SUPERNOVA, the explosion that marked the death of a star. Sometimes a supernova explosion is brighter than the galaxy in which it occurred.
Supernovae are divided into two main types. Type I is characterized by a deficiency of hydrogen in optical spectrum; therefore, it is believed that this is an explosion of a white dwarf - a star that is close in mass to the Sun, but smaller and denser. There is almost no hydrogen in the composition of a white dwarf, since this is the end product of the evolution of a normal star. In the 1930s, S. Chandrasekhar showed that the mass of a white dwarf cannot exceed a certain limit. If it is in a binary system with a normal star, then its matter can flow onto the surface of the white dwarf. When its mass exceeds the limit of Chandrasekhar, white dwarf collapses (shrinks), heats up and explodes. see also STARS.
A type II supernova erupted on February 23, 1987 in our neighboring galaxy, the Large Magellanic Cloud. She was given the name of Ian Shelton, who first noticed a supernova explosion with a telescope, and then with the naked eye. (The last such discovery belongs to Kepler, who saw a supernova explosion in our Galaxy in 1604, shortly before the invention of the telescope.) Ohio (USA) registered a neutrino flux - elementary particles born at very high temperatures during the collapse of the star's core and easily penetrating through its shell. Although the neutrino stream was emitted by a star along with an optical flash about 150 thousand years ago, it reached the Earth almost simultaneously with photons, thus proving that neutrinos have no mass and move at the speed of light. These observations also confirmed the assumption that about 10% of the mass of the collapsing stellar core is emitted as neutrinos when the core itself collapses into a neutron star. In very massive stars, during a supernova explosion, the nuclei are compressed to even high densities and, probably, turn into black holes, but the outer layers of the star are still being shed. Cm. also BLACK HOLE.
In our Galaxy, the Crab Nebula is the remnant of a supernova explosion, which was observed by Chinese scientists in 1054. The famous astronomer T. Brahe also observed in 1572 a supernova that erupted in our Galaxy. Although Shelton's supernova was the first near supernova discovered since Kepler, hundreds of supernovae in other, more distant galaxies have been spotted with telescopes over the past 100 years.
In the remnants of a supernova explosion, you can find carbon, oxygen, iron and more heavy elements. Therefore, these explosions play important role in nucleosynthesis - the process of formation of chemical elements. It is possible that 5 billion years ago the birth solar system also preceded by a supernova explosion, as a result of which many elements arose that became part of the Sun and planets. NUCLEOSYNTHESIS.
SUPERNOVA
SUPERNOVA, the explosion of a star, in which almost the entire STAR is destroyed. Within a week, a supernova can outshine all other stars in the galaxy. Luminosity over new star 23 magnitudes (1000 million times) greater than the luminosity of the Sun, and the energy released during the explosion is equal to all the energy emitted by the star during its entire previous life. After a few years, the supernova increases in volume so much that it becomes rarefied and translucent. For hundreds or thousands of years, the remnants of the ejected matter are visible as supernova remnants. A supernova is about 1000 times brighter than a NEW STAR. Every 30 years, a galaxy like ours has about one supernova, but most of these stars are obscured by dust. Supernovae are of two main types, distinguished by their light curves and spectra.
Supernovae - unexpectedly flashing stars, sometimes acquiring a brightness of 10,000 million times greater than the brightness of the Sun. This happens in several stages. At the beginning (A), a huge star develops very quickly to the stage when various nuclear processes begin to proceed inside the star at the same time. Iron can form in the center, which means the end of production nuclear energy. The star then begins to undergo gravitational collapse (B). This, however, heats up the center of the star to such an extent that chemical elements decay, and new reactions proceed with explosive force (C). thrown out most of matter of the star into space, while the remnants of the center of the star collapse until the star becomes completely dark, possibly becoming a very dense neutron star (D). One such grain was visible in 1054. in the constellation Taurus (E). The remnant of this star is a cloud of gas called the Crab Nebula (F).
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Books
- The Finger of Destiny (including a full review of the unaspected planets), Hamaker-Zondag K. The book by the famous astrologer Karen Hamaker-Zondag is the fruit of twenty years of work on the study of the mysterious and often unpredictable hidden factors of the horoscope: the Finger of Destiny configurations, ...
