Showing posts with label Cosmology. Show all posts
Showing posts with label Cosmology. Show all posts
Sunday, November 30, 2014
Friday, November 14, 2014
Unity of Existence
Shaykh al-Akbar Imam ibn Arabi al-Hatimi at-Tai termed this concept "the Unity of Existence" — al-Wahdat al-Wujud.
A common argument against the concept of al-Wahdat al-Wajud, often brought up by the Wahhabi Muslims such as the likes of Dr. Zakir Naik and Dr. Bilal Philips, is that it is Shirk in the form of Pantheism: untrue.
Pantheism is the belief that God is present in creation in the physical sense which is, thus, worshiped. This leads to paganism and idolatry as the objects in creation are directly worshiped as God, reducing Them to being bound in three-dimensional entities existing within spacetime.
In sharp contrast, Wahdatul-Wujud enhances God beyond any space, time or dimensional boundaries by stating that if everything in being was extended to infinity, nothing would remain but God. That is, a two-dimensional picture of
a house can be rendered into three-dimensional form, converting the image into an actual house with height, weight, width and length. However, if everything in existence was, similarly, rendered into infinite dimensions, then it would all cease to exist except for God. Therefore, in the greater scheme of things, we conclude, nothing exists but God.
a house can be rendered into three-dimensional form, converting the image into an actual house with height, weight, width and length. However, if everything in existence was, similarly, rendered into infinite dimensions, then it would all cease to exist except for God. Therefore, in the greater scheme of things, we conclude, nothing exists but God.
This is the Ultimate Truth. This is the Unity of Creation and All of Existence. This is Wahdat al-Wujud.
Wednesday, October 29, 2014
Metaphysics Of God
The universe is finite. Beginning from a single point in time as a constricted singularity of particles, dense and hot, and then expanding faster than the speed of light at the trillionth of a second following the Big Bang approximately 13.8 billion years ago, the universe is headed towards an end.
Stars turn into black holes, planets degrade and die, the fabric of the cosmos is ever being stretched apart by the accumulation of dark matter, and the expansion rate, after decelerating around 10.8 billion years ago due to the attractive gravitational pull of matter holding the myriad galaxies and solar systems together, has now begun to accelerate due to the repulsive gravitational push of dark energy.
Given the current knowledge of the expansion of the universe, it is an inevitable conclusion that the universe most certainly will end. As the universe expands ever faster, all of gravity's work will be undone. Clusters of galaxies will disband and separate. Then galaxies themselves will be torn apart. The solar system, stars, planets, and even molecules, quarks and atoms will be shredded down by the resultant consequences of the great cosmic phenomenon. The universe that was born in the Big Bang would end with the Big Rip: the end of all space and time and matter.
The ancient model of the endless, infinite universe has thus been proven to be false. A conceptual potential infinite aside, there can never quite be an actual infinite from a mathematical standpoint existing in the real world because the existence of an infinite number of anything leads to logical contradictions.
If the universe did not have a beginning, then the past would be infinite, that is, there would be an infinite number of past times. There cannot, however, be an infinite number of anything, and so the past cannot be infinite, and so the universe must have had a beginning, which we know as the phenomenon of the Big Bang.
Question: why do we say that an actual infinite is not realistically possible when concepts of a potential infinite exist? Proposition: Hilbert's Hotel. Hilbert’s Hotel is a hypothetical hotel with an infinite number of rooms, each of which is occupied by a guest. As there are an infinite number of rooms and an infinite number of guests, every room is occupied; the hotel cannot accommodate another guest. However, if a new guest arrives, then it is possible to free up a room for them by moving the guest in room no. 1 to room no. 2, and the guest in room no. 2 to room no. 3, so on. As for every room 'n' there is a room 'n + 1,' therefore, every guest can be moved into a different room, thus leaving room no. 1 vacant. The new guest can, then, be accommodated after all. This is clearly paradoxical; it is not possible that a hotel both can and cannot accommodate a new guest. Hilbert’s Hotel, therefore, is not possible.
Question: What if the scenario was applied to the concept of the past? Can we realistically have an infinite past? Answer: If there exists an infinite past and we were to assign a number to each moment in time of the past then every positive integer would be assigned to some moment. There would therefore be no unassigned number to be assigned to the present moment as it passes into the past. However, by reassigning the numbers and shifting them as such that moment no. 1 becomes moment no. 2, and moment no. 2 becomes moment no. 3, so on and so forth, we could free up moment number one to be assigned to the present. If the past is infinite, therefore, then there both is and is not a free number to be assigned to the present as it passes into the past.
That such a paradox results from the assumption that the past is infinite, it is claimed, demonstrates that it is not possible that that assumption is correct. The past, it seems, cannot be infinite, because it is not possible that there be an infinite number of past moments. If the past cannot be infinite, then the universe must have had a beginning. Once again, this we know as the Big Bang.
The past has been created by successive addition. The past continuously grows as one moment after another passes from the future into the present and then into the past. Every moment that is now past was once in the future, but was added to the past by the passage of time.
