This is a presentation on the use of spectroscopy in astronomy, especially in discovering celestial bodies. Small presentation with minimum technical details.
This document discusses the use of spectroscopy in astronomical observations. Spectroscopy can be used to derive many properties of distant stars and galaxies, such as chemical composition, temperature, density, mass, distance, luminosity, and relative motion. However, Earth's atmosphere interferes with certain wavelengths of light. Infrared and ultraviolet light are absorbed, requiring the use of satellites. Spectroscopy has also been used to discover compounds in exoplanet atmospheres like water vapor and methane. Future advancements may allow astronomers to better study objects and find habitable planets.
Binary stars are two stars orbiting a common center of mass, with the brighter star classified as the primary and dimmer as the secondary. Galileo first observed binary stars in 1617 when he noticed one star seemed to be two. Binary stars can form when a massive star captures a passing star. There are four main classifications of binary stars: visual binaries which can be seen separately through a telescope; spectroscopic binaries which appear close but can't be resolved; eclipsing binaries whose orbits cause one star to pass in front of the other; and astrometric binaries where the companion star can only be inferred.
This document discusses how the spectral classification of stars can reveal information about their composition and temperature. It explains that stars are classified into seven main categories (O, B, A, F, G, K, M) based on their absorption spectra, with O being the hottest and M being the coolest. Each class is associated with a range of surface temperatures and colors. By analyzing a star's spectrum, astronomers can determine what chemical elements are present in its atmosphere and measure its temperature, allowing insights into its composition and properties.
Stars are large balls of ionized gas held together by gravity that emit energy through nuclear reactions. They are classified based on size, temperature, and brightness. Size categories include super giants, red giants, main sequence, white dwarfs, and neutron stars. Temperature determines color, from red (coolest) to blue (hottest). Brightness depends on both a star's intrinsic luminosity and its distance from Earth. Spectrographs are used to analyze starlight and determine properties like chemical composition, temperature, and distance.
The Milky Way Galaxy is a spiral galaxy that contains the solar system and Earth. It is estimated to be 100,000 light years in diameter and contains millions to billions of stars. The galaxy is composed of a disk, halo, and central bulge. Spiral arms in the disk contain dense clouds of gas and dust where new stars are forming. The sun orbits near the edge of the disk at a distance of about 8.2 kiloparsecs from the galactic center. All elements heavier than hydrogen and helium were produced through nuclear fusion in earlier generations of stars within the Milky Way over billions of years.
This document provides an overview of the characteristics, classifications, motions, and significance of stars. It discusses their sizes, colors, temperatures, compositions, and magnitudes. Stars are classified based on their spectral types, which relate to their surface temperatures. The Hertzsprung-Russell diagram plots stars' luminosities and temperatures. Stars exhibit both apparent and actual motions, including proper motion across the sky. Studying stars helps us understand how elements are formed, how our solar system evolved, and the dynamics influencing galaxies.
The document discusses astronomy and the scientific study of celestial objects. It provides information on stars, galaxies, and the formation and components of the solar system. Specifically, it notes that astronomy is the study of matter in outer space, including the positions, dimensions, distribution, motion, composition, energy, and evolution of celestial bodies. It also summarizes that the universe started as a single point which exploded outward in the big bang and has been expanding ever since. Finally, it outlines the key parts of the solar system, including the sun, planets, asteroids, comets, and meteoroids.
This document discusses the use of spectroscopy in astronomical observations. Spectroscopy can be used to derive many properties of distant stars and galaxies, such as chemical composition, temperature, density, mass, distance, luminosity, and relative motion. However, Earth's atmosphere interferes with certain wavelengths of light. Infrared and ultraviolet light are absorbed, requiring the use of satellites. Spectroscopy has also been used to discover compounds in exoplanet atmospheres like water vapor and methane. Future advancements may allow astronomers to better study objects and find habitable planets.
Binary stars are two stars orbiting a common center of mass, with the brighter star classified as the primary and dimmer as the secondary. Galileo first observed binary stars in 1617 when he noticed one star seemed to be two. Binary stars can form when a massive star captures a passing star. There are four main classifications of binary stars: visual binaries which can be seen separately through a telescope; spectroscopic binaries which appear close but can't be resolved; eclipsing binaries whose orbits cause one star to pass in front of the other; and astrometric binaries where the companion star can only be inferred.
This document discusses how the spectral classification of stars can reveal information about their composition and temperature. It explains that stars are classified into seven main categories (O, B, A, F, G, K, M) based on their absorption spectra, with O being the hottest and M being the coolest. Each class is associated with a range of surface temperatures and colors. By analyzing a star's spectrum, astronomers can determine what chemical elements are present in its atmosphere and measure its temperature, allowing insights into its composition and properties.
Stars are large balls of ionized gas held together by gravity that emit energy through nuclear reactions. They are classified based on size, temperature, and brightness. Size categories include super giants, red giants, main sequence, white dwarfs, and neutron stars. Temperature determines color, from red (coolest) to blue (hottest). Brightness depends on both a star's intrinsic luminosity and its distance from Earth. Spectrographs are used to analyze starlight and determine properties like chemical composition, temperature, and distance.
