A long read introduction to the topic - from We Want to Believe: How Aliens Went Mainstream and Why It Matters
"The search for exoplanets is radically expanding our understanding of the cosmos. “We have learned that the universe is teeming with a fascinating variety of planets, more types than we could have imagined,” writes the astrobiologist Lisa Kaltenegger. But so far, it has found exactly as many extraterrestrials as radio astronomy has: zero. The more we learn about the universe, the more acute the Fermi paradox becomes."
Ultimately, the arguments over quantum mechanics have much bigger stakes: what reality is. The basic problem is that the theory tells us what we can expect to observe if we make measurements of a quantum system such as an atom or an electron. It doesn’t tell us how the world is, only what we’ll see if we look. Quantum uncertainty, the physicist and philosopher Jeffrey Bub of the University of Maryland told me, “doesn’t simply represent ignorance about what is the case, but a new sort of ignorance about something that doesn’t yet have a truth value, something that simply isn’t one way or the other before we measure.”
Asteroids would’ve supplied the necessary raw materials, heat, and geologic plumbing to circulate prebiotic matter while also creating freshwater crater lakes conducive to supporting life.
Unlike modern crocodiles, which mostly lurk in rivers and swamps, mekosuchines were an extraordinarily diverse and adaptable group. They filled ecological roles unlike any reptiles alive today. Some species were small and land-dwelling, while others may have hunted in forests rather than waterways.
UNSW paleontologist Professor Michael Archer describes them with a kind of gleeful disbelief. “It’s a bizarre idea,” he says, “but some of them appear to have been terrestrial hunters in the forests.”
Even more astonishing are the “drop crocs”—semi-arboreal species that, according to fossil evidence, may have climbed trees and leapt down on unsuspecting prey below. Archer likens them to reptilian leopards. “They were perhaps hunting like big cats—dropping out of trees on any unsuspecting thing they fancied for dinner,” he says.
Such behavior challenges our assumptions about crocodiles, painting a picture of ancient ecosystems filled with agile, cunning predators unlike anything in Australia today.
Intelligence might be a common evolutionary outcome, considering birds developed high intelligence but took a different path to mammals.
Pigeons, with appropriate training, can discriminate between Picasso and Monet's masterpieces. Ravens can recognize themselves in a mirror. On a Japanese university campus, crows have been known to leave walnuts on a crosswalk and let passing automobiles crack them. Many bird species are very intelligent. However, the "bird brain" frequently receives little respect.
Birds' brains are far more akin to our complicated human organs than previously assumed. For many years, it was thought that the avian brain had restricted function due to the lack of a neocortex. In mammals, the neocortex is the massive, evolutionary recent outer layer of the brain that enables complex cognition and creativity. Yet birds' brain structure at a microscopic level is similar to the neocortex in places, despite its differing shape. While birds and reptiles may not have a neocortex, they do have some of the same neurons. They're just in different places. It turns out that at the cellular level, their brain are structured similarly to the mammalian cortex and doing similar tasks, which explains why many birds exhibit advanced behaviors and talents.
On an evolutionary time scale, high Intelligence may not be particularly unique or unusual. Complex brains and cognitive processes may have developed separately multiple times, as have the circuits and neurons that control them.
It's getting so bad that - according to the World Wildlife Fund - the average person is ingesting up to a credit card's worth of plastic each week. Now a new major scientific review links microplastics to lung and colon cancer.
An interview with the main researcher on ABC radio
“The complex analysis used nearly 6 million galaxies and quasars and lets researchers see up to 11 billion years into the past. With just one year of data, DESI has made the most precise overall measurement of the growth of structure, surpassing previous efforts that took decades to make.” According to Dragan Huterer, professor at the University of Michigan and co-lead of DESI’s group.
The analysis upholds general relativity but hints dark energy may vary over time. The result validates our leading model of the universe. It limits theories of modified gravity like MOND, which have been proposed as alternative ways to explain unexpected observations – including the accelerating expansion of our universe attributed to dark energy.
The standard model of cosmology summarizes our current best knowledge of the Universe. This is based on two well-established pillars of physics. Einstein's General Relativity, which regulates gravitation, and the standard model of particle physics, for all other basic interactions. However, it also relies on three key components — Inflation, Dark matter, and Dark energy that are critical for understanding a wide range of evidence, from the Cosmic Microwave Background to the Universe's Large Scale Structure.
The Dark Energy Spectroscopic Instrument (DESI) measures the effect of dark energy on the universe's expansion. Its completed survey will obtain optical spectra for tens of millions of galaxies and quasars, constructing a 3D map of the nearby universe.
“This is the first time that DESI has looked at the growth of cosmic structure. We’re showing a tremendous new ability to probe modified gravity and improve constraints on dark energy models. And it’s only the tip of the iceberg.”
Additional details on the implications for alternative gravity models in this paper - Ishak et al. (2024), Modified Gravity Constraints from the Full Shape Modeling of Clustering Measurements from DESI 2024 https://arxiv.org/abs/2411.12026
Discoveries about a young ancestor's teeth may shed light on the upward trend in brain size over millennia.
Other explanations
Bipedalism developed long before bigger brains, and the use of tools was widespread in earlier hominid branches. As a result, these causes have been ruled out as the main driving force in brain evolution, despite being essential preconditions. https://efossils.org/book/bipedalism-vs-brain-size
For context that's around this point in Human Evolution
Modern Human life history is distinguished by a prolonged childhood in which mental and somatic development rates diverge. This slow development is crucial for developing high cognitive abilities in our socially complex species.
A slowing childhood in a supportive family and cultural transmission
This individual experienced rapid growth in their first five years, faster than in apes. For example, their wisdom teeth fully emerged at 12 years of age compared to 17-24 today. This rapid growth was unexpected given the age of the fossil and its relationship to modern humans. However, the teeth did have a sequence of growth similar to modern humans. Marcia Ponce de León from the University of Zurich and co-author of the study commented "Milk teeth were used for longer than in the great apes and the children of this early Homo species were dependent on adult support for longer than those of the great apes". She suggests that "This could be the first evolutionary experiment of prolonged childhood".
It is believed that children's development slowed as cultural transmission increased, making the quantity of knowledge conveyed from old to young more crucial. This transmission would have allowed them to make greater use of available resources while developing more sophisticated behaviours, providing them with an evolutionary advantage.
The demands of large brains cause Humans to develop more slowly than our closest animal cousins. Energy directed toward the brain dominates the human body's metabolism early in life, which is possibly one other reason why humans develop at a rate more akin to a reptile than a mammal in early childhood. A five-year-old's brain is a real energy monster. It uses twice as much glucose as a fully grown adult. See https://www.sciencedaily.com/releases/2014/08/140825152558.htm
What does this explain?
However, just identifying some of the forces influencing the brain's evolution does not account for the emergence of more recent advances such as symbolic language. https://www.britannica.com/science/human-evolution/Language-culture-and-lifeways-in-the-Pleistocene Nonetheless, the brain's expansion was an essential precursor to the richness of human culture. Even in this early era of human evolution where children needed to mature rapidly, and life expectancy was low, adult care exerted a protective effect.
Additional Info
A variety of circumstances probably influenced brain development, including contributions from diverse hominid lineages with larger brains that were previously lumped into a single smaller smaller-brained species. Ian Tattersall provides a nuanced discussion of brain size and how it relates to humanities tangled origins in this 2023 article: Endocranial volumes and human evolution, https://pmc.ncbi.nlm.nih.gov/articles/PMC10517302/
https://www.theguardian.com/news/2026/aug/11/the-great-silence-why-havent-we-found-any-aliens-yetOpen linkView original on mander.xyz