If actual infinites cannot be created by successive addition, and the past was created by successive addition, then the past cannot be an actual infinite. The past must be finite, and the universe must therefore have had a beginning.
Finally, we have the concept that actual infinites cannot be traversed.
If I were to set out on a journey to an infinitely distant point in space, it would not just take me a long time to get there; rather, I would never get there. No matter how long I had been walking for, a part of the journey would still remain. I would never arrive at my destination. Infinite space cannot be traversed.
Similarly, if I were to start counting to infinity, it would not just take me a long time to get there; rather, I would never get there. No matter how long I had been counting for, I would still only have counted to a finite number. It is impossible to traverse the infinite set of numbers between zero and infinity.
This also applies to the past. If the past were infinite, then it would not just take a long time to the present to arrive; rather, the present would never arrive. No matter how much time had passed, we would still be working through the infinite past. It is impossible to traverse an infinite period of time.
Clearly, though, the present has arrived, the past has been traversed.
Clearly, though, the present has arrived, the past has been traversed.
The past, therefore, cannot be infinite, but must rather be finite.
The universe has a beginning.
The evident conclusion, therefore, is this: the universe, that is, all of space, matter and time, the past, the present and the future, everything, had a beginning. Mathematically and physically speaking, the universe is finite. And this does not only hold true for our universe but for any number of universes besides this one wherein we exist that all of them is finite and not endless. Thus, even the multiverse hypothesis fails to escape the result of this conclusion.
If all of space-time started from a united compact singularity of particles, smaller than an atom, even that could not have existed forever because its very constituents are finite and finite constituents cannot compose an infinite entity. Therefore, nothing within our immediate universe is truly infinite.
And since this very particle expanding to formulate the current universe itself is finite, it must have had a beginning and there must have been something to cause it to begin. This primal cause for the beginning of every particle must, on the other hand, be infinite and eternal or else it would, too, need a cause for its own existence and that would initiate a sequence of infinite regress. There has to be something at the very beginning of everything, therefore, that transcends the need for a cause and thus be eternal. The primal cause, hence, must be an entity of infinite actuality.
Also, as consequence of what we have established earlier, this entity has to exist outside our universe and outside the boundaries of time and space as we experience it within this realm because, as the three propositions prove above, an actual infinity within the boundaries of our time and space is impossible. Time itself is built on event progression, each moment chained to another constructing a train of events moving forward towards an end. Like the numbers of the addition or the sands of the heap, these events are finite and the sum total of the events, too, are finite.
Space, also, is constituted of particles which are finite with a beginning and an end. Overall, the entirety of our universe is limited and cannot allow for an actual infinity to exist within its bounds. Therefore, for an entity of pure infinity to exist, one that is eternal with endless power and capability, the entity must exist outside the boundaries of time and space to be limitless and unbound. And thus, this entity is quite evidently transcendent beyond physicality.
This entity in proposition is God. And the premises presented above explain His Attributes in the sense that He is Infinite, He is Omnipotent and He is Eternal. He is Transcendent, beyond the boundaries of time and space and thus He has no physical body because in order to have a body, even if it was not like that of His creation, a physical body would still need to be constituted of substance meaning God would thus occupy space since all substance, composed of matter, regardless of properties, occupies space, thus limiting God to the existence of space, meaning He could not exist before the creation of space nor the matter that constructs the frame of His body which consequently also means that God would require the creation of this matter first for existence thus obstructing His Eternal Nature.
And since we have already discussed that anything within the physical reality of our universe cannot truly be infinite, this would mean that God is not an actual infinite and His capabilities are, therefore, not limitless and unbound, His existence and nature, thus, not eternal. This would severely compromise the ontological property of God and reduce Him from the primal cause into an entity caused as well as the rest of His creation which does not quite solve the problem of the genesis of the cosmos nor explain the existence of God but rather create another issue all by itself.
In other words, a physical, literal body would mean, by definition of the word "physical," a body that is bound by the laws of physics, a body that is corporeal and, therefore, limited. Anthropomorphic theologians may try to avert this possibility by claiming God to have a body unlike that of His creation but that really does not solve anything because a deer possesses a body unlike that of a gazelle and a gazelle possesses a body unlike that of a blackbuck but, speaking in general terms, having a body unlike that of another does not mean the body is not a body. A literal body is still corporeal regardless of its likeness to another body of another species or person and a corporeal body is, by definition, composed of substance and matter. Therefore, a literal body is bound by space-time. This is problematic.
A god who is bound by the space-time fabric cannot be the creator of space and time; such a scenario would be as asinine and ludicrous as a daughter giving birth to her own mother, and would be no less preposterous as the universe basically creating itself and coming into existence. We cannot attribute such a phenomenon to God and claim it to be the rationale for His Existence. This is the fundamental flaw of a creed of an anthropomorphic, physical deity.
