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In 1967, scientists accidentally discovered a fast periodic pulse signal, and at the beginning they guessed it was an alien signal, then the neutron star and then quark stars. The road of exploration is tortuous, and scientists are trying to blot out fog and search for the truth. Taking fast pace, and to encounter all kinds of pulsars in the space with us now!
Pulsar：from Alien Signal, Quarrcsrarto rhe Neurron Star
In the year of 1967, a doctoral student of Cambridge University, Joslyn Bell had intended to use a newly built radio telescope to study quasars by flashing objects (similar to the stars blink phenomenon), but inadvertently found a kind of fast periodic pulse signal. At first, she and mentor, Professor Hughes, did not know what it was, even once they doubted if it was a signal by alien, but soon, they confirmed that it was a celestial body that had been discovered, so it was named pulsar. In 1968, people finally understood celestial pulsars should be what the Soviet physicist Landau predicted in 1932 as neutron configuration a neutron star. Pulsar pulse period is the rotation period. Beam was emitted from the two poles of the field of neutron of rapid rotation, and if the beam can sweep the planet, we can receive periodic“flash,”asif the twinkling“lighthouse”in the universe.
Where do those neutron stars come from? According to stellar evolution theory, which is the predecessor of the larger mass stars; at the end of its“life”through a violent supernova explosion, the stars blew out most of the periphery of the material to form brilliant supernova remnants. The core material was compressed into high-density objects under a strong gravitational pull. If the core area of the material is less than 3 times the mass of the sun, they were squeezed into the ball of about 10 km by gravity, and thus forming the neutron star. Neutron star exceeds its father stars in terms of gravitational field, the magnetic field and electric field strength, and the density of matter, so it can be regarded as the ultra high energy strong gravitational physics laboratory in the universe.
As mentioned above, at the beginning of the discovery of pulsars, it is believed that the pulsar is a neutron star. However, 40 years of theoretical study showed that the pulsar might be the“twin brother” of the neutron star-- quark stars. To understand this, we’d better look back history.
The concept of the neutron star came from a bold conjecture. After the neutron was discovered in 1932, Landau would guess this uncharged elementary particles could stick together by the nuclear force, and formed a so-called neutron stars. Soon, the neutron star can be proved theoretically stable, in the following 30 years, the research of the stellar theory revealed that the neutron star was one of the ultimate product of stellar evolution. But after the 1950s, people changed their views on“neutron is one of the most basic particle”, some of the experiments showed that it might be made up of smaller elementary particles as the proton. In 1964, American physicist Gell-Mann and Zweig independently proposed that neutrons and protons are made up of quarks. Four years later, this particle was really discovered in a particle accelerator at Stanford University, was discovered. Soon, in 1969, Soviet physicist lvanenko and Kurdgelaidze conjured up that the core of neutron stars may be caused by quarks, instead of neutron component; thereafter, the concept of the quark star-entirely composed of quarks Stars emerged, became the new adventure park of theorists. Discovery of a particle spawned the conjecture of the object constituted by the particle, so we can say that history sometimes is so similar. Theoretically, neutron stars and quark stars can be born in a supernova, and they can produce very similar phenomenon for example, radio pulses and etc., then, how to prove that pulsars are neutron stars or the quark star, or whether quark stars really exist, hasbecome one of the most challenging the problems in the research field of pulsar. Although the physical properties of quark stars and neutron stars differ, observational evidence had not been found yet. If FAST could find quark stars, it will be a remarkable discovery that can provide important experimental evidence for strong interactions and quark mass physical properties of elementary particles.
Pulsar of All Kinds
Up to now, more than 2500 pulsars had been found. A prominent feature of pulsar is the fast speed of rotation, and its slowest turn takes ten seconds, while to the fastest extent it turns 716 laps per second, nearly twice faster than the maximum speed of Fl racing engines. If asked the strongest magnetic objects in the universe, the answer must be pulsar because the magnetic field of their stellar surface can reach several thousand to hundreds of billions Tesla which is more than all the known objects. Many people have no concept of the field unit--Tesla; for example, the magnet surface magnetic field of small goods in daily life is generally about l Tesla, how strong the magnetic field of the pulsar is.
