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ASTR 2020 Space Astronomy Homework #3 Due Tuesday, 4
... 3] Parallax. As we discussed in class, the unit called a parsec is defined as the distance at which the Earth-Sun mean separation (the Astronomical Unit), subtends 1 arc-second (assuming that the Earth-Sun separation is at right angles to the line connecting the Sun to the distant object). [a] How ...
... 3] Parallax. As we discussed in class, the unit called a parsec is defined as the distance at which the Earth-Sun mean separation (the Astronomical Unit), subtends 1 arc-second (assuming that the Earth-Sun separation is at right angles to the line connecting the Sun to the distant object). [a] How ...
Answers
... His calculations treated light as if it was made of particles with mass that would slow down and return if they weren’t moving fast enough. His answer just happens to be the same answer that you get from GR, and this is only true if the black hole is not rotating. (Newton’s laws of gravity also pred ...
... His calculations treated light as if it was made of particles with mass that would slow down and return if they weren’t moving fast enough. His answer just happens to be the same answer that you get from GR, and this is only true if the black hole is not rotating. (Newton’s laws of gravity also pred ...
Supernovas Neutron Stars and Black Holes
... The limiting mass for the core remnant to form a black hole rather than a neutron star is around 2 solar masses. ...
... The limiting mass for the core remnant to form a black hole rather than a neutron star is around 2 solar masses. ...
KERR (SPINNING) BLACK HOLES Generalized BH solution that includes spin Roy Kerr
... The Ergosphere: region inside which space rotates so fast that is is impossible for a body to hover in such a way to appear stationary to a distant observer. [Image from “Gavity’s Fatal Attraction” by Begelman & Rees] ...
... The Ergosphere: region inside which space rotates so fast that is is impossible for a body to hover in such a way to appear stationary to a distant observer. [Image from “Gavity’s Fatal Attraction” by Begelman & Rees] ...
Day 9 Lecture
... unpleasant side effects. You may wonder how does Bob head and feet communicate once inside of the horizon. Note that although a nerve signal may not climb any further distance from the singularity once within the horizon, Bob’s head continues plunging and meets the signal at a lower radius. Thus the ...
... unpleasant side effects. You may wonder how does Bob head and feet communicate once inside of the horizon. Note that although a nerve signal may not climb any further distance from the singularity once within the horizon, Bob’s head continues plunging and meets the signal at a lower radius. Thus the ...
BlackHoles
... See http://saturn.jpl.nasa.gov/news/press-releases-03/20031002-pr-a.cfm So if you cram enough mass into a small enough volume, than the gravitational well becomes so steep that not even light (moving at the speed of light) can climb out. That is a black hole. WHAT IS THE STRUCTURE OF A BLACK HOLE? ...
... See http://saturn.jpl.nasa.gov/news/press-releases-03/20031002-pr-a.cfm So if you cram enough mass into a small enough volume, than the gravitational well becomes so steep that not even light (moving at the speed of light) can climb out. That is a black hole. WHAT IS THE STRUCTURE OF A BLACK HOLE? ...
Black Holes
... event occurs within the boundary, information from that event cannot reach an outside observer, making it impossible to determine if such an event occurred. • To a distant observer, clocks near a black hole appear to tick more slowly than those further away from the black hole. Due to this effect, k ...
... event occurs within the boundary, information from that event cannot reach an outside observer, making it impossible to determine if such an event occurred. • To a distant observer, clocks near a black hole appear to tick more slowly than those further away from the black hole. Due to this effect, k ...
MIDTERM #2 THURSDAY APRIL 16, 2015 AST142 1. Black hole
... 1. Black hole Growth The number of quasars per unit volume peaks at a redshift of about 2. This time is thought to be the epoch of massive black hole growth. How long would it take a 106 M black hole accreting at its Eddington luminosity to increase to 109 M ? Assume the luminosity L = M˙ c2 wher ...
... 1. Black hole Growth The number of quasars per unit volume peaks at a redshift of about 2. This time is thought to be the epoch of massive black hole growth. How long would it take a 106 M black hole accreting at its Eddington luminosity to increase to 109 M ? Assume the luminosity L = M˙ c2 wher ...
Closing in on Black Holes
... • Pringle and Rees 1972 → quasi periodic oscillations at inner edge of accretion disc • So black hole found? or some other sort of star with an unexplained small source of X-rays? ...
... • Pringle and Rees 1972 → quasi periodic oscillations at inner edge of accretion disc • So black hole found? or some other sort of star with an unexplained small source of X-rays? ...
ASTR 220 Homework #7 Solutions
... From the diagrams, we can see that any pattern we begin with in the galaxy will be destroyed over time by the rotation of the galaxy. Since stars at different distances from the center of the galaxy have different orbital periods, no pattern can stay fixed. The stars in the outer part of the galaxy ...
... From the diagrams, we can see that any pattern we begin with in the galaxy will be destroyed over time by the rotation of the galaxy. Since stars at different distances from the center of the galaxy have different orbital periods, no pattern can stay fixed. The stars in the outer part of the galaxy ...
Relativistic jets in microquasars, AGN and GRBs
... GAMMA-RAY BURSTS OF SHORT DURATION Duration < 1 second Origin of GRBs of short duration: Double NS Mergers?--Still speculative ...
... GAMMA-RAY BURSTS OF SHORT DURATION Duration < 1 second Origin of GRBs of short duration: Double NS Mergers?--Still speculative ...
