The new source, dubbed GRB 221009A for its discovery date, turned out to be the brightest gamma-ray burst (GRB) ever recorded.

In a new study that appears today in the Astrophysical Journal Letters, observations of GRB 221009A spanning from radio waves to gamma-rays, including critical millimeter-wave observations with the Center for Astrophysics | Harvard & Smithsonian’s Submillimeter Array (SMA) in Hawaii, shed new light on the decades-long quest to understand the origin of these extreme cosmic explosions.

The gamma-ray emission from GRB 221009A lasted over 300 seconds. Astronomers think that such “long-duration” GRBs are the birth cry of a black hole, formed as the core of a massive and rapidly spinning star collapses under its own weight. The newborn black hole launches powerful jets of plasma at near the speed of light, which pierce through the collapsing star and shine in gamma-rays.

With GRB 221009A being the brightest burst ever recorded, a real mystery lay in what would come after the initial burst of gamma-rays. “As the jets slam into gas surrounding the dying star, they produce a bright `afterglow’ of light across the entire spectrum,” says Tanmoy Laskar, assistant professor of physics and astronomy at the University of Utah, and lead author of the study. “The afterglow fades quite rapidly, which means we have to be quick and nimble in capturing the light before it disappears, taking its secrets with it.”

As part of a campaign to use the world’s best radio and millimeter telescopes to study the afterglow of GRB 221009A, astronomers Edo Berger and Yvette Cendes of the Center for Astrophysics (CfA) rapidly gathered data with the SMA.

“This burst, being so bright, provided a unique opportunity to explore the detailed behavior and evolution of an afterglow with unprecedented detail — we did not want to miss it!” says Edo Berger, professor of astronomy at Harvard University and the CfA. “I have been studying these events for more than twenty years, and this one was as exciting as the first GRB I ever observed.”

“Thanks to its rapid-response capability, we were able to quickly turn the SMA to the location of GRB 221009A,” says SMA project scientist and CfA researcher Garrett Keating. “The team was excited to see just how bright the afterglow of this GRB was, which we were able to continue to monitor for more than 10 days as it faded.”

After analyzing and combining the data from the SMA and other telescopes all over the world, the astronomers were flummoxed: the millimeter and radio wave measurements were much brighter than expected based on the visible and X-ray light.

“This is one of the most detailed datasets we have ever collected, and it is clear that the millimeter and radio data just don’t behave as expected,” says CfA research associate Yvette Cendes. “A few GRBs in the past have shown a brief excess of millimeter and radio emission that is thought to be the signature of a shockwave in the jet itself, but in GRB 221009A the excess emission behaves quite differently than in these past cases.”

She adds, “It is likely that we have discovered a completely new mechanism to produce excess millimeter and radio waves.”

One possibility, says Cendes, is that the powerful jet produced by GRB 221009A is more complex than in most GRBs. “It is possible that the visible and X-ray light are produced by one portion of the jet, while the early millimeter and radio waves are produced by a different component.”

“Luckily, this afterglow is so bright that we will continue to study its radio emission for months and maybe years to come,” adds Berger. “With this much longer time span we hope to decipher the mysterious origin of the early excess emission.”

Independent of the exact details of this particular GRB, the ability to respond rapidly to GRBs and similar events with millimeter-wave telescopes is an essential new capability for astronomers.

“A key lesson from this GRB is that without fast-acting radio and millimeter telescopes, such as the SMA, we would miss out on potential discoveries about the most extreme explosions in the universe,” says Berger. “We never know in advance when such events will occur, so we have to be as responsive as possible if we’re going to take advantage of these gifts from the cosmos.”

“In the past, industries have promptly shifted away from the usage of toxic chemicals only to produce an equally toxic chemical, so this is something we are actively trying to avoid repeating,” said Kyle Sease, a graduate student at Central Washington University in Ellensburg, Washington. “Our study suggests that ATBC, but not other non-phthalate alternatives, could interfere with cells that maintain brain health. We think this finding warrants further testing of ATBC at different doses, in different settings and in whole organism models.”

Sease will present the new research at Discover BMB, the annual meeting of the American Society for Biochemistry and Molecular Biology, March 25-28 in Seattle.

Phthalates are used in hundreds of products, often to enhance durability or allow materials to bend and stretch. Studies have shown that phthalate exposure can affect the reproductive system and early development in a range of animals, although the health impacts in humans are not clear. ATBC has emerged as a leading phthalate alternative as companies seek to shift away from phthalates and is currently used in a variety of materials and products, including food and food packaging.

