While urban greening can help mitigate extreme heat, such spaces are not distributed equitablyIt has been a summer of heatwaves in western Europe, with record highs of 46C (115F) in Spain and Portugal.An estimated 2,300 people died of heat-related causes across 12 European cities in June, according to a rapid scientific analysis, with two-thirds of those deaths linked to climate breakdown, which has made heatwaves more severe. Continue reading...

It's a mystery that has long puzzled researchers. Freud called the phenomenon infantile amnesia, and for many years scientists have wondered whether it's a result of failure to create memories or just a failure to retrieve them.In this episode from March 2025, Ian Sample speaks to Nick Turk-Browne, a professor of psychology at Yale University, whose research appears to point to an answerWhy can't we remember our lives as babies or toddlers?Support the Guardian: theguardian.com/sciencepod Continue reading...

Large study suggests people's genetics could tip the balance' on whether they would develop the illnessScientists have found the first robust evidence that people's genes affect their chances of developing myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS), a mysterious and debilitating illness that has been neglected and dismissed for decades by many in the medical community.Early findings from the world's largest study into the genetics of the condition pinpointed eight regions of the human genome that were substantially different in people with an ME/CFS diagnosis compared to those without the illness. Continue reading...

Site director says a kind of camp, a favela' was founded in the ruins of city destroyed in AD79Archaeologists have discovered new evidence pointing to the reoccupation of Pompeii after the AD79 eruption of Mount Vesuvius that left the city in ruins.Despite the massive destruction suffered by Pompeii, an ancient Roman city home to more than 20,000 people before the eruption, some survivors who could not afford to start a new life elsewhere are believed to have returned to live in the devastated area. Continue reading...

Winner of Project Hyperion design contest envisions polyamorous people thriving onboard cigar-shaped craftSpaceships modelled on jellyfish, 3D-printed homes, polyamorous relationships and vegetarian diets are among the ways in which experts have envisaged making interstellar travel feasible.The ideas from scientists, engineers, architects and social theorists came in response to a global competition to develop plans for generation ships", self-sustaining crafts capable of supporting up to 1,500 people on a 250-year journey to a habitable planet. Continue reading...

Agency to end 22 federal contracts, questioning safety of technology credited with helping end Covid pandemicThe US Department of Health and Human Services said on Tuesday it would terminate 22 federal contracts for mRNA-based vaccines, questioning the safety of a technology credited with helping end the Covid pandemic and saving millions of lives.The unit, Biomedical Advanced Research and Development Authority, helps companies develop medical supplies to address public health threats, and had provided billions of dollars for development of vaccines during the Covid-19 pandemic. Continue reading...

Even if we don't develop long sticky tongues and a taste for termites, we can still learn a lot from these remarkable creaturesWho doesn't love an anteater? I mean, apart from ants, obviously. With their long snouts and even longer sticky tongues, they trundle around, slurping up insects like milkshakes. They have handsome, bushy tails, which they wrap around themselves at night like a blanket. And they're excellent parents. Giant anteater mothers allow their young to cling to their backs, rucksack-style, for periods of up to a year.Indeed, the surrealist artist Salvador Dali was so taken with the giant anteater that he once took one for a walk through the streets of Paris. And before you ask, no, this wasn't a cheese dream. There is photographic evidence.Helen Pilcher is a science writer and the author of Bring Back the King: The New Science of De-Extinction and Life Changing: How Humans are Altering Life on Earth Continue reading...

Too much exposure to the sun has traditionally been seen as a danger. Now claims that sunscreen is toxic flood the internet. What does the science say?It's summertime in the UK and social media is awash with influencers airing their concerns about sunscreen. Among them is reality TV star Sam Faiers from The Only Way Is Essex, who believes sunscreen is full of toxic ingredients". None of her family wore sunscreen, she said, adding that her children had built up a really good tolerance" to the sun. Some of the claims appear to be fuelled by a US doctor who told his followers: Be careful what you smear on yourself and your children." Here we look at the science behind sunscreen and sun exposure. Continue reading...

