SPACETIME SINGULARITIES: The STORY of BLACK HOLES
... All of this is easy to say, but the attitude of most early workers in GR was to ignore the possible existence of singularities, and/or hope that they would just go away. The reaction of Einstein to the discovery of singular solutions to his equations was quite striking. In the period 1938-39, Oppenh ...
... All of this is easy to say, but the attitude of most early workers in GR was to ignore the possible existence of singularities, and/or hope that they would just go away. The reaction of Einstein to the discovery of singular solutions to his equations was quite striking. In the period 1938-39, Oppenh ...
The Formation and Evolution of Massive Black Holes - Ira-Inaf
... produce a very massive star of up to a few thousand M⊙ before the first supernovae explode. When heavy elements are still rare, just about when the second generation of stars occurs, the final fate of a very massive star is to collapse into a black hole with a mass similar to that of its progenitor. ...
... produce a very massive star of up to a few thousand M⊙ before the first supernovae explode. When heavy elements are still rare, just about when the second generation of stars occurs, the final fate of a very massive star is to collapse into a black hole with a mass similar to that of its progenitor. ...
Accretion Disks
... liberated in the boundary layer between disk and star • Accretion disk around a black hole – Inner edge often set by the “innermost stable circular orbit” (ISCO) – GR effects make circular orbits within the ISCO unstable… matter rapidly spirals in – Risco=6GM/c2 for a non-rotating black hole ...
... liberated in the boundary layer between disk and star • Accretion disk around a black hole – Inner edge often set by the “innermost stable circular orbit” (ISCO) – GR effects make circular orbits within the ISCO unstable… matter rapidly spirals in – Risco=6GM/c2 for a non-rotating black hole ...
Comparing stars - The Open University
... We have added to Figure 5 an indication of the colour associated with each temperature. However, to the unaided eye, star colours are in many cases not very striking. This is partly because too little light is being received for our colour vision to be strongly excited, and partly because the colour ...
... We have added to Figure 5 an indication of the colour associated with each temperature. However, to the unaided eye, star colours are in many cases not very striking. This is partly because too little light is being received for our colour vision to be strongly excited, and partly because the colour ...
A double detached shell around a post
... similar to a fried egg, and we dubbed it the “Fried Egg” nebula. The object is circular at large-scale and the central star can be observed in all filters. The most striking aspect of these images is the presence of a double detached shell around the central star. This is more clearly visible in Fig ...
... similar to a fried egg, and we dubbed it the “Fried Egg” nebula. The object is circular at large-scale and the central star can be observed in all filters. The most striking aspect of these images is the presence of a double detached shell around the central star. This is more clearly visible in Fig ...
File
... energy keeping the star from collapsing, so gravity start to takes over and try to compress the stars material into its core. But the star only collapses so far that the helium atoms can begin to combine into carbon atoms. This process now provides enough energy to stop the star from collapsing and ...
... energy keeping the star from collapsing, so gravity start to takes over and try to compress the stars material into its core. But the star only collapses so far that the helium atoms can begin to combine into carbon atoms. This process now provides enough energy to stop the star from collapsing and ...
copyright 2002 scientific american, inc.
... Earth’s atmosphere causes visible starlight to twinkle, interstellar plasma causes radio waves to scintillate. For this process to be visible, the source must be so small and far away that it appears to us as a mere point. Planets do not twinkle, because, being fairly nearby, they look like disks, n ...
... Earth’s atmosphere causes visible starlight to twinkle, interstellar plasma causes radio waves to scintillate. For this process to be visible, the source must be so small and far away that it appears to us as a mere point. Planets do not twinkle, because, being fairly nearby, they look like disks, n ...
The Gould Belt
... In recent decades x-ray data from the ROSAT 1 , Chandra 2 , and XMM-Newton 3 satellites, earthbound infrared photometric data from 2MASS [27], and the HIPPARCOS [28] and Tycho-2 [29] astronomical catalogs have been used. Torra, et al. [30], have analyzed the extensive HIPPARCOS sample of stars in sp ...
... In recent decades x-ray data from the ROSAT 1 , Chandra 2 , and XMM-Newton 3 satellites, earthbound infrared photometric data from 2MASS [27], and the HIPPARCOS [28] and Tycho-2 [29] astronomical catalogs have been used. Torra, et al. [30], have analyzed the extensive HIPPARCOS sample of stars in sp ...
Volume 11, Number 4 - RASC NB - Royal Astronomical Society of
... He reported on the progress of the “Tour of the Messiers” he & some of the group are following. It can be difficult to get out there when life is busy, but especially when the weather doesn’t cooperate. Doggone clouds & rain. Curt gave the “What’s Up” for April. There have been a few sunspots & a fe ...
... He reported on the progress of the “Tour of the Messiers” he & some of the group are following. It can be difficult to get out there when life is busy, but especially when the weather doesn’t cooperate. Doggone clouds & rain. Curt gave the “What’s Up” for April. There have been a few sunspots & a fe ...
Two distinct sequences of blue straggler stars in the globular cluster
... Creek ACT 2611, Australia Stars in globular clusters are generally believed to have all formed at the same time, early in the Galaxy's history1. 'Blue stragglers' are stars sufficiently massive2 that they should have evolved into white dwarfs long ago. Two possible mechanisms have been proposed for ...
