How to Analyse Past Atmospheres

I came across THIS ARTICLE and found it very interesting. It describes methods used to extract and analyse gases trapped in rocks and minerals. The gases are in  various salts, quartz and crystallized magmas.

The technique used sounds simple - crush the rock and collect the gas. But it has to be done in a vacuum-sealed press and send the released gas to a mass spectrometer for analysis. The gas does not all come out at once but in pulses as different parts of the sample fail. Repeat and repeat until you have enough gas. The crushers are very small - 10 grams of rock is considered "an insane quantity"!

Crush Archaean rocks and with care you can get a sample of Archaean air. Its age can be proved by radiometric dating of the included noble gas isotopes. There have been some surprises - higher oxygen levels appearing earlier than expected.

But read the article to get an introduction to this fascinating subject.

 Is There Helium in the Core?

A correspondent sent me THIS LINK which seems to link three opposites. Helium is a very light noble gas which does not mix with anything, iron is a metal and the earths core is hot, pressurised and a long way away. But there are hints that all is not as one assumes!

The rare (at the Earths surface) form of helium is He-3 (2 protons, one neutron) is found during volcanic eruptions. Where did it come from? Is it left over from the Big Bang? 

In normal circumstances you can find a few parts per million of helium in iron. The experimenters decided to look at conditions similar to those of the Earth' core. For this they used a laser heated diamond anvil cell. And found that they could get 3.3% helium into iron.

If this is what actually happens in the core it has implications for what happened as the Earth formed. And it may mean that the helium from volcanic action came from the core and not from, as yet unfound, reservoirs. What I find mind boggling is the scaling up from tiny experimental quantities to the Earth's core!

 Was Human Life Dependent on Five "Hard Steps"?

I wish I knew! THIS PAPER suggests not, but first of all - What Are The Five Steps? They are the things which had to happen for human life to exist. And it is soon evident that much academic blood has been spilled over the compilation of the list. But here is one version of it.

1. Life (abiogenesis)
   
   
2. Oxygenic photosynthesis
   
   
3. Eukaryotic cells - fusion of a Bacteria with an Archaea
   
   
4. Animal multicellularity
   
   
5. Homo sapiens

The order of the steps is fixed. Steps 1, 3 and 4 are evolutionary steps, 2 and 5 are not. Various other steps have been proposed but five seems a good number. A definition of a hard step is:- Improbable, and essential for the evolution of humanity.

These hard steps are fairly evenly distributed over the life of the Earth.

The authors of this article suggest that these singularities are the result of the global-enviromental processes. They may have happened once but the happening was inevitable.

This is a very interesting article and you need to read it to get an appreciation of the knowledge used in it. But the conclusion seems to imply that human like beings should be fairly common in the universe. So far we have discovered only us. Are the authors wrong or is there something preventing intragalactic communication?

 Down to Earth Extra March 2025

The March 2025 edition of Down to Earth Extra has been published. You can download it HERE or you can read it below.

 Does the Inner Core Change Shape?

And if it does, how do we tell and does it matter? The Inner Core is solid, the Outer core is liquid. Both are thought to be largely iron. The Core is responsible for the Earth's magnetic field, without which life on Earth would not be possible. And it is studied by using earthquakes, specifically those in the South Sandwich Islands and recorded in Northern Canada, passing through the earth's core on their way.

There is no shortage of South Sandwich earthquakes and many are very similar. Over the years their signature in Northern Canada has shown differences. The differences have been attributed to the Inner Core rotating at different speeds and lately the differences have been thought to be because of changes to the cores shape.

The above is a very superficial reading of the research. If you want to know more there is the BBC ARTICLE which is based on this SCIENTIFIC PAPER. The diagram below might help to understand the research.

 Jurassic Coast Trust to Close

A correspondent alerted me to this. Details can be found on THIS BBC WEBPAGE. At least the Jurassic Coast is still open. But it is very sad.

 Down to Earth Extra February 2025

The February 2025 edition of Down to Earth Extra has been published. You can download it HERE or you can read it below.

 Fish Vomit Fossilised

A correspondent sent me THIS LINK, for which I thank him. It concerns the find by an amateur fossil hunter of what turned out to be fish vomit. It consist of all the indigestible bits of what some fish had eaten. You can see bits of crinoid.

It comes from Stevns Klint which has some renown as a place where the contact between the Cretaceous and Paleogene can be seen, with its iridium enriched layer.

The specimen comes from the Cretaceous and helps us envisage life beneath the waves at that time.

The Fabulous Triassic 

A correspondent has brought THIS ARTICLE to my attention. It is from the Christmas edition of The Economist. You may have to go through some hoops to read it but you should get in without much difficulty.

And it is worth reading as it gives an overview of the Triassic AND it quotes Mike Benton!

The articles contention is that, although often overlooked, it is the period that led to the world as we know it. And it is fun to read!

 Why the Earth is Not Like Venus

At first glance the Earth and Venus should be similar and have geology with more resemblances than differences. A closer look tells us that it is a very different place.

The longest any lander has survived on Venus is 2 hours. We have been on Earth for rather longer. The surface temperature is about 465⁰C, the atmosphere is mostly carbon dioxide and there is virtually no oxygen and water.

Orbiters have used radar to look at the surface and conclude that it is mostly wrinkled plains of lava. There are lots of volcanoes and some are very large.

THIS ARTICLE will tell you all you need to know about the place; and comes to the conclusion that the crucial difference with the Earth is the lack of a magnetic field of any great strength.

Most of the lighter elements - especially hydrogen and oxygen - have been lost to space by the action of the solar wind. The atmosphere has been eroded of all its lighter components, leaving carbon dioxide and thus a runaway greenhouse effect.

The Earth's magnetic field protects the atmosphere from the solar wind. It has had a magnetic field for at least 3.7 billion years. 

Are Vast Amounts of Hydrogen Fuel Hidden Below Earth's Surface?

 

Are Vast Amounts of Hydrogen Fuel Hidden Below Earth's Surface?

The short answer is that we do not know! A longer answer can be found in THIS New Scientist Article.

A couple of emails ago I wrote about using ophiolites to produce hydrogen. Many people believe that you do not need to do that as there should be lots of hydrogen lurking below the earths surface. There is talk about quadrillions of tonnes. But so far only one deposit is known - (in Mali).

Finding other deposits is proving to be very difficult - unless they have been found and the finders are keeping quiet! We do not want to go down that rabbit hole! (A bore hole surely!)

I hope more evidence appears soon and we can stop following speculation.