by Rod P 95 Replies latest watchtower bible
The surrounding objects are probably stars of our own galaxy
When I look at the image it looks like a nebula, only more organized. I would guess that it is just a very organized nebula that is relatively close to the earth.
I'm sorry, but I am confused. What do you mean by "galaxy"? I don't understand what that is. (No, I'm not being a smart-ass... seriously, what is a galaxy and how do you know that the object in the image is a "galaxy"?)
When I look at the image it looks like a nebula, only more organized. I would guess that it is just a very organized nebula that is relatively close to the earth. I'm sorry, but I am confused. What do you mean by "galaxy"? I don't understand what that is. (No, I'm not being a smart-ass... seriously, what is a galaxy and how do you know that the object in the image is a "galaxy"?)
Allright,
There is a difference made between nebulas are galaxy's.
Galaxy is a huge group of stars, that is outside out own galaxy the milky way. (galaxy of stars).
A nebula is made of gas and is inside our own milky way. (in other galaxies we can not see them, they are not very bright).
There are different types of galaxy's, the most common have spiral arms, like our own galaxy the milky way. You can recognice them on the distance (yes redshift and other methods). With a nebula you see the dust, with a galaxy you just see many starts close together, that it looks like dust.
Here a pic of a galaxy and a nebula:
Galaxy is a huge group of stars, that is outside out own galaxy the milky way. (galaxy of stars).
How do you know this? When I look at the image of the object it appears to be a swirling cloud of gas. Maybe there is a very massive object in the middle that has captured these gasses and is making them glow because of the friction.
What makes you think that object has thousands of stars? All I see is a fuzzy organized cloud shaped like a swirl.
How do you know it is outside our own galaxy? For all we know it is only 5000 light years away (a short distance compared to the 100,000 light year diameter of our galaxy)
(Again, I'm not being a smart ass... this is going somewhere)
How do you know this? When I look at the image of the object it appears to be a swirling cloud of gas. Maybe there is a very massive object in the middle that has captured these gasses and is making them glow because of the friction.What makes you think that object has thousands of stars? All I see is a fuzzy organized cloud shaped like a swirl.
How do you know it is outside our own galaxy? For all we know it is only 5000 light years away (a short distance compared to the 100,000 light year diameter of our galaxy)
It is not a strange question actually. It was long not understood. One of the first signs were that the galaxies were found equally in all directions. THe nebulas were found mostly in the direction of the disk of our own galaxy. So in the area of the visible band the milkey way at the sky.
When a star becomes a supernova it increases brightness by a huge factor. It is found in the other galaxies also. They are recognicable because of the time it takes to become bright, a spectral analysis etc. This sugegsted a far creater distance.
It was first discovered with stars called Cepheid variable stars. We can see some individual stars is closeby galaxies. These cepheid stars are very bright individual stars who have some variable brightness period. We have found them in our own galaxy and in other galaxies. They seem to be all about equally bright in our own galaxy, so it can be interpolated to other galaxies. The brightness is of course a messure of the distance, how more far, how less bright it appears. When you have an indication of how bright the star should be, you can estimate its distance.
The result is that the galaxy in the picture above is about 2 milion lightyears away. It is considered the object that is most far that is still visible with human eye alone.
p.s. It must have been quite a shock for creationistm because 2 million lightyears away, means of course two million years old.
Danny
(Again, I'm not being a smart ass... this is going somewhere)
Ok, I'll get to my point.
Until Hubble discovered the relationship between the distance of an object and its red shift, people thought these "galaxies" were actually nebulas and were within our own galaxy and that there was nothing beyond our own galaxy. In fact the word "nebula" was originally used to describe these mysterious objects. It was not until later that the word nebula was used to describe the remnants of an exploded star.
Unless you can measure how far away an object is, you cannot determine how large it is. The further away an object is the smaller it appears, however there are some small objects near by, so we need a more reliable way of measuring distance.
There are basically two ways to measure long distances:
Cepheid Variable stars are a special kind of star in that their hydrogen fuel has run out and they have begun to flicker from bright to dim over a few days. The bright phase is always twice as bright as their dim phase. This is a well known and proven fact. With this information one can measure how far away a Cepheid Variable is by how bright and dim the cycle comparison is. This technique is reliable up to 20 million light years.
There are quite a few galaxies that are within 20 million light years from earth (The nearest is Andromeda at only 2.2 million light years) and we know this because we can observe the Cepheid Variable stars within them and accurately measure their distance.
