FAR OUT: An ultra-deep Hubble Space Telescope image has produced a compelling candidate for the most distant galaxy ever discovered.
Image: NASA, ESA, Garth Illingworth (University of California, Santa Cruz) and Rychard Bouwens (University of California, Santa Cruz and Leiden University) and the HUDF09 Team
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It was a long time ago, and it was a galaxy far, far away, but it's doubtful that any Ewoks, Hutts or Wookies would have had time to evolve there. In fact, the galaxy in question is so far away, and the distance its light must travel to reach Earth so vast, that astronomers see the galaxy as it appeared more than 13 billion years ago, when the universe was just 3 or 4 percent its present age.
The galaxy, which goes by the prosaic name of UDFj-39546284, has just been located in a long-exposure image of the Hubble Space Telescope meant to identify just such faint, distant objects. The find has yet to be confirmed with other observations, but if it stands up, the galaxy would be the most distant object ever identified. A team of U.S.- and Europe-based researchers announced the discovery in the January 27 issue of Nature. (Scientific American is part of Nature Publishing Group.)
When dealing with exceedingly distant cosmological objects, astronomers rely on a measure known as redshift, which quantifies how much an object's emitted light has been stretched to longer, or redder, wavelengths as the object recedes away from us in an expanding universe. Thanks to a 2009 upgrade by NASA astronauts, who delivered a powerful new camera to Hubble, the orbiting observatory has been reaching back to redshifts never before observed. In October a group of researchers announced that they had used a long-exposure Hubble campaign, known as the Hubble Ultra-Deep Field 2009 (HUDF09), along with a ground-based telescope to confirm the presence of a galaxy at redshift 8.55, about 600 million years after the big bang. The newfound galaxy UDFj-39546284, also from HUDF09, has a redshift of approximately 10, placing it about 100 million years closer to the dawn of the universe.
"You're essentially reaching back something like 97 percent of cosmic time, back to the very beginning," says astronomer Rychard Bouwens of Leiden University in the Netherlands, the first author of the new paper. One of the most remarkable features of Hubble's recent finds is that they are dim, somewhat humdrum galaxies, not luminous cosmic beacons such as quasars or gamma-ray bursts, which used to dominate high-redshift astronomy.
The combination of Hubble's perch above the shroud of Earth's atmosphere, the space observatory's new instruments, and its repeated pointing at the same patch for dozens and dozens of hours allowed the researchers to identify the faint smudge of a galaxy. Bouwens and his colleagues used the common technique of looking at an object with a number of wavelength-specific filters to find the point at which the object disappears from Hubble's imagery. If the dropout comes from neutral hydrogen between galaxies absorbing the light before it reaches Earth, researchers can use the known absorption property of hydrogen to infer the object's redshift.
But UDFj-39546284 appears in only one wavelength band, and verifying the galaxy's presence with another observatory may prove impossible until Hubble's successor, the James Webb Space Telescope (JWST), takes flight later in the decade. The researchers calculated that there is a 20 percent chance that the galaxy is not what it seems, an estimate that Bouwens calls "super conservative." UDFj-39546284 could be nothing at all—a mere glitch in the data—or it could be a nearby object masquerading as a distant galaxy. "The source is faint enough that we don't have a crystal-clear spectrum, so a lower-redshift object could look kind of like this candidate if there was a conspiracy in the noise," Bouwens says. "We're pushing the limits, and we're trying to do the best we can," he adds. "From my experience in doing this procedure it looks like this one could be the real thing."
Whether the galaxy proves to be real or not, Bouwens and his colleagues used the relative dearth of visible galaxies found in the HUDF09 at redshift 10 to set some limits on galactic luminosity and rates of star formation at that epoch, important markers of how the universe was developing. For if there were a plethora of bright galaxies 500 million years after the big bang, Hubble should have seen more of them. "Astronomers are often involved in these fishing expeditions, and this is the first time that we thought it might yield some fish," Bouwens says. "That's why the upper limit is meaningful."
The group found that the universe was in the midst of major changes at that time: There was a huge build-up of galaxies and a tenfold boost in star formation rates between redshift 10 and redshift 8, less than 200 million years later. But the rapidity of change raises an eyebrow for Matthew Lehnert of the Paris Observatory, lead author of the October paper announcing the redshift 8.55 galaxy. "That's the blink of an eye, 100 million or 200 million years," Lehnert says. "To have a change that big in that short of time kind of worries me." Perhaps Hubble's field of view was simply a bit barren, Lehnert ventures—if a neighboring patch of the sky contained a few more galaxies at redshift 10, the observed evolution would look to be smoother.
In fact, an earlier version of Bouwens and his colleagues' paper based on a smaller set of Hubble data contained three possible high-redshift galaxies, but with the addition of more observations the new, more compelling candidate emerged. The appearance or disappearance of plausible objects over time "just tells you how difficult it is when you have low signal to noise," Lehnert says, adding that Bouwens and his colleagues have made a reasonable case for the newfound galaxy. "These are really good researchers," Lehnert says. "Rychard really is the guy that does this kind of work."
As redshifts inch ever higher, astronomers are approaching the limits of how far back the current generation of telescopes can reach. "This is one of the deepest images ever taken, and they only have one good candidate, so you can see that we're sort of against the wall," Lehnert says. That only raises the anticipation for JWST, which a congressionally requested analysis recently found to be over-budget and behind schedule. The telescope will not launch before 2015 under the best of circumstances, the report concluded, and the actual launch date could be much later than that.
