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» Glavni naslovi






RADIATION, Dangerous and useful

The term radiation or radiation (lat. radius - ray) implies the emission of radiation or particles from a source. Radiations of very high energy, which are able to directly or indirectly create ions, are called ionizing radiations. Ionizing radiations are the main cause of protoplasm "injuries" that occur in the matter that absorbs them. These radiations are produced in nuclear reactions and processes, as well as special laboratory and industrial devices, and are also present in cosmic radiation. Radioactivity is the property of some chemical elements, or matter, to emit invisible particles or rays of high energy.
Radioactivity and radiation were present in the cosmos before the Earth was formed. Physicists have calculated that bursts of gamma radiation caused by large explosions in space may have prevented the development of life in ninety percent of galaxies. Intense radiation is lethal to even the most durable known life forms, and can even remove important gases from the atmosphere. According to the latest measurements, most of the Milky Way is not suitable for life, precisely because of gamma radiation.



Menacing lights in space

Earth regularly collides with matter from space, but these objects are usually too small to cause damage. Previous collisions have shaped Earth's history, from the formation of its satellite to the extinction of species. The probability of an asteroid impact is very low, although these events do occur from time to time, and the damage they cause is great. There are a number of options being explored for collision prevention, but there is still no comprehensive defense system.
Collisions with asteroids, comets and other objects from space are the reasons for key events in the history of our planet: major climate changes, the formation of the Moon, the geological structure of our planet and the extinction of living species. Threats related to asteroid strikes are announced from time to time in the news, but the excitement quickly dies down when the "missiles" bypass us, i.e. pass by us at great distances. Otherwise, as happened with the 2013 Chelyabinsk meteorite in Russia, we don't know they're there until it's too late. What can we do to prevent a collision?



Through space without a spacecraft!

In her recently published paper, Irina K. Romanovskaya, professor of physics and astronomy at Houston Community College, states that people do not need superfast spacecraft for space travel - for these long trips, planets that wander through space and are not bound to the stars can serve. This idea can play an important role in the search for extraterrestrial intelligence because advanced extraterrestrial civilizations, during migrations, can leave visible technological traces on wandering planets. The search for technosignatures of extraterrestrial civilizations can be described as "the search for migrating extraterrestrial intelligence (SMETI)," Romanovskaya points out.
Romanovskaya believes that today's unknown extraterrestrial civilizations can use wandering planets to reach, land, explore and colonize planetary constellations. In the aforementioned paper, she presents possible technosignatures and artifacts of extraterrestrial civilizations on free-roaming planets and lists solutions for long movements in the cosmos.



Return to the Moon

Exactly five decades ago, in December 1972, the last of the 12 astronauts who stayed on the lunar surface during the "Apollo" program, the commander of the ship "Apollo 17" Eugene Cernan said goodbye to the lunar landscape and climbed the ladder to the cabin of the lunar module, entered it and closed the door. A little later, the rocket engine of the take-off section of the lunar module was activated by the pilot Harrison Schmidt and led the module towards the lunar orbit, where the command and service module with which they connected was waiting for them. They went into it with about 110 kg of lunar rock and dust samples and returned to Earth following the same procedure as previous missions.
The "Apollo" program of manned flights to the moon was thus completed. All the participants in that program and numerous scientists around the world then believed that the Apollo 17 flight was only "the end of a beginning" and that new and more advanced programs of flights to the Moon and the establishment of a base-settlement on its surface would follow. However, there was no political will or economic justification for such a thing in the USA at the time, considering the enormously high cost of flights to the moon. Decades followed in which some new projects for the formation of a base on the moon - for example "Lunox" or "First lunar outpost", which were far from being realized - were only occasionally reminded that we should continue on the path traced by the "Apollo" program.
That is why the recently completed and very complex "Artemis 1" mission seemed to be an encouragement to everyone.



