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[GK86]

Full article here.

Geologists have discovered in Greenland evidence for ancient life in rocks that are 3.7 billion years old. The find, if confirmed, would make these fossils the oldest on Earth and may change scientific understanding of the origins of life.

Experts are likely to debate whether the structures described in the new report were formed biologically or through natural processes. If biological, the great age of the fossils complicates the task of reconstructing the evolution of life from the chemicals naturally present on the early Earth. It leaves comparatively little time for evolution to have occurred and puts the process close to a time when Earth was being bombarded by destructive asteroids.

They are some 220 million years more ancient than the oldest previously known fossils, also stromatolites. Those are 3.48 billion years old and were discovered in the Pilbara Craton of Western Australia.

The new report “provides the oldest direct evidence of microbial life,” said Gerald Joyce, an expert on the origin of life at the Scripps Research Institute in La Jolla, Calif.

Another expert in the early Earth’s environment, Tanja Bosak of M.I.T., said the structures do resemble modern stromatolites but their origin “will be hotly debated,” given there is no sign of certain features that might bolster the case for biological origin, such as crinkling in the layers of sediment.

Several different species of microbes are involved in stromatolite creation. The Isua structures, if indeed stromatolites, would represent fairly evolved organisms.

Dr. Nutman argues that life must therefore have originated even earlier, probably in the late Hadean stage of Earth’s history, which lasted from 4.65 billion years ago — when the planet formed from debris in orbit around the sun — to 4 billion years ago.

But the Hadean was so called because of the hellish conditions thought to have prevailed, including cataclysmic meteorite impacts that boiled the oceans into steam and turned Earth’s surface into molten lava. The largest of these impacts, at 4.5 billion years ago, tore a piece from Earth that became the moon.

It is difficult to see how life could have begun under such circumstances. But some geologists now favor a milder version of the Hadean, with the rain of asteroids quickly tapering off after the moon was formed.

This cataclysm, known as the Late Heavy Bombardment, hit Earth between 3.9 and 3.8 billion years ago.

Dr. Nutman believes life could have survived through the end of the Hadean and the bombardment. Some geologists, he notes, now think the asteroid impacts were spread over time, lessening their effects.

“The Late Heavy Bombardment is becoming less heavy as the years go by,” he said.

But others believe the bombardment was no light peppering. Evidence of these ancient craters has vanished from Earth but is still evident in the pockmarked face of the moon. And for every crater on the moon, 20 would be expected to have been made on Earth.

The moon has two craters more than 600 miles across that were created during the Late Heavy Bombardment. Some 40 craters this size may have been gouged out of our planet in the same interval, said William F. Bottke, an asteroid expert at the Southwest Research Institute in Boulder, Colo.

By comparison, the asteroid that wiped out the dinosaurs 66 million years ago left a crater only 110 miles in diameter.

If life on Earth did not begin until after the Late Heavy Bombardment, then it had a mere 100 million years in which to evolve to the quite advanced stage seen in the new fossils.

If so, Dr. Allwood wrote, then “life is not a fussy, reluctant and unlikely thing.” It will emerge whenever there’s an opportunity.

But the argument that life seems to have evolved very early and quickly, so therefore is inherently likely, can be turned around, Dr. Joyce said. “You could ask why, if life were such a probable event, we don’t have evidence of multiple origins,” he said.

In fact, with trivial variations, there is only one genetic code for all known forms of life, pointing to a single origin.

 

[kswiston]

Interesting finding. It does seem likely that at least microbial life would evolve wherever conditions allow.

 

[yencid]

i feel like the easiest way to describe this is, life always finds a way.

 

[Toxi]

Interesting finding. It does seem likely that at least microbial life would evolve wherever conditions allow.

 

[norm9]

God burying fossils to test our faith.

 

[BreezyLimbo]

hm

so if the moon comes from earth

how big was earth before it shattered into the moon? And how did the moon become spherical if it was chunks from earth?

 

[Robot Pants]

God burying fossils to test our faith.

pfft you werent there

 

[Seventy_X_Seven]

hm

so if the moon comes from earth

how big was earth before it shattered into the moon? And how did the moon become spherical if it was chunks from earth?

Also if the moon comes from Earth and there was life during this time, shouldn't it be possible to find fossils on the moon? That would be an interesting discovery

 

[Kas]

hm

so if the moon comes from earth

how big was earth before it shattered into the moon? And how did the moon become spherical if it was chunks from earth?

As it spins, over billions and millions of years, gravity slowly pulls it together and it forms a sphere.

 

[kswiston]

The earth was still molten when the moon broke off.

