Tag Archives: universe

Horizons Out of Reach

Imagine you are walking on a terrain of rolling hills; in the distance you can see the horizon. Beyond that point you don’t know what you’ll find. When you arrive at the crest of a hill a whole new landscape appears with its own horizon. This is a common metaphor used to show how knowledge is usually acquired. Each horizon reached often presents another horizon (or question) in the distance.

The story of science is one of impressive discoveries. Many horizons have been reached, but many more are yet to be encountered. No one knows how far we can go and what we will find. I hesitate to limit what might be possible, because science has surprised us time and time again. If the human race survives long enough, is there anything we can’t find out? I would think that there are some questions we will not be able to answer, but which ones? One should think long and hard before ruling anything out, which I have done. For what it’s worth, I am left with two questions which appear out of reach. I’ll get back to this later but first a little context.

Horizons Reached

At present the knowledge base is immense, but it had to be acquired. Imagine going back 100, 500 or 1,000 years and contemplating the future. It’s possible that some future discoveries could have been predicted. However, there are other findings that few saw coming. It is practically impossible to provide a full account of impressive scientific discoveries. However, there are some that immediately stand out. What follows has been mentioned in prior blogs of mine; think of it as a short list of scientific highlights:

  1. The Idea of Natural laws: At around 500 BC the ancient Greeks documented the concept of natural laws. They suggested that patterns in nature could be recognized and attributed to natural laws. This was a major breakthrough in scientific thought.
  2. The Copernican Revolution: In 1543 Nicolaus Copernicus published his theory of the heliocentric model of the universe. He removed the Earth from the center of the known universe and replaced it with the Sun. This was a significant reality check, which would influence human philosophy for years to come.
  3.   Newton’s Laws: In 1687 Isaac Newton disclosed his law of universal gravitation and his three laws of motion. Newton laid the foundation for what later became known as classical physics. Now over 300 years later, Newton’s equations still apply (except for extreme circumstances).
  4. Einstein’s Relativity: With special relativity (in 1905) and general relativity (in 1915), Albert Einstein filed in the gaps in Newton’s laws. Einstein accounted for those extreme circumstances. His contribution led to a greater understanding of the large-scale universe.
  5. Darwin’s Theory of Evolution: Charles Darwin provided an explanation for how all life evolves with his famous publication in 1859. This one basically speaks for itself; few if any discovery is more impressive.
  6. Revealing the Atomic and Subatomic Realm: Beginning in the early 1900s, several people worked on theories such as quantum mechanics and the standard model of partial physics. A realm previously inaccessible was shown to be real and would unwittingly have a significant impact on human affairs.
  7. The Big Bang: In the 1931 George Lemaitre suggested that the universe began in a single geometric point. He arrived at this by applying general relativity to the observations of William Hubble. Lemaitre`s idea would eventually provide us with a truly universal origin story. 
  8. DNA: In 1962 James Watson, Francis Crick and Maurice Wilkins won a Nobel Prize in medicine for the discovery of the structure of DNA. This opened up a whole new science, which will undoubtedly impact us for generations.

Of course the list above could be significantly longer and still fall short. However, I present it just to give you a feel for how knowledge, particularly scientific knowledge, alters our perception of the world. It is debatable how many past discoveries could have been foreseen; nonetheless one can imagine some horizons in the distance which may be attainable. For example: figuring out how life on Earth began, or the discovery of life elsewhere in the universe. Closer to home, there is finding a cure for cancer (or most cancers), and maybe even weather forecasting weeks or months in advance. No one knows for sure which findings are coming, but I feel fairly certain that at least two questions will remain unanswered.

Contemplating the Unanswerable

The two questions I am referring to are as follows: 1) Why is there a universe in the first place?  2) Why is the universe the way it is and not some other way? Another question which I feel I must address before moving on to question 1, is this: Why is there something rather than nothing? You’ve probably heard this one before, and it is similar to question 1. However, I find it to be a peculiar question and here’s why. First let’s define what is meant by nothing. If by nothing, one assumes the absence of everything, then nothing is a non-entity. In other words, how can nothing be a reality if by definition nothing has no existence. The question gives us two options, something or nothing and it seems to me that something is real and nothing is not. By this logic one could conclude that there has to be something, but why a universe?

