AST101 Lecture 25 Why is the Night Sky Dark?
... Olber’s Paradox Suppose the universe is infinite • In whatever direction you look, you will see a star • The brightness of an individual star falls by the inverse square law: I ~ d-2 • The number of stars increases as d2 The night sky should be as bright as the surface of the Sun! ...
... Olber’s Paradox Suppose the universe is infinite • In whatever direction you look, you will see a star • The brightness of an individual star falls by the inverse square law: I ~ d-2 • The number of stars increases as d2 The night sky should be as bright as the surface of the Sun! ...
Gravity - Indiana University Astronomy
... a) The temperature of the gas when atoms formed from free electrons and nuclei was about 3000K. What would be the wavelength at which a gas of that temperature would emit the most energy? (Hint: Remember Wien’s Law, λmax = 2.9 x 106 / T(K), with in nanometers.) ...
... a) The temperature of the gas when atoms formed from free electrons and nuclei was about 3000K. What would be the wavelength at which a gas of that temperature would emit the most energy? (Hint: Remember Wien’s Law, λmax = 2.9 x 106 / T(K), with in nanometers.) ...
EM Spectrum Notes 2015-2016
... EM Spectrum Notes 2015-2016 blue shift objects moving towards Earth shorter wavelength ...
... EM Spectrum Notes 2015-2016 blue shift objects moving towards Earth shorter wavelength ...
Dark Matter - the stuff of the Universe?
... look for neutrino oscillations—change of neutrino type (depends on difference between masses of the two types) these do happen but the implied mass is very small indeed ...
... look for neutrino oscillations—change of neutrino type (depends on difference between masses of the two types) these do happen but the implied mass is very small indeed ...
Cosmic Dawn A Hunting for the First Stars in the Universe
... of these secondary elements backwards in time, we can infer the existence of generations of stars that have long since disappeared, in much the same way that an archeologist peels back geological strata to map the fossil record of extinct species. What astronomers call the “pollution” of the univer ...
... of these secondary elements backwards in time, we can infer the existence of generations of stars that have long since disappeared, in much the same way that an archeologist peels back geological strata to map the fossil record of extinct species. What astronomers call the “pollution” of the univer ...
Kg m/s2=SI(G) kg2/m2
... appears to be around 46x109 light-years not 13.7x109 light-years (as I had previously thought when I had neglected the acceleration of the universe), because the universe is not only expanding in space and advancing forward in time, but for the last several billion years the rate of expansion has be ...
... appears to be around 46x109 light-years not 13.7x109 light-years (as I had previously thought when I had neglected the acceleration of the universe), because the universe is not only expanding in space and advancing forward in time, but for the last several billion years the rate of expansion has be ...
Our Universe is big, beautiful… and mostly
... just one of billions of stars that make up our galaxy, which is called the Milky Way. When you think about how the Milky Way is just one galaxy in a group of about 40 nearby galaxies, the Universe is starting to seem like a big place! This new picture shows a different group of galaxies that is much ...
... just one of billions of stars that make up our galaxy, which is called the Milky Way. When you think about how the Milky Way is just one galaxy in a group of about 40 nearby galaxies, the Universe is starting to seem like a big place! This new picture shows a different group of galaxies that is much ...
Eye on the Sky - Sci-Port
... Key Terms: Universe: the totality of known or supposed objects and phenomena throughout space; the cosmos; macrocosm. Galaxy: a large system of stars held together by mutual gravitation and isolated from similar systems by vast regions of space. Black Hole: a massive object with zero volume and infi ...
... Key Terms: Universe: the totality of known or supposed objects and phenomena throughout space; the cosmos; macrocosm. Galaxy: a large system of stars held together by mutual gravitation and isolated from similar systems by vast regions of space. Black Hole: a massive object with zero volume and infi ...
The Solar System and our Universe
... • Provided evidence that throughout the universe stars are dying, and new stars & galaxies are constantly forming. ...
... • Provided evidence that throughout the universe stars are dying, and new stars & galaxies are constantly forming. ...
How will the universe end?
... particle density will go to zero – each particle will be cut off from the rest by a cosmological horizon – no interaction possible anymore A. Loeb: high-redshift sources will only be visible to us until they reach some finite age in their rest-frame ...
... particle density will go to zero – each particle will be cut off from the rest by a cosmological horizon – no interaction possible anymore A. Loeb: high-redshift sources will only be visible to us until they reach some finite age in their rest-frame ...
