ADVERTISEMENT
  About the SA Blog Network













Basic Space

Basic Space


Space and astrophysics research made simple
Basic Space Home

How most of the universe was lost

The views expressed are those of the author and are not necessarily those of Scientific American.


Email   PrintPrint



Brian Schmidt at Lindau. Credit: Markus Pössel

When Brian Schmidt got his PhD in astrophysics in 1993, he was one of less than a handful of people that year that graduated with a thesis on supernovae. Five years later, still working on exploding stars, he would be part of one of two teams that independently discovered that the universe was not only expanding, but that its expansion was accelerating.

That the expansion of the universe is accelerating means it is being pushed apart by some kind of energy embedded in the fabric of space itself. This energy makes up over 70% of the universe. We call it dark energy, mainly because we are in the dark about what it actually is.

The 2011 Nobel Prize in Physics was awarded to Brian Schmidt, along with Adam Reiss, who worked with Schmidt as part of the High-z Supernova Search Team, and Saul Perlmutter, who headed the rival Supernova Cosmology Project, for their discovery of the accelerating expansion of the universe. The announcement of the prize called dark energy “perhaps the greatest enigma in physics today”.

When Schmidt attended the 62nd Lindau Nobel Laureates Meeting in Germany earlier this month, I met him and found out more about the discovery.

Big questions

“I liked the fact that supernovae changed,” Schmidt says of his PhD topic. “That appealed to me.”

For his PhD, Schmidt developed a way to measure the distances to type II supernovae, explosions of massive stars that have come to the end of the main part of their life. Type II supernovae differ from other types in that they have hydrogen in the spectrum of light we detect coming from them. He used these distance measurements to calculate a number called the Hubble constant that you can use to work out the age of the universe. The idea was that you can use this to look back and work out how fast the expansion of the universe is slowing down – because, at the time, that’s what people thought was happening. “It tells you the ultimate fate of the universe. Gosh, that was a big question,” says Schmidt. “I loved it.”

By 1994, after Schmidt’s PhD, technology had advanced so much that supernova distances were now measurable accurately. “[The Supernova Cosmology Project] had been looking for supernovae for six years and suddenly were able to find them,” says Schmidt. The Supernova Cosmology Project had started in 1988, with Saul Perlmutter at its head. The project was looking for type Ia supernovae, which result from the explosion of a white dwarf – a star that is itself a remnant of a star, no bigger than about one a half times the mass of the sun, that has stopped fusing hydrogen and helium. The light from type Ia supernovae always follows the same pattern, meaning astronomers can work out how far away one particular stellar explosion is by its brightness (for example, see this).

“We talked about working with them,” says Schmidt. But both groups had strong views over how the work should be carried out. “We had disagreements and it was very clear that they did not want us involved in their experiments,” he added.

But Schmidt still felt that what he wanted to do was the right thing to do at the time. So he dropped everything else and did it. Along with Nicholas Suntzeff, he formed the High-z Supernova Search Team in 1994 to compete with the Supernova Cosmology Project in tracing the expansion of the universe using type Ia supernovae. Adam Reiss took charge of the High-Z team’s data. At the time Schmidt was supposed to be working on another project, but abandoned it. “There was no sense in working on anything else because this was what I wanted to do,” he says.

“I remember saying that if those guys can find them we can,” says Schmidt. He describes himself at that time as young, arrogant and naïve. “It’s always good to be naïve,” he says. It was a bold move. Luckily, the risk paid off.

First light

Soon the High-z Supernova Search Team got their first data set, from supernova 1995K. By September 1997 they were still gathering data, but nothing looked amiss just yet. “At that point it was consistent with something reasonable,” Schmidt says.

But by the end of 1997 it became clear that the High-z Supernova Search Team’s results were anything but reasonable. The supernovae seemed to be telling them that the expansion of the universe, far from slowing down, was in fact speeding up. “Adam [Reiss] put all that data together and he sent me a figure,” says Schmidt. “It said ‘What do you think of this?’ as the subject line of the email and that was it.”

Schmidt and Reiss spoke on the phone to discuss the paradigm-shifting figure Reiss had emailed. They decided to go through every step of the data analysis again before talking to anyone else about it. “My initial reaction was that we must have made some kind of mistake,” says Schmidt.