... Creek ACT 2611, Australia Stars in globular clusters are generally believed to have all formed at the same time, early in the Galaxy's history1. 'Blue stragglers' are stars sufficiently massive2 that they should have evolved into white dwarfs long ago. Two possible mechanisms have been proposed for ...
Winds of Main-Sequence Stars - Harvard
... (GHRS, FUSE, high-spectral-res ground-based) led to better stellar wind ...
... (GHRS, FUSE, high-spectral-res ground-based) led to better stellar wind ...
The distribution of the ISM in the Milky Way A three
... of sight passing both through dense environments (e.g., the Galactic center) and through areas almost free of dust and gas (e.g., the Galactic poles). The way that dust and gas (both in molecular and neutral phases) are distributed inside the Galaxy not only shapes the appearance of the Galaxy in di ...
... of sight passing both through dense environments (e.g., the Galactic center) and through areas almost free of dust and gas (e.g., the Galactic poles). The way that dust and gas (both in molecular and neutral phases) are distributed inside the Galaxy not only shapes the appearance of the Galaxy in di ...
Galaxy / Cluster Ecosystem Ming Sun (University of Alabama in Huntsville)
... Sun + 2007 Later more embedded coronae discovered (Yamasaki+2002; Sun+2002, 2005, 2006) and the first sample in Sun+2007 ...
... Sun + 2007 Later more embedded coronae discovered (Yamasaki+2002; Sun+2002, 2005, 2006) and the first sample in Sun+2007 ...
Dust in the Reionization Era: ALMA Observations of a z =8.38
... Dust in the reionization era: ALMA observations of a z=8.38 Galaxy of dust, presumably from early supernovae in the first few 100 Myr since reionization began. The key measures are the dust and stellar masses and the likely average past star formation rate. We first estimate some physical propertie ...
... Dust in the reionization era: ALMA observations of a z=8.38 Galaxy of dust, presumably from early supernovae in the first few 100 Myr since reionization began. The key measures are the dust and stellar masses and the likely average past star formation rate. We first estimate some physical propertie ...
1-structure-of-the-universe-and-the-big-bang
... A) red shift in the light from distant galaxies B) change in the swing direction of a Foucault pendulum on Earth C) parallelism of Earth's axis in orbit D) spiral shape of the Milky Way Galaxy 16. According to the big bang theory, the universe began as an explosion and is still expanding. This theor ...
... A) red shift in the light from distant galaxies B) change in the swing direction of a Foucault pendulum on Earth C) parallelism of Earth's axis in orbit D) spiral shape of the Milky Way Galaxy 16. According to the big bang theory, the universe began as an explosion and is still expanding. This theor ...
z= 1000 - z= 10
... •Metals usually dominate the cooling --- but there are no metals •Molecular hydrogen is the only significant cooling in primordial gas •Molecular hydrogen usually forms on dust…but there is no dust ...
... •Metals usually dominate the cooling --- but there are no metals •Molecular hydrogen is the only significant cooling in primordial gas •Molecular hydrogen usually forms on dust…but there is no dust ...
The Case against Copernicus
... two major advantages going for it: it squared with deep intuitions about how the world appeared to behave, and it fit the available data better than Copernicus’s system did. Brahe was a towering figure. He ran a huge research program with a castlelike observatory, a NASA-like budget, and the finest ...
... two major advantages going for it: it squared with deep intuitions about how the world appeared to behave, and it fit the available data better than Copernicus’s system did. Brahe was a towering figure. He ran a huge research program with a castlelike observatory, a NASA-like budget, and the finest ...
Time From the Perspective of a Particle Physicist
... Spiral: rotation/gas/dust and active star formation, and irregulars active star formation but indistinct shape. Galaxies are moving away from us with v=Hd v=velocity, d=distance, and H=Hubble constant. Milky Way has inner nucleus, spiral arms (active star formation, halo of old stars (early shape) C ...
... Spiral: rotation/gas/dust and active star formation, and irregulars active star formation but indistinct shape. Galaxies are moving away from us with v=Hd v=velocity, d=distance, and H=Hubble constant. Milky Way has inner nucleus, spiral arms (active star formation, halo of old stars (early shape) C ...
Peak Bagging of red giant stars observed by Kepler: first results with
... also for the study of RGs in open clusters (e.g. [25,7]). The discovery of so-called mixed modes [1] has led to a significant improvement in our understanding of the internal structure and evolution of RGs. In particular, the characteristic spacing in period of mixed modes frequencies provides a dire ...
... also for the study of RGs in open clusters (e.g. [25,7]). The discovery of so-called mixed modes [1] has led to a significant improvement in our understanding of the internal structure and evolution of RGs. In particular, the characteristic spacing in period of mixed modes frequencies provides a dire ...
Star formation
Star formation is the process by which dense regions within molecular clouds in interstellar space, sometimes referred to as ""stellar nurseries"" or ""star-forming regions"", collapse to form stars. As a branch of astronomy, star formation includes the study of the interstellar medium (ISM) and giant molecular clouds (GMC) as precursors to the star formation process, and the study of protostars and young stellar objects as its immediate products. It is closely related to planet formation, another branch of astronomy. Star formation theory, as well as accounting for the formation of a single star, must also account for the statistics of binary stars and the initial mass function.In June 2015, astronomers reported evidence for Population III stars in the Cosmos Redshift 7 galaxy at z = 6.60. Such stars are likely to have existed in the very early universe (i.e., at high redshift), and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life as we know it.