Tag Archives: universe’s mysteries

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The Top Five Unsolved Mysteries of Science

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There are numerous unsolved mysteries in science. In this post, I will delineate the top five that I consider the most profound.

  1. What caused the Big Bang? Cosmologist are in strong consensus that the Big Bang resulted in the evolution of the Universe, but there is no scientific consensus as to what caused the Big Bang. There are several theories, including one that I put forward in my book, Unraveling the Universe’s Mysteries. However, none of the current theories, including the one that I forward in my book, have garnered consensus in the scientific community. The origin of the Big Bang is arguably the greatest scientific mystery of all time, and it remains an area of considerable research.
  2. How did life start on Earth? There are two fundamental theories regarding the origin of life on Earth. The first theory, panspermia, holds that life exists throughout the Universe and is distributed by meteoroids, asteroids and planetoids. This theory is compelling, but it still leaves us with another profound question, “How did life originate in the Universe?” There are no widely accepted theories to address that question. The second theory, regarding how life started on Earth, is termed biopoesis. It holds that life forms from inorganic matter through natural processes. This theory is also compelling, but no experimental process has resulted in life forming from inorganic matter. By simple logic, one or even both of these theories is correct. Obviously, in the early Universe, life had to form from inorganic matter. It is also possible that life also started on Earth via the same process. It is also possible that once life formed in the Universe, it was spread by meteoroids, asteroids and planetoids.
  3. What is the nature of time? Some scientists, myself included, argue time is real. This stance suggests that time travel would also be possible. In my book, How to Time Travel, I devote considerable attention to the various philosophies of time and to experiments that suggest time is real. I also delineate experiments that prove time travel to the future is real, as well as experiments that prove reverse causality is real (i.e., literally, the effect precedes the cause). I also delineate experiments that prove that something in the future can alter the past. Some philosophers and scientists argue that time is a mental construct. It is not real. That humans invented time to measure change. If that is true, time travel would not be possible, except in your mind. However, scientific experiments, such as time dilation and reverse causality suggest otherwise. What do you think?
  4. What is the fundamental theory of physics? Modern physics rests on two pillars, The first pillar is Einstein’s theories of relativity. The second pillar is quantum mechanics. Although Einstein’s theories explain phenomena on the macro-scale (i.e., the typical scale we observe in our every day life), it fails to explain phenomena on the quantum level (i.e., the level of atoms and subatomic particles). To explain phenomena on the quantum level we must turn to quantum mechanics. This would be acceptable, except Einstein’s theories of relativity are incompatible with quantum mechanics. They do not come together to adequately explain gravity. Physicists have long sought the “theory of everything.” Some physicists, like world renown cosmologist Stephen Hawking, suggest that M-theory (i.e., the most comprehensive string theory) fits the bill. However, there is no consensus or proof that M-theory is even valid. Until the next Einstein comes along and solves the problem, we don’t have a fundamental theory (i.e., a single unifying theory) of physics.
  5. Does life exist on other planets or is the Earth unique? Almost every scientist agrees that given the vastness of the Universe and the numerous Earth-like planets that have been discovered, there must be life somewhere else in the Universe. Indeed, many believe, myself included, that advanced aliens, similar or more advanced than ourselves, must also exist. However, there has been no definitive publication that proves life exists elsewhere in the Universe. I will refrain from getting into UFOs, government conspiracies and similar material. I don’t refute such theories, but as a scientist I must base my conclusions on definitive evidence. To date, we have no definitive evidence (i.e., widely accepted by the scientific community) regarding life on other planets. However, mathematically, I think life on other planets is a certainty. What do you think?
A vivid blue cosmic scene showing a bright star surrounded by glowing nebulae and countless distant stars.

What Is Dark Energy?

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Is dark energy real or simply a ghost story? Unfortunately, the phenomena we call dark energy is both real and scary. If it plays out on its current course, we are going to be alone, all alone. The billions upon billions of other galaxies holding the promise of planets with life like ours will be gone. The universe will be much like what they taught our grandparents at the beginning of the Twentieth Century. It will consist of the Milky Way galaxy. All the other galaxies will have moved beyond our cosmological horizon, and be lost to us forever. There will be no evidence that the Big Bang ever occurred.

