How many satellites are orbiting Earth?

 

Thousands of the satellites orbiting Earth are small – like this cubical satellite seen here being released from the International Space Station. NASA, CC BY-NC

CC BY-ND

It seems like every week, another rocket is launched into space carrying rovers to Mars, tourists or, most commonly, satellites. The idea that “space is getting crowded” has been around for a few years now, but just how crowded is it? And how crowded is it going to get?

I am a professor of physics and director of the Center for Space Science and Technology at the University of Massachusetts, Lowell. Many satellites that were put into orbit have gone dead and burned up in the atmosphere, but thousands remain. Groups that track satellite launches don’t always report the same exact numbers, but the overall trend is clear – and astounding.

Since the Soviet Union launched Sputnik – the first human-made satellite – in 1957, humanity has steadily been putting more and more objects into orbit every year. Over the the second half of the 20th century, there was a slow but steady growth, with roughly 60 to 100 satellites launched yearly until the early 2010s.

But since then, the pace has been increasing dramatically.

By 2020, 114 launches carried around 1,300 satellites to space, surpassing the 1,000 new satellites per year mark for the first time. But no year in the past compares to 2021. As of Sept. 16, roughly 1,400 new satellites have already begun circling the Earth, and that will only increase as the year goes on. Just this week, SpaceX deployed another 51 Starlink satellites into orbit.

The ever-shrinking size of technology has led to tiny satellites like the one students are working on here. Edwin Aguirre/University of Massachusetts Lowell, CC BY-ND

Small satellites, easy access to orbit

There are two main reasons for this exponential growth. First, it has never been easier to get a satellite into space. For example, on Aug. 29, 2021, a SpaceX rocket carried several satellites – including one built by my students – to the International Space Station. On Oct. 11, 2021, these satellites will deploy into orbit, and the number of satellites will increase again.

The second reason is that rockets can carry more satellites more easily – and cheaply – than ever before. This increase isn’t due to rockets getting more powerful. Rather, satellites have gotten smaller thanks to the electronics revolution. The vast majority – 94% – of all spacecraft launched in 2020 were smallsats – satellites that weigh less than around 1,320 pounds (600 kilograms).

The majority of these satellites are used for observing Earth or for communications and internet. With a goal of bringing the internet to underserved areas of the globe, two private companies, Starlink by SpaceX and OneWeb together launched almost 1,000 smallsats in 2020 alone. They are each planning to launch more than 40,000 satellites in the coming years to create what are called “mega-constellations” in low-Earth orbit.

Several other companies are eyeing this US$1 trillion market, most notably Amazon with its Project Kuiper .

Large satellite constellations – like SpaceX’s Starlink, seen in the video above – are set to dramatically increase the number of objects orbiting Earth and are already causing problems.

A crowded sky

With the huge growth in satellites, fears of a crowded sky are starting to come true. A day after SpaceX launched its first 60 Starlink satellites, astronomers began to see them blocking out the stars. While the impact on visible astronomy is easy to understand, radio astronomers fear they may lose 70% sensitivity in certain frequencies due to interference from satellite megaconstellations like Starlink.

Experts have been studying and discussing the potential problems posed by these constellations and ways the satellite companies could address them . These include reducing the number and brightness of satellites, sharing their location and supporting better image-processing software.

As low-Earth orbit gets crowded, concern about space debris increases, as does a real possibility of collisions.

Future trends

Less than 10 years ago, the democratization of space was a goal yet to be realized. Now, with student projects on the Space Station and more than 105 countries having at least one satellite in space, one could argue that that goal is within reach.

Every disruptive technological advancement requires updates to the rules – or the creation of new ones. SpaceX has tested ways to lower the impact of Starlink constellations, and Amazon has disclosed plans to de-orbit their satellites within 355 days after mission completion. These and other actions by different stakeholders make me hopeful that commerce, science and human endeavors will find sustainable solutions to this potential crisis.

