Connect with us

The Conversation

Tiny, compact galaxies are masters of disguise in the distant universe − searching for the secrets behind the Little Red Dots

Published

on

theconversation.com – Fabio Pacucci, Astrophysicist, Smithsonian Institution – 2024-09-06 07:36:33

Supermassive black holes grow by pulling in matter around them.

M. Kornmesser/ESO via AP

Fabio Pacucci, Smithsonian Institution

Astronomers exploring the faraway universe with the James Webb Space Telescope, NASA’s most powerful telescope, have found a class of galaxies that challenges even the most skillful creatures in mimicry – like the mimic octopus. This creature can impersonate other marine animals to avoid predators. Need to be a flatfish? No problem. A sea snake? Easy.

When astronomers analyzed the first Webb images of the remote parts of the universe, they spotted a never-before-seen group of galaxies. These galaxies – some hundreds of them and called the Little Red Dots – are very red and compact, and visible only during about 1 billion years of cosmic history. Like the mimic octopus, the Little Red Dots puzzle astronomers, because they look like different astrophysical objects. They’re either massively heavy galaxies or modestly sized ones, each containing a supermassive black hole at its core.

However, one thing is certain. The typical Little Red Dot is small, with a radius of only 2% of that of the Milky Way galaxy. Some are even smaller.

As an astrophysicist who studies faraway galaxies and black holes, I am interested in understanding the nature of these little galaxies. What powers their light and what are they, really?

Many galaxies, indicated as small, bright dots, shown against a dark backdrop.

The universe is full of countless galaxies, and the Webb telescope has helped astronomers study some of them.

NASA, ESA, CSA, STScI

The mimicking contest

Astronomers analyze the light our telescopes receive from faraway galaxies to assess their physical properties, such as the number of stars they contain. We can use the properties of their light to study the Little Red Dots and figure out whether they’re made up of lots of stars or whether they have a black hole inside them.

Light that reaches our telescopes ranges in wavelength from long radio waves to energetic gamma rays. Astronomers break the light down into the different frequencies and visualize them with a chart, called a spectrum.

Sometimes, the spectrum contains emission lines, which are ranges of frequencies where more intense light emission occurs. In this case, we can use the spectrum’s shape to predict whether the galaxy is harboring a supermassive black hole and estimate its mass.

Similarly, studying X-ray emisson from the galaxy can reveal a supermassive black hole’s presence.

As the ultimate masters of disguise, the Little Red Dots appear as different astrophysical objects, depending on whether astronomers choose to study them using X-rays, emission lines or something else.

The information astronomers have collected so far from the Little Red Dots’ spectra and emission lines has led to two diverging models explaining their nature. These objects are either extremely dense galaxies containing billions of stars or they host a supermassive black hole.

The two hypotheses

In the stars-only hypothesis, the Little Red Dots contain massive amounts of stars – up to 100 billion stars. That’s approximately the same number of stars as in the Milky Way – a much larger galaxy.

Imagine standing alone in a huge, empty room. This vast, quiet space represents the region of the universe in the vicinity of our solar system where stars are sparsely scattered. Now, picture that same room, but packed with the entire population of China.

This packed room is what the core of the densest Little Red Dots would feel like. These astrophysical objects may be the densest stellar environments in the entire universe. Astronomers aren’t even sure whether such stellar systems can physically exist.

Then, there is the black hole hypothesis. The majority of Little Red Dots display clear signs of the presence of a supermassive black hole in their center. Astronomers can tell whether there’s a black hole in the galaxy by looking at large emission lines in their spectra, created by gas around the black hole swirling at high speed.

Astronomers actually estimate these black holes are too massive, compared with the size of their compact host galaxies.

Black holes typically have a mass of about 0.1% of the stellar mass of their host galaxies. But some of these Little Red Dots harbor a black hole almost as massive as their entire galaxy. Astronomers call these overmassive black holes, because their existence defies the conventional ratio typically observed in galaxies.