More than 100 million novel entity' chemicals are in circulation, with health impact not widely recognisedChemical pollution is a threat to the thriving of humans and nature of a similar order as climate change" but decades behind global heating in terms of public awareness and action, a report has warned.The industrial economy has created more than 100 million novel entities", or chemicals not found in nature, with somewhere between 40,000 and 350,000 in commercial use and production, the report says. But the environmental and human health effects of this widespread contamination of the biosphere are not widely appreciated, in spite of a growing body of evidence linking chemical toxicity with effects ranging from ADHD to infertility to cancer. Continue reading...

Risks of a wave are compounded by new vaccine restrictions from the Trump administrationCovid is on the rise again in the US, as children begin returning to school and as officials plan to restrict booster shots.While cases are increasing less quickly than at the start of other surges, it is too soon to tell how big the current late-summer wave could get - and with highly varied immune responses from prior infections and vaccinations, it is difficult to know how severe illness could be, experts said. Continue reading...

After 90% loss of global sunflower sea star population in 10 years, researchers hope decline can now be tackledA decade after the onset of a sea star wasting disease (SSWD) epidemic considered the largest ever documented in the wild, researchers have identified the microbial culprit responsible: a strain of the bacterium Vibrio pectenicida.In 10 years, the bacterium has ravaged sunflower sea stars (Pycnopodia helianthoides), a large sea star or starfish, along the western coast of North America, with a loss of 5.8 billion since 2013 - or 90% of the total global population. The sunflower sea star is on the International Union for Conservation of Nature's red list of critically endangered species. Continue reading...

Recently, a group of world-leading scientists called for a halt on research to create mirror life' microbes amid concerns that the synthetic organisms would present an unprecedented risk' to life on Earth. Ian Sample tells Madeleine Finlay about why this work initially seemed exciting for scientists and what the risks of it continuing could be. Kate Adamala, assistant professor of genetics, cell biology and development at the University of Minnesota, describes what made her change her mind about pursuing her own research on mirror cellsUnprecedented risk' to life on Earth: scientists call for halt on mirror life' microbe researchSupport the Guardian: theguardian.com/sciencepod Continue reading...

Solutions for todays puzzles plus a gallery of readers' designsEarlier today I wrote about ambigrams, a type of writing that is designed to be read in more than one way. Typically, an ambigram is a word or phrase that has left-right mirror symmetry, or reads the same upside down. (To read the article click here.)I set the following challenge - scroll down to see designs by ambigram author (and public intellectual) Douglas Hofstadter and by readers of this column. Continue reading...

Dieters in trial lost twice as much weight when avoiding ultra-processed ready meals with as much nutritionPeople lose more weight if they cook minimally processed food from scratch than if they eat ultra-processed and ready-made foods, according to the first study to establish a clear link between ultra-processed foods (UPFs) and weight.Trial participants were given one of two diets with the same nutritional profile for eight weeks. One diet was made up of UPFs while the other comprised minimally processed foods. Continue reading...

A pun, a puzzle and a work of artUPDATE: Read the solutions hereDouglas Hofstadter is probably best known as the author of Godel, Escher Bach, a classic of popular science writing published in 1979.In 1983, he coined the word ambigram", meaning a piece of text that can be read in more than one way, an art form pioneered in the 1970s by the typographers Scott Kim and John Langdon. Typically, an ambigram is a word or phrase that has left-right mirror symmetry, or reads the same upside down. Continue reading...

The planet will be shining brightly and visible in even the most light-polluted urban environmentsAugust is another bright sky month in the northern hemisphere so we're having to look for late night and early morning events featuring bright celestial objects. Luckily, Venus has us covered. The planet reaches its highest altitude in the morning sky this month, rising more than three hours earlier than the Sun at mid-northern latitudes and shining brilliantly in the eastern sky.This week, the planet is located in the constellation of Gemini, the Twins. It will be unmistakably bright, shining with an apparent magnitude of -4, making it brighter than everything else in the sky, except the Sun and the moon. This will mean it is visible even from the most light-polluted urban environments. Continue reading...