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. However, prior to 1998, scientific wisdom was that the expansion of the universe would gradually slow down, due to the force of gravity. We were so sure, so we decided to confirm our theory by measuring it. Can you imagine our reaction when our first measurement did not confirm our paradigm, namely that the expansion of the universe should be slowing down?

What happened 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. Of course, this caused a significant ripple in the scientific community. Scientists went back to Einstein’s general theory of relativity and resurrected the “cosmological constant,” which Einstein had arbitrarily added to his equations to prove the universe was eternal and not expanding. Previous chapters noted that Einstein considered the cosmological constant his “greatest blunder” when Edwin Hubble, in 1929, proved the universe was expanding.

Through high school-level mathematical manipulation, scientists moved Einstein’s cosmological constant from one side of the equation to the other. With this change, the cosmological constant no longer acted to keep expansion in balance to result in a static universe. In this new formulation, Einstein’s “greatest blunder,” the cosmological constant, mathematically models the acceleration of the universe. Mathematically this may work, and model the accelerated expansion of the universe. However, it does not give us insight into what is causing the expansion.

The one thing that you need to know is that 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. That means every bubble in the ocean has a cause. It would be a fool’s errand to attempt to find the cause for each bubble. Yet, I believe, as do almost all of my colleagues, each bubble has 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 book in the latter half of 2012. The universe’s expansion is accelerating. No one knows why. Scientists reason there must be a cause countering the pull of gravity. They name that cause “dark energy.” Scientists mathematically manipulate Einstein’s self-admitted “greatest blunder,” the “cosmological constant,” to model the accelerated expansion of the universe.

Here is the scary part. In time, we will be entirely alone in the galaxy. The accelerated expansion of space will cause all other galaxies to move beyond our cosmological horizon. When this happens, our universe will consist of the Milky Way. The Milky Way galaxy will continue to exist, but as far out as our best telescopes will be able to observe, no other galaxies will be visible to us. What they taught our grandparents will have come true. The universe will be the Milky Way and nothing else. All evidence of the Big Bang will be gone. All evidence of dark energy will be gone. Space will grow colder, almost devoid of all heat, as the rest of the universe moves beyond our cosmological horizon. The entire Milky Way galaxy will grow cold. Our planet, if it still exists, will end in ice. How is that for a scary story?

Microscopic view of a network of blue fluorescent neurons or cells interconnected by fine filaments.

What Is Dark Matter?

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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?

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).

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).

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 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?

Nature of Light

Can Anything Travel Faster Than the Speed of Light?

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Can anything travel faster than the speed of light? To answer this question, let us understand the nature of light. Here are three salient facts about light:

1. First, light can exhibit both the properties of a wave and a particle. For all of the Nineteenth Century, and for the early part of the Twentieth Century, most scientists considered light “a wave,” and most of the experimental data supported that “theory.” However, classical physics could not explain black-body radiation (the emission of light due to an object’s heat). A light bulb is a perfect example of black-body radiation. The wave theory of light failed to describe the energy (frequency) of light emitted from a black body. The energy of light is directly proportional to its frequency. To understand the concept of frequency, consider the number of ocean waves that reach the shore in a given length of time. The number of ocean waves than reach the shore, divided by the length of time you measure them, is their frequency. If we consider the wave nature of light, the higher the frequency, the higher the energy.

In 1900, Max Planck hypothesized that the energy (frequency) of light emitted by the black body, depended on the temperature of the black body. When the black body was heated to a given temperature, it emitted a “quantum” of light (light with a specific frequency). This was the beginning of Quantum Mechanics. Max Planck had intentionally proposed a quantum theory to deal with black-body radiation. To Planck’s dismay, this implied that light was a particle (the quantum of light later became known as the photon in 1925). Planck rejected the particle theory of light, and dismissed his own theory as a limited approximation that did not represent the reality of light. At the time, most of the scientific community agreed with him.