The Milky Way Galaxy is a spiral galaxy that contains the solar system and Earth. It is estimated to be 100,000 light years in diameter and contains millions to billions of stars. The galaxy is composed of a disk, halo, and central bulge. Spiral arms in the disk contain dense clouds of gas and dust where new stars are forming. The sun orbits near the edge of the disk at a distance of about 8.2 kiloparsecs from the galactic center. All elements heavier than hydrogen and helium were produced through nuclear fusion in earlier generations of stars within the Milky Way over billions of years.
This document provides an overview of the characteristics, classifications, motions, and significance of stars. It discusses their sizes, colors, temperatures, compositions, and magnitudes. Stars are classified based on their spectral types, which relate to their surface temperatures. The Hertzsprung-Russell diagram plots stars' luminosities and temperatures. Stars exhibit both apparent and actual motions, including proper motion across the sky. Studying stars helps us understand how elements are formed, how our solar system evolved, and the dynamics influencing galaxies.
The document discusses astronomy and the scientific study of celestial objects. It provides information on stars, galaxies, and the formation and components of the solar system. Specifically, it notes that astronomy is the study of matter in outer space, including the positions, dimensions, distribution, motion, composition, energy, and evolution of celestial bodies. It also summarizes that the universe started as a single point which exploded outward in the big bang and has been expanding ever since. Finally, it outlines the key parts of the solar system, including the sun, planets, asteroids, comets, and meteoroids.
1. The document describes the motions of objects in the sky and our location in the universe, including a description of the Milky Way galaxy and our solar system.
2. Key concepts covered include the coordinate systems used to locate celestial objects, precession of the Earth, and the causes of the seasons due to the tilt of the Earth's axis.
3. Motions of objects like the sun and stars are explained, including how the sun appears to move along the ecliptic and causes the seasons as the Earth orbits around it.
A supernova is a massive stellar explosion that occurs at the end of a large star's life. There are two main types of supernovae that can form - Type I occurs when a white dwarf star accumulates too much matter from a nearby star, and Type II occurs when a massive star runs out of nuclear fuel and collapses under its own gravity. During its explosion, a supernova can outshine its entire host galaxy and radiate more energy than our Sun will over its entire lifetime, making them the primary source of heavy elements in the universe.
The document discusses the four fundamental forces: gravitational, electromagnetic, nuclear, and weak. It summarizes that the nuclear force was discovered after neutrons were discovered in 1932, and holds nucleons together in the nucleus. The nuclear force is charge independent, very strong but short range, repulsive at short distances, and acts through the exchange of pions between nucleons. The document provides details on the Yukawa potential and uncertainty principle as they relate to the nuclear force. It poses a multiple choice question about identifying an incorrect statement regarding the nuclear force.
The Sun formed around 5 billion years ago from a cloud of gas and dust. Through the process of nuclear fusion at its core, the Sun generates immense heat and light by converting hydrogen into helium. It is a common yellow star that is part of a cycle that creates convection currents within its surface and sunspots that follow an 11-year cycle. The Sun provides the energy necessary to sustain life on Earth but will eventually exhaust its hydrogen fuel in around 5 billion years.
1) A matéria negra compõe cerca de 23% da densidade de energia do universo e interage apenas gravitacionalmente.
2) O destino final do universo depende da quantidade total de matéria, sendo possível um Big Rip ou Big Crunch.
3) Experimentos no CERN sugeriram que neutrinos viajaram mais rápido que a luz, o que desafiaria a teoria da relatividade, embora possa ser explicado por dimensões extras.
Interference occurs when two waves superimpose to form a resultant wave of greater or lower amplitude. There are two main types of interference: constructive and destructive. Constructive interference occurs when wave crests or troughs overlap, increasing amplitude, while destructive interference occurs when a crest and trough overlap, decreasing amplitude. Thin film interference is studied using thin films that reflect light, which can interfere and be analyzed to determine properties like film thickness. Interferometers exploit the interference of light to make extremely precise measurements of distance and other values.
IB Astrophysics - stellar radiation and types - Flippingphysics by nothingnerdyNothingnerdy
This document discusses stellar radiation and stellar classification. Stars are classified based on their temperature, which is determined from their blackbody spectrum. Hotter stars have shorter peak wavelengths and are classified as O, B, A types while cooler stars like K and M types have longer peak wavelengths. A star's luminosity and temperature are correlated on the Hertzsprung-Russell diagram, with the main sequence containing the bulk of stars.
This document provides an introduction to particle physics, including:
- A brief history of discoveries of the elementary constituents of matter like protons, neutrons, electrons.
- An overview of the four fundamental forces and how they control particle behavior.
- Explanations of conservation laws, neutrino theory, and early experiments verifying mass-energy equivalence.
- Descriptions of the Standard Model of particle families, forces, the quark model, and antimatter discoveries.