Supernova - the explosion of the dying is very big stars with a huge release of energy, a trillion times greater than the energy of the sun. A supernova can illuminate the entire galaxy, and the light sent by the star will reach the edges of the Universe. If one of these stars explodes at a distance of 10 light years from the Earth, the Earth will completely burn out from energy and radiation emissions.
Supernova
Supernovae not only destroy, they also replenish the necessary elements into space: iron, gold, silver and others. Everything we know about the universe was created from the remains of a supernova that once exploded. A supernova is one of the most beautiful and interesting objects in the universe. The largest explosions in the universe leave behind special, strangest remnants in the universe:
neutron stars
Neutron very dangerous and strange bodies. When giant star turns into a supernova, its core shrinks to the size of an earthly metropolis. The pressure inside the nucleus is so great that even the atoms inside begin to melt. When the atoms are so compressed that there is no space left between them, enormous energy accumulates and a powerful explosion occurs. After the explosion, an incredibly dense neutron star remains. A teaspoon of a Neutron Star will weigh 90 million tons.
A pulsar is the remains of a supernova explosion. A body that is similar to the mass and density of a neutron star. revolving with great speed, pulsars release radiation bursts into space from the northern and south poles. The rotation speed can reach 1000 revolutions per second.
When a star 30 times the size of our Sun explodes, it creates a star called Magnetar. Magnetars create powerful magnetic fields they are even stranger than neutron stars and pulsars. The magnetic field of Magnitar exceeds the earth's by several thousand times.
Black holes
After the death of hypernovae, stars even larger than a superstar, the most mysterious and dangerous place the universe is a black hole. After the death of such a star, the black hole begins to absorb its remains. The black hole has too much material to absorb and it throws the remains of the star back into space, forming 2 beams of gamma radiation.
As far as ours is concerned, the Sun certainly doesn't have enough mass to become a black hole, a pulsar, a magnetar, or even a neural star. By cosmic standards, our star is very small for such a finale of her life. Scientists say that after the depletion of fuel, our star will increase in size by several tens of times, which will allow it to absorb planets into itself. terrestrial group: Mercury, Venus, Earth and possibly Mars.
One of important achievements XX century was the understanding of the fact that almost all elements that are heavier than hydrogen and helium are formed in internal parts stars and enter the interstellar medium as a result of a supernova explosion - one of the most powerful phenomena in the universe.
Pictured: Brilliant stars and wisps of gas provide a breathtaking backdrop to the self-destruction of a massive star dubbed Supernova 1987A. Its explosion was observed by astronomers in southern hemisphere February 23, 1987. This Hubble image shows a supernova remnant surrounded by inner and outer rings of matter in diffuse clouds of gas. This three-color image is a composite of several photographs of the supernova and its neighboring region taken in September 1994, February 1996, and July 1997. Numerous bright blue stars near a supernova, these are massive stars, each of which is about 12 million years old and 6 times heavier than the Sun. They all belong to the same generation of stars as the one that exploded. The presence of bright gas clouds is another sign of the youth of this region, which is still fertile ground for the birth of new stars.
Initially, all stars whose brightness suddenly increased by more than 1,000 times were called novae. Flashing, such stars suddenly appeared in the sky, breaking the usual constellation configuration, and increased their brightness at the maximum, several thousand times, then their brightness began to drop sharply, and after a few years they became as weak as they were before the outbreak. The recurrence of flares, during each of which a star with high speed ejects up to one thousandth of its mass, is characteristic of new stars. And yet, for all the grandeur of the phenomenon of such a flash, it is not associated either with a radical change in the structure of the star, or with its destruction.
For five thousand years, information has been preserved about more than 200 bright outbursts of stars, if we restrict ourselves to those that did not exceed the brilliance of the 3rd magnitude. But when the extragalactic nature of the nebulae was established, it became clear that the novae flaring in them surpassed ordinary novae in their characteristics, since their luminosity often turned out to be equal luminosity throughout the galaxy in which they flared up. The unusual nature of such phenomena led astronomers to the idea that such events are something completely different from ordinary new stars, and therefore, in 1934, at the suggestion of the American astronomers Fritz Zwicky and Walter Baade, those stars whose flashes reach the luminosities of normal galaxies at their maximum brightness were identified into a separate, brightest in luminosity and rare class of supernovae.