Supriya Chakrabarti, Professor of Physics, University of Massachusetts Lowell

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

The spooky and dangerous side of black licorice

 

Black licorice gets its distinctive flavor from licorice root. PicturePartners/Getty Images

Black licorice may look and taste like an innocent treat, but this candy has a dark side. On Sept. 23, 2020, it was reported that black licorice was the culprit in the death of a 54-year-old man in Massachusetts. How could this be? Overdosing on licorice sounds more like a twisted tale than a plausible fact.

I have a longstanding interest in how chemicals in our food and the environment affect our body and mind. When something seemingly harmless like licorice is implicated in a death, we are reminded of the famous proclamation by Swiss physician Paracelsus, the Father of Toxicology: “All things are poison, and nothing is without poison; the dosage alone makes it so a thing is not a poison.”

I am a professor in the department of pharmacology and toxicology and author of the book “Pleased to Meet Me: Genes, Germs, and the Curious Forces That Make Us Who We Are.”

The root of the problem

The unfortunate man who succumbed to excessive black licorice consumption is not alone. There are a smattering of similar case reports in medical journals, in which patients experience hypertension crisis, muscle breakdown or even death. Adverse reactions are most frequently seen in people over the age of 40 who are eating far more black licorice than the average person. In addition, they are usually consuming the product for prolonged periods of time. In the most recent case, the Massachusetts man had been eating a bag and a half of black licorice every day for three weeks.

Glycyrrhiza glabra is a species native to Eurasia and North Africa from which most confectionery licorice is produced. Franz Eugen Köhler, Köhler's Medizinal-Pflanzen via Wikimedia Commons

Licorice is a flowering plant native to parts of Europe and Asia. Its scientific name, Glycyrrhiza, is derived from the Greek words “glykos” (sweet) and “rhiza” (root). The aromatic and sweet extract from its root has long been used as an herbal remedy for a wide variety of health maladies, from heartburn and stomach issues to sore throats and cough. However, there is insufficient evidence to support that licorice is effective in treating any medical condition.

Glycyrrhizin (also called glycyrrhizic acid) is the chemical in black licorice that gives the candy its signature flavor, but it also leads to its toxic effects.

Glycyrrhizin mimics the hormone aldosterone, which is made by the adrenal glands when the body needs to retain sodium and excrete potassium. Sodium and potassium work together as a kind of cellular battery that drives communication between nerves and the contraction of muscles. Too much glycyrrhizin upsets the balance of these electrolytes, which can raise blood pressure and disturb the heart’s rhythm. Other symptoms of excessive licorice intake include swelling, muscle pain, numbness and headache. Examination of the man who died from consuming too much licorice revealed that he had dangerously low levels of potassium, consistent with glycyrrhizin toxicity.

It should be noted that a number of licorice-based foods do not contain real licorice, but use a flavoring substitute called anise oil, which does not pose the dangers discussed here. In addition, despite its name, red licorice rarely contains licorice extract. Instead, red licorice is infused with chemicals that impart its cherry or strawberry flavor.

Products that contain real licorice are usually labeled as such, and list licorice extract or glycyrrhizic acid among the ingredients. Be advised that some products, such as black jelly beans or Good & Plenty, are mixtures of different candies that contain both anise oil and licorice extract.

Red licorice is sickly sweet but safe to eat. Darren Boucher/Getty Images

Hidden dangers that increase risk

Glycyrrhizin has the distinct licorice flavor and is 50 times sweeter than sugar and has been used in other types of candy, soft drinks, tea, Belgian beers, throat lozenges and tobacco. This can make it challenging to keep track of how much glycyrrhizin has been consumed, and a combination of these products could trigger adverse effects.

Some people take dietary or health supplements that already contain licorice, which increases the risk of toxic effects from eating black licorice candy. Certain medications such as hydrochlorothiazide are diuretics that cause increased urination, which can lower potassium levels in the body. Glycyrrhizin also lowers potassium levels, further disrupting the balance of electrolytes, which can produce muscle cramps and irregular heart rhythms.

