New data suggests the planet may have potentially water-covered surfaces, with a hydrogen-rich atmosphere.
An artist’s concept shows what exoplanet K2-18 b could look like based on science data. Pic: NASA, CSA, ESA, J. Olmsted (STScI)
Carbon dioxide and methane has been detected in the atmosphere of exoplanet K2-18 b – a potentially habitable world more than eight times the size of Earth.
The ground-breaking discovery means K2-18 b may belong to a unique class of exoplanets known as “Hycean” planets, which possess hydrogen-rich atmospheres and potentially water-covered surfaces, making them candidates for life.
The initial insights by NASA’s James Webb Telescope were made possible by observations from NASA’s Hubble Space Telescope.
K2-18 b orbits a cool dwarf star called K2-18 about 120 light years away from Earth – within the constellation Leo – and sits within the habitable zone.
These exoplanets, with sizes between Earth and Neptune, are not found in our solar system, making their characteristics a subject of active debate among scientists.
The idea that K2-18 b could be a Hycean exoplanet is particularly fascinating to scientists, with some experts believing that such planets may offer favourable conditions for life to develop.
Nikku Madhusudhan, an astronomer at the University of Cambridge and lead author of the study, said: “Our findings underscore the importance of considering diverse habitable environments in the search for life elsewhere.
A Bangladesh-born bioengineer and his colleagues at the University of California, San Francisco, have shown that kidney cells in an implantable device survived in a pig for seven days, mimicking several key kidney functions
Representational image File picture
Scientists on Tuesday announced the first successful animal tests with an implantable device that represents a key step towards an artificial kidney that could someday eliminate the need for dialysis in patients with kidney failure.
A Bangladesh-born bioengineer and his colleagues at the University of California, San Francisco, have shown that kidney cells in an implantable device survived in a pig for seven days, mimicking several key kidney functions.
The scientists say their study provides the “first proof of concept” of an implantable bioreactor that sustains human kidney cells in a pig model without being attacked by the recipient’s immune system.
After implantation into pigs, the cells maintained over 90 per cent viability and functionality, the researchers said, describing their work in a paper published on Tuesday in the research journal Nature Communications.
“We are focused on safely replicating the key functions of a kidney,” Shuvo Roy, a professor of bioengineering at the UCSF School of Pharmacy, said in a media release issued by the university. “The bioartificial kidney will make treatment for kidney disease more effective and much more tolerable and comfortable,” said Roy. Their goal is to develop a bioreactor with kidney cells that perform critical functions — such as balancing the body’s fluids and releasing hormones that help regulate blood pressure — and pair it with a device that filters waste from the blood.
Current treatment options for kidney failure include dialysis and transplants. But not enough organs are available for transplants and, the scientists say, dialysis partially replaces kidney cell functions and most dialysis patients develop long-term complications.
Forty years ago, after a few drinks, two astronomers at the University of Tokyo composed a convivial message meant for any forms of extraterrestrial life lurking in the vicinity of a bright star named Altair in the constellation of Aquila, about 16.7 light years from Earth.
This evening, a team from another Japanese university is checking to see if anyone has replied. The team, led by Shinya Narusawa at the University of Hyogo, will deploy an enormous antenna in the mountains of the Nagano prefecture in Japan to scan for any responses.
Artist’s impression of prehistoric animals stuck in natural asphalt seeps. (Cullen Townsend, courtesy of NHMLAC)
Over the past decade, deadly wildfires have become increasingly common because of both human-caused climate change and disruptive land management practices. Southern California, where the three of us live and work, has been hit especially hard.
Southern California also experienced a wave of wildfires 13,000 years ago. These fires permanently transformed the region’s vegetation and contributed to Earth’s largest extinction in more than 60 million years.
As paleontologists, we have a unique perspective on the long-term causes and consequences of environmental changes, both those linked to natural climate fluctuations and those wrought by humans.
In a new study, published in August 2023, we sought to understand changes that were happening in California during the last major extinction event at the end of the Pleistocene, a time period known as the Ice Age. This event wiped out most of Earth’s large mammals between about 10,000 and 50,000 years ago. This was a time marked by dramatic climate upheavals and rapidly spreading human populations.
The last major extinction
Scientists often call the past 66 million years of Earth’s history the Age of Mammals. During this time, our furry relatives took advantage of the extinction of the dinosaurs to become the dominant animals on the planet.
During the Pleistocene, Eurasia and the Americas teemed with enormous beasts like woolly mammoths, giant bears and dire wolves. Two species of camels, three species of ground sloths and five species of large cats roamed what is now Los Angeles.
Then, abruptly, they were gone. All over the world, the large mammals that had characterized global ecosystems for tens of millions of years disappeared. North America lost more than 70% of mammals weighing more than 97 pounds (44 kilograms). South America lost more than 80%, Australia nearly 90%. Only Africa, Antarctica and a few remote islands retain what could be considered “natural” animal communities today.
The reason for these extinctions remains obscure. For decades, paleontologists and archaeologists have debated potential causes. What has befuddled scientists is not that there are no obvious culprits but that there are too many.
As the last ice age ended, a warming climate led to altered weather patterns and the reorganization of plant communities. At the same time, human populations were rapidly increasing and spreading around the globe.
Either or both of these processes could be implicated in the extinction event. But the fossil record of any region is usually too sparse to know exactly when large mammal species disappeared from different regions. This makes it difficult to determine whether habitat loss, resource scarcity, natural disasters, human hunting or some combination of these factors is to blame.
A deadly combination
Some records offer clues. La Brea Tar Pits in Los Angeles, the world’s richest ice age fossil site, preserves the bones of thousands of large mammals that were trapped in viscous asphalt seeps over the past 60,000 years. Proteins in these bones can be precisely dated using radioactive carbon, giving scientists unprecedented insight into an ancient ecosystem and an opportunity to illuminate the timing – and causes – of its collapse.
Our recent study from La Brea Tar Pits and nearby Lake Elsinore has unearthed evidence of a dramatic event 13,000 years ago that permanently transformed Southern California’s vegetation and caused the disappearance of La Brea’s iconic mega-mammals.
Sediment archives from the lake’s bottom and archaeological records provide evidence of a deadly combination – a warming climate punctuated by decadeslong droughts and rapidly rising human populations. These factors pushed the Southern California ecosystem to a tipping point.
Similar combinations of climate warming and human impacts have been blamed for ice age extinctions elsewhere, but our study found something new. The catalyst for this dramatic transformation seems to have been an unprecedented increase in wildfires, which were probably set by humans.
The processes that led to this collapse are familiar today. As California warmed coming out of the last ice age, the landscape became drier and forests receded. At La Brea, herbivore populations declined, probably from a combination of human hunting and habitat loss. Species associated with trees, like camels, disappeared entirely.
In the millennium leading up to the extinction, mean annual temperatures in the region rose 10 degrees Farenheit (5.5 degrees Celsius), and the lake began evaporating. Then, 13,200 years ago, the ecosystem entered a 200-year-long drought. Half of the remaining trees died. With fewer large herbivores to eat it, dead vegetation built up on the landscape.
