The Dark Side

No, I am not going to talk about the “Dark Side” of the mythical “Force” out of Star Wars Saga… what set my mind thinking on the dark side of things is an interesting piece of article which caught my attention.

In 1998, astronomers made an astounding discovery that shook the foundations of modern physics: contrary to expectations, the expansion of our Universe is revving up. We live in a runaway Universe, where the most distant observable galaxies are racing away from us at ever increasing speeds.

But what is causing this cosmic acceleration? No one knows for certain, but whatever dark energy actually is, detailed measurements reveal that it comprises a whopping 74% of our Universe's total mass-energy budget!

As the Universe's dominant form of energy, dark energy plays a crucial role in determining how the cosmos evolves, and it will determine whether our Universe expands forever or collapses upon itself.

According to NASA’s website article on Dark Energy - Dark energy has the cosmologists scratching their heads. Observations taken by NASA's Hubble Space Telescope and future space telescopes will be needed in order to determine the properties of dark energy.

Probing dark energy, the energy in empty space causing the expanding universe to accelerate, calls for accurately measuring how that expansion rate is increasing with time. Dark energy is thought to drive space apart.

In physical cosmology and astronomy, dark energy is a hypothetical form of energy that permeates all of space and tends to increase the rate of expansion of the universe. Dark energy is the most popular way to explain recent observations that the universe appears to be expanding at an accelerating rate. In the standard model of cosmology, dark energy currently accounts for 74% of the total mass-energy of the universe.

NASA has developed the Beyond Einstein Program, a series of missions designed to probe fundamental questions about dark energy, black holes, and the very early Universe.

One of the missions is the Joint Dark Energy Mission (JDEM), which will study dark energy.

Two other Beyond Einstein missions, International X-ray Observatory (IXO, formerly Con-X) and the Laser Interferometer Space Antenna (LISA), will provide crucial independent measurements of dark energy.

The exact nature of this dark energy is a matter of speculation. It is known to be very homogeneous, not very dense and is not known to interact through any of the fundamental forces other than gravity. Since it is not very dense — roughly 10−29 grams per cubic centimeter — it is hard to imagine experiments to detect it in the laboratory. Dark energy can only have such a profound impact on the universe, making up 74% of all energy, because it uniformly fills otherwise empty space. The two leading models are quintessence and the cosmological constant. Both models include the common characteristic that dark energy must have negative pressure.

This accelerating expansion effect is sometimes labeled "gravitational repulsion", which is a colorful but possibly confusing expression. In fact a negative pressure does not influence the gravitational interaction between masses - which remains attractive - but rather alters the overall evolution of the universe at the cosmological scale, typically resulting in the accelerating expansion of the universe despite the attraction among the masses present in the universe.

The simplest explanation for dark energy is that it is simply the "cost of having space": that is, a volume of space has some intrinsic, fundamental energy. This is the cosmological constant.

Since energy and mass are related by E = mc2, Einstein's theory of general relativity predicts that it will have a gravitational effect. It is sometimes called a vacuum energy because it is the energy density of empty vacuum. In fact, most theories of particle physics predict vacuum fluctuations that would give the vacuum this sort of energy.

Some theorists think that dark energy and cosmic acceleration are a failure of general relativity on very large scales, larger than super-clusters. It is a tremendous extrapolation to think that our law of gravity, which works so well in the solar system, should work without correction on the scale of the universe. Most attempts at modifying general relativity, however, have turned out to be either equivalent to theories of quintessence, or inconsistent with observations. It is of interest to note that if the equation for gravity were to approach r instead of r2 at large, intergalactic distances, then the acceleration of the expansion of the universe becomes a mathematical artifact, negating the need for the existence of Dark Energy.

Cosmologists estimate that the acceleration began roughly 5 billion years ago. Before that, it is thought that the expansion was decelerating, due to the attractive influence of dark matter and baryons. The density of dark matter in an expanding universe decreases more quickly than dark energy, and eventually the dark energy dominates. Specifically, when the volume of the universe doubles, the density of dark matter is halved but the density of dark energy is nearly unchanged (it is exactly constant in the case of a cosmological constant).