YouTube video
Animation illustrating the James Webb Space Telescope’s discovery of overmassive black holes in the distant Universe. Credit: Timothy Rauch.

There’s another catch, though. Unlike ordinary black holes, those presumably present in the Little Red Dots don’t show any sign of X-ray emission. Even in the deepest, high-energy images available, where astronomers should be able to easily observe these black holes, there’s no trace of them.

Few solutions and plenty of hopes

So are these astrophysical curiosities massive galaxies with far too many stars? Or do they host supermassive black holes at their center that are too massive and don’t emit enough X-rays? What a puzzle.

With more observations and theoretical modeling, astronomers are starting to come up with some possible solutions. Maybe the Little Red Dots are composed only of stars, but these stars are so dense and compact that they mimic the emission lines typically seen from a black hole.

Or maybe supermassive – even overmassive – black holes lurk at the cores of these Little Red Dots. If that’s the case, two models can explain the lack of X-ray emissions.

First, vast amounts of gas could float around the black hole, which would block part of the high-energy radiation emitted from the black hole’s center. Second, the black hole could be pulling in gas much faster than usual. This process would produce a different spectrum with fewer X-rays than astronomers usually see.

The fact that the black holes are too big, or overmassive, might not be a problem for our understanding of the universe, but rather the best indication of how the first black holes in the universe were born. In fact, if the first black holes that ever formed were very massive – about 100,000 times the mass of the Sun – theoretical models suggest that their ratio of black hole mass to the mass of the host galaxy could stay high for a long time after formation.

So how can astronomers discover the true nature of these little specks of light that are shining at the beginning of time? As in the case of our master of disguise – the octopus – the secret resides in observing their behavior.

Using the Webb telescope and more powerful X-ray telescopes to take additional observations will eventually uncover a feature that astronomers can attribute to only one of the two scenarios.

For example, if astronomers clearly detected X-ray or radio emission, or infrared light emitted from around where the black hole might be, they’d know the black hole hypothesis is the right one.

Just like how our marine friend can pretend to be a starfish, eventually it will move its tentacles and reveal its true nature.The Conversation

Fabio Pacucci, Astrophysicist, Smithsonian Institution

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Read More

The post Tiny, compact galaxies are masters of disguise in the distant universe − searching for the secrets behind the Little Red Dots appeared first on theconversation.com

The Conversation

Being alone has its benefits − a psychologist flips the script on the ‘loneliness epidemic’

Published

on

theconversation.com – Virginia Thomas, Assistant Professor of Psychology, Middlebury – 2025-04-04 07:18:00

Studies show that choosing ‘me time’ is not a recipe for loneliness but can boost your creativity and emotional well-being.
FotoDuets/iStock via Getty Images Plus

Virginia Thomas, Middlebury

Over the past few years, experts have been sounding the alarm over how much time Americans spend alone.

Statistics show that we’re choosing to be solitary for more of our waking hours than ever before, tucked away at home rather than mingling in public. Increasing numbers of us are dining alone and traveling solo, and rates of living alone have nearly doubled in the past 50 years.

These trends coincided with the surgeon general’s 2023 declaration of a loneliness epidemic, leading to recent claims that the U.S. is living in an “anti-social century.”

Loneliness and isolation are indeed social problems that warrant serious attention, especially since chronic states of loneliness are linked with poor outcomes such as depression and a shortened lifespan.

But there is another side to this story, one that deserves a closer look. For some people, the shift toward aloneness represents a desire for what researchers call “positive solitude,” a state that is associated with well-being, not loneliness.

As a psychologist, I’ve spent the past decade researching why people like to be alone – and spending a fair amount of time there myself – so I’m deeply familiar with the joys of solitude. My findings join a host of others that have documented a long list of benefits gained when we choose to spend time by ourselves, ranging from opportunities to recharge our batteries and experience personal growth to making time to connect with our emotions and our creativity.

YouTube video
Being alone can help remind people who they are.

So it makes sense to me why people live alone as soon as their financial circumstances allow, and when asked why they prefer to dine solo, people say simply, “I want more me time.”