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51 Comments
Add CommentIf the distance/emission age of this galaxy has been derived from redshift using standard cosmological models, and distances derived from high-z type Ia supernovae luminosities have indicated that distant objects are actually much more distance than their host galaxies' redshift indicates (seemingly implying the acceleration of universal expansion and dark energy), it seems that this galaxy could be more than 13.2Glya, if its distance could be determined from an SN Ia observation. Something does not compute here...
Reply | Report Abuse | Link to thisIn searching for these very distant objects, there must come a point at which nothing more distant can be seen because their light has not yet had time to reach Earth.
Reply | Report Abuse | Link to thisIs it possible to look back as far as the Big Bang? Or will our species be extinct before the light reaches us?
Anything that distant must have emitted its observable light so long ago that the universe could not have been very old. That's why this article's opening paragraph states:
Reply | Report Abuse | Link to this"In fact, the galaxy in question is so far away, and the distance its light must travel to reach Earth so vast, that astronomers see the galaxy as it appeared more than 13 billion years ago, when the universe was just 3 or 4 percent its present age."
Presuming that no light that is observable within the universe could have been emitted outside the universe, before the big bang or even before some initial development of the universe following the initiation event, all extragalactic objects that we observe emitted their detected light when the universe was proportionally younger. I suggest the following free sources:
http://en.wikipedia.org/wiki/Big_bang_theory
http://en.wikipedia.org/wiki/Observable_universe
http://commons.wikimedia.org/wiki/File:CMB_Timeline300_no_WMAP.jpg
I find the improved telescopic technology and methodologies for peering into the cosmos to be truely amazing. I still have difficulty, however, accepting conclusions as to age or distance based on red shift. I think it would be prudent to just state the ranges of red shift being observed and leave it at that. Isn't that interesting enough? I think anything beyond that remains speculation until we have a fuller understanding of what "time" is and what the shape of the universe is, and how light behaves through it.
Reply | Report Abuse | Link to thisAre these ages calculated under the assumption that red shift is constant?
Reply | Report Abuse | Link to thisCan I assume that by looking in the direction of this newly found object we are roughly looking in the direction of the point in space where the big bang actually occurred?
Reply | Report Abuse | Link to thisPresumably the inflation stage expanded the universe to a size that it appears flat. This is like saying that what is visible to us is comparable to a small enough area of the surface of the earth that it has no detectable curvature. Thus the universe is much larger than it appears, yet is only 13.7 billion years old. The problem with this is that it would have distributed the energy from the singularity out very smoothly, which is why Inflation was first proposed. Now the explanation for how a galaxy large enough to be seen across 13.2 billion lightyears could have coalesced in 500 million years, is dark matter. Wouldn't dark matter have been equally distributed, since its primary characteristic is gravitation and it's the balance of gravity to expansion which causes space to appear flat? How did that much dark matter come together so quickly?
Reply | Report Abuse | Link to thisKeep in mind that it takes our Milky Way galaxy 225 million years to make one rotation, so the argument here is that in an amount of time our galaxy makes two and a half rotations, this one coalesced out of the primordial radiation, with dark matter as the attractor. I think our current cosmology is about to founder on the rock of contradictory observation, when they discover another galaxy 500 million years older.
http://www.americanscientist.org/issues/pub/2007/9/modern-cosmology-science-or-folktale
As large as the universe is, as small as we are, will we survive the environmental change. What if we are as rare as we seem to find ourselves to be? Evolution seems to work only rarely and with a lot of time. Oh well if we are not here who will miss us?
Reply | Report Abuse | Link to thisThe oldest light that has been and that can be detected is the cosmic microwave background (CMB). We cannot see it with our eyes or optical telescopes and it can only be detected via radio telescopes. It was emitted at the time of the last scattering of photons within the clogged up primal cloud of particles. WMAP scientist date the CMB or earliest light to about 380,000 years after the Big Bang. We cannot in principle detect any "light" older than the CMB. This means from our perspective the universe prior to this point was electromagnetically dark. However this was long before any stars or galaxies appeared. It means that we could (given sensitive enough receptors) be able to detect the light from any early galaxy.
Reply | Report Abuse | Link to thisThere is the possibility of detecting gravitational waves or neutrinos behind the CMB curtain and therefore closer to the time of the Big Bang. However we do not currently have the technology but research continues.
see http://antspub.com
Red shift cannot really be said to be constant. It is a measurement of how much celestial light (emitted by an element in outer space) has been stretched compared to the same element's emission (light signature) on earth.
Reply | Report Abuse | Link to thisThe expansion of space/time is the reason why light stretches on its journey to our detectors. We have good reason to think the expansion rate of our universe has varied over time. Studies of type 1a supernovae indicate our universe's expansion rate has been accelerating for the past 5 billion or so years.
The red shift numbers cited e.g. 1 to 10 are indicators of distances from earth to the source emission.
see http://antspub.com
You cannot disconnect the red shift numbers (e.g. 1 to 10) from the distance of earth to the source element's emission. The logic of your point is like saying we should not use "miles" as distant indicators between cities. Further the red shift numbers do not have anything to do with what "time" is or the shape of the universe.
Reply | Report Abuse | Link to thissee http://antspub.com
The big bang wasn't an explosion in space/time; it was the creation/expansion of space/time and forces/mass within it. This means the big bang didn't occur at any location within space/time. However the further away our detections take us the closer we get to the time of the genesis or big bang.
Reply | Report Abuse | Link to thissee http://antspub.com
Not to argue, but I'm curious as to how it could be determined that any detected neutrinos or (hypothetical) gravitational waves had been emitted prior the CMB emissions?