If not for Albert Einstein, the wave theory of light would have prevailed. In 1905, Einstein used Max Planck’s black-body model to solve a scientific problem known as the photoelectric effect. In 1905, the photoelectric effect was one of the great unsolved mysteries of science. First discovered in 1887 by Heinrich Hertz, the photoelectric effect referred to the phenomena that electrons are emitted from metals and non-metallic solids, as well as liquids or gases, when they absorb energy from light. The mystery was that the energy of the ejected electrons did not depend on the intensity of the light, but on its frequency. If a small amount of low-frequency light shines on a metal, the metal ejects a few low-energy electrons. If an intense beam of low-frequency light shines on the same metal, the metal ejects even more electrons. However, although there are more of them, they possess the same low energy. To get high-energy electrons, we need to shine high-frequency light on the metal. Einstein used Max Planck’s black-body model of energy, and postulated that light, at a given frequency, could solely transfer energy to matter in integer (discrete number) multiples of energy. In other words, light transferred energy to matter in discrete packets of energy. The energy of the packet determines the energy of the electron that the metal emits. This revolutionary suggestion of quantized light solved the photoelectric mystery, and won Einstein the Nobel Prize in 1921. You may be surprised to learn that Albert Einstein won the Nobel Prize for his work on quantizing light—and not on his more famous theory of relativity.

2. Second, the speed of light in a vacuum sets the speed limit in the universe. Nothing with a (rest) mass travels faster than light in a vacuum. In addition, this is a constant, independent of the speed of the source emitting the light. This means that the light source can be at rest or moving, and the speed of light will always be the same in a vacuum. This is counterintuitive. If you are in an open-top convertible car speeding down the highway, and your hat flies off, it begins to move at the same speed as the car. It typically will fall behind the car due to wind resistance that slows down its speed. If you are in the same car, and throw a ball ahead of the car, its velocity will be equal to the speed of the car, plus the velocity at which you throw it. For example, if you can throw a ball sixty miles per hour and the car is going sixty miles per hour, the velocity of the ball will be one hundred twenty miles per hour. This is faster than any major league pitcher can throw a fastball. Next, imagine you are in the same car and have a flashlight. Whether the car is speeding down the highway or parked, the speed of light from the flashlight remains constant (if we pretend the car is in a vacuum). The most elegant theory of all time, Einstein’s special theory of relativity, uses this property of light as a fundamental pillar in its formulation.

3. Third, the quanta of light have no rest mass. This last property of light may explain why light in a vacuum sets the upper limit of speed in the universe. According to Einstein’s theory of special relativity, any object with (rest) mass becomes infinitely massive as it approaches the speed of light. By inference we can argue that it would take infinite energy to accelerate a mass to the speed of light.

However, there are other physical entities that have speeds that may equal or even exceed the speed of light. For example, the universe is considered to be expanding faster than the speed of light by numerous cosmologists. Another physical process known as quantum entanglement may also take place at or even faster than the speed of light. Quantum entanglement refers to two particles (photons, for example) which interact and become entangled, such that even when separated the quantum state of one particle will dictate the quantum state of the other particle. For example, if one photon has an angular momentum defined as spin up, the other particle will have an angular momentum of spin down, to conserve spin. If you change the angular momentum of either particle, the other particle appears to instantaneously change, such that they continue to conserve spin. The effects of gravity also appear to propagate at the speed of light. Today, science still questions the nature of gravity. In classic physics, gravity was thought of as an invisible field between two or more masses. However, some physicists speculate the existence of a particle called a graviton, which is a hypothetical elementary particle that mediates the force of gravitation. If gravitons exist, physicists speculate that they travel at the speed of light.

What does all this mean? Basically, it means that light (photons) may not be the only entities that travel at the speed of light in a vacuum.

A row of large white satellite dishes under a partly cloudy sky in an open field.

Searching for Radio Emissions from Advanced Aliens

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Since our discovery of the radio in 1895, we have been beaming radio transmissions into space. Most scientists believe the invention of the radio and radio telescopes would be a natural technological evolution by any intelligent life. Therefore, it would be reasonable to conclude that advanced aliens may have transmitted proof of their existence. The timeframe of their transmissions would depend on when they evolved. If their evolution were concurrent with ours, their transmissions would have started about a century ago. However, if they evolved millions of years ahead of us, their transmissions could have started millions of years ago.