For the study, researchers grew cultures of neuroblastoma cells, which, in terms of growth and division, behave similarly to the glial cells that support and protect neurons in the brain. They then used molecular methods to study how ATBC and other chemicals affect genes and processes involved in cellular division. They found that neuroblastoma cells exposed to ATBC increased their expression of two genes associated with cellular stress (known as Nrf2 and p53) and also increased their production of an enzyme associated with cellular senescence (B-galactosidase), which can cause cells to stop growing and dividing.

The findings suggest that ATBC could interfere with the ability for glial cells to regenerate, which can reduce their ability to protect neural cells and lead to neurodegeneration and accelerated aging. It is also possible that ATBC exposure during early development — when neurons are actively growing and dividing — could affect neurons directly and interfere with brain development, the researchers said. Since neurons do not typically regrow once damaged, any effects on the brain likely would be permanent.

Two other phthalate alternatives, bis (2-ethylhexyl)-1, 4-benzenedicarboxylate (GPO) and dioctyl adipate (DOA), did not show the same effects as ATBC. “We found that two other plasticizers did not appear to affect cell division in these cells, so further understanding the different effects of different plasticizers will allow us to understand better how to make safe ones,” Sease said.

Kyle Sease will present this research from 4:30-6:30 p.m. PDT on Monday, March 27, in Exhibit Hall 4AB of the Seattle Convention Center (Poster Board No. 141) (abstract).

Research in recent years has shown that postponing the start time of high schools improves the amount of sleep that students get and reduces their sleepiness during school hours. But findings are mixed about whether this has a positive impact on grades.

To determine the impact specifically on university students, Associate Professor Joshua Gooley, from Duke-NUS’ Neuroscience & Behavioural Disorders Programme and colleagues used student Wi-Fi connection data, log-ins to university digital learning platforms, and activity data from special sensing watches to conduct large-scale monitoring of class attendance and sleep behaviour of tens of thousands of university students.

“We implemented new methods that allow large-scale monitoring of class attendance and sleep behaviour by analysing students’ classroom Wi-Fi connection data and their interactions with digital learning platforms,” said Dr Yeo Sing Chen, first author of the study and a Duke-NUS PhD graduate.

From the data, the researchers found that early class start times were associated with lower attendance, with many students regularly sleeping past the start of such classes. When students did attend an early class, they lost about an hour of sleep. Morning classes on more days of the week were also associated with a lower grade point average.

“If the goal of formal education is to position our students to succeed in the classroom and workforce, why are we forcing many university students into the bad decision of either skipping morning class to sleep more or attending class while sleep-deprived?” asked Assoc Prof Gooley. “The take-home message from our study is that universities should reconsider mandatory early morning classes.”

The researchers drew insights using the Wi-Fi connection logs of 23,391 students to find out if early morning classes were associated with lower attendance. They then compared the data with six weeks of watch-derived activity data from a subset of 181 students to determine if the students were sleeping instead of attending early morning classes.

They also analysed activity data with the day and night patterns of digital learning platform logins of 39,458 students to determine if early morning classes were associated with waking up earlier and getting less sleep. Finally, they studied the grades of 33,818 students and the number of morning classes these students were taking to determine if it impacted their grade point average.

The team is now investigating differences between class attendance, sleep, wellbeing and academic performance between early birds and night owls. “We expect to find that evening-type students will be at a learning disadvantage in early morning classes and have lower class attendance, shorter sleep, poorer mental health and lower grades compared with their peers,” said Assoc Prof Gooley.

People affected by obesity or who are overweight are at increased risk for high cholesterol and high blood pressure — factors that heighten risk of cardiovascular disease; as well as insulin resistance, a precursor to Type 2 diabetes. Globally, overweight and obesity contributed to 2.4 million deaths in 2020, according to the American Heart Association’s 2023 Statistical Update.

Behavioral weight loss programs can help people lose and maintain a healthy weight by encouraging lifestyle and behavior changes, such as eating healthy foods and increasing physical activity. Regaining some weight is common after behavioral weight loss programs. Some observational studies suggest this weight change pattern of weight loss followed by weight regain may increase cardiovascular risk. However, according to the authors of this analysis, data from randomized trials and long-term follow-up studies is lacking.

“Many doctors and patients recognize that weight loss is often followed by weight regain, and they fear that this renders an attempt to lose weight pointless,” said study co-senior author Susan A. Jebb, Ph.D., a professor of diet and population health at the University of Oxford in the United Kingdom. “This concept has become a barrier to offering support to people to lose weight. For people with overweight or obesity issues, losing weight is an effective way to reduce the risk of Type 2 diabetes and cardiovascular disease.”