They started that painstaking process at the end of November. “I was learning this stuff on the fly at this point because it was very clear that we had to do something new,“ says Schmidt. By the beginning of January they agreed on “every single bit” of the analysis. “I remember the moment when I thought: We’re going to have to tell everyone in the team about this. And then we’re going to have to tell the world about it at some point,” he says.

Some members of the research team were understandably uneasy with the findings. Schmidt recalls telling them: “I find it disturbing too, but I’ve been working on it for the last six weeks and can’t make it go away.” The team was able to come up with some tests that Schmidt and Reiss hadn’t done. So they did those over the next couple of months.

But the accelerating universe was still there.

Closing in

The whole time that Schmidt’s group was working on checking and rechecking their analyses they knew that Saul Perlmutter’s group were working on the same problem as them, trying to measure the expansion of the universe with supernovae. But they had thought that their rivals were getting the opposite answer, one that said the expansion of the universe was slowing down, as everyone expected.

They weren’t. On 8th January 1998, Saul Perlmutter, on behalf of the Supernova Cosmology Project, presented data at the American Astronomical Society meeting in Washington, D.C., that hinted at an accelerating universe. The next day, Charles Petit at the San Francisco Chronicle reported the finding on the front page of the newspaper. This was the first that anyone at Schmidt’s group had heard about the Supernova Cosmology Project’s data.

“That certainly made us focus our attention,” says Schmidt, who didn’t make it to the AAS meeting himself. “We went charging ahead. We showed the world our results on 23rd February. [Perlmutter’s group] were completely surprised by it,” says Schmidt.

When they announced their evidence for the accelerating universe, Schmidt was worried they would be “crucified”. But the fact that there were two teams that independently came to the same result at the same time was a big deal, he says.

Fixing problems

The other thing that helped the result gain acceptance was that it solved an awful lot of problems. “It had been known for the previous seven or eight years that a cosmological constant, if it existed, would explain several of the anomalies in the cosmological model at the time,” says Schmidt. A cosmological constant is the simplest possible description of dark energy, the force causing the acceleration of the universe. It was, bizarrely enough, first suggested by Albert Einstein as a way to make his equations describe a static universe. He quickly dropped his version of the cosmological constant when astronomers in the 1920s discovered that the universe was not static after all, but expanding. But since the discovery of the accelerating universe and dark energy, a cosmological constant term has found favour once again as a way to make the equations describing the universe fit with what astronomers see. Adding a cosmological constant essentially has an anti-gravity effect on the universe, allowing it to push itself apart when it should be slowing down.

Many aspects of cosmology suddenly made sense when a cosmological constant was added to the mix. “The whole inflation scenario was easily explained if there was a cosmological constant,” Schmidt says. “It made large scale structure work. It made the universe flat, it made the universe the right age. It meant that the Hubble constant could be up where we measured it. It meant that [the universe’s matter density] could be where we measured it. All the things worked.”

The High-Z Supernova Search Team had been careful not to announce a discovery, but rather observational evidence. Both they and the Supernova Cosmology Project had three-sigma confidence, meaning that the probability their results were down to chance was 0.27%. Together they had four and a bit sigma – giving an even smaller probability that it was down to chance. But still big enough for some people to worry about. So they worked in the years afterwards to build up the proof.

The reality of the finding really sunk in for Schmidt in 2000, he says. Two separate experiments, MAXIMA and BOOMERANG, that had both measured photons left over from the early universe, known as the cosmic microwave background, had shown that the universe was flat. Their findings fitted in with a universe that had undergone an early period of fast inflation, contained that elusive stuff dark matter – and, most importantly, required a cosmological constant. “I just couldn’t see any way to get rid of it at that point,” Schmidt says.

Missing universe

“The only problem with the standard model of cosmology is that it requires us to invent 95% of the universe”

Fast forward to last month and Schmidt was presenting his lecture at the 2012 Lindau Nobel Laureates meeting. If anyone hadn’t quite woken up for the first lecture on Monday morning, that sentence was sure to do the job. Schmidt was referring to the fact that only about 5% of the energy density of the universe is made up of ordinary matter like atoms. Some 23% is dark matter. The remaining 70%+ is the dark energy driving the universe’s accelerating expansion. “I still don’t like it,” Schmidt says. “But it works, and ultimately, it’s not so ugly that we shouldn’t live with it.”