Reply | Report Abuse | Link to thisRe: "Studies of type 1a supernovae indicate our universe's expansion rate has been accelerating for the past 5 billion or so years."
Reply | Report Abuse | Link to thisAs I understand, the distance estimates for consistent luminosity type Ia SNe clustered around 5Glya agreed with the distance predictions of standard cosmological models based on the redshift of the SNe host galaxies' light.
However, the luminosity based distance estimates for more distant (~10Glya) type Ia SNe significantly exceeded the distance estimates based on the redshift their host galaxies' light.
If I understand correctly, a negative value for the cosmological constant parameter was used to compensate for this discrepancy, allowing the cosmological models to agree with the luminosity based distance estimates. Using some line of reasoning I apparently can't understand, the researchers concluded from these results that the expansion of the universe had begun accelerating sometime between about 5-10 billion years ago.
I can only interpret their result to indicate that the ancient light emissions from more distant galaxies had traversed spacetime that had been expanded at a greater rate than had the more recent light emissions from nearer galaxies.
Perhaps you can explain my error?
I should have mentioned that my interpretation indicates that the expansion of the universe has decelerated during the past 5 billion years, compared to the preceding 5 billion years, consistent the second law of thermodynamics. I really can't understand how the researchers concluded otherwise - any help you can provide would be appreciated. Thanks in advance.
Reply | Report Abuse | Link to thisThis might sound a little strange, but then Dark Energy sure sounded strange when first postulated. We measure distances based on red shifts, assuming that the shift comes only from the Doppler Effect. When light travels over such vast distances, is it possible that there is something else that shifts the spectrum toward red? Could empty space have something similar to an "index of refraction" that preserves shapes and relative spacing of spectral lines but shifts light toward the red? This would be impossible to measure in the lab because of the vast distances needed.
Reply | Report Abuse | Link to thisIt's called cosmological redshift. Please see:
Reply | Report Abuse | Link to thishttp://en.wikipedia.org/wiki/Hubble's_law
I understand that. The question remains: could there be a weak phenomenon other than Doppler that at very long distances shifts light to the red? The Standard Model uses Dark Energy to explain the red shifts of distant galaxies. However, Dark Energy still remains a hypothesis that is used to explain the shifts. This cannot be measured in a lab, and there is not much of a solid theoretical basis for its existence and nature. It’s essentially a “fudge factor”, not unknown in Cosmology. So why not think about another possibility. How about another hypothesis that there is something like an "index of refraction" that shifts light to the red. Anyway, this is just a thought approaching things from a different direction……
Reply | Report Abuse | Link to thisThe early universe was very hot and largely acted like a nuclear fusion reactor. Some light elements were created via nuclear fusion such as helium. Stars like our Sun depend on fusion reactions and we know that neutrinos are emitted in the process. Millions of them are passing through your body as you read this. It is clear that the early universe also must have generated an enormous number of neutrinos. The problem is that neutrinos only interact via gravity and the weak nuclear force and are therefore very difficult to detect. However in principle, at least, it is possible to detect these early neutrinos and generate early maps that may be similar to those generated by the CMB data. If so the early neutrinos would allow us to peak further back in time.
Reply | Report Abuse | Link to thisEinstein predicted the existence of gravitational waves (GWs) and if they exist they should be everywhere. We have yet to directly detect a GW but there are on-going experiments. Strong GWs should be emitted around sudden fluxes/changes around high mass/energy systems such as binary stars and black holes. It follows that the early universe should have emitted very powerful GWS due to all of the high energy fluxes and changes. We may eventually succeed in detecting GWs from behind the CMB curtain and perhaps all the way back the genesis.
Sorry - I misunderstood.
Reply | Report Abuse | Link to thisAs I understand, the higer-z SNe luminosity more directly indicated distances beyond the predictions based on redshift: the proportionality of redshift to distance for objects <5Glya was too low to account for the 'actual' distance determined by the type Ia SNe 'standard candles'.
In that case, I think we should be trying to understand how light could have traversed spacetime without being redshifted.
IMO, if cosmological redshift is imparted to the wavelength of light by the accumulation of its physical extension produced by spacetime expansion, perhaps in some conditions of obtuse propagation angles (relative to predominant local expansion direction) and extreme expansion rates, light traversing expanding spacetime in the dense early universe was directionally curved rather than having its wavelength linearly extended.
This would not be consistent with many precepts of astrophysics, but then the established interpretation of results (the acceleration of expansion) is inconsistent with the second law of thermodynamics, requiring some unspecified, unidentified form of dark energy. It seems to me that the the more extraordinary proof should be demanded of the already established interpretation!
Thanks, but how can we determine that any detected neutrinos or gravitational waves were produced in the conditions of the very early universe rather than by more recent events? Unlike EM emissions, there'd be no spectrum to redshift, calibrated to the elementary emission spectra, correct?
Reply | Report Abuse | Link to thisSorry, kenkoskinen - I think the answer to my question just occurred to me. In addition to its microwave detected frequency (generally consistent with a redshifted infrared emission frequency), the CMB was identified by its faint isotropic detection throughout the sky, indicating its emission source was universal.
Reply | Report Abuse | Link to thisI guess that any similarly isotropic detection of neutrinos or gravity waves could be reasonably assumed to have a universal origin.
However, the detection of microwaves did not present the technical challenge of detecting a sufficient quantity of neutrinos or apparently gravity waves to establish an universally isotropic distribution.
I agree that such detections would be extremely enlightening, but without some enormous breakthrough in detection technology I'm afraid it's pretty wishful thinking. Thanks.
