Dark Matter in Galaxies Course | Education. Online. Free. | iversity:
"There is something out there in space, something invisible we have a hard time to understand. But we can be certain of one thing: It played a major role in the formation of our and any other galaxy!"
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Sunday, October 20, 2013
2013 TV135 - Wikipedia, the free encyclopedia
2013 TV135 - Wikipedia, the free encyclopedia:
"2013 TV135 is a PHO (Potentially hazardous object) and has a rating of 1 out of 10 on the Torino scale for impact hazards; this indicates that it "poses no unusual level of danger".[3] With a short observation arc of 10 days, it has about a 1 in 14,000 chance of impacting Earth on August 26, 2032.[3]"
'via Blog this'
"2013 TV135 is a PHO (Potentially hazardous object) and has a rating of 1 out of 10 on the Torino scale for impact hazards; this indicates that it "poses no unusual level of danger".[3] With a short observation arc of 10 days, it has about a 1 in 14,000 chance of impacting Earth on August 26, 2032.[3]"
'via Blog this'
Monday, September 23, 2013
Thursday, September 12, 2013
Voyager 1 Finally Leaves Solar System—for Real This Time: Scientific American
Voyager 1 Finally Leaves Solar System—for Real This Time: Scientific American:
"Voyager 1 was starting to get a reputation as the spacecraft that cried wolf, after scientists repeatedly claimed it was leaving the solar system, only to change their minds and say it wasn’t quite there yet. Now researchers say new evidence shows Voyager really has departed the sun’s sphere of influence and become the first man-made object to reach interstellar space."
'via Blog this'
"Voyager 1 was starting to get a reputation as the spacecraft that cried wolf, after scientists repeatedly claimed it was leaving the solar system, only to change their minds and say it wasn’t quite there yet. Now researchers say new evidence shows Voyager really has departed the sun’s sphere of influence and become the first man-made object to reach interstellar space."
'via Blog this'
Monday, September 9, 2013
Monday, July 1, 2013
Fast-Moving Blaze Kills 19 Firefighters in Central Arizona - NYTimes.com
Fast-Moving Blaze Kills 19 Firefighters in Central Arizona - NYTimes.com:
"CONGRESS, Ariz. — Nineteen firefighters were killed on Sunday battling a fast-moving wildfire menacing a small town in central Arizona."
'via Blog this'
"CONGRESS, Ariz. — Nineteen firefighters were killed on Sunday battling a fast-moving wildfire menacing a small town in central Arizona."
'via Blog this'
Sunday, June 30, 2013
Saturday, May 25, 2013
Up, Up and Away
By CATHERINE RAMPELL
Published: May 25, 2013
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THE values of gold and silver have dropped like a stone in international trading markets. Coffee futures are hovering near athree-year low. But the price of one commodity has been rising as if it were lighter than air — and in this case, well, it is.
The market value of refined helium gas has nearly doubled over the past five years, even as the Standard & Poor’s benchmark commodities index, the GSCI, has fallen by some 20 percent.
It’s not a bubble. That’s because the price has been driven up less by speculation than by old-fashioned fundamentals: there’s more demand for the gas than ever and supply has not been able to keep up. Call it, rather, “the helium balloon.”
The world, it seems, is running short of the second most abundant element in the universe — and that’s creating a major problem in a wide array of businesses.
You may think of helium as important only to birthday-party balloons and Frankie Valli impressions, but the gas has an extraordinary number of biomedical, industrial and national security uses, playing critical roles in the production or operation of M.R.I. machines, fiber-optic cables, flat-screen TVs, semiconductors, space launches, welding, military surveillance, air-to-air missile guidance and much else.
For many of those uses, moreover, there are no known substitutes. Helium’s low boiling and melting points, the lowest of any element, make it ideal for cryogenic applications. And as the second lightest element, it’s great for lifting things, from weather balloons to national-security dirigibles.
While abundant in the universe writ large, however, helium is not easy to capture. Much of the helium on earth leaks into space, and with only 5.2 parts per million in the air, it’s not economically feasible with current technology to extract the stuff from the atmosphere. Instead, most of the helium that is sold on the market originates in natural gas fields underground and is salvaged as a byproduct of natural gas. Even then, only a handful of fields have a high enough concentration of helium to make extracting it financially worthwhile.
What makes this market saga particularly quirky, though, is the role played by the United States government. For much of the 20th century, the federal government had a domestic monopoly on the production of helium, which was used for airships, missile guidance and other national security measures. In 1960, it began a program to stockpile the helium it was extracting in an underground reservoir near Amarillo, Tex., amassing a debt of $1.3 billion in the process.
When, in the mid-1990s, lawmakers decided to pay down that debt, the government gradually started to sell off its helium holdings. But Congress made some odd decisions in that regard.