This document provides a summary of stellar evolution from the birth of stars to their death. It discusses how stars are formed inside nebulae from collapsing gas clouds. As stars age, they progress through different stages such as protostars, T-Tauri stars, and red giants. More massive stars may die in supernova explosions, leaving behind neutron stars or black holes. Lower mass stars end as white dwarfs. The document also describes different types of nebulae and compact objects like neutron stars and black holes.
Planetary nebulae form during the late stages of evolution for low-to-medium mass stars. As a star expands into a red giant, it ejects its outer layers through pulsations and stellar winds. The hot core ionizes the ejected gas, causing it to glow brightly. This energized shell of nebulous gas appears as a planetary nebula. Examples are the Helix Nebula and Ring Nebula. More massive stars may explode as supernovae, leaving behind neutron stars or black holes, depending on the star's original mass. The document discusses these stages of stellar evolution and death that give rise to different astronomical phenomena like planetary nebulae and neutron stars.
This document provides an overview of elementary particles. It discusses their classification into baryons, leptons, and mesons. Baryons include protons, neutrons, and heavier hyperons. Leptons contain electrons, photons, neutrinos, and muons. Mesons have masses between baryons and leptons. Each particle is described along with its properties. The document also discusses particles and their antiparticles, and conservation laws related to parity, charge conjugation, time reversal, and the combined CPT symmetry.
The splitting of the main spectral line into two or more components with a slight variation in wavelength in the magnetic field is called fine structure in spectroscopy. It means that, in the magnetic field, the electron energy splits to give its sub-states. The electron transitions from these substituent energy levels give additional spectral lines. These are known as fine structures of the main spectral line. The hydrogen spectrum exhibiting the fine structured lines is known as the hydrogen fine spectrum.
For more information on this topic, kindly visit our blog article at;
https://jayamchemistrylearners.blogspot.com/2022/04/fine-structure-of-hydrogen-atom.html
The document discusses various topics related to lasers including pumping processes, laser safety rules, optical pumping, transverse and longitudinal modes, and types of lasers. It explains that pumping involves transferring energy into the gain medium of a laser to produce population inversion allowing for stimulated emission. Optical pumping was developed in the 1950s by Alfred Kastler and involves using light to excite electrons. Common pump sources include laser diodes and flash lamps. Lasers have transverse and longitudinal modes that determine the emission spectrum. Different types of lasers discussed include gas dynamic lasers, chemical lasers, and TEM microscopes.
Galaxies come in different shapes and sizes. The largest are spiral galaxies which have a flattened disk with spiral arms and a bulge in the center. Elliptical galaxies have no definite shape and little gas or dust. Irregular galaxies have an irregular shape and active star formation. Well-known galaxies include the Andromeda Galaxy, Whirlpool Galaxy, Sombrero Galaxy, and Sunflower Galaxy.
Dark matter is invisible matter that makes up about 21% of the universe. It cannot be seen directly but its existence and properties are known through its gravitational effects on visible matter. There are two main types of dark matter: ordinary matter made up of normal particles and extraordinary dark matter like black holes. Dark matter was first proposed in 1933 by Fritz Zwicky to explain discrepancies in galaxy motions but its exact nature remains mysterious. Current experiments aim to detect dark matter particles but have had conflicting results so far.
1. The document discusses different units used to measure astronomical distances, including the astronomical unit (AU), light year, and parsec.
2. It explains how parallax can be used to measure distances to stars by observing the apparent shift in position of a star relative to background objects as the Earth orbits the Sun.
3. Spectroscopic parallax and studying Cepheid variable stars can also be used to determine distances. Analyzing a star's spectrum provides information to estimate its luminosity and place it on the Hertzsprung-Russell diagram to find distance.
A star is a ball of plasma held together by gravity that undergoes nuclear fusion at its core, releasing electromagnetic radiation. Stars exist along a spectrum from hot, blue stars to cooler, red stars and can be classified based on their temperature, luminosity, and color. A star's life cycle begins as a contracting nebula and progresses through stages such as the main sequence, red giant, planetary nebula, and white dwarf before ending as a neutron star or black hole.
1. Stars form from dense clouds of gas and dust in interstellar space.
2. Gravity causes the cloud to contract over many stages until fusion begins in the core and a new star is born on the main sequence.
3. The size and mass of a star determines its position on the HR diagram, with more massive stars being larger and hotter.
This document discusses metamaterials and their applications in superlensing and cloaking. It begins by explaining Victor Veselago's proposal in the 1960s that a material with negative permeability and permittivity could bend light backwards. In the 2000s, Pendry and Smith created metamaterials with engineered electromagnetic responses at subwavelength scales that demonstrated negative refraction. This led to the development of the superlens, which can overcome the diffraction limit and image objects smaller than the wavelength of light used. The document also discusses how transformation optics allows for the design of cloaking materials that bend light around objects, rendering them invisible.
Chapter 11 discusses the interstellar medium and star formation. The interstellar medium consists of gas and dust between the stars. Emission nebulae are hot glowing gas associated with large star formation, while dark dust clouds are very cold molecular clouds where star formation may begin. Stars form from collapsing fragments of dust and gas clouds over many stages, with the core heating up until nuclear fusion can begin and the star reaches the main sequence. The mass of a star determines its position on the main sequence. Star clusters form when a single cloud produces many stars of similar age and composition.