The God of the primal cause, therefore, cannot be a deity with a literal body. He must be transcendent. And He must also be beyond any attribution of direction, that is, He cannot exist anywhere above or below, in the right or the left, the north or the south, east or west of His creation. Directions exist in reference to the plane of space, that is, they are spatial constructs, as are length, height and weight.
There would be no weight if there were no object bearing mass and there would be no height, breadth or length if there were no object possessing dimensions to be measured using arbitrary units for the calibration of these sorts of dimensions comprehensible by the human mind. Similarly, direction is also a mechanical construct to pinpoint spatial location for guidance and homing. Without space, there would be no direction, and beyond space, there would be no such concept either. Since God exists beyond and before the creation of space, He cannot be attributed any direction.
Stating that God is physically above us would mean that He exists in a plane above ourselves meaning that He exists within a spatial construct of His Own leading to the problem, once again, of limiting God to the fabric of space-time. Where was He, then, before this fabric of space was created? Is this spatial plane eternal and infinite? How is it so?
If this space existed eternally with God then no-one created it meaning God is not the Creator of this space.
This space, therefore, is beyond His Dominion limiting, then, His Sovereignty.
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We cannot have a God stated to be the Creator of the space-time fabric existing within spatial-time constructs. Therefore, we cannot say God exists literally above us in the spatial fabric similarly as we cannot say that God came to exist in the year 4,000,000 BC. These are measurements to calibrate space and time which did not exist before the creation of space and time, therefore, they do not apply to an entity existing infinitely before time and space.
It is for this very reason that we cannot say God literally descends from His Abode at a certain time of the day or night, that would mean that, for example, God exists 3,000 feet above Earth at 12 midnight and then later climbs down to an altitude of 1,000 feet above Earth at 3 am late-night. This means God is existing within time, His position in relation to Earth changing as the hours on the clock tick away. Such an entity, bound by spatial directional relatives and time cannot be infinite nor eternal, and it is, therefore, utter blasphemy to state such claims to be literal.
This also goes in relation to any of His Acts and Attributes in the sense that saying God is now Merciful or Forgiving while He was not so last year, etc. is equally blasphemous because that is evidently saying God changes in relation to time meaning He was of a certain nature at one point in time and then another nature in the next. God does not change relative to time. He exists beyond time. This explains the Eternal Nature of His Speech too.
God does not speak of an event as it unfolds. For example, if we take the biblical narrative of Moses being told to Muhammad in the Quran, the narrative is not being recorded by God as Moses goes through his life and actions meaning that God did not wait for Moses to arrive at Mount Sinai to speak to him through the Burning Bush and then record the narrative to then narrate it to Muhammad two-thousand years later. Once again, this would mean God exists within time and space. He does not. All those events have eternally happened from the viewpoint of God.
A good way to explain this with an example would be that of a time traveler, D, arriving at a museum around 10 AM in the morning. A security guard in the museum, B, receives a phone call from the same time traveler in the future asking him to move a painting from that museum to another location elsewhere. This evidently has not happened yet in the time traveler's own timeline when he first meets the security guard. It is after traveler D enters the museum, goes through a certain series of events within the next few hours and gets trapped in a predicament around 12 noon forcing him to call the security guard, B, in the past, at 10 AM, in B's timeline that the event happens in D's timeline. However, from the viewpoint of B, that event has already unfolded two hours ago. Time is subjectively relative.
Similarly, let us say God has already spoken to Moses at Mount Sinai and narrated the tale to Muhammad before either of the two were even born. They have yet to experience it happening in their own timeline but it has already happened in the grand picture of eternity. It is their temporal states which forces them to live through their lives until the point of that event happening in their own respective timelines. Such is the Eternal Nature of God's Speech.
In other words, everything that has happened and is ever going to happen, God has already witnessed. He is in the past, present and future all at once which is why He is aware of all our actions and deeds, what will unfold now, tomorrow and in the End of Days, these are events we have initiated to pass by our own free will but God allowed it.
He has seen everything that will happen and He has thus informed of it to His Prophets and Messengers who relayed the Message to us. These matters that we have been foretold of are not to be blamed upon God as they are of our own doing. God has simply willed our desires to happen manifest, witnessed it and warned us of it so that we know.
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Since we have established the existence of God via exposition of the primal cause, it should do well to explain why certain trends within human culture to commune with God seem to overlap with one another. If this God is Eternal and He is Conscious then He must have caused the universe to be created for a reason and He must have conveyed that reason unto His creations throughout history. We must therefore experience that communication in our own timelines as we journey through our lives and understand the nature of reality better moving forward.
Thus, it would be quite natural to see similarities in the practices and beliefs of many faiths throughout the globe as faith and religion are the routes utilized to commune with God, therefore, when God communes with Man, the same methods of communication arise repetitively, though, in time, they are corrupted and changed but the skeletal remnants are left behind as relics and bridges between the belief systems of the many tribes and nations.
