The Health of Earth In its Development and how Hollywood Has Depicted It

 Nadene Goldfoot                                                  

At least five major ice ages have occurred throughout Earth's history: the earliest was over 2 billion years ago, and the most recent one began approximately 3 million years ago and continues today (yes, we live in an ice age!). But it's warming up!!!   Carbon dioxide is a greenhouse gas, and methane is an even more potent greenhouse gas. As atmospheric concentrations of these greenhouse gases dropped, global temperatures plummeted, plunging the planet into a series of ice ages. Over the last couple of centuries, Earth has become warmer. 

That’s because of greenhouse gases released into the atmosphere. One of the most commonly known greenhouse gases is carbon dioxide (CO2). Carbon dioxide is a colourless, odourless gas. It is released when fossil fuels are burned. Burning fossil fuels releases carbon dioxide into the atmosphere. The carbon in the carbon dioxide was stored for millions of years under the ground in the form of hydrocarbons.  

Methane is produced by the breakdown or decay of organic material and can be introduced into the atmosphere by either natural processes – such as the decay of plant material in wetlands, the seepage of gas from underground deposits or the digestion of food by cattle – or human activities – such as oil and gas ...After carbon dioxide, the next most abundant greenhouse gas is methane (CH4). Although carbon dioxide is much more abundant in the atmosphere than methane, methane traps roughly 30 times more heat than carbon dioxide. This makes methane an important gas to keep an eye on.                

  Cave man appearing    Around 600 kya, (Kya is a term used when referring to an indistinguishable time and is also used as a unit of time to denote length of time before the present) .Europe was invaded by large-brained hominins using Acheulean stone tools (1, 2). They were probably African immigrants, because similar fossils and tools occur earlier in Africa. They have been called archaic Homo sapiens, Homo heidelbergensis, and early Neanderthals, yet they remain mysterious. They may have been ancestors of Neanderthals and modern humans (3), or ancestors of Neanderthals only (4, 5), or an evolutionary dead end. According to this last hypothesis, they were replaced later in the Middle Pleistocene by a wave of African immigrants that separated Neanderthals from modern humans and introduced the Levallois stone tool tradition to Europe (6, 7).            

                                                                                                                                                                     

                         Mammoth Hunters during Ice Age

 Fresh water freezes at 32 degrees Fahrenheit but seawater freezes at about 28.4 degrees Fahrenheit , because of the salt in it. When seawater freezes, however, the ice contains very little salt because only the water part freezes.

To think,  the center of earth's  temperature of the inner core is far above the melting point of iron.  However, unlike the outer core, the inner core is not liquid or even molten. The inner core's intense pressure—the entire rest of the planet and its atmosphere—prevents the iron from melting.  Iron, out of the ground, melts at around 1510 degrees C (2750°F). Steel often melts at around 1370 degrees C (2500°F). The Earth is divided into three main layers. The dense, hot inner core (yellow), the molten outer core (orange), the mantle (red), and the thin crust (brown), which supports all life in the known universe.

How is it that lava, when spurting out of a volcano, looks like melted material?  Most rocks have melting points higher than 700℃. Lava is between 700℃ and 1200℃ when it erupts but starts to cool as it slides down the side of the volcano. The air and the ground help cool it down. You only need 100℃ or 212 F to boil water, so this is very, very hot.

So by the time it’s out of the volcano, lava is generally not quite hot enough to melt the rocks it flows over.

But lava flows can set fire to grass, bushes, and trees. And sometimes if houses are in the way, the lava flow will set fire to the wood that is in the houses. All that is left of the house is ash.           Then there's 2 movies depicting ancient days.                                        

One Million B.C. is a 1940 American fantasy film produced by Hal Roach Studios and released by United Artists. It is also known by the titles Cave Man, Man and His Mate and Tumak.                                                             

The film stars Victor Mature as protagonist Tumak, a young caveman who strives to unite the uncivilized Rock Tribe and the peaceful Shell Tribe, Carole Landis as Loana, daughter of the Shell Tribe chief and Tumak's love interest, and Lon Chaney Jr. as Tumak's stern father and leader of the Rock Tribe. Chaney's billing differs from that of his home studio Universal Pictures in that Hal Roach elected to retain the "Jr." instead of billing him under his father's name, possibly because Roach was co-directing the film with his own son Hal Roach Jr.