 

[Toxi]

Also if the moon comes from Earth and there was life during this time, shouldn't it be possible to find fossils on the moon? That would be an interesting discovery

This evidence suggests life was around 3.7 billion years ago. What became the Moon was dislodged from Earth 4.5 billion years ago. So we shouldn't expect fossils on the Moon.

 

[BreezyLimbo]

Also if the moon comes from Earth and there was life during this time, shouldn't it be possible to find fossils on the moon? That would be an interesting discovery

Yeah...theoretically there should be something on the moon that is a fossil of a microbe or something. But if it was a huge meteor that blew up the earth, maybe it was...obliterated in the explosion?

As it spins, over billions and millions of years, gravity slowly pulls it together and it forms a sphere.

That makes sense

The galaxy is biased towards spheres

 

[Toxi]

 

[Trojita]

As it spins, over billions and millions of years, gravity slowly pulls it together and it forms a sphere.

https://www.youtube.com/watch?v=HVXEi1BYmXQ

 

[BreezyLimbo]

Many years ago Madonna rose from the molten crust? Makes sense.

 

[cdyhybrid]

First signs of life appear in rocks at around the time meteors are hitting Earth.

We are aliens confirmed.

 

[smurfx]

looks like the panspermia theory might have some validity.

 

[Mistel]

hm

so if the moon comes from earth

how big was earth before it shattered into the moon? And how did the moon become spherical if it was chunks from earth?

The moon isn't just Earth it is also parts of Theia in the most commonly accepted theory. As for being spherical it accreated the ejected the matieral along with possibly three slow velocity collisions with smaller objects which added mass along with the tidal friction causing spinning making it spherical in the most basic terms.

 

[kswiston]

Also regarding the moon and the Earth's size before losing the moon, the Moon is not really that big. It looks big sitting next to the Earth, but its volume is only 2% of Earth's and its mass is a bit over 1% of Earth's. The moon was mostly formed from the lighter mantle elements of the Earth and lacks the heavy nickel-iron core. This makes it less dense than the Earth.

 

[MIMIC]

But the Hadean was so called because of the hellish conditions thought to have prevailed, including cataclysmic meteorite impacts that boiled the oceans into steam and turned Earth’s surface into molten lava. The largest of these impacts, at 4.5 billion years ago, tore a piece from Earth that became the moon.

Interesting. I never knew this.

I had to YouTube a simulation of this since I couldn't figure out what happened to the object that impacted the Earth (Earth ate it!) But it's also interesting that there are no signs of this impact (since the Earth was still forming and then REformed).

 

[omnislayer]

Wow this seems to give panspermia a little more room to stand on. Interesting.

 

[B-B-Bomba!]

Next stop: the universe itself is alive? Is life itself?

... Double guitars?

 

[Mistel]

looks like the panspermia theory might have some validity.

Panspermia has too many issues to ever have validity it merely moves the origin it can't be tested and is still very much a hypothesis.

 

[BreezyLimbo]

Interesting. I never knew this.

I had to YouTube a simulation of this since I couldn't figure out what happened to the object that impacted the Earth (Earth ate it!) But it's also interesting that there are no signs of this impact (since the Earth was still forming and then REformed).

If it was molten, I imagine it was like clay before solidifying, that is the crater of the part that got broken off just...got filled with lava again

 

[Mineshaft_Gap]

hm

so if the moon comes from earth

how big was earth before it shattered into the moon? And how did the moon become spherical if it was chunks from earth?

Gravity. The moon has sufficient mass for gravity to shape the moon into a spherical shape.

 

[Cosmo Clock 21]

Best chapter.

 

[Tal Shiar Agent]

Life here began out there.

 

[SwiftDeath]

So Aliens

 

[Saucycarpdog]

God burying fossils to test our faith.

I just imagine god putting things on the earth so he can record our reactions to it and upload them to YouTube.

"Homosapiens react to really old bacteria!"

 

[Yagharek]

If the raw materials for life were so abundant that it emerged on earth quickly, that would mean stars in the neighbourhood of our sun must also stand a good chance of having those ingredients. The supernova that seeded the local bubble obviously left behind a handy chemical lab.

 

[Bombless]

Ha! Tom was right all along!

 

[googleplex]

Wandering Eye.

Also, every one should read Gunnerkrigg Court

 

[kswiston]

If the raw materials for life were so abundant that it emerged on earth quickly, that would mean stars in the neighbourhood of our sun must also stand a good chance of having those ingredients. The supernova that seeded the local bubble obviously left behind a handy chemical lab.

Life is mostly made of the most common elements in the universe. By this point, every planet similar to ours is going to have the required materials.

 

[Toxi]

Wandering Eye.

Also, every one should read Gunnerkrigg Court

Gunnerkrigg Court is da best.