Category Archives: Physics

What the Difference Between Dark Matter and Dark Energy?

April 30, 2015Categories, Physics, Universe Mysteriesdark energy, dark matter, louis del monte, What the Difference Between Dark Matter and Dark Energy, WIMP particleadmin

Dark matter plus dark energy makes up over 90% of the matter in the universe, and science doesn’t understand the nature or either of them. Normal matter, the stuff we can typically see and touch, makes up only 5-10% of the matter of the universe. That means that science does not understand over 90% of what makes up the universe. In this article, I will confine my discussion to the 90% we don’t understand, dark matter/energy.

The most popular theory of dark matter is that it is a slow-moving particle. It travels up to a tenth of the speed of light. It neither emits nor scatters light. In other words, it is invisible. However, its effects are detectable, as I will explain below. Scientists call the mass associated with dark matter a “WIMP” (Weakly Interacting Massive Particle). Dark matter has a long history, that goes back to 1993. For purposes of brevity, I won’t delineate the history here. However, I want to point out that modern science believes that dark matter is the invisible glue that holds galaxies, like our Milky Way, together. It is an experimentally observed fact that the outer most stars in our galaxy are orbiting at the rate at the inner most stars. If the galaxies followed Newton’s law of gravity, the outermost stars would be thrown into space. This implies that either Newton’s laws do not apply, or that most of the mass of galaxies is invisible, hence the name dark matter. Even in the face of conflicting theories that attempt to explain the phenomena, most scientists believe dark matter is real. None of the conflicting theories (which typically attempted to modify how gravity behaves on the cosmic scale) is able to explain all the observed evidence, especially gravitational lensing (the way gravity bends light).

Currently, the scientific community believes that dark matter is real and abundant, making up as much as 90% of the mass of the universe. However, dark matter is still a mystery. For years, scientists have been working to find the WIMP particle to confirm dark matter’s existence. All efforts have been either unsuccessful or inconclusive.

The above is a brief thumbnail sketch of dark matter. Now, let’s discuss dark energy.

Mainstream science widely accepts the Big Bang as giving birth to our universe. Scientists knew from Hubble’s discovery in 1929 that the universe was expanding. Prior to 1998, scientific wisdom was that the expansion of the universe would gradually slow down, due to the force of gravity. However, in 1998, the High-z Supernova Search Team (an international cosmology collaboration) published a paper that shocked the scientific community. The paper was: Adam G. Riess et al. (Supernova Search Team) (1998). “Observational evidence from supernovae for an accelerating universe and a cosmological constant.” Astronomical J. 116 (3). They reported that the universe was doing the unthinkable. The expansion of the universe was not slowing down—in fact, it was accelerating.

Almost all scientists hold the paradigm of “cause and effect.” If it happens, something is causing it to happen. Things do not simply happen. They have a cause. Therefore, it is perfectly reasonable to believe something is countering the force of gravity, and causing the expansion to accelerate. What is it? No one knows. Science calls it “dark energy.”

That is the state of science as I write this article in April 2015. Galaxies should be flying apart, but they don’t. Science postulates that a slow-moving particle traveling up to a tenth of the speed of light that neither emits nor scatters light is responsible, and they call that particle “dark matter.” However, there is no solid theoretical or experimental evidence to support its existence. The universe’s expansion should be slowing down due to gravitational attraction, but instead it is accelerating. No one knows why. Scientists reason there must be a cause countering the pull of gravity. They name that cause “dark energy.”

Dark matter and dark energy have two things in common. They both have the word “dark” in their name and they are both a mystery to modern science.

The Search for Earth-Like Planets & Extraterrestrial Life

April 18, 2015Categories, Life, Physics, Universe Mysterieslouis del monte, The Search for Earth-Like Planets & Extraterrestrial Lifeadmin

In 1961, Dr. Frank Drake, an American astronomer, and a founder of SETI (search for extraterrestrial intelligence), formulated an equation known as the Drake equation, to calculate the number of intelligent civilizations in our Milky Way galaxy. By multiplying together a series of terms relating to the probability of extraterrestrial life (the rate of star formation in the universe, the fraction of stars with planets, the fraction of planets with conditions suitable for life, etc.), he calculated that the existence of intelligent life on other planets is extremely likely. However, the Drake equation had several serious drawbacks. First, the equation had at least four utterly unknown terms in it, namely 1) the fraction of planets with life, 2) the odds life becomes intelligent, 3) the odds intelligent life becomes detectable, and 4) the detectable lifetime of civilizations. It suffered from a highly questionable premise, namely that advanced alien civilizations arise and die out in their own solar system. Therefore, scientists like Dr. Carl Sagan could optimistically predict over one million advanced alien civilizations in 1966, while other less-optimistic scientists predicted we were alone. All used the same equation, but with different assumptions for the unknowns. As you can imagine, instead of resolving the paradox, it fueled it. In fairness though, the Drake Equation was not proposed as a hypothesis. It was not intended to be proved or disproved. Its main purpose was to fire our imaginations to the possibility that extraterrestrial life may exist in our galaxy.

If we are not alone in the universe, it would be reasonable to assume some extraterrestrial civilizations would more advanced that ours. If intelligent life exists, imagine if they evolved one million years earlier than we did. From a cosmological perspective, one million years is a blink of an eye. Imagine what our capabilities will be a thousand years in the future, assuming humankind exists one thousand years in the future. It is entirely reasonable to assume intelligent life may have gotten an earlier start in the universe, and be scientifically more advanced. This brings us to the Fermi paradox, which poses a deceptively simple question: if the probability of advanced aliens is so high, why haven’t we detected them or been contacted by them? The paradox has to do with the high probability of existence, in this case advanced aliens, and the lack of evidence. Ancient alien theories and Roswell conspiracy theorists notwithstanding, there is no widely accepted scientific proof that aliens have visited the Earth or tried to contact us.

