What’s a Black Hole?

– January 30, 2020 – Science

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  • What is a black hole?

Black holes are among the most impressive and fascinating objects in the universe. Scientists are trying to unravel their mysteries, even though they are invisible and often unpredictable. What’s a black hole made of?

A black hole was imaged for the very first time in 2019. This breakthrough, awaited by scientists, was particularly well-publicized. The ring of fire that stands out against the black background of this first photo reminded us how fascinating and mysterious black holes are, and how much astronomers still have to learn about them.

But what exactly is a black hole? What are the different types of black holes known? Can a black hole die? Is the Earth in danger of crossing a black hole? Here’s what you need to know about these unpredictable astronomical objects.

A black hole is not a vacuum

Although its name might suggest it, a black hole is not a place in space that would be empty. On the contrary, a black hole is a region of space where a very large amount of matter accumulates. To imagine a black hole, we can for example imagine the mass of a star, 10 times more massive than our own Sun, which would be contained in a sphere the diameter of the city of New York, says NASA.

A black hole has a gravitational field so intense that no matter entering it can escape, including light. That’s why black holes are optically invisible objects. Material caught in a black hole, on the other hand, can be detected because it is heated to very high temperatures. This material forms an accretion disc, which looks like a luminous halo on the only black hole photo ever made. The accretion disc rotates (but the black hole itself does not necessarily rotate).

  • To be read : The first photographed black hole emits a jet that almost defies the speed of light.

YouTube Unveiled Screenshot

A black hole, artist’s rendering. // Source: YouTube Unveiled Screenshot

What are the different types of black holes?

Black holes are usually distinguished from each other by their mass.

  • Stellar black holes: they generally represent between 10 and 24 times the mass of the Sun.
  • Supermassive black holes: these are giant black holes, whose mass is at least one million times that of the Sun. They can be even more imposing: a black hole of 40 billion solar masses has been measured. M87*, the black hole that was photographed, is also a supermassive black hole.
  • Intermediate black holes: as their name indicates, they are halfway between stellar black holes and supermassive black holes. Their mass would be a few thousand times that of the Sun. Their existence has yet to be irrefutably proven: scientists have proposed to use the “symphony” of their waves to try to detect them.

How do black holes form?

It is accepted that stellar black holes are born when a star collapses on itself. This star must be massive enough to form a black hole: our Sun could not become one, for example. To form a stellar black hole, the residual core left by the star must be greater than three solar masses.

  • To be read : An “impossible” black hole in the Milky Way? New questions surround the discovery

The formation of supermassive black holes is the subject of scientific debate. It can be assumed that the formation of these giant black holes takes place on long time scales, given their size. Yet we know that supermassive black holes were already present in the still young universe. These objects could not form by star accretion (by “swallowing” star matter, which allows them to grow).

The formation of intermediate black holes would be explained by a chain reaction: a collision of stars located in very dense clusters, which would lead to an accumulation of very massive stars. Their collapse would give rise to intermediate-mass black holes. The fusion of intermediate black holes could even give rise to supermassive black holes.

  • To be read : A new class of small, hidden black holes may have been discovered

What’s inside a black hole?

Even if it is strongly discouraged to visit a black hole (NASA recalled it in a much too cute video), one can wonder what is inside these strange objects. To know this, one would have to be able to cross the “boundary” of the black hole (in the geometric sense, because it is not a membrane) which is called the event horizon. This is precisely the point of no return beyond which no element entering the black hole can emerge.

If you could fall into a black hole and see what’s there, what would happen? You probably wouldn’t have time to see much because you would be stretched like a spaghetti (scientists call it spaghettification). Since nothing escapes a black hole, it is not possible to know what is at the centre of this object, in what is called its singularity.

Can a black hole die?

Stephen Hawking highlighted a paradox: black holes are not totally black holes because they emit particles and can evaporate, until they disappear completely. This phenomenon occurs in the form of radiation, called Hawking radiation.

Because of this radiation, black holes have a limited lifespan. Nevertheless, for some black holes, the time it would take for them to completely evaporate is more important than the age of the universe.

Should we be afraid of black holes?

The fate of stars caught in black holes (or that of that lucky star that was expelled from the black hole in the Milky Way) may raise fears that one day our planet will cross the path of a black hole. Yet the danger is elsewhere.

  • To be read : What would happen if the Earth was sucked into a black hole?

If anything should frighten us, it is not the encounter with a black hole, but the encounter with another star. It is much more likely to cross the path of a star (the most common star in our galaxy) than that of a black hole.

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Julien Lausson – January 30, 2020 – Tech

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  • Universal charger standard urgently needed, says European Parliament

The European Parliament wants the Commission to formulate measures by July 2020 to achieve a truly universal charger. The subject has been going on for more than ten years.