Getting to Know: Evidence for the Big Bang Theory
... One type of evidence that has been used to support the Big Bang Theory is spectrum analysis. Spectrum analysis involves studying the wavelengths of light in the universe. We can study the wavelength of light from distant stars and galaxies to draw conclusions about their movement. For example, if ob ...
... One type of evidence that has been used to support the Big Bang Theory is spectrum analysis. Spectrum analysis involves studying the wavelengths of light in the universe. We can study the wavelength of light from distant stars and galaxies to draw conclusions about their movement. For example, if ob ...
![cosmology[1] - KarenConnerEnglishIV](http://s1.studyres.com/store/data/002375580_1-efbe19cf7c791439d3765f11461d68f5-300x300.png)
cosmology[1] - KarenConnerEnglishIV
... but like Cepheids, the faster ones are dimmer, so we can figure out how absolute magniitude seeing how fast they vary That enabled two different teams to measure the distance to each supernova. Distance is also an indicator of time since we observe a supernova 5 billion light years away as it appear ...
... but like Cepheids, the faster ones are dimmer, so we can figure out how absolute magniitude seeing how fast they vary That enabled two different teams to measure the distance to each supernova. Distance is also an indicator of time since we observe a supernova 5 billion light years away as it appear ...
Alexander Polnarev QMUL, SPA 28 March 2014
... March 17: The announcement by the BICEP2 collaboration of the first indirect detection of primordial gravitational waves, an important prediction of the theory. The BICEP2 collaboration is an international team of astronomers working at the South Pole. If confirmed by other ongoing experiments, the ...
... March 17: The announcement by the BICEP2 collaboration of the first indirect detection of primordial gravitational waves, an important prediction of the theory. The BICEP2 collaboration is an international team of astronomers working at the South Pole. If confirmed by other ongoing experiments, the ...
cosmology-2005
... the last months of thesis work. I joined Bell Laboratories at Crawford Hill in 1963 as part of A.B. Crawford's Radio Research department in R. Kompfner's laboratory. I started working with the only other radio astronomer, Arno Penzias, who had been there about two years. ...
... the last months of thesis work. I joined Bell Laboratories at Crawford Hill in 1963 as part of A.B. Crawford's Radio Research department in R. Kompfner's laboratory. I started working with the only other radio astronomer, Arno Penzias, who had been there about two years. ...
Chapter 2 Basic Chemistry
... telescopes to study the most distant objects, whose light was emitted billions of years ago. – By studying this ancient light and looking at other evidence, scientists have been able to theorize that the Universe formed during a cataclysmic event known as the big bang ...
... telescopes to study the most distant objects, whose light was emitted billions of years ago. – By studying this ancient light and looking at other evidence, scientists have been able to theorize that the Universe formed during a cataclysmic event known as the big bang ...
Chapter 7
... To a surprising degree of accuracy we can assume that the Universe behaves adiabatically, i.e. during the expansion we can assume that all processes are reversible. And it also turns out that we can understand many of the thermal processes in the early universe with thermal equilibrium followed by “ ...
... To a surprising degree of accuracy we can assume that the Universe behaves adiabatically, i.e. during the expansion we can assume that all processes are reversible. And it also turns out that we can understand many of the thermal processes in the early universe with thermal equilibrium followed by “ ...
PowerPoint Presentation - The Origin of the Universe
... 3.6% is baryonic matter About 30% is dark matter Rest (about 70%) is dark energy! ...
... 3.6% is baryonic matter About 30% is dark matter Rest (about 70%) is dark energy! ...
0708 - Astronomy
... If the Universe is expanding, does that also mean that the Galaxy and the Solar system are expanding? ...
... If the Universe is expanding, does that also mean that the Galaxy and the Solar system are expanding? ...
Where do we come from?
... The earliest stars contain 75% hydrogen, 25% helium, as predicted from primordial nucleosynthesis. (Later stars contain more helium, made in previous generations of stars.) ...
... The earliest stars contain 75% hydrogen, 25% helium, as predicted from primordial nucleosynthesis. (Later stars contain more helium, made in previous generations of stars.) ...
Lecture 24 Early Universe
... The names of quark flavours (up, down, strange, charm, bottom, and top) were also chosen arbitrarily based on the need to name them something that could be easily remembered and used. An important property of quarks is called confinement, which states that individual ...
... The names of quark flavours (up, down, strange, charm, bottom, and top) were also chosen arbitrarily based on the need to name them something that could be easily remembered and used. An important property of quarks is called confinement, which states that individual ...
Back ground information
... Visible light has more energy and smaller wavelengths than infrared radiation and is divided into the different colors humans see. Moving from longer wavelengths (less energy) to shorter wavelengths (more energy) one finds red, orange, yellow, green, blue, and violet. The color of the light emitted ...