If the acceleration continues indefinitely, the ultimate result will be that galaxies outside the local super-cluster will move beyond the cosmic horizon: they will no longer be visible, because their line-of-sight velocity becomes greater than the speed of light. This is not a violation of special relativity, and the effect cannot be used to send a signal between them. (Actually there is no way to even define "relative speed" in a curved space-time. Relative speed and velocity can only be meaningfully defined in flat space-time or in sufficiently small (infinitesimal) regions of curved space-time). Rather, it prevents any communication between them as the objects pass out of contact.

The Earth, the Milky Way and the Virgo super cluster, however, would remain virtually undisturbed while the rest of the universe recedes. In this scenario, the local super cluster would ultimately suffer heat death, just as was thought for the flat, matter-dominated universe, before measurements of cosmic acceleration.

There are some very speculative ideas about the future of the universe.

One suggests that phantom energy causes divergent expansion, which would imply that the effective force of dark energy continues growing until it dominates all other forces in the universe. Under this scenario, dark energy would ultimately tear apart all gravitationally bound structures, including galaxies and solar systems, and eventually overcome the electrical and nuclear forces to tear apart atoms themselves, ending the universe in a "Big Rip".

On the other hand, dark energy might dissipate with time, or even become attractive. Such uncertainties leave open the possibility that gravity might yet rule the day and lead to a universe that contracts in on itself in a "Big Crunch".

Some scenarios, such as the cyclic model suggest this could be the case. While these ideas are not supported by observations, they are not ruled out. Measurements of acceleration are crucial to determining the ultimate fate of the universe in big bang theory.

However, we need not get overly worried. The timescales being discussed towards the end of the universe range between 30 billion to 50 billion earth years (at least as we know them in present era).

FTL – Finally a possibility in mainstream science

Every now and then, a piece of news begs you to stop, rise above the mundane world of everyday life and reach for the stars and this month… it literally made it possible to reach for the stars – well almost, at least in theory!

Finally two physicists at Baylor University, US, have stumbled upon an idea that may turn traveling at the speed of light from science fiction to real science, just like the warp speed at which spacecraft travel in the fictional TV and film series ‘Star Trek’

Dr. Gerald Cleaver, associate professor of physics at Baylor, and Dr. Richard Obousy, a Baylor post-doctoral student, theorize that by manipulating the space-time dimensions around the spaceship with a massive amount of energy, it would create a “bubble” that could push the ship faster than the speed of light.

To create this bubble, the Baylor physicists believe manipulating the 11-dimension would create dark energy. Cleaver said that positive dark energy is responsible for speeding up the universe as time moves on, just like it did after the Big Bang, when the universe expanded faster than the speed of light.

“Think of it like a surfer riding a wave,” said Cleaver, who co-authored a research paper with Obousy about the new method. “The ship would be pushed by the bubble and the bubble would be traveling faster than the speed of light,” he added.

The method is based on the Alcubierre drive, which proposes expanding the fabric of space behind a ship into a bubble and shrinking space-time in front of the ship.

According to Wikipedia - Alcubierre drive - also known as the Alcubierre drive or Warp Drive, is a speculative mathematical model of a space-time exhibiting features reminiscent of the fictional "warp drive" from Star Trek, which can travel "Faster-than-light".

In 1994, the Mexican physicist Miguel Alcubierre proposed a method of stretching space in a wave which would in theory cause the fabric of space ahead of a spacecraft to contract and the space behind it to expand. The ship would ride this wave inside a region known as a warp bubble of flat space. Since the ship is not moving within this bubble, but carried along as the region itself moves, conventional relativistic effects such as time dilation do not apply in the way they would in the case of a ship moving at high velocity through flat space-time. Also, this method of travel does not actually involve moving faster than light in a local sense, since a light beam within the bubble would still always move faster than the ship; it is only "faster than light" in the sense that, thanks to the contraction of the space in front of it, the ship could reach its destination faster than a light beam restricted to travelling outside the warp bubble. Thus, the Alcubierre drive does not contradict the conventional claim that relativity forbids a slower-than-light object to accelerate to faster-than-light speeds. However, there are no known methods to create such a warp bubble in a region that does not already contain one, or to leave the bubble once inside it, so the Alcubierre drive remains a theoretical concept at this time.

