Kenny A. Chaffin
All Rights Reserved © 2013 Kenny A. Chaffin
Hello darkness my old friend
I’ve come to talk with you again
- Sounds of Silence
by Paul Simon
There is no dark side of the moon really.
There is no dark side of the moon really.
Matter of fact it's all dark.
- Eclipse (Dark side of the Moon)
Dark matter, dark energy, the dark side of the Moon…..hmmmm….I think we better talk. A couple of decades ago everything was cool. We knew the universe was expanding and the thought was that it would either continue expanding or reverse course and begin collapsing due to gravity. In either case it was assumed that the rate of the expansion would slow due to gravity. We’d never seen any slowing so have been looking to verify this claim. Then along comes the damn Hubble Space Telescope screwing everything up! Its observations of distant galaxies in 1998 showed just the opposite. Not only was the expansion not slowing but the rate of expansion was increasing! It was as if some force were pushing the galaxies apart every faster. There was no explanation that fit. Enter confusion and a new hypothesis – Dark Energy -- thrown in to the cosmological mix to explain the accelerating rate of expansion. Now if you’re getting a feeling of déjà vu, blame it on Einstein and his cosmological constant. He claimed it was his biggest mistake – adding it into his general relativity equations and then removing it. It has again been resurrected as an explanation for the accelerating expansion of the universe we now see. Or perhaps this begins to sound more like Roger Water’s Dark Side of the Moon lunatic or maybe Roger Penrose’s quantum mind. It’s all dark, really.
Dark energy is the name cosmologists have assigned to this unexplainable observation, somewhat in relation to the ‘vacuum’ energy of space. This is not science, this is speculation. We don’t know what is going on really we only have observations awaiting an explanation. Dark energy is a hypothesis, not a theory as there is no way to verify it because on its definition. It only interacts with normal matter in the form of gravity. There is no way to observer it, measure it, or test it beyond the indirect observations of galactic expansion. And how is that different than some unknown feature, force or characteristic of the universe that we simply do not understand at this point? The problem as I see it is that this ‘theory’ of dark energy has been feed to the public in sensational news headlines and popular science articles as if it were real science. This is misleading at best and deceptive at worst in my opinion since it makes it sound like there is a clearly identified cause – dark energy. That is what the public takes from these twitter-like headlines, particularly since most readers don’t get beyond those headlines. The truth is that we don’t know if any such thing as dark energy exists, we have an unexplained observation and that is all we know. Would it not be better to simply say, “Yes the rate of expansion of the universe appears to be increasing but we do not know why?” Unfortunately science is acting more like a religion and claiming that it has answers to the unknown when in fact it does not. In this age of the media and marketing as kingmaker science communicators can fall into the same trap of sensationalizing their stories. But enough of that just call me a lunatic if you like.
Something is responsible for the accelerating rate of expansion of the universe. Something we don’t understand, perhaps there is a cosmological constant that we’ve yet to identify and understand, perhaps there is a problem with Einstein’s General Relativity Equations, perhaps there really is some form of energy here-to-fore unidentified that is pushing the galaxies apart faster and faster. Or perhaps there is some error or issue with our deep-space, deep-time observations.
As you can see in the above illustration, measurements show that the direction of the curve changes about 7.5 billion years ago. What might have happened at that point in the universe? Could it be that the ‘vacuum energy’ of space changed at that point due to physical expansion? This is unknown of course. As new space came into being did additional dark energy appear as well? The belief at this point is that 68% of the universe is actually dark energy with another 27% is dark matter. Now it is certainly something of a dark matter that leaves only 5% of the universe as normal matter. That 5% is everything we know, you, me, all the planets, stars, asteroids and hydrogen clouds, everything we previously assumed was the entire constitution of the universe. With the emergence of dark matter and dark energy everything we thought we knew has been turned upside down as though we were in an Alice in Wonderland story.