Astronomy is the scientific study of celestial objects and phenomena that originate outside the Earth's atmosphere. In modern times, astronomy is defined as the science of the universe outside of Earth. Key areas of astronomy include cosmology, astrometry, planetology, and radio astronomy. Optical telescopes use lenses to collect and focus light, while radio telescopes use large concave mirrors. Other instruments like spectroscopes, photometers, and interferometers are also used. The universe originated from a massive expansion known as the Big Bang, and theories about its future evolution and structure continue to be explored. Galaxies, stars, and planetary systems are some of the main components of the universe studied by astronomers.
1. Stellar parallax is a method used to measure the distances to nearby stars by observing how their positions shift relative to more distant background stars over the course of 6 months as Earth orbits the Sun.
2. When starlight is passed through a prism or spectroscope, it is separated into a spectrum of colors that can reveal what chemical elements the star is made of. Different elements produce unique patterns of spectral lines.
3. By analyzing the absorption line spectra of stars, astronomers have identified over 70 chemical elements present in stars including hydrogen, helium, and metals like iron. A star's temperature can also be estimated from its spectral class.
1. The document describes the motions of objects in the sky and our location in the universe, including a description of the Milky Way galaxy and our solar system.
2. Key concepts covered include the coordinate systems used to locate celestial objects, precession of the Earth, and the causes of the seasons due to the tilt of the Earth's axis.
3. Motions of objects like the sun and stars are explained, including how the sun appears to move along the ecliptic and causes the seasons as the Earth orbits around it.
A supernova is a massive stellar explosion that occurs at the end of a large star's life. There are two main types of supernovae that can form - Type I occurs when a white dwarf star accumulates too much matter from a nearby star, and Type II occurs when a massive star runs out of nuclear fuel and collapses under its own gravity. During its explosion, a supernova can outshine its entire host galaxy and radiate more energy than our Sun will over its entire lifetime, making them the primary source of heavy elements in the universe.
The document discusses the four fundamental forces: gravitational, electromagnetic, nuclear, and weak. It summarizes that the nuclear force was discovered after neutrons were discovered in 1932, and holds nucleons together in the nucleus. The nuclear force is charge independent, very strong but short range, repulsive at short distances, and acts through the exchange of pions between nucleons. The document provides details on the Yukawa potential and uncertainty principle as they relate to the nuclear force. It poses a multiple choice question about identifying an incorrect statement regarding the nuclear force.
The Sun formed around 5 billion years ago from a cloud of gas and dust. Through the process of nuclear fusion at its core, the Sun generates immense heat and light by converting hydrogen into helium. It is a common yellow star that is part of a cycle that creates convection currents within its surface and sunspots that follow an 11-year cycle. The Sun provides the energy necessary to sustain life on Earth but will eventually exhaust its hydrogen fuel in around 5 billion years.
1) A matéria negra compõe cerca de 23% da densidade de energia do universo e interage apenas gravitacionalmente.
2) O destino final do universo depende da quantidade total de matéria, sendo possível um Big Rip ou Big Crunch.
3) Experimentos no CERN sugeriram que neutrinos viajaram mais rápido que a luz, o que desafiaria a teoria da relatividade, embora possa ser explicado por dimensões extras.
Interference occurs when two waves superimpose to form a resultant wave of greater or lower amplitude. There are two main types of interference: constructive and destructive. Constructive interference occurs when wave crests or troughs overlap, increasing amplitude, while destructive interference occurs when a crest and trough overlap, decreasing amplitude. Thin film interference is studied using thin films that reflect light, which can interfere and be analyzed to determine properties like film thickness. Interferometers exploit the interference of light to make extremely precise measurements of distance and other values.
IB Astrophysics - stellar radiation and types - Flippingphysics by nothingnerdyNothingnerdy
This document discusses stellar radiation and stellar classification. Stars are classified based on their temperature, which is determined from their blackbody spectrum. Hotter stars have shorter peak wavelengths and are classified as O, B, A types while cooler stars like K and M types have longer peak wavelengths. A star's luminosity and temperature are correlated on the Hertzsprung-Russell diagram, with the main sequence containing the bulk of stars.
This document provides an introduction to particle physics, including:
- A brief history of discoveries of the elementary constituents of matter like protons, neutrons, electrons.
- An overview of the four fundamental forces and how they control particle behavior.
- Explanations of conservation laws, neutrino theory, and early experiments verifying mass-energy equivalence.
- Descriptions of the Standard Model of particle families, forces, the quark model, and antimatter discoveries.
This document provides a summary of stellar evolution from the birth of stars to their death. It discusses how stars are formed inside nebulae from collapsing gas clouds. As stars age, they progress through different stages such as protostars, T-Tauri stars, and red giants. More massive stars may die in supernova explosions, leaving behind neutron stars or black holes. Lower mass stars end as white dwarfs. The document also describes different types of nebulae and compact objects like neutron stars and black holes.
