1.5 billion-year-old Earth had water everywhere, but not one continent, study suggests
By: Mindy Weisberger - SPACE.com (originally published by Live Science)
Science continues to discover Biblical descriptions of how the Earth formed and life began.
S E E D E D C O N T E N T
What did Earth look like 3.2 billion years ago? New evidence suggests the planet was covered by a vast ocean and had no continents at all. Continents appeared later, as plate tectonics thrust enormous, rocky land masses upward to breach the sea surfaces, scientists recently reported. They found clues about this ancient waterworld preserved in a chunk of ancient seafloor, now located in the outback of northwestern Australia.
Around 4.5 billion years ago, high-speed collisions between dust and space rocks formed the beginnings of our planet: a bubbling, molten sphere of magma that was thousands of miles deep. Earth cooled as it spun; eventually, after 1,000 to 1 million years, the cooling magma formed the first mineral crystals in Earth's crust.
Meanwhile, Earth's first water may have been carried here by ice-rich comets from outside our solar system, or it may have arrived in dust from the cloud of particles that birthed the sun and its orbiting planets, around the time of Earth's formation.
When Earth was a hot magma ocean, water vapor and gasses escaped into the atmosphere. "It then rained out from the atmosphere as conditions got cool enough," said lead study author Benjamin Johnson, an assistant professor in the Department of Geological and Atmospheric Sciences at Iowa State University.
"We can't really say what the source of the water is from our work, but we do suggest that whatever the source, it was present when the magma ocean was still around," Johnson told Live Science in an email.
In the new study, Johnson and co-author Boswell Wing, an associate professor of geological sciences at the University of Colorado Boulder, turned to Panorama's unique landscape in the Australian outback. Its rocky scenery preserves a hydrothermal system dating to 3.2 billion years ago, "and records the entire ocean crust from the surface down to the heat engine that drove circulation," Johnson said.
Preserved in that craggy seafloor were different versions, or isotopes, of oxygen; over time, the relationship between these isotopes can help scientists decode shifts in ancient ocean temperature and global climate.
However, the scientists uncovered something unexpected through their analysis of more than 100 sediment samples. They found that 3.2 billion years ago, oceans held more oxygen-18 than oxygen-16 (the latter is more common in the modern ocean). Their computer models showed that on a global scale, continental land masses leach oxygen-18 from the oceans. In the absence of continents, the oceans would carry more oxygen-18. And the ratio between these two oxygen isotopes hinted that at the time, there were no continents at all, the study found.
"This value is different than the modern ocean in a way that can be explained most easily by a lack of emergent continental crust," Johnson said in the email.
Other researchers have previously proposed the idea that Earth was once ocean covered, Johnson said. However, there's less agreement about how much of that crust was visible above sea level. This new discovery "provides actual geochemical constraints on the presence of land above sea level," he explained.
The prospect of an ancient waterworld Earth also offers a new perspective on another intriguing question: where the planet's earliest forms of life appeared and how they evolved, the researchers wrote in the study.
"There are two major camps for the origin of life: hydrothermal vents and ponds on land," Johnson said. "If our work is accurate, it means the number of environments on land for life to emerge and evolve was really small or absent until sometime after 3.2 billion years ago."
The findings were published online today (March 2) in the journal Nature Geoscience .
Tags
Who is online
123 visitors
Maybe those stone-age religious freaks weren't so ignorant after all.
Yes they were as there is no way anyone living in the stone age would have a clue about the possible waterworld that may have existed 3.2 billion years ago, time and exaggeration has simply taken a regional flood event and turned it into a world event.
Still interesting research I look forward to confirmation studies. Lol a waterworld makes a nice addition to our history of also being a molten world, a snowball world and the forthcoming desert world
Interesting article. Thanks.
The nuts who claim the earth is only 6,000 years old have just been served the truth and they must be choking on it.
That truth has been served for a very long time; the YECs ignore
it.
In his best Dr Evil voice ...... it was a spinning sphere of molten MAGMA ..... a gazillion miles deep!
Watching the Science Chanel last night about dating coral reefs by counting the growth rings.
Evidence was presented that conclude that the earth used to spin faster resulting in 20 hour days,
and took 420 days to achieve one orbit of the sun.
They assume that different events involving comets and the moon
resulted in the modern calendar.
No mention of why, prior to the Gregorian calendar, the calendars were only 360 days...which caused calendar "drift".
The Gregorian is more of a solar calendar which had to make up for 10 days. Hence the day after October 4,1582,
was officially made October 15, 1582 and the "Church" began using the new calendar.
I'm thinking the faster rotation and shorter days was almost exclusively about the moon being closer. Remember that old classroom physics demonstration with a rotating chair? Someone sits in the chair with their hands held close and someone spins them. As they stretch their arms out their rate of rotation slows, and if they bring their arms back in they speed up again. Ice skaters do the same thing in those stationary spins.
When the moon was closer we shared a different gravitational center of mass, forcing our spin to be slightly faster.
You probably know this, but the moon is still moving away, so someday we'll have even longer days than we do now.
