Saturday 23 October 2021

Were Dinosaurs Good Neighbours?

Were Dinosaurs Good Neighbours? 

A correspondent has sent me THIS LINK - many thanks. In it Mike Benton discusses whether dinosaurs were social animals. The basis of his discussion is THIS PAPER. the researchers have found and described a site in Patagonia where they found nests with eggs and the skeletons of Mussaurus patagonicus. The skeletons ranged from babies to adults. The age is given as 193 million years.

The nests were spaced at a distance consistent with the animals size - close but not too close. It is suggested that they returned to the site regularly. There is evidence that it is a life assemblage - at least for the eggs - perhaps a dust storm buried the eggs. The skeletons are mostly complete and therefore are at the place they died.

So did these dinosaurs live in family groups? Mike Benton is beginning to think so - dinosaurs were warm-blooded, feathered, fast-moving and had sophisticated behaviour.

The research team studied fossils at an early Jurassic site in Patagonia, Argentina. Alejandro OTero

Thursday 14 October 2021

Two Contrasting Landslides

Two Contrasting Landslides 

I came across these two articles on The Landslide Blog

THE FIRST is probably the slowest landslide measured - 2mm per year. It is big - a block of limestone 900m by 400m sliding over a layer of clays and marls. It is in Tunisia and it looks spectacular. Obviously a still photograph rather than a video.

THE SECOND is rather faster. It occurred in the Dolomites on the 9th October at the Punta dei Ross, Croda Marcora.

It becomes rather hectic at the 38 second mark. The measurements become m per sec rather than mm per year.

Both landslides are fascinating.

Saturday 9 October 2021

The Moon's Youngest Rocks

 The Moon's Youngest Rocks

A Chinese Moon lander has come back with the youngest rocks yet found on the Moon. 1.97 billion year old basalt lavas, to be precise. This age is a lot younger than anyone had predicted. Where did the heat come from to produce liquid magma? Tidal heating is today's hot prediction, but nobody really knows. 

The rocks were retrieved by the Chang'e-5 mission which landed on the moon in December 2020. Read all about it HERE

The site for the lander was selected by counting craters! The less the crater density, the younger the surface. The age found vindicates this method of dating the relative ages of areas of the Moons surface.

Explaining the age of the lava should keep people busy for ages!

The landing site. CNSA Lunar Exploration and Space Engineering Center, Author

Thursday 7 October 2021

Earthshine Decreasing

Earthshine Decreasing 

The reason we are able to see a new Moon is because it is lit by reflected light from the Earth - earthshine. The amount of earthshine is controlled by the Earth's albedo - the higher the albedo the more earthshine. In the last ice age the albedo was high as ice is a good reflector. Cloud cover acts in the same way. 

The source of the light is, of course, the Sun. And with light comes heat. Generally 30% of the solar energy hitting the Earth is reflected - the albedo at work.

How do you measure the albedo? THIS ARTICLE based on THIS PAPER tells you how and it is based on measuring earthshine. (Jokes about moonshine will not be tolerated!) The investigators have been measuring earthshine on the moon since 1998 and have found that it has decreased by an amount indicating a 0.5% decrease in the albedo. A decrease in the energy reflected out indicates an increase in the energy received by the Earth.

In the ice ages high albedo encouraged cooling; now the decreasing albedo is increasing global warming.

Surprisingly the change in the albedo is attributed to a shortage of low altitude clouds over the eastern Pacific.