Chapter 2 History
... The fixed stars were supposed to move with the eighth sphere, and beyond that was heaven, the ninth immovable sphere. Aristotle identified this sphere as the prime mover, responsible for initiating the motion of all the other spheres, down to all things that move on earth. Thomas Aquinas identified the ...
... The fixed stars were supposed to move with the eighth sphere, and beyond that was heaven, the ninth immovable sphere. Aristotle identified this sphere as the prime mover, responsible for initiating the motion of all the other spheres, down to all things that move on earth. Thomas Aquinas identified the ...
at A-stars?
... Masses are much harder than distance, luminosity, or temperature • Since we are only ever seeing a point source, it is hard to determine how much mass is contained. – If we could see another nearby object (another star maybe?) we could use the gravity between the objects as a measure of the mass. ...
... Masses are much harder than distance, luminosity, or temperature • Since we are only ever seeing a point source, it is hard to determine how much mass is contained. – If we could see another nearby object (another star maybe?) we could use the gravity between the objects as a measure of the mass. ...
Wednesday, Sept. 24 - Department of Physics and Astronomy
... • mathematically defined colour space (CIE) of colour perception. • λ associated for colours perceived by humans (on the outer edge of the shape). ...
... • mathematically defined colour space (CIE) of colour perception. • λ associated for colours perceived by humans (on the outer edge of the shape). ...
Lecture 25&26
... Then the center of the Sun would go dark - “there’s a little dark spot on the Sun today.” The dark circle would expand toward the bright edge of the Sun and, 2 seconds later, all would be dark The 2 second delay happens because the center of the Sun is closer to us than the edges by about 2 ...
... Then the center of the Sun would go dark - “there’s a little dark spot on the Sun today.” The dark circle would expand toward the bright edge of the Sun and, 2 seconds later, all would be dark The 2 second delay happens because the center of the Sun is closer to us than the edges by about 2 ...
PowerPoint - Chandra X
... Chandra Science Highlights IC 443: A Supernova Remnant with a Newly Discovered Neutron Star 5,000 light years from Earth This Chandra image shows a point-like source of X-rays inside a cloud of high energy particles which is embedded in the supernova remnant IC443. Using this image, along with radio ...
... Chandra Science Highlights IC 443: A Supernova Remnant with a Newly Discovered Neutron Star 5,000 light years from Earth This Chandra image shows a point-like source of X-rays inside a cloud of high energy particles which is embedded in the supernova remnant IC443. Using this image, along with radio ...
The Doppler Shift (PowerPoint)
... look for displacements in the absorption lines. Measuring those displacements gives us the velocities of the stars relative to us. Note that one measurement only is required to figure out the instantaneous velocity – there’s no need to “do it again later and look for changes.” Note also that this do ...
... look for displacements in the absorption lines. Measuring those displacements gives us the velocities of the stars relative to us. Note that one measurement only is required to figure out the instantaneous velocity – there’s no need to “do it again later and look for changes.” Note also that this do ...
Lecture 7: The Sun - Department of Physics and Astronomy
... A theory may turn out to be a useful approximation, example: Newton’s laws are an approximation: they are superseded by Einstein’s theory of relativity on large scales and quantum mechanics on small scales. However, these laws are extremely useful as long as we know when and where they can be appl ...
... A theory may turn out to be a useful approximation, example: Newton’s laws are an approximation: they are superseded by Einstein’s theory of relativity on large scales and quantum mechanics on small scales. However, these laws are extremely useful as long as we know when and where they can be appl ...
UCSD Students` Presentation on Star Formation
... -After 10 million years, the protostar evolves into a true star. -Stage 6 = The radius of the star will be larger than an avg. sun, but b/c it has a lower surface temperature which means that its luminosity is only about 2/3 of its actual solar value. -What occurs in Stage 6? Protons begin fusing in ...
... -After 10 million years, the protostar evolves into a true star. -Stage 6 = The radius of the star will be larger than an avg. sun, but b/c it has a lower surface temperature which means that its luminosity is only about 2/3 of its actual solar value. -What occurs in Stage 6? Protons begin fusing in ...
Can we detect asteroid impacts with rocky extrasolar planets?
... developed that will look at large would give scientist areas of the sky for transient a better idea of astrophysical events. For example, whether our solar system was typical. NASA’s Swift spacecraft recently In particular it detected a giant stellar flare some would be an indicator of the 135 light ...
... developed that will look at large would give scientist areas of the sky for transient a better idea of astrophysical events. For example, whether our solar system was typical. NASA’s Swift spacecraft recently In particular it detected a giant stellar flare some would be an indicator of the 135 light ...
