The universe is a place that is violent to us at times, particularly because it is constantly dealing with amounts of energy beyond our daily experience. The discovery of events that end up in the newspaper headlines is not that common, only those where we can give superlatives to what is measured, be it the brightest, the closest, or that which is discovered for the first time.
For example, a few days ago the press reported the discovery of a Type II supernova, SN 2023ixf, one of those formed by the collapse of massive stars. That’s because it has all the ingredients that make it interesting to the general public: It’s the closest object to Earth to be spotted in almost a decade, and the first to see it was a Japanese amateur astronomer, Koichi Itagaki, who she also discovered 80 of them. in his observatory in the mountains of the city of Yamagata. But today we are not here to report the news, we are going to talk about another type of explosion, that of Type Ia supernovae, which, because they are all the same, allow us incredible measurements in the cosmos. Forget your famous cousins, black holes or Type II supernovae, we’re here today to talk about masses and white dwarfs.
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Believe it or not, the smallest existing stars, which can be as small as a moon, are responsible for the most energetic explosions in the universe. These stars are, on average, the size of Earth, but since they are nearly the mass of the Sun, their gravity is 10,000 times greater. Because white dwarfs are small and nuclear reactions no longer take place inside, they are, like all small things, difficult to see. There are very faint objects in the sky. In fact, although there are many, they are not only the most common product, but also one of the most spectacular of star formation. But it’s also curious that we don’t know exactly how the spark that causes their detonation occurs when they are in pairs.
White dwarfs are used both to detect the existence of dark energy and to measure distances on cosmological scales, as well as to determine the chemical composition of asteroids. The coldest ones could be almost as old as the universe. Like the Earth’s core, they are coated with chemical elements inside by gravity, and their atmosphere is so clean that we can use it to accurately measure the chemical composition of rocks that fall onto their surface. And if all of that isn’t fascinating enough, just know that a spark can cause them to explode in explosions so spectacular they can even be seen in galaxies far away.
The smallest stars, as tiny as a moon, are responsible for the most energetic explosions in the universe. It is strange that we do not know how it detonates
Produced from NASA’s Chandra Observatory recordings of a supernova that exploded in the 16th century.NASA
Inside, the material behaves in a very special way, for example you can increase its pressure without increasing its temperature and that’s something quite unusual for what we’re used to, they don’t behave like almost all the gases that surround us . , which are perfect or ideal gases. And since they aren’t hot enough to ignite the next nuclear fuel, a white dwarf isn’t actually a star (or a regular star), but defined precisely by that source of energy.
These stars have densities more than a billion times that of the air in the atmosphere. They are also the only stars that can crystallize. Their structure is almost always carbon and oxygen, having rid themselves of everything else in their previous lives, creating the spectacular structures we know as planetary nebulae.
Its size is determined by quantum mechanics and it is Heisenberg’s uncertainty principle that can broadly explain its structure. The electrons are very packed, so their positional variation is very small, which means their momentum (mass times velocity) is very large. Since the electrons have a low mass, they must have a very high velocity, which creates the pressure that prevents the star from collapsing. The more mass a white dwarf has, the smaller it is.
But let’s get to the explosions: We can say that they are the most violent in the universe, releasing 1,041 KJ of energy (a plate of lentils contains about 300 KJ) in about one second (that’s about 18 orders of magnitude more energy than). what the sun emits in a second) and I refuse to equate it with the infamous TNT or atomic bombs. At their highest light emission, Type Ia supernovae are brighter than all the stars in a galaxy combined. Therefore we can measure them over long distances.
Type Ia supernovae are the most violent explosions in the Universe, releasing 1,041 KJ of energy in one second (about 18 orders of magnitude more energy than the Sun); brighter than all the stars in a galaxy combined at their highest light emission
A supercomputer generated visualization emulating a Type Ia supernova detonation. BRAD GALLAGHER (UNIVERSITY OF CHICAGO)
The conditions of the explosion are so extreme that it is very difficult to explain the physical processes involved from a computational point of view, so our understanding of these events is still very limited. For example, we don’t have a clear idea of what triggers the explosion, i.e. what ignites the fuse? The two mechanisms we think might be responsible are related to the existence of a companion star: either the companion adds mass to the white dwarf until it crosses a boundary that causes it to explode, or two white dwarfs arrive so close that they eventually merge.
For now, let’s think of this extremely violent explosion as the beginning, not the end, as the process converts carbon and oxygen into heavier elements and involves energy and temperature scales well beyond our everyday experience. The nickel from chocolate and spinach was produced in one of those cataclysmic events in these amazing stars.
Cosmic Void is a section that qualitatively and quantitatively presents our knowledge of the universe. It is intended to illustrate how important it is to understand the cosmos not only from a scientific point of view, but also from a philosophical, social and economic point of view. The name “cosmic vacuum” refers to the fact that the universe is mostly empty and there is less than one atom per cubic meter, although paradoxically in our environment there are trillions of atoms per meter cubic, which invites us to wonder about our existence and contemplating the presence of life in the universe. The section consists of Pablo G Perez GonzalezResearchers at the Center for Astrobiology, and Eva VillaverResearch Professor at the Instituto de Astrofísica de Canarias.
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