In 1950, employee Enrico Fermi was walking to lunch with his colleagues at Los Alamos National Laboratory. The topic of UFOs came up because of numerous sightings and reports sensationalized by the media. Although the conversation started on a light note, it soon became serious. Fermi and his colleagues began to discuss the possibility of faster-than-light travel, which from Einstein’s special theory of relativity, is impossible. However, if advanced aliens were going to visit the Earth, they would likely need to travel faster than light given the vast distances between interstellar destinations. Although Fermi’s colleagues considered faster-than-light travel a long shot, Fermi believed that science would discover a way to make objects travel faster than light within a decade. He was wrong about that, but his main point was a question. In the middle of lunch, he jumped up and asked, “Where is everybody?” His point, if the universe contains advanced extraterrestrial life, where is the evidence? Fermi began to calculate the potential existence of advanced aliens. His rough calculations indicated that the Earth would have been visited numerous times, from ancient times to the present. This became known as the Fermi Paradox, namely the probability that advanced aliens exist does not square with the lack of evidence.

However, recent discoveries of distant planets that could theoretically harbor life, though, have raised hopes that we might detect extraterrestrials, as our technology to detect them improves and if we just keep looking. Current, scientists estimate there are about 20 billion Earth-like planets in just our galaxy, the Milky Way. When we use the term “Earth-like,” we mean the planet resembles the Earth in three crucial ways:

1) It has to be in an orbit around a star that enables the planet to retain liquid water on one or more portions of its surface. Cosmologists call this type of orbit the “habitable zone.” Liquid water, as opposed to ice or vapor, is crucial to all life on Earth. There might be other forms of life significantly different from what we experience on Earth. However, for our definition of an Earth-like planet, we are confining ourselves to the type of life that we experience on Earth.

2) Its surface temperature must not be too hot or too cold. If it is too hot, the water boils off. If it is too cold, the water turns to ice.

3) Lastly, the planet must be large enough for its gravity to hold an atmosphere. Otherwise, the water will eventually evaporate into space.

In December 2011, NASA’s Kepler (i.e., the Kepler spacecraft) astronomers announced the discovery of the first Earth-like planet, now called “Kepler 22b.” It is about 2.4 times wider than the Earth, and circles a star that is similar to our sun. They estimate Kepler 22b’s average surface temperature to be about 72ºF (degrees Fahrenheit). It is 600 light years from Earth, which cosmologically speaking makes it a near neighbor. The most crucial aspect that makes the planet Earth-like is that it is in the habitable zone.

Today, NASA has confirmed 1,004 planets found, including two that are most Earth-like. The issue now is to determine how to investigate if any of the planets, especially the Earth-like planets, contain life.

Can Galaxies Form New Stars from Nothing?

April 13, 2015Categories, Physics, Universe MysteriesCan Galaxies Form New Stars from Nothing, forming new stars, galactic recycling, Kate Rubin, louis del monte, Max Planck Institute, star formationadmin

In recent years, astronomers have been puzzled by formidable mystery. Galaxies don’t appear to have enough raw material within them to form new stars at the rate they do. The Milky Way, for example, turns about one solar mass’ worth of matter into new stars every year, despite the apparent lack of star forming raw material, such as gas and dust.. Even more perplexing, astronomers believe that galaxies expel gas and dust into outer space due to various processes within the galaxies, such as supernova explosions of dying stars, as well as the force of radiation from bright stars. This would seem to suggest that galaxies are losing star forming material and should be unable to continue to form new starts at the rate they do.

Recently, Kate Rubin of the Max Planck Institute for Astronomy in Germany, leading a team of astronomers, used the Keck I telescope on Mauna Kea in Hawaii to observe 100 galaxies between 5 and 8 billion light-years away from Earth. They made a startling discovery. For six of the galaxies they observed, gas adrift in space was being recaptured by the galaxies and flowing back into their centers. This confirmed a long held suspicion that the gravitational attraction of galaxies would eventually recycle the gases expelled and use it to form new stars.

However, no such observation was made regarding the other 94 galaxies. Astronomers believe this is because it is difficult to detect the gas flow, which is dependent on the orientation of the galaxy. Essentially, they believe galactic recycling is occurring, but they are unable to confirm it. “This is a key piece of the puzzle and important evidence that cosmic recycling (‘galactic fountains’) could indeed solve the mystery of the missing raw matter,” according to a Max Planck Institute for Astronomy statement.

However, before we breakout the champagne, be aware that galactic recycling may not explain the entire mystery. It’s not clear that galaxies are capturing enough material to account for the amount of formation of new starts. Arguably, the most fundamental law in physics is the conservation of energy This suggests that the material to form new stars is coming from some place. If galactic recycling isn’t the total answer, we must look to other possible sources, perhaps even dark matter.

The universe is still extremely mysterious and our understanding has just scratched the surface. Galactic recycling is likely an important piece of the puzzle regarding new star formation. Like all great mysteries in science, it takes time to get and place all the puzzle pieces before the puzzle picture becomes clear.

Where Is All the Lithium?

April 11, 2015Big Bang Science Theory, Categories, Physics, Universe Mysteriesaxions, discrepancy big bang model, Korn, less Lithium in the universe, louis del monte, strong CP problem, Where Is All the Lithiumadmin

According to standard cosmology theory, Lithium, together with hydrogen and helium, is one of three elements to have been synthesized in the Big Bang. Therefore, we should see a uniform abundance of Lithium throughout the universe. However, we don’t. By experimental observation, the older stars seem to have less Lithium than they should (by a factor of 2 or 3), and some younger stars have far more. This discrepancy regarding the uniform abundance of Lithium and experimental analysis of older stars is one of the most distressing discrepancies with the Big Bang theory. In science, one significant discrepancy can dispute a theory. Therefore, this raised serious questions regarding the validity of the Big Bang theory and cast doubt on the accuracy of the experimental measurements.

