Throughout man's history we have tried to make connections between the earth and the universe. Most recently mathematicians Blake Temple and Joel Smoller have made such a connection by developing a new theory that explains the mysterious forces behind our ever-faster expanding universe. What causes the universe to expand and at what rate of accelleration or decelleration? How we do we determine this and are there other forces at work, such as dark energy?
These questions are discussed in the article Mathematicians' Alternate Model of the Universe Explains Away the Need For Dark Energy by Jeremy Hsu in Popular Science and Erasing Dark Energy by Veronique Greenwood in Seed Magazine. But before we begin we must first understand some vocabulary that these article center around. As defined on Dictionary.com Dark Energy is "in physics, a hypothetical force that affects the behavior of photons, counteracts gravity, and causes the universe to expand at an ever-increasing rate." Dark Matter is defined as "a hypothetical form of matter invisible to electromagnetic radiation, postulated to account for gravitational forces observed in the universe."
Dark energy was first proposed by Einstein in 1917 and was self-labeled as his biggest blunder. Turns out Einstein was wrong. Einstein was working on his theory of General Relativity trying to come up with an equation that describes a static universe. That is one that stands still and does not collapse under the force of gravity. In order to keep the universe static in his theory, Einstein introduced a cosmological constant, dark energy, a force that opposes gravity and keeps the universe from collapsing. However in present day we are still uncertain if dark energy is a viable theory and many Cosmologists are on the fence with this topic.
Using one of Einsteins theories, General Relativity (that all motion must be defined relative to a frame of reference and that space and time are relative), Mathematicians Temple and Smoller propose that Earth sits near the center of an expanding wave beggining after the Big Bang. They believe this by itself does not represents a constant accelerating force. There are several serious issues with this proposal however.The most important is that the model requires Earth to be at the center of the universe. This violates the Copernican principle which states the Earth is not in a central position, in this case the center of the universe. Other Cosmologists are also finding much more evidence that dark energy is infact real. Could Smoller and Temple be making the same mistake made hundreds of years ago when people thought that the earth was the center of the solar system?
They disagree. Temple and Smoller believe that their theroy with respect to Einsteins equations accurately disregards the enigmatic stuff we call dark energy. Dark energy is such a phenamenom in the universe that it would have make up 70% of the universe with 20% making up dark matter and 4% belonging to matter such as planets and stardust which we live on. In the 1990's there were two teams who surveyed the light from a Type Ia supernovae. Temple and Smoller used their data and tried to explain the brightness of these huge explosions. The measurement of light found would let scientists deduce how far and how fast the universe has expanded since the light began its journey.
For reference light travels at a constant with respect to time which means that light viewed from earth millions of light years away alows us to essentially looking at images that occured millions of years prior. This is because lights' constant speed takes time to reach earth. While we look at one image from lets say 1 million years ago, the present day image of that object is just beggining its' journey. Back to the Data. What the two teams, who surveyed the supernovae, should of have found was that the universe’s expansion was slowing down due to the gravitational pull of matter. What they did observed was the opposite. The supernovae was receding at a rate that would indicate their was not gravity or any matter at all, which exerts gravity. This is where dark energy comes into the equation.
The supernovae was actualy dimming at an accelerating rate which points towards a wave of accelerating expansion. Temple and Smoller found this interesting and performed a series of studies on shockwaves. They found that expanding waves with a point of refernece near the center could account for the dimming effects. That is that earth is near center of the universe, after the big bang, i.e. general relativity, and could produce the dimming effects the two teams described.
After collaborating with other mathmaticians and astrophysicists Temple and Smoller feel that that an accelerating wave of expansion, such as that produced by the Big Bang, could push matter across the universe. This would spread galaxies farther apart the more distant they got from the wave’s center. Heres and example, imagen the center of your palm as the big bang and the tips of your finagers as galaxies. Make a fist and slowly opend your hand till your fingers are equally spread out and outstreched. This is essentially what Smoller and Temple believe is causing the dimming of light from the studied supernovaes, they were pushed far away at the beginning of the universe. What I suspect this means is that the light that was observed represents the increase in acceleration during the time of the big bang since we can only view light from the past and must infact wait an extended period of time before Earth itself can view light from right now.
This research help explains the effect that astronomers observed using only general relativity. It also complements a theory discussed in cosmology, the “bubble of underdensity”. The "bubble of underdensity" is an idea that the Earth could be in a area of low mass density compared to the rest of the universe. This could mean that we are infact close to the center of the universe or that the lack of matter has had an effect on the light viewed from the supernovae. All in all Smoller and Temple recognize that their version is not perfect and to create a testible perdiction they must further study the date to see if their theroy accurately fits the observations made. Standing against significant amount of evidence which supports dark energy it will be interesting to see which direction the data flows.