22_SN1987a
... • Formation of the iron core: nuclei lighter than iron give off energy when they are formed by fusion, nuclei heavier than iron absorb energy when they are formed by fusion. Iron is on the dividing line between these processes. ...
... • Formation of the iron core: nuclei lighter than iron give off energy when they are formed by fusion, nuclei heavier than iron absorb energy when they are formed by fusion. Iron is on the dividing line between these processes. ...
Document
... A probe nearing the event horizon of a black hole will be seen by observers as experiencing a dramatic redshift as it gets closer, so that time appears to be going more and more slowly as it approaches the event horizon. This is called a gravitational redshift—it is not due to motion, but to the lar ...
... A probe nearing the event horizon of a black hole will be seen by observers as experiencing a dramatic redshift as it gets closer, so that time appears to be going more and more slowly as it approaches the event horizon. This is called a gravitational redshift—it is not due to motion, but to the lar ...
Powerpoint Presentation (large file)
... • A rotating black hole (one with angular momentum) has an ergoregion around the outside of the event horizon • In the ergoregion, space and time themselves are dragged along with the rotation of the black hole ...
... • A rotating black hole (one with angular momentum) has an ergoregion around the outside of the event horizon • In the ergoregion, space and time themselves are dragged along with the rotation of the black hole ...
Energy and Mass - Cornell Astronomy
... Gravity is no longer described as a force, but as the curvature of “spacetime”. A spacecraft in orbit around the Earth tries to follow a “straight” path – however, space-time is curved and makes things fall toward the Earth! Space-time is curved and matter is the source of the curvature. Matter is a ...
... Gravity is no longer described as a force, but as the curvature of “spacetime”. A spacecraft in orbit around the Earth tries to follow a “straight” path – however, space-time is curved and makes things fall toward the Earth! Space-time is curved and matter is the source of the curvature. Matter is a ...
black hole
... length between ticks is infinite, wavelength is infinite, appears to stop (but we can’t see it anyway ...
... length between ticks is infinite, wavelength is infinite, appears to stop (but we can’t see it anyway ...
The Daily Sun 1st Sept
... astrophysical observations was also highlighted and supported by some videos. The key-note speaker dedicated his speech to late Professor Emeritus Jamal Nazrul Islam who was a renowned mathematical physicist, cosmologist and educationist. ...
... astrophysical observations was also highlighted and supported by some videos. The key-note speaker dedicated his speech to late Professor Emeritus Jamal Nazrul Islam who was a renowned mathematical physicist, cosmologist and educationist. ...
Chapter 2 Cosmic tombstones
... Neutron stars are compact objects supported by pressure of neutrons created in the process of a stellar collapse A typical neutron star has a ~10 km radius, a ~1.4 M mass, it spins several times a second and has a huge, frozen-in magnetic field A neutron star is formed, when a massive stellar core ...
... Neutron stars are compact objects supported by pressure of neutrons created in the process of a stellar collapse A typical neutron star has a ~10 km radius, a ~1.4 M mass, it spins several times a second and has a huge, frozen-in magnetic field A neutron star is formed, when a massive stellar core ...
escape velocity
... After some massive stars (greater than 10 suns) explode as supernovae, they will retain a mass of 2 to 3 solar masses in their cores • Nothing in the universe is strong enough to hold up the remaining mass against the force of gravity, so it collapses into a black hole • Matter that falls into a bla ...
... After some massive stars (greater than 10 suns) explode as supernovae, they will retain a mass of 2 to 3 solar masses in their cores • Nothing in the universe is strong enough to hold up the remaining mass against the force of gravity, so it collapses into a black hole • Matter that falls into a bla ...
Black Hole Detection - University of Dayton
... As the matter falls into the event horizon, it experiences strong accelerations. As this happens, they will radiate energy in the form of photons (recall the Aurora Borealis) ...
... As the matter falls into the event horizon, it experiences strong accelerations. As this happens, they will radiate energy in the form of photons (recall the Aurora Borealis) ...
Hawking radiation
![](https://commons.wikimedia.org/wiki/Special:FilePath/BH_LMC.png?width=300)
Hawking radiation is black body radiation that is predicted to be released by black holes, due to quantum effects near the event horizon. It is named after the physicist Stephen Hawking, who provided a theoretical argument for its existence in 1974, and sometimes also after Jacob Bekenstein, who predicted that black holes should have a finite, non-zero temperature and entropy.Hawking's work followed his visit to Moscow in 1973 where the Soviet scientists Yakov Zeldovich and Alexei Starobinsky showed him that, according to the quantum mechanical uncertainty principle, rotating black holes should create and emit particles. Hawking radiation reduces the mass and energy of black holes and is therefore also known as black hole evaporation. Because of this, black holes that lose more mass than they gain through other means are expected to shrink and ultimately vanish. Micro black holes are predicted to be larger net emitters of radiation than larger black holes and should shrink and dissipate faster.In September 2010, a signal that is closely related to black hole Hawking radiation (see analog gravity) was claimed to have been observed in a laboratory experiment involving optical light pulses. However, the results remain unverified and debatable. Other projects have been launched to look for this radiation within the framework of analog gravity. In June 2008, NASA launched the Fermi space telescope, which is searching for the terminal gamma-ray flashes expected from evaporating primordial black holes. In the event that speculative large extra dimension theories are correct, CERN's Large Hadron Collider may be able to create micro black holes and observe their evaporation.