We may have to live with dark energy, but finding out what exactly it is will prove an incredible challenge. The cosmological constant is just one idea, and even that is more of a starting point than a final answer. It needs digging into in a lot more detail to get a better description of the state and future of the universe. But that will not be easy. “The reality is it’s going to be very difficult to get our hands on that dark energy sector. Because we’re not going to create it in the lab, that’s the problem,” says Schmidt.

He does have some ideas, however. “If I could do my big experiment to measure the equation of state parameters [the numbers that cosmologists plug into equations that describe the universe] I’d use baryon acoustic oscillations.”

Baryon acoustic oscillations are fluctuations in the density of matter caused by acoustic waves in the early universe. They left an imprint in the clustering of galaxies and matter today. We know how big they should have been in the early universe, so by looking at the separation of galaxies today astronomers can work out how far away those galaxies are – and map the expansion of the universe.

“But I’m going to let someone else do that,” says Schmidt.

From 1st to 6th July I was at the Lindau Nobel Laureates Meeting in Germany as part of the Lindau blog team. You can read my posts from there here or on the Lindau blog.

*

Updated 5th August 2012, to reflect Nicholas Suntzeff’s role in the formation of the High-Z Supernovae Search Team (see his comment).

Kelly Oakes About the Author: Kelly Oakes has a master's in science communication and a physics degree, both from Imperial College London. Now she spends her days writing about science. Follow on Twitter @kahoakes.

The views expressed are those of the author and are not necessarily those of Scientific American.





Rights & Permissions

Comments 24 Comments

Add Comment
  1. 1. jtdwyer 1:42 am 07/31/2012

    As I understand, it was determined that the expansion of the universe had begun accelerating about 5 billion years ago based on discrepancies between distance estimates based on SN Ia luminosity and then standard cosmological models based on the redshift of their host galaxies. The researchers were able to mathematically resolve the discrepancies (which could only be observed out to a distance of about 5 billion light years and, did not occur for model estimates nearer than about 3 billion years away) by supplying cosmological constant and negative deceleration parameters to cosmological models. As a result, it was concluded that, rather than decelerating as was expected, universal expansion was now accelerating (although this could not be confirmed for for the periods of 3 billion years ago to the present). As I recall, once it was found that the discrepancy could be resolved by the parameter adjustments, no further analysis of possible alternative interpretations was pursued.

    Likewise, the presence of and requirements for dark matter have all been inferred by discrepancies between observed and modeled or more simply presumed (in the case of non-Keplerian galaxy rotation curves) predictions of gravitational effects for large to very large scale aggregations of billions of massive objects.

    Could be some problem with the models (especially for dark matter inferred because spiral galaxies do not happen to comply with the laws of planetary motion).`

    Link to this
  2. 2. vinodkumarsehgal 3:28 am 07/31/2012

    Expansion of universe is normally interpreted as the expansion of space. Nature of space and its physicality is not well understood. No labels can be assigned to space to establish its direct expansion. Expansion of space is established indirectly by observing the dispersal of remote galaxies and that too by observing red shift of light propagating for billion of light years thru unknown universe. No red shift has been observed for galaxies lying within distance of about 1 billion light years from earth. When intra galactic space expands, space might be providing some push to the galaxies to go apart or material galaxies are geared within space firmly. In either case, it implies matter of galaxies remain bonded ( an attractive force between matter and space) to space so that additional created space also drags the galaxies along with it or pushes galaxies apart. This mechanism of space in some bond with matter is not known

    Despite the fact that our knowledge of space, physicality of space, expansion of space, force acting between matter and space is far from rudimentary, scientists are talking of accelerating expansion of space. And Nobel prizes have been conferred for the discoveries. This is the irony of 21st century Science

    Link to this
  3. 3. Torbjörn Larsson, OM 11:17 am 07/31/2012

    “The only problem with the standard model of cosmology is that it requires us to invent 95% of the universe”

    Well, yes, but old big bang cosmology already required us to invent 100 % of the expansion of the vacuum.

    More specifically, if we don’t have a problem with spacetime expansion, the dark energy growth taking over the universe energy density shouldn’t be a problem.

