Brock physics - Brock University
... (c) the radius of the region around a neutron star within which X-ray bursts occur. (d) * the radius of the region around a black hole within which not even light can escape. 35. Neutron stars with masses greater than about 3 solar masses do not exist because neutron degeneracy pressure is not stron ...
... (c) the radius of the region around a neutron star within which X-ray bursts occur. (d) * the radius of the region around a black hole within which not even light can escape. 35. Neutron stars with masses greater than about 3 solar masses do not exist because neutron degeneracy pressure is not stron ...
lecture21
... The laws of general relativity modify the way objects move near large masses (relative to their Newtonian motion). For example, Mercury’s orbit close to the sun is changed so that its perihelion ‘precesses’ with time. The precession of Mercury’s orbit due to general relativity is only 43 arc seconds ...
... The laws of general relativity modify the way objects move near large masses (relative to their Newtonian motion). For example, Mercury’s orbit close to the sun is changed so that its perihelion ‘precesses’ with time. The precession of Mercury’s orbit due to general relativity is only 43 arc seconds ...
ASTRONOMY: WHAT DO YOU NEED TO KNOW
... behind it. They don’t glow because there are no nearby stars to ionize the gas. What triggers star formation in an interstellar gas cloud? Shock waves from the explosions of nearby stars What is a protostar? A collapsing cloud of gas and dust destined to become a star but not yet glowing as a star W ...
... behind it. They don’t glow because there are no nearby stars to ionize the gas. What triggers star formation in an interstellar gas cloud? Shock waves from the explosions of nearby stars What is a protostar? A collapsing cloud of gas and dust destined to become a star but not yet glowing as a star W ...
James`s 5-Page Final Exam Review
... 27) Accelerations. Place a check mark next to each case that is an acceleration: a. My car going at a constant 25 miles per hour, while turning. b. My car going at a constant 25 miles per hour, while driving straight. c. My car increasing its speed from 25 miles per hour to 30 miles per hour. d. My ...
... 27) Accelerations. Place a check mark next to each case that is an acceleration: a. My car going at a constant 25 miles per hour, while turning. b. My car going at a constant 25 miles per hour, while driving straight. c. My car increasing its speed from 25 miles per hour to 30 miles per hour. d. My ...
ESOP August 2013
... Astronomical Research Institute of Thailand, [email protected] • He worked before for a long time at the European Southern Observatory, where he still makes most of his observations • Most observations are recorded in the infrared, allowing higher S/N and even some daytime observations • Observatio ...
... Astronomical Research Institute of Thailand, [email protected] • He worked before for a long time at the European Southern Observatory, where he still makes most of his observations • Most observations are recorded in the infrared, allowing higher S/N and even some daytime observations • Observatio ...
Distant Stars - How far away is it
... Remember the red and green light of the aurora borealis and the structure of molecules we discussed in our segment on the Heliosphere. The aurora is a good example of light being emitted as electrons change energy levels. But for our purposes here, we want to examine what happens when light from the ...
... Remember the red and green light of the aurora borealis and the structure of molecules we discussed in our segment on the Heliosphere. The aurora is a good example of light being emitted as electrons change energy levels. But for our purposes here, we want to examine what happens when light from the ...
SCI 103
... B) Only the planets whose orbits are larger in size than that of the Earth exhibit retrograde motion C) The planets orbit roughly in the ecliptic plane. D) Only planets whose orbits are smaller in size than that of the Earth exhibit a new phase for observers on or near the Earth. E) The planets rise ...
... B) Only the planets whose orbits are larger in size than that of the Earth exhibit retrograde motion C) The planets orbit roughly in the ecliptic plane. D) Only planets whose orbits are smaller in size than that of the Earth exhibit a new phase for observers on or near the Earth. E) The planets rise ...
Stars - Mrs. Tosh`s class
... The entire sky is lit up for weeks. The temperature can be more than 100 billion degrees. The iron atoms fuse into uranium. ...
... The entire sky is lit up for weeks. The temperature can be more than 100 billion degrees. The iron atoms fuse into uranium. ...
STAR FORMATION
... What would happen to a contracting cloud fragment if it were not able to radiate away its thermal energy? A. It would continue contracting, but its temperature would not change B. Its mass would increase C. Its internal pressure would increase ...
... What would happen to a contracting cloud fragment if it were not able to radiate away its thermal energy? A. It would continue contracting, but its temperature would not change B. Its mass would increase C. Its internal pressure would increase ...
Apparent Motions of Celestial Objects
... In the Northern Hemisphere: The Sun rises north of east and sets north of west in the summer. The sun’s altitude at noon is highest during the year. The sun’s “apparent path” across the sky is at its longest (greater than 12 hours). ...