People with certain preexisting conditions are more susceptible to black licorice overdose.

For example, patients who already have low potassium levels (hypokalemia), high blood pressure or heart arrhythmia are likely to have greater sensitivity to the effects of excessive licorice. Those with liver or kidney deficiencies will also retain glycyrrhizin in their bloodstream for longer times, increasing their risk of experiencing its adverse effects.

What to do?

If you’re a fan of black licorice, there is no need to ban it from your pantry. Eaten in small quantities from time to time, licorice poses no significant threat to otherwise healthy adults and children. But it is advisable to monitor your intake.

With Halloween approaching, be sure to remind your kids that candy is a “sometimes food,” especially the black licorice. The FDA has issued warnings about the rare but serious effects of too much black licorice, advising that people avoid eating more than two ounces of black licorice a day for two weeks or longer. The agency states that if you have been eating a lot of black licorice and experience an irregular heart rhythm or muscle weakness, stop eating it immediately and contact your health care provider.

Some scientists have further cautioned against the routine use of licorice in the form of a dietary supplement or tea for its alleged health benefits, including the treatment of cough associated with COVID-19 or other respiratory infections. A review article from 2012 warned that “the daily consumption of licorice is never justified because its benefits are minor compared to the adverse outcomes of chronic consumption.”

Article updated to mention concerns about using licorice as a COVID-19 treatment.

Bill Sullivan, Professor of Pharmacology & Toxicology; author of Pleased to Meet Me: Genes, Germs, and the Curious Forces That Make Us Who We Are, Indiana University

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

Diagnoses of doom mask denial about real problems facing South Africa

 

South African president and leader of the ruling ANC Cyril Ramaphosa. Michele Spatari/NurPhoto via Getty Images

To understand South Africa today, we need to recognise that people can focus endlessly on a country’s problems but still live in a state of denial.

Hand-wringing about problems which are said to spell the doom of South Africa’s negotiated democracy is a well-established custom. It began only months after the first election in which all adults could vote in 1994. It has become louder over the past decade and dominates the national debate, which is the preserve of the minority who enjoy access to media.

Right now, violence in the KwaZulu Natal province, attacks on the judiciary by former president Jacob Zuma and his supporters, and an unemployment rate of 34% are the immediate causes of dismay.

But, while the issues change, claims that the country is in deep trouble are routine.

Despite this, the national debate – which is restricted to an elite comprising around a third of the population – is in denial.

How can this be?

The debate’s diagnoses of doom denounce what works in post-1994 South Africa while ignoring or misrepresenting the stubborn and very real problems which prevent democracy from realising its potential. In particular, blaming the governing African National Congress (ANC) has become a substitute for facing deep-rooted problems which would remain whoever governed.

How the denial works

To illustrate how this type of denial works, the three problems which are currently in focus are all real – but far too real to be blamed only on some politicians.

The violence was a result of an incomplete journey to democracy, which means that the security forces are deeply factionalised and that corrupt networks will use violence to protect their turf.

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Read more: Violence in South Africa: an uprising of elites, not of the people

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Yet it is blamed purely on police incompetence or poverty. And the ANC is blamed for both.

The attacks on judges are treated with alarm despite the fact that they are no threat to the constitutional order. They have little credibility in the national debate because they are clearly ploys by politicians desperate to escape prosecution for corruption. Their credibility is further undermined by the fact that those who denounce the judges never hesitate to use the courts when this suits them.

But a real threat to the justice system which has been evident for years – in which grassroots citizens whose living areas are plagued by violence are impatient with due legal process and the courts – is hardly noticed in the now routine rush to blame ANC politicians.

The unemployment figures have prompted much denunciation of the government. But there was no similar reaction in 2003 when the rate was 31%. This went unnoticed because the economy was doing well for the minority able to benefit from it. Since they dominate the debate, it simply ignored reality.

