New Timeline of Life on Earth

Evidence of ancient life on Earth is tough to find. But some scientists think they’ve found some of the oldest. Previously, it was estimated that the oldest biomolecules known by man were about 2.5 billion years old. However, the oldest biosignatures are actually 3.3 billion years old.

The authors of a new study claim to have deepened our understanding of Earth’s earliest biosphere and, at the same time, will provide new avenues for potentially finding past life on Mars and other planets.

The team studied the world’s oldest rocks. High-resolution chemical analysis broke down organic and inorganic materials from the rocks, producing molecular fragments. An artificial intelligence system was used to recognize the chemical fingerprints left behind by life. The system learned how to do this by analyzing 406 samples of plants, animals, fossils, and meteorites. The AI can distinguish between biological and non-biological material with over 90% accuracy.

The biggest splash was the detection of photosynthesis in 2.5-billion-years-old rocks. It seems that ancient life leaves more than fossils. It also leaves chemical echoes, which the AI can now reliably interpret. Computers have been trained to recognize any molecular trace left by living organisms, even after the biomolecules were gone.

Earth’s earliest life hasn’t left many traces behind, since ancient cells have been swallowed by Earth’s crust. This has pretty much obliterated clues about the origins of life. But the researchers hope ancient rocks can reveal glimpses of that history.

Most organic molecules from the past have been altered by geological processes but are still useful to study. And this process isn’t restricted to Earth-formed rocks, either. It could help guide the search for life on other planets.

 

https://www.msn.com/en-us/news/technology/scientists-just-upended-the-timeline-of-life-on-earth/ar-AA1RczqG?ocid=hpmsn&cvid=6927488fa04e4b7fb9572d1e90909288&ei=71

Why This Ancient Civilization Vanished

The ancient Indus River Valley civilization had gridded streets, multistory homes, flush toilets, and bustling shops. It traded gold, precious stones, and bronze carts with other areas along the region’s waterways. Some people carved human figurines and others made toys of clay. Crops included wheat, barley, and cotton. Tools were made to bring water from nearby rivers for crops.

The valley is largely located in Pakistan and northwest India. It hosted one of the most advanced societies at the time, rivaling Mesopotamia and ancient Egypt. And then it disappeared.

Scientists have been looking at the environmental conditions in an attempt to explain the downfall of Harappa, one of the valley’s largest cities. Using paleoclimate data and computer models, they re-created the climate during the civilization’s existence, which was between 3000 and 1000 BC. During that time, four intense droughts dried up waterways and soils. This probably caused the Harappan residents to relocate frequently.

Harappa’s decline was partially caused by repeated, long, and intensifying rivers droughts that lasted centuries. It is thought that if there is less food and a weak government, such droughts can push a civilization over the brink. Despite the persistent droughts, this civilization lasted a long time.

Over 2,000 years, Harappan settlements became more concentrated closer to water.

Scientists determined that vigorous monsoons across the region created much wetter conditions than today. That was between 3000 and 2475 BC. But then drier conditions and increased temperatures came in. And droughts.

There were four droughts—each lasting more than 85 years—between 2425 and 1400 BC. The third drought was the worst and it peaked around 1733 BC. It lasted for 164 years and affected most of the region.

The rainfall changes meant lakes and shallow waterbodies shrank, river flow decreased, and the soil dried up. Lower rivers meant that trade boats and barges could only move at certain times. Agriculture also became tougher in areas away from waterways.

This pushed people to move, which may have contributed to the society’s decline.

 

https://www.msn.com/en-us/news/world/scientists-may-have-solved-why-this-ancient-advanced-civilization-vanished/ar-AA1RhqRG?ocid=hpmsn&cvid=6928fae6b3a04bd585a20b944d8846b3&ei=14