In fact, the whole notion of listening for radio transmissions from aliens dates back to 1896, when Nikola Tesla promoted the idea that the radio could be used to contact advanced extraterrestrial life. In the early 1900s, Guglielmo Marconi, the inventor of the radio, claimed to have picked up Martian radio signals. Other iconic scientists, like Lord Kelvin, credited with inventing the telegraph, added fuel to the radio search for advanced aliens by publicly stating that the radio represented a possible way to detect and even contact them.

When scientists of the stature of Tesla, Marconi, and Kelvin speak, the world listens. In 1924, Mars was closer to Earth than any time in the last 100 years before or since. Obviously, this would be an excellent time to listen for radio transmissions from Mars. To avoid cluttering the Martian signals with our own, a “National Radio Silence Day” was promoted by the United States. For a 36-hour period, during August 21-23, 1924, all radios were silent for five minutes at the beginning of each hour. Concurrently, a dirigible was used to lift a radio up in order to receive signals 3 kilometers above the United States Naval Observatory. A select few listened, including the chief cryptographer of the U.S. Army, William F. Friedman. No radio transmissions from Mars were reported.

The most famous human enterprise listening for alien radio transmissions is SETI, which is not a single organization, but rather a group of organizations that employ radio technology to search for advanced extraterrestrial life. This includes Harvard University, the University of California, Berkeley, and the SETI Institute. Astronomer Frank Drake, using a small radio telescope, undertook the first SETI experiment in 1960. In 1961, the first SETI conference was held at Green Bank, West Virginia. From this humble beginning, SETI was launched. It is still highly active in its search for extraterrestrial radio transmissions as of this writing.

SETI technology has improved vastly. They are searching more frequencies than ever before. However, to date we have no confirmable evidence. SETI researchers have intercepted signals twice, once in 1977 and once in 2003, that may have been alien in nature, but they were not able to confirm the results. In fact, after more than five decades of searching, no confirmable radio transmission evidence of advanced aliens exists. However, to be fair to SETI, we need to examine their two greatest obstacles.

1.    Scale Problems—The universe is enormous, and SETI has had to confine its search to sun-like solar systems within about 200 light years of Earth. Our galaxy is about 100,000 light years across. This may appear as if they have examined about 20% of our galaxy, but that would be incorrect. They focus on high-probability solar systems (ones similar to our own), and thinly slice space looking for the radio transmission. Therefore, the real number is much less than 20%. If it is viewed in terms of the volume, SETI has covered one-fifteen millionth of our own Milky Way galaxy. This, however, is likely to improve. If we add the recent upgrades that SETI made in 2007, namely the Allen Telescope Array, located in northern California, SETI is able to extend its search radius to 25,000 light years. This enables SETI to examine the 40 billion solar systems closer to the center of our galaxy. Still though, we are looking for a needle in a very large galactic haystack.

2.    Technical Hurdles—Our transmitted radio and television signals disperse relatively rapidly in space. They would require extremely sensitive radio telescopes to detect. To understand this, imagine someone holding a candle at night a few feet from you. You are able to see it clearly. This is because numerous photons from the candle are reaching your eyes. Next, imagine that person moves farther away from you. The farther away the person moves, the dimmer the candle becomes. After a while, you will not be able to see the candle at all. The photons of the candle spread out over distance. Initially, when you were close to the candle, numerous photons reached your eyes. As the candle moved farther away, the photons spread out over a larger area, and fewer of them reach your eyes. This is why the candle became dimmer. Eventually, the candle was so far away, too few photons were reaching your eyes for your eyes to sense them.

SETI estimates that even with a sensitive radio telescope, as the extremely large Arecibo Observatory radio telescope in Puerto Rico, the Earth’s radio and televisions transmissions would only be detectable at a distance within 0.3 light years. Therefore, unless the advanced aliens used highly directed transmissions, we would likely not detect them. In addition, if the advanced aliens compressed their data, similar to data downloads from the Internet, the compressed data would appear as noise to us. In addition, advanced aliens may be using frequencies we are not monitoring or do not penetrate our atmosphere. The list of technical hurdles is numerous. Their sheer number and complexity has cast doubt on the entire SETI methodology. Critics believe the SETI efforts are futile, since the technical hurdles regarding the interception of advanced alien radio transmissions are enormous.

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