Typically, when the government wants to sell a public resource or asset to the private sector — as with the wireless spectrum — economists advise holding an auction so taxpayers get the highest price that the market will bear.
At the time, though, Congress determined that the market price was too low to cover its debt, according to John R. Campbell, publisher of CryoGas International and president of J. R. Campbell & Associates, one of the world’s leading consulting firms on gases. So instead lawmakers just set a minimum price for the government’s helium — one that was about twice what buyers were paying on the open market at the time.
At first, buyers balked. But over the decade that followed, demand for helium in the private sector increased so much — particularly in places like Taiwan and Korea, where the gas is used in manufacturing electronics — that the government’s price inevitably became the market one. Today, the price — still set by a government formula — is, if anything, lower than what the market would otherwise bear.
Just look at what has happened to the price of refined helium, the form of the gas sold to M.R.I. manufacturers and the like, which has nearly quadrupled since 2000.
The sky-high refined helium prices have forced Tokyo Disneyland to suspend the sale of balloons and disrupted the work of academic scientists who use helium for research projects in cryogenics and nanotechnology. And the shortages are about to get worse.
That’s because, due to an odd technicality in the helium privatization law enacted in 1996, the government will effectively end sales from the reserve once its debt is paid off — something that could happen as early as October, even though there’s still a huge reservoir of helium left in the till.
Walter L. Nelson, director of helium sourcing and supply chain at Air Products and Chemicals, told a Senate committee earlier this month that “30 percent of the worldwide supply will be essentially locked up, causing prices to skyrocket.” That, he said, will leave some users with no ability to get the gas and will mean “chaos in the economic sectors that now rely on helium.”
Lawmakers are now considering revising the law to let reserve sales continue even after the debt is paid, which helium users say would give other private sources of the gas in places like Qatar enough time to finally get onstream. There is also talk of introducing regular auctions to allow the helium price to float up or down to wherever the “true” market price is.
But the bottom line, says David C. Mowery, a professor at the Haas School of Business at the University of California, Berkeley, is that “you’ve had lawyers doing natural resource economics. That’s almost never what you want.”
No doubt, plenty of TV manufacturers, aerospace technicians and sad clowns would agree.
An economics reporter for The New York Times.
A version of this news analysis appeared in print on May 26, 2013, on page SR4 of the New York edition with the headline: Up, Up and Away.
Friday, May 24, 2013
La Jornada en Internet: Utiliza universitario técnica de Interferometría para medir distancias cósmicas
La Jornada en Internet: Utiliza universitario técnica de Interferometría para medir distancias cósmicas:
"El astrofísico Laurent Raymond Loinard Corvaisier, investigador del Centro de Radioastronomía y Astrofísica de la UNAM, emplea desde hace 10 años una técnica de triangulación que utiliza la rotación de la Tierra alrededor del Sol."
'via Blog this'
"El astrofísico Laurent Raymond Loinard Corvaisier, investigador del Centro de Radioastronomía y Astrofísica de la UNAM, emplea desde hace 10 años una técnica de triangulación que utiliza la rotación de la Tierra alrededor del Sol."
'via Blog this'
Thursday, May 23, 2013
La Jornada en Internet: Localizan alrededor de 5 mil pinturas rupestres en la Sierra de Tamaulipas
La Jornada en Internet: Localizan alrededor de 5 mil pinturas rupestres en la Sierra de Tamaulipas:
"Su importancia radica en que con base en ellas hemos podido documentar la presencia de grupos prehispánicos en Burgos, donde antes se decía que no había nada, cuando en realidad estuvo habitado por una o varias culturas, señalan investigadores."
'via Blog this'
"Su importancia radica en que con base en ellas hemos podido documentar la presencia de grupos prehispánicos en Burgos, donde antes se decía que no había nada, cuando en realidad estuvo habitado por una o varias culturas, señalan investigadores."
'via Blog this'
Tuesday, May 21, 2013
Crews Search for Survivors in Oklahoma After Tornado - NYTimes.com
Crews Search for Survivors in Oklahoma After Tornado - NYTimes.com:
"Much of the tornado damage was in the suburb of Moore, where rescue workers struggled to make their way through debris-clogged streets and around downed power lines to those who were feared trapped under mountains of rubble. Rescue workers equipped with thermal-imaging equipment and dogs sifted through plywood boards, upended cars and steel beams where houses and shops once stood."
'via Blog this'
"Much of the tornado damage was in the suburb of Moore, where rescue workers struggled to make their way through debris-clogged streets and around downed power lines to those who were feared trapped under mountains of rubble. Rescue workers equipped with thermal-imaging equipment and dogs sifted through plywood boards, upended cars and steel beams where houses and shops once stood."