In contrast to the outbursts of ordinary new stars, supernova outbursts in state of the art Our Galaxy is an extremely rare phenomenon, occurring no more than once every 100 years. The most striking outbreaks were in 1006 and 1054; information about them is contained in Chinese and Japanese treatises. In 1572, the outstanding astronomer Tycho Brahe observed the outbreak of such a star in the constellation of Cassiopeia, while Johannes Kepler was the last to follow the supernova in the constellation of Ophiuchus in 1604. For four centuries of the "telescopic" era in astronomy, no such flares were observed in our Galaxy. The position of the solar system in it is such that we can optically observe supernova explosions in about half of its volume, and in the rest of it the brightness of the flares is muted by interstellar absorption. IN AND. Krasovsky and I.S. Shklovsky calculated that supernova explosions in our galaxy occur on average once every 100 years. In other galaxies, these processes occur with approximately the same frequency; therefore, the main information about supernovae in the optical outburst stage was obtained from observations of them in other galaxies.
Realizing the importance of studying such powerful phenomena, astronomers W. Baade and F. Zwicky, who worked at the Palomar Observatory in the USA, began a systematic systematic search for supernovae in 1936. They had a Schmidt telescope at their disposal, which made it possible to photograph areas of several tens of square degrees and gave very clear images of even faint stars and galaxies. Over the course of three years, they discovered 12 supernova explosions in different galaxies, which were then studied using photometry and spectroscopy. As observational technology improved, the number of newly discovered supernovae steadily increased, and the subsequent introduction of automated search led to an avalanche-like increase in the number of discoveries (more than 100 supernovae per year at total— 1,500). AT last years on the large telescopes the search for very distant and weak supernovae was also launched, since their research can provide answers to many questions about the structure and fate of the entire universe. In one night of observations with such telescopes, more than 10 distant supernovae can be discovered.
As a result of the explosion of a star, which is observed as a supernova phenomenon, a nebula is formed around it, expanding at a tremendous speed (about 10,000 km / s). High expansion speed main feature, which distinguishes supernova remnants from other nebulae. In the remnants of supernovae, everything speaks of an explosion of enormous power, which scattered the outer layers of the star and imparted enormous speeds to individual pieces of the ejected shell.
crab nebula
No one space object did not give astronomers so much valuable information, as a relatively small Crab nebula, observed in the constellation Taurus and consisting of gaseous diffuse matter, expanding at high speed. This nebula, which is the remnant of a supernova observed in 1054, was the first galactic object with which a radio source was identified. It turned out that the nature of radio emission has nothing to do with thermal radiation: its intensity systematically increases with wavelength. Soon it was possible to explain the nature of this phenomenon. There must be a strong magnetic field in the supernova remnant that holds the cosmic rays(electrons, positrons, atomic nuclei) with speeds close to the speed of light. In a magnetic field they radiate electromagnetic energy narrow beam in the direction of travel. Detection of non-thermal radio emission from crab nebula prompted astronomers to search for supernova remnants precisely on this basis.
The nebula located in the constellation Cassiopeia turned out to be a particularly powerful source of radio emission - at meter wavelengths, the radio emission flux from it is 10 times higher than the flux from the Crab Nebula, although it is much further than the latter. In optical beams this rapidly expanding nebula is very weak. The nebula in Cassiopeia is believed to be the remnant of a supernova explosion that took place about 300 years ago.
A system of filamentous nebulae in the constellation Cygnus also showed radio emission characteristic of old supernova remnants. Radio astronomy has helped to find many other non-thermal radio sources that turned out to be supernova remnants. different ages. Thus, it was concluded that the remnants of supernovae, even tens of thousands of years ago, stand out among other nebulae with their powerful non-thermal radio emission.
As already mentioned, the Crab Nebula was the first object in which x-rays. In 1964, it was possible to discover that the source of X-ray radiation emanating from it is extended, although its angular dimensions are 5 times smaller than the angular dimensions of the Crab Nebula itself. From which it was concluded that X-rays are emitted not by a star that once erupted as a supernova, but by the nebula itself.