In 2006, astronomers Andreas Korn of Uppsala University in Sweden and colleagues in Denmark, France and Russia made an important discovery regarding the Lithium cosmic discrepancy. Using a spectrometer on the European Southern Observatory’s Very Large Telescope in Chile, Korn and co-workers studied 18 stars in a distant globular cluster called NGC 6397, which formed roughly a few hundred million years after the Big Bang. Using their experimental data along with theoretical models of how nuclei behave in the atmospheres of stars, they put forward a new model. They hypothesized that the lithium diffuses into the interiors of stars over time, where it is burnt up at temperatures of over 2.5 million Kelvin. Their model suggested that these stars originally contained 78% more lithium than we observe today. In other words, the predicted initial amount of Lithium agrees with predictions from the Big Bang theory.

Even after Korn’s (and colleagues) discovery in 2006, some cosmologists continued to entertained a competing theory, namely that axions, hypothetical subatomic particles, may have absorbed protons and reduced the amount of Lithium created in the period just after the Big Bang. The axion particle was postulated by the Peccei–Quinn theory in 1977 to resolve the “strong CP problem” (CP standing for charge parity). In theoretical physics, quantum chromodynamics (QCD), the theory of strong interactions, predicted there could be a violation of CP symmetry in the strong interactions (the mechanism responsible for the strong nuclear force that holds the nucleus of the atom together). However, there is no experimentally known violation of the CP-symmetry in strong interactions. In effect, cosmologists forwarding the axion theory to explain the cosmological Lithium discrepancy are attempting to explain one mystery (i.e., the cosmological Lithium discrepancy) with another mystery (hypothetical axions). Although, the strong CP problem continues to remain one of the most important unsolved problems in physics, axions appear to be a far less plausible solution to the cosmological Lithium discrepancy. If we apply Occam’s razor (i.e., the simplest of competing theories is preferred to the more complex or that explanations of unknown phenomena be sought first in terms of known quantities), Korn’s (and colleagues) model triumphs.

If we accept Korn’s (and colleagues) model, one of the great cosmological mysteries is resolved and questions regarding the Big Bang model and the experimental measurements are resolved. However, in science old paradigms seem to only die when the scientists holding them die. In my judgement, Korn and his colleagues have resolved the missing Lithium question and are potential candidates for the Nobel Prize.

Image: The Very Large Telescope is a telescope operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile

What Causes Gravity?

April 2, 2015Categories, Physics, Universe MysteriesEinstein general law of relativity, general theory of relativity, graviton, gravity, louis del monte, newton's law of gravity, spacetime curvature, What Causes Gravityadmin

It may be hard to believe that the cause of gravity continues to remain one of the great mysteries of science, even to this day. This article will briefly explore our understanding of gravity.

We are all familiar with the effects of gravity. The story of Newton being hit on the head by an apple leading to his discovery of gravity is often taught to school children. In short, gravity is a natural phenomenon by which all physical bodies attract each other. For example, the Earth attracts you and keeps you grounded. When you weigh yourself, you are actually measuring the effect gravity has on your body. Although this seems obvious, science still continues to debate what causes gravity.

In 1687, English mathematician Sir Isaac Newton published Principia and wrote, “ “I deduced that the forces which keep the planets in their orbs must [be] reciprocally as the squares of their distances from the centers about which they revolve: and thereby compared the force requisite to keep the Moon in her Orb with the force of gravity at the surface of the Earth; and found them answer pretty nearly.” This became known as Newton’s inverse square law of gravity. Although Newton was unable to define the exact nature of the gravitational force, Newton’s law of universal gravitation became widely accepted right up to the beginning of the 20th century. It is often taught in high school science classes and for most applications is a good approximation regarding the behavior of gravity.

In 1915, Einstein published his theory of gravity within the framework of his now famous theory of general relativity. According to general relativity, the effects of gravitation are caused by a spacetime curvature and not a force, as Newton had asserted. Einstein’s theory of general relativity was able to successfully account for several effects that were unexplained by Newton’s law, such as the anomalies in the orbits of Mercury. Einstein’s theory of general relativity proposed that spacetime is curved by matter, and that free-falling objects are moving along locally straight paths, called geodesics, in curved spacetime. A simple way to think about this is to think about a drum. Now think about pushing down in the center of the drum. This would cause the entire surface of the drum to become concave (i.e., curve inward). If you drop a marble on the drum, it will fall to the center due to the inward curvature of the drum’s surface. Although Einstein general theory of relativity is now a corner stone of modern physics, especially astrophysics, it still did not explain fundamentally why or how matter curves space, which still left the nature of gravitation a mystery. On a side note, while general relativity predicted numerous phenomena, such as gravitational lensing (i.e., the bending of light by a large mass) and an effect of gravity on time known as gravitational time dilation (i.e., the slowing down of “clock” in a strong gravitational field), it was incompatible with the highly successful theory of quantum mechanics, which describes the behavior of atoms and subatomic particles.

Where does all this leave us? Currently, there is no widely accepted theory on the fundamental nature of gravity. However, there is no lack of proposed theories. The one that appears to have the most support is string theory. M-theory is the most comprehensive formulation of string theory. In general, M-theory asserts that the fundamental building blocks of all matter can be reduced to infinitely small building blocks of vibrating energy, having only the dimension of length, termed “stings.” Conceptually, the “strings” vibrate in multiple dimensions. The vibration of the string determines whether it appears as matter or energy. According to string theory, every form of matter or energy is the result of the string’s vibration. In addition, M-theory predicts there are eleven dimensions, ten spacial and one temporal, as opposed to the four dimensions implicitly predicted by relativity and quantum mechanics. One of the attractions of string theory is that it fundamentally explains gravity. At this point, you might think we have finally reached a conclusion regarding the nature of gravity, but there are problems. There is no scientific consensus that M-theory correctly describes reality. Its detractors, such as Richard Feynman, Roger Penrose and Sheldon Lee Glashow, have criticized M-theory for not providing experimental predictions at accessible energy scales. In essence, science has been unable to verify M-theory experimentally.

While scientists understand how gravity acts, they do not understand why it exists. For example, why are atoms mostly empty space, instead of being pulled into a solid mass by gravity? Why is the force that holds atoms together different from gravity? Modern physics holds that the gravitational force is mediated by a massless particle called the graviton, which is postulated to travel at the speed of light. However, there is no experimental evidence that the graviton exists. In essence, the effects of gravity have been known for thousands of years, likely by the earliest humans. Laws describing the behavior of gravity have been known for hundreds of years. The exact nature of gravity continues to be controversial.