    @ jtdwyer:

    Of course other cosmologies have been pursued, that is why it is called “standard” cosmology after all. See the WMAP documents on what they tested for, then you have tired light, MOND et cetera who have all had their chances. But right now, and most likely henceforth, the inflationary standard cosmology has replaced the old big bang theory.

    @ vinodkumarsehgal:

    Gravity is what holds the local groups together, and that is part of the current cosmology on those scales.

    The irony of 21st century science is despite all what we know, the detailed analysis behind it, and the obvious observation that “common sense” is not applicable outside of our learned natural environment, non-scientists persist in rejecting science on the naive grounds that they don’t feel comfortable with its results.

    Link to this
  4. 4. jtdwyer 6:05 am 08/1/2012

    Torbjörn Larsson, OM – you stated:
    “Of course other cosmologies have been pursued…”

    I suppose I should have specifically referenced the original research reports that initially concluded that universal expansion is currently accelerating. I think my statement is true in that context. Of course, you’re free to do your own research to disprove my remembrances. But then, you didn’t provide and references, either. BTW, I don’t think the term ‘standard model’ when applied to cosmology means that a consensus of physicists accept what is more properly referred to as the Lambda-CDM model. Unlike the long established and well proven current standard model (of particle physics), I think the term standard is applied to cosmology mostly as wishful thinking…

    Link to this
  5. 5. vinodkumarsehgal 11:24 pm 08/1/2012

    My comments were in the context that when we do not understand fully nature of space, expansion of space and nature of interaction between matter and space, talk of accelerated expansion of space shall be too long.

    If space is vacuum, implying NOTHING, why some force dark or expansion should be required for its expansion?

    Tobjorn Larrson

    I did not ask Torbjorn Larrson OM as to what holds material structures bound in universe – gravitation or some other force.

    If common man can be wrong in their common sense, even learned scientists can be wrong in the interpretation of detailed analysis and observations. Is it not a known fact that scientific theories and ideas are rejected after few decade on evolution of new understanding. After all, those scientific ideas and theories were also the product of detailed analysis and observations

    Link to this
  6. 6. Bill_Crofut 6:22 pm 08/2/2012

    Re: “The only problem with the standard model of cosmology is that it requires us to invent 95% of the universe”

    Some inventions are good (the mouse trap), some are bad (atomic weaponry). In this case, invention would seem to be based on unreality. Why? Consider the “big-bang;” an alleged explosion that produced the unimaginable order observed in the cosmos. This, in spite of the fact that all of human experience has demonstrated explosions (i.e., atomic weaponry) do not generate order, but rather disrupt or destroy the existing order of whatever is the target of the explosion. In fact, that’s the intention.

    Sir Fred Hoyle, in a critique of “big-bang” cosmology noted:

    “…[I]n a single big bang there are no targets at all, because the whole universe takes place in the explosion. There is nothing for the expanding universe to hit against and after sufficient expansion, the whole affair should go dead. However, we actually have a universe of continuing activity instead of one that is uniform and inert…[T]he main efforts of investigators have been in papering over holes in the big-bang theory, to build up an idea that has become ever more complex and cumbersome….I have little hesitation in saying that a sickly pall now hangs over the big-bang theory”
    [1984. The big bang under attack. SCIENCE DIGEST, May, pp. 8, 84]

    Yet, we’re being told, in spite of the lack of a target for the alleged big-bang to hit against, the expansion of the universe is increasing. How does that claim square with the 2nd law of thermodynamics?

    Link to this
  7. 7. basudeba 6:43 pm 08/2/2012

    Dear Sir,

    We don’t understand the excitement relating to the so-called dark energy, which is an oxymoron. It is said to be dark because it does not reveal itself through interaction. It is smoothly distributed in the sense it doesn’t fall into galaxies and clusters, (otherwise it would have been found by studying the dynamics of those objects). It is persistent in the sense the density of dark energy (amount of energy per cubic light-year) remains approximately constant as the Universe expands. It doesn’t dilute away like matter does. Because of the last two properties, it is called energy. But how can energy not interact, yet be called energy? Can it not be explained differently? Say like a back ground structure? That will solve most problems and explain gravity, which in turn can explain the other fundamental forces of Nature. This also will explain inflation, though differently.