Supernova influence
On February 23, 1987, a supernova exploded in our neighboring galaxy, the Large Magellanic Cloud, which became extremely important for astronomers, since it was the first one that they, armed with modern astronomical instruments, could study in detail. And this star gave confirmation of a whole series of predictions. Simultaneously with the optical flash, special detectors installed in Japan and in the state of Ohio (USA) registered a stream of neutrinos - elementary particles that are born at very high temperatures during the collapse of the core of a star and easily penetrate through its shell. These observations confirmed the earlier assumption that about 10% of the mass of the collapsing stellar core is emitted as neutrinos at the moment when the core itself collapses into a neutron star. In very massive stars, during a supernova explosion, the cores are compressed to even greater densities and, probably, turn into black holes, but the outer layers of the star are still thrown off. In recent years, indications have appeared that some cosmic gamma-ray bursts are related to supernovae. It is possible that the nature of cosmic gamma-ray bursts is related to the nature of explosions.
Supernova explosions have a strong and diverse effect on the surrounding interstellar medium. The supernova shell, which is thrown off at a tremendous speed, scoops up and compresses the gas surrounding it, which can give impetus to the formation of new stars from the gas clouds. A team of astronomers led by Dr. John Hughes (Rutgers University), using observations from the Chandra Orbital X-ray Observatory (NASA), made important discovery, shedding light on how silicon, iron and other elements are formed in supernova explosions. X-ray image of the supernova remnant Cassiopeia A (Cas A) allows you to see clumps of silicon, sulfur and iron ejected during the explosion from interior areas stars.
The high quality, clarity and information content of the images of the Cas A supernova remnant obtained by the Chandra observatory allowed astronomers not only to determine chemical composition many nodes of this remnant, but also to find out exactly where these nodes were formed. For example, the most compact and bright nodes are composed mainly of silicon and sulfur with very little iron. This indicates that they formed deep inside the star, where temperatures reached three billion degrees during the collapse that ended in a supernova explosion. In other nodes, astronomers found a very high content of iron with impurities of a certain amount of silicon and sulfur. This substance was formed even deeper - in those parts where the temperature during the explosion reached higher values - from four to five billion degrees. Comparison of the arrangements in the supernova remnant Cas A of both bright silicon-rich and weaker iron-rich nodes revealed that the “iron” features originating from the most deep layers stars are located on the outer edges of the remnant. This means that the explosion threw the "iron" nodes farther than all the others. And even now, they seem to be moving away from the center of the explosion with more speed. The study of the data obtained by Chandra will make it possible to dwell on one of several mechanisms proposed by theorists that explain the nature of a supernova explosion, the dynamics of the process, and the origin of new elements.
SN I supernovae have very similar spectra (with no hydrogen lines) and light curve shapes, while SN II spectra contain bright hydrogen lines and are distinguished by a variety of both spectra and light curves. In this form, the classification of supernovae existed until the mid-1980s. And with the start wide application With CCD receivers, the quantity and quality of observational material has increased significantly, which made it possible to obtain spectrograms for previously inaccessible faint objects, to determine the intensity and width of lines with much greater accuracy, and to record fainter lines in the spectra. As a result, the apparently established binary classification of supernovae began to rapidly change and become more complex.
Supernovae are also distinguished by the types of galaxies in which they flare up. In spiral galaxies, supernovae of both types flare up, but in elliptical galaxies, where there is almost no interstellar medium and the process of star formation has ended, only supernovae of type SN I are observed, obviously, before the explosion - these are very old stars, the masses of which are close to the sun. And since the spectra and light curves of supernovae of this type are very similar, it means that the same stars explode in spiral galaxies. natural end evolutionary path stars with masses close to the sun - the transformation into a white dwarf with the simultaneous formation planetary nebula. There is almost no hydrogen in the composition of a white dwarf, since it is the end product of the evolution of a normal star.
Several planetary nebulae are formed annually in our Galaxy, therefore, most of the stars of this mass quietly complete their life path, and only once every hundred years does an SN I type supernova burst. What reasons determine a very special ending, not similar to the fate of other stars of the same kind? The famous Indian astrophysicist S. Chandrasekhar showed that in the event that a white dwarf has a mass less than about 1.4 solar masses, it will calmly "live out" its life. But if it is in a close enough binary system, its powerful gravity is able to "pull" matter from the companion star, which leads to a gradual increase in mass, and when it passes allowable limit- going on powerful explosion leading to the death of the star.
Supernovae SN II are clearly associated with young ones, massive stars, in the shells of which hydrogen is present in large quantities. Explosions of this type of supernovae are considered the final stage in the evolution of stars with an initial mass of more than 8-10 solar masses. In general, the evolution of such stars proceeds quite quickly - in a few million years they burn their hydrogen, then helium, which turns into carbon, and then carbon atoms begin to transform into atoms with higher atomic numbers.