For some the existence of the universe doesn’t seem to be a big problem to solve. The standard answer is that God created the universe and that’s it. However, I can’t help but ask two simple follow-up questions: a) Why is there a God in the first place? b) Why is God the way he (she, it) is and not some other way? Do you see how this works, by inserting God as the explanation for the universe we’ve circled back to where we started. In essence the questions are identical. We have merely moved the starting point from the universe to God.

Another approach is to examine the possibility of a multiverse. There are scientific reasons that suggest that other universes may exist, but that is as far as it goes.  Although the multiverse is theoretical, it may shed light on question 2. Why is the universe the way it is and not some other way? If multiple universes actually exist, it could be that all possible universes exist, therefore it is not surprising that at least one universe is like ours. Although the multiverse idea is somewhat satisfying on the surface, it has its problems. For starters, it does not address question 1. Why is there a universe in the first place? It says nothing on why there would be a multiverse in the first place.

There is also the problem of testing the multiverse idea scientifically. How can we ever verify something outside the boundaries of our vast universe? Hypothetically, even if our science advanced to a point where universes outside our own could be detected, how could we know the full-scale of a multiverse? We would likely be unable to determine how many universes exist in total. Ultimately that’s where I think the multiverse idea falls short in terms of answering question 2. Why is the universe the way it is and not some other way? If we can’t know how many universes exist in total, we can’t explain why our universe is the way it is and not some other way. All possible universes have to exist in order for the multiverse to the job. Or at the very least, it would take an extremely high number of universes.

Why is there a universe in the first place and why is the universe the way it is and not some other way? I have thought about these two questions philosophically, religiously and scientifically and have made little progress. Each approach gains momentum only to fall short. There are undoubtedly still many horizons within our reach and it will be interesting to see what lies ahead. That being said, I have to conclude that there are at least two horizons that seem to be hopelessly out of reach.

References:http://www.bbc.co.uk/schools/gcsebitesize/science/add_edexcel/cells/dnarev3.shtml

https://www.quora.com/What-is-the-relationship-between-the-Standard-model-and-Quantum-field-theory


 

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The Anthropic Principle

the astronomerWhy are we here? This is perhaps the most fundamental philosophical question. One can imagine contemplating this question at any time in human history. Many stories have been inspired by this question, usually taking the form of myths, or religious and spiritual traditions. Today, ‘why are we here’ is also a scientific question. The anthropic principle arose as a response to the question of human existence. The idea was first proposed in 1973 by theoretical astrophysicist Brandon Carter. Since then it has been expanded and stated in several forms.

What is the Anthropic Principle?

The word anthropic is defined by the Merriam-Webster online dictionary as: “Of or relating to human beings or the period of their existence on Earth.” That’s a start. For simplicity I will stick close to Brandon Carter’s original formulation, which he expressed as two variants. I will paraphrase based on the description from a few sources:

  1. The Weak Anthropic Principle refers to our special location in the universe (both in time and space), which is conducive to our existence. The fact that we can observe the universe means that planet Earth must have the conditions necessary for our existence.
  2. The Strong Anthropic Principle refers to the fundamental laws of physics, which are precisely set for our existence. The strong principle takes into account the properties of the universe as a whole.

The Burden of Proof

habitable zoneIn a vast universe it is not surprising that a planet, like the Earth, has a special location (usually called a habitable zone or a Goldilocks zone). The specific laws of the universe needed for human life are more difficult to explain (usually called fine tuning). Using a legal metaphor, the strong anthropic principle has a greater burden of proof than the weak anthropic principle. In this case, burden of proof is a figure of speech, because the anthropic principle is as much a philosophical idea as a scientific one. 