... Visible light has more energy and smaller wavelengths than infrared radiation and is divided into the different colors humans see. Moving from longer wavelengths (less energy) to shorter wavelengths (more energy) one finds red, orange, yellow, green, blue, and violet. The color of the light emitted ...
Cosmology
... Describe and explain asteroids and meteorites and that these usually vaporize on entering the Earth’s atmosphere. Binary stars- most stars are part of a binary system and rotate around their common centre of mass. The Big Bang Discuss cosmic background radiation and its discovery. Talk about the sig ...
... Describe and explain asteroids and meteorites and that these usually vaporize on entering the Earth’s atmosphere. Binary stars- most stars are part of a binary system and rotate around their common centre of mass. The Big Bang Discuss cosmic background radiation and its discovery. Talk about the sig ...
Cosmic microwave background
The cosmic microwave background (CMB) is the thermal radiation left over from the time of recombination in Big Bang cosmology. In older literature, the CMB is also variously known as cosmic microwave background radiation (CMBR) or ""relic radiation."" The CMB is a cosmic background radiation that is fundamental to observational cosmology because it is the oldest light in the universe, dating to the epoch of recombination. With a traditional optical telescope, the space between stars and galaxies (the background) is completely dark. However, a sufficiently sensitive radio telescope shows a faint background glow, almost exactly the same in all directions, that is not associated with any star, galaxy, or other object. This glow is strongest in the microwave region of the radio spectrum. The accidental discovery of CMB in 1964 by American radio astronomers Arno Penzias and Robert Wilson was the culmination of work initiated in the 1940s, and earned the discoverers the 1978 Nobel Prize.The CMB is a snapshot of the oldest light in our Universe, imprinted on the sky when the Universe was just 380,000 years old. It shows tiny temperature fluctuations that correspond to regions of slightly different densities, representing the seeds of all future structure: the stars and galaxies of today.The CMB is well explained as radiation left over from an early stage in the development of the universe, and its discovery is considered a landmark test of the Big Bang model of the universe. When the universe was young, before the formation of stars and planets, it was denser, much hotter, and filled with a uniform glow from a white-hot fog of hydrogen plasma. As the universe expanded, both the plasma and the radiation filling it grew cooler. When the universe cooled enough, protons and electrons combined to form neutral atoms. These atoms could no longer absorb the thermal radiation, and so the universe became transparent instead of being an opaque fog. Cosmologists refer to the time period when neutral atoms first formed as the recombination epoch, and the event shortly afterwards when photons started to travel freely through space rather than constantly being scattered by electrons and protons in plasma is referred to as photon decoupling. The photons that existed at the time of photon decoupling have been propagating ever since, though growing fainter and less energetic, since the expansion of space causes their wavelength to increase over time (and wavelength is inversely proportional to energy according to Planck's relation). This is the source of the alternative term relic radiation. The surface of last scattering refers to the set of points in space at the right distance from us so that we are now receiving photons originally emitted from those points at the time of photon decoupling.Precise measurements of the CMB are critical to cosmology, since any proposed model of the universe must explain this radiation. The CMB has a thermal black body spectrum at a temperature of 7000272548000000000♠2.72548±0.00057 K. The spectral radiance dEν/dν peaks at 160.2 GHz, in the microwave range of frequencies. (Alternatively if spectral radiance is defined as dEλ/dλ then the peak wavelength is 1.063 mm.) The glow is very nearly uniform in all directions, but the tiny residual variations show a very specific pattern, the same as that expected of a fairly uniformly distributed hot gas that has expanded to the current size of the universe. In particular, the spectral radiance at different angles of observation in the sky contains small anisotropies, or irregularities, which vary with the size of the region examined. They have been measured in detail, and match what would be expected if small thermal variations, generated by quantum fluctuations of matter in a very tiny space, had expanded to the size of the observable universe we see today. This is a very active field of study, with scientists seeking both better data (for example, the Planck spacecraft) and better interpretations of the initial conditions of expansion. Although many different processes might produce the general form of a black body spectrum, no model other than the Big Bang has yet explained the fluctuations. As a result, most cosmologists consider the Big Bang model of the universe to be the best explanation for the CMB.The high degree of uniformity throughout the observable universe and its faint but measured anisotropy lend strong support for the Big Bang model in general and the ΛCDM (""Lambda Cold Dark Matter"") model in particular. Moreover, the fluctuations are coherent on angular scales that are larger than the apparent cosmological horizon at recombination. Either such coherence is acausally fine-tuned, or cosmic inflation occurred.