Is Time Travel Possible?

March 20, 2015Categories, Physics, Time Travel, Universe Mysteriesis time travel possible, louis del monte, time travel to the future, time travel to the pastadmin

Few topics in science capture the imagination like time travel. Science fiction, like H. G. Wells’ classic novel, The Time Machine, published in 1895, and science fact, like time dilation, continues to fuel interest in time travel. Let us start with the most important question: Is time travel possible?

Of course, time travel is possible. We are already doing it. At this point, I know my answer may come across a bit flippant. However, my answer has a kernel of truth. We are traveling in time. We continually travel from the present to the future. This is what philosophers refer to as the arrow of time. In our everyday experience, it moves in one direction, from the present to the future. I think, though, on a more serious note, what people want to know is can we travel back in time—or to a future date in time.

In theory, it is possible. Indeed, numerous solutions to Einstein’s special and general relativity equations predict time travel is possible. In general, no law of physics prohibits time travel. We will begin by considering two methods science proposes to travel in time .

Method 1: Time Travel to the Future – Faster-than-light (FTL)

Using faster than light or near the speed of light, time travel appears to offer methodologies grounded in science fact. Consider two examples:

1) Assume you build a spaceship capable of traveling near the speed of light. With such a spaceship, you literally can travel into the future. This may sound like science fiction, but it is widely accepted as scientific fact. Particle accelerators confirm it. We discussed it when we discussed time dilation and the twin paradox. All you need is the spaceship, and an enormous amount of energy to accelerate it near the speed of light. However, this is an enormous problem. From Einstein’s special theory of relativity, we know that as we begin to accelerate a mass close to the speed of light, it becomes more massive, and approaches infinity. Thus, to accelerate it close to the speed of light, we need an energy source that approaches infinity. Perhaps we would have to learn how to harness the energy of a star, or routinely create matter-antimatter annihilations to create energy. Today’s science is nowhere near that level of sophistication.

2) Assume you can move information (like a signal) faster than light. Theoretically, if we could send a signal from point A to point B faster than the speed of light, it would represent a form of time travel. However, a significant paradox occurs. Here is an example.
An observer A in an inertial frame A sends a signal to an observer B in an inertial frame B. When B receives the signal, B replies and sends a signal back to A faster than the speed of light. Observer A receives the reply before sending the first signal.

In 1907, Albert Einstein described this paradox in a thought experiment to demonstrate that faster-than-light communications can violate causality (the effect occurs before the cause). Albert Einstein and Arnold Sommerfeld in 1910 described a thought experiment using a faster-than-light telegraph to send a signal back in time. In 1910, no faster-than-light signal communication device existed. It still does not exist, but the possibility of its development is increasing. From quantum physics, it appears that certain quantum effects “transmit” instantaneously and, therefore, appear to transmit faster than the speed of light in empty space. One example of this is the quantum states of two “entangled” particles (particles that have physically interacted, and later separated). In quantum physics, the quantum state is the set of mathematical variables that fully describes the physical aspects of a particle at the atomic level. When two particles interact with each other, they appear to form an invisible bond between them. When this happens, they become “entangled.” If we take one of the particles, and separate it from the other, they remain entangled (invisibly connected). If we change the atomic state of one of the entangled particles, the other particle instantaneously changes its state to maintain quantum-state harmony with the other entangled particle. Significant experimental evidence indicates that separated entangled particles can instantaneously transmit information to each other over distances that suggest the information exchange exceeds the speed of light. Initially, scientists criticized the theory of particle entanglement. After its experimental verification, science recognizes entanglement as a valid, fundamental feature of quantum mechanics. Today the focus of the research has changed to utilize its properties as a resource for communication and computation.

Method 2: Time Travel to the Past – Using Wormholes

Scientists have proposed using “wormholes” as a time machine. A wormhole is a theoretical entity in which space-time curvature connects two distant locations (or times). Although we do not have any concrete evidence that wormholes exist, we can infer their existence from Einstein’s general theory of relativity. However, we need more than a wormhole. We need a traversable wormhole. A traversable wormhole is exactly what the name implies. We can move through or send information through it.

If you would like to visualize what a wormhole does, imagine having a piece of paper whose two-dimensional surface represents four-dimensional space-time. Imagine folding the paper so that two points on the surface are connected. I understand that this is a highly simplified representation. In reality, we cannot visualize an actual wormhole. It might even exist in more than four dimensions.

How do we create a traversable wormhole? No one knows, but most scientists believe it would require enormous negative energy. A number of scientists believe the creation of negative energy is possible, based on the study of virtual particles and the Casimir effect.

Assuming we learn how to create a traversable wormhole, how would we use it to travel in time? The traversable wormhole theoretically connects two points in space-time, which implies we could use it to travel in time, as well as space. However, according to the theory of general relativity, it would not be possible to go back in time prior to the creation of the traversable wormhole. This is how physicists like Stephen Hawking explain why we do not see visitors from the future. The reason: the traversable wormhole does not exist yet.

Hard as it may be to believe, most of the scientific community acknowledges that time travel is theoretically possible. If fact, time dilation of subatomic particles provides experimental evidence that time travel to the future is possible, at least for subatomic particle accelerated close to the speed of light. Real science is sometimes stranger than fiction. What do you believe?