    In the paper “Physics Beyond Standard Model”, we have described the above mechanism. The cosmic microwave background measures the total amount of energy (including matter) in the observable universe. Local measures of galaxies and clusters measure the total amount of matter. The latter turns out to be about 27% of the former, leaving 73% or so in the form of some invisible stuff that is not matter. We relate these two theoretically to 1 : π, because the inverse square law is universally verified and only a spherical field must obey the inverse square law because the density of spherical emission must fall off inversely with the distance. The only difference in this case is that there is no fall of density because the galaxies move intact and there is no evidence of their expansion. This implies that they are moving against a fixed back ground like a boat moving in a river. This creates bow-shock effect and we have shown that at a certain point, this not only overcomes the expansion, but also generates a negative pressure. This is repeated to give the impression of inflation.

    We are pained to see the way the scientific community is heading. The misreporting orchestrated in the media about the so-called discovery of Higg’s boson is one of the latest fads. The problem is that scientists are behaving like the proverbial six blind men, who went to “see” an elephant. Each one touched one limb of the elephant and described the entire elephant based on his findings. Each one is correct in his description. But even after listening to all six, you cannot have any idea about what type of a creature they are talking about. But for one who has seen the elephant, all their descriptions make sense. We find the situation similar, but no one is willing to see the elephant, even when it is in sight.

    mbasudeba@gmail.com

    Link to this
  8. 8. vinodkumarsehgal 8:59 pm 08/2/2012

    Could any one amongst the readers or author of this article address the following issue :

    If space is vacuum implying nothing, subtracting all the quantum energies and fields, why some energy — dark or expansion should be required for expansion — accelerated or normal expansion. Energy is required for producing motion in some existence which is material

    Link to this
  9. 9. basudeba 8:28 am 08/3/2012

    This is exactly our point. There is much ado about nothing like the orchestrated media misreporting about the discovery of the Higgs boson. We have written extensively on this and you can see it at basudeba.blogspot.com.

    mbasudeba@gmail.com

    Link to this
  10. 10. patrick 8:34 am 08/3/2012

    Ref. the above Blog,and all the interesting comments that follow,each of which expresses his original thoughts and ask questions,we require a clear cut answer from a highly experienced cosmologist/physicist/Mathematician triple team ,to advise us with physically & practically applicable or optional immaginable answers,whic we can work on.
    Now from the above Blog, the following points requires further answers.
    i) “A cosmological constant is the simplest possible description of dark energy” -but down the lines it will require several Parameters and newly Designed and adaptable Test Instruments,Jigs and-the requisite Fixtures, and a lot of calm and patience -it can be the stubborn work of one lifetime.
    Now to generate the Cosmological Constant,what Types of Matter or Galaxies or Orbital Bodies- are required “Mathematically to be formed on a Cosmological Scale”,the Nature of the Geometrical positions of the Celestial Bodies,and the number of Spherical Bodies involved in a Dynamic Centering-at one Simultaneous Time in Slice of Phase Space, which can be chosen in any arbritrary direction, if all the factors of the required Mathematics,Physics and Cosmology ,are well designed precisely Synchronised.We can select the “Low energy” limits, where the spectrum, below the Planck scale operates,and many of the Laboratories around the world are desperately researching in this Field.
    To find the Cosmological Constant we mist discover the Physical Point spot -where the Space-Time-Dynamic Center of the Spherical Bodies Converge,during the Synchroniztion Time-Lock-,for observing Physically the Cosmological constant, there is no second NATURAL choice.

    Link to this
  11. 11. nsuntzeff 10:18 pm 08/3/2012

    Kelly, actually Brian Schmidt and I formed the HZT in 1994. We brought together our colleagues in Chile, the US, and at ESO in Europe. Among the colleagues was Adam Riess, who was a grad student at Harvard at the time. In 1997 after he finished his PhD, he went to UC Berkeley. I organized the Team such that every six months (which is synchronized with observing time requests) the Team would work together to do the observing and get the data to the university/observatory on the list. The first half of 1997 we worked for the University of Washington. The latter half of 1997 we worked for UC Berkeley. Adam Riess took charge of the data and through his hard work – and the hard work of the HZT – we made the discovery of a negative q0, which has been interpreted as “dark energy” although the simplest interpretation is a kinematical one where the change in expansion is positive at this epoch.