Astronomically, various celestial bodies are often regarded as certain zoos, such as Galaxy Zoo, pulsars Zoo. After 40 years of observation, there are nearly 10 varieties of pulsar zoos. Here let’s take a look at some of the most useful or the most peculiar pulsars.
Millisecond Pulsar: The Most Accurate Clock
In accordance with the difference between the rotation periods, the pulsar is usually divided into normal pulsars and millisecond pulsars. The former rotation period is longer than tens of milliseconds and its magnetic field is strong while the latter’s rotation period is shorter than several tens of milliseconds and its magnetic field is weak and very old. 80% of more than 200 known millisecond pulsars are in the binary system. Generally believed that millisecond pulsar in the binary system is formed by the process that normal millisecond pulsar swallows the gas of companion stars and the acceleration of rotation.
Most of the pulsar’s rotations are becoming slowly, and they obey certain rules on the whole. However, through long-term monitoring, it was found that there are all kinds of irregular behaviors in most of the pulsar’s rotation slow-down, so it is difficult to make highly accurate predictions. Only a few millisecond pulsars are very stable, of which some are more accurate atomic hydrogen than those on the ground. Nature provides such a precise clock, so it’s nature for astronomers to make full use of its role. For example, they can be used to develop independent pulsar time standard for checking the daily timing system based on the atomic clock; can be used to measure the mass of the solar system planets; also can be used to capture gravitational waves, and so on. Magnetic Stars:could be the celestial body boast strongest magnetic field in the umverse
It is the general name of those special celestial bodies detected by X-ray and gamma ray satellite in the 1970s, which initially was not called a magnetic star, but two daunting names to ordinary people anomalous X-ray pulsar and SGRs. They have a very attractive characteristic for astronomers that the radiation power of their X-ray or gamma far exceeds the kinetic energy provided by the chage of star’s rotation. It sounds like a modest-income person leads an extravagant life. Where does the extra energy come from? It has always been a mystery.
In 1992, American astronomer Duncan and Thompson conjectured that these extra energy come from the energy release of enormous magnetic fields. This requires the surface magnetic fields of stars exceed 4.4 billion stellar which is much stronger than ordinary pulsars, so they named the celestial body as“magnetic star”. For theorists, the magnetic star is difficult to resist because the material behavior of powerful magnetic field is like gold mine that is less dug by in the past and there can be no ground experimental conditions. Magnetic stars provide excellent research opportunities. But dissenting voices still exist, some people think that the energy emerged because the neutron star devours its surrounding gas, and the neutron star itself do not have powerful magnetic field. Institutions like NASA also pay high attention to the discovery of magnetic stars, so the public is getting familiar with magnetic stars. So far, there are 28 magnetic stars have been found, and if they are confirmed with powerful magnetic fields in the future, they are sure to be the objects with the strongest magnetic field in the universe.
Null Pulsar: Sporadic Radiation
Most pulsars emit radio pulses consistently, but some are sporadic. The one with large number is called null star, and now about 200 null stars have been found. The radiation of this pulsar star usually will continue for some time, and then keep silence for a period of time from a few seconds to several minutes, which is known as the zero pulse phenomenon. The proportion of most of the null pulsars remaining quiet is hard to exceed 20%, and only few of them can reach 90%. In 2006, an extreme variety was discovered and known as RRATs which is an abbreviation and has similar pronunciation with mouse in English. Each time they issue a pulse signal lasts only a few milliseconds, and then there is a long period of silence from few minutes to a few hours, and after that they then send the next one. Another extreme variety is called intermittent pulsars which enjoy much longer silence. For example, a pulsar named PSRB1937 + 21 usually“work”5 t0 10 days (with radiation) and then“rest”for 4 t0 5 weeks (no radiation). Some pulsars even“rest”longer.
Pulsars may be small, but they have great energy, rich phenomenon and a lot of variety. What’s particularly important is the study of pulsars are likely to help scientists Shape a deep understanding of the basic laws of the microscopic world and macroscopic world. in the past 40 years, the discovery of pulsars (1974) and the binary pulsar gravitational wave theory of indirect verification (1993) were awarded the Nobel Prize in Physics respectively. The future reseaarch for the pulsar may still have an important discovery that worth a Nobel prize.