Well, we'll probably be long gone by then, but still.
The first ocean, ( 3.8 billion years ago from other sources ) was mostly fresh water, not becoming salty until the continents rose up and provided different minerals to be eroded down to the seas.
The saltiness of our oceans is the result of billions of years of build up of sodium and chloride ions.
Of course the planet could have been completely covered in water just after the crust started to form. With a thin crust mountains, volcanoes, and even meteor crater walls could not be supported let alone continents, so any water on a close to perfect sphere would cover the surface completely.
Don't think Earth would have been a perfect sphere.
Oops. You said "close to". Sorry.
Science continues to discover Biblical descriptions of how the Earth formed and life began.
Why preface a scientific article with a reference to the Bible? This article offers interesting scientific speculation. Why not focus on the scientific musings?
If you want to argue that the Bible is credible based on science then you should at least compare it to well-established findings in science like evolution.
Well, the comment is rather tongue-in-cheek. The Bible is one of the most widely known ancient texts that really does convey human understanding of the universe around them. And modern science really is discovering the Genesis story of the Bible. Those stone-age religious freaks weren't stupid.
No, the Bible does not convey science. But that is because the books were written before science had been invented (or discovered, if you prefer). Humans were asking the same questions and developing rational, plausible conclusions long before there was science.
Artificial intelligence and Hubble telescopes weren't available to those stone-age religious freaks. The ancients had to rely on real intelligence and their innate senses. The stories are archaic but keep in mind that humans had not invented language to describe their observations and conclusions. And the lack of adequate language meant that the ancients relied more on analogy to get their point across. The ancients displayed a well developed intellect; they weren't stupid people.
They looked around at their world as they saw it and fantasized to fill in gaps in their knowledge.
The authors of the Bible were certainly not stupid. But it is stupid, IMO, for contemporary human beings to retroactively credit them with insight on every loose coincidence while ignoring the glaring contradictions with well founded modern knowledge.
That is basic confirmation bias at play; the suppression of critical thinking to further a desired belief.
Was it coincidence? The human population was tens of millions. The means for organized and widely accepted methodology wasn't available. There weren't enough humans to even organize and refine language to adequately convey thoughts or ideas. The sparseness of population meant that making up a new word to convey a new meaning required many years to be widely adopted.
Claiming that the ancients 'fantasized' overlooks several thousand years of population growth which allowed social organization, communication, and refinements in language. Such claims display an unearned hubris.
What the ancient texts reveal is that the human intellect was as well developed as it is today. Modern humans may possess more knowledge but that is due to population growth which allowed more refined organization and dissemination of that knowledge. Modern humans aren't smarter than the ancient humans were.
Wait. What?
Nothing in the Genesis story agrees with modern science. What are you talking about?
Worse, very loose coincidence. The kind of coincidence that occurs when someone is trying to make a correlation that simply does not exist.
Actually I am recognizing that with such limited tools at their disposal, fantasy was all they had. You do not realize this??
Do you recognize that modern human beings have far greater knowledge?
The human race were using science long before the bible was written. Metallurgy is one science that is EVERYWHERE in the bible, as is astronomy and geometry. Hell, mummification is a pretty intense process that required an understanding of organic chemistry.
It's all quite fascinating. I suppose vegetation started by comets or meteorites carrying spores from other planets struck the Earth, but it would be interesting to know how aquatic life (which probably included the original vegetation) actually first started, perhaps the same way.
Vegetation (plants) evolved right here on Earth.
Here's a quick excerpt from the timeline of plant evolution on Wikipedia:
Come again?
Biblical description's of how Earth & life formed is basically something like "God did it," which doesn't really describe, much less explain anything.
As oxymoronic a statement if there ever was one, lol.
Since this is the closest science article on the front page, I will post this here.
Hey, is there any new satellites orbiting the earth right now that, as I counted, there would be 15 lined up in a row following each other about a 1/2 degree apart? Just passed over mid-michigan just after 5:30 this morning.
They may have been some of SpaceX's new Starlink sats.
Here's something from an article I just found. Apparently, astronomers aren't very happy with the idea of companies adding tens of thousands of new satellites to the night sky.
NASA wants you to photograph Starlink satellites with your smartphone
The article includes a link you can go to and find out what satellites were passing over you at that time.
If you go there and find out what you saw, then come back and let us know. I've never seen a whole string of sats moving together before. That's pretty cool (but not for astronomers, I suppose).
Yep, that's what it was. What got my attention was what I thought was the ISS passing over, then 1/2 a minute later it was passing again, and it was like now which one was the ISS, looked up again and there is was again, being these were headed NE each track was shifted westward due to earth's rotation, and then watching another ISS noticed another heading East followed close behind by another and as I looked west it was a line with satellites appearing from nowhere out of the earth's shadow, it was cool to watch as yet another ISS traveled NE. I can see how this would be an annoyance for astronomers.
Awesome. Glad I could help.
Now, if I could just figure out what those 2 big red-orange lights were that I saw moving over a nearby property in the middle of the night last summer...
Freaked me out.