set the scene for
a crucial phase of Earth's development: the origin of life.

STEPHEN MOJZSIS: Very little is left behind from the Earth's earliest
time period, but what is left behind has revealed to us a planet much
more complicated than we ever thought, with different rock types, liquid
water present and the kind of planet that we might expect life to emerge on.

On Dec 1, 12:10*pm, Yousuf Khan wrote:

I think if Earth were that massive, then it would've been able to hold
onto this huge atmosphere with the gravity of the atmosphere itself.

Since it doesn't have that huge of an atmosphere now, it's likely it
never did.
Maybe the protoearth was like that initially, but lost it due to
collision.
Supposedly there was a collision with a Mars like body that
created the moon. A collision like that would have removed the
atmosphere of the protoearth. The atmosphere would have to have
developed after the collision.

On Dec 1, 9:17*am, Sam Wormley wrote:
See:http://www.pbs.org/wgbh/nova/transcr...1_origins.html

But when did a planet that looks like the Earth we know begin to take shape?

For 2 billion years Earth was submerged in a deep global ocean.
Seafloor volcanoes were producing basaltic rocks only until the
Proterozoic, when things changed. Enough ocean water had
been destroyed (lysed) by then to lower the ocean's surface
closer to seafloor volcanic peaks. Oxygen from lysed water
filled the atmosphere (the great oxygen surge). At lower depths
(pressures) silicon is no longer soluble in water and bubbles
to the surface where on contact with oxygen it forms SiO2
in the form of sand and pumice (continental rocks).
http://www.snopes.com/photos/natural/maiken.asp
http://earthobservatory.nasa.gov/IOTD/view.php?id=7124
Other gases such as methane and hydrogen sulfide are also
less soluble and bubble to the surface, where on contact with
oxygen they ignite into CO2 and SO2 leading to the formation
of limestone and gypsum respectively. John Curtis