Pulsar：from Alien Signal, Quarrcsrarto rhe Neurron Star
In the year of 1967, a doctoral student of Cambridge University, Joslyn Bell had intended to use a newly built radio telescope to study quasars by flashing objects (similar to the stars blink phenomenon), but inadvertently found a kind of fast periodic pulse signal. At first, she and mentor, Professor Hughes, did not know what it was, even once they doubted if it was a signal by alien, but soon, they confirmed that it was a celestial body that had been discovered, so it was named pulsar. In 1968, people finally understood celestial pulsars should be what the Soviet physicist Landau predicted in 1932 as neutron configuration a neutron star. Pulsar pulse period is the rotation period. Beam was emitted from the two poles of the field of neutron of rapid rotation, and if the beam can sweep the planet, we can receive periodic“flash,”asif the twinkling“lighthouse”in the universe.
Where do those neutron stars come from? According to stellar evolution theory, which is the predecessor of the larger mass stars; at the end of its“life”through a violent supernova explosion, the stars blew out most of the periphery of the material to form brilliant supernova remnants. The core material was compressed into high-density objects under a strong gravitational pull. If the core area of the material is less than 3 times the mass of the sun, they were squeezed into the ball of about 10 km by gravity, and thus forming the neutron star. Neutron star exceeds its father stars in terms of gravitational field, the magnetic field and electric field strength, and the density of matter, so it can be regarded as the ultra high energy strong gravitational physics laboratory in the universe.
As mentioned above, at the beginning of the discovery of pulsars, it is believed that the pulsar is a neutron star. However, 40 years of theoretical study showed that the pulsar might be the“twin brother” of the neutron star-- quark stars. To understand this, we’d better look back history.
The concept of the neutron star came from a bold conjecture. After the neutron was discovered in 1932, Landau would guess this uncharged elementary particles could stick together by the nuclear force, and formed a so-called neutron stars. Soon, the neutron star can be proved theoretically stable, in the following 30 years, the research of the stellar theory revealed that the neutron star was one of the ultimate product of stellar evolution. But after the 1950s, people changed their views on“neutron is one of the most basic particle”, some of the experiments showed that it might be made up of smaller elementary particles as the proton. In 1964, American physicist Gell-Mann and Zweig independently proposed that neutrons and protons are made up of quarks. Four years later, this particle was really discovered in a particle accelerator at Stanford University, was discovered. Soon, in 1969, Soviet physicist lvanenko and Kurdgelaidze conjured up that the core of neutron stars may be caused by quarks, instead of neutron component; thereafter, the concept of the quark star-entirely composed of quarks Stars emerged, became the new adventure park of theorists. Discovery of a particle spawned the conjecture of the object constituted by the particle, so we can say that history sometimes is so similar. Theoretically, neutron stars and quark stars can be born in a supernova, and they can produce very similar phenomenon for example, radio pulses and etc., then, how to prove that pulsars are neutron stars or the quark star, or whether quark stars really exist, hasbecome one of the most challenging the problems in the research field of pulsar. Although the physical properties of quark stars and neutron stars differ, observational evidence had not been found yet. If FAST could find quark stars, it will be a remarkable discovery that can provide important experimental evidence for strong interactions and quark mass physical properties of elementary particles.
Pulsar of All Kinds
Up to now, more than 2500 pulsars had been found. A prominent feature of pulsar is the fast speed of rotation, and its slowest turn takes ten seconds, while to the fastest extent it turns 716 laps per second, nearly twice faster than the maximum speed of Fl racing engines. If asked the strongest magnetic objects in the universe, the answer must be pulsar because the magnetic field of their stellar surface can reach several thousand to hundreds of billions Tesla which is more than all the known objects. Many people have no concept of the field unit--Tesla; for example, the magnet surface magnetic field of small goods in daily life is generally about l Tesla, how strong the magnetic field of the pulsar is.