Planetary nebulae form during the late stages of evolution for low-to-medium mass stars. As a star expands into a red giant, it ejects its outer layers through pulsations and stellar winds. The hot core ionizes the ejected gas, causing it to glow brightly. This energized shell of nebulous gas appears as a planetary nebula. Examples are the Helix Nebula and Ring Nebula. More massive stars may explode as supernovae, leaving behind neutron stars or black holes, depending on the star's original mass. The document discusses these stages of stellar evolution and death that give rise to different astronomical phenomena like planetary nebulae and neutron stars.
This document provides an overview of elementary particles. It discusses their classification into baryons, leptons, and mesons. Baryons include protons, neutrons, and heavier hyperons. Leptons contain electrons, photons, neutrinos, and muons. Mesons have masses between baryons and leptons. Each particle is described along with its properties. The document also discusses particles and their antiparticles, and conservation laws related to parity, charge conjugation, time reversal, and the combined CPT symmetry.
The splitting of the main spectral line into two or more components with a slight variation in wavelength in the magnetic field is called fine structure in spectroscopy. It means that, in the magnetic field, the electron energy splits to give its sub-states. The electron transitions from these substituent energy levels give additional spectral lines. These are known as fine structures of the main spectral line. The hydrogen spectrum exhibiting the fine structured lines is known as the hydrogen fine spectrum.
For more information on this topic, kindly visit our blog article at;
https://jayamchemistrylearners.blogspot.com/2022/04/fine-structure-of-hydrogen-atom.html
The document discusses various topics related to lasers including pumping processes, laser safety rules, optical pumping, transverse and longitudinal modes, and types of lasers. It explains that pumping involves transferring energy into the gain medium of a laser to produce population inversion allowing for stimulated emission. Optical pumping was developed in the 1950s by Alfred Kastler and involves using light to excite electrons. Common pump sources include laser diodes and flash lamps. Lasers have transverse and longitudinal modes that determine the emission spectrum. Different types of lasers discussed include gas dynamic lasers, chemical lasers, and TEM microscopes.
Galaxies come in different shapes and sizes. The largest are spiral galaxies which have a flattened disk with spiral arms and a bulge in the center. Elliptical galaxies have no definite shape and little gas or dust. Irregular galaxies have an irregular shape and active star formation. Well-known galaxies include the Andromeda Galaxy, Whirlpool Galaxy, Sombrero Galaxy, and Sunflower Galaxy.
Dark matter is invisible matter that makes up about 21% of the universe. It cannot be seen directly but its existence and properties are known through its gravitational effects on visible matter. There are two main types of dark matter: ordinary matter made up of normal particles and extraordinary dark matter like black holes. Dark matter was first proposed in 1933 by Fritz Zwicky to explain discrepancies in galaxy motions but its exact nature remains mysterious. Current experiments aim to detect dark matter particles but have had conflicting results so far.
1. The document discusses different units used to measure astronomical distances, including the astronomical unit (AU), light year, and parsec.
2. It explains how parallax can be used to measure distances to stars by observing the apparent shift in position of a star relative to background objects as the Earth orbits the Sun.
3. Spectroscopic parallax and studying Cepheid variable stars can also be used to determine distances. Analyzing a star's spectrum provides information to estimate its luminosity and place it on the Hertzsprung-Russell diagram to find distance.
A star is a ball of plasma held together by gravity that undergoes nuclear fusion at its core, releasing electromagnetic radiation. Stars exist along a spectrum from hot, blue stars to cooler, red stars and can be classified based on their temperature, luminosity, and color. A star's life cycle begins as a contracting nebula and progresses through stages such as the main sequence, red giant, planetary nebula, and white dwarf before ending as a neutron star or black hole.
1. Stars form from dense clouds of gas and dust in interstellar space.
2. Gravity causes the cloud to contract over many stages until fusion begins in the core and a new star is born on the main sequence.
3. The size and mass of a star determines its position on the HR diagram, with more massive stars being larger and hotter.
This document discusses metamaterials and their applications in superlensing and cloaking. It begins by explaining Victor Veselago's proposal in the 1960s that a material with negative permeability and permittivity could bend light backwards. In the 2000s, Pendry and Smith created metamaterials with engineered electromagnetic responses at subwavelength scales that demonstrated negative refraction. This led to the development of the superlens, which can overcome the diffraction limit and image objects smaller than the wavelength of light used. The document also discusses how transformation optics allows for the design of cloaking materials that bend light around objects, rendering them invisible.
Chapter 11 discusses the interstellar medium and star formation. The interstellar medium consists of gas and dust between the stars. Emission nebulae are hot glowing gas associated with large star formation, while dark dust clouds are very cold molecular clouds where star formation may begin. Stars form from collapsing fragments of dust and gas clouds over many stages, with the core heating up until nuclear fusion can begin and the star reaches the main sequence. The mass of a star determines its position on the main sequence. Star clusters form when a single cloud produces many stars of similar age and composition.