'via Blog this'
Sunday, May 19, 2013
Antarctic Neutrino Observatory Detects Unexplained High-Energy Particles: Scientific American
Antarctic Neutrino Observatory Detects Unexplained High-Energy Particles: Scientific American:
"A preliminary analysis from the IceCube detector reveals more than two dozen neutrinos of unknown origin"
'via Blog this'
"A preliminary analysis from the IceCube detector reveals more than two dozen neutrinos of unknown origin"
'via Blog this'
6 Women Scientists Who Were Snubbed Due to Sexism
6 Women Scientists Who Were Snubbed Due to Sexism:
"Despite enormous progress in recent decades, women still have to deal with biases against them in the sciences."
'via Blog this'
"Despite enormous progress in recent decades, women still have to deal with biases against them in the sciences."
'via Blog this'
Wednesday, May 15, 2013
Vinnie Quiz 5-15
Vinnie Caringella
Astronomy
5-15
1.Yes.
2. Yes.
3.That the expansion of the universe is accelerating.
4.Saul Perlmutte, Brian P. Schmidt and Adam G. Riess
5.White dwarfs.
6.The universe is 27.4% baryonic matter and dark matter and 71.3% dark energy.
6.The universe is 27.4% baryonic matter and dark matter and 71.3% dark energy.
7.The figure shows different models for the expansion of the universe.
8.The supernova data model.
9.14 billion years old
10,Yes, dark matter.
Final Vinnie Caringella
Vinnie Caringella
Astronomy
5-15-13
Final
1.A
2.B
3.C
4.D
5.B
6. B
7.D
8.C
9.D
10.B
Tuesday, May 14, 2013
Douglas Middendorf's Quiz
Will the universe continue expanding forever?
Which standard candles were used to measure the acceleration of the universe?
Yes.
Is the expansion of the universe accelerating?
Yes.
What discovery received the Physics Noble Prize in 2011?
That the expansion of the universe is accelerating.
Name the three scientists that received the prize?
Saul Perlmutte, Brian P. Schmidt and Adam G. Riess
White dwarfs.
What are the fractions of baryonic matter, dark matter, and dark energy?
The universe is 27.4% baryonic matter and dark matter and 71.3% dark energy.
Describe Figure 16.16 of the textbook.
The figure shows different models for the expansion of the universe.
Which model fits best?
The supernova data model.
According to this model, which is the age of the universe?
14 billion years old
Is there something opposing gravitational attraction in the universe as a whole?
Yes, dark matter.
Final
- How does solar activity vary with time?
- How do we measure stellar masses?
- How do stars form?
- What is a neutron star?
- How do halo stars tell us about our galaxy's history?
- How are galaxies grouped together?
- What is the role of dark matter in galaxy formation?
- What are the largest structures in the universe?
- Will the universe continue expanding forever?
- Is the expansion of the universe accelerating?
A.The sunspot cycle , or the variation in the number of sunspots on the Sun's surface has an average period of 11 years. The magnetic field flip-flops every 11 years or so, resulting in a 22-year magnetic cycle. Sunspots first appear at mid-latitudes at solar minimum, then become increasingly more common near the Sun's equator as the next minimum approaches, and sometimes seem to be absent altogether.
B. The sunspot cycle , or the variation in the number of sunspots on the Sun's surface has an average period of 22 years. The magnetic field flip-flops every 22 years or so, resulting in a 44-year magnetic cycle. Sunspots first appear at mid-latitudes at solar minimum, then become increasingly more common near the Sun's equator as the next minimum approaches, and sometimes seem to be absent altogether.
C. The sunspot cycle , or the variation in the number of sunspots on the Sun's surface has an average period of 33 years. The magnetic field flip-flops every 33 years or so, resulting in a 66-year magnetic cycle. Sunspots first appear at mid-latitudes at solar minimum, then become increasingly more common near the Sun's equator as the next minimum approaches, and sometimes seem to be absent altogether.
D. The sunspot cycle , or the variation in the number of sunspots on the Sun's surface has an average period of 44 years. The magnetic field flip-flops every 44 years or so, resulting in a 88-year magnetic cycle. Sunspots first appear at mid-latitudes at solar minimum, then become increasingly more common near the Sun's equator as the next minimum approaches, and sometimes seem to be absent altogether.
A. We can measure the masses of stars in binary star systems using Newton's version of Kepler's first law if we know the orbital period and separation of the two stars.
B. We can measure the masses of stars in binary star systems using Newton's version of Kepler's third law if we know the orbital period and separation of the two stars.
C. We can measure the masses of stars in binary star systems using Newton's version of Kepler's second law if we know the orbital period and separation of the two stars.