What is interesting is that we can also measure the red shift, and guess what? The red shift gives us a distance that is essentially the same as the distance calculated with the Cepheid Variables. This is how we can confirm that the red shift gives us an accurate measurement for distance.
Hey there Danny and Elsewhere, don't stop now. I'm quite enjoying your back and forth tete-a-tete.
Meanwhile Else, I have been trying to identify and gather information on the galaxy image you supplied. I have to agree with Danny that the picture is that of NGC-4565 (M145).
For the general readership here, this spiral galaxy is known as the Needle Galaxy in the constellation Coma Berenices (Bernice's Hair). It was discovered by William Herschel in 1785, and is one of the 200 brightest galaxies, and lies in and around the Virgo Supercluster. It has a distance of some 30 million light years, and a diameter of 100,000 light years across. It is perhaps the most famous example of an edge-on spiral galaxy. There is a massive intricate dust lane that bisects the galaxy into top and bottom halves, and this is quite common for spiral galaxies. This galaxy is regarded as quite similar to our own Milky Way.
I was not successful in identifying the points of light surrounding the primary object, and therefore could not comment on their respective distances either. I looked at literally dozens of sites to find such info and nothing shed any light on this. Perhaps you could enlighten me and the rest of us.
Anyways guys, I think that the Cepheid Variable Stars data corroborating the calculations for Redshift is the kind of thing I am looking for to test the other thesis of the observational quasars being in front of certain proximate galaxies. Even so, I would still be looking for an explanation as to how you could have a Quasar in front of a Galaxy with a higher redshift. To me that simply defies explanation when relying on the Redshift = Distance axiom.
Danny, if you look to Velocity (Redshift) as an explanation, are you suggesting that if a quasar appears to be in front of a galaxy (nearer), and the galaxy has a lesser redshift, that therefore it is because the galaxy is travelling at a lesser velocity away from us, and so we get this lower reading? And therefore, the implication is that the quasar could still be farther away?? Please clarify what you are suggesting.
Rod P.
Here is another rather current article about the problem of redshift in cosmology.
Rod P.
January 10, 2005
Discovery By UCSD Astronomers Poses A Cosmic Puzzle:
Can A 'Distant' Quasar Lie Within A Nearby Galaxy?
By Kim McDonald An international team of astronomers has discovered within the heart of a nearby spiral galaxy a quasar whose light spectrum indicates that it is billions of light years away. The finding poses a cosmic puzzle: How could a galaxy 300 million light years away contain a stellar object several billion light years away?
The team’s findings, which were presented today in San Diego at the January meeting of the American Astronomical Society and which will appear in the February 10 issue of the Astrophysical Journal, raise a fundamental problem for astronomers who had long assumed that the “high redshifts” in the light spectra of quasars meant these objects were among the fastest receding objects in the universe and, therefore, billions of light years away.
“Most people have wanted to argue that quasars are right at the edge of the universe,” said Geoffrey Burbidge, a professor of physics and astronomer at the University of California at San Diego’s Center for Astrophysics and Space Sciences and a member of the team. “But too many of them are being found closely associated with nearby, active galaxies for this to be accidental. If this quasar is physically associated with this galaxy, it must be close by.”
Astronomers generally estimate the distances to stellar objects by the speed with which they are receding from the earth. That recession velocity is calculated by measuring the amount the star’s light spectra is shifted to the lower frequency, or red end, of the light spectrum. This physical phenomenon, known as the Doppler Effect, can be experienced by someone standing near train tracks when the whistle or engine sounds from a moving train becomes lower in pitch, or sound frequency, as the train travels past.
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| Photo of nearby spiral galaxy NGC 7319 with high red-shift quasar at arrow (below). Credit: NASA/Hubble Space Telescope |
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Astronomers have used redshifts and the known brightness of stars as fundamental yardsticks to measure the distances to stars and galaxies. However, Burbidge said they have been unable to account for the growing number of quasi-stellar objects, or quasars—intense concentrations of energy believed to be produced by the swirling gas and dust surrounding massive black holes—with high redshifts that have been closely associated with nearby galaxies.
“If it weren’t for this redshift dilemma, astronomers would have thought quasars originated from these galaxies or were fired out from them like bullets or cannon balls,” he added.
The discovery reported by the team of astronomers, which includes his spouse, E. Margaret Burbidge, another noted astronomer and professor of physics at UCSD, is especially significant because it is the most extreme example of a quasar with a very large redshift in a nearby galaxy.
“No one has found a quasar with such a high redshift, with a redshift of 2.11, so close to the center of an active galaxy,” said Geoffrey Burbidge.