The result is irrevocable and reflects the impatience of the Old Continent. On Thursday 30 January the European Parliament overwhelmingly supported (582 votes in favour, 40 against and 37 abstentions) a resolution calling on the new Commission chaired by Germany’s Ursula von der Leyen to take urgent regulatory measures – thus binding on the industry – to finally achieve a universal charger for all portable devices.

For parliamentarians, it is time for the legislator to make up for the inability of industrialists to agree on a common device, which could be used for all small and medium-sized devices (from smartphones to tablets, cameras, reading lights or mobile phones to mention only the most common product categories).

Admittedly, admitted MEPs, voluntary agreements between industry stakeholders have “significantly reduced the number of charger types in themarket” over the past decade or so, as discussions on the subject began in 2009, at a time when the Samsung Galaxy iPhone 3GS and other HTC G1 Dreams were in vogue. An eternity, therefore, in the world of telephony.

At the time, several manufacturers had signed a memorandum of understanding was signed (among them were Apple, LG, Nokia, Motorola, Nokia and Sony Ericsson) to develop a common charger. It was due to arrive in 2011, based on micro-USB connectivity. After the expiry of the MOU in 2012, some companies continued their commitment through letters of intent in 2013 and 2014.

Chris-Håvard Berge

Reflection on the universal charger dates back to 2009, when the iPhone 3GS was released. // Source: Chris-Håvard Berge

However, the elected officials note that the public is “always having to deal with different types of chargers on themarket” which, given the relatively high turnover of equipment among the general public, unnecessarily leads to the generation of additional e-waste, which could be reduced if a common basis were adopted.

Beyond convenience, therefore, there is an environmental issue: in Europe in 2016, the total production of electronic waste amounted to 12.3 million tonnes, or an average of 16.6 kg per person. This share could be reduced if the loaders could feed more products: not only would they be trashed less, but it would also be possible to produce less of them.

Challenges for Europe and the environment

Moreover, this is one of Parliament’s requests: to make the charger optional when purchasing any electronic device. “Strategies to decouple the purchase of chargers from the purchase of new devices should be introduced with a universalcharging solution,” argue the elected officials. But beware: all this must be done without any price increase for customers.

The resolution adopted today has no binding legal force, but it calls on the European Commission to look at where its interest lies: ” it is essential for the credibility of the European Union in the eyes of its citizens and on the international stage that legislative acts adopted by the Union are transposed in good time by concrete legislative measures“, observes Parliament.

Mauro Bottaro/ <a href=European Union 2019′ class=’wp-image-15723′ data-lazy-sizes='(max-width: 1024px) 100vw, 1024px’ data-lazy-src=’https://verifiedtasks.com/wp-content/uploads/2020/02/mauro-bottaro-european-union-2019.jpeg’ data-lazy-srcset=’https://verifiedtasks.com/wp-content/uploads/2020/02/mauro-bottaro-european-union-2019.jpeg 1024w, https://verifiedtasks.com/wp-content/uploads/2020/02/mauro-bottaro-european-union-2019-300×170.jpeg 300w, https://verifiedtasks.com/wp-content/uploads/2020/02/mauro-bottaro-european-union-2019-768×434.jpeg 768w, https://verifiedtasks.com/wp-content/uploads/2020/02/mauro-bottaro-european-union-2019-800×452.jpeg 800w, https://verifiedtasks.com/wp-content/uploads/2020/02/mauro-bottaro-european-union-2019-600×339.jpeg 600w, https://verifiedtasks.com/wp-content/uploads/2020/02/mauro-bottaro-european-union-2019-696×394.jpeg 696w, https://verifiedtasks.com/wp-content/uploads/2020/02/mauro-bottaro-european-union-2019-743×420.jpeg 743w’ height=’579′ src=’data:image/svg+xml,%3Csvg%20xmlns=’http://www.w3.org/2000/svg’%20viewBox=’0%200%201024%20579’%3E%3C/svg%3E’ width=’1024’>

Margrethe Vestager, Commissioner for Competition, who has been following the case for some years. // Source: Mauro Bottaro/ European Union 2019

In 2018, Competition Commissioner Margrethe Vestager, who has since been reappointed, stated that “in view of the unsatisfactory progress of this voluntary approach, the Commission will shortly launch an impact assessment to evaluate the costs and benefits of various otheroptions”. Clearly, things have skated since then.

Finally, on the periphery of this issue, Parliament wants the Commission to promote the interoperability of wireless chargers with different portable devices and to look into legislative initiatives that will improve the collection and recycling of chargers on the continent. Brussels is invited to formulate its proposals by July 2020 at the latest. Six months from now, then. But it’s been dragging on for ten years.




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