D.We can measure the masses of stars in binary star systems using Newton's version of Kepler's fourth law if we know the orbital period and separation of the two stars.
A. Stars are born in cold, relatively dense molecular clouds. As a cloud fragment collapses under electromagnetism, it becomes a rapidly rotating protostar surrounded by a spinning disk of gas in which planets may form. The protostar may also fire jets of matter outward along its poles.
B. Stars are born in cold, relatively dense molecular clouds. As a cloud fragment collapses under the strong force, it becomes a rapidly rotating protostar surrounded by a spinning disk of gas in which planets may form. The protostar may also fire jets of matter outward along its poles.
C. Stars are born in cold, relatively dense molecular clouds. As a cloud fragment collapses under gravity, it becomes a rapidly rotating protostar surrounded by a spinning disk of gas in which planets may form. The protostar may also fire jets of matter outward along its poles.
D. Stars are born in cold, relatively dense molecular clouds. As a cloud fragment collapses under the weak force, it becomes a rapidly rotating protostar surrounded by a spinning disk of gas in which planets may form. The protostar may also fire jets of matter outward along its poles.
A. A neutron star is the ball of neutrinos created by the collapse of the iron core in a massive star supernova. It resembles a giant atomic nucleus 10 kilometers in radius and with more mass than the Sun.
B. A neutron star is the ball of electrons created by the collapse of the iron core in a massive star supernova. It resembles a giant atomic nucleus 10 kilometers in radius and with more mass than the Sun.
C. A neutron star is the ball of top quarks created by the collapse of the iron core in a massive star supernova. It resembles a giant atomic nucleus 10 kilometers in radius and with more mass than the Sun.
D. A neutron star is the ball of neutrons created by the collapse of the iron core in a massive star supernova. It resembles a giant atomic nucleus 10 kilometers in radius and with more mass than the Sun.
A. The halo generally contains only old, low-mass stars that have a much smaller proportion of heavy elements than stars in the disk. Halo stars therefore must have formed early in the galaxy's history, before the gas settled into a disk.
B. The halo generally contains only young, high-mass stars that have a much smaller proportion of heavy elements than stars in the disk. Halo stars therefore must have formed early in the galaxy's history, before the gas settled into a disk.
C. The halo generally contains only young, high-mass stars that have a much greater proportion of heavy elements than stars in the disk. Halo stars therefore must have formed early in the galaxy's history, before the gas settled into a disk.
D. The halo generally contains only old, high-mass stars that have a much greater proportion of heavy elements than stars in the disk. Halo stars therefore must have formed early in the galaxy's history, before the gas settled into a disk.
A.Spiral galaxies tend to collect in groups that contain hundred to thousands of galaxies. Elliptical galaxies are more common in clusters of galaxies, which contain up to several dozen galaxies, all bound together by gravity.
B. Spiral galaxies tend to collect in groups that contain up to several dozen galaxies. Elliptical galaxies are more common in clusters of galaxies, which contain hundreds to thousands of galaxies, all bound together by gravity.
C. Spiral galaxies tend to collect in groups that contain up to millions of galaxies. Elliptical galaxies are more common in clusters of galaxies, which contain billions of galaxies, all bound together by gravity.
D. Spiral galaxies tend to collect in groups that contain billions of galaxies. Elliptical galaxies are more common in clusters of galaxies, which contain trillions of galaxies, all bound together by gravity.
A.Because most of a galaxy's mass is in the form of dark matter, the gravity of that dark matter is probably what formed protogalactic clouds and galaxies from slight density enhancements in the late universe.
B. Because most of a galaxy's mass is in the form of dark matter, the gravity of that dark matter is probably what formed protogalactic clouds and galaxies from huge density enhancements in the early universe.
C. Because most of a galaxy's mass is in the form of dark matter, the gravity of that dark matter is probably what formed protogalactic clouds and galaxies from slight density enhancements in the early universe.
D. Because most of a galaxy's mass is in the form of dark energy, the gravity of that dark energy is probably what formed protogalactic clouds and galaxies from slight density enhancements in the early universe.
A.Galaxies appear to be distributed in gigantic voids. These giant structures trace their origin directly back to regions of slightly enhanced density late in time.
B. Galaxies appear to be distributed in gigantic chains and sheets that surround great voids. These giant structures trace their origin directly back to regions of slightly enhanced density early in time.
C. Galaxies appear to be distributed in gigantic chains and sheets that surround great voids. These giant structures trace their origin directly back to regions of huge enhanced density early in time.
D. Galaxies appear to be distributed in gigantic chains and sheets that surround great voids. These giant structures trace their origin directly back to regions of huge enhanced density late in time.