An experienced clinician in prosthetics, Jim Ashworth-Beaumont found himself the perfect guinea pig for a radical new option for amputeesWhen the air ambulance brought Jim Ashworth-Beaumont to King's College hospital in south-east London, nobody thought he had a hope. He had been cycling home when a lorry driver failed to spot him alongside his trailer while turning left after a set of traffic lights. The vehicle's wheels opened his torso like a sardine tin, puncturing his lungs and splitting his liver in two. They also tore off his right arm. Weeks after the accident, in July 2020, Ashworth-Beaumont would see a photo of the severed limb taken by a doctor while it lay beside him in hospital. He had asked to see the picture and says it helped him come to terms with his loss. My hand didn't look too bad," he says. It was as if it was waving goodbye to me."Ashworth-Beaumont, a super-fit and sunny former Royal Marine from Edinburgh, would go on to spend six weeks in an induced coma as surgeons raced to repair his crushed body. But as he lay on the road, waiting for the paramedics, his only thoughts were that he was dying. He did not have the wherewithal to consider the irony of his predicament. Continue reading...

Jaime Slaughter-Acey's study addresses the high rates of maternal mortality among Black women in the US. Trump's NIH funding cuts threaten her years-long researchJaime Slaughter-Acey was in a state of shock and anger when she learned that her National Institutes of Health (NIH)-funded study on birth outcomes in Black families was cancelled this spring. The University of North Carolina at Chapel Hill associate professor in epidemiology said that she felt like the rug was pulled out from under us" when the university called her to share the news. The termination notice said that the study no longer met the agency's priorities and didn't promise to increase life expectancy.It was heartbreaking," Slaughter-Acey told the Guardian, and honestly, infuriating given the high rates of maternal and infant mortality in this country." Continue reading...

Experts say the report being used to justify the mass rollback of climate regulations has many claims based on long-debunked researchA new Trump administration report which attempts to justify a mass rollback of environmental regulations is chock-full of climate misinformation, experts say.On Tuesday, the Environmental Protection Agency (EPA) announced a proposal to undo the 2009 endangerment finding", which allows the agency to limit planet-heating pollution from cars and trucks, power plants and other industrial sources. Hours later, the Department of Energy (DOE) published a 150-page report defending the proposal, claiming scientific concern about the climate crisis is overblown. Continue reading...

Prof Michele Dougherty, first woman to hold position, is upbeat about role of private sector in space explorationThe Royal Society was right to keep Elon Musk as a fellow, the UK's new astronomer royal has said, adding there was a benefit to the private sector playing a role in space exploration.Speaking to the Guardian after becoming the first woman to hold the 350-year-old position, the planetary scientist Prof Michele Dougherty said she had not been involved in the meetings around Musk's fellowship, but that she supported the academy's stance. Continue reading...

Hybridisation event took place about 9 million years ago, helping to spark the emergence of a new organ'When it comes to the senses, there could not be a greater difference between Friday night chips and juicy Mediterranean tomatoes.However, scientists have discovered that these two foods are not so far from each other after all. Landmark research has found the potato evolved from a tomato ancestor nearly 9 million years ago. Continue reading...

Parents of boy born in Ohio, US, used adopted' IVF embryo that had been stored away for more than 30 yearsThe world's oldest baby" has been born in the US from an embryo that was frozen in 1994, it has been reported.Thaddeus Daniel Pierce was born on 26 July in Ohio to Lindsey and Tim Pierce, using an adopted" embryo from Linda Archerd, 62, from more than 30 years ago. Continue reading...

The 2017 flash, which stretched from east Texas to near Kansas City, beat the previous record by almost 50 milesA 515-mile (829km) lightning flash has set a new record as the longest ever identified.The World Meteorological Organization (WMO) confirmed the new world record for the flash registered on 22 October 2017 over the Great Plains in the US. It stretched from east Texas to near Kansas City, Missouri, roughly the distance between Paris and Venice. Continue reading...

In this episode from January 2025, Ian Sample speaks to Keon West, a professor of social psychology at the University of London, whose new book explores what science can reveal about racism, the inventive methods scientists have used to study it and the scientifically proven ways of tackling racism and discriminationOrder The Science of Racism by Keon West from the Guardian bookshopSupport the Guardian: theguardian.com/sciencepod Continue reading...

Race against time to study HMS Northumberland as shifting sands expose part of well-preserved wreck off KentThe English warship HMS Northumberland was built in 1679 as part of a wave of naval modernisation overseen by Samuel Pepys, a decade after he had stopped writing his celebrated diary and gone on to become the Royal Navy's most senior administrator.Twenty-four years later, after the ship had taken part in many of the major naval battles of its day, it was at the bottom of the North Sea, a victim of the Great Storm of 1703, one of the deadliest weather disasters in British history. Continue reading...