In this review, researchers assessed international scientific studies available in 2018 to compare risk factors for cardiovascular disease and Type 2 diabetes among people who followed an intensive behavioral weight loss program to those who followed a less intensive or no weight loss program. The studies in the analysis included diet and/or exercise interventions, partial or total meal replacement, intermittent fasting, or financial incentives contingent on weight loss. The studies took place in a variety of settings and included varying modes of delivery (in person, app-based, telephone, etc.).

Researchers combined the results of 124 studies totaling more than 50,000 participants, with an average follow-up of 28 months. They used the combined results to estimate changes in risk factors for cardiovascular disease and Type 2 diabetes after weight loss. The average weight loss across the different studies ranged from 2-5 kilograms, or 5-10 pounds. Weight regain averaged 0.12 to 0.32 kg (0.26 pounds to 0.7 pounds) a year. Participants were an average age 51 years old, with a body mass index of 33, which is considered obese.

Compared to people in a less intensive program and those in no weight loss program, participants who lost weight through an intensive weight loss program had lower risk factors for cardiovascular disease and Type 2 diabetes. These lower risk factors lasted for at least five years after the weight loss program ended.

Based on pooled results of the studies reviewed, on average:

• Systolic blood pressure, the top number in a blood pressure reading, was 1.5 mm Hg (millimeters of mercury) lower at one year, and 0.4 mm Hg lower at five years after participation in an intensive weight loss program.
• In addition, the percentage of HbA1c, a protein in red blood cells used to test for diabetes, was reduced by 0.26 at both one and five years after participation in an intensive weight loss program.
• The ratio of total cholesterol to good cholesterol – known as high-density lipoprotein (HDL) cholesterol — was 1.5 points lower one year and five years after participation in an intensive weight loss program.

These changes are important because they represent improvements at the population level, Jebb explained.

In a preliminary finding, the decreased risk of being diagnosed with cardiovascular disease or Type 2 diabetes also appeared to remain lower even after weight regain. However, few studies followed people for more than 5 years and “more information is needed to confirm whether this potential benefit persists,” Jebb said.

“Most trials look at whether new treatments are effective and focus on weight change in the short-term rather than the effect on later disease,” Jebb said. “Individual studies are often too small to detect differences between groups in the incidence of cardiovascular conditions because, fortunately, they affect only a small proportion of the whole group, and studies may not continue long enough to see the effects on ‘hard’ outcomes, such as a new diagnosis of Type 2 diabetes or a heart attack.

“Our findings should provide reassurance that weight loss programs are effective in controlling cardiovascular risk factors and very likely to reduce the incidence of cardiovascular disease,” she said.

Evidence suggests that cardiovascular health is improved by following the American Heart Association’s Life’s Essential 8 health metrics: eating healthy food, being physically active, not smoking, getting enough sleep, maintaining a healthy weight, and controlling cholesterol, blood sugar and blood pressure levels.

The analysis had several limitations: information included in the review was not updated after 2019 and the review focused on research papers published in English, so eligible studies written in other languages may have been missed.

An accompanying editorial notes that much remains to be understood about various weight loss interventions, their long-term impact and how this impact may be diminished by regaining weight. Behavioral weight loss programs constitute the backbone of weight management in clinical practice. However, they are often resource intensive, and emerging medication therapies are expensive, according to editorial authors Vishal N. Rao, M.D., M.P.H., and Neha J. Pagidipati, M.D., M.P.H., both from the division of cardiology at Duke University School of Medicine in Durham, North Carolina.

“The present study has interesting implications for the impact of weight regain that may occur after pharmacologic therapies,” they write. “What is still unknown is whether these temporary improvements in weight and cardiometabolic risk factors after weight loss intervention (behavioral or pharmacological) lead to long-term clinical benefit. In other words, is it better to have lost and regained than never to have lost at all?”

The team of scientists from the USA, California, France, the Netherlands, Chile and Hawaii observed 18 asteroids sharing the orbit of Neptune, known as Neptunian Trojans. They are between 50 and 100 km in size and are located at a distance of around 4.5 billion kilometres from the Sun. Asteroids orbiting this far away are faint and so are challenging for astronomers to study. Before the new work, only about a dozen Neptunian Trojans had been studied, requiring the use of some of the largest telescopes on Earth.

The new data were gathered over the course of two years using the WASP wide field camera on the Palomar Observatory telescope in California, the GMOS cameras on the Gemini North and South telescopes in Hawaii and Chile, and the LRIS camera on the Keck Telescope in Hawaii.