The ship would not actually move, rather the ship would sit in between the expanding and shrinking space-time dimensions. Since space would move around the ship, the theory does not violate Einstein’s Theory of Relativity, which states that it would take an infinite amount of energy to accelerate an object faster than the speed of light.

String theory suggests the universe is made up of multiple dimensions. Height, width and length are three dimensions, and time is the fourth dimension. Scientists believe that there are a total of 10 dimensions, with six other dimensions that we cannot yet identify. A new theory, called M-theory, takes string theory one step farther and states that the “strings” actually vibrate in an 11-dimensional space. It is this 11th dimension that the Baylor researchers believe could help propel a ship faster than the speed of light.

Gee – the only thing left to invent now is “inertial dampening” and “shields” J I wonder what Zefram Cochrane would have thought of this…

So…the theory is there. Implementation waits the perception of our current technologies in higher dimension. Accelerating masses generate gravitational radiation in higher dimension. That side of the universe in completely dark for us as we cannot perceive anything beyond the three spatial dimensions and one forward moving time dimension.

The theory of relativity predicts that masses being accelerated should emit ``gravitational radiation’’ in the same way that charged particles (like electrons) emit electromagnetic radiation when they are accelerated.

Simply put use of gravitational wave in higher dimensions easily produce thousand time faster speed than light. The waves and radiations that we can perceive are designed to explicitly manifest themselves in 3-d spatial environments. Gravity radiation is what runs the chilled universe, the Hyperspaces and zillion universes held by the chilled platform universe.

I think this piece of theoretical work has important connotations for humanity and its future and I for one would closely follow any developments – theoretical or experimental in this field…

What is time?

"The most exciting phrase to hear in science, the one that heralds new discoveries, is not 'Eureka!' (I found it!) But 'That's funny ..." Isaac Asimov

As I sit on a Sunday morning, pondering about fast the weekend went by and how less the time seems to be when you are having fun… a thought struck me – what is time? Often the immediate concept that comes to mind is a clock, watch or a calendar, but what really is time?

According to John Sankey, to physicists, time is defined by quantum mechanics. A photon with energy h (Planck's constant) behaves as though it were oscillating once per second. Modern atomic clocks are based on this. Time direction is something else. It is based on information, which sits uneasily in the world of physics. But, any quantum system must have an arrow of time.

You often hear: “I have no time.”, “Time is money.”, “I need to be on time” and so on.

I have read through some scientific literature and what the scientific community considers as time if even more confusing than our everyday common sense notions about it, for example the Einstein theory of relativity makes the subject for ordinary people just even more confused.

What if time were to stop?

As L. Ron Hubbard (1951) had put it - The illusion called time is composed of altering of the particles position in space” and “Alteration is the basic manifestation of time. Well, he was much more of fantasy novel writer than actual scientist (some may dispute the fact).

Everything moves, all the time. Time is measured from instruments which from beginning come from natural movements such as the sun and the planet as well as the moon. When we think of time we tend to think of the ways in which we measure the passing of time, such as a clock or watch, or perhaps a measured interval of time such as an hour or minute, but not of time itself. So what is time? Exactly what is it that we are measuring?

We can begin to answer the question with the basic description that we are measuring the interval between events, using units that we have chosen for the purpose. We may say, for example, that the next train will be due in 5 minutes. While this information may be very useful for telling us how late the train is when it eventually arrives, it does nothing to describe just what it is that we are measuring. We want to know exactly what the 'interval' is.