In The Grand Design, Stephen Hawking and Leonard Mlodinow describe the weak anthropic principle as an environmental factor. They write:

“Environmental coincidences are easy to understand because ours is only one cosmic habitat among many that exist in the universe, and we obviously must exist in a habitat that supports life”

The strong anthropic principle is all-encompassing and generally more controversial. Hawkings and Mlodinow go on:

“The strong anthropic principle suggests that the fact that we exist imposes constraints not just on our environment but on the possible form and content of the laws of nature themselves”

Stating the Obvious or a Profound Insight

Is the anthropic principle a satisfying explanation? On the surface, it seems like an obvious statement that explains very little. But as I reflect on the idea, I am not so sure. Maybe it is suggesting something profound. Perhaps the answer to why we are here is simple: it could not be otherwise.

Lawrence KraussFor example, Lawrence Krauss provides an anthropic interpretation to one of the universe’s properties. In the book, A Universe from Nothing, he examines the relationship between the energy density of matter and the energy density of empty space. Yes, space has energy and it can be measured. The density of matter in the universe can also be measured. It turns out that now is the only time in cosmic history that both values are comparable. That’s a curious result.

The universe has been expanding since the big bang, and as it expands the density of matter decreases. Matter gets diluted as galaxies get farther apart from each other. Meanwhile the energy in empty space remains constant (there is nothing to dilute or increase in empty space). Therefore at the time galaxies formed the density of matter was greater than the energy in empty space. That’s a good thing, because the gravitational effect of matter was dominant, which allowed matter to come together.

However, if the values for matter and energy had been comparable at the epoch of galaxy formation, galaxies would not have formed. Empty space exerts a repulsive force, which would have canceled out normal attractive gravity. Matter would not have clumped together. Krauss writes in A Universe from Nothing:

“But if galaxies hadn’t formed, then stars wouldn’t have formed. And if stars hadn’t formed, planets wouldn’t have formed. And if planets hadn’t formed, then astronomers wouldn’t have formed!”

It seems highly coincidental that the energy values for matter and space are roughly equal now, but they could not have equalized too much earlier. Otherwise, no one would be here to observe it. Similarly, if one of a number of physical properties were slightly different, we would also not be here. That’s when anthropic reasoning steps in: An observer must observe the conditions of the universe that allows the observer to exist.

astronomersMaybe a change of perspective is needed: Instead of focusing on our present circumstances and looking back, we can look at the evolution of the universe. Life is a latecomer to the process, of which an incalculable series of events occurred. Our existence is the result of all that came before. Although it does appear that the universe was made for us, it is in fact, the universe that made us. We were formed from the conditions that were set long before conscious beings could observe any of it.

Is Physics an Environmental Science?

The traditional approach of physics is to discover and understand the universe we live in. The fundamental laws and the values for the constants of nature are consistent throughout the observable universe. The physical laws discovered on Earth can be applied to the universe as a whole. But there can only be one exact set of laws and history that allow for our existence. That’s unless our universe is not the only one.

For some, recent scientific evidence is suggesting that there are many universes (a multiverse). Others point out that inferring a multiverse is not science; because by definition other universes cannot be observed directly (they would exist outside our observable universe). If we apply the strong anthropic principle to the multiverse theme, it does partly explain the exact parameters of our universe.

If the cosmos is populated with many universes, possibly infinite universes, then the laws of physics could be purely random. They would simply emerge as an environmental consequence. Some physicists have compared the multiverse to a foam of bubbles (each bubble representing a universe). The laws could be different in every bubble of an endless cosmic foam. Some bubble universes could be similar to ours, others vastly different.

Of course, this is a hypothetical argument. Nevertheless, if we could observe every universe in a multiverse, every single one would be finely tuned for its own existence. Anthropic reasoning would state that there is nothing special about our universe. In all the non-life generating universes there is no one to observe them, in ours there is. It’s that simple. Obviously, the anthropic principle (inferring a multiverse or not) is not a proven argument, but it’s one of many possible answers to the question: Why are we here?

 

References: Stephen W. Hawking and Leonard Mlodinow, The Grand Design (New York: Bantam Books, 2010), 155.

Lawrence M. Krauss, A Universe from Nothing (New York: Free Press, 2012).