Nor has anyone pointed out that unemployment has been growing for 50 years and that the lowest jobless numbers of the past two decades were higher than those in the Netherlands during the Great Depression.

The debate is in denial over the reality that unemployment is a deep-rooted and long-standing problem.

The denial does not necessarily target the governing party directly. So, a prominent theme is criticism of the political system despite the fact that it works largely as it meant to for the minority whose voices are heard.

Moves are afoot to change the electoral system “to ensure more accountable government”, despite the fact that local government already has the system to which the debate wants to move and is widely agreed to be a site of very little accountability.

A set of hearings at the commission of inquiry into Zuma-era corruption began a pattern in which parliament is said to be defective because it did not hold the ANC to account. The search is on for legal fixes which will force it to do what the one-third who take part in the debate want. Secret ballots are demanded for parliamentary votes in the hope that legislators will do what the debate wants, not what the parties for whom citizens voted want.

None of the proposed changes would make democracy work better – most would weaken it. Changing to an electoral system used by deeply unpopular municipalities will solve nothing; encouraging legislators to hide from voters when they cast ballots will strengthen elites and weaken the citizenry.

The whole point of parliaments is that they give the power to make decisions to the party which wins a majority. Rules to curb that will take the country back to minority rule, not forward to a brighter future. South African democracy works well for those who can make themselves heard – so well that, in a country where it was once common to fear that the ANC would control too much, it is routinely denounced by anyone who wants to be taken seriously by the debate.

Why this frenzy to fix what is not broken? Because the political system will not satisfy the debate as long it allows the ANC to govern. Supporters of a changed electoral system claim it would weaken “party bosses”. So do those who want to force parliament to do what they want and those who want legislators to be allowed to cheat on their voters.

In all three cases, “party bosses” is code for the leadership of the governing party.

Facing deep-rooted problems

The key point here is not that the ANC should not be held to account. Trying to ensure that the governing party does what citizens want it to do is a core feature of democracy. Voters being rude about the governing party is a democratic habit.

The ANC has much for which it should be forced to account: it did not create most of the patterns for which it is blamed, but has done far too little to change them and often seems happy simply to live with them.

But there is a huge difference between holding a governing party to account and making it an excuse for failing to face deep-rooted problems. Fixating on the ANC has given the one-third an excuse not to face difficult realities.

South Africa is a country beset by many problems, only one of which it solved in 1994 – the fact that 90% of the population were denied citizenship rights. Its problems routinely create crises which could be opportunities to face deep-rooted problems. But the opportunities are routinely wasted by a national debate which finds blaming a political party and its current leaders a convenient way of ducking responsibility for tackling these realities.

As long as that continues, the problems will persist because the prospect of tackling them will be drowned out by angry denial.

Steven Friedman, Professor of Political Studies, University of Johannesburg

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

Unpacking South Africa’s excess deaths. What is known and where the gaps are

 

A pop-up site in Johannesburg aimed at encouraging mini-bus taxi operators and commuters to vaccinate on site. Luba Lesolle/Gallo Images via Getty Images

In the 2000s experts from the University of Cape Town and the South African Medical Research Council built a system to track AIDS mortality on a monthly and a yearly basis, using data from the Department of Home Affairs. In 2020 researchers built on this system to track COVID-19 deaths in South Africa. Now, South Africa is one of few countries in the developing world that have managed to build a near-real time mortality tracking system. The South African Medical Research Council publishes a weekly report on deaths in the country. The Conversation’s Ina Skosana spoke to demographer Tom Moultrie about what the data shows.

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Who, according to your figures, is dying, and where are they?

The weekly mortality report provides information on deaths registered in almost real-time on the National Population Register. These are used to determine the actual number of deaths that have occurred in the country and calculate the number of excess deaths over and above the numbers that would be expected had the historical mortality trends before the COVID-19 pandemic continued.

In South Africa between May 2020 and early September 2021, over a quarter of a million more people have died from natural causes than was predicted for that time period.