Astronomy is the scientific study of celestial objects and phenomena that originate outside the Earth's atmosphere. In modern times, astronomy is defined as the science of the universe outside of Earth. Key areas of astronomy include cosmology, astrometry, planetology, and radio astronomy. Optical telescopes use lenses to collect and focus light, while radio telescopes use large concave mirrors. Other instruments like spectroscopes, photometers, and interferometers are also used. The universe originated from a massive expansion known as the Big Bang, and theories about its future evolution and structure continue to be explored. Galaxies, stars, and planetary systems are some of the main components of the universe studied by astronomers.
1. Stellar parallax is a method used to measure the distances to nearby stars by observing how their positions shift relative to more distant background stars over the course of 6 months as Earth orbits the Sun.
2. When starlight is passed through a prism or spectroscope, it is separated into a spectrum of colors that can reveal what chemical elements the star is made of. Different elements produce unique patterns of spectral lines.
3. By analyzing the absorption line spectra of stars, astronomers have identified over 70 chemical elements present in stars including hydrogen, helium, and metals like iron. A star's temperature can also be estimated from its spectral class.
This chapter discusses atomic physics and spectra. It explains that stars with different surface temperatures emit different wavelengths of electromagnetic radiation, allowing astronomers to determine the chemical compositions of stars and interstellar clouds. Spectroscopy provides information about distant astronomical objects by analyzing their characteristic spectral lines. The temperature of a star can be estimated by examining the intensity of light across wavelengths, as hotter stars emit more radiation and peak at shorter wavelengths according to blackbody radiation laws.
Dark side ofthe_universe_public_29_september_2017_nazarbayev_shrtZhaksylyk Kazykenov
1) The document discusses the history of discoveries about the universe, from ancient cosmologies to modern precision cosmology. Key developments include realizing the sun is at the center of the solar system, discovering other galaxies and the expansion of the universe, and detecting the cosmic microwave background and dark matter.
2) Current open questions about the universe include the nature of dark matter and dark energy. Observations show dark energy is accelerating the expansion of the universe, but its underlying cause remains unknown. Precise measurements aim to distinguish between models of dark energy.
3) The standard cosmological model has been very successful in explaining observations but has fine-tuning problems regarding why the present epoch is dominated by both matter and dark energy.
This document provides summaries of 15 astronomical images in 3 sentences or less. It describes various celestial objects like galaxies, nebulae, star clusters and more. The summaries concisely highlight the key features and phenomena shown in each full-color image from NASA telescopes and observatories.
Nebulae are clouds of gas and dust in space. There are several types including dark nebulae which appear black, reflection nebulae which glow blue from reflected starlight, and emission nebulae which glow in specific colors due to ionized gas. Quasars are extremely bright active galactic nuclei containing supermassive black holes. The first quasar, 3C 273, was discovered in the 1960s and found to be billions of light years away. Blazars are a type of quasar that emit most of their energy as gamma rays and X-rays. Quasars can be thousands of times brighter than entire galaxies and contain disks of superhot gas and jets of matter near supermassive black holes.
The document discusses the discoveries of Takaaki Kajita and Arthur B. McDonald, who were awarded the 2015 Nobel Prize in Physics. Their research groups at Super-Kamiokande (Japan) and Sudbury Neutrino Observatory (Canada) discovered that neutrinos change identities in flight through a process called neutrino oscillation. This revealed that neutrinos must have a small but non-zero mass, challenging the Standard Model of particle physics. The experiments found that muon neutrinos transformed into tau neutrinos over long distances, and that solar electron neutrinos transformed into other types of neutrinos during their journey from the Sun to Earth. These findings opened a new realm in particle physics and transformed understanding of the universe.
The document discusses various topics relating to stellar characteristics and evolution. It begins by explaining blackbody radiation and Wien's law, which show the relationship between an object's temperature and the wavelength of its peak emission. This allows astronomers to determine a star's surface temperature from its spectrum. The rest of the document discusses stellar classification schemes, the Hertzsprung-Russell diagram, the life cycles of different types of stars such as red giants and white dwarfs, and phenomena like supernovae, pulsars, and binary star systems. Spectral analysis provides insights into stellar physics and evolution.
Form 3 PMR Science Chapter 9 Stars and GalaxiesSook Yen Wong
Stars are giant balls of hot gases that produce heat and light through nuclear fusion reactions in their cores. Stars are classified according to attributes like temperature, brightness, chemical composition, size, and density. When stars die, they may leave behind white dwarfs, neutron stars, or black holes. Galaxies contain millions of stars and come in different shapes like spiral and elliptical.
The document summarizes key concepts in astronomy, including:
- Astronomy is the study of objects outside Earth, while astrology uses celestial objects to predict events.
- Light and other electromagnetic radiation provide information about distant stars and galaxies. Spectral analysis reveals the composition of stars.
- The universe is immense, with distances measured in light years due to the finite speed of light. Stars have different properties based on size, temperature, brightness, and more.
- Stars evolve over their lifetime according to nuclear fusion processes in their cores until ending as white dwarfs, neutron stars, or black holes depending on their mass.
- Galaxies come in spiral, elliptical, and irregular forms, with the Milky Way
1. The document discusses astronomy and the electromagnetic spectrum, including how stars emit radiation at different temperatures and wavelengths.