Before we go too far, let’s look back at dark matter. It was first proposed by Jan Oort (of Oort cloud fame) in 1932 to account for the orbital velocities of stars in the Milky Way. Others have shown additional situations that require dark matter in order to explain gravitational anomalies. Dark matter doesn’t seem to be as unbelievable as dark energy as it is thought to be ordinary matter which is not easily detectable either optically or by other observational methods. The effect is primarily seen through gravity on orbits, velocities and movement of stars and galaxies. It seems very possible there are massive amounts of normal matter strewn throughout the universe collectively known as massive compact halo objects or MACHOs that could be enough to cause gravitational anomalies but we have not been able to detect enough possible candidates to conclude that this is the case. Another possibility is nonbaryonic dark matter (such as WIMPS – weakly interacting massive particles) which would not be detectible by electromagnetic means. This appears to be the leading candidate for the source of dark matter. While most cosmologists agree that dark matter exists and explains the anomalies there are alternative hypotheses/theories of gravity that attempt to explain the discrepancies without resorting to unobservable matter.
This three-dimensional map offers a first look at the web-like large-scale distribution of dark matter, an invisible form of matter that accounts for most of the Universe's mass. The map reveals a loose network of dark matter filaments, gradually collapsing under the relentless pull of gravity, and growing clumpier over time. The three axes of the box correspond to sky position (in right ascension and declination), and distance from the Earth increasing from left to right (as measured by cosmological redshift). Note how the clumping of the dark matter becomes more pronounced, moving right to left across the volume map, from the early Universe to the more recent Universe. (Credit: NASA/ESA/Richard Massey (California Institute of Technology))
So the effect of dark energy we observe is somewhat the opposite of the effect of dark matter. Dark matter has a gravitational pull and effect on stars, planets, galaxies and all normal matter in the same way they affect and attract one another. Dark energy on the other hand creates a constant ‘anti-gravity’ force that pushes everything apart and accelerates the on-going expansion of space. The following illustration from NASA shows the change in composition from the origin of the universe 13.7 billion years ago to what we see today. Note the increasing percentage of dark energy. This sort of makes sense as there was only a certain amount of matter in the original universe and as it expands what is added is space and along with it the vacuum energy which seems to include increasing amounts of dark energy.
So we have a mystery. It’s a scientific mystery not unlike others that we encounter at the edges of science, in this case the science of cosmology. Dark energy is proposed as a hypothesis to explain the accelerating expansion of the universe though we have no means of measuring, detecting or verifying that that is the case. Dark energy is really just a placeholder for something we don’t understand. It seems to harken back even beyond Einstein’s cosmological constant to the ether theory that was proposed before Maxwell provided us with an understanding of electromagnetic waves. For the non-scientist reading about this research in the media it can be confusing and the casual reader will come away thinking dark energy is a real thing because science said so. Most readers don’t think too deeply about it and figure it’s something like atoms or quarks or photons when in fact it is nothing of the sort. It is nothing more than a hypothesis, and perhaps not even that because to be a true hypothesis it must be testable and from what has been proposed there is no way to test, verify, or validate dark energy. There is only the observation which it is hypothesized to explain – a circular definition in other words. This is the dark side and dark matters.
It is incumbent upon all scientists and science communicators to be as up-front, open and honest as possible with the public. There is a distrust of science that has been building since the mid-20th century. We must take care to not exacerbate the situation in these times of global warming and genetic engineering, these times of political and religious attacks on science. We must work with the public to build bridges of trust and support by stepping out of the darkness and conveying scientific knowledge in the light of truth and full disclosure and thereby regain public trust and support.
The Sounds of Silence:
Expansion of Universe Illustration:
Distribution map of Dark Matter:
WMAP Content of the Universe graph:
About the Author
Kenny A. Chaffin writes poetry, fiction and nonfiction and has published poems and fiction in Vision Magazine, The Bay Review, Caney River Reader, WritersHood, Star*Line, MiPo, Melange and Ad Astra and has published nonfiction in The Writer, The Electron, Writers Journal and Today’s Family. He grew up in southern Oklahoma and now lives in Denver, CO where he works hard to make enough of a living to support two cats, numerous wild birds and a bevy of squirrels. His poetry collections No Longer Dressed in Black, The Poet of Utah Park, The Joy of Science, A Fleeting Existence, a collection of science essays How do we Know, and a memoir of growing up on an Oklahoma farm - Growing Up Stories are all available at Amazon.com: http://www.amazon.com/-/e/B007S3SMY8. He may be contacted through his website at http://www.kacweb.com.