This is why there are so many similarities between beliefs and theologies throughout history and culture such as the obvious existence of an Almighty Creator God, an antithetical adversary in the form of the Devil or Angra Mainyu, Prophets and Avatars, the story of Noah and Manu, an End Times messianic figure, Judgement Day, Heaven/Hell, the Bridge or the Sirat to the Final Destination of the Soul, concept of Spirits and Afterlife, ritualistic prayer services throughout the day as seen in Zoroastrianism, Judaism and Islam, a Day of Divine Remembrance in the form of the Judaic Sabbath and Islamic Jummah, among many other examples of overlaps between religions existing globally across time. These are the ties that bind us together as humanity. These are the Echoes of God.
The very reason we cannot have a corporeal primal cause is also the reason that we cannot have multiple gods or elemental ones tied to natural phenomena and abstract mortal concepts such as death. This is because for there to be an eternal god of water the existence of the element water would have to be eternal and, similarly, for there to be an eternal god of fire the existence of the element fire would have to be eternal. We know neither is eternal.
Akin to that, the concept of death would also be non-existent in a world without anything to die so death could not have existed without life and thus the concept of death is also not eternal but an aftermath of the creation of life. Therefore, there can be no eternal god of death. These can, obviously, be extrapolated for any other polytheistic conceptual or elemental god. Without their reigning concepts or elements, they would simply be gods of nothing.
A pantheistic god also poses the same dilemma in the sense that a pantheistic god is basically everything in creation meaning that the pantheistic god came into being when creation came about and not before it. Thus, the universe itself is god and the universe, therefore, created itself and then, when the universe ends, god shall end, as it came to exist when the universe came to exist. Such a god is, by definition, limited and reliant upon the finite nature of the universe and not an eternal primal cause of it, as proposed by the cosmological argument, and has no need to exist.
An Eternal God, therefore, would simply have to be, He has to exist simply because to exist is His basal nature. He is not the god of something but rather something, anything, any concept or any element, is that which He creates by nature of His Creative Act, which, is immeasurable because anything being created from infinity is not measurable from the point of infinity to its creation. This means, we can say that the universe was created 13.8 billion years ago from today but we cannot say it was created, for example, 15 billion years after infinity. Time cannot be measured from an infinite. Time is a finite concept. Finite concepts cannot be measured from an infinite starting point.
In order to explain the aforementioned statements, let us say that I started a journey from infinity to get to a given point C. I cannot say I have a walked from infinity to point C. If my initial destination is an infinite distance away from point C, I would never get to point C since the distance is infinite and shall never end. Similarly, if the universe was created 15 billion years after infinity then that would mean the span of time between the beginning of the creation of the universe and the moment before it is infinite and thus impossible to traverse. This mathematical conundrum has already been discussed far above. Infinity cannot be traversed and arbitrated using a finite set of numbers.
This is why we cannot say when God started to create the universe. We can say it came to be 13.8 billion years ago. "When" is not a concept that can be used to describe God nor His Actions and Attributes, Similarly, "where" is also not a concept that can be used to describe God and His Actions and Attributes. God only and simply exists without a "when" or a "where" for He is Infinitely Eternal. He is Omnipotent. He is Immanent. He is Almighty. He is Forever.
— Promi
The God of the primal cause, therefore, cannot be a deity with a literal body. He must be transcendent. And He must also be beyond any attribution of direction, that is, He cannot exist anywhere above or below, in the right or the left, the north or the south, east or west of His creation. Directions exist in reference to the plane of space, that is, they are spatial constructs, as are length, height and weight.
There would be no weight if there were no object bearing mass and there would be no height, breadth or length if there were no object possessing dimensions to be measured using arbitrary units for the calibration of these sorts of dimensions comprehensible by the human mind. Similarly, direction is also a mechanical construct to pinpoint spatial location for guidance and homing. Without space, there would be no direction, and beyond space, there would be no such concept either. Since God exists beyond and before the creation of space, He cannot be attributed any direction.
Stating that God is physically above us would mean that He exists in a plane above ourselves meaning that He exists within a spatial construct of His Own leading to the problem, once again, of limiting God to the fabric of space-time. Where was He, then, before this fabric of space was created? Is this spatial plane eternal and infinite? How is it so?
If this space existed eternally with God then no-one created it meaning God is not the Creator of this space.
This space, therefore, is beyond His Dominion limiting, then, His Sovereignty.
We cannot have a God stated to be the Creator of the space-time fabric existing within spatial-time constructs. Therefore, we cannot say God exists literally above us in the spatial fabric similarly as we cannot say that God came to exist in the year 4,000,000 BC. These are measurements to calibrate space and time which did not exist before the creation of space and time, therefore, they do not apply to an entity existing infinitely before time and space.
It is for this very reason that we cannot say God literally descends from His Abode at a certain time of the day or night, that would mean that, for example, God exists 3,000 feet above Earth at 12 midnight and then later climbs down to an altitude of 1,000 feet above Earth at 3 am late-night. This means God is existing within time, His position in relation to Earth changing as the hours on the clock tick away. Such an entity, bound by spatial directional relatives and time cannot be infinite nor eternal, and it is, therefore, utter blasphemy to state such claims to be literal.