Margaret Burbidge, who reported the team’s finding at the meeting, said the quasar was first detected by the ROSAT X-ray satellite operated by the Max-Planck Institute for Astrophysics in Garching, Germany and found to be closely associated with the nucleus of the spiral galaxy NGC 7319. That galaxy is unusual because it lies in a group of interacting galaxies called Stephan’s Quintet.
Using a three-meter telescope operated by the University of California at Lick Observatory in the mountains above San Jose and the university’s 10-meter Keck I telescope on Mauna Kea in Hawaii, she and her team measured the redshifts of the spiral galaxy and quasar and found that the quasar appears to be interacting with the interstellar gas within the galaxy.
Because quasars and black holes are generally found within the most energetic parts of galaxies, their centers, the astronomers are further persuaded that this particular quasar resides within this spiral galaxy. Geoffrey Burbidge added that the fact that the quasar is so close to the center of this galaxy, only 8 arc seconds from the nucleus, and does not appear to be shrouded in any way by interstellar gas make it highly unlikely that the quasar lies far behind the galaxy, its light shining through the galaxy near its center by “an accident of projection.”
“If this quasar is close by, its redshift cannot be due to the expansion of the universe,” he adds. “If this is the case, this discovery casts doubt on the whole idea that quasars are very far away and can be used to do cosmology.”
Other members of the team, besides Geoffrey and Margaret Burbidge, included Vesa Junkkarinen, a research physicist at UCSD; Pasquale Galianni of the University of Lecce in Italy; and Halton Arp and Stefano Zibetti of the Max-Planck Institute for Astrophysics in Garching, Germany.
Comment: Geoffrey Burbidge, (858) 534-6626
Media Contact: Kim McDonald (858) 534-7572
Here's some food for thought on Cepheid Variables from "Big Bang Theory in Serious Trouble":
Cepheid Variables
A Cepheid variable is thought to be a “relatively young” star slightly larger than the sun whose luminosity changes in a periodic way. Scientific American 11/92, p. 56
Some difficulties with measuring velocities and distances
In principle, determining the value of the H.C. is rather simple, “requiring only a measurement of distance and velocity.” p.56
“Although measuring the velocity of a galaxy is straightforward, gauging the distance is rather difficult.” p.56
It should be mentioned here that the “straightforward” method used to determine a galaxy’s velocity is its red shift. p.56
“To obtain the velocity, astronomers disperse the light” (from that galaxy), “and
record its spectrum... For a galaxy moving away from the earth, the positions of
these spectral lines are shifted to longer wavelengths by an amount proportional
to the velocity--an effect known as the red shift.” p. 56
“To determine the distance to a galaxy, astronomers have a variety of complicated
methods. Each has its advantages, but none, it seems is perfect.”
One of these is the use of Cepheid variables. These are stars that vary in brightness over a given period. It has also believed that: “the distance to a Cepheid can be calculated from its period (the lenght of its cycle) and its average apparent brightness (its luminosity as observed from earth).” p. 56
Problems with using Cepheid variables to calculate distances:
1) Their luminosity can be diminished by dust between stars. p. 56-57
To compensate for this “astronomers either observe...(them) at infrared wavelengths where the effects are less significant,” or they “observe them at many different wavelengths so they can assess the effects and correct for them.” p. 57
Unfortunately “...Cepheids are bright enough to be observed only in the nearest galaxies, not the distant ones. And although nearby galaxies are” (so we are told) “participating in the expansion of the universe, the gravitational interactions among the neighbors may be causing some to move much faster or slower than the rest of the universe” (except of course the HUGE CHUNK--of which we are a part of-- that is moving in the direction of Virgo) “consequently to calculate the Hubble Constant, astronomers must accurately determine the distances to remote galaxies, and the task is extremely difficult.” p.57 Emphasis added
Translation: Although Cepheids are what we use as a standard candle to measure distances, they really are not very useful in determining whether or not the universe is expanding (or at what rate) because to do this, we must accurately determine the distances to far off galaxies. And even though Cepheids are what we use to do this, we can’t do it very accurately because Cepheids are only useful in nearby galaxies.
Do you see what I am getting at?
“Nevertheless, astronomers have developed several methods for determining distances to remote galaxies.”
But “Because many of these techniques must be calibrated using the Cepheid distance scale” they are considered secondary distance indicators...Yet scientists cannot reach a consensus about which, if any, secondary indicators are reliable.” p. 57
I first want to explain a bit more about the distance calculations in the universe. Then I will respond to some of the post above.