In the late 1990's two separate groups of researchers concluded that the rate of the universe's expansion is and has been accelerating. This result was the opposite of what they and other scientists believed. The acceleration of the universe was supposed to be slowing down. However, the evidence and reasons are complex but dove tail with several and very different cosmological fields of study. For example: the CMB data combined with the measured Hubble constant confirm the supernova data: there is a positive but small vacuum energy density. However note the "pressure" of a positive cosmological constant is negative and hence acts like anti-gravity.
Reply | Report Abuse | Link to thisLet me refer to Robert P. Krishner's book "The Extravagant Universe: Exploding Stars, Dark Energy and the Accelerating Cosmos." Krishner was in the thick of the leading edge of research and relates the story of the surprising discovery in detail. It is worth while revealing read.
Keep in mind that science proceeds by the discovery of "what" happens before the "how & why" questions are answered. Although we don't know the "how & why" of Dark Energy the idea the universe's expansion is accelerating is based on very good research. (See my other comments).
Reply | Report Abuse | Link to thisNewton only gave us the "what" happens about gravity in his theory of gravitation. Einstein's general theory of relativity i.e. his theory of gravity gives us a more complete "what happens" but doesn't do any better on the "how & why" questions. We expect to get these answers after someone succeeds in developing a theory of quantum gravity. Even though our understanding of gravity isn't complete we don't discard these well tested theories. Knowing part of the truth is better than not knowing anything. The study of Dark Energy is in its infancy but it also appears to be part of cosmological reality.
Inflation was grafted into the original big bang theory to explain the matter distribution mystery. However, it hasn't been proven and other mechanisms might have accomplished the same result without the mind boggling rapid expansion. No satisfactory explanation as per what could have caused inflation has ever been tabled. Even dark energy that is and has been fueling the acceleration of the expansion of the universe is many orders of magnitude lower than the so-called inflation mechanism.
Reply | Report Abuse | Link to thisThere also isn't any reason to think dark matter is as evenly distributed as visible or baryonic matter is. Baryonic matter is only evenly distributed on the large scale and hence forms lumps that we call galaxies and galaxy clusters. The majority of space/time consists of practically empty voids.
Several studies show dark matter forms haloes around galaxies and clusters. The implication is dark matter gets attracted to baryonic matter but probably does so selectively based on local conditions. I suspect dark matter doesn't cling to high areas of baryonic matter such as around inner galaxy black holes but is more attracted to areas where the quantity of baryonic matter drops off. For example, it keeps the outer galaxy stars in orbit within the galaxies. These areas are relatively sparse in baryonic matter content.
Considering the above, there shouldn't be any problem of dark matter's aiding role in early galaxy formation. See http://antspub.com
If dark energy is a force that became influential enough about 5 billion years ago to cause an increase in the rate of expansion it doesn't conflict with the 2nd law of thermodynamics. I don't mean to sound pedantic but the entropy law only applies to closed systems. Life, for example,evolved on earth but the uphill climb was paid for primarily by solar energy. If energy is inputted into a system its open and entropy has to wait for its turn to cause the downhill slide. Whether dark energy will ever dissipate is unknown.
Reply | Report Abuse | Link to thisDoesn't that argument requires that dark energy be interjected from outside the universe around 5 billion years ago?
Reply | Report Abuse | Link to thisRe.: "Several studies show dark matter forms haloes around galaxies and clusters."
Reply | Report Abuse | Link to thisAs I understand, if any dark matter were present among the observed baryonic matter, within the prescribed halo, additional dark matter would be required in the spherical halo to simulate the observed gravitational effects. The spherical dark matter halo idea is simply the configuration of compensatory mass necessary to produce the flat rotational curve out to the distances at which it's observed in spiral galaxies, applying Kepler's empirically derived laws of Planetary Motion to galaxies. In all cases, however, galaxies are not planetary systems.
No, the mass of planetary systems is almost exclusively centrally configured. 99.86% of all mass within the Solar system is contained within the Sun, for example. The mass of galaxies, particularly planar spiral galaxies, is exceedingly disperse, distributed among up to hundreds of billions of discrete objects of distances spanning many tens of thousands of light years. The overly simplified methods of gravitational evaluation that yield adequate results for the centralized mass configurations of planetary systems are not appropriate for galaxies. Please refer to: "General relativistic dynamics applied to the rotation curves of galaxies"; http://arxiv.org/abs/1101.3224 for an appropriate method of galactic gravitational evaluation.
No. Dark energy, regardless of what is causing it, is cosmological/universal and therefore cannot be interjected from outside. Its influence builds over time. Some models have it eventually running amok and causing what is termed "the big rip." It does not fall within the control range of the 2nd law.
Reply | Report Abuse | Link to thisVisible matter and central black holes are sufficient to account for inner galactic activity. So, you're right about most mass being centrally located. The early mystery was and still is what is causing outer stars to stay in orbit within their galaxies. Something is accelerating these stars as they continue in orbit. If dark matter is the cause some of it must be bolstering the sparser mass on the outskirts of galaxies. However, this doesn't mean dark matter is "only" on the outskirts of galaxies.
Reply | Report Abuse | Link to thisSeveral studies using stellar motions and/or gravitational lensing have produced simulated dark matter photos. For one example see:
http://news.nationalgeographic.com/news/2007/05/070515-dark-matter.html
You seem to have misunderstood: the centralized mass model applies to planetary systems, not at all to spiral galaxies. I strongly recommend that you refer to: "General relativistic dynamics applied to the rotation curves of galaxies";
Reply | Report Abuse | Link to thishttp://arxiv.org/abs/1101.3224
I tried unsuccessfully to download it, so I couldn't read it. Please email me a copy at: kenkoskinen@yahoo.com.