2. It explains that in the sun, hydrogen atoms fuse into helium through nuclear fusion, producing radiation in the visible light range.
3. Various parts of the electromagnetic spectrum, such as radio, infrared, optical, x-ray, and gamma ray astronomy are used to study different astronomical objects and gather information.
The James Webb Space Telescope is NASA's next flagship mission. Webb will revolutionize astronomy in the infrared like the Hubble Space Telescope has done for the visible portion of the spectrum over the last 22 years. Webb will reveal the story of the formation of the first starts and galaxies, investigate the processes of planet formation, and trace the origins of life.
The document discusses the discovery of the Milky Way galaxy. It describes how in the early 20th century, Shapley and Curtis debated whether spiral nebulae were inside or outside our galaxy. Hubble later proved with Cepheid variables that they were actually other galaxies. The Milky Way is now understood to be a barred spiral galaxy about 30,000 light years wide, with a bulge, disk containing spiral arms, and halo of globular clusters. It formed from a cloud of gas that contracted under gravity and began rotating to form the spiral structure seen today.
The document describes different types of stars:
1) Red giants are very large, cool stars that all main sequence stars evolve into. Nuclear fusion occurs in red giants, fusing helium into heavier elements.
2) White dwarfs are very small and dense remnants of red giants. They have high temperatures but low luminosities due to their small size.
3) Neutron stars form from massive stars and are very hot and dense, composed mostly of neutrons. Pulsars are rotating, magnetized neutron stars that emit beams of electromagnetic radiation.
Comets are small icy bodies that orbit the sun in elliptical orbits and consist of dust and frozen gases. There are over 650 known comets that range in size from 42 miles to 0.3 miles in diameter. As comets pass near the sun, their ice sublimates and forms a coma of dust and gas around the nucleus. Asteroids are smaller rocky bodies that orbit mainly in the asteroid belt between Mars and Jupiter. Meteors are small rocky objects that burn up as meteors or meteorites when entering the Earth's atmosphere. The document discusses properties of stars like magnitude, color, composition and distance measurement techniques. It describes groupings of stars like clusters, associations and galaxies. Various astronomical instruments used to
- 99% of the universe is believed to be dark matter. Scientists are convinced that only 1% of the 5% of baryonic matter present in the universe can be seen.
- Evidence has accumulated that there is more matter in galaxies than what meets the eye through telescopes. As much as 90% of the matter in the universe must be in some "dark" form.
- Observations of galaxy rotation curves showed that stars at the outer edges of galaxies move at the same speed as inner stars, even though there isn't enough visible matter to account for the gravitational force needed to keep them in orbit, suggesting additional unseen "dark matter" is present.
The document discusses three mysteries: auroras, black holes and cosmic X-rays, and comets. It provides background on each mystery and notes that auroras involve distinct magnetosphere processes, black holes can be studied through polarized X-ray measurements, and comets may have brought water to Earth and studying comet material may reveal secrets about the origins of the universe.
A black hole is a region of space where the gravitational field is so strong that nothing, not even light, can escape. Black holes form during the gravitational collapse of massive stars or supermassive stars. Once formed, black holes can be detected through their interaction with nearby matter like stars or gas, as the matter orbits or falls into the black hole. The existence of black holes is now widely accepted based on both theoretical predictions and observational evidence like detecting radiation emitted by matter falling into stellar-mass black holes or observing the effects of supermassive black holes on their host galaxies.
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Chapter wise All Notes of First year Basic Civil Engineering.pptxDenish Jangid
Chapter wise All Notes of First year Basic Civil Engineering
Syllabus
Chapter-1
Introduction to objective, scope and outcome the subject
Chapter 2
Introduction: Scope and Specialization of Civil Engineering, Role of civil Engineer in Society, Impact of infrastructural development on economy of country.
Chapter 3
Surveying: Object Principles & Types of Surveying; Site Plans, Plans & Maps; Scales & Unit of different Measurements.
Linear Measurements: Instruments used. Linear Measurement by Tape, Ranging out Survey Lines and overcoming Obstructions; Measurements on sloping ground; Tape corrections, conventional symbols. Angular Measurements: Instruments used; Introduction to Compass Surveying, Bearings and Longitude & Latitude of a Line, Introduction to total station.
Levelling: Instrument used Object of levelling, Methods of levelling in brief, and Contour maps.
Chapter 4
Buildings: Selection of site for Buildings, Layout of Building Plan, Types of buildings, Plinth area, carpet area, floor space index, Introduction to building byelaws, concept of sun light & ventilation. Components of Buildings & their functions, Basic concept of R.C.C., Introduction to types of foundation
Chapter 5
Transportation: Introduction to Transportation Engineering; Traffic and Road Safety: Types and Characteristics of Various Modes of Transportation; Various Road Traffic Signs, Causes of Accidents and Road Safety Measures.
Chapter 6
Environmental Engineering: Environmental Pollution, Environmental Acts and Regulations, Functional Concepts of Ecology, Basics of Species, Biodiversity, Ecosystem, Hydrological Cycle; Chemical Cycles: Carbon, Nitrogen & Phosphorus; Energy Flow in Ecosystems.
