​Our children will see fewer and fewer stars in the night sky ● Why do people tend to have increasingly brittle bones? ● The collapse of the ice sheets is much closer than predicted

Our children will see fewer and fewer stars in the night sky

The stars begin to gradually disappear from the night sky, and over time they become fewer and fewer. It’s a process that began over two hundred years ago, and no, the starlight didn’t suddenly disappear. We just can’t see it anymore.

In fact, a child born today, at the age of 18, will see only 100 stars for every 250 visible today. And this is because of light pollution, which has increased and is increasing by an average of 9.6% every year. Another factor that increases the brightness of the sky is the increase in the number of satellites and space debris that reflect sunlight.

As urbanization has accelerated over the last century, more artificial light sources have appeared, and more satellites have been launched, the night sky has become brighter, and the stars have implicitly begun to fade from view. .

Data collected from satellites suggests that light pollution levels in Europe and North America have stagnated over the past decade. But it has grown significantly in Asia, South America and Africa, so that the phenomenon has reached the specified parameters. Even so, the satellites do not see blue light from LEDs, the most important source of light pollution, which means that the data they provide is even less than what is provided.

Little can be done, and it is hard to imagine that steps will be taken to reduce light pollution. LEDs should be replaced with more yellow light sources, public lighting should be controlled by sensors, or artificial light sources should be equipped with screens that direct light only downwards.

But humanity has much bigger problems right now, so we’ll have to get used to that thought. That is, from year to year we will see fewer and fewer stars.

Why do people tend to have increasingly brittle bones?

While conducting a study on the risk of osteoporosis in postmenopausal women, several researchers from Columbia University in New York had an unpleasant surprise. And that’s because many of the 9,041 women monitored had bone density drop twice as fast as the natural aging process would allow.

Further analysis showed that there is a relationship between the degree of air pollution and a decrease in bone density. More precisely, the aforementioned specialists measured the level of pollution in the territories where the observed people lived, and compared the obtained data with previous medical data.

It was found that a three-year exposure to air pollution of only 10% leads to a loss of bone density of the whole body by 1.22%, including the spine and hips. The process is known as oxidative stress, premature aging of the body, particularly bones, as a result of the action of toxic molecules.

As mentioned, the study only looked at menopausal women, so researchers say more data is needed to clearly show how air pollution affects different age groups, social groups or different ethnic groups. So far, similar studies have only been conducted in Asia and Spain, and all have produced similar results regarding the link between air pollution and the risk of fractures or osteoporosis.

The collapse of the ice sheets is much closer than expected

The melting process of the Antarctic and Greenland ice sheets is very close to reaching the point of no return, several scientists from South Korea and the United States of America say. And that point will be reached even if humanity somehow manages to stop global warming at a peak of just 2 degrees Celsius, as outlined in the Paris Agreement.

According to experts’ calculations, the point of no return will be reached if the global temperature rises by 1.8 degrees. They also reported that it is necessary to maintain the temperature below 1.5 degrees so that the process does not become catastrophic.

Computer models have shown that sea and ocean levels will rise by at least one meter over the next 130 years, causing a population migration of biblical proportions, while many of the world’s major urban settlements are located in coastal areas.

Cairo, Mumbai, Shanghai, New York, Los Angeles, London or Buenos Aires are just some of the cities that will be affected, and the consequences of the expected changes are still far from being fully understood. Now, after telling us about it in their study in Nature Communications, scientists say there is more to do, but that action must be urgent and effective.

But that’s what everyone says. If we look at what is happening around us, it is harder to remain optimistic.

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