Reply | Report Abuse | Link to thisKeep in mind that not all galaxies are spiral, they are also elliptical and irregular etc. Dark matter models are still viable and whatever it is it does interact with baryonic matter. Of course there is the Modified Newtonian Dynamics (MOND) theory but it is still on the fringe. It has some hits via detections but others are off or questionable.
The key may not be the presence or density of visible matter as I earlier alluded but rather their associated accelerations. There are several gravity anomalies which I think also speak to the need for dark matter interacting with accelerating baryonic matter such as: the pioneer anomaly, near earth satellite fly byes and discrepancies in the Earth-Moon system as per Newtonian and relativistic gravitational models. The later speaks to discrepancies via the on-going Lunar Laser Ranging Experiment. It continually measures the distance between the earth and moon via reflectors placed on the moon by Apollo moon walkers. A few years back I was in email contact with the project manager and he related there are discrepancies between the measured results and those predict by gravitational theories. Something does add up and I think a dark matter interaction with baryonic matter in motion may be the solution.
I have a bit of a stupid question. I have heard that the more distant a galaxy is from us the faster it is moving away from us. If the light that we can see from distant galaxies is billions of years older than the light that we can see from closer galaxies than why does this not mean that the expansion of the universe is slowing down and not speeding up?
Reply | Report Abuse | Link to thisRe:I have a bit of a stupid question. I have heard that the more distant a galaxy is from us the faster it is moving away from us. If the light that we can see from distant galaxies is billions of years older than the light that we can see from closer galaxies than why does this not mean that the expansion of the universe is slowing down and not speeding up?
Reply | Report Abuse | Link to thisYes, Hubble's Law is the basis of what you have heard. The issue about the expansion of our universe is that studies since the late 1990's show the rate of expansion has been accelerating over the last 5 billion or so years. Prior to this it was widely believed the rate should be decelerating due the braking effect of the universe's collective gravity. Something must be causing the increase in the rate and it has been dubbed "Dark Energy."
The mere comparison of light from differing distant galaxies is independent of the increase in the rate of acceleration unless a galaxy is beyond the point where the acceleration rate increases. In this case the light would be more stretched or red shifted during the rest of its journey to our detectors (on or in orbit around Earth). The reason the light stretches more is because the space/time it travels through expands more i.e due to the increased rate of expansion.
Type 1a supernovae were the standard candles used to discover dark energy. They were idea since these explosions have a known luminosity. If we both have the same kind of flash light and we walk away from each other, the further apart we are the dimmer the light becomes. If we know our distance from each other we could predict the luminosity of our flash lights. Well, a number of type 1a supernovae appeared to dimmer than expected and so after numerous checks for errors it was concluded the expected distances were greater. It meant the space/time had been expanding at an increased rate. It was quite a surprise and discovered by two independent groups of research scientists. Since then more research has bolstered the original studies including that from other independent cosmological fields of study.
Simply put: If as you suggest the universe's rate of expansion was decelerating the light from the type 1a supernovae in the studies should have appeared to have been brighter. However, it was dimmer than expected.
Yes, yes, the light from more distant galaxies was dimmer, indicating that they were further away than their redshifts indicated: "The distances of the high-redshift SNe Ia are, on average, 10% to 15% farther than expected..." Please refer to "Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant";
Reply | Report Abuse | Link to thishttp://arxiv.org/abs/astro-ph/9805201v1
Now then, why is the anomalous relationship between redshift and distance for the more distant objects observed considered to indicate the acceleration of universal expansion? The more ancient emission of light from more distant galaxies indicate increased expansion - of the earlier universe...
You state the established interpretation:
Reply | Report Abuse | Link to this"The mere comparison of light from differing distant galaxies is independent of the increase in the rate of acceleration unless a galaxy is beyond the point where the acceleration rate increases. In this case the light would be more stretched or red shifted during the rest of its journey to our detectors (on or in orbit around Earth). The reason the light stretches more is because the space/time it travels through expands more i.e due to the increased rate of expansion."
Thank you! Now, please consider that the increased rate of expansion does not occur at a specific distance from the Earth, but rather the increased rate of expansion was effective for a specific period of time, as the universe developed.
Consider that the light observed from more distance galaxies had to traverse the conditions of the universe that were prevalent at an earlier time, for example, 10 billion years ago. If the light from more distant galaxies indicates that spacetime expansion was greater than does light emitted 5 billion years ago, it is because the rate of expansion between 5 and 10 billion years ago was greater that it has been for the past 5 billion years.
Light from both the near and distant galaxies traversed the same conditions of spacetime expansion that have existed for the past 5 billion years. Only the light from more distant galaxies had to traverse the conditions of expansion that existed from 5-10 billion years ago.
If the more ancient light from more distant galaxies indicates greater expansion than does the more recent light from nearer galaxies, it can only mean that the expansion of the universe has diminished in time.
Anyone, please let me know if this simple reasoning is in any way incorrect.
Re:If the more ancient light from more distant galaxies indicates greater expansion than does the more recent light from nearer galaxies, it can only mean that the expansion of the universe has diminished in time.
Reply | Report Abuse | Link to thisAnyone, please let me know if this simple reasoning is in any way incorrect.
jtdwyer, you are right. When I wrote "point" I should have written "point in time." The flaw in your argument is the following. You have neglected to consider the universe has always been expanding. Hence any older light is always more red shifted or stretched compared to younger light (i.e. both have to be of similar elemental origin or process to make the comparison). This is true independent of whether the universe's rate of expansion at any point in time began to accelerate or not. The discovery of dark energy only means that the ancient light is even more red shifted when we detect it. Again, to simply state it: the type 1a supernovae appear to be dimmer than expected and hence the rate of the universe's acceleration at some point started to accelerate.