This also goes in relation to any of His Acts and Attributes in the sense that saying God is now Merciful or Forgiving while He was not so last year, etc. is equally blasphemous because that is evidently saying God changes in relation to time meaning He was of a certain nature at one point in time and then another nature in the next. God does not change relative to time. He exists beyond time. This explains the Eternal Nature of His Speech too.
God does not speak of an event as it unfolds. For example, if we take the biblical narrative of Moses being told to Muhammad in the Quran, the narrative is not being recorded by God as Moses goes through his life and actions meaning that God did not wait for Moses to arrive at Mount Sinai to speak to him through the Burning Bush and then record the narrative to then narrate it to Muhammad two-thousand years later. Once again, this would mean God exists within time and space. He does not. All those events have eternally happened from the viewpoint of God.
A good way to explain this with an example would be that of a time traveler, D, arriving at a museum around 10 AM in the morning. A security guard in the museum, B, receives a phone call from the same time traveler in the future asking him to move a painting from that museum to another location elsewhere. This evidently has not happened yet in the time traveler's own timeline when he first meets the security guard. It is after traveler D enters the museum, goes through a certain series of events within the next few hours and gets trapped in a predicament around 12 noon forcing him to call the security guard, B, in the past, at 10 AM, in B's timeline that the event happens in D's timeline. However, from the viewpoint of B, that event has already unfolded two hours ago. Time is subjectively relative.
Similarly, let us say God has already spoken to Moses at Mount Sinai and narrated the tale to Muhammad before either of the two were even born. They have yet to experience it happening in their own timeline but it has already happened in the grand picture of eternity. It is their temporal states which forces them to live through their lives until the point of that event happening in their own respective timelines. Such is the Eternal Nature of God's Speech.
In other words, everything that has happened and is ever going to happen, God has already witnessed. He is in the past, present and future all at once which is why He is aware of all our actions and deeds, what will unfold now, tomorrow and in the End of Days, these are events we have initiated to pass by our own free will but God allowed it.
He has seen everything that will happen and He has thus informed of it to His Prophets and Messengers who relayed the Message to us. These matters that we have been foretold of are not to be blamed upon God as they are of our own doing. God has simply willed our desires to happen manifest, witnessed it and warned us of it so that we know.
Since we have established the existence of God via exposition of the primal cause, it should do well to explain why certain trends within human culture to commune with God seem to overlap with one another. If this God is Eternal and He is Conscious then He must have caused the universe to be created for a reason and He must have conveyed that reason unto His creations throughout history. We must therefore experience that communication in our own timelines as we journey through our lives and understand the nature of reality better moving forward.
Thus, it would be quite natural to see similarities in the practices and beliefs of many faiths throughout the globe as faith and religion are the routes utilized to commune with God, therefore, when God communes with Man, the same methods of communication arise repetitively, though, in time, they are corrupted and changed but the skeletal remnants are left behind as relics and bridges between the belief systems of the many tribes and nations.
This is why there are so many similarities between beliefs and theologies throughout history and culture such as the obvious existence of an Almighty Creator God, an antithetical adversary in the form of the Devil or Angra Mainyu, Prophets and Avatars, the story of Noah and Manu, an End Times messianic figure, Judgement Day, Heaven/Hell, the Bridge or the Sirat to the Final Destination of the Soul, concept of Spirits and Afterlife, ritualistic prayer services throughout the day as seen in Zoroastrianism, Judaism and Islam, a Day of Divine Remembrance in the form of the Judaic Sabbath and Islamic Jummah, among many other examples of overlaps between religions existing globally across time. These are the ties that bind us together as humanity. These are the Echoes of God.
The very reason we cannot have a corporeal primal cause is also the reason that we cannot have multiple gods or elemental ones tied to natural phenomena and abstract mortal concepts such as death. This is because for there to be an eternal god of water the existence of the element water would have to be eternal and, similarly, for there to be an eternal god of fire the existence of the element fire would have to be eternal. We know neither is eternal.
Akin to that, the concept of death would also be non-existent in a world without anything to die so death could not have existed without life and thus the concept of death is also not eternal but an aftermath of the creation of life. Therefore, there can be no eternal god of death. These can, obviously, be extrapolated for any other polytheistic conceptual or elemental god. Without their reigning concepts or elements, they would simply be gods of nothing.
A pantheistic god also poses the same dilemma in the sense that a pantheistic god is basically everything in creation meaning that the pantheistic god came into being when creation came about and not before it. Thus, the universe itself is god and the universe, therefore, created itself and then, when the universe ends, god shall end, as it came to exist when the universe came to exist. Such a god is, by definition, limited and reliant upon the finite nature of the universe and not an eternal primal cause of it, as proposed by the cosmological argument, and has no need to exist.
An Eternal God, therefore, would simply have to be, He has to exist simply because to exist is His basal nature. He is not the god of something but rather something, anything, any concept or any element, is that which He creates by nature of His Creative Act, which, is immeasurable because anything being created from infinity is not measurable from the point of infinity to its creation. This means, we can say that the universe was created 13.8 billion years ago from today but we cannot say it was created, for example, 15 billion years after infinity. Time cannot be measured from an infinite. Time is a finite concept. Finite concepts cannot be measured from an infinite starting point.