Time can seem as solid as a rock. In fact, it's a lot more squishy. Our calendars are imperfect. We need a leap day to keep them in line with the seasons, and even so, time will eventually get away from us. "If you feel there aren't enough hours in a day, just wait," says Max Tegmark, a cosmologist at the Massachusetts Institute of Technology. "In a few hundred million years, tidal friction will have slowed Earth's rotation to make the day 25 hours long."

If that doesn't make your head spin, consider that in physics, motion alters time; in psychology, different stimuli alter our perception of time; and in philosophy, there's disagreement on whether time is even real. "In terms of our inner lives, no time exists except for what is happening in the present moment," says Joan Halifax Roshi, a Zen Buddhist teacher.

Whew!

And I thought time was such a simple matter to ponder about…

In physics and other sciences, time is considered one of the few fundamental quantities. Time is used to define other quantities – such as velocity – and defining time in terms of such quantities would result in circularity of definition. An operational definition of time, wherein one says that observing a certain number of repetitions of one or another standard cyclical event (such as the passage of a free-swinging pendulum) constitutes one standard unit such as the second, is highly useful in the conduct of both advanced experiments and everyday affairs of life. The operational definition leaves aside the question whether there is something called time, apart from the counting activity just mentioned, that flows and that can be measured. Investigations of a single continuum called space-time brings the nature of time into association with related questions into the nature of space, questions that have their roots in the works of early students of natural philosophy.

Among prominent philosophers, there are two distinct viewpoints on time.

One view is that time is part of the fundamental structure of the universe, a dimension in which events occur in sequence. Time travel, in this view, becomes a possibility as other "times" persist like frames of a film strip, spread out across the time line. Sir Isaac Newton subscribed to this realist view, and hence it is sometimes referred to as Newtonian time.

The opposing view is that time does not refer to any kind of "container" that events and objects "move through", nor to any entity that "flows", but that it is instead part of a fundamental intellectual structure (together with space and number) within which humans sequence and compare events. This second view, in the tradition of Gottfried Leibniz and Immanuel Kant, holds that time is neither an event nor a thing, and thus is not itself measurable nor can it be traveled.

According to Lee Smolin, The debate between absolute and relational time echoes down the history of physics and philosophy, and confronts us now, at the end of the twentieth century, as we try to understand what notion of space and time is to replace Newton's. If there is no absolute time, then Newton's laws of motion don't make sense. What must replace them has to be a different kind of law that can make sense if one measures time by any clock. That is, what is required is a democratic rather than an autocratic law, in which any clock's time, imperfect as it may be, is as good as any other's. Leibniz was never able to invent such a law. But Einstein did, and it is indeed one of the great achievements of his theory of general relativity that a way was found to express the laws of motion so that they make sense whichever clock one uses to embody them with meaning. Paradoxically, this is done by eliminating any reference to time from the basic equations of the theory. The result is that time cannot be spoken about generally or abstractly; we can only describe how the universe changes in time if we first tell the theory exactly which real physical processes are to be used as clocks to measure the passage of time.

The problem is that general relativity is only half of the revolution of twentieth-century physics, for there is also the quantum theory. And quantum theory, which was originally developed to explain the properties of atoms and molecules, took over completely Newton's notion of an absolute ideal time.

So, in theoretical physics, we have at present not one theory of nature but two theories: relativity and quantum mechanics, and they are based on two different notions of time.

“In the theory of relativity, the concept of time begins with the Big Bang the same way as parallels of latitude begin at the North Pole. You cannot go further north than the North Pole,” says Kari Enqvist, Professor of Cosmology.

One of the most peculiar qualities of time is the fact that it is measured by motion and it also becomes evident through motion.

According to the general theory of relativity, the development of space may result in the collapse of the universe. All matter would shrink into a tiny dot again, which would end the concept of time as we know it.

No general agreements here, although the search for the grand unified theory is on the achievement does not appear to be any closer still.