 

Nature’s Fine Tuning and the Multiverse

numbersThere are a number of fundamental physical constants of nature, in which their values seem to be finely tuned. Examples of  such constants are: the speed of light, the strength of gravity, the mass of the elementary particles, and the strength of the atomic forces. The fine-tuning angle comes into play when one considers the exact parameters of the constants. Hypothetically, if one were to adjust the values just a little bit, the universe would be vastly different. This fact alone does not present a problem. However, physicists have noted that minor changes to the values of the constants would not allow life to develop. It is as if the universe knew we were coming, or is it?

The values of the physical constants are critical for giving our universe the structure that it has. For example: the precise strength needed to hold the atomic particles together in stable arrangements, and the gravitational force needed to clump matter into stars and planets. If the strength of gravity was slightly weaker, matter in the early universe would have spread apart too quickly; thus preventing stars from forming. Conversely, if the gravitational force was a little stronger, matter would have come together too quickly and everything would have collapsed. It is clear to scientists that gravity, as well as other values, could not be adjusted very much without erasing the possibility for life.

The Most Extreme Fine Tuning

Although the apparent fine tuning of the constants demand an explanation, nothing compares to the level of fine tuning of one particular constant. This is called the cosmological constant (also called dark energy), and it represents the value of the energy in empty space. The cosmological constant is believed to exert an outward force, which is causing the universe to expand at an accelerated rate. In 1998, the value of the cosmological constant was measured by two teams of astronomers. The number they came up with is extremely small, a decimal point followed by 122 zeros and a one (measured in Planck units).

The energy in empty space, represented by the cosmological constant, is only relevant at the largest of scales. As the universe expands the amount of space is also increasing, thus increasing the effect of the dark energy. But in the distant past when the universe was much smaller, the total energy in space would have produced a far lesser effect. And here is the catch. If the outward push of the cosmological constant was slightly larger by a few decimal points, it would have counteracted the pull of gravity too quickly. This would have prevented stars, planets and galaxies from forming. In this scenario life would not exist.

By removing just a few zeros from an already small value, a universe suitable for life would disappear. Physicists are at a loss to explain why the number is so small and so finely tuned for our existence. In addition, the value of the cosmological constant revealed by observations is far less that what theory predicts. That is, the theory of the microscopic realm (quantum mechanics) predicts that the energy in empty space should be much larger. The mismatch between theory and observation does not sit well with physicists, as it shows that there is something missing with this picture.

Possible Solutions

The specific values of the physical constants require an explanation. Some people will look for a metaphysical solution. This will usually imply a creator for the universe who setup the constants for a purpose. The word God is the preferred choice, and it suggests that the universe was planned for our existence. Yet for others, crediting God for designing the universe in a special way is a non-explanation. One would still have to explain where God came from and why he was there in the first place.

Another line of reasoning would be to accept that mere chance accounts for the constants. But given the amount of fine tuning, this seems akin to winning a lottery with an infinite number of combinations. Chance alone is not a very satisfying solution. There is also the possibility that we don’t have enough information to solve the problem. Maybe a deeper understanding of the laws of physics is needed, and someday physicists will find the answer.

 The Multiple Universe Proposal

multiverseThe word universe has traditionally been used to describe all that exists. However, cutting-edge physics is requiring that a change of perspective is needed. Through a variety of physical discoveries the idea of multiple universes is being considered. The words parallel universes, parallel worlds, alternate universes, multiverse and others are being used. In the multiple-universe theme, the word universe has a slightly different meaning. Universe no longer means all there is, but rather means a region of a larger cosmos that is separated from other regions.

Physicist and science writer Brian Greene states, in The Hidden Reality, why the concept of multiple universes is compelling:

” The subject of parallel universes is highly speculative. No experiment or observation has established that any version of the idea is realized in nature… That said, I find it both curious and compelling that numerous developments in physics, if followed sufficiently far, bump into some variation on the parallel-universe theme.”

Although not yet experimentally tested, having large numbers of universes (possibly infinite) could explain the fine tuning of the physical constants. The logic is simple. With many universes, with different possible values for the constants, it is likely that one has the values we observe. Therefore, it is not surprising that we find ourselves in a universe that allows life. In the universes that have conditions that don’t allow life, there is no one to observe them, no one to say that they are not finely tuned for life.