The vast majority – three quarters – are over the age of 60.

The burden of this has been very heavily felt by those at older ages. But it is not completely unaffecting those aged under 60. And that is because of the high prevalence of noncommunicable diseases. South Africa has a high incidence of diseases and conditions such as diabetes, hypertension and obesity. These are all known cofactors for COVID-19 related mortality

The geography of where people are dying is largely a reflection of where people are living. The actual count of excess deaths is lower in the sparsely populated Northern Cape than more densely-populated provinces such as the Western Cape or Gauteng. Allowing for population size and age-distribution, the three most-affected provinces are the Northern Cape, KwaZulu-Natal, and the Eastern Cape; while the three least-affected provinces are the Western Cape, North West, and Gauteng.

What are the leading causes of death?

This is the real problem we have with trying to understand COVID-19 deaths in the country. We get the data we use from the Department of Home Affairs, which only classifies deaths by natural or unnatural causes.

Unnatural causes of death would be homicides, suicides and accidents. Natural causes refers to medical causes of death.

At the time of death, a doctor or medical attendant records the chain of causes leading to death on an official death notification form. But that information is not captured in real time by the Department of Home Affairs. This data is only released by Statistics South Africa many years after the fact. For example, the mortality and causes of death report release in 2021 reflects deaths recorded through to 2018. However, the actual data are still only available through to 2017.

The numbers reported by the national Department of Health every night reflect those known to have died from COVID-19 and who were known to have been infected with the virus. But those reports miss many deaths, especially of those who do not die in a health facility.

In the meantime, however, we can look at the proportions of people testing positive, the excess deaths (above what was expected) as well as the officially reported COVID-19 deaths to get a sense of how these relate to each other. The estimates of excess deaths produced every week show that the peaks of the excess deaths follow almost exactly the peaks of reported COVID-19 deaths, as well as the cases reported a week or so earlier.

The South African Medical Research Council and University of Cape Town collaboration, who produce the estimates of excess deaths every week, has come to the view that between 85% and 95% of the excess natural deaths in the country are related to COVID-19.

But we do not know for certain. That’s one of the great tragedies of vital registration systems in sub-Saharan Africa and the developing world generally.

How can this information be used in the COVID-19 response?

The excess deaths shows that the effects of COVID-19 are far more severe than that reflected in the national data. We can see that even at a more granular level by looking at the provincial data. The number of COVID-19 deaths reported in the Western Cape – which has the best-functioning health data system in the country – is about 70% of the number of excess deaths estimated for the province. Based on this information we can be fairly certain that other provinces are missing COVID-19 deaths.

But even if we can’t attribute all of those excess deaths to COVID-19, we can say with a high degree of certainty that a lot more people have died from COVID-19 than has been reported by the National Department of Health.

Another thing that we’ve managed to do during this period of repeated lockdowns and changes in regulations has been to try and tease out the effects of the various alcohol bans and curfews on the number of unnatural deaths. Unnatural deaths – as a consequence of homicide, suicide, and accidents – tend to be strongly associated with alcohol. And one of the things which we have managed to show in the paper, which we published in the South African Medical Journal, was exactly how extreme the effects of banning alcohol are in terms of their impacts on the number of unnatural deaths. We also showed that the partial restrictions on the sale of alcohol are largely ineffective.

So this data contributes to the evidence base which government can draw on to determine what their COVID-19 response should be.

Tom Moultrie, Professor of Demography, University of Cape Town

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

How poverty and violence are linked with anxiety in young South Africans

 

Young people living in urban informal settlement are exposed to high levels of violence and poverty. Darren Stewart/Gallo Images via Getty Images

Over the past 10 years there has been increasing awareness of the importance of promoting good mental health in South Africa. Most of the mental health awareness campaigns have been around depression, suicidal thoughts and suicide, and alcohol abuse.