    Previous to the HZT, the astronomers in Chile formed the Calan/Tololo Survey in 1989 which pioneered the use of Type Ia SNe to measure distances, ultimately to 6%. I know this all sounds pedantic, but for some reason the work in Chile both on the C/T and our role in the HZT gets minimized, perhaps because we were located far from the US.

    Link to this
  12. 12. aabuckler 2:04 am 08/4/2012

    Is it possible that the force increasing the rate of expansion of the universe is something external to it?
    I am thinking of the Multiverse idea, where some vast number of parallel universes are supposed to exist side-by-side with our own. Could their accumulated gravitational pulls be felt in our own, effectively pulling ours apart? Also, if space (vacuum) is expanding, does this mean that the individual Planck fluctuations are getting larger, or do they increase in number to fill a larger “volume”? If so, how are they “generated”? – Just a citizen asking questions.

    Link to this
  13. 13. Kelly Oakes in reply to Kelly Oakes 4:46 am 08/4/2012

    nsuntzeff:

    Thanks for your clarification, some of it I was not aware of and other parts I did know but got lost as I tried to keep it simple in the post. I’ll update the post later today to reflect your role in the formation of the HZT.

    Link to this
  14. 14. basudeba 9:07 am 08/4/2012

    Can anyone tell US where is the proof for existence of multiverses? Or science has been reduced to fiction and flight of imagination! We knew that science admits only those facts that can be proved.

    Link to this
  15. 15. patrick 5:27 am 08/6/2012

    Ref.14. Mr basudeba ,in response to your article, you still have awful lot of homework and perspiration to further study issue’s related- to Cylindrical Coordinates transposed to “Spherical coordinates” and vice-versa,under a Phase- Time- Lock Synchronization , this can be achieved in a 5-Dimensional spacetime,in our physical world, stay your cool, and take a deep breath,concentration,focus& patience are th Key word’s!

    Link to this
  16. 16. vinodkumarsehgal 1:48 am 08/9/2012

    To Patrick

    Cosmological constant or dark energy or quintessence have been invoked by Scientists for explaining expansion of space. If space, as pure vacuum devoid of any field or force, is NOTHING and NOTHING means actually nothing in substance, why some energy should be required to be invoked for expansion of NOTHING?

    With the additional creation of space, resulting from expansion of space (If it really happens), from where does additional energy associated with additional space emerges out?

    Why don’t we confront the above issues directly instead of taking refuge in mathematical formulations or indirect observations of red shift? If we do not know answers why don’t we admit that we do not know?

    Link to this
  17. 17. patrick 9:47 am 08/11/2012

    Ref.16. Vinodkumarsehgal, your quote,” 1)Cosmological constant or 2)dark energy or 3)quintessence have been invoked by Scientists for explaining expansion of space……….

    Just invoking the cosmological constant ,will not explain the expansion of space , but rather you should read/study the full Text via -Google for the complete definition ‘s of 1,2,&3++ Homogeneous Fluid’s, Dark matter,Kinematics and its related Phase Space of Celestial Bodies that converges to the form a relaxed fixed point Dynamical driven Vaccum Energy.

    Below is a important reference from “Wikipedia”-Many models of quintessence have a tracker behavior, which according to Paul Steinhardt et al. (1999) partly solves the cosmological constant problem.[2] In these models, the quintessence field has a density which closely tracks (but is less than) the radiation density until matter-radiation equality, which triggers quintessence to start having characteristics similar to dark energy, eventually dominating the universe. This naturally sets the low scale of the dark energy.[3] When comparing the predicted expansion rate of the universe as given by the tracker solutions with cosmological data, a main feature of tracker solutions is that one needs four parameters to properly describe the behavior of their equation of state,[4][5] whereas it has been shown that at most a two-parameter model can optimally be constrained by mid-term future data (horizon 2015-2020).[6]
    Some of the answers to your query, can be summerised from my above Blog Ref 10.

    Link to this
  18. 18. vinodkumarsehgal 3:57 am 08/12/2012

    To Patrick

    Ref your blog 10

    You yourself have conceded that elaboration from some experienced triple team of Cosmologis/Physict/Mathematician shall make things clear.