Greenwood, Veronique. "Why do we need dark energy to explain the observable universe? Two mathematicians propose an alternate solution that, while beautiful, may raise even more questions than it answers." Seed Magazine. Seed, 24 Sept. 2009. Web. 30 Sept. 2009.
http://seedmagazine.com/content/article/erasing_dark_energy/P1/
Hsu, Jeremy. "Mathematicians' Alternate Model of the Universe Explains Away the Need For Dark Energy." Popular Science. Popular Science, 25 Sept. 2009. Web. 30 Sept. 2009.
http://www.popsci.com/military-aviation-amp-space/article/2009-09/mathematicians-seek-explain-away-dark-energy-universe?page=
These questions are discussed in the article Mathematicians' Alternate Model of the Universe Explains Away the Need For Dark Energy by Jeremy Hsu in Popular Science and Erasing Dark Energy by Veronique Greenwood in Seed Magazine. But before we begin we must first understand some vocabulary that these article center around. As defined on Dictionary.com Dark Energy is "in physics, a hypothetical force that affects the behavior of photons, counteracts gravity, and causes the universe to expand at an ever-increasing rate." Dark Matter is defined as "a hypothetical form of matter invisible to electromagnetic radiation, postulated to account for gravitational forces observed in the universe."
Dark energy was first proposed by Einstein in 1917 and was self-labeled as his biggest blunder. Turns out Einstein was wrong. Einstein was working on his theory of General Relativity trying to come up with an equation that describes a static universe. That is one that stands still and does not collapse under the force of gravity. In order to keep the universe static in his theory, Einstein introduced a cosmological constant, dark energy, a force that opposes gravity and keeps the universe from collapsing. However in present day we are still uncertain if dark energy is a viable theory and many Cosmologists are on the fence with this topic.
Using one of Einsteins theories, General Relativity (that all motion must be defined relative to a frame of reference and that space and time are relative), Mathematicians Temple and Smoller propose that Earth sits near the center of an expanding wave beggining after the Big Bang. They believe this by itself does not represents a constant accelerating force. There are several serious issues with this proposal however.The most important is that the model requires Earth to be at the center of the universe. This violates the Copernican principle which states the Earth is not in a central position, in this case the center of the universe. Other Cosmologists are also finding much more evidence that dark energy is infact real. Could Smoller and Temple be making the same mistake made hundreds of years ago when people thought that the earth was the center of the solar system?
They disagree. Temple and Smoller believe that their theroy with respect to Einsteins equations accurately disregards the enigmatic stuff we call dark energy. Dark energy is such a phenamenom in the universe that it would have make up 70% of the universe with 20% making up dark matter and 4% belonging to matter such as planets and stardust which we live on. In the 1990's there were two teams who surveyed the light from a Type Ia supernovae. Temple and Smoller used their data and tried to explain the brightness of these huge explosions. The measurement of light found would let scientists deduce how far and how fast the universe has expanded since the light began its journey.
For reference light travels at a constant with respect to time which means that light viewed from earth millions of light years away alows us to essentially looking at images that occured millions of years prior. This is because lights' constant speed takes time to reach earth. While we look at one image from lets say 1 million years ago, the present day image of that object is just beggining its' journey. Back to the Data. What the two teams, who surveyed the supernovae, should of have found was that the universe’s expansion was slowing down due to the gravitational pull of matter. What they did observed was the opposite. The supernovae was receding at a rate that would indicate their was not gravity or any matter at all, which exerts gravity. This is where dark energy comes into the equation.
The supernovae was actualy dimming at an accelerating rate which points towards a wave of accelerating expansion. Temple and Smoller found this interesting and performed a series of studies on shockwaves. They found that expanding waves with a point of refernece near the center could account for the dimming effects. That is that earth is near center of the universe, after the big bang, i.e. general relativity, and could produce the dimming effects the two teams described.
After collaborating with other mathmaticians and astrophysicists Temple and Smoller feel that that an accelerating wave of expansion, such as that produced by the Big Bang, could push matter across the universe. This would spread galaxies farther apart the more distant they got from the wave’s center. Heres and example, imagen the center of your palm as the big bang and the tips of your finagers as galaxies. Make a fist and slowly opend your hand till your fingers are equally spread out and outstreched. This is essentially what Smoller and Temple believe is causing the dimming of light from the studied supernovaes, they were pushed far away at the beginning of the universe. What I suspect this means is that the light that was observed represents the increase in acceleration during the time of the big bang since we can only view light from the past and must infact wait an extended period of time before Earth itself can view light from right now.
This research help explains the effect that astronomers observed using only general relativity. It also complements a theory discussed in cosmology, the “bubble of underdensity”. The "bubble of underdensity" is an idea that the Earth could be in a area of low mass density compared to the rest of the universe. This could mean that we are infact close to the center of the universe or that the lack of matter has had an effect on the light viewed from the supernovae. All in all Smoller and Temple recognize that their version is not perfect and to create a testible perdiction they must further study the date to see if their theroy accurately fits the observations made. Standing against significant amount of evidence which supports dark energy it will be interesting to see which direction the data flows.
Greenwood, Veronique. "Why do we need dark energy to explain the observable universe? Two mathematicians propose an alternate solution that, while beautiful, may raise even more questions than it answers." Seed Magazine. Seed, 24 Sept. 2009. Web. 30 Sept. 2009.
http://seedmagazine.com/content/article/erasing_dark_energy/P1/
Hsu, Jeremy. "Mathematicians' Alternate Model of the Universe Explains Away the Need For Dark Energy." Popular Science. Popular Science, 25 Sept. 2009. Web. 30 Sept. 2009.
http://www.popsci.com/military-aviation-amp-space/article/2009-09/mathematicians-seek-explain-away-dark-energy-universe?page=
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