To determine when that point in time occurred the science teams had to detect several type 1a supernovae in a sequence of time points. They have succeeded, and this also strengthened the case for dark energy.
I truly don't know where to begin to respond. Let me just say that if you were commenting on my most recent comment, I never referred to redshift at all. To avoid any confusion about redshifts, I simply stated:
Reply | Report Abuse | Link to this"If the light from more distant galaxies indicates that spacetime expansion was greater than does light emitted 5 billion years ago, it is because the rate of expansion between 5 and 10 billion years ago was greater that it has been for the past 5 billion years."
This description relies only on the astrophysicists determination of which observations indicated acceleration to them. That's enough.
Some basic questions from an amateur:
Reply | Report Abuse | Link to thisWhat's meant by "redshift 8.55"? Are wavelengths 8.55 times longer, or what?
Do we depend on one spectral hydrogen line to determine relative speed, distance and age? How do we know it's the assumed line? Shouldn't we be verifying it by finding several agreeing lines throughout the spectrum?
Is there nothing outside the Milky Way that shows a "blueshift", or redshift that doesn't fit with other data? Are the apparent relative velocities of all galaxies proven to be proportional to their distance, and by what means, beyond Cephid variables? Is the general expansion really that consistent?
I tend to think cosmology, quantum physics and such are based too much on long chains of assumptions and that specific phenomena try to show universal rules, though often the results don't make sense to our day to day senses.
Even if we get to seeing within seconds of the Big Bang, we're left with the question of what caused it. In religious (or anti-) terms, who created the creator? Why is there something rather than nothing? Are there perhaps an infinity other universes(?) where there is nothing? How do we know? Can we ever "know"? Is cosmology, the new theology, mostly fantasy?
Please send a copy of your answers to danrob@efn.org.
Re: jtdwyer: I truly don't know where to begin to respond. Let me just say that if you were commenting on my most recent comment, I never referred to redshift at all. To avoid any confusion about redshifts, I simply stated:
Reply | Report Abuse | Link to this"If the light from more distant galaxies indicates that spacetime expansion was greater than does light emitted 5 billion years ago, it is because the rate of expansion between 5 and 10 billion years ago was greater that it has been for the past 5 billion years."
This description relies only on the astrophysicists determination of which observations indicated acceleration to them. That's enough.
Cosmological redshift & space/time expansion refer to the same thing. You have it backwards. The rate of expansion increased at about the 5 billion year point. Therefore the "rate" of expansion was "lower" between the 10 billion and 5 billion year marks. Put simply: space/time has always been expanding it is simply that the rate of acceleration has increased around the 5 billion year. But yes older light can still be comparatively more redshifted than younger light. This follows since it has be subjected to more overall space/time expansion or cosmological red-shifting.
OMG, I wonder if these aliens we are suppose to see soon are from that distant place ???
Reply | Report Abuse | Link to thisDaniel35, there are different kinds of redshift. The one produced by the expansion of the universe is referred to as cosmological redshift. The expansion of space/time is the reason most galaxies in the universe have redshifts. It is important to note the expansion occurs between galaxies and clusters. There are some galaxies that are blue-shifted to the Milkway such as the fairly nearby Andromeda galaxy. These two galaxies interact gravitationally and are moving towards each other. In some billions of years they will merge and create a new galaxy. However, most galaxies are moving away from us, but this is not the main cause of their redshifts. Instead space/time expands between galaxies/clusters and stretches light waves. The farther a galaxy, the longer its light waves have traveled and the more they are redshifted.
Reply | Report Abuse | Link to thisThe spectral signature of hydrogen on earth is not redshifted. It is experimentally detected and not assumed. It and that of other elements have been catalogued and are used as a comparative base to that of the spectral signatures of light we detect from outer space. This is one way we can tell how much the celestial signatures have been cosmologically redshifted. This means the spectral lines have been stretched towards the red direction of the electromagnetic spectrum. The terms red & blue shouldn’t be taken too literally, since it refers to comparative stretching (red) or compressing (blue) of the light signature. The redshift “z” number such as 8.55 is without units and is a comparative measure of how much the spectral lines have been shifted towards the red (blue-shifted lines are represented by negative z numbers). The z number also acts roughly like a relative time scale. Generally, the larger the z number the greater is the cosmological redshift and the older is/was the emission source.
Hubble’s law is the mathematical formula that resulted from numerous observations of galactic velocities being proportional to distances. Standard candles are celestial objects that have a known luminosity and therefore can be used to determine astronomical distances. One type is Cepheid variables and another is type 1a supernovae. Each method has an optimal distance detecting range.
Scientific theories can include assumptions but, unlike theology, when possible these are tested via reason/logic, experiments and detections. Science is a human activity that grew as an objective means to understand natural phenomena. Scientists fought for the right to operate independently of the meddling and interference of the church. It isn’t theology, and doesn’t really say anything about an assumed God. The scientific quest includes developing theories that best explain known observations/detections including those about the genesis of the universe. However, science doesn’t provide perfect answers or the ultimate truth. It proceeds by discovering the best approximations that can be found due to the preponderance of the evidence and/or beyond a reasonable doubt. Theories are subject to peer review and can be accepted, disproven or improved. Over time they can also be changed due to new detections or interpretations. The goal is to continually advance via developing reasonable theories of natural phenomena.