Important and often overlooked forms of poor mental health are anxiety disorders. The most recent estimates of anxiety disorders in South Africa are from a 2009 nationally representative study. Anxiety disorders were the most common form of poor mental health reported by South Africans in the research. More than 8% reported anxiety disorder in the past year. Anxiety disorders include agoraphobia, which is the fear of places or situations that may cause embarrassment, as well as panic attacks. A broader form of anxiety is generalised anxiety disorder. It manifests itself as ongoing generalised worry.

This worry can be about many things – from money to how to provide for children and hopes for the future. Such generalised anxiety is associated with increased substance misuse, greater risk of acquiring HIV, as well as other mental health disorders. It may also reduce people’s economic well-being through limiting their ability to look for work, or go out and work.

Studies globally have broadly identified two main structural drivers of anxiety: poverty and violence.

In South Africa half of adults are living below the poverty line, defined as earning an income of less than R1,183 per month. Similarly, experiences of violence in childhood and later life are common. A study among 15-17-year olds found that 10% of boys and 15% of girls had experienced sexual violence in their lifetime. Violence and injuries are the second leading cause of lost disability-adjusted life years in South Africa.

Yet the challenges of poverty, violence and chronic stress experienced by many South Africans daily and for many years are not uniform. Young people, particularly those living in the challenging contexts of urban informal settlements, may be more at risk of experiencing generalised anxiety disorder. This is because poverty and community violence are more common in these spaces than in other communities.

Few studies look at anxiety. But it remains the most common form of mental health disorder in South Africa.

Understanding the causes is important for starting to understand how to address generalised anxiety disorders. In our recent research we spoke to young people living in informal settlements in eThekwini Municipality, in KwaZulu-Natal. We asked them about their symptoms of anxiety, as well as potential risk factors for anxiety. These included abuse in childhood, interpersonal violence, food insecurity and stress related to poverty.

Symptoms of generalised anxiety disorder were higher in respondents who reported experiencing particularly extreme levels of poverty and experiencing violence. Addressing these two factors is critical for reducing poor mental health and its future impacts on individuals and potentially their children.

Anxiety in urban informal settlements

Our study was conducted in 2018. The study participants were young women and men (ages 18-30) who were already part of an intervention trial called Stepping Stones and Creating Futures. This intervention was run by the South African Medical Research Council and Project Empower, and sought to reduce poverty and violence among young people living in urban informal settlements.

We asked the respondents (488 women and 505 men) about their own experiences of symptoms related to generalised anxiety disorder. These are symptoms such as feeling nervous, not being able to stop worrying and being restless. In our study we found a high rate of women and men reporting moderate or severe symptoms of generalised anxiety disorder – 18.6% and 19.6%, respectively – as assessed through seven questions which comprised the Generalised Anxiety Disorder 7 Scale.

We asked women and men a range of questions about their experiences of poverty, violence and stress. We also looked at multiple potential risk factors for anxiety. Women with more severe symptoms of generalised anxiety disorder, as compared to those with few symptoms, were more likely to have stolen because of hunger in the past month, and be stressed about lack of work. They were also likely to have experienced more adverse events such as witnessing the death of someone or being robbed at knife or gunpoint, and to have experienced violence from a partner in the past year.

For men, a similar pattern to women was seen. More severe generalised anxiety disorder symptoms were associated with poverty and experience of violence. Specifically, men with more anxiety symptoms, as compared to those with fewer symptoms, had stolen in the past month because of hunger, reported more adverse experiences as children, and had more adverse experiences in adulthood.

Addressing anxiety in South Africa

Our findings show how poverty, experiences of violence and adverse events are key contributing factors for generalised anxiety disorder among young people living in urban informal settlements.

South Africa must address the wider structural drivers of poor mental health, specifically poverty, unemployment and violence. It is the only way to achieve the Sustainable Development Goals, and specifically Goal 3.4, which emphasises the need to promote mental health and well-being.

Andrew Gibbs, Senior specialist scientist: Gender and Health Research Unit, Medical Research Council, South African Medical Research Council

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