As Brian Greene suggested, there are several theories in physics that imply a multiverse. The reasoning is technical, though I will list a few examples, which point to the possibility of a multiverse:

  • Eternal Cosmological Inflation: The extreme burst of spatial expansion at the early moments of the universe is known as inflation. Inflation is a cosmological principle, which in theory could happen anywhere, thus giving rise to multiple big bangs.
  •  A Spatially Infinite Cosmos: By inferring an infinite expanse of space-time, there is a limit to ways particles of matter can be arranged. Conditions in one location would eventually have to repeat somewhere else, creating parallel universes.
  •  The Extra Dimensions of String Theory: String theory proposes that at the tiniest of scales there exist extra spatial dimensions. It also states that there are many possible shapes for the extra dimensions of space. However, string theory cannot determine which of the shapes corresponds to our universe. If string theory is correct, the different possible shapes for these extra dimensions could be realized in different universes.
  • The Many-Worlds Interpretation of Quantum Mechanics: The atomic/subatomic realm is governed by randomness and understood using probabilities. Interpretations can vary. The many-worlds interpretation states that all the possible outcomes associated with quantum mechanical probabilities really happen, resulting in parallel worlds.

parrallel universeNot all the multiple universe proposals would yield different values for the constants. Some would produce exact replicas of our universe, or very close copies. Hence the term parallel universe. Yet other proposals would allow for different laws of physics or different values for the constants. These could be universes that are totally foreign and barely recognizable to us.

Whether we live in one of multiple universes is anyone’s guess. Presently, there is no known method that could observe them. Nevertheless, there are plenty of cases where physical theories or mathematics have pointed toward a phenomenon in nature, even before it was observed. And then at some later date, observations confirmed the theory. Therefore, if modern physics is suggesting the existence of a multiverse, it provides an interesting argument for the fine tuning of the physical constants of nature.

 

References: Brian Greene, The Hidden Reality (New York: Alfred A. Knopf, 2011), 8, 9.

Leonard Susskind – Is the Universe Fine-Tuned for Life and Mind? (Closer to Truth), Published on Jan 8, 2013. https://www.youtube.com/watch?v=2cT4zZIHR3s

 The Fabric of the Cosmos – Universe or Multiverse (Published on July 16, 2014) https://www.youtube.com/watch?v=ib0RNqVusoU


 

The Cosmological Constant: From Einstein to Dark Energy

EinsteinThe cosmological constant has its humble beginnings with Albert Einstein’s theory of gravity. In 1915, after a decade of working on some unsolved issues regarding gravity, Einstein completed the theory of general relativity. Today, this is still the best theory we have for describing how gravity works at large scales. Nevertheless, 2 years later (in 1917) Einstein made a small adjustment to the equations of general relativity. He introduced a term called the cosmological constant, which represented a repulsive force to counteract the attractive force of gravity.

Einstein realized that general relativity would require the universe to either be expanding or contracting, however, the belief at the time was that the universe was essentially static and eternal. Because gravity causes large structures to attract each other, logic would deduce that the universe as a whole should be contracting. But this was neither observed nor part of conventional thinking. The cosmological constant, a repulsive force with just the right value, allowed the universe to remain static. Although the cosmological constant was present in all of space, Einstein provided little details concerning what this mysterious force actually was.

Einstein’s Greatest Blunder

In 1929, Edwin Hubble carefully studied light from distant galaxies. He calculated the distance of the galaxies by examining the luminosity of a specific type of star, known as a Cepheid variable. The light from a Cepheid displayed a distinct pulsating pattern, which could be used as a distant indicator.

Hubble expanded on the work of astronomer Vesto Slipher, who was the first to observe the redshift of distant galaxies (although they were called spiral nebula at the time, because it was not yet known that other galaxies existed beyond our Milky Way). The redshift meant that incoming light waves were stretched, indicating that the observed light was moving away. This provided evidence that the galaxies were moving away from the earth. And even more significant, Hubble found that all galaxies were also moving away from each other.

