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... * A long time ago, astronomers thought that the Earth was the centre of the Universe. This was called the geocentric model. The evidence for this model came from observations of the sky using the naked eye. After the telescope was invented, astronomers quickly gathered evidence which showed that the ...
... * A long time ago, astronomers thought that the Earth was the centre of the Universe. This was called the geocentric model. The evidence for this model came from observations of the sky using the naked eye. After the telescope was invented, astronomers quickly gathered evidence which showed that the ...
Measuring Distance in the Universe
... second. So we're talking really slight, tiny changes. But these are changes that we can measure and if you get outside of the earth's atmosphere, you can actually measure the more precise changes. A satellite called Hipparcos measured the slight motions of stars and it had an accuracy of about 1 mil ...
... second. So we're talking really slight, tiny changes. But these are changes that we can measure and if you get outside of the earth's atmosphere, you can actually measure the more precise changes. A satellite called Hipparcos measured the slight motions of stars and it had an accuracy of about 1 mil ...
Galaxies * Island universes
... • Mass infall is high when galaxy is young, so bright accretion disk can overwhelm the light from the rest of the galaxy and a Quasar may even result. Up to 1 solar mass/year infall. • Later, as the galaxy ages, the stuff that CAN fall in, pretty much HAS fallen in, and fueling rate drops. The core ...
... • Mass infall is high when galaxy is young, so bright accretion disk can overwhelm the light from the rest of the galaxy and a Quasar may even result. Up to 1 solar mass/year infall. • Later, as the galaxy ages, the stuff that CAN fall in, pretty much HAS fallen in, and fueling rate drops. The core ...
Penentuan Jarak dalam Astronomi II
... SN 1604 (Kepler’s supernova Ia in the Ophiuchus constellation) achieved -2.5m As expected, we could have miss a number of Supernovae events that have been exploded deep inside the galactic disc full of dense and opaque interstellar dust ...
... SN 1604 (Kepler’s supernova Ia in the Ophiuchus constellation) achieved -2.5m As expected, we could have miss a number of Supernovae events that have been exploded deep inside the galactic disc full of dense and opaque interstellar dust ...
The Milky Way - The Independent School
... …etc., we find that most of the mass is “invisible”! • The nature of this “dark matter” is not understood at this time. • Some ideas: brown dwarfs, small black holes, exotic elementary particles. ...
... …etc., we find that most of the mass is “invisible”! • The nature of this “dark matter” is not understood at this time. • Some ideas: brown dwarfs, small black holes, exotic elementary particles. ...
M101: The Pinwheel Galaxy
... Major (The Great Bear). We are seeing M101 as it looked 25 million years ago.The light we are seeing from the galaxy began its journey to Earth at the beginning of our planet’s Miocene Period, when mammals flourished and the Mastodon first appeared. ...
... Major (The Great Bear). We are seeing M101 as it looked 25 million years ago.The light we are seeing from the galaxy began its journey to Earth at the beginning of our planet’s Miocene Period, when mammals flourished and the Mastodon first appeared. ...
dark matter - University of Texas Astronomy Home Page
... apply it to our solar system, and galaxies on a whole. Fact about orbital motion: ...
... apply it to our solar system, and galaxies on a whole. Fact about orbital motion: ...
Edwin Hubble (1889
... telescopes. Yet, he wrote, "Extremely little is known of the nature of nebulae, and no significant classification has yet been suggested; not even a precise definition has been formulated." The way Hubble discovered to classify nebulae is described here. After serving in World War I, Hubble joined t ...
... telescopes. Yet, he wrote, "Extremely little is known of the nature of nebulae, and no significant classification has yet been suggested; not even a precise definition has been formulated." The way Hubble discovered to classify nebulae is described here. After serving in World War I, Hubble joined t ...
ACTIVE GALAXIES
... either side of the galaxy • Radio source sizes often 300 kpc or more --- much bigger than their host galaxies. • Head-tail radio galaxies arise when jets are bent by the ram-pressure of gas as the host galaxy moves through it. ...
... either side of the galaxy • Radio source sizes often 300 kpc or more --- much bigger than their host galaxies. • Head-tail radio galaxies arise when jets are bent by the ram-pressure of gas as the host galaxy moves through it. ...
MS 1512–CB58 - Columbia University Department of Astronomy
... – quite possibly in cB58 we are witnessing the formation of a galactic bulge or an elliptical galaxy. The results of our chemical analysis are consistent with the scenario proposed by Shapley et al. (2001), whereby galaxies whose UV spectra are dominated by strong, blueshifted, absorption lines, as ...