Physicist who worked on Nasa Cassini mission absolutely delighted' after being awarded 350-year-old titleA planetary scientist whose research revealed the possibility of extraterrestrial life on one of Saturn's moons has been made the first female astronomer royal.Prof Michele Dougherty, a leading space physicist who was a researcher for the Nasa Cassini mission, has been awarded the 350-year-old honorary title. In 2021, Catherine Heymans, a professor of astrophysics at the University of Edinburgh, became the first female astronomer royal for Scotland, a post established in 1834. Continue reading...

First response should be chest compressions rather than preventing tongue swallowing', researchers suggestIt is the simple life-saving sequence taught in many a first aid lesson: when someone collapses, first check their airways, then breathing and finally circulation before starting chest compressions if needed.But experts have warned this approach to CPR could be increasing the risk of death for athletes experiencing a cardiac arrest. Continue reading...

While Gilmour Space's Eris rocket lasted only 14 seconds in the air above Bowen, nascent Australian space industry says failed orbit attempt is a launchpad for future success

Although the trends can be hard to perceive, we are making incredible progress on global poverty, health, longevity and climate changeDon't fret the future.A lot of people do, and for powerful reasons - we are facing enormous challenges unprecedented in human history, from climate change and nuclear war to engineered pandemics and malicious artificial intelligence. A 2017 survey showed that nearly four in 10 Americans think that climate change alone has a good chance of triggering humanity's extinction. But we seem largely blind to the many profound reasons for hope - and it's not entirely our fault. Continue reading...

The Southern Delta Aquariids and the Alpha Capricornids showers are best viewed on Tuesday or Wednesday between 11pm and dawnStargazers and night owls in Australia will be in prime position to catch a glimpse of two spectacular meteor showers this week as they pass through our atmosphere.The good news is that you won't need a telescope or a pair of binoculars to see the Southern Delta Aquariids and the Alpha Capricornids showers - just your own eyes. Continue reading...

In 2024, the Oxford English Dictionary announced its word of the year was brain rot'. The term relates to the supposedly negative effects of consuming social media content, but it struck a chord more widely with many who feel they don't have the mental capacity they once had.Gloria Mark, a professor of informatics at the University of California, Irvine, has been studying our waning attention spans for 20 years. In this episode from January 2025, she tells Madeleine Finlay why she believes our powers of concentration are not beyond rescue, and reveals her top tips for finding focusIs modern life ruining our powers of concentration?Support the Guardian: theguardian.com/sciencepod Continue reading...

Lancet Commission says three in five cases preventable with action on obesity, alcohol and hepatitisThree in five liver cancer cases globally could be prevented by reducing obesity and alcohol consumption and increasing uptake of the hepatitis vaccine, a study has found.

Diagnosed with impaired depth perception as a child, Hampton has learned to read subtle cues from penalty takers and embrace goalie tacticsHannah Hampton had already saved one penalty in the shootout against Spain at Euro 2025 when Aitana Bonmati, the back-to-back winner of the women's Ballon d'Or, placed the ball on the spot and stepped back, taking a moment before the strike. Bonmati thumped the ball hard and left, but Hampton was there, arms outstretched, to block the shot with both hands.Better pens than the last time, let's be honest!" Hampton said after the match, a reference to the more painful shootout against Sweden in the quarter-final that went to sudden death before England prevailed. Hampton saved two penalties that time, too. Continue reading...

Scientists use VR headsets to see how participants react to faces of people showing signs of viral infectionsWhether it's the person brandishing a tissue on the train or the child with the telltale signs of chickenpox, the threat of an infection can be enough for us to beat a retreat.Now researchers using virtual reality avatars have shown that the mere sight of a potentially contagious person is enough to mobilise our immune system too. Continue reading...

The full constellation never rises above the UK horizon, but its most recognisable part, the teapot, will be visibleIt's a good time of year to track down the summer constellation of Sagittarius, the archer, who is usually depicted as a centaur drawing a bow.The chart shows the view looking south from London at 23:00 BST on 28 July, when the most recognisable portion of the constellation will be visible. Often called the teapot because of its distinctive shape, it fits into the larger constellation. The teapot's spout, as represented by the star Alnasl, depicts the arrow's sharp head in the full constellation. The lid and handle represent the upper body and outstretched arms. Continue reading...