A New Theory of Dark Matter

March 1, 2015Categories, Physics, Universe MysteriesA New Theory of Dark Matter, dark matter, louis del monteadmin

In my last post, “What Is Dark Matter,” I mentioned that most of the scientific community accepts the experimental evidence confirming the existence of dark matter. Rightly so, since the experimental evidence of its existence is incontrovertible. Here are the salient facts that experimentally indicate the existence and location of dark matter:

The rotation of stars, planets, and other celestial masses orbit galaxies, like ours, too rapidly relative to their mass and the gravitational pull exerted on them in the galaxy. For example, an outermost star should be orbiting slower than a similar-size star closer to the center of the galaxy, but we observe they are orbiting at the same rate. Based on this observation, the scientific community asserts there is more mass in the galaxy than we are able to observe. The call this mass dark matter.
We can see the effect dark matter has on light. It will bend light the same way ordinary matter bends light. This effect is gravitational lensing. The visible mass is insufficient to account for the gravitational lensing effects we observe. Once again, this suggests more mass than what we can see.
We are able to use the phenomena of gravitational lensing to determine where the missing mass (dark matter) is, and we find it is throughout galaxies. It is as though each galaxy in our universe has an aura of dark matter associated with it. We do not find any dark matter between galaxies.

While it is true that all evidence has led the scientific community to believes that dark matter is real and abundant, making up as much as 90% of the mass of the universe, its true nature is still a mystery. The current theory among the scientific community is that dark matter is a slow-moving particle that travels up to a tenth of the speed of light, and neither emits nor scatters light. In other words, it is invisible. Scientists call the mass associated with dark matter a “WIMP” (Weakly Interacting Massive Particle).

For years, scientists have been working to find the WIMP particle to confirm dark matter’s existence. All efforts have been either unsuccessful or inconclusive. This raises a significant question. Are we on the right track? Is there a WIMP particle? To address this question, let’s consider the experimental evidence:

The Standard Model of particle physics does not predict a WIMP particle. The Standard Model, refined to its current formulation in the mid-1970s, is one of science’s greatest theories. It successfully predicted bottom and top quarks prior to their experimental confirmation in 1977 and 1995, respectively. It predicted the tau neutrino prior to its experimental confirmation in 2000, and the Higgs boson prior to its experimental confirmation in 2012. Modern science holds the Standard Model in such high regard that a number of scientists believe it is a candidate for the theory of everything. Therefore, it is not a little “hiccup” when the Standard Model does not predict the existence of a particle. It is significant, and it might mean that the particle does not exist.
No evidence of the WIMP particle has surfaced from particle accelerator data, including data gather from experiments using the the Large Hadron Collider (LHC). This is particularly concerning since super colliders have successfully given us a glimpse into the early universe, the time frame from which most of the scientific community believes dark matter originated.
To sum it up, all experiments to detect the WIMP particle have to date been unsuccessful, including considerable effort by Stanford University, University of Minnesota and Fermilab.

That is all the experimental evidence we have. Where does this leave us? The evidence is telling us the WIMP particle might not exist. We have spent over a decade, and unknown millions of dollars, which so far leads to a dead end. This appears to beg a new approach.

To kick off the new approach, consider the hypothesis that dark matter is a new form of energy. We know from Einstein’s mass-energy equivalence equation (E = mc²), that mass always implies energy, and energy always implies mass. For example, photons are massless energy particles. Yet, gravitational fields influence them, even though they have no mass. That is because they have energy, and energy, in effect, acts as a virtual mass.

If dark matter is energy, where is it and what is it? Consider these properties of dark-matter energy:

It is not in the visible spectrum, or we would see it.
It does not strongly interact with other forms of energy or matter.
It does exhibit gravitational effects, but does not absorb or emit electromagnetic radiation.

Based on these properties, we should consider M-theory (the unification of all string theories that mathematically suggests there may be ten spacial dimensions, not three, as well as a time dimension). Several prominent physicists, including one of the founders of string theory, Michio Kaku, suggest there may be a solution to M-theory that quantitatively describes dark matter and cosmic inflation. If M-theory can yield a superstring solution, it would go a long way to solving the dark-matter mystery. I know this is like the familiar cartoon of a scientist solving an equation where the caption reads, “then a miracle happens.” However, it is not quite that grim. What I am suggesting is a new line of research and theoretical enquiry. I think the theoretical understanding of dark matter lies in M-theory. The empirical understanding lies in missing-matter experiments.

What is a missing-matter experiment? Scientists are performing missing-matter experiments as I write this book. They involve high-energy particle collisions. By accelerating particles close to the speed of light, and causing particle collisions at those speeds, they account for all the energy and mass pre- and post-collision. If any energy or mass is missing post-collision, the assumption would be it is in one of non-spatial dimensions predicted by M-theory.

Why would this work? M-theory has the potential to give us a theoretical model of dark matter, which we do not have now. Postulating we are dealing with energy, and not particles, would explain why we have not found the WIMP particle. It would also explain why the Standard Model of particle physics doesn’t predict a WIMP particle. Postulating that the energy resides in the non-spatial dimensions of M-theory would explain why we cannot see or detect it, except for its gravitational effects. Why is dark matter able to exhibit gravity,, especially from a hidden dimension? That is still a mystery, as is gravity itself. We have not been able to find the “graviton,” the mysterious particle of gravity that numerous particle physicists believe exists. Yet, we know gravity is real. It is theoretically possible that dark matter (perhaps a new form of energy) and gravity (another form of energy) are both in a different dimension. This framework provides an experimental path to verify both M-theory and the existence of dark matter (via high-energy particle collisions).

This is a conceptual framework, but fits the observations. I am not suggesting we abandon our search for the WIMP particle. However, I suggest we widen our search to include the possibility that dark matter is not a particle, but a new form of energy.

What Is Dark Matter?

February 26, 2015Categories, Physics, Universe Mysteriesdark matter, louis del monte, universe's mysteries, What is dark matter, WIMP particleadmin

Dark matter is real, mysterious, and necessary for our existence. Without it, we would not have a universe. It is a good thing with an ominous-sounding name. So, what is dark matter?

In 1933, Fritz Zwicky (California Institute of Technology) made a crucial observation. He discovered the orbital velocities of galaxies were not following Newton’s law of gravitation (every mass in the universe attracts every other mass with a force inversely proportional to the square of the difference between them). They were orbiting too fast for the visible mass to be held together by gravity. If the galaxies followed Newton’s law of gravity, the outermost stars would be thrown into space. He reasoned there had to be more mass than the eye could see, essentially an unknown and invisible form of mass that was allowing gravity to hold the galaxies together. Zwicky’s calculations revealed that there had to be 400 times more mass in the galaxy clusters than what was visible. This is the mysterious “missing-mass problem.” It is normal to think that this discovery would turn the scientific world on its ear. However, as profound as the discovery turned out to be, progress in understanding the missing mass lags until the 1970s.