In nature, the transformations of elements with a large release of energy end in iron, the nuclei of which are the most stable, and no energy is released during their fusion. Thus, when the core of a star becomes iron, the release of energy in it stops, to resist gravitational forces it can no longer, and therefore begins to rapidly shrink, or collapse.
The processes occurring during the collapse are still far from full understanding. However, it is known that if all the matter of the core turns into neutrons, then it can resist the forces of attraction - the core of the star turns into a "neutron star", and the collapse stops. At the same time, it highlights great energy, which enters the shell of the star and causes expansion, which we see as a supernova explosion.
This was to be expected genetic connection between supernova explosions and the formation neutron stars and black holes. If the evolution of the star before this happened “quietly”, then its shell should have a radius hundreds of times greater than the radius of the Sun, and also retain enough hydrogen to explain the spectrum of SN II supernovae.
Supernovae and pulsars
The fact that after a supernova explosion, in addition to the expanding shell and various types radiation remains and other objects, it became known in 1968 due to the fact that a year earlier, radio astronomers discovered pulsars - radio sources, the radiation of which is concentrated in separate pulses, repeating through strictly certain interval time. Scientists were struck by the strict periodicity of the pulses and the shortness of their periods. The greatest attention was drawn to the pulsar, the coordinates of which were close to the coordinates of a very interesting nebula for astronomers, located in southern constellation Sails, which is believed to be the remnant of a supernova explosion - its period was only 0.089 seconds. And after the discovery of a pulsar in the center of the Crab Nebula (its period was 1/30 of a second), it became clear that pulsars are somehow connected with supernova explosions. In January 1969, a pulsar from the Crab Nebula was identified with a faint 16th-magnitude star that changes its brightness with the same period, and in 1977, a pulsar in the constellation of Sails was also identified with a star.
The periodicity of the emission of pulsars is associated with their rapid rotation, but none ordinary star, even a white dwarf, could not rotate with a period characteristic of pulsars - it would be immediately torn apart centrifugal forces, and only a neutron star, very dense and compact, could resist them. As a result of the analysis of many options, scientists came to the conclusion that supernova explosions are accompanied by the formation of neutron stars - a qualitatively new type of objects, the existence of which was predicted by the theory of evolution of stars of large mass.
Supernovae and black holes
The first proof of a direct connection between a supernova explosion and the formation of a black hole was obtained by Spanish astronomers. As a result of studying the radiation emitted by a star orbiting a black hole in the Nova Scorpii 1994 binary system, it was found that it contains a large number of oxygen, magnesium, silicon and sulfur. There is an assumption that these elements were captured by it when a nearby star, having survived a supernova explosion, turned into a black hole.
Supernovae (particularly Type Ia supernovae) are among the brightest stellar objects in the universe, so even the most distant ones can be explored with currently available equipment. Many Type Ia supernovae have been discovered in relatively nearby galaxies. Sufficiently accurate estimates of the distances to these galaxies made it possible to determine the luminosity of supernovae that burst out in them. If we assume that distant supernovae have the same average luminosity, then according to the observed magnitude at maximum brightness, one can also estimate the distance to them. Comparison of the distance to a supernova with the removal rate (redshift) of the galaxy in which it exploded makes it possible to determine the main quantity characterizing the expansion of the Universe - the so-called Hubble constant.
Even 10 years ago, values for it were obtained that differed by almost two times - from 55 to 100 km/s Mpc, today the accuracy has been significantly increased, as a result of which a value of 72 km/s Mpc is accepted (with an error of about 10%) . For distant supernovae, the redshift of which is close to 1, the relationship between the distance and the redshift also makes it possible to determine quantities that depend on the density of matter in the Universe. According to general theory Einstein's relativity, it is the density of matter that determines the curvature of space, and, consequently, further fate Universe. Namely: will it expand indefinitely or will this process ever stop and be replaced by contraction. Latest Research supernovae have shown that most likely the density of matter in the universe is insufficient to stop the expansion, and it will continue. And in order to confirm this conclusion, new observations of supernovae are needed.
right after the explosion depends a lot on luck. It is she who determines whether it will be possible to study the processes of the birth of a supernova, or whether one will have to guess about them in the wake of an explosion - propagating from former star planetary nebula. The number of telescopes built by man is not large enough to constantly observe the entire sky, especially in all regions of the spectrum. electromagnetic radiation. Often, amateur astronomers come to the aid of scientists, directing their telescopes wherever they please, and not at interesting and important objects for study. But a supernova explosion can happen anywhere!