Hubble’s observations confirmed that the universe was expanding. Upon learning the news, Einstein went back to his equations and removed the cosmological constant, as it was no longer needed to maintain the former belief of a static universe. It has been reported that Einstein called the cosmological constant his “greatest blunder.” Despite Einstein’s claim, the cosmological constant would resurface many decades later, but it came as an unexpected turn of events.

The Universe is Accelerating

galaxyAs of 1998 the expansion rate of the universe over cosmic time was still unknown. Either the universe would continue to expand forever, or the gravitational effects of galaxies would cause the expansion to slow down and perhaps stop. If at some time the expansion did stop, then it would stand to reason that gravity would cause the universe to collapse. This would lead to something like the opposite of a big bang (a big crunch).

The rate of expansion will determine the future fate of the universe. But how can one determine the expansion rates at different time periods? How can we know how the current expansion rate compares with past rates? Fortunately, the universe is extremely large and extremely old. Light from faraway galaxies can take millions and billions of years to reach the earth. This allows astronomers to go back in time and examine galaxies as they were in the past. The light we see now was emitted many years ago; these stars and galaxies appear as they once were.

Two international teams, one lead by Saul Perlmutter, the other by Brian Schmidt, set out to determine the expansion rate over cosmic time. They applied some creative methods based on a specific type of exploding star, called a Type Ia supernova. At the end of their lives these particular stars explode in a consistent pattern, which signal an intrinsic brightness. The astronomers determined a star’s distance from earth using the information from a Type Ia supernova. Then they calculated the redshift of the star’s host galaxy, and made the calculations with a number of galaxies at various times in the past.

Accelerating universeThe two teams eventually arrived at the same conclusion. The galaxies are currently receding faster than they were in the distant past; the universe is accelerating! This was an unexpected result, as it was mostly assumed that the expansion was slowing down over time (due to the attractive force of gravity).

The Return of the Cosmological Constant

If gravity is an attractive force, then what could be causing the universe to speed up. Enter the cosmological constant or its reincarnation, dark energy. Einstein’s hypothesis of a repulsive force that was counteracting gravity may not have been far off base (though his reason for introducing it was misguided). An unknown form of energy in empty space seems to be responsible for the acceleration of the universe. It has been dubbed dark energy because it does not emit light, but it could also be a term that points to the mysterious nature of this type of energy. Dark energy does, however, make up 70% of the total energy of the universe. Remarkably, this has been calculated and it seems to describe the universe we live in.

One more point of note: Since dark energy/cosmological constant is presumed to occupy all of space, its overall influence increases as space expands. Therefore in the distant past, when the universe was more condensed (relatively speaking) attractive gravity was dominant. The expansion of the universe slowed down at some point. However, as space swelled and galaxies moved farther apart, the dark energy caught up and then surpassed gravity as the dominant force. The tables turned, causing the universe to speed up.

Current evidence supports a cosmic story in which the universe will continue to expand practically forever. Galaxy clusters, like our local group, will still be held together by normal gravity, because they contain enough matter. However, in the far future all evidence from beyond our local group will disappear. The universe will be comprised of a bunch of island universes.

 

References: Mysteries of a Dark Universe: Uploaded on Oct. 31, 2011. https://www.youtube.com/watch?v=QUpWCRadIIA

Brian R. Greene, The Fabric of the Cosmos (New York: Alfred A. Knopf, 2004).


 

Decoding Light to Unlock the Secrets of the Universe

prism Much of what we know about the large-scale universe is due to decoding signals from light. The light that reaches the earth from faraway galaxies arrives as a wide spectrum, which is much more than visible light (or white light). Light is actually an electromagnetic wave with a range of wavelengths. White light is but a tiny band in the middle of the spectrum of wavelengths. When white light is refracted, such as passing through a prism, we see the colors of the rainbow.

If we move past the red band the wavelengths get longer, from infrared to microwaves to radio waves. Moving towards the opposite side of the spectrum, past the violet band, the wavelengths get shorter, from ultraviolet to x-rays to gamma rays. Even though the large majority of light is invisible to us, scientists have instruments that can detect information from the spectrum. The following list shows 5 things we know about the universe from decoding light.