There is of course, like anything else under the purview of human thought, an alternate, more human approach towards time…

Spiritual guide and alternative medicine expert Deepak Chopra, who warned of the dangers of a hectic lifestyle. "People who feel that they are 'running out of time' have speeded up their biological clocks," says Chopra. "They have faster heart rates and jittery platelets with high levels of adrenaline. When they drop dead from a premature heart attack, they have literally 'run out of time.'"

Perhaps the most surprising thing we heard about time came from a scientist and entrepreneur who studies aging. "Time has little impact on biology," says Michael West, a gerontologist who teaches at the University of California, Berkeley, and founded the biotech company Geron. That sounds reassuring at first--but it's only because we're pre-programmed to fall apart anyway. "From a gerontologist's standpoint, biological time is not wear-and-tear, it's a genetic program," says West. "It's sort of like a time bomb. The cells are programmed to last just long enough for us to rear children, and no longer."

If now is both now and forever, as C.S. Lewis suggested, then the religious view may not be so different than the scientific view. Physics tells us that all moments exist equally, at once--it's only our consciousness that distinguishes the present from the past or future.

According to The Internet Encyclopedia of Philosophy, “Time has been studied by philosophers and scientists for 2,500 years, and thanks to this attention it is much better understood today. Nevertheless, many issues remain to be resolved. Here is a short list of the most important ones—what time actually is; whether time exists when nothing is changing; what kinds of time travel are possible; why time has an arrow; whether the future and past are real; how to analyze the metaphor of time's flow; whether the future will be infinite; whether there was time before the Big Bang; whether tensed or tenseless concepts are semantically basic; what is the proper formalism or logic for capturing the special role that time plays in reasoning; and what are the neural mechanisms that account for our experience of time”.

There are 3 competing theories:

--> Presentists argue that necessarily only present objects and present experiences are real, and we conscious beings recognize this in the special "vividness" of our present experience

--> According to the growing-universe or growing-block theory, the past and present are both real, but the future is not because the future is indeterminate or merely potential

--> The third and more popular theory is that there are no significant ontological differences among present, past and future because the differences are merely subjective. This view is called "the block universe theory" or "eternalism."

Although there are theories of how to solve a specific problem about time, it is always better to knit together solutions to several problems. Ideally, the goal is to produce a theory of time that will solve in a systematic way the constellation of problems involving time. What are those problems?

--> One is to clarify the relationship between time and the mind. Does time exist for beings that have no minds? It is easy to confuse time itself with the perception of time.

--> Another problem is to decide which of our intuitions about time should be retained. Some of these intuitions may reflect deep insights into the nature of time, and others may be faulty ideas inherited from our predecessors. It is not obvious which is which. For one example, if we have the intuition that time flows, but our science implies otherwise, then which view should get priority? Philosophers of time must solve the problem of how to treat our intuitions

--> A third problem for a philosophical theory of time is to clarify what physical science presupposes and implies about time. Most all philosophers of time claim that philosophical theories should be consistent with physical science, or, if not, then they must accept the heavy burden of proof to justify the inconsistency

A philosophical theory of time should describe the relationship between instants and events. Does the instant that we label as "11:01 A.M." for a certain date exist independently of the events that occur then? In other words, can time exist if no event is happening? This question or problem raises the thorny metaphysical issue of absolute vs. relational theories of time.

The article is profound in its depth and I strongly recommend reading, though not on a Sunday afternoon, when one is more attuned towards a lazy stroll through time rather than an activity which challenges the one’s intellect and imagination both.

Although we understand that Time is a component of a measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify the motions of objects, Time has been a major subject of religion, philosophy, and science, but defining time in a non-controversial manner applicable to all fields of study has consistently eluded the greatest scholars. Also, throughout my readings, the concept of time, which we all take for granted, is still far from being agreed upon by most of the branches of human thought from Physics to religion. It is profoundly disturbing and humbling to know that we know how to split an atom, reach the moon and gaze at the depth of cosmos, we are still not quite sure what time is… although we can experience its effects on everything we see around us…