... – quite possibly in cB58 we are witnessing the formation of a galactic bulge or an elliptical galaxy. The results of our chemical analysis are consistent with the scenario proposed by Shapley et al. (2001), whereby galaxies whose UV spectra are dominated by strong, blueshifted, absorption lines, as ...
Hoag`s Object
... In the initial announcement of his discovery, Art Hoag proposed the hypothesis that the visible ring was a product of gravitational lensing. This idea was later discarded because the nucleus and the ring have the same redshift, and because more advanced telescopes revealed the knotty structure of th ...
... In the initial announcement of his discovery, Art Hoag proposed the hypothesis that the visible ring was a product of gravitational lensing. This idea was later discarded because the nucleus and the ring have the same redshift, and because more advanced telescopes revealed the knotty structure of th ...
the text the talk here
... the fixed stars. Nothing exists outside this sphere. Needless to say, this was an assumption, not based on any observation or calculation. Between the outer sphere and the Moon’s orbit there is an intermediate region occupied by the Sun and planets. The inner region had the Earth at the centre with ...
... the fixed stars. Nothing exists outside this sphere. Needless to say, this was an assumption, not based on any observation or calculation. Between the outer sphere and the Moon’s orbit there is an intermediate region occupied by the Sun and planets. The inner region had the Earth at the centre with ...
APOD 2016 Calendar
... foreground landscape of Doi Inthanon National Park in Thailand, as well as the numerous stars glowing across a dark background starscape. Also visible are the planet Venus and a band of zodiacal light on the image left. Unusual events are also captured, however. First, the central band of our Milky ...
... foreground landscape of Doi Inthanon National Park in Thailand, as well as the numerous stars glowing across a dark background starscape. Also visible are the planet Venus and a band of zodiacal light on the image left. Unusual events are also captured, however. First, the central band of our Milky ...
Active Galactic Nuclei: are they important?
... The same trend should be seen in radio-quiet sources. We think we have recently found a way to detect it observationally. In a collection of 100 000 quasars from SDSS we have found one with strong LILs and weak HIL., and no NLR. ...
... The same trend should be seen in radio-quiet sources. We think we have recently found a way to detect it observationally. In a collection of 100 000 quasars from SDSS we have found one with strong LILs and weak HIL., and no NLR. ...
exam 3 review lecture
... – Big bang, expansion, Hubble Law – Structure of universe, CMB, how did matter form? – Fate of universe ...
... – Big bang, expansion, Hubble Law – Structure of universe, CMB, how did matter form? – Fate of universe ...
Early Star-Forming Galaxies
... Rodighiero used Herschel ’s far-infrared camera to look for galaxies hidden from visible-light observations because of their intervening dust. This allowed the astronomers to assemble a more complete picture of star birth than ever before. The team targeted two well-known regions of the sky that ha ...
... Rodighiero used Herschel ’s far-infrared camera to look for galaxies hidden from visible-light observations because of their intervening dust. This allowed the astronomers to assemble a more complete picture of star birth than ever before. The team targeted two well-known regions of the sky that ha ...
Galaxy alignment within dark matter halos
... Directly compared with observational results This is the first attempt to use gas simulations to directly studying the satellite-central galaxy alignment. Reference: Dong, X.C., Lin, W.P., et al., 2014, ApJ Letter, ...
... Directly compared with observational results This is the first attempt to use gas simulations to directly studying the satellite-central galaxy alignment. Reference: Dong, X.C., Lin, W.P., et al., 2014, ApJ Letter, ...
Slide 1
... No. For K and M stars to account for the mass, they would have to be more common than we have seen with the HST. Brown dwarfs would have to be even more common. Interstellar dust and gas? No and no. While often difficult to detect in visible wavelengths, these are not hidden from resourceful astrono ...
... No. For K and M stars to account for the mass, they would have to be more common than we have seen with the HST. Brown dwarfs would have to be even more common. Interstellar dust and gas? No and no. While often difficult to detect in visible wavelengths, these are not hidden from resourceful astrono ...
Dear Teachers - Jeffrey Bennett
... Scale Activity 2: The Solar System Before you begin: • Find a ball or piece of fruit (grapefruits work well) approximately 14 cm in diameter, to represent the Sun. • (optional) You can use clay or a set of ball bearings to use as models for the planets. • You will need a ruler and tape measure. • Y ...