It’s also why I’m not surprised that a 2024 national survey found that 56% of Americans considered alone time essential for their mental health. Or that Costco is now selling “solitude sheds” where for around US$2,000 you can buy yourself some peace and quiet.

It’s clear there is a desire, and a market, for solitude right now in American culture. But why does this side of the story often get lost amid the warnings about social isolation?

I suspect it has to do with a collective anxiety about being alone.

The stigma of solitude

This anxiety stems in large part from our culture’s deficit view of solitude. In this type of thinking, the desire to be alone is seen as unnatural and unhealthy, something to be pitied or feared rather than valued or encouraged.

This isn’t just my own observation. A study published in February 2025 found that U.S. news headlines are 10 times more likely to frame being alone negatively than positively. This type of bias shapes people’s beliefs, with studies showing that adults and children alike have clear judgments about when it is – and importantly when it is not – acceptable for their peers to be alone.

This makes sense given that American culture holds up extraversion as the ideal – indeed as the basis for what’s normal. The hallmarks of extraversion include being sociable and assertive, as well as expressing more positive emotions and seeking more stimulation than the opposite personality – the more reserved and risk-averse introverts. Even though not all Americans are extraverts, most of us have been conditioned to cultivate that trait, and those who do reap social and professional rewards. In this cultural milieu, preferring to be alone carries stigma.

But the desire for solitude is not pathological, and it’s not just for introverts. Nor does it automatically spell social isolation and a lonely life. In fact, the data doesn’t fully support current fears of a loneliness epidemic, something scholars and journalists have recently acknowledged.

In other words, although Americans are indeed spending more time alone than previous generations did, it’s not clear that we are actually getting lonelier. And despite our fears for the eldest members of our society, research shows that older adults are happier in solitude than the loneliness narrative would lead us to believe.

YouTube video
It’s all a balancing act – along with solitude, you need to socialize.

Social media disrupts our solitude

However, solitude’s benefits don’t automatically appear whenever we take a break from the social world. They arrive when we are truly alone – when we intentionally carve out the time and space to connect with ourselves – not when we are alone on our devices.

My research has found that solitude’s positive effects on well-being are far less likely to materialize if the majority of our alone time is spent staring at our screens, especially when we’re passively scrolling social media.

This is where I believe the collective anxiety is well placed, especially the focus on young adults who are increasingly forgoing face-to-face social interaction in favor of a virtual life – and who may face significant distress as a result.

Social media is by definition social. It’s in the name. We cannot be truly alone when we’re on it. What’s more, it’s not the type of nourishing “me time” I suspect many people are longing for.

True solitude turns attention inward. It’s a time to slow down and reflect. A time to do as we please, not to please anyone else. A time to be emotionally available to ourselves, rather than to others. When we spend our solitude in these ways, the benefits accrue: We feel rested and rejuvenated, we gain clarity and emotional balance, we feel freer and more connected to ourselves.

But if we’re addicted to being busy, it can be hard to slow down. If we’re used to looking at a screen, it can be scary to look inside. And if we don’t have the skills to validate being alone as a normal and healthy human need, then we waste our alone time feeling guilty, weird or selfish.

The importance of reframing solitude

Americans choosing to spend more time alone is indeed a challenge to the cultural script, and the stigmatization of solitude can be difficult to change. Nevertheless, a small but growing body of research indicates that it is possible, and effective, to reframe the way we think about solitude.

For example, viewing solitude as a beneficial experience rather than a lonely one has been shown to help alleviate negative feelings about being alone, even for the participants who were severely lonely. People who perceive their time alone as “full” rather than “empty” are more likely to experience their alone time as meaningful, using it for growth-oriented purposes such as self-reflection or spiritual connection.

Even something as simple as a linguistic shift – replacing “isolation” with “me time” – causes people to view their alone time more positively and likely affects how their friends and family view it as well.

