These and other missions on the horizon will face the same obstacle that has plagued scientists since they first attempted to search for signs of Martian biology with the Viking landers in the 1970s: There is no definitive signature of life.
That might be about to change. In 2021, a team led by Lee Cronin of the University of Glasgow in Scotland and Sara Walker of Arizona State University proposed a very general way to identify molecules made by living systems—even those using unfamiliar chemistries. Their method, they said, simply assumes that alien life forms will produce molecules with a chemical complexity similar to that of life on Earth.
Called assembly theory, the idea underpinning the pair’s strategy has even grander aims. As laid out in a recentseries of publications, it attempts to explain why apparently unlikely things, such as you and me, even exist at all. And it seeks that explanation not, in the usual manner of physics, in timeless physical laws, but in a process that imbues objects with histories and memories of what came before them. It even seeks to answer a question that has perplexed scientists and philosophers for millennia: What is life, anyway?
The origin and early evolution of life is generally studied under two different paradigms: bottom up and top down. Prebiotic chemistry and early Earth geochemistry allow researchers to explore possible origin of life scenarios. But for these “bottom–up” approaches, even successful experiments only amount to a proof of principle. On the other hand, “top–down” research on early evolutionary history is able to provide a historical account about ancient organisms, but is unable to investigate stages that occurred during and just after the origin of life. Here, we consider ancient electron transport chains (ETCs) as a potential bridge between early evolutionary history and a protocellular stage that preceded it. Current phylogenetic evidence suggests that ancestors of several extant ETC components were present at least as late as the last universal common ancestor of life. In addition, recent experiments have shown that some aspects of modern ETCs can be replicated by minerals, protocells, or organic cofactors in the absence of biological proteins. Here, we discuss the diversity of ETCs and other forms of chemiosmotic energy conservation, describe current work on the early evolution of membrane bioenergetics, and advocate for several lines of research to enhance this understanding by pairing top–down and bottom–up approaches.
In this “Ask Me Anything” (AMA) episode, Peter delves into the realm of genetics, unraveling its connection to disease and emphasizing the value of understanding one’s genetic risks. He elucidates essential background knowledge on genetics before delving into the myriad reasons why individuals might consider genetic testing. Peter differentiates scenarios where genetic testing provides genuine insights from those where it may not be as useful. From there, Peter explores a comprehensive comparison of commercial direct-to-consumer genetic tests, providing insights on interpreting results and identifying the standout options for gaining insights into personal health.
In this sneak peek, we discuss: 00:00 — Intro. 02:09 — Defining the term “genetics” and why it’s important. 04:03 — What is DNA, and how does it impact our biology and traits? 07:13 — How are genetics passed down from parent to child? 11:44 — How much do genes vary across individuals? 16:22 — Which traits are determined by genetics versus experience or environmental factors? 22:30 — Reasons for genetic testing.
In the full episode, we also discuss: –What exactly is being measured by a genetic test?; –Testing for monogenic disorders; –Understanding polygenic risk; –Is genetic testing more important for someone who doesn’t know their family history?; –What does it mean to be positive for a particular variant?; –What does it mean to be negative for a particular variant?; –How does someone get genetic testing through their healthcare provider, and how are these tests performed?; –The financial cost of various genetic tests; –Could having a risk allele for a disease result in an increase in one’s insurance premium?; –Other risks associated with genetic testing; –How do commercial, direct-to-consumer genetic tests compare to the information one might receive from clinical genetic testing?; –Are certain direct-to-consumer tests better than others?; –How long until whole genome sequencing becomes genuinely useful?; –How useful are personalized dietary recommendations based on genetics?; –Final thoughts and advice regarding genetic testing; and. –More.
——- About:
The Peter Attia Drive is a deep-dive podcast focusing on maximizing longevity, and all that goes into that from physical to cognitive to emotional health. With over 70 million episodes downloaded, it features topics including exercise, nutritional biochemistry, cardiovascular disease, Alzheimer’s disease, cancer, mental health, and much more.
Findings at Fermilab show discrepancy between theory and experiment, which may lead to new physics beyond the Standard Model.
Physicists now have a brand-new measurement of a property of the muon called the anomalous magnetic moment that improves the precision of their previous result by a factor of 2.
An international collaboration of scientists working on the Muon g-2 experiment at the U.S. Department of Energy’s Fermi National Accelerator Laboratory announced the much-anticipated updated measurement on August 10. This new value bolsters the first result they announced in April 2021, and sets up a showdown between theory and experiment over 20 years in the making.
The innovative tweak will allow scientists to directly observe molecular behavior over a much longer period, opening a window onto pivotal biological processes like cell division.
“The living cell is a busy place with proteins bustling here and there,” explains University of Michigan biomedical engineer Guangjie Cui. “Our superresolution is very attractive for viewing these dynamic activities.”
Physicist Michio Kaku explains how quantum computing works and why it will outpace artificial intelligence as the next frontier in technological breakthroughs. #CNN #News
Black holes seem to get all the attention. But what about their mirror twins, white holes? Do they exist? And, if so, where are they?
To understand the nature of white holes, first we have to examine the much more familiar black holes. Black holes are regions of complete gravitational collapse, where gravity has overwhelmed all other forces in the universe and compressed a clump of material all the way down to an infinitely tiny point known as a singularity. Surrounding that singularity is an event horizon, which is not a physical, solid boundary, but simply the border around a singularity where the gravity is so strong that nothing, not even light, can escape.
While the global technology community has been fixated on artificial intelligence (AI) software since the launch of OpenAI’s ChatGPT in November, the Chinese-made GR-1 — said to be capable of walking on two legs at a speed of 5km an hour while carrying a 50kg load — reminded people of the potential of bipedal robots, which are being pursued by global companies from Tesla to Xiaomi.
For Fourier, a Shanghai-based start-up, GR-1 was an unlikely triumph.
In science, the simplest explanations often hold the most truth, a concept known as “Occam’s Razor.” This principle has shaped scientific thought for centuries, but when dealing with abstract ideas, how do we evaluate them?
In a new paper, philosophers from UC Santa Barbara and UC Irvine discuss how to weigh the complexity of scientific theories by comparing their underlying mathematics. They aim to characterize the amount of structure a theory has using symmetry — or the aspects of an object that remain the same when other changes are made.
After much discussion, the authors ultimately doubt that symmetry will provide the framework they need. However, they do uncover why it’s such an excellent guide for understanding structure. Their paper appears in the journal Synthese.