In 1975, Vera Rubin and fellow staff member Kent Ford, astronomers at the Department of Terrestrial Magnetism at the Carnegie Institution of Washington, presented findings that reenergized Zwicky’s earlier claim of missing matter. At a meeting of the American Astronomical Society, they announced the finding that most stars in spiral galaxies orbit at roughly the same speed. They made this discovery using a new, sensitive spectrograph (a device that separates an incoming wave into a frequency spectrum). The new spectrograph accurately measured the velocity curve of spiral galaxies. Like Zwicky, they found the spiral velocity of the galaxies was too fast to hold all the stars in place. Using Newton’s law of gravity, the galaxies should be flying apart, but they were not. Presented with this new evidence, the scientific community finally took notice. Their first reaction was to call into question the findings, essentially casting doubt on what Rubin and Ford reported. This is a common and appropriate reaction, until the amount of evidence (typically independent verification) becomes convincing.

In 1980, Rubin and her colleagues published their findings (V. Rubin, N. Thonnard, W. K. Ford, Jr, (1980). “Rotational Properties of 21 Sc Galaxies with a Large Range of Luminosities and Radii from NGC 4605 (R=4kpc) to UGC 2885 (R=122kpc).” Astrophysical Journal 238: 471.). It implied that either Newton’s laws do not apply, or that more than 50% of the mass of galaxies is invisible. Although skepticism abounded, eventually other astronomers confirmed their findings. The experimental evidence had become convincing. “Dark matter,” the invisible mass, dominates most galaxies. Even in the face of conflicting theories that attempt to explain the phenomena observed by Zwicky and Rubin, most scientists believe dark matter is real. None of the conflicting theories (which typically attempted to modify how gravity behaved on the cosmic scale) was able to explain all the observed evidence, especially gravitational lensing (the way gravity bends light).

The Department of Energy Fermi National Accelerator Laboratory Cryogenic Dark Matter Search (CDMS) experiment is ongoing, in an abandoned iron mine about a half mile below the surface, in Soudan, Minnesota. The Fermilab is a half mile under the earth’s surface to filter cosmic rays so the instruments are able to detect elementary particles without the background noise of cosmic rays. In 2009, they reported detecting two events that have characteristics consistent with the particles that physicists believe make up dark matter. They may have detected the WIMP particle. However, they are not making that claim at the time of this writing. The Fermilab stopped short of claiming they had detected dark matter because of the strict criteria that they have self-imposed, specifically there must be less than one chance in a thousand that the event detected was due to a background particle. The two events, although consistent with the detection of dark matter, do not pass that test.

From an article written in Fermilab Today (December 13, 2009), the Fermilab Director Pier Oddone said, “While this result is consistent with dark matter, it is also consistent with backgrounds. In 2010, the collaboration is installing an upgraded detector (SuperCDMS) at Soudan with three times the mass and lower backgrounds than the present detectors. If these two events are indeed a dark matter signal, then the upgraded detector will be able to tell us definitively that we have found a dark matter particle.” As of this writing, Fermilab and other laboratories maintain their quest to find the WIMP particle. To date, we are without conclusive evidence that the WIMP exists.

If it exists, there is a reasonable probability that the WIMP particle can be “created” via experiments involving super colliders (such as the Large Hadron Collider (LHC) built by the European Organization for Nuclear Research (CERN) over a ten-year period from 1998 to 2008). Super colliders have successfully given us a glimpse into the early universe. Since most scientists believe that dark matter exists as part of creation at the instant of the Big Bang, super colliders may provide a reasonable methodology of directly creating dark matter. As of this writing, scientists using the Large Hadron Collider are attempting to create WIMP particles via high-energy proton collisions.

Are we on the right track? Is there a WIMP particle or is dark matter related to something else? We’ll explore the nature of dark matter in more depth in my next post?

Is Time Travel to the Future Possible?

February 21, 2015Categories, Physics, Time Travelhow to time travel, Is Time Travel to the Future Possible, louis del monte, time dilation, time dilation examples, time traveladmin

Since the future doesn’t exist, how would it be possible to travel into the future? This question has been debated by both philosophers and scientists. However, time travel to the future is the only experimental evidence we have of time travel. To understand this, we will need to understand Einstein’s theories of special and general relativity.

The science of time travel was launch in 1905, when Einstein published his special theory of relativity in the prestigious Annalen der Physik (i.e., Annals of Physics), one of the oldest scientific journals (established in 1790). The paper that Einstein submitted regarding his special theory of relativity was titled “On the Electrodynamics of Moving Bodies.” By scientific standards, it was unconventional. It contained little in the way of mathematical formulations or scientific references. Instead, it was written in a conversational style using thought experiments. If you examine the historical context, Einstein had few colleagues in the scientific establishment to bounce ideas off. In fact, Einstein essentially cofounded, along with mathematician Conrad Habicht and close friend Maurice Solovine, a small discussion group, the Olympia Academy, which met on a routine basis at Solovine’s flat to discuss science and philosophy. It is also interesting to note that Einstein’s position as a patent examiner related to questions about transmission of electric signals and electrical-mechanical synchronization of time. Most historians credit Einstein’s early work as a patent examiner with laying the foundation for his thought experiments on the nature of light and the integration of space and time (i.e., spacetime).

Einstein’s special theory of relativity gave us numerous new important insights into reality, among them the famous mass equivalence formula (E = mc²) and the concept and formula for time dilation. Time dilation lays the foundation for forward time travel, so let’s understand it in more depth.