In order to explain the aforementioned statements, let us say that I started a journey from infinity to get to a given point C. I cannot say I have a walked from infinity to point C. If my initial destination is an infinite distance away from point C, I would never get to point C since the distance is infinite and shall never end. Similarly, if the universe was created 15 billion years after infinity then that would mean the span of time between the beginning of the creation of the universe and the moment before it is infinite and thus impossible to traverse. This mathematical conundrum has already been discussed far above. Infinity cannot be traversed and arbitrated using a finite set of numbers.
This is why we cannot say when God started to create the universe. We can say it came to be 13.8 billion years ago. "When" is not a concept that can be used to describe God nor His Actions and Attributes, Similarly, "where" is also not a concept that can be used to describe God and His Actions and Attributes. God only and simply exists without a "when" or a "where" for He is Infinitely Eternal. He is Omnipotent. He is Immanent. He is Almighty. He is Forever.
— Promi
Monday, September 8, 2014
Imagining Other Earths — The Grand Universe
At first, this seemed incredibly daunting: to take all of the science we've learned from the ancient Babylonians, the Egyptians, Galileo, Newton, Einstein, the most recent results from the Hubble Space Telescope, and reduce it all to a single sentence.
We sat there for three hours, struggling to summarize all the things that we've done, I think, as any scientists could talk for hours about the importance of their particular contribution. We sat down and we finally came up with a single sentence, the theme of today's lecture, which for me is the most important thing that people should know about astronomy. And that's the idea that the universe is big.
And this is the first of a series of lectures in our class. The class will consist of really three main parts. We'll begin by exploring our own solar system. At the end of that section, we'll have an assignment where you'll write a paper or make a presentation about one of the ideas for building new satellites to explore our solar system.
The second section will be focused on stars and the new planets that we're discovering around these stars. That will end with a assignment where you'll write a paper or develop a presentation on some of the new missions we're hoping to do to discover planets around nearby stars.
And then the final section, we'll return to the Earth and look at the history of life on the Earth, and how it evolved, how evolution works, and then apply those ideas to extrasolar planets, and ponder how life might evolve elsewhere.
The final assignment, I think, will be the most exciting and the most challenging as well. You will create your own solar system. Imagine how life evolves on that solar system. Take some of the lessons we've learned from looking at Mars and Europa and Earth, and apply it to your new planetary system.
I want to begin this course with two introductory lectures. Today's lecture will talk about the universe, and tomorrow's lecture, when we'll talk about the origin of life, what is life, and how we might detect it. Today's lecture, and many of the lectures will consist of several parts, you'll have a segment of about 15 to 20 minutes. That would be followed by one or two short questions, you'll answer those questions then return to the lecture. There'll be another segment of about 15 to 20 minutes, another set of questions, and then the final part of the lecture.
In this lecture and in some others, I'll try to embed some videos that I'd like you to look at, either during the lecture or at the end of the lecture. So let me now begin here and talk about our place in the universe.
We’ll begin first with our own solar system, then turn to our galaxy, and finally look at our place in the universe as a whole. So we're going to start with the Earth. Here we are, on Earth, we're right here in New Jersey. You're spread out somewhere else on this planet. Let's just begin by looking up some basic facts about the Earth.
What I'd like you to do is actually pause the lecture for a moment, go into Google and type in the following things: Earth mass, Earth radius, and how far is the Earth from the Sun? One of the wonderful things about having the web today is you can look up all of the basic astronomical numbers that you might need for any of the problems that we'll look at in this class. So later on, we'll be looking at things like how far is Mars from the Sun. If you want to know that right now, type that question into Google, what will come up is that distance.
Also, all the basic constants of nature, the speed of light, the strength of gravity, all those numbers will come up immediately if you type in gravitational constant or light speed on the web.
This is extremely convenient. In the old days, you would have a textbook for your introductory astronomy class that had a list of all those numbers. Now, they're immediately available to all of you. And I will not be providing them in the questions I'm asking. If you want those numbers, you should look them up. I hope you have.
I want to start with this number, how far is the Sun from the Earth? That distance is what we call an astronomical unit. It's about 150 million kilometers. And, of course, 2 pi times that distance is roughly the distance the Earth travels as it orbits around the Sun. That will be our measure, our ruler for looking at the distance to stars, and for when we talk about other solar systems and we compare how far their planets are from the star.
We will often want to talk about the distance that a planet is from its star in astronomical units. And if a planet is one astronomical unit away from its star, its distance is the same as the Earth from our Sun
Some of the planets we discover by direct imaging, we'll find are 10 or 20 astronomical units away from their star, so they're much further out, they'll be colder planets, much like Saturn or Uranus. The Kepler Telescope has been exploring the inner regions of solar systems, and it has discovered many planets at half an astronomical unit, a third of the astronomical unit, even a tenth of an astronomical unit, much closer to the star than Earth.