Astronomically, various celestial bodies are often regarded as certain zoos, such as Galaxy Zoo, pulsars Zoo. After 40 years of observation, there are nearly 10 varieties of pulsar zoos. Here let’s take a look at some of the most useful or the most peculiar pulsars.
Millisecond Pulsar: The Most Accurate Clock
In accordance with the difference between the rotation periods, the pulsar is usually divided into normal pulsars and millisecond pulsars. The former rotation period is longer than tens of milliseconds and its magnetic field is strong while the latter’s rotation period is shorter than several tens of milliseconds and its magnetic field is weak and very old. 80% of more than 200 known millisecond pulsars are in the binary system. Generally believed that millisecond pulsar in the binary system is formed by the process that normal millisecond pulsar swallows the gas of companion stars and the acceleration of rotation.
Most of the pulsar’s rotations are becoming slowly, and they obey certain rules on the whole. However, through long-term monitoring, it was found that there are all kinds of irregular behaviors in most of the pulsar’s rotation slow-down, so it is difficult to make highly accurate predictions. Only a few millisecond pulsars are very stable, of which some are more accurate atomic hydrogen than those on the ground. Nature provides such a precise clock, so it’s nature for astronomers to make full use of its role. For example, they can be used to develop independent pulsar time standard for checking the daily timing system based on the atomic clock; can be used to measure the mass of the solar system planets; also can be used to capture gravitational waves, and so on. Magnetic Stars:could be the celestial body boast strongest magnetic field in the umverse
It is the general name of those special celestial bodies detected by X-ray and gamma ray satellite in the 1970s, which initially was not called a magnetic star, but two daunting names to ordinary people anomalous X-ray pulsar and SGRs. They have a very attractive characteristic for astronomers that the radiation power of their X-ray or gamma far exceeds the kinetic energy provided by the chage of star’s rotation. It sounds like a modest-income person leads an extravagant life. Where does the extra energy come from? It has always been a mystery.
In 1992, American astronomer Duncan and Thompson conjectured that these extra energy come from the energy release of enormous magnetic fields. This requires the surface magnetic fields of stars exceed 4.4 billion stellar which is much stronger than ordinary pulsars, so they named the celestial body as“magnetic star”. For theorists, the magnetic star is difficult to resist because the material behavior of powerful magnetic field is like gold mine that is less dug by in the past and there can be no ground experimental conditions. Magnetic stars provide excellent research opportunities. But dissenting voices still exist, some people think that the energy emerged because the neutron star devours its surrounding gas, and the neutron star itself do not have powerful magnetic field. Institutions like NASA also pay high attention to the discovery of magnetic stars, so the public is getting familiar with magnetic stars. So far, there are 28 magnetic stars have been found, and if they are confirmed with powerful magnetic fields in the future, they are sure to be the objects with the strongest magnetic field in the universe.
Null Pulsar: Sporadic Radiation
Most pulsars emit radio pulses consistently, but some are sporadic. The one with large number is called null star, and now about 200 null stars have been found. The radiation of this pulsar star usually will continue for some time, and then keep silence for a period of time from a few seconds to several minutes, which is known as the zero pulse phenomenon. The proportion of most of the null pulsars remaining quiet is hard to exceed 20%, and only few of them can reach 90%. In 2006, an extreme variety was discovered and known as RRATs which is an abbreviation and has similar pronunciation with mouse in English. Each time they issue a pulse signal lasts only a few milliseconds, and then there is a long period of silence from few minutes to a few hours, and after that they then send the next one. Another extreme variety is called intermittent pulsars which enjoy much longer silence. For example, a pulsar named PSRB1937 + 21 usually“work”5 t0 10 days (with radiation) and then“rest”for 4 t0 5 weeks (no radiation). Some pulsars even“rest”longer.
Pulsars may be small, but they have great energy, rich phenomenon and a lot of variety. What’s particularly important is the study of pulsars are likely to help scientists Shape a deep understanding of the basic laws of the microscopic world and macroscopic world. in the past 40 years, the discovery of pulsars (1974) and the binary pulsar gravitational wave theory of indirect verification (1993) were awarded the Nobel Prize in Physics respectively. The future reseaarch for the pulsar may still have an important discovery that worth a Nobel prize.