Sample pages 1 PDF
... However, he could not explain this possible relationship. Was it that of cause and effect between the two, or was there something else involved that “… gave origin to both the change of weather and the meteors?” (Olmsted 1834a, p. 402). The meteors were at their most striking in frequency and brilli ...
... However, he could not explain this possible relationship. Was it that of cause and effect between the two, or was there something else involved that “… gave origin to both the change of weather and the meteors?” (Olmsted 1834a, p. 402). The meteors were at their most striking in frequency and brilli ...
ph507lecnote06
... - Periodic oscillations of spectral lines (due to Doppler shift) - In some cases only one spectrum seen SPECTRUM BINARY: 2 sets of lines but no apparent orbital motion but spectrum is clearly combined from stars of differing spectral class. ECLIPSING BINARY: - Unresolved - Stars are orbiting in plan ...
... - Periodic oscillations of spectral lines (due to Doppler shift) - In some cases only one spectrum seen SPECTRUM BINARY: 2 sets of lines but no apparent orbital motion but spectrum is clearly combined from stars of differing spectral class. ECLIPSING BINARY: - Unresolved - Stars are orbiting in plan ...
Inverse Square Law
... If you think about this expression for a minute you will see that it makes sense. If both stars appear equally bright as seen from Earth, then the more distant star is the brighter one. Now to change a brightness ratio bA / bB or a luminosity ratio LA / LB to a magnitude difference we can use Table ...
... If you think about this expression for a minute you will see that it makes sense. If both stars appear equally bright as seen from Earth, then the more distant star is the brighter one. Now to change a brightness ratio bA / bB or a luminosity ratio LA / LB to a magnitude difference we can use Table ...
Brightness Luminosity and Inverse Square Law
... Sun as viewed from Earth is 1362 W/m2 We also know that Saturn is 9.7 times further away from our Sun than the Earth. If b α 1/d2 , then as viewed from Saturn, the sun would appear 1/(9.7)2 or 1/94th as bright. The brightness would then be 1362 W/m2(1/94) = 14.5 W/m2 ...
... Sun as viewed from Earth is 1362 W/m2 We also know that Saturn is 9.7 times further away from our Sun than the Earth. If b α 1/d2 , then as viewed from Saturn, the sun would appear 1/(9.7)2 or 1/94th as bright. The brightness would then be 1362 W/m2(1/94) = 14.5 W/m2 ...
The kinematics of Galaxies in Compact Groups
... the galaxies do not correlate with any galaxy/group parameter. 2) Rubin et al. (1991) studied 32 galaxies – found that 2/3 have peculiar rotation curves. They found a large offset of the TF relation with respect to the field relation in the sense that galaxies in compact groups have “too low velocit ...
... the galaxies do not correlate with any galaxy/group parameter. 2) Rubin et al. (1991) studied 32 galaxies – found that 2/3 have peculiar rotation curves. They found a large offset of the TF relation with respect to the field relation in the sense that galaxies in compact groups have “too low velocit ...
In This Issue… The Milky Way above Kancamagus Highway
... Manning the NHAS booth at Market Square Day were Tom Cocchiaro, Gardner Gerry, Dave Speltz and Paul Winalski. We had two refractors for white light solar observing, plus a double-stacked Lunt and a PST for H-alpha. It was overcast and drizzly at first, so the white light scopes were focused on the c ...
... Manning the NHAS booth at Market Square Day were Tom Cocchiaro, Gardner Gerry, Dave Speltz and Paul Winalski. We had two refractors for white light solar observing, plus a double-stacked Lunt and a PST for H-alpha. It was overcast and drizzly at first, so the white light scopes were focused on the c ...
The Relationship Between Preservice Science Teachers` Attitude
... science deteriorate as students become older, but Reid and Skryabina (2002) did not find such a deterioration. Most studies have focused on only one or two of the variables that can affect attitudes (Gardner, 1995). Variables examined in previous research have included the attitude instrument itself ...
... science deteriorate as students become older, but Reid and Skryabina (2002) did not find such a deterioration. Most studies have focused on only one or two of the variables that can affect attitudes (Gardner, 1995). Variables examined in previous research have included the attitude instrument itself ...
Astronomy Rough Notes
... Milky Way galaxy (our galaxy), the Andromeda Galaxy (nearest big neighbor galaxy to the Milky Way. Define Astronomical Unit. Know its abbreviation. Define light-year. Know its abbreviation. Identify objects that are about a m in size, a cm in size, a mm in size. Estimate sizes of various objects usi ...
... Milky Way galaxy (our galaxy), the Andromeda Galaxy (nearest big neighbor galaxy to the Milky Way. Define Astronomical Unit. Know its abbreviation. Define light-year. Know its abbreviation. Identify objects that are about a m in size, a cm in size, a mm in size. Estimate sizes of various objects usi ...
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).