See http://antspub.com You can freely download my pdf essay “The Three “S’s of Science & the Physics of Humpty Dumpty.”
There is a serious dearth of simple but reliable information regarding universal acceleration for lay readers, probably because it is simply a very complex subject that only some of the subject area experts understand well. I recognize that I may have understood something, but I don't think anyone here can clearly explain. I previously referenced on of the two original (1998) research papers.
Reply | Report Abuse | Link to thisIf you can possibly access the Cornell archive site, there is a recent, reasonably simple summary paper: "The Accelerating Universe", Dragan Huterer, 2010,
http://www.arxiv.org/pdf/1010.1162
Its described as an "Invited review chapter for book aimed at general scientists (ed. D. Goodstein)"
The section, "The discovery of dark energy" states:
"The results of the two teams agreed, and indicated that more distant SN are dimmer than would be expected..."
This understanding of the SNe Ia observational results that I've based my reasoning on. Since it apparently cannot be understood, any further attempts to explain would be futile.
Surely you can find the most often uncited reference - the Wikipedia entry "Dark energy"; section "Implications for the fate of the universe"
http://www.en.wikipedia.org/wiki/Dark_energy#Implications_for_the_fate_of_the_universe
It simply states "Cosmologists estimate that the acceleration began roughly 5 billion years ago."
Several NASA documents refer to the start of acceleration occurring from 'several' to 9 billion years ago. I won't list them all here, but none seem to me to be definitive sources.
I strongly recommend Saul Perlmutter's Physics Today article, “Supernovae, Dark Energy, and the Accelerating Universe”;
http://www.courses.ncssm.edu/kolena/lambda/PhysicsTodayArticle.pdf
It is a complicated subject, but explained about as simply as possible in this article.
I have no idea where you've gotten your information.
Somebody must have written a book...
"I have no idea where you've gotten your information. Somebody must have written a book..." quoted from jtdwyer's reply #44.
Reply | Report Abuse | Link to thisPlease read Robert P. Kirshner's book: "The Extravagant Universe: Exploding Stars, Dark Energy and the Accelerating Universe." Kirshner & Perlmutter were both on the front lines of the discovery of what is, and has been dubbed "dark energy" or that the universe's expansion is accelerating.
I'm totally puzzled about what your main point is. What are you suggesting? 1. There isn't any dark energy 2. there is but it is misunderstood 3. The universe is and was just fine prior to these type 1a supernovae studies. 4. Anything I think is true and studies that I don't approve of are misleading 5. No ... to all of the above: what I think is something else. Okay if its number 5, please be clear and open. Fuzzy writing doesn't make sense!
Well, you suggested that I should download and read Saul Perumutter's article among others. I have to admit I've only had time to skim read his article but he is totally on board with Kirshner. Perlmutter's last statement is revealing:
"With advancing technology, we have begun to make philosophically significant measurements. These measurements have already brought surprises. Not only is the universe accelerating, but it apparently consists primarily of mysterious substances. We’ve already had to revise our simplest cosmological models. Dark energy has now been added to the already perplexing question of dark matter. One is tempted to speculate that these ingredients are add-ons, like the Ptolemaic epicycles, to preserve an incomplete theory. With the next decade’s new experiments, exploiting not only distant supernovae, but also the cosmic microwave background, gravitational lensing of galaxies, and other cosmological observations, we have the prospect of taking the next step toward that “Aha!” moment when a new theory makes sense of the current puzzles."
A closer reading of his earlier statements show that Perlmutter, like Kirshner, doesn't doubt the implication of his studies. Dark energy is real and the universe's rate of expansion is accelerating. What is uncertain is the micro-realm mechanism or what is causing it? However we are still in the same place with gravity. We know what it does, but still do not understand its micro-realm dynamics.
Spoken like a true believer who read a book.
Reply | Report Abuse | Link to thisRe:Spoken like a true believer who read a book. quoted by jtdwyer #46.
Reply | Report Abuse | Link to thisYou still haven't clearly stated what you think about dark energy and the expansion of the universe. If you can, set us (i.e., including much of the physics/cosmology) community) straight. These scientists/researchers aren't fools but they (as am I) are open to correction.
I'll repeat myself in an attempt to clarify. I will not simplify to the extent that critical information is omitted.
Reply | Report Abuse | Link to this"The distances of the high-redshift SNe Ia are, on average, 10% to 15% farther than expected..." - from "Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant", Adam G.Riess et al, 1998;
http://arxiv.org/abs/astro-ph/9805201v1
"The results of the two teams agreed, and indicated that more distant SN are dimmer than would be expected..." - from "The Accelerating Universe", Dragan Huterer, 2010,
http://www.arxiv.org/pdf/1010.1162
It is the light from more _distant_ supernova and their host galaxies that indicated to the High-z Supernova Search Team and the Supernova Cosmology Project that the expansion of the universe is currently accelerating.
They used standard cosmological models to determine object distance from redshift based on cosmological assumptions and equations representing their effect of redshifting light's spectra as well as determining distance more directly from type Ia supernovae luminosity.
While the two methods of determining distance produced agreeable results for nearer galaxies, more distant galaxies produced conflicting results.
The researchers were able to produce agreeable results for more distant objects by modifying their cosmological assumptions to include a positive cosmological constant parameter ('vacuum energy density') and a negative deceleration parameter (intended to indicate acceleration). Based on these results, it was concluded that the expansion of the universe is currently accelerating.