According to special relativity’s time dilation, as a clock moves close to the speed of light, time slows down relative to a clock at rest. The implication is that if you were able to travel in a spaceship that was capable of approaching the speed of light, a one-year round trip journey as measured by you on a clock within the spaceship would be equivalent to approximately ten or more years of Earth time, depending on your exact velocity. In effect, when you return to Earth, you will have traveled to Earth’s future. This is not science fiction. As I mentioned above, time dilation has been experimentally verified using particle accelerators. It is widely considered a science fact.

What scientific experimental evidence do we have that time dilation is real. Here are several experiments that validate time dilation caused when particles move close to the speed of light.

Velocity time dilation experimental evidence:

Rossi and Hall (1941) compared the population of cosmic-ray-produced muons at the top of a six-thousand-foot-high mountain to muons observed at sea level. A muon is a subatomic particle with a negative charge and about two hundred times more massive than an electron. Muons occur naturally when cosmic rays (energetic-charged subatomic particles, like protons, originating in outer space) interact with the atmosphere. Muons, at rest, disintegrate in about 2 x 10^-6 seconds. The mountain chosen by Rossi and Hall was high. The muons should have mostly disintegrated before they reached the ground. Therefore, extremely few muons should have been detected at ground level, versus the top of the mountain. However, their experimental results indicated the muon sample at the base experienced only a moderate reduction. The muons were decaying approximately ten times slower than if they were at rest. They made use of Einstein’s time dilation effect to explain this discrepancy. They attributed the muon’s high speed, with its associated high kinetic energy, to be dilating time.

In 1963, Frisch and Smith once again confirmed the Rossi and Hall experiment, proving beyond doubt that extremely high kinetic energy prolongs a particle’s life.

With the advent of particle accelerators that are capable of moving particles at near light speed, the confirmation of time dilation has become routine. A particle accelerator is a scientific apparatus for accelerating subatomic particles to high velocities by using electric or electromagnetic fields. In 1977, J. Bailey and CERN (European Organization for Nuclear Research) colleagues accelerated muons to within 0.9994% of the speed of light and found their lifetime had been extended by 29.3 times their corresponding rest mass lifetime. (Reference: Bailey, J., et al., Nature 268, 301 [1977] on muon lifetimes and time dilation.) This experiment confirmed the “twin paradox,” whereby a twin makes a journey into space in a near-speed-of-light spaceship and returns home to find he has aged less than his identical twin who stayed on Earth. This means that clocks sent away at near the speed of light and returned near the speed of light to their initial position demonstrate retardation (record less time) with respect to a resting clock.

Time dilation can also occur as a result of gravity. Our understanding of this comes from Einstein’s theory of general relativity. What is the difference between the special and general theory of relativity? Einstein used the term “special” when describing his special theory of relativity because it only applied to inertial frames of reference, which are frames of reference moving at a constant velocity or at rest. It also did not incorporate the effects of gravity. Shortly after the publication of special relativity, Einstein began work to consider how he could integrate gravity and noninertial frames into the theory of relativity. The problem turned out to be monumental, even for Einstein. Starting in 1907, his initial thought experiment considered an observer in free fall. On the surface, this does not sound like it would be a difficult problem for Einstein, given his previous accomplishments. However, it required eight years of work, incorporating numerous false starts, before Einstein was ready to reveal his general theory of relativity.

In November 1915, Einstein presented his general theory of relativity to the Prussian Academy of Science in Berlin. The equations Einstein presented, now known as Einstein’s field equations, describe how matter influences the geometry of space and time. In effect, Einstein’s field equations predicted that matter or energy would cause spacetime to curve. This means that matter or energy has the ability to affect, even distort, space and time. One important aspect prediction of general relativity was that gravitational fields could cause time dilation. Here are some important experiments that prove this aspect of general relativity is correct.

Gravitational time dilation experimental evidence:

In 1959, Pound and Rebka measured a slight redshift in the frequency of light emitted close to the Earth’s surface (where Earth’s gravitational field is higher), versus the frequency of light emitted at a distance farther from the Earth’s surface. The results they measured were within 10% of those predicted by the gravitational time dilation of general relativity.

In 1964, Pound and Snider performed a similar experiment, and their measurements were within 1% predicted by general relativity.

In 1980, the team of Vessot, Levine, Mattison, Blomberg, Hoffman, Nystrom, Farrel, Decher, Eby, Baugher, Watts, Teuber, and Wills published “Test of Relativistic Gravitation with a Space-Borne Hydrogen Maser,” and increased the accuracy of measurement to about 0.01%. In 2010, Chou, Hume, Rosenband, and Wineland published “Optical Clocks and Relativity.” This experiment confirmed gravitational time dilation at a height difference of one meter using optical atomic clocks, which are considered the most accurate types of clocks.

The above discussion provides some insight into time dilation, or what some term time travel to the future. However, is it conclusive? Not to my mind! Although we have numerous experiments that demonstrate time dilation (i.e., forward time travel) involving subatomic particles is real, we have been unable to demonstrate significant human time dilation. By the word “significant,” I mean that it would be noticeable to the humans and other observers involved. To date, some humans, such as astronauts and cosmonauts, have experienced forward time travel (i.e., time dilation) in the order of approximately 1/50^th of a second, which is not noticeable to our human senses. If it were in the order of seconds or minutes, then it would be noticeable. Scientifically speaking, there is no documented significant evidence of human time travel to the future.

To answer the subject question of this post, time travel to the future appears to have a valid scientific and experimental foundation. However, to date the experimental evidence does not include significant (noticeable) human time travel to the future, which leaves the question still unanswered. My own view is that when we develop space craft capable of speeds approaching the speed of light with humans on board, time dilation (time travel to the future) will be conclusively proven.

Is Time Travel to the Past Possible?

February 7, 2015Categories, Physics, Time TravelEinstein's general theory of relativity, how to time travel, Is Time Travel to the Past Possible, louis del monte, time traveladmin

For time travel to the past to be possible would require that the past have a physical reality, namely that it continue to exist. If it did not continue to exist, it would suggest time travel to the past is impossible.