Skulls were collected from all over the world because of some academics' fascination with phrenology, the discredited belief that skull shape denoted intelligenceHundreds of skulls are neatly and closely placed, cheekbone to cheekbone, in tall, mahogany-framed glass cabinets. Most carry faded, peeling labels, some bear painted catalogue numbers; one has gold teeth; and the occasional one still carries its skin tissue. This is the University of Edinburgh's skull room".Many were voluntarily donated to the university; others came from executed Scottish murderers; some Indigenous people's skulls were brought to Scotland by military officers on expeditions or conquest missions. Several hundred were collected by supporters of the racist science of phrenology - the discredited belief that skull shape denoted intelligence and character. Continue reading...

We need to reckon honestly with science's past and present to avoid a grim futureScience is in crisis. Funding infrastructures for both basic and applied research are being systematically decimated, while in places of great power, science's influence on decision making is waning. Long-term and far-reaching studies are being shuttered, and thousands of scientists' livelihoods are uncertain, to say nothing of the incalculable casualties resulting from the abrupt removal of life-saving medical and environmental interventions. Understandably, the scientific community is working hard to weather this storm and restore funding to whatever extent possible.In times like these, it may be tempting to settle for the status quo of six months ago, wanting everything simply to go back to what it was (no doubt an improvement for science, compared with the present). But equally, such moments of crisis offer an opportunity to rebuild differently. As Arundhati Roy wrote about Covid-19 in April 2020, Historically, pandemics have forced humans to break with the past and imagine their world anew. This one is no different. It is a portal, a gateway between one world and the next." What could science look like, and what good could science bring, if we moved through the portal of the present moment into a different world?Ambika Kamath is trained as a behavioral ecologist and evolutionary biologist. She lives, works and grows community in Oakland, California, on Ohlone land

The urge to avoid music that brings up trauma from the past is powerful, but it may be better to actively engage'When Bonnie hears the opening bars of the Verve's Bitter Sweet Symphony, she is transported back to 1997. But it isn't a joyful memory that comes to mind; it is the painful recollection of driving home from school and seeing the sheriff changing a lock on her house.Then a teenager, Bonnie and her family were about to be evicted. And the Verve's song was everywhere. Continue reading...

Researchers believe humans' closest relatives may have stored meat from their kills for months before eating itFor hungry Neanderthals, there was more on the menu than wild mammals, roasted pigeon, seafood and plants. Chemical signatures in the ancient bones point to a nutritious and somewhat inevitable side dish: handfuls of fresh maggots.The theory from US researchers undermines previous thinking that Neanderthals were hypercarnivores" who stood at the top of the food chain with cave lions, sabre-toothed tigers and other beasts that consumed impressive quantities of meat. Continue reading...

Canadian data analysis underscores importance of support during and after pregnancy, researchers saySurrogates have a greater chance of being newly diagnosed with a mental illness during and after pregnancy than women who carry their own offspring, researchers have found.In addition, regardless of how they conceived, women with a previous record of mental illness were found to have a higher risk of being diagnosed with such conditions during and after pregnancy than those without. Continue reading...

SpaceX's powerful internet system suffers rare disruption in one of its biggest international outagesSpaceX's Starlink suffered one of its biggest international outages on Thursday when an internal software failure knocked tens of thousands of users offline, a rare disruption for Elon Musk's powerful satellite internet system.Users in the US and Europe began experiencing the outage at around 3pm EDT (1900 GMT), according to Downdetector, a crowdsourced outage tracker that said as many as 61,000 user reports to the site had been made. Continue reading...

Period characteristics can indicate medical conditions and could inform preventive care, study findsMenstrual cycle data should be routinely documented by healthcare professionals and researchers as it can be used as an indicator for other health issues, experts have said.This information - which includes cycle length, regularity, intensity and duration of bleeding - is not routinely collected in healthcare systems or research except when reproductive issues are being assessed. Continue reading...

Workers allege illegal terminations, censorship and collapse of scientific review standardsAlmost 150 workers from the National Science Foundation (NSF) have lambasted Donald Trump's cuts to the agency as politically motivated and legally questionable", joining colleagues at three other federal research agencies in warning that the administration is destroying innovation and sacrificing the US's position as a global scientific leader.The three-page dissent states the actions of the administration collectively amount to the systemic dismantling of a world-renowned scientific agency" and that they have been compelled to act because NSF employees are bound by their oath to uphold the Constitution." Continue reading...