... In the Northern Hemisphere: The Sun rises north of east and sets north of west in the summer. The sun’s altitude at noon is highest during the year. The sun’s “apparent path” across the sky is at its longest (greater than 12 hours). ...
Statistical challenges in modern astronomy
... “Essentially, all models are wrong, but some are useful.” (Box & Draper 1987) “There is no need for these hypotheses to be true, or even to be at all like the truth; rather … they should yield calculations which agree with observations” (Osiander’s Preface to Copernicus’ De Revolutionibus, quoted by ...
... “Essentially, all models are wrong, but some are useful.” (Box & Draper 1987) “There is no need for these hypotheses to be true, or even to be at all like the truth; rather … they should yield calculations which agree with observations” (Osiander’s Preface to Copernicus’ De Revolutionibus, quoted by ...
Ordinary Observer Principal Axioms applied to Electromagnetism
... The very same principal axioms of the logical addition of velocities also apply to the exchange of gravitons between particles of mass! The motion of a particle through the field set up by a different particle under the gravitational influence of the first, has a direct representation under the elec ...
... The very same principal axioms of the logical addition of velocities also apply to the exchange of gravitons between particles of mass! The motion of a particle through the field set up by a different particle under the gravitational influence of the first, has a direct representation under the elec ...
1 History of Astronomy - Journigan-wiki
... Brahe built a castle on Hven and named it Uraniborg after Urania, the goddess of the sky. He also built an observatory on the island. For over 20 years, Brahe used the island as his base from which to make astronomical observations. In 1597, Tycho Brahe lost the Danish king's support, so he went to ...
... Brahe built a castle on Hven and named it Uraniborg after Urania, the goddess of the sky. He also built an observatory on the island. For over 20 years, Brahe used the island as his base from which to make astronomical observations. In 1597, Tycho Brahe lost the Danish king's support, so he went to ...
Day 2
... Once the star is close to hydrostatic equilibrium, the contraction slows down. However, the star must continue to contract until the temperature in the core is high enough that nuclear fusion can begin and support the star! During the contraction the star's temperature stays about the same, but its ...
... Once the star is close to hydrostatic equilibrium, the contraction slows down. However, the star must continue to contract until the temperature in the core is high enough that nuclear fusion can begin and support the star! During the contraction the star's temperature stays about the same, but its ...
Lecture 19 - Stellar Lifecycles
... Low Mass Stars • Stars that are more massive than the Sun have stronger gravitational forces. • These forces need to be balanced by higher internal pressures. • These higher pressures result in higher temperatures which drive a higher rate of fusion reactions. A star like our Sun will remain • The H ...
... Low Mass Stars • Stars that are more massive than the Sun have stronger gravitational forces. • These forces need to be balanced by higher internal pressures. • These higher pressures result in higher temperatures which drive a higher rate of fusion reactions. A star like our Sun will remain • The H ...
What is a Star?
... a. absolute magnitude: actual brightness of a star (like absolute values in math) b. apparent magnitude: how bright a star appears based on its energy output, distance from you, & comparison to other stars ...
... a. absolute magnitude: actual brightness of a star (like absolute values in math) b. apparent magnitude: how bright a star appears based on its energy output, distance from you, & comparison to other stars ...
The Constellations
... Pattern in the Sky • Star pattern repeats itself about every 24 hours… because of the rotation of Earth with respect to the distant stars! • Star pattern in the winter is different from that in the summer… because of the revolution of Earth around the Sun! • Stars do move back a nd forth (a teeny-ti ...
... Pattern in the Sky • Star pattern repeats itself about every 24 hours… because of the rotation of Earth with respect to the distant stars! • Star pattern in the winter is different from that in the summer… because of the revolution of Earth around the Sun! • Stars do move back a nd forth (a teeny-ti ...
Neutron Stars
... Clicker Question: Which of the following is true about a binary pulsar system? A: It will last forever. B: They can only be found in star forming regions C: The total mass of the two pulsars must be more than 10 solar masses. D: Each of the pulsars was produced by a massive star that exploded in a ...
... Clicker Question: Which of the following is true about a binary pulsar system? A: It will last forever. B: They can only be found in star forming regions C: The total mass of the two pulsars must be more than 10 solar masses. D: Each of the pulsars was produced by a massive star that exploded in a ...