Now let's turn to planets. I hope that tonight, you all go out and look for planets. And let me teach you the first thing you need to know to be an expert astronomer: stars twinkle, and planets don't. So when you look at the night sky, if you see something that's bright and flashing and moving, that's an airplane. If you see something that's twinkling, it's a star. The brightest twinkling star you'll see in this time of year, is probably Sirius (not the Prisoner of Azkaban) which is the brightest star in the sky.
And depending on when you look at night, you'll see different planets that are up. Between Venus and Mercury, Mercury is hard to see but Venus is quite bright. Venus is always close to the Sun, so depending on the time of year, you will either see Venus soon after sunset or right before sunrise. Jupiter is the other very bright star, well, bright planet. And, it's often seen directly overhead.
If you want to see what's up in tonight's sky, let me just recommend two websites, http://earthsky.org/tonight and http://ycas.org/tonight_sky.htm. I would encourage you to go look at these websites tonight. Go out and if it's a dark, clear night, see what you can see, see if you can find some planets yourself.
If you have binoculars, I encourage you to look at Jupiter, and if you're lucky, you'll see not just Jupiter, but its massive moons. These moons were first discovered by Galileo when he turned his telescope to the night sky.
When the ancients stared up at the night sky, they noticed that some stars stay fixed, and some, what they thought were stars, moved. They call these ones that moved, wanderers, and those wanderers were planets. And planets, their positions across the sky change, and this change and this motion takes place because while the stars are far away, the planets are close. So the relative positions of the Earth and the other planets move as they orbit around the Sun. And this is why Mars or Jupiter or Saturn appear at different positions in the sky as they move around their orbits throughout the year.
So let me encourage you, and these are questions that I want you to go off and do after lecture, because it requires going, getting away from your computer, stepping outside, and looking at the night sky, see if you find any planets and go stare at the Moon. See what the phase of the Moon is, and watch, over the next month, how it changes.
If you have access to binoculars or small telescope, point it at the Moon. See its craters? It's this remarkable fact that so excited Galileo, that the nearby planets were not perfect. The moon wasn't the perfect surface, but it's this crater structure, those craters, that reflect the whole history of the formation and evolution of the solar system.
So, here's our solar system with the Sun in the center, followed by Mercury, Venus, Earth, and Mars. These are what we call the inner planets. And you'll notice they fill this tiny region. The distance from the Sun to the Earth, our astronomical unit, is much smaller than the distance from the Sun to Neptune. So as we move out, we then have Jupiter, Saturn, Uranus, and Neptune. And the inner solar system is a much smaller region than the outer solar system. This is actually an old figure, and it includes Pluto as one of the planets of the solar system. As I'll argue later, Pluto really ought to be grouped in with the other dwarf planets. Here again is the outer solar system, Jupiter, Saturn, Uranus, and Neptune. And you can see Pluto is different from the others. It's on a very different kind of orbit, much like the other dwarf planets that have been discovered in the past decade. Here's one of them Eris, whose properties are much like Pluto. And Eris is but one of the many objects, in what we call this Kuiper belt made, built off of remnants the formation of the older, early solar system.
This is extremely convenient. In the old days, you would have a textbook for your introductory astronomy class that had a list of all those numbers. Now, they're immediately available to all of you. And I will not be providing them in the questions I'm asking. If you want those numbers, you should look them up. I hope you have.
Planet: Earth
Mass: 5.972E24 kg
Radius: 3,959 miles (6,371 km)
Distance from the Sun: 92,960,000 miles (149,600,000 km)
We will often want to talk about the distance that a planet is from its star in astronomical units. And if a planet is one astronomical unit away from its star, its distance is the same as the Earth from our Sun
Some of the planets we discover by direct imaging, we'll find are 10 or 20 astronomical units away from their star, so they're much further out, they'll be colder planets, much like Saturn or Uranus. The Kepler Telescope has been exploring the inner regions of solar systems, and it has discovered many planets at half an astronomical unit, a third of the astronomical unit, even a tenth of an astronomical unit, much closer to the star than Earth.
Now let's turn to planets. I hope that tonight, you all go out and look for planets. And let me teach you the first thing you need to know to be an expert astronomer: stars twinkle, and planets don't. So when you look at the night sky, if you see something that's bright and flashing and moving, that's an airplane. If you see something that's twinkling, it's a star. The brightest twinkling star you'll see in this time of year, is probably Sirius (not the Prisoner of Azkaban) which is the brightest star in the sky.
And depending on when you look at night, you'll see different planets that are up. Between Venus and Mercury, Mercury is hard to see but Venus is quite bright. Venus is always close to the Sun, so depending on the time of year, you will either see Venus soon after sunset or right before sunrise. Jupiter is the other very bright star, well, bright planet. And, it's often seen directly overhead.
If you want to see what's up in tonight's sky, let me just recommend two websites, http://earthsky.org/tonight and http://ycas.org/tonight_sky.htm. I would encourage you to go look at these websites tonight. Go out and if it's a dark, clear night, see what you can see, see if you can find some planets yourself.