1) The Contents of the Universe

Exploring the universe started simple with just visible light; ancient astronomers gazed at the night sky with the naked eye. All the twinkling yellow dots basically looked identical. They could not determine the size and distance of objects. The advent of the telescope added detail to the night sky, such as differentiating stars from planets and discovering individual galaxies.

Space telescopes, like Hubble and Kepler, are now placed in the earth’s orbit. From above the atmosphere, these and other instruments are collecting a tremendous amount of details about the universe. For example, the Hubble Space Telescope focused on a dark spot in the sky for a period of 10 days. In this tiny patch (roughly the opening of a drinking straw) an image of 10,000 galaxies was produced.

2) The Existence of Extrasolar Planets

In recent years, over 1,700 planets outside our solar system have been discovered (some of them are earth-like). Most planets orbit stars, therefore planets can be detected by examining changes in starlight, which are caused by existing planets. Astronomers use a number of methods to find planets. The two most effective methods are:

  1. The transit method: By observing a star for a period of time a planet will occasionally pass in front of the star. Viewed from earth, a planet will cause the starlight to dim slightly, thus announcing the planet’s presence.
  2. The Doppler method: As a planet orbits a star it exerts a gravitational effect on the star, which causes the star to wobble slightly. This can be detected by examining variations in the light spectrum as the star moves towards or away from the earth.

3) The Chemical Composition

Light from distant stars and galaxies can be converted into a spectrum of colors. This is achieved with an instrument called a spectroscope, which is attached to a telescope. This is perhaps the most valuable tool for decoding light. As it pertains to the chemical composition of the universe, a particular property of light contains precise information from its source.

When the light spectrum of a star is displayed by a spectroscope, vertical lines (called absorption lines) appear at specific locations, depending on the elements contained in the star. Each element produces a unique pattern of lines, which can be matched with experiments in a laboratory. Even though the information contained in the spectrum will be from a number of elements, the distinct pattern of each element can be sorted out.

Absorption lines

Absorption lines

By studying the information from light, astronomers have found that all the stars in the universe have more or less the same chemistry (including our sun). Thus, knowing that all the elements originate in stars, the chemical composition of the universe is essentially the same everywhere. The elements found here on earth are plentiful in other galaxies as well, leaving us to speculate that other life-sustaining planets may be out there.

4) The Universe is Expanding

There is another valuable piece of information from the spectroscope that has transformed our view of the universes. It is called a redshift. When the spectrum from distant galaxies is examined, the vertical lines are shifted towards the red end. This is due to the Doppler effect or the Doppler shift, and it has to do with the nature of waves. Light is a wave, and similar to sound waves, incoming waves will be stretched when the source is moving away; thus causing the absorption lines to shift towards the red end of the spectrum.

Redshift

Redshift

The conclusion from this information is that galaxies are moving away from us. The universe is expanding. The exception to this rule is that nearby galaxies are not expanding, because they are held together by gravitational forces. But for the universe as a whole, galaxies are moving away from each other. In other words, the earth’s location is not unique; the view from any location in the universe would be similar. Incidentally, it is actually the space that is expanding. The galaxies are rushing away because they are being pulled by the swelling of space.

5) The Big Bang

There are 3 ways we can get to a big bang origin of the universe by studying light:

  1. The expansion rate: The universe is expanding at a defined rate (based on the redshift), which is simply stated as: distant galaxies that are twice as far away from us are moving twice as fast, and galaxies that are 3 times as far are moving 3 times as fast. This means that if we reverse the timeline, in the distant past all the galaxies would converge at a point of infinite density. This was the moment of creation.
  2. The cosmic microwave background radiation: The CMBR is the remnant of the intense energy that was created at the big bang. The light from the big bang event has propagated throughout space, and is presently detectable as microwave radiation. Although the radiation is now faint, it is present in all directions of space.
  3. The agreement between prediction and observation: The amount of lighter elements (hydrogen, helium, deuterium and lithium) that are now present in the universe agrees with the predictions of the big bang theory. The quantity of these elements were detected from light coming from old stars and distant galaxies. The amounts are consistent with what the theory predicts would have been created in the early universe.