Anyway there are more then only the cepheid variable stars.
We do know the distances in our solar system very well. We know the mass, distance, rotation time etc. (we can send space crafts exactly)
This is a base for measuring stars that are not to far away. We can observe the paralax of the star when the earth in on one side of the sun, and then the other. (for example on jan and july). With simple math we can then calculate the distance.
There was also a satellite who did this more accurately and messured 1 million stars.
When you know the distance, you know the absolute brightness. This helped to classify the stars in groups, because we can also messure the temperature of the star directly.
It turned out there is a relation between temperature and brightness. The Hertzsprung russell diagram. Stars are placed in different catagories, OBAFGKM (we could easy remember this with the line "O Be A Fine Girl Kiss Me").
My measuring the temperature we can thus also estimate the distance.
Then there were the variable stars. The already mentioned Cepheid stars. But also the LL Lyrae stars.
There are other methods which can be used only in certain cases but they can all be used to check and calibrate the distances.
For example the Baade Wesseling Method. having to do with color and light flux curves.
With spectroscopy we can not only find the temperature and chemical composition of a star but we can also say something about the gravity at the stars surface. This can also be used to calculate the distance.
There are binary stars, for some we can calculate the orbit and compare it to the visual orbit, and so calculate the distance.
Then we can know the motion of certain stars, and can fit that with there position in the milky way, as all stars radial motion, circling around teh center.
There are some additional methods also for calculating distances to nebulas etc.
So we know the distances in our galaxy reasonably well. Now other galaxies:
We have the following methods:
We can find LL Lyrae stars and Cypheid stars in other galaxies, and thus calculate the distance. (only closer galaxies)
There seems to be a limit to the size of a star, so to find the brighests stars in a galaxy we can estimate its distance.
There are supernova that have a predictable absolute brightness. Called type 1a supernova. We can measure the brightness and thus estimate the distance. (they are events, so you have to be lucky)
We can measure the rotation of a galaxy, (by spectroscopy). There is a relation between rotation and luminosity.
Then there is a gravitational lens time delay. Consider a massive invisible object in path of sight of a farther brighter object. The light will bend around the object, giving multiple images of the object. It will take the light longer on different paths. In some cases the time delay can be measured and thus the distance calculated. (I have personally done some research on gravitational lenses, but not time delay).
Oh yeah, and then there is the red-shift.
There are still more methods. So it is not just one. Some are not very accurate, but all give indication that things are not totally wrong.
Hope this helps, to understand the issue is a bit more complex then assumed in the articles of the original post.
Danny
Elsewhere,
Ok, I'll get to my point.
Until Hubble discovered the relationship between the distance of an object and its red shift, people thought these "galaxies" were actually nebulas and were within our own galaxy and that there was nothing beyond our own galaxy. In fact the word "nebula" was originally used to describe these mysterious objects. It was not until later that the word nebula was used to describe the remnants of an exploded star.
Correct. At first they had of course no notion of how our own galxy looked like, or in fact that there were galaxis at all.
Unless you can measure how far away an object is, you cannot determine how large it is. The further away an object is the smaller it appears, however there are some small objects near by, so we need a more reliable way of measuring distance.
There are some cases where the size of a object can be measured without knowing the distance. For example in some real nebulas, we can observe the expansion rate (take picture now, and 20 years later), and we can also see know the speed of the expansion by spectroscopy. So the real size is known first. The distance follows then from the visible size.
There are basically two ways to measure long distances:
- Cepheid Variable stars
- The Red Shift
There are more ways. See my post above.
Cepheid Variable stars are a special kind of star in that their hydrogen fuel has run out and they have begun to flicker from bright to dim over a few days. The bright phase is always twice as bright as their dim phase. This is a well known and proven fact. With this information one can measure how far away a Cepheid Variable is by how bright and dim the cycle comparison is. This technique is reliable up to 20 million light years.
yes, you have to be able to view individual Cepheid stars, hence the limit in distance.
There are quite a few galaxies that are within 20 million light years from earth (The nearest is Andromeda at only 2.2 million light years) and we know this because we can observe the Cepheid Variable stars within them and accurately measure their distance.
What is interesting is that we can also measure the red shift, and guess what? The red shift gives us a distance that is essentially the same as the distance calculated with the Cepheid Variables. This is how we can confirm that the red shift gives us an accurate measurement for distance.
yes correct. However the is a constant between red shift and distance, called the hubble constant. This constant was unknown, so the Cepheid stars were used to calculate this constant. But the relation between distance and red-shift was constant, and that was a good confirmation.
Danny