It is true that if we don’t have a community of close relationships to return to after being alone, solitude can lead to social isolation. But it’s also true that too much social interaction is taxing, and such overload negatively affects the quality of our relationships. The country’s recent gravitational pull toward more alone time may partially reflect a desire for more balance in a life that is too busy, too scheduled and, yes, too social.

Just as connection with others is essential for our well-being, so is connection with ourselves.The Conversation

Virginia Thomas, Assistant Professor of Psychology, Middlebury

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Read More

The post Being alone has its benefits − a psychologist flips the script on the ‘loneliness epidemic’ appeared first on theconversation.com

Continue Reading

The Conversation

Measles can ravage the immune system and brain, causing long-term damage – a virologist explains

Published

on

theconversation.com – Peter Kasson, Professor of Chemistry and Biomedical Engineering, Georgia Institute of Technology – 2025-03-31 07:16:00

Measles infections send 1 in 5 people to the hospital.
wildpixel/ iStock via Getty Images Plus

Peter Kasson, Georgia Institute of Technology

The measles outbreak that began in west Texas in late January 2025 continues to grow, with 400 confirmed cases in Texas and more than 50 in New Mexico and Oklahoma as of March 28.

Public health experts believe the numbers are much higher, however, and some worry about a bigger resurgence of the disease in the U.S. In the past two weeks, health officials have identified potential measles exposures in association with planes, trains and automobiles, including at Washington Dulles International Airport and on an Amtrak train from New York City to Washington, D.C. – as well as at health care facilities where the infected people sought medical attention.

Measles infections can be extremely serious. So far in 2025, 14% of the people who got measles had to be hospitalized. Last year, that number was 40%. Measles can damage the lungs and immune system, and also inflict permanent brain damage. Three in 1,000 people who get the disease die. But because measles vaccination programs in the U.S. over the past 60 years have been highly successful, few Americans under 50 have experienced measles directly, making it easy to think of the infection as a mere childhood rash with fever.

As a biologist who studies how viruses infect and kill cells and tissues, I believe it is important for people to understand how dangerous a measles infection can be.

Underappreciated acute effects

Measles is one of the most contagious diseases on the planet. One person who has it will infect nine out of 10 people nearby if those people are unvaccinated. A two-dose regimen of the vaccine, however, is 97% effective at preventing measles.

When the measles virus infects a person, it binds to specific proteins on the surface of cells. It then inserts its genome and replicates, destroying the cells in the process. This first happens in the upper respiratory tract and the lungs, where the virus can damage the person’s ability to breathe well. In both places, the virus also infects immune cells that carry it to the lymph nodes, and from there, throughout the body.

YouTube video
Measles can wipe out immune cells’ ability to recognize pathogens.

What generally lands people with measles in the hospital is the disease’s effects on the lungs. As the virus destroys lung cells, patients can develop viral pneumonia, which is characterized by severe coughing and difficulty breathing. Measles pneumonia afflicts about 1 in 20 children who get measles and is the most common cause of death from measles in young children.

The virus can directly invade the nervous system and also damage it by causing inflammation. Measles can cause acute brain damage in two different ways: a direct infection of the brain that occurs in roughly 1 in 1,000 people, or inflammation of the brain two to 30 days after infection that occurs with the same frequency. Children who survive these events can have permanent brain damage and impairments such as blindness and hearing loss.

Yearslong consequences of infection

An especially alarming but still poorly understood effect of measles infection is that it can reduce the immune system’s ability to recognize pathogens it has previously encountered. Researchers had long suspected that children who get the measles vaccine also tend to have better immunity to other diseases, but they were not sure why. A study published in 2019 found that having a measles infection destroyed between 11% and 75% of their antibodies, leaving them vulnerable to many of the infections to which they previously had immunity. This effect, called immune amnesia, lasts until people are reinfected or revaccinated against each disease their immune system forgot.

Occasionally, the virus can lie undetected in the brain of a person who recovered from measles and reactivate typically seven to 10 years later. This condition, called subacute sclerosing panencephalitis, is a progressive dementia that is almost always fatal. It occurs in about 1 in 25,000 people who get measles but is about five times more common in babies infected with measles before age 1.