Observational astronomy
Observational astronomy is a division of the astronomical science that is concerned with recording data, in contrast with theoretical astrophysics, which is mainly concerned with finding out the measurable implications of physical models. It is the practice of observing celestial objects by using telescopes and other astronomical apparatus.As a science, the study of astronomy is somewhat hindered in that direct experiments with the properties of the distant universe are not possible. However, this is partly compensated by the fact that astronomers have a vast number of visible examples of stellar phenomena that can be examined. This allows for observational data to be plotted on graphs, and general trends recorded. Nearby examples of specific phenomena, such as variable stars, can then be used to infer the behavior of more distant representatives. Those distant yardsticks can then be employed to measure other phenomena in that neighborhood, including the distance to a galaxy.Galileo Galilei turned a telescope to the heavens and recorded what he saw. Since that time, observational astronomy has made steady advances with each improvement in telescope technology.A traditional division of observational astronomy is given by the region of the electromagnetic spectrum observed: Optical astronomy is the part of astronomy that uses optical components (mirrors, lenses and solid-state detectors) to observe light from near infrared to near ultraviolet wavelengths. Visible-light astronomy (using wavelengths that can be detected with the eyes, about 400 - 700 nm) falls in the middle of this range. Infrared astronomy deals with the detection and analysis of infrared radiation (this typically refers to wavelengths longer than the detection limit of silicon solid-state detectors, about 1 μm wavelength). The most common tool is the reflecting telescope but with a detector sensitive to infrared wavelengths. Space telescopes are used at certain wavelengths where the atmosphere is opaque, or to eliminate noise (thermal radiation from the atmosphere). Radio astronomy detects radiation of millimetre to dekametre wavelength. The receivers are similar to those used in radio broadcast transmission but much more sensitive. See also Radio telescopes. High-energy astronomy includes X-ray astronomy, gamma-ray astronomy, and extreme UV astronomy, as well as studies of neutrinos and cosmic rays.Optical and radio astronomy can be performed with ground-based observatories, because the atmosphere is relatively transparent at the wavelengths being detected. Observatories are usually located at high altitudes so as to minimise the absorption and distortion caused by the Earth's atmosphere. Some wavelengths of infrared light are heavily absorbed by water vapor, so many infrared observatories are located in dry places at high altitude, or in space.The atmosphere is opaque at the wavelengths used by X-ray astronomy, gamma-ray astronomy, UV astronomy and (except for a few wavelength ""windows"") far infrared astronomy, so observations must be carried out mostly from balloons or space observatories. Powerful gamma rays can, however be detected by the large air showers they produce, and the study of cosmic rays is a rapidly expanding branch of astronomy.For much of the history of observational astronomy, almost all observation was performed in the visual spectrum with optical telescopes. While the Earth's atmosphere is relatively transparent in this portion of the electromagnetic spectrum, most telescope work is still dependent on seeing conditions and air transparency, and is generally restricted to the night time. The seeing conditions depend on the turbulence and thermal variations in the air. Locations that are frequently cloudy or suffer from atmospheric turbulence limit the resolution of observations. Likewise the presence of the full Moon can brighten up the sky with scattered light, hindering observation of faint objects.For observation purposes, the optimal location for an optical telescope is undoubtedly in outer space. There the telescope can make observations without being affected by the atmosphere. However, at present it remains costly to lift telescopes into orbit. Thus the next best locations are certain mountain peaks that have a high number of cloudless days and generally possess good atmospheric conditions (with good seeing conditions). The peaks of the islands of Mauna Kea, Hawaii and La Palma possess these properties, as to a lesser extent do inland sites such as Llano de Chajnantor, Paranal, Cerro Tololo and La Silla in Chile. These observatory locations have attracted an assemblage of powerful telescopes, totalling many billion US dollars of investment.The darkness of the night sky is an important factor in optical astronomy. With the size of cities and human populated areas ever expanding, the amount of artificial light at night has also increased. These artificial lights produce a diffuse background illumination that makes observation of faint astronomical features very difficult without special filters. In a few locations such as the state of Arizona and in the United Kingdom, this has led to campaigns for the reduction of light pollution. The use of hoods around street lights not only improves the amount of light directed toward the ground, but also helps reduce the light directed toward the sky.Atmospheric effects (astronomical seeing) can severely hinder the resolution of a telescope. Without some means of correcting for the blurring effect of the shifting atmosphere, telescopes larger than about 15–20 cm in aperture can not achieve their theoretical resolution at visible wavelengths. As a result, the primary benefit of using very large telescopes has been the improved light-gathering capability, allowing very faint magnitudes to be observed. However the resolution handicap has begun to be overcome by adaptive optics, speckle imaging and interferometric imaging, as well as the use of space telescopes.Astronomers have a number of observational tools that they can use to make measurements of the heavens. For objects that are relatively close to the Sun and Earth, direct and very precise position measurements can be made against a more distant (and thereby nearly stationary) background. Early observations of this nature were used to develop very precise orbital models of the various planets, and to determine their respective masses and gravitational perturbations. Such measurements led to the discovery of the planets Uranus, Neptune, and (indirectly) Pluto. They also resulted in an erroneous assumption of a fictional planet Vulcan within the orbit of Mercury (but the explanation of the precession of Mercury's orbit by Einstein is considered one of the triumphs of his general relativity theory).