Of the 18 observed Neptunian Trojans, several were much redder than most asteroids, and compared with other asteroids in this group looked at in previous studies. Redder asteroids are expected to have formed much further from the Sun; one population of these is known as the Cold Classical trans-Neptunian objects found beyond the orbit of Pluto, at around 6 billion kilometres from the Sun. The newly observed Neptunian Trojans are also unlike asteroids located in the orbit of Jupiter, which are typically more neutral in colour.

The redness of the asteroids implies that they contain a higher proportion of more volatile ices such as ammonia and methanol. These are extremely sensitive to heat, and can rapidly transform into gas if the temperature rises, so are more stable at large distances from the Sun.

The location of the asteroids at the same orbital distance as Neptune also implies that they are stable on timescales comparable to the age of the Solar System. They effectively act as a time-capsule, recording the initial conditions of the Solar System.

The presence of redder asteroids among the Neptunian Trojans suggests the existence of a transition zone between more neutral coloured and redder objects. The redder Neptunian asteroids may have formed beyond this transition boundary before being captured into the orbit of Neptune. The Neptunian Trojans would have been captured into the same orbit as the planet Neptune as the ice giant planet migrated from the inner solar system to where it is now, some 4.5 billion kilometres from the Sun.

Lead author Dr Bryce Bolin of the NASA Goddard Space Flight Centre said, “In our new work we have more than doubled the sample of Neptunian Trojans studied with large telescopes. It’s exciting to find the first evidence of redder asteroids in this group.”

“Because we have a larger sample of Neptunian Trojans with measured colours, we can now start to see major differences between asteroid groups. Our observations also show that the Neptunian Trojans are also different in colour compared to asteroid groups even further from the Sun. A possible explanation may be that the processing of the surfaces of asteroids by the Sun’s heat may have different effects for asteroids at varying solar distances.”

According to a new paper by Concordia researchers published in the Journal of Cognition and Development, the answer largely depends on age.

The study compared two groups of preschoolers: one of three-year-olds, the other of five-year-olds. The children participated in Zoom meetings featuring a video of a young woman and a small robot with humanoid characteristics (head, face, torso, arms and legs) called Nao sitting side by side. Between them were familiar objects that the robot would label correctly while the human would label them incorrectly, e.g., referring to a car as a book, a ball as a shoe and a cup as a dog.

Next, the two groups of children were presented with unfamiliar items: the top of a turkey baster, a roll of twine and a silicone muffin container. Both the robot and the human used different nonsense terms like “mido,” “toma,” “fep” and “dax” to label the objects. The children were then asked what the object was called, endorsing either the label offered by the robot or by the human.

While the three-year-olds showed no preference for one word over another, the five-year-olds were much more likely to state the term provided by the robot than the human.

“We can see that by age five, children are choosing to learn from a competent teacher over someone who is more familiar to them — even if the competent teacher is a robot,” says the paper’s lead author, PhD candidate Anna-Elisabeth Baumann. Horizon Postdoctoral Fellow Elizabeth Goldman and undergraduate research assistant Alexandra Meltzer also contributed to the study. Professor and Concordia University Chair of Developmental Cybernetics Diane Poulin-Dubois in the Department of Psychology supervised the study.

The researchers repeated the experiments with new groups of three- and five-year-olds, replacing the humanoid Nao with a small truck-shaped robot called Cozmo. The results resembled those observed with the human-like robot, suggesting that the robot’s morphology does not affect the children’s selective trust strategies.

Baumann adds that, along with the labelling task, the researchers administered a naive biology task. The children were asked if biological organs or mechanical gears formed the internal parts of unfamiliar animals and robots. The three-year-olds appeared confused, assigning both biological and mechanical internal parts to the robots. However, the five-year-olds were much more likely to indicate that only mechanical parts belonged inside the robots.

“This data tells us that the children will choose to learn from a robot even though they know it is not like them. They know that the robot is mechanical,” says Baumann.

Being right is better than being human

While there has been a substantial amount of literature on the benefits of using robots as teaching aides for children, the researchers note that most studies focus on a single robot informant or two robots pitted against each other. This study, they write, is the first to use both a human speaker and a robot to see if children deem social affiliation and similarity more important than competency when choosing which source to trust and learn from.

Poulin-Dubois points out that this study builds on a previous paper she co-wrote with Goldman and Baumann. That paper shows that by age five, children treat robots similarly to how adults do, i.e., as depictions of social agents.

“Older preschoolers know that robots have mechanical insides, but they still anthropomorphize them. Like adults, these children attribute certain human-like qualities to robots, such as the ability to talk, think and feel,” she says.

“It is important to emphasize that we see robots as tools to study how children can learn from both human and non-human agents,” concludes Goldman. “As technology use increases, and as children interact with technological devices more, it is important for us to understand how technology can be a tool to help facilitate their learning.”