Researchers long thought that such infections were caused by a special strain of measles, but more recent research suggests that the measles virus can acquire mutations that enable it to infect the brain during the course of the original infection.

There is still much to learn about the measles virus. For example, researchers are exploring antibody therapies to treat severe measles. However, even if such treatments work, the best way to prevent the serious effects of measles is to avoid infection by getting vaccinated.The Conversation

Peter Kasson, Professor of Chemistry and Biomedical Engineering, Georgia Institute of Technology

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Read More

The post Measles can ravage the immune system and brain, causing long-term damage – a virologist explains appeared first on theconversation.com

Continue Reading

The Conversation

Supreme Court considers whether states may prevent people covered by Medicaid from choosing Planned Parenthood as their health care provider

Published

on

theconversation.com – Naomi Cahn, Professor of Law, University of Virginia – 2025-04-02 17:04:00

Planned Parenthood clinics, like this one in Los Angeles, are located across the United States.
Patrick T. Fallon/AFP via Getty Images

Naomi Cahn, University of Virginia and Sonia Suter, George Washington University

Having the freedom to choose your own health care provider is something many Americans take for granted. But the Supreme Court is weighing whether people who rely on Medicaid for their health insurance have that right, and if they do – is it enforceable by law?

That’s the key question at the heart of a case, Medina v. Planned Parenthood South Atlantic, that began during President Donald Trump’s first term in office.

“There’s a right, and the right is the right to choose your doctor,” said Justice Elena Kagan on April 2, 2025, during oral arguments on the case. John J. Bursch, the Alliance Defending Freedom lawyer who is representing South Carolina Director of Health and Human Services Eunice Medina, countered that none of the words in the underlying statute had what he called a “rights-creating pedigree.”

As law professors who teach courses about health and poverty law as well as reproductive justice, we think this case could affect access to health care for 72 million Americans, including low-income people and their children and people with disabilities.

Excluding Planned Parenthood

The case started with Julie Edwards, who is enrolled in Medicaid and lives in South Carolina. After she struggled to get contraceptive services, she was able to receive care from a Planned Parenthood South Atlantic clinic in Columbia, South Carolina.

Planned Parenthood, an array of nonprofits with roots that date back more than a century, is among the nation’s top providers of reproductive services. It operates two clinics in South Carolina, where Medicaid patients can get physical exams, cancer screenings, contraception and other services. It also provides same-day appointments and keeps long hours.

In July 2018, however, South Carolina Gov. Henry McMaster issued an executive order that barred health care providers in South Carolina that offer abortions from reimbursement through Medicaid.

That meant Planned Parenthood, a longtime target of conservatives’ ire, would no longer be reimbursed for any type of care for Medicaid patients, preventing Edwards from transferring all her gynecological care to that office as she had hoped to do.

Planned Parenthood and Edwards sued South Carolina, claiming that the state was violating the federal Medicare and Medicaid Act, which Congress passed in 1965, by not letting Edwards obtain care from the provider of her choice.

A ‘free-choice-of-provider’ requirement

Medicaid operates as a partnership between the federal government and the states. Congress passed the law that led to its creation based on its power under the Constitution’s spending clause, which allows Congress to subject federal funds to certain requirements.

Two years later, due to concerns that states were restricting which providers Medicaid recipients could choose, Congress added a “free-choice-of-provider” requirement to the program. It states that people enrolled in Medicaid “may obtain such assistance from any institution, agency, community pharmacy, or person, qualified to perform the service or services required.”

This provision is at the core of this case. At issue is whether a civil rights statute provides a right for Medicaid beneficiaries to sue a state when their federal rights have been violated. Known as Section 1983, it was enacted in 1871.

Bursch, backed by the Trump administration, argued before the court that the absence of words like “right” in the Medicaid provision that requires states to provide a free choice of provider means that neither Edwards nor Planned Parenthood has the authority to file a lawsuit to enforce this aspect of the Medicaid statute.