A. Even before we consider the possibility of dark energy, the evidence points to eternal expansion. The critical density is the average matter density the universe would need for the strength of gravity to eventually halt the expansion. The overall matter density of the universe appears to be only about 25% of the critical density.
B. Even before we consider the possibility of dark matter, the evidence points to eternal expansion. The critical density is the average matter density the universe would need for the strength of gravity to eventually halt the expansion. The overall matter density of the universe appears to be only about 125% of the critical density.
C. Even before we consider the possibility of dark matter, the evidence points to eternal expansion. The critical density is the average matter density the universe would need for the strength of gravity to eventually halt the expansion. The overall matter density of the universe appears to be only about 225% of the critical density.
D. Even before we consider the possibility of dark energy, the evidence points to eternal expansion. The critical density is the average matter density the universe would need for the strength of gravity to eventually halt the expansion. The overall matter density of the universe appears to be only about 325% of the critical density.
A.Observations of distant brown dwarfs indicate that the expansion is speeding up. No one knows the nature of the mysterious force due to dark energy that could be causing this acceleration.
B.Observations of distant supernovae indicate that the expansion is speeding up. No one knows the nature of the mysterious force due to dark energy that could be causing this acceleration.
C. Observations of distant neutron stars indicate that the expansion is speeding up. No one knows the nature of the mysterious force due to dark energy that could be causing this acceleration.
D. Observations of distant white dwarfs indicate that the expansion is speeding up. No one knows the nature of the mysterious force due to dark energy that could be causing this acceleration.
Quiz 05/07/13
- How do we observe the life histories of galaxies? Images of the deep universe allow us to study galaxies at many different distances and therefore many different ages.
- How did galaxies form? Our most successful models of galaxy formation suggest that protogalactic clouds formed in regions of slightly enhanced density in the early universe.
- Why do galaxies differ? Elliptical galaxies may have formed from protogalactic clouds that were spinning more slowly or were denser than those that formed spiral galaxies. Starburst galaxies are forming stars so quickly that they will run out of star-forming clouds in just a few hundred million years.
- What are quasars? Quasars are extremely luminous and are a very energetic and distant active galactic nucleus.
- What is the power source for quasars and other active galactic nuclei? Quasars are probably powered by matter falling into supermassive black holes.
- Do supermassive black holes really exist? Yes
- What does QUASAR mean? A quasi-stellar radio source.
- Who is Maarten Schmidt? Maarten Schmidt is a Dutch astronomer who measured the distances of quasars. He later began a study of the light spectra of radio sources. In 1963, using the famous 200-inch reflector telescope at the Palomar Observatory, Schmidt identified the visible object corresponding to one of these radio sources, known as 3C 273 and also studied its spectrum.
- What is Cosmology? The study of the origins and eventual fate of the universe.
- What is the Cosmological Principle? The Cosmological Principle is the dynamical structure principle that falls from the working assumption that the distribution of matter in the universe is homogeneous and isotopic when viewed on a large enough scale, since the forces are expected to act uniformly throughout the universe, and should, therefore, produce no observable irregularities in the large scale structuring over the course of evolution of the matter field that was initially laid down by the big bang.
Quiz 05/09/13
- What do we mean by dark matter and dark energy? Dark matter is the name given to the unseen mass whose gravity governs that observed motions of stars and gas clouds.
- What is the evidence for dark matter in galaxies? Orbital velocities within galaxies remain nearly constant at large radii, indicating that most of the matter lies outside the visible regions.
- What is the evidence for dark matter in clusters of galaxies? Masses measured from galaxy motions, temperature of hot gas, and gravitational lensing all indicate that the vast majority of matter in clusters is dark.
- Does dark matter really exist? Yes
- What might dark matter be made of? Nonbaryonic particles
- What is the role of dark matter in galaxy formation? The gravity of dark matter seems to be what draws gas together into protogalactic clouds, initiating the process of galaxy formation.
- What are the largest structures in the universe? Galaxies
- Who was Fritz Zwicky? He was a swiss astronomer. He made many important contributions in theoretical and observational astronomy.
- Who is Vera Rubin? Vera Cooper Rubin is an American astronomer. In 1951, she completed her education and she made one of the first observations and deviations from the Hubble flow in the motions of galaxies.
- Who is Alex Filippenko? Alex Filippenko is an American astrophysicist and professor of astronomy at the University of California, Berkeley. His research focuses on supernovae and active galaxies at optical, ultraviolet, and near-infrared wavelengths.
Quiz 05/14/13
- Will the universe continue expanding forever? No
- Is the expansion of the universe accelerating? Yes
- What discovery received the Physics Noble Prize in 2011? The published observations of Type 1a Supernovae by the High-z Supernova Search Team followed in 1999 by the Supernova Cosmology Project suggested the expansion of the universe is accelerating.