From an everyday perspective, light illuminates the world and we see things as a consequence. However, when we examine the large-scale universe our eyes alone are not sufficient. It is remarkable that light from very far away contains information from its source. And if not for ingenious techniques in decoding light, figuratively speaking, we would forever remain in the dark.

 

References: Richard Dawkins, The Magic of Reality

Lawrence M. Krauss, A Universe from Nothing

Stephen Hawking’s Universe -101- Seeing is Believing (June 14, 2013) https://www.youtube.com/watch?v=5kgPxvJqvEA
The Big Bang: Observational Evidence (June 4, 2012) https://www.youtube.com/watch?v=8WaI-iIlgdI


A Special Time

This blog site was inspired by our book, The Landscape of Reality (Nov. 18, 2014). The blog is an offshoot or extension from some of the themes in the book. The blog will focus on creative ideas and concepts from science, nature and philosophy. All with the intent of providing a perspective of life that is in line with the physical and natural world. The content will be tailored for a general audience. I define the three fields in the following manner:

  • Science is about a factual and logical understanding of the world and the universe. The foundation of science is verifiable evidence.
  • Nature is more closely associated to living things and how we experience the world, but not exclusively. One could also view nature as the source, and science as the field of study.
  • Philosophy is about how we think and apply the concepts, what it means for us.

 Why a Special Time?

In all of human history, no time compares to the last century in terms of change and increased knowledge. Aside from advancements in science that have eased many of life’s burdens, new and exciting discoveries are revealing the universe’s true colors. The scientific endeavor has uncovered explanations of our world and beyond, which call to question long-held beliefs. We, as individuals and as a species, have the opportunity to understand the nature of our existence in ways that past generations could not have imagined.

Galaxy Cluster

Galaxy Cluster

Lawrence M. Krauss and Bob Scherrer wrote concerning the picture of the large-scale universe:

“We live at a very special time…the only time when we can observationally verify that we live at a very special time!”

There is an intriguing implication behind this quote. According to Krauss, due to the expansion of the universe, galaxies will get increasingly farther apart. At some point in the far future, galaxies will become so isolated that all evidence of the cosmological picture of the universe will disappear. From any galaxy, potential observers will not detect anything beyond their own galaxy. They will arrive at the conclusion that the universe consists of only a single galaxy (the same view that people had before the last century), and they will be completely wrong.

 A Drastic Change of Perspective

  • Before the last century: The earth was viewed as part of a solar system, within a collection of stars (there were no known planets outside our solar system). All stars were contained within a single galaxy of a static universe.
  • After the last century: The earth is now known to be located on the outer edge of an ordinary galaxy (hundreds of planets outside our solar system have been discovered). The Milky Way is part of a huge conglomerate of billions of galaxies within an expanding universe.

 A Philosophical Angle

Before the development of modern science, natural philosophy was the term used to describe the study of nature and the physical universe. In this sense, science emerged out of philosophy. The critical difference that allowed science to branch out from philosophy was the requirement that science relied on experimentation to acquire knowledge. Still, the two have been closely linked for a long time.

In the early period of science the focus was on uncovering the laws that governed nature. The application of science came later as mankind learned they could manipulate nature for their own benefit. Now the applied sciences seem to have captured the imagination of the general population. Technologies of every kind are dominating our lives. But I caution that an opportunity to fully appreciate and understand the laws of nature is being missed. And that our excesses from modernization are growing faster than our ability to monitor the changes to our planet and ourselves.

Nevertheless, it is clear that science cannot be viewed solely as an applied field. The current scientific picture has philosophical implications as well. Learning about science can be an intellectual pursuit that has the power to enrich our lives at a philosophical and emotional level. The time is ripe for making science accessible and meaningful to the general population. Explanations from different areas of science are now merging well together, and form a view of reality that is utterly fascinating and awe-inspiring. Those are the feelings I hope to convey in the blog posts that will follow.

Ray of Sunlight

 

References: Lawrence M. Krauss, A Universe from Nothing (New York: Free Press, 2012)