    In my comments 16, I was not dwelling upon distinction between cosmological constant, dark energy and quintessence. Wikipedia and many other links makes this distinction clear. Whatever variety of expanding agent may be, but fact remains that all these agents are some sort of energy — some physical energy reality

    Blog 10 speaks of dynamic synchronized state of celestial bodies when within phase space-time lock state, cosmological constant is determined.
    My query did not pertain to above issues. My query pertained to a simple and direct issue; If space in its purest form is vacuum implying nothing ( which implies a non physical entity) then why should some energy in some physical form be required for expansion?

    This leads me to think that though space in its purest form may be a non-physical entity but this may be an existential entity even though not existing in some physical form

    Link to this
  19. 19. patrick 5:37 am 08/13/2012

    Vinod Ref.to your question in Blog 18-: Whatever variety of expanding agent may be, but fact remains that all these agents are some sort of energy — some physical energy reality ? and it is not a physical reality in your stated context.

    The Cosmological constant is not a source of energy, but a ” RATIO “stated in Natures physical Space of “TWO Energy sources:”, which meet in Convergence ……… in a explicit QUANTIZED RATIO’S,— “SINGLE QUANTIZED Conicity Scaler Field “,

    1) Positive Mass Energy Density, which orginate’s from a DYNAMICAL / KINETIC IN sources of Orbitals.

    2) Negative Mass Energy Density….which originates from TIME REVERSAL,and is the STATE OF LOWEST POTENTIAL GRAVITATIONAL ENERGY DENSITY………….

    Vinod ,Your Ques ,ref your Blg 16 -:from where does additional energy associated with additional space emerges out?

    Link to this
  20. 20. patrick 5:46 am 08/13/2012

    Vinod ,ef. my Blog 19-Technical failure.

    Vinod Ref.to your question in Blog 18-: Whatever variety of expanding agent may be, but fact remains that all these agents are some sort of energy — some physical energy reality .

    The Cosmological constant is not a source of energy,

    but a ” RATIO “stated in Natures physical Space of “TWO Energy sources:”, which meet in Convergence ……… in a explicit QUANTIZED RATIO’S,— “SINGLE QUANTIZED Conicity Scaler Field “,

    1) Positive Mass Energy Density, which orginate’s from a DYNAMICAL / KINETIC IN sources of Orbitals.

    2) Negative Mass Energy Density….(Dark Matter)which originates from TIME REVERSAL,and is the STATE OF LOWEST POTENTIAL GRAVITATIONAL ENERGY DENSITY………….

    Link to this
  21. 21. vinodkumarsehgal 4:03 am 08/14/2012

    To Patrick

    “Negative Mass Energy Density….(Dark Matter)which originates from TIME REVERSAL,and is the STATE OF LOWEST POTENTIAL GRAVITATIONAL ENERGY DENSITY………….”

    Negative mass energy, whose origin is proposed to be sought from TIME REVERSAL, and which is described to be the state of potential gravitational energy density ….. This lowest energy density may be named by any name vacuum energy or dark energy or any other name, however, this is a physical reality.

    But the fact is that in Physics especially in Relativity Space and Time have not been given any Physical status. However, negative energy, which is described to be a state of lowest potential gravitational energy density, therefore, it carries some physical status.

    In view of above, my queries related to following fundamental issues :

    i) If space (pure vacuum) does not carries any physical reality status implying NOTHING, why some Physical entity — dark energy should be required for its expansion?

    I am not speaking of origin of dark energy or vacuum energy But simply asking a simple and straight query : If space as pure vacuum is Nothing then why some physical reality should be required to be invoked for expansion which by virtue of itself is treated as NOTHING.
    By Pure vacuum, I mean that space which is left after subtracting all sort of quantum fluctuations, quantum energies and quantum fields.

    ii) Negative mass energy density ( vacuum energy/expanding energy/dark energy) may emerge out in the case of TIME REVERSAL. I agree to this extent. But will TIME REVERSAL be fundamental in the origin of negative energy? TIME REVERSAL may provide suitable conditions for the emergence — manifestation of negative expanding energy but not the fundamental cause of the negative energy. Reason? Negative energy has been treated as a physical reality — some tangible status but TIME has not been given any Physical reality status.

    We treat both matter and energy as physical realities but with regard to space ( pure vacuum) and time, we do not assign any fundamental physical status to them. But matter and energy can not operate without space and time. May be our knowledge of space and time is far from rudimentary, therefore, we have assigned nil physical status to them.