I contend that light emitted long ago from distant objects reflects the conditions of spacetime expansion that it encountered from the moment of its emission to the moment of its detection. Since more ancient light emissions from more distant objects indicates greater expansion than does more recently emitted light from nearer objects, it should only have been the more _ancient_ conditions of spacetime expansion that imparted whatever conditions indicated to researchers that expansion was at some time increased.
Greater expansion in the more ancient universe should only be considered as evidence that expansion is currently _diminishing_, as originally expected by the physics community.
Frankly, I'm not interested in any further discussion at this time. Please feel free to discuss among yourself.
In the determination that the expansion of the universe is currently accelerating described above, I think it is the astronomical perspective of observation that most influences the outcome of researchers' analyses. I don't know if anyone can understand, but the following to me best describes the principal source of error contributing to the erroneous conclusion that the actually currently decelerating expansion of universal spacetime is instead accelerating.
Reply | Report Abuse | Link to this"High-redshift SNe Ia are observed to be dimmer than expected in an empty Universe (i.e., mass density = 0) with no cosmological constant."
The above statement infers that the researchers consider that it is the more distant galaxies that are, temporally, physically receding away from the observer as the universe develops, in accordance with their methods used to predict the distances to observed objects.
This view explains the researchers' implicit presumption that a current acceleration in the expansion of the universe would primarily affect the distances to more distant galaxies.
Conversely, I assert that it is more critically the age of the detected light's emission that is actually being determined: that in turn determines what time span in the temporal development of the universe applies to the observed light. The temporally varying conditions of universal spacetime expansion that apply to a given sample of detected light depend on when it was traversing expanding spacetime.
In this view, all detected light emissions have been affected by the conditions of spacetime expansion contemporaneous to the moment of its detection. A current acceleration of universal expansion would increase the distance to _all_ observed galaxies, but _mostly_ the more recent light emissions of _nearer_ galaxies, not more distant galaxies.
In an actual currently accelerating universe, it is the more recently emitted light from nearer galaxies would have been affected more by the more recently increased spacetime expansion than by earlier, lower rates of spacetime expansion.
Since cosmological model parameters had been previously calibrated to the available observations of nearer galaxies, it is the light from more distant galaxies that produced the unexpected results. It is the previously unevaluated expansion of the early universe, represented by the more ancient light emission of more distant supernovae, that produced unexpected, inconsistent modeling results.
Thank you JT, I agree wthe way you indicate our present position in science, when everybody thought that the earth was flat, our view was not wide enough to comprehend the "real" form of our earth, we are still in the process of learning, and for the dark matter I thought that we did not yet have any "PROOF", only using the explanation of the black matter theory could explain some problems that we encounter in our quest, with our high tech eyes (now high tech, tomorrow old fashioned) we learn each day and night, we assume that 380.000 years after point ZERO (I dont like the word BIG BANG) first light was emitted, at that time all the material , also ours, was on that sphere, going frther back we meet the Wall of Planck (10 force -43sec), before this moment no more linear time so no BIG BANG, the socalled ZERO point does not exist in the way we can perceive, also this tiny sphere is everywhere in our world, in my opinion before the wall of Planck the so called INFLATION took not place, because nothing can take place in this precausal prelinear universes, the volume of our universe "emerged", in this pre linear dimension all possible multiverses and paralel universes are united, one of the effects of this "fifth" dimension is gravitation, the other black matter , our universe being an hologram in/around this fifth dimension. 5 billion yeras ago as we can perceive it now our universe began to expand "more", perhaps we reached with our byrionic matter a critical phase with the fields of gravitation and other forces that we cannot still explain, but our five senses will become more and more sensitive so......
Reply | Report Abuse | Link to thisThe Everlasting Theory, which starts from only seven parameters, shows as follows.
Reply | Report Abuse | Link to thisThe dark energy appeared due to the collapse of the object before the ‘soft’ big bang after the period of inflation. The dark energy is the thickened Einstein spacetime composed of the non-rotating binary systems of neutrinos. To detect the non-rotating binary systems of neutrinos we should measure the mass with accuracy about 10^-67 kg.
The dark matter consists of the iron-nickel lumps entangled via the entangled binary systems of neutrinos the Einstein spacetime consists of. The dark matter and its entanglement appeared just at the beginning of the ‘soft’ big bang so its temperature is the same as the CMB radiation. This temperature causes that detection of the dark matter is very difficult. The entangled binary systems exchange the faster-than-light binary systems of the closed strings the neutrinos consist of. The entangled photons decayed to photons containing smaller number of entangled photons so with time matter was more transparent for the smaller entangled photons. The Everlasting Theory shows that number of photons increased significantly 13.2 and 5.7 billion years ago. The ‘soft’ big bang started about 21 billion years ago and the dark era of the Universe lasted 7.5 billion years. Future observations will show that there were big cosmic structures in the DARK ERA of the Universe. Today, the front of the baryonic matter is moving with radial speed equal to 0.6415 of the speed of light. It is obvious that we cannot observe this motion (today) due to the finite speed of light emitted by the cosmic objects. The second flare up of the Universe leads to the illusion of acceleration of expansion of the Universe.
We see that origin of the dark energy and dark matter is associated with structure and interactions of the binary systems of neutrinos. Their interactions lead to the fractal fields too.
The calculations lead to: 74% of the dark energy, 22% of the dark matter and 4% of the visible matter.
In the massive spiral galaxies, the mass of the black hole in centre should be smaller when total mass of stars and dark matter is greater. It follows from fact that growth of size of a massive spiral galaxy is due to evaporation of the black hole in its centre. The evaporation was due to the inflows of the dark energy. The protogalaxies composed of the neutron black holes (each black hole in our Universe has granular structure) arose already before the ‘soft’ big bang.