- Name the three scientists that received the prize? Perlmutter, Schmidt, and Reiss
- Which standard candles were used to measure the acceleration of the universe? Standard candles
- What are the fractions of baryonic matter, dark matter, and dark energy? 71.3% of dark energy and 27.4% of a combination of dark matter and baryonic matter.
- Describe Figure 16.16 of the textbook. Data from white dwarf supernovae are shown along with four possible models for the expansion of the universe. Each curve shows how the average distance between galaxies changes with time for a particuular model.
- Which model fits best? The supernova data firs the accelerating universe better than the other models.
- According to this model, which is the age of the universe? 14 billion years
- Is there something opposing gravitational attraction in the universe as a whole? Dark matter
Monday, May 13, 2013
QUIZ - 5.14.13
1. Will the universe continue expanding forever?
- Current measurements indicate that there is not enough dark matter to prevent the universe from expanding forever.
- An accelerating universe is the best explanation for the distances we measure when using white dwarf supernovae as standard candles.
- The Nobel Prize in Physics 2011 was divided; one half awarded to Saul Perlmutter, the other half jointly to Brian P. Schmidt and Adam G. Reiss "for the discovery of the accelerating expansion of the Universe through observations of distant supernovae."
- The three scientists that received that prize were Saul Perlmutter, Brian P. Schmidt, and Adam G. Reiss.
- The research teams looked for a certain type of supernova, called a SUPERNOVA 1A, which happens when a white dwarf star gains enough extra matter to make it unstable. This sort of supernova is so powerful that it can outshine even a galaxy. Since we understand this sort of supernova well, it can be used as a "standard candle" to measure the distance to the supernovas & this measurement can be used to calculate the expansion rate of the universe over time.
- The fraction for both baryonic matter and dark matter is 27.4%. The fraction for dark energy is 71.3%.
- The figure in 16.16 of the textbook is four possible models for the expansion of the universe. Each individual curve is shown how the average distance between galaxies changes with time for a particular model.
- The model that fits best and is greatest at presenting/explaining the accelerating universe to us would be the supernova data model.
- According to this model, the age of the universe is 14 billion years old.
- Yes, there is something opposing gravitational attraction in the universe as a whole and that would be dark matter.
Sunday, May 12, 2013
Quiz 5/12/2013
1. Will the Universe continue expanding forever?
The universe does not appear to contain enough dark matter to prevent it from expanding forever.
2. Is the expansion of the universe accelerating?
The measurements show that gravity is not slowing the expansion of the universe down at all. Instead, the expansion of the universe seems to be accelerating.
3. What discovery received the Physics Nobel Prize in 2011?
The published observations of Type 1a Supernovae by the High-z Supernova Search Team followed in 1999 by the Supernova Cosmology Project suggested the expansion of the universe is accelerating. The Nobel prize was awarded in this work.
4. Name the three scientists that received the prize?
Perlmutter, Schmidt, and Reiss received the prize.
5. Which standard candles were used to measure the acceleration of the universe?
Observations of white dwarf supernovae were used as standard candles.
6. What are the fractions of baryonic matter, dark matter, and dark energy?
71.3% of dark energy and 27.4% of a combination of dark matter and baryonic matter.
7. Describe 16.6 of the textbook.
Data from white dwarf supernovae are shown along with four possible models for the expansion of the universe. Each curve shows how the average distance between galaxies changes with time for a particuular model.
8. Which model fits best?
The supernova data firs the accelerating universe better than the other models.
9. According to this model, which is the age of the universe?
According to the model, the universe is 14 billion years for an accelerating universe.
10. Is there something opposing gravitational attraction in the universe as a whole?
Dark matter.
5-10-13 Vinnie
Vinnie Caringella
5-10-13
Astronomy
5-10-13
Astronomy
QUIZ
1. Dark matter is the name
given to the unseen mass whose gravity governs that observed motions of stars
and gas clouds.
2. Orbital velocities within
galaxies remain nearly constant at large radii, indicating that most of the
matter lies outside the visible regions.
3. Masses measured from
galaxy motions, temperature of hot gas, and gravitational lensing all indicate
that the vast majority of matter in clusters is dark.
4. Either dark matter exists
or our understanding of our gravity must be revised.
5.Most astronomers suspect
that dark matter is made of nonbaryonic particles that have not yet been
discovered.
6.The gravity of dark matter
seems to be what draws gas together into protogalactic clouds, initiating the
process of galaxy formation.
7. Galaxies appear to be
distributed in gigantic chains and sheets that surround great voids.
8. Fritz Zwicky was a Swiss
astronomer. He worked most of his life at the California Institute of
Technology.