An example of help from amateur astronomers is a supernova in the spiral galaxy M51. Known as the Pinwheel Galaxy, it is very popular among lovers of observing the Universe. The galaxy is located at a distance of 25 million light-years from us and is turned directly towards us with its plane, due to which it is very convenient to observe it. The galaxy has a satellite that is in contact with one of the arms of M51. Light from a star that exploded in the galaxy reached Earth in March 2011 and was recorded by amateur astronomers. The supernova soon received the official designation 2011dh and became the focus of both professional and amateur astronomers. “M51 is one of the closest galaxies to us, it is extremely beautiful and therefore widely known,” says Caltech employee Sheeler van Dyck.
The supernova 2011dh considered in detail turned out to belong to a rare type IIb class of explosions. Such explosions occur when a massive star is stripped of virtually all of its outer garb of hydrogen fuel, which is likely to be pulled over by its binary companion. After that, due to lack of fuel, stops thermonuclear fusion, the star's radiation cannot resist gravity, which tends to compress the star, and it falls towards the center. This is one of the two ways of supernova explosions, and in such a scenario (a star falling on itself under the influence of gravity), only every tenth star gives rise to a type IIb explosion.
There are several well-founded hypotheses regarding general scheme the birth of a type IIb supernova, but reconstructing the exact chain of events is very difficult. Since a star cannot be said to go supernova very soon, it is impossible to prepare for its careful observation. Of course, studying the state of a star may suggest that it will soon become a supernova, but this is on the time scale of the Universe in millions of years, while observation requires knowing the time of the explosion with an accuracy of several years. Only occasionally do astronomers get lucky and have detailed pictures of the star before the explosion. In the case of the M51 galaxy, this situation takes place - due to the popularity of the galaxy, there are many images of it in which 2011dh has not yet exploded. “Within days of the discovery of the supernova, we turned to the archives orbiting telescope Hubble. As it turned out, with the help of this telescope, a detailed mosaic of the M51 galaxy was previously created in different lengths waves,” says van Dyck. In 2005, when the Hubble telescope photographed the 2011dh region, there was only an inconspicuous yellow giant star in its place.
Observations of supernova 2011dh have shown that it does not fit well with the standard idea of an explosion of a huge star. On the contrary, it is more suitable as the result of the explosion of a small star, for example, the yellow supergiant companion from Hubble images, which has lost almost all of its atmosphere. Under the influence of the gravity of a nearby giant, only its core remained from the star, which exploded. “We decided that the precursor to the supernova was an almost completely stripped star, blue and therefore invisible to Hubble,” says van Dyck. - The yellow giant hid its small blue companion with its radiation until it exploded. That is our conclusion."
Another team of researchers studying the star 2011dh came to the opposite conclusion, which coincides with the classical theory. It was the yellow giant that was the precursor of the supernova, according to Justin Mound, an employee of the Queen's University in Belfast. However, in March of this year, a supernova revealed a mystery to both teams. The problem was first noticed by van Dyck, who decided to collect additional information about 2011dh using the Hubble telescope. However, the device did not find a large yellow star. "We just wanted to watch the evolution of a supernova again," says van Dyck. “We could never have imagined that the yellow star would go somewhere.” Another team came to the same conclusions using ground telescopes: The giant has disappeared.
The disappearance of the yellow giant points to it as the true supernova precursor. Van Dyk's post resolves this controversy: "The other team was completely right, we were wrong." However, the study of supernova 2011dh does not end there. As the brightness of 2011dh fades, M51 will return to its pre-explosion state (albeit without one bright star). By the end of this year, the brightness of the supernova should drop enough to show the companion of the yellow supergiant - if it was, as suggested classical theory the birth of type IIb supernovae. Several groups of astronomers have already reserved Hubble observation time to study the evolution of 2011dh. "We need to find a binary companion for the supernova," says van Dyck. “If it is discovered, there will be a confident understanding of the origin of such explosions.”