Technology is tricky. That's why we need to think more carefully about risks and follow a more cautious approachToday, so-called techno-optimists fill the ranks of Silicon Valley billionaires. They proclaim a bright future for humanity delivered by the rapid pursuit of technological advances.Of course, these techno-optimists are right that technology and science are unarguably among humanity's greatest assets, and hope for the future. But they go too far, because it is also true that technology always creates new problems even as it solves others - this is also something we've learned through science. As a result, naive faith in technology is a recipe for repeatedly achieving a short-term buzz while also incurring long-term costs. Getting the best out of technology requires a more cautious and balanced approach.Mark Buchanan is a physicist and science writer and the author of Ubiquity and Nexus: Small Worlds and the New Science of Networks Continue reading...

Steve James, from Devon, hits halfway mark in circuit of Great Britain's coast as scientists monitor impact of extreme featThe first fortnight was tough - terrible blisters, a flare of gout that needed a visit to A&E and the rapid realisation that running 200 marathons in 200 days around the coast of Great Britain would not be a walk in the park.But Steve James, a 65-year-old retired banker from Devon, has found his feet, and on Thursday reached the halfway mark - an average of 100 marathons in 100 days. Continue reading...

Scientists are beginning to understand that ageing is not a simply linear process. Instead, recent research appears to show that we age in three accelerated bursts; at about 40, 60 and 80 years old. To find out what might be going on, Ian Sample hears from Prof Michael Snyder, the director of the Center for Genomics and Personalised Medicine at Stanford University School of Medicine, who explains what the drivers of these bursts of ageing could be, and how they might be counteractedScientists find humans age dramatically in two bursts - at 44, then 60Support the Guardian: theguardian.com/sciencepod Continue reading...

Pioneering radio astronomer whose work locating celestial objects led to a greater understanding of the universeSir Francis Graham-Smith, who has died aged 102, was the last of the generation that created modern radio astronomy, the branch of astronomy that studies the universe with radio waves, in the 1940s and 50s. His PhD thesis, on the first Cambridge radio survey, carried out between 1948 and 1950, with reasonably accurate positions for the brightest sources, paved the way to demonstrating that the majority of celestial radio sources are distant galaxies with massive black holes in their nuclei.Following the discovery of pulsars, pulsating radio sources associated with rapidly rotating neutron stars, in 1967 by Antony Hewish, Jocelyn Bell and others, Graham-Smith used the Jodrell Bank Mark I telescope to study pulsars in detail. He and Andrew Lyne wrote the definitive book on the subject, Pulsar Astronomy (1990). Continue reading...

Aeneas program, which predicts where and when Latin texts were made, called transformative' by historiansIn addition to sanitation, medicine, education, wine, public order, irrigation, roads, a freshwater system and public health, the Romans also produced a lot of inscriptions.Making sense of the ancient texts can be a slog for scholars, but a new artificial intelligence tool from Google DeepMind aims to ease the process. Named Aeneas after the mythical Trojan hero, the program predicts where and when inscriptions were made and makes suggestions where words are missing. Continue reading...

Study finds that only 9.5% of fungal biodiversity hotspots fell within existing protected areasThe underground networks of fungi that underpin the planet's ecosystems needs urgent conservation action by politicians, a research organisation has said.Scientists from the Society for the Protection of Underground Networks (Spun) have created the first high-resolution biodiversity maps of Earth's underground mycorrhizal fungal ecosystems. Continue reading...

Researchers believe huge volcanic eruptions, and the absence of plants, turned our planet into one giant snowballIt's hard to believe, but about 700m years ago it's thought that our planet completely froze over with little to no liquid ocean or lakes exposed to the atmosphere, even in the tropics. But what tipped Earth's climate into Snowball Earth" state? A new study suggests a cold climate and massive volcanic eruptions set the scene.The Franklin eruptions - about 720m years ago - spewed out vast amounts of fresh rock, stretching from what is now Alaska, through northern Canada to Greenland. Similarly large eruptions have happened at other times, but this one happened to coincide with an already cold climate. And combined with a lack of plants (they hadn't evolved yet) these eruptions exposed a huge carpet of fresh rock to intense weathering. Continue reading...