Nicole A. Saharsky, Planned Parenthood’s lawyer, argued that the creation of a right shouldn’t depend on “some kind of magic words test.” Instead, she said it was clear that the Medicaid statute created “a right to choose their own doctor” because “it’s mandatory” that the state provide this option to everyone with health insurance through Medicaid.

She also emphasized that Congress wanted to protect “an intensely personal right” to be able “to choose your doctor, the person that you see when you’re at your most vulnerable, facing … some of the most significant … challenges to your life and your health.”

Restricting Medicaid funds

Through a federal law known as the Hyde Amendment, Medicaid cannot reimburse health care providers for the cost of abortions, with a few exceptions: when a patient’s life is at risk or her pregnancy is due to rape or incest. Some states do cover abortion when their laws allow it, without using any federal funds.

Therefore, Planned Parenthood only gets federal Medicaid funds for abortions in those limited circumstances.

McMaster explained that he removed “abortion clinics,” including Planned Parenthood, from the South Carolina Medicaid Program because he didn’t want state funds to indirectly subsidize abortions.

South Carolina “decided that Planned Parenthood was unqualified for many reasons, chiefly because they’re the nation’s largest abortion provider,” Bursch told the Supreme Court.

But only 3% of Planned Parenthood’s services nationwide last year were related to abortion. Its most common service is testing for sexually transmitted diseases. Across the nation, Planned Parenthood provides health care to more than 2 million patients per year, most of whom have low incomes.

Man with gray hair in a suit and red tie speaks at a podium.
South Carolina Gov. Henry McMaster speaks to a crowd during an election night party on Nov. 3, 2020, in Columbia.
Photo by Sean Rayford/Getty Images

Section 1983

Because the Medicaid statute itself does not allow an individual to sue, Edwards and Planned Parenthood are relying on Section 1983.

Lower courts have repeatedly upheld that the Medicaid statute provides Edwards with the right to obtain Medicaid-funded health care at her local Planned Parenthood clinic.

And the Supreme Court has long recognized that Section 1983 protects an individual’s ability to sue when their rights under a federal statute have been violated.

In 2023, for example, the court found such a right under the Medicaid Nursing Home Reform Act. The court held that Section 1983 confers the right to sue when a statute’s provisions “unambiguously confer individual federal rights.”

Consequences beyond South Carolina

The court’s decision in the Medina case on whether Medicaid patients can choose their own health care provider could have consequences far beyond South Carolina. Arkansas, Missouri and Texas have already barred Planned Parenthood from getting reimbursed by Medicaid for any kind of health care. More states could follow suit.

In addition, given Planned Parenthood’s role in providing expansive contraceptive care, disqualifying it from Medicaid could harm access to health care and increase the already-high unintended pregnancy rate in America.

The ramifications, likewise, could extend beyond the finances of Planned Parenthood.

If the court rules in South Carolina’s favor, states could also try to exclude providers based on other characteristics, such as whether their employees belong to unions or if they provide their patients with gender-affirming care, further restricting patients’ choices.

Or, as Kagan observed, states could go the opposite direction and exclude providers that don’t provide abortions and so forth. What’s really at stake, she said, is whether a patient is “entitled to see” the provider they choose regardless of what their state happens to “think about contraception or abortion or gender transition treatment.”

If the Supreme Court rules that Edwards does have a right to get health care at a Planned Parenthood clinic, the controversy would not be over. The lower courts would then have to decide whether South Carolina appropriately removed Planned Parenthood from Medicaid as an “unqualified provider.”

And if the Supreme Court rules in favor of South Carolina, then Planned Parenthood could still sue South Carolina over its decision to find them to be unqualified.The Conversation

Naomi Cahn, Professor of Law, University of Virginia and Sonia Suter, Professor of Law, George Washington University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Read More

The post Supreme Court considers whether states may prevent people covered by Medicaid from choosing Planned Parenthood as their health care provider appeared first on theconversation.com

Continue Reading

Trending