Cervical cancer

In the European Cervical Cancer Prevention Week, the public is warned, every year anew, about the danger of a deadly disease that affects too many women, all over the world, but the overriding goal of the campaign is to remind of the ways in which this disease can get in the way. The interlocutor of "Planet" on this topic, Dr. Monika Delon, gynecologist at the Acibadem Bel Medic General Hospital in Belgrade, points out very important information: from the development of the so-called in situ lesion, as a malignant change that is completely curable, to the development of invasive cancer of the cervix, which is in a large number of cases it is fatal, it usually lasts for several, and sometimes up to 10 years. In women who undergo a simple cytological analysis known as a Pap smear, at least once every three years, the risk of developing invasive cervical cancer is reduced by about 10 times. Regular examinations reveal the first, i.e. early, precancerous changes on the cervix, which can then be easily and completely removed.



Inheritance as a basic path

The significance of Darwin's "Origin of Species" is, among other, that he presented such a great amount of evidence for evolution that it subsequently became a generally accepted fact among the majority of the educated public. He collected this evidence for decades and was helped by scientists around the world with whom he was in daily correspondence. His evidence is mostly based on the observation of today's animals and plants, their anatomical structure, way of life and distribution, while paleontological evidence followed mostly only after the publication of his book. But Darwin also saw the shortcomings of his theory and devoted two entire chapters of the book to trying to answer possible objections from readers.
Darwin's book raised new questions and initiated new research in biology, in the field, in nature and in laboratories around the world. Scientists looked for evidence in the living world that evolution really took place. The best evidence for evolution was morphological. Scientists, studying animals, increasingly found rudimentary organs, useless organs whose origin can only be explained by evolution, and by no means God's creation. Evolution explains that these are the remains of organs that were once useful and later lost their function.



Last days and sparks of the future

In just one month, there were two significant anniversaries; on December 5, 2022, the Nikola Tesla Museum marked 70 years since its foundation, and on January 7, 2023, 80 anniversary of the death of the genius scientist and inventor. Although the stories about Tesla's death and funeral, as well as the creation of his museum in Belgrade, are mostly known to the general public, it is particularly interesting to take a look at certain documents and memories of some of the key actors that provide valuable insight into a number of lesser-known details about Tesla's last days, about the Opel , about Tesla's funeral and subsequent cremation, as well as about the fundamental formation of Tesla's entire legacy and its path to the future museum in Belgrade, which will become a unique place in the world and an exceptional testimony of Tesla's life journey and the immeasurable importance of his entire work.
When it comes to important details related to Tesla's last days and numerous facts about the burial and cremation of Tesla's remains, the most precious sources certainly include the memories of Šarlota Mužar, the longtime secretary of Sava Kosanović, the son of Tesla's youngest sister Marica.



Mysterious creatures from
the depths of the sea

For the first sailors, the seas represented an unpredictable, unknown and above all dangerous environment, but also the only way to reach certain areas. It was believed that hidden monsters were lurking in the fathomless depths of the sea. Even the bravest sailors were in awe of the sea, and their stories about encounters with unknown creatures on the open sea were excellent material for folk beliefs and over time became legends. In order for a creature to become the subject of a story that would later be passed down from generation to generation, it was not enough that it was only of exceptional size, but it also had to be associated with attacks on ships and the suffering of the crew.
Among the legends that have survived is one that describes the kraken, a creature from Norse mythology, one of the largest monsters believed to inhabit the depths of the sea. This huge monster, which for hundreds of years represented an indescribable danger to sailors, was believed to reach a size of several kilometers, to sink ships and to love the taste of human flesh! From its first mention, the kraken became a part of Norse mythology and folk beliefs, and according to an ancient Norwegian writing from 1180, it was just one of the many sea monsters encountered by those who sailed the seas.
However, this creature was special in that it was huge in size, as big as an island and capable of sinking ships, and it hunted in the waters between Norway, Iceland and Greenland. Legend has it that this creature could devour the entire crew of a fleet at once!






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