    Link to this
  22. 22. patrick 7:24 am 08/15/2012

    REF: 21- Vinod , you misinterpreted the context and meaning of what I explained to you in my Blog…..you confused youself, in Mathematics , physics & cosmology ,you must be patient & understand, if it is not clear ,you can ask ?

    YOU STATED THIS LINE IS INCORRECT !
    – ….. -This lowest energy density may be named by any name vacuum energy or dark energy or any other name, however, this is a physical reality. —

    I WROTE “STATE OF LOWEST POTENTIAL GRAVITATIONAL ENERGY DENSITY………….” IN MY REF: blog – 19.2) Negative Mass Energy Density….which originates from TIME REVERSAL,and is the “STATE OF LOWEST POTENTIAL GRAVITATIONAL ENERGY DENSITY………….” has to be synthesized with the relavant thought analysis & mathematical and Cosmological tools pertaining to a specific applicable Classical Symmmetry.
    READ “Schrödinger equation
    From Wikipedia, the free encyclopedia”
    Quote
    STUDY,analyse this most important ,basic & simple structure of Schrödinger equation
    – The most general form is the time-dependent Schrödinger equation, which gives a description of a system evolving with time[2] :
    Time-dependent Schrödinger equation (general)
    where Ψ is the wave function of the quantum system, i is the imaginary unit, ħ is the reduced Planck constant, and is the Hamiltonian operator, which characterizes the total energy of any given wavefunction and takes different forms depending on the situation.
    “The most general form is the time-dependent Schrödinger equation, which gives a description of a system evolving with time[2]
    Time-dependent Schrödinger equation (general) ……………………….
    where Ψ is the wave function of the quantum system, i is the imaginary unit, ħ is the reduced Planck constant, and is the Hamiltonian operator, which characterizes the total energy of any given wavefunction and takes different forms depending on the situation.”

    Link to this
  23. 23. vinodkumarsehgal 8:38 am 08/15/2012

    To Patrick

    Thanks for your guidance on mathematical aspects. However, you have not addressed my basic query with which I had started the current thread of discussions. I repeat the query once again :

    Space as pure vacuum is considered to have NIL physicality. However, dark energy which scientists have invoked to account for expansion of space is supposed to carry some physicality. This is another matter that physicality of dark energy is yet not known but scientists have attributed 72% of density of universe to dark energy. My straight and direct question was why an entity carrying physicality, and that too to the extent of 72% density of universe, should be required for expansion of space which is considered to HAVE NIL PHYSICALITY.

    To be honest, it is difficult to understand at mental level the expansion of space ( pure vacuum) i.e.an entity which carries no physicality. NIL physicality means NOTHING. Then expansion is of what?

    Secondly, I am not disputing your assertion that negative mass energy density, which represent the lowest gravitational energy density state, and arise from TIME REVERSAL. I also agree that TIME REVERSAL may come into existence from classical dynamic symmetry of celestial bodies in Phase space-Time lock state. But I had raised the query that these conditions may provide suitable conditions for the manifestation of negative mass energy. My query related to the origin of negative mass energy density. pl see my quote in blog 21

    “‘TIME REVERSAL may provide suitable conditions for the emergence — manifestation of negative expanding energy but not the fundamental cause of the negative energy. Reason? Negaive energy has been treated as a physical reality — some tangible status but TIME has not been given any Physical reality status.”

    In your blog 20 at i) and ii), you have indicated the conditions under which POSITIVE MASS ENERGY and NEGATIVE MASS ENERGY DENSITY emerge out but not touched the basic issue viz FROM WHICH SOURCE THESE ENERGIES EMERGE OUT? Are these energies Fundamental in universe or carry their origin to some other reality? Are positive mass energy density and negative mass energy density manifestations from the same source and express differently under different conditions as you have specified at i) and ii) of your blog 20

    Link to this
  24. 24. Kelly Oakes in reply to Kelly Oakes 9:03 am 08/15/2012

    I’m afraid this comment thread has got more than a little off topic now, so I’m going to close it.

    Link to this

More from Scientific American

Scientific American Special Universe

Get the latest Special Collector's edition

Secrets of the Universe: Past, Present, Future

Order Now >

X

Email this Article

X