9. Vera Cooper Rubin is
an American astronomer. In 1951, she completed her education and she made one of
the first observations and deviations from the Hubble flow in the motions of
galaxies.
10. Alex Filippenko is an
American astrophysicist and professor of astronomy at the University of
California, Berkeley.
Thursday, May 9, 2013
Quiz
- Will the universe continue expanding forever?
- Is the expansion of the universe accelerating?
- What discovery received the Physics Noble Prize in 2011?
- Name the three scientists that received the prize?
- Which standard candles were used to measure the acceleration of the universe?
- What are the fractions of baryonic matter, dark matter, and dark energy?
- Describe Figure 16.16 of the textbook.
- Which model fits best?
- According to this model, which is the age of the universe?
- Is there something opposing gravitational attraction in the universe as a whole?
Hint: Check Wikipedia for Dark Energy, in particular the groups High-z Supernova Search Team, and Supernova Cosmology Project.
Fire and Ice
Some say the world will end in fire,
Some say in ice.
From what I've tasted of desire
I hold with those who favor fire.
But if it had to perish twice,
I think I know enough of hate
To say that for destruction ice
Is also great
And would suffice.
Robert Frost
Some say in ice.
From what I've tasted of desire
I hold with those who favor fire.
But if it had to perish twice,
I think I know enough of hate
To say that for destruction ice
Is also great
And would suffice.
Robert Frost
Wednesday, May 8, 2013
QUIZ - 5.9.13
1. What do we mean by dark matter and dark energy?
- Dark matter is the name given to the unseen mass whose gravity governs that observed motions of stars and gas clouds. Dark energy is the name given to whatever might be causing the expansion of the universe to accelerate.
- Orbital velocities within galaxies remain nearly constant at large radii, indicating that most of the matter lies outside the visible regions.
- Masses measured from galaxy motions, temperature of hot gas, and gravitational lensing all indicate that the vast majority of matter in clusters is dark.
- Either dark matter exists or our understanding of our gravity must be revised.
- There does not seem to be enough normal (baryonic) matter to account for all the dark matter, so most astronomers suspect that dark matter is made of (nonbaryonic) particles that have not yet been discovered.
- The gravity of dark matter seems to be what draws gas together into protogalactic clouds, initiating the process of galaxy formation.
- Galaxies appear to be distributed in gigantic chains and sheets that surround great voids.
- Fritz Zwicky was a Swiss astronomer. He worked most of his life at the California Institute of Technology. He made many important contributions in theoretical and observational astronomy. His scientific work included ionic crystals / electrolytes, supernovae / neutron stars, standard candles, gravitational lenses, dark matter, tired light, morphological analysis, Catalog of Galaxies and Clusters, and finally guns / goblins.
- Vera Cooper Rubin is an American astronomer. In 1951, she completed her education and she made one of the first observations and deviations from the Hubble flow in the motions of galaxies. She argued that galaxies might be rotating around unknown centres, rather than simply moving outwards, as suggested by the Big Bang theory at that time. In 1954, her PhD these for graduation concluded that that galaxies clumped together, rather than being randomly distributed through the universe. The idea that clusters of galaxies existed was not pursued seriously by others until two decades later. In 1965, she became the first woman "allowed" to use the instruments at the Palomar Observatory. In 1965, she landed a job at the Department of Terrestrial Magnetism at the Carnegie Institution of Washington and has worked there as an astronomer since that time. Her work is best described as "Galactic and extragalactic dynamics; large-scale structure and dynamics of the universe." In the 1970's, Ms. Rubin produced clear observational evidence that finally convinced astronomers worldwide that the vast bulk of the mass in the universe is invisible and unknown in origin and character. (Dark Matter)
- Alex Filippenko is an American astrophysicist and professor of astronomy at the University of California, Berkeley. His research focuses on supernovae and active galaxies at optical, ultraviolet, and near-infrared wavelengths. Mr. Filippenko was a member of the Supernova Cosmology Project and the High-z Supernova Search Team that used observations of extragalactic supernovae to discover the accelerating universe. The universal acceleration implies the existence of dark energy and was voted the top science breakthrough of 1998 by Science magazine. Mr. Filippenko developed and runs the Katzman Automatic Imaging Telescope. KAIT is a fully robotic telescope which conducts the Lick Observatory Supernova Search, the most successful nearby supernova search. He is also a member of the Nuker Team which uses the Hubble space telescope to examine supermassive black holes and determined the relationship between a galaxy's central black hole's mass and velocity dispersion. The Thompson-Reuters "incites" index ranked Filippenko as the most cited researcher in space science for the ten-year period between 1996 and 2006. Alex Filippenko is frequently featured in the History Channel series, The Universe.