Water Pollution: Water Quality standards, Introduction to Treatment & Disposal of Waste Water. Reuse and Saving of Water, Rain Water Harvesting. Solid Waste Management: Classification of Solid Waste, Collection, Transportation and Disposal of Solid. Recycling of Solid Waste: Energy Recovery, Sanitary Landfill, On-Site Sanitation. Air & Noise Pollution: Primary and Secondary air pollutants, Harmful effects of Air Pollution, Control of Air Pollution. . Noise Pollution Harmful Effects of noise pollution, control of noise pollution, Global warming & Climate Change, Ozone depletion, Greenhouse effect
Text Books:
1. Palancharmy, Basic Civil Engineering, McGraw Hill publishers.
2. Satheesh Gopi, Basic Civil Engineering, Pearson Publishers.
3. Ketki Rangwala Dalal, Essentials of Civil Engineering, Charotar Publishing House.
4. BCP, Surveying volume 1
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3. Spectroscopy
Spectroscopy is a technique in which the visible
light that comes from objects (like stars and
nebulae) is examined to determine the object's
composition, temperature, motion, and
density.
A representation of the spectrum of a compound
4. When something is hot enough to glow (like a star), it
gives us information about what it is made of, because
different substances give off a different spectrum of
light when they vaporize. Each substance produces a
unique spectrum, almost like a fingerprint.
In addition, different cool gases will absorb different
wavelengths of light and generate a signature spectrum
with dark lines at characteristic places. Because of
this, we can determine the composition of gases by
observing light that has passed through them.
The spectrum of Hydrogen gas
7. Astronomical Spectroscopy
It is the use of spectroscopy in astronomy.
In this, spectroscopy is used to derive many properties of
stars and galaxies, such as their composition and
movement.
Astronomical
spectroscopy
began with Isaac
Newton's initial
observations of
the light of the
Sun, dispersed by
a prism.
Dispersion of light by a prism
8. However, when the spectrum was closely examined, the
rainbow was found to be interrupted by hundreds of tiny
dark lines (called Fraunhofer lines). These lines showed
that some wavelengths are being absorbed by gases in
the outer atmosphere of the Sun, and from this, we can
determine which elements are in the Sun's atmosphere.
Extremely high resolution spectrum of the Sun
9. Discovery of Helium
In 1868, Sir Norman Lockyer
observed strong yellow lines in
the solar spectrum which had
never been seen in laboratory
experiments. He deduced that
they must be due to an unknown Norman Lockyer spectroscope
element, which he called
helium, from the Greek helios
(sun)
It was only 25 years later (in the
1890s) that Helium was detected
on earth. Helium in Solar Prominences
10. Spectral types
The spectral type of stars is a system of classification of stars
based on the stars' spectra that correlate with each star's
surface temperature and color.
Stars range from blue
and hot to red and cool.
The seven spectral
types are:
O, B, A, F, G, K, and M
(from hottest to
coolest). Each of these
letters is divided into 10
numerical classes, from
hotter to cooler:
The sun’s spectral type is G2 0, 1, 2, 3, 4, 5, 6, 7, 8, an
d 9.
11. Nebulae
In earlier times, the word ‘nebula’ was used to describe
any fuzzy patch of light that didn’t look like a star.
However, when their spectra were studied, it was found
that many of these nebulae, such as the Andromeda
Nebula, had spectra that looked similar to stellar
spectra, and these turned out to be galaxies.
12. Others, such as the Cat’s Eye Nebula, had very different spectra –
consisting of a few strong emission lines rather than the
continuous spectrum seen in the sun.
These lines did not
correspond to any element
seen on Earth, and
astronomers suggested
them to be from a new
element nebulium.
However, later studies
showed that because of the
extremely rarified vacuum
found in nebulae, atoms
The Cat’s Eye Nebula behaved
differently, leading to the
strange spectrum.
13. Galaxies
Galactic spectroscopy has led to many fundamental
discoveries. Edwin Hubble discovered in the 1920s
that, apart from the nearest ones (those in what is known
as the Local Group), all galaxies are receding from the
Earth. The further away a galaxy, the faster it is receding.
This was the first indication that the universe originated
from a single point, in a Big Bang.
14. Planets and Asteroids
Planets and asteroids shine only by
reflecting the light of their parent
star.
The reflected light contains
absorption bands due to minerals in
the rocks present for rocky bodies, or
due to the elements and molecules
present in the atmospheres of the
Gas giants.
15. Asteroids can be classified into three main
types, according to their spectra: the C-types are made
of carbonaceous material, S-types consist mainly of
silicates, and M-types are 'metallic'. C- and S-type
asteroids are the most common.
16. Quasars
The distant nature of quasars were discovered in the
early 1960's, when their spectral lines were noted to be
substantially-shifted redder than they should normally
be.
This redshift was attributed to the recession (speeding
away) of quasars from us. Thus, it was concluded that
quasars were the most distant objects known to us.