... Scale Activity 2: The Solar System Before you begin: • Find a ball or piece of fruit (grapefruits work well) approximately 14 cm in diameter, to represent the Sun. • (optional) You can use clay or a set of ball bearings to use as models for the planets. • You will need a ruler and tape measure. • Y ...
Practical cosmology with the Local Volume galaxies
... peculiar velocities within the Volume. A peculiar velocity map for the LV galaxies in the LG reference frame shows the local Hubble flow to be generally calm with peculiar velocity variations within ± 30 km/s. There is only a small area of negative peculiar velocities about - 250 km/s in direction t ...
... peculiar velocities within the Volume. A peculiar velocity map for the LV galaxies in the LG reference frame shows the local Hubble flow to be generally calm with peculiar velocity variations within ± 30 km/s. There is only a small area of negative peculiar velocities about - 250 km/s in direction t ...
Astrophysics Questions (DRAFT)
... 73. What is a \millisecond pulsar"? What is the shortest spin period known for such an object? Estimate a lower bound to its mean density. 74. What is the \Shapiro time delay"? 75. Derive a plausible relation between the luminosity of an X-ray pulsar and its spin-up rate. 76. What are the \anomalous ...
... 73. What is a \millisecond pulsar"? What is the shortest spin period known for such an object? Estimate a lower bound to its mean density. 74. What is the \Shapiro time delay"? 75. Derive a plausible relation between the luminosity of an X-ray pulsar and its spin-up rate. 76. What are the \anomalous ...
It is now recognized that the vast majority of ellipticals are of
... Triaxiality is also supported by observations of isophotal twists in some galaxies (would not see these if oblate or prolate) It was once thought that the shape of ellipticals varied from spherical to highly elongated. The Hubble classification of elliptical galaxies ranges from E0 for those that ar ...
... Triaxiality is also supported by observations of isophotal twists in some galaxies (would not see these if oblate or prolate) It was once thought that the shape of ellipticals varied from spherical to highly elongated. The Hubble classification of elliptical galaxies ranges from E0 for those that ar ...
... change? Well, this increase is primarily due to the humanmade greenhouse gases. Levels of CO2 have increased from around 280 parts per million (ppm) to around 380 ppm now. Studies of ice core show that concentrations of CO2 have not been so high for nearly half a million years. At the current rate o ...
Observable universe
The observable universe consists of the galaxies and other matter that can, in principle, be observed from Earth at the present time because light and other signals from these objects has had time to reach the Earth since the beginning of the cosmological expansion. Assuming the universe is isotropic, the distance to the edge of the observable universe is roughly the same in every direction. That is, the observable universe is a spherical volume (a ball) centered on the observer. Every location in the Universe has its own observable universe, which may or may not overlap with the one centered on Earth.The word observable used in this sense does not depend on whether modern technology actually permits detection of radiation from an object in this region (or indeed on whether there is any radiation to detect). It simply indicates that it is possible in principle for light or other signals from the object to reach an observer on Earth. In practice, we can see light only from as far back as the time of photon decoupling in the recombination epoch. That is when particles were first able to emit photons that were not quickly re-absorbed by other particles. Before then, the Universe was filled with a plasma that was opaque to photons.The surface of last scattering is the collection of points in space at the exact distance that photons from the time of photon decoupling just reach us today. These are the photons we detect today as cosmic microwave background radiation (CMBR). However, with future technology, it may be possible to observe the still older relic neutrino background, or even more distant events via gravitational waves (which also should move at the speed of light). Sometimes astrophysicists distinguish between the visible universe, which includes only signals emitted since recombination—and the observable universe, which includes signals since the beginning of the cosmological expansion (the Big Bang in traditional cosmology, the end of the inflationary epoch in modern cosmology). According to calculations, the comoving distance (current proper distance) to particles from the CMBR, which represent the radius of the visible universe, is about 14.0 billion parsecs (about 45.7 billion light years), while the comoving distance to the edge of the observable universe is about 14.3 billion parsecs (about 46.6 billion light years), about 2% larger.The best estimate of the age of the universe as of 2015 is 7010137990000000000♠13.799±0.021 billion years but due to the expansion of space humans are observing objects that were originally much closer but are now considerably farther away (as defined in terms of cosmological proper distance, which is equal to the comoving distance at the present time) than a static 13.8 billion light-years distance. It is estimated that the diameter of the observable universe is about 28 gigaparsecs (91 billion light-years, 8.8×1026 metres or 5.5×1023 miles), putting the edge of the observable universe at about 46–47 billion light-years away.