The film was a popular success and was nominated for two Academy Awards for its special effects and musical score.

I'm 88 and remember seeing this movie, scared to death as they show the earth opening up during an earthquake and a mother and child falling into it.  It was realistic and horrid to this small little girl.  I've freaked-out during an earthquake ever since.  

      10,000 BC is a 2008 American action-adventure film directed by Roland Emmerich, starring Steven Strait and Camilla Belle. The film is set in the prehistoric era and depicts the journeys of a prehistoric tribe of mammoth hunters. The world premiere was held on February 10, 2008, at Sony Center on Potsdamer Platz in Berlin.  Circa 10,000 BC, a hunter-gatherer tribe called the Yagahl live in the Ural Mountains and survive by hunting woolly mammoths. The tribe is led by a hunter who has killed a mammoth single-handedly and earned the White Spear, and venerate Old Mother, an elderly woman with shamanistic powers. The film was a box office hit, but consistently regarded by professional critics as Emmerich's worst film, as well as one of the worst films of 2008.                                                

In the Paleolithic period (roughly 2.5 million years ago to 10,000 B.C.), early humans lived in caves or simple huts or tepees and were hunters and gatherers. They used basic stone and bone tools, as well as crude stone axes, for hunting birds and wild animals.

How far back is 10,000 BC?  Well, King David in the bible ruled from 1010 to 970 BCE.  Does that help?  1010 BCE was 3,033 years ago.  The movie was about 9,000 years before King David was a king.  This timeline of prehistory covers the time from the appearance of Homo sapiens 315,000 years ago in Africa to the invention of writing, over 5,000 years ago, with the earliest records going back to 3,200 BC. Prehistory covers the time from the Paleolithic (Old Stone Age) to the very beginnings of ancient history.

Jean Auel has written books worth reading.  Jean Marie Auel (/aʊl/; née Untinen; born February 18, 1936) is an American writer who wrote the Earth's Children books, a series of novels set in prehistoric Europe that explores human activities during this time, and touches on the interactions of Cro-Magnon people with Neanderthals. Her books have sold more than 45 million copies worldwide. She attended University of Portland being a Portland girl. While a student, she joined Mensa and worked at Tektronix as a clerk (1965–1966), a circuit-board designer (1966–1973), a technical writer (1973–1974), and a credit manager (1974–1976). She earned an MBA from the University of Portland in 1976. She received honorary degrees from her alma mater, Pacific University, Portland State University, etc. In 1977, Auel began extensive library research of the Ice Age for her first book. She joined a survival class to learn how to construct an ice cave, and learned primitive methods of making fire, tanning leather, and knapping stone from the aboriginal skills expert Jim Riggs. 

Resource:

Good books to read are: by Jean M. Auel (Earth's Children series) 

the Clan of the Cave Bear,

The Mammoth Hunters,

The Shelters of Stone

The Plains of Passage

The Land of Painted Caves

The Valley of Horses

https://www.pnas.org/doi/10.1073/pnas.1706426114

https://geology.utah.gov/map-pub/survey-notes/glad-you-asked/ice-ages-what-are-they-and-what-causes-them/#:~:text=At%20least%20five%20major%20ice,in%20an%20ice%20age!).

https://education.jlab.org/qa/meltingpoint_01.html#:~:text=Iron%2C%20out%20of%20the%20ground,C%20(2500%C2%B0F).

https://oceanservice.noaa.gov/facts/oceanfreeze.html#:~:text=Fresh%20water%20freezes%20at%2032,only%20the%20water%20part%20freezes.

https://theconversation.com/curious-kids-why-doesnt-lava-melt-the-side-of-the-volcano-90683