Time travel to the past has it theoretical foundation in Einstein’s special relativity. in the way of background, in November 1915, Einstein presented his general theory of relativity to the Prussian Academy of Science in Berlin. The equations Einstein presented, now known as Einstein’s field equations, describe how matter influences the geometry of space and time. In effect, Einstein’s field equations predicted that matter or energy would cause spacetime to curve. This means that matter or energy has the ability to affect, even distort, space and time.

Many of the predictions of general relativity have been scientifically verified. Two of the most important predictions for our study of time travel are (1) gravitational time dilation and (2) closed timelike curves.

Gravitational time dilation predicts that a clock in a strong gravitational field will run slower than a clock in a weak gravitational field. Therefore, a clock on the surface of Jupiter, a massive gas planet three hundred times larger than the Earth, resulting in a significantly stronger gravitational field, will run much slower than a clock on the surface of the Earth. This phenomenon was first verified on Earth, with clocks at different altitudes from the Earth’s surface. Using atomic clocks, time dilation effects are detectable when the clocks differ in altitude by as little as one meter.

Gravitational time dilation also occurs in accelerating frames of reference (i.e., noninertial frames of reference). According to Einstein’s general theory of relativity, an accelerated frame of reference produces an “inertial force,” also termed a “pseudo force,” that results in the same effect as a gravitational force in an inertial frame of reference. The equivalence of the inertial force in a noninertial frame of reference (i.e., an accelerating frame of reference) to a gravitational force in an inertial frame of reference (i.e., a frame of reference moving at a constant velocity) is termed the equivalence principle. The equivalence principle refers to the equivalence of “inertial mass” and “gravitational mass.” Therefore, a blindfolded person in a rapidly ascending elevator would experience a force equivalent to an increase in gravity, as if standing on a planet more massive than Earth. The blindfolded person would not be able to determine if the force experienced is inertial or gravitational. This effect also holds true for time dilation. Time moves slower in a highly accelerated frame of reference in much the same way it would as if it were in a strong gravitational field. It is important to note, a frame of reference can accelerate in two fundamental ways. It can accelerate along a straight line, or it can accelerate by rotating.

Next, let us discuss closed timelike curves. What is a closed timelike curve? It is an exact solution to Einstein’s general relativity equations demonstrating a particle’s world line (i.e., the path the particle follows in four-dimensional spacetime) is “closed” (i.e., the particle returns to its starting point). Closed timelike curves theoretically suggest the possibility of backward time travel. The particle’s world line is describable by four coordinates at each point along the world line, and when it closes on itself, the four coordinates at the start equal the four coordinates at the end. The particle, conceptually, went back to its past (i.e., the starting point). You can think of this like a horse racetrack. As the horse runs around the track, the horse eventually crosses the finish line, the starting point. If we allow the horse racetrack to represent a world line, then when the horse crosses the finish line, the horse has returned to its past (i.e., the starting point). In the mathematics of general relativity, the starting four coordinates, including the fourth dimensional coordinate that includes a time component, equal the four coordinates at the finish line.

The first person to discover a solution to Einstein’s general relativity equations suggesting closed timelike curves (CTCs) was Austrian American logician, mathematician, and philosopher Kurt Gödel, in 1949. The solution was termed the Gödel metric. Since 1949, numerous other solutions containing CTCs have been found, such as the Tipler cylinder and traversable wormholes, both of which will be discussed in section 3. The numerous solutions to Einstein’s general relativity equations suggest that time travel to the past is theoretically possible. However, the entire scientific community is not in complete agreement on this last point.

The largest issue that physicists have with backward time travel is causality violations (cause and effect), where the effect precedes the cause. These violations of causality are termed “time travel paradoxes.” Some physicists suggest that time travel paradoxes inhibit backward time travel, while other physicists argue that time travel paradoxes can be reconciled, and backward time travel is possible. There is no scientific consensus regarding the reality or practicality of time travel to the past. Although, there are a number of experiments that suggest reverse causality is scientifically possible.

Let us consider a recent experiment that demonstrates reverse causality is not only possible, but a scientific fact. In 2009, physicist John Howell of the University of Rochester and his colleagues devised an experiment that involved passing a laser beam through a prism. The experiment also involved a mirror that moved in extremely small increments via its attachment to a motor. When the laser beam was turned on, part of the beam passed through the prism, and part of the beam bounced off the mirror. After the beam was reflected by the mirror, the Howell team used “weak measurements” (i.e., measurement where the measured system is weakly affected by the measurement device) to measure the angle of deflection. With these measurements, the team was able to determine how much the mirror had moved. This part of the experiment is normal, and in no way suggests reverse causality. However, the Howell team took it to the next level, and this changed history, literally. Here is what they did. They set up two gates to make the reflected mirror measurements. After passing the beam through the first gate, the experimenters always made a measurement. After passing it through the second gate, the experimenters measured the beam only a portion of the time. If they chose not to make the measurement at the second gate, the amplitude of the deflected angle initially measured at the first gate was extremely small. If they chose to make the measurement at the second gate, the deflected angle initially measured at the first gate was amplified by a factor of 100. Somehow, the future measurement influenced the amplitude of the initial measurement. Your first instinct may be to consider this an experimental fluke, but it is not. Physicists Onur Hosten and Paul Kwiat, University of Illinois at Urbana-Champaign, using a beam of polarized light, repeated the experiment. Their results indicated an even larger amplification factor, in the order of 10,000.

The above experiment strongly suggest that the future can influence the past. This implies, the past must continue exist and have a physical reality. If it no longer existed, how could the future influence the past. as the above experiments demonstrate.

This is an exciting time for science. Physical experiments suggest that the past may continue to physically exist. If that is true, then time travel to the past may be possible. The is an old saying in physics, “That which is not forbidden by physical law is compulsory.” The exact origin of the saying is not clearly known, but is often attributed to Murray Gell-Mann (born 15 September 1929), an American physicist who received the 1969 Nobel Prize in Physics for his work on the theory of elementary particles. To my mind, this saying suggests it is only a matter of time before we discover how to time travel to the past.

Louis A. Del Monte

Award Winning Physicist, Author, Featured Speaker, and CEO