Tuesday, May 7, 2013
Doug Middendorf's Quiz
What do we mean by dark matter and dark energy?
Energy and matter that emits little or no light but interacts with celestial objects.
What is the evidence for dark matter in galaxies?
Weighing spiral galaxies with rotational curves and weighing elliptical galaxies.
What is the evidence for dark matter in clusters of galaxies?
Orbital velocities, x-ray emission and gravitational lensing.
Does dark matter really exist?
Yes, or our current understanding of gravity is wrong.
What might dark matter be made of?
MACHOs and WIMPs.
What is the role of dark matter in galaxy formation?
It clumps together and manipulates celestial objects with gravity.
What are the largest structures in the universe?
Large quasar groups
Who was Fritz Zwicky?
Zwicky found that clusters have huge mass to light ratios
Who is Vera Rubin?
measured the rotation curves for various spiral galaxies.
Who is Alex Filippenko?
An American astrophysicist and professor of astronomy at the University of California, Berkeley.
Doug Middendorf's Quiz
How do we observe the life histories of galaxies?
By categorizing them.
How did galaxies form?
Galaxies form from giant clouds of condensing gas and dust.
Why do galaxies differ?
Collisions and the formations affect the way galaxies turn out.
What are quasars?
Active galactic nucleus.
What is the power source for quasars and other active galactic nuclei?
Black holes.
Do supermassive black holes really exist?
Almost certainly.
What does QUASAR mean?
Quasi-stellar radio source.
Who is Maarten Schmidt?
Maarten Schmidt is a Dutch astronomer who measured the distances of quasars.
What is Cosmology?
The study of the origins and eventual fate of the universe.
What is the Cosmological Principle?
The universe looks about the same no matter where you are within it.
Quiz
- What do we mean by dark matter and dark energy?
- What is the evidence for dark matter in galaxies?
- What is the evidence for dark matter in clusters of galaxies?
- Does dark matter really exist?
- What might dark matter be made of?
- What is the role of dark matter in galaxy formation?
- What are the largest structures in the universe?
- Who was Fritz Zwicky?
- Who is Vera Rubin?
- Who is Alex Filippenko?
Hint: Check Dark Matter, and Dark Energy in Wikipedia.
5/7/13 Quiz VC
Vinnie Caringella
Astronomy
5-7-13
Quiz
1. Images of the deep universe allow us to study galaxies at many different distances
2.
Our models of galaxy formation suggest that protogalactic clouds formed in
regions of slightly enhanced density in the early universe.
3.
Elliptical galaxies may have formed from protogalactic clouds that were spinning
more slowly or were denser than those that formed spiral galaxies.
4.
Quasars are extremely luminous and are a very energetic and distant active
galactic nucleus.
5.
Quasars are probably powered by matter falling into supermassive black holes.
6.
Observations of rapidly orbiting material at the centers of galaxies indicate
that at least some galaxies, and perhaps all of them, harbor supermassive black
holes.
7.
A quasi-stellar radio source.
8.
Maarten Schmidt is a Dutch astronomer who measured the distances of
quasars.
9.
Cosmology is the study of the origins and eventual fate of the universe.
10.
The Cosmological Principle is the dynamical structure principle that falls from
the working assumption that the distribution of matter in the universe is
homogeneous and isotopic when viewed on a large enough scale.
Monday, May 6, 2013
Alexei Filippenko - Wikipedia, the free encyclopedia
Alexei Filippenko - Wikipedia, the free encyclopedia:
"Alexei Vladimir Filippenko (born July 25, 1958) is an American astrophysicist and professor of astronomy at the University of California, Berkeley. Filippenko graduated from Dos Pueblos High School in Goleta, CA. He received a Bachelor of Arts in physics from the University of California, Santa Barbara in 1979 and a Ph.D. in astronomy from the California Institute of Technology in 1984, where he was a Hertz Foundation Fellow. He was a Miller Fellow at UC Berkeley and was subsequently appointed to a faculty position at the same institution. His research focuses on supernovae and active galaxies at optical, ultraviolet, and near-infrared wavelengths."
'via Blog this'
"Alexei Vladimir Filippenko (born July 25, 1958) is an American astrophysicist and professor of astronomy at the University of California, Berkeley. Filippenko graduated from Dos Pueblos High School in Goleta, CA. He received a Bachelor of Arts in physics from the University of California, Santa Barbara in 1979 and a Ph.D. in astronomy from the California Institute of Technology in 1984, where he was a Hertz Foundation Fellow. He was a Miller Fellow at UC Berkeley and was subsequently appointed to a faculty position at the same institution. His research focuses on supernovae and active galaxies at optical, ultraviolet, and near-infrared wavelengths."
'via Blog this'
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