This is the first detection of any form of light emitted by an exoplanet as small and as cool as the rocky planets in our own solar system. The result marks an important step in determining whether planets orbiting small active stars like TRAPPIST-1 can sustain atmospheres needed to support life. It also bodes well for Webb’s ability to characterize temperate, Earth-sized exoplanets using MIRI.

“These observations really take advantage of Webb’s mid-infrared capability,” said Thomas Greene, an astrophysicist at NASA’s Ames Research Center and lead author on the study published today in the journal Nature. “No previous telescopes have had the sensitivity to measure such dim mid-infrared light.”

Rocky Planets Orbiting Ultracool Red Dwarfs

In early 2017, astronomers reported the discovery of seven rocky planets orbiting an ultracool red dwarf star (or M dwarf) 40 light-years from Earth. What is remarkable about the planets is their similarity in size and mass to the inner, rocky planets of our own solar system. Although they all orbit much closer to their star than any of our planets orbit the Sun – all could fit comfortably within the orbit of Mercury – they receive comparable amounts of energy from their tiny star.

TRAPPIST-1 b, the innermost planet, has an orbital distance about one hundredth that of Earth’s and receives about four times the amount of energy that Earth gets from the Sun. Although it is not within the system’s habitable zone, observations of the planet can provide important information about its sibling planets, as well as those of other M-dwarf systems.

“There are ten times as many of these stars in the Milky Way as there are stars like the Sun, and they are twice as likely to have rocky planets as stars like the Sun,” explained Greene. “But they are also very active – they are very bright when they’re young, and they give off flares and X-rays that can wipe out an atmosphere.”

Co-author Elsa Ducrot from the French Alternative Energies and Atomic Energy Commission (CEA) in France, who was on the team that conducted earlier studies of the TRAPPIST-1 system, added, “It’s easier to characterize terrestrial planets around smaller, cooler stars. If we want to understand habitability around M stars, the TRAPPIST-1 system is a great laboratory. These are the best targets we have for looking at the atmospheres of rocky planets.”

Detecting an Atmosphere (or Not)

Previous observations of TRAPPIST-1 b with the Hubble and Spitzer space telescopes found no evidence for a puffy atmosphere, but were not able to rule out a dense one.

One way to reduce the uncertainty is to measure the planet’s temperature. “This planet is tidally locked, with one side facing the star at all times and the other in permanent darkness,” said Pierre-Olivier Lagage from CEA, a co-author on the paper. “If it has an atmosphere to circulate and redistribute the heat, the dayside will be cooler than if there is no atmosphere.”

The team used a technique called secondary eclipse photometry, in which MIRI measured the change in brightness from the system as the planet moved behind the star. Although TRAPPIST-1 b is not hot enough to give off its own visible light, it does have an infrared glow. By subtracting the brightness of the star on its own (during the secondary eclipse) from the brightness of the star and planet combined, they were able to successfully calculate how much infrared light is being given off by the planet.

Measuring Minuscule Changes in Brightness

Webb’s detection of a secondary eclipse is itself a major milestone. With the star more than 1,000 times brighter than the planet, the change in brightness is less than 0.1%.

“There was also some fear that we’d miss the eclipse. The planets all tug on each other, so the orbits are not perfect,” said Taylor Bell, the post-doctoral researcher at the Bay Area Environmental Research Institute who analyzed the data. “But it was just amazing: The time of the eclipse that we saw in the data matched the predicted time within a couple of minutes.”

The team analyzed data from five separate secondary eclipse observations. “We compared the results to computer models showing what the temperature should be in different scenarios,” explained Ducrot. “The results are almost perfectly consistent with a blackbody made of bare rock and no atmosphere to circulate the heat. We also didn’t see any signs of light being absorbed by carbon dioxide, which would be apparent in these measurements.”

This research was conducted as part of Webb Guaranteed Time Observation (GTO) program 1177, which is one of eight programs from Webb’s first year of science designed to help fully characterize the TRAPPIST-1 system. Additional secondary eclipse observations of TRAPPIST-1 b are currently in progress, and now that they know how good the data can be, the team hopes to eventually capture a full phase curve showing the change in brightness over the entire orbit. This will allow them to see how the temperature changes from the day to the nightside and confirm if the planet has an atmosphere or not.

“There was one target that I dreamed of having,” said Lagage, who worked on the development of the MIRI instrument for more than two decades. “And it was this one. This is the first time we can detect the emission from a rocky, temperate planet. It’s a really important step in the story of discovering exoplanets.”