If you have binoculars, I encourage you to look at Jupiter, and if you're lucky, you'll see not just Jupiter, but its massive moons. These moons were first discovered by Galileo when he turned his telescope to the night sky.
When the ancients stared up at the night sky, they noticed that some stars stay fixed, and some, what they thought were stars, moved. They call these ones that moved, wanderers, and those wanderers were planets. And planets, their positions across the sky change, and this change and this motion takes place because while the stars are far away, the planets are close. So the relative positions of the Earth and the other planets move as they orbit around the Sun. And this is why Mars or Jupiter or Saturn appear at different positions in the sky as they move around their orbits throughout the year.
So let me encourage you, and these are questions that I want you to go off and do after lecture, because it requires going, getting away from your computer, stepping outside, and looking at the night sky, see if you find any planets and go stare at the Moon. See what the phase of the Moon is, and watch, over the next month, how it changes.
If you have access to binoculars or small telescope, point it at the Moon. See its craters? It's this remarkable fact that so excited Galileo, that the nearby planets were not perfect. The moon wasn't the perfect surface, but it's this crater structure, those craters, that reflect the whole history of the formation and evolution of the solar system.
So, here's our solar system with the Sun in the center, followed by Mercury, Venus, Earth, and Mars. These are what we call the inner planets. And you'll notice they fill this tiny region. The distance from the Sun to the Earth, our astronomical unit, is much smaller than the distance from the Sun to Neptune. So as we move out, we then have Jupiter, Saturn, Uranus, and Neptune. And the inner solar system is a much smaller region than the outer solar system. This is actually an old figure, and it includes Pluto as one of the planets of the solar system. As I'll argue later, Pluto really ought to be grouped in with the other dwarf planets. Here again is the outer solar system, Jupiter, Saturn, Uranus, and Neptune. And you can see Pluto is different from the others. It's on a very different kind of orbit, much like the other dwarf planets that have been discovered in the past decade. Here's one of them Eris, whose properties are much like Pluto. And Eris is but one of the many objects, in what we call this Kuiper belt made, built off of remnants the formation of the older, early solar system.
This is another way of displaying a map of the solar system. But here we're using what we call a logarithmic scale. So as we move out here, we're looking at factors of ten. The distance from the Sun to the Earth is one astronomical unit, Saturn is ten astronomical units, so on and so forth. And we're using scientific notation here where 10 is written as 10 to the 1 power. The distance out to what we call the terminator, the boundary between the material that we find in the solar system and the interstellar material is about at 100 au.
This year, a remarkable event took place in our exploration of the universe. The Voyager spacecraft crossed the terminator, crossed the boundary between our solar system and the material outside. Now, while it's crossed this point, it still has a very long way to go to get to the nearest star. The nearest star's not 1,000 au, or 10 to the 4 au, the nearest star, Alpha Centauri, is out here at more than 100,000 astronomical units from the Sun.
So you can see the distance to the nearest star is much, much further than the distance to the planets, right? That's a factor of about 10,000. And Alpha Centauri is the nearest star, the typical star we can see in the night sky is often a million, or often 10 million astronomical units away.
Now I'd like to turn to the first problem, and the goal of these problems are twofold. One, it's a chance to improve your quantitative reasoning skills. Two, it's important to sit down and think about some of the concepts that we're talking about in the class, make some rough estimates, and get a feel for some of the numbers we're talking about.
In astronomy, we deal with really big numbers. And I think one of the ways to make sense of them is to start thinking them through. The first question we'll do is we'll look at how long it takes to travel from the Earth to Mars, at their distance of closest approach in a rocket. And to make this problem easier, we're going to keep Mars and Earth fixed. So the way to estimate this is to go look up the Earth's distance from the Sun, look up Mars's distance from the Sun, take the difference between the two, divide by our velocity and figure it out.
You should have found on that problem that it'll take roughly 100 days to travel from Earth to Mars if neither planet moved. The real situation is a bit more complicated: the Earth moves on its orbit around the Sun. Mars moves on its orbit around the Sun. So if we are to travel from Earth to Mars, we'll have to go on one of these transfer orbits. Because the path is somewhat large, longer than moving on a straight line, it will take roughly 200 days to travel from Earth to Mars. This is much longer than the roughly four days that it takes to go, say to the Moon. And because of this longer travel time, this mission is about at the edge of what we can do technologically for the moment today. Here's to hoping for a better tomorrow!
That said, like many people interested in space exploration, I think that Mars is the next obvious destination for human exploration. As we'll see later in the course, there's a tremendous amount that we'd like to learn about Mars. We've gained a great deal of knowledge from our rovers and orbiters that have gone to Mars, but it'd be very exciting to be able to send humans.
This 200-day journey is going to be very challenging. We're going to have to worry about a hostile space environment. And this will be a great challenge, but one that I hope we rise to within our lifetimes.
— Professor David Spergel, Princeton University
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