The big picture is bigger than you think, even bigger than you can imagine.
The Big Picture, An Overview
Let's start with a graph showing the big picture in overview. It's really beyond our intuition's ability to comprehend, so after an overview description of the big picture graph, we'll consider something more familiar, the "small picture." We'll gradually work back up to the big picture, using small picture concepts - dragging our intuition along for a ride it's never taken.
Figure 1. Diameter of the universe versus time, from the "big bang" beginning to the "evaporating end." The X-axis is logarithm of time, in years. The Y-axis is logarithm of size, in meters. The numbers refer to significant events, described below.
This daunting figure will gradually reveal its meaning. The beginning of everything, the "Big Bang" begninning, is at the left-most point of the red line in this figure. It is located after the shortest time interval that can be imagined, called the Plank Time. This increment of time is "one quantum time unit," or 4x10-44 seconds.
About 300,000 Plank Time quanta later, the universe commences to expand exponentially. This is called the "inflationary expansion period." It lasts about 10-32 seconds. Afterwards, the universe expands linearly with time, indicated by a straight line in this log-log plot.
At (1) the "electroweak force" and the "electromagnetic force" separate, and become capable of exerting their influence over the motion of nuclear and larger scale particles, respectively.
(2) is a significant event, because quarks begin to come together (in two's and three's) to form protons, neutrons and other particles (and are held together by gluon particles). This happens at about 10 microsecond after the big bang. Now the electroweak force has a job to do.
(3) is when light elements begin to be synthesized, thanks to the electroweak and nuclear forces. This time is 100 seconds after the big bang.
At time (4), or 300,000 years after the Big Bang (BB) birth, electrons and protons have slowed enough to allow hydrogen atoms to form. This greatly reduces the number density of free electric charges (a plasma), and this allows photons to move much longer distances without being absorbed by the plasma. The 2.73 K "cosmic background radiation" is set free at this point, and is currently being studied assiduously, allowing credible stories to be told of the first moments of our universe.
The first star begins to form at (5), a million years after the BB.
At (6) the first galaxies begin to form, 600 million years after the BB.
Our sun has the required luminosity for keeping the Earth warm enough to sustain life for such a brief period, from 9 billion to 18 billion years after the BB. These two times are so close together on the scale of this graph that they appear as one mark, at (7). The green square is placed here to signify where we are today. This green box will be dealt with later in this web page.
At (8) the last red dwarf dies, all other (more massive) stars having died out earlier. This occurs 100,000 billion years after the BB, which is essentially the same as 100,000 billion years after now (technically, 999,990 billion years from now).
At (9) most planets will have become detached from their parent stars and will be roaming freely between the field of now-dead stars.
Soon after, at (10), most stars ("burned out" former stars) will have detached from the galaxy they once were securely a part of.
At (11) the remaining dark white dwarfs will absorb and deplete WIMPS that used to be part of the the galactic haloe. WIMPS are "weakly interacting massive particles," 10 to 1011 times more massive than protons; they hypothesized existence is needed to explain the "missing mass" that constitutes 95% of the mass of the universe, making ours a universe teetering between "closed" and "open."
At (12) black holes will accrete the remaining dark white dwarfs and neutron stars from volumes of space comparable to galaxy-sizes.
At (13) black holes will accrete the remaining dark white dwarfs and neutron stars from volumes of space comparable to the size of galaxy clusters.
(14) is a "bummer," for this is when protons will decay, and nothing made of atoms will remain!
Axions decay into photons at (15).
At (16) the only remaining concentrations of mass are black holes.
By (17) stellar-size black holes will have evaporated.
And by (18) million solar mass black holes will have evaporated.
Finally, at (19), galaxy-size black holes will have evaporated. Thus begins an "empty" universe era.
At (20) positronium (electrons and positrons) will come together in orbit around each other, and eventually spiral together and decay.
Unknown physics takers over at (21), but you can be sure that intelligent life won't be produced by it.
[The sequence described above was adapted form an article by Fred C. Adams and Gregory Laughlin in Sky and Telescope, August, 1998.]
Another way to view this immense expanse of time, and space, is to convert from te log-log scale to Linear-Linear:
The First Few Billion Years
The following figure depicts both space and time with "linear" scales.
Figure 2. Representing an expanding 3-dimensional universe using 2-dimensional planes offset in time.
I shall make use of a "dimension collapsing" trick for representing
a 4-dimensional situation using a 2-dimensional diagram, illustrated above.
The two yellow ovals in the figure are used to represent our 3-dimenional
world at times "t1" and "t2". The dots can
be thought of as galaxies, and since the universe is expanding the galaxies
are expanding away from each other with time. It will be convenient
in subsequent diagrams to collapse one more space dimension, corresponding
to changing the ovals (that appear to have 2 dimensions) to vertical lines
(having 1 dimension). This is done in the next figure.
Figure 3. Linear-linear scale for space and time, but showing only that part of space/time out to 20 billion years. The red lines show the diameter of the universe; the green symbols show events specific to the earth.
This figure's linear scale doesn't have room for the first 5 events of the first figure (illustrating the merits of log-log plots). But this linear-linear plot will serve our present purpose better, for we wish to emphasize our little world's place in the universe. An event that might concern us is the predicted evaporation of the oceans a billion years in the future, caused by the sun's slow increase in luminosity. The Earth will be lifeless after that time (unless something heroic is done beforehand). Another threat to the earth is the approach of the Andromeda Galaxy (M31), which is expected to reach us in 3 billion years. This may not affect the earth, but it might sling our sun and solar system (and many other suns and their solar systems) out of the galaxy. If we survive that, then there's the sun's gradual expansion to worry about, reaching approximately the earth's orbit; but this won't happen for another 5 billion years. Considering these dire future events it would be quite optimistic to believe that humans will exist for more than a billion years (on earth).
Figure 3 is a very, very small portion of the entire universe that shall ultimately exist. For example, the next event portrayed in Fig. 1 after "now" is "8" ("last red dwarf dies"), which for Fig. 3 would be located 3 feet to the right (viewing Fig. 3 with a typical screen size). And just to drive the point home further, event #9 (from Fig.1) would be located 500 miles to the right!
As small a part as Fig. 3 is of the entirety of Fig. 1, it will nevertheless serve us better for the task of bridging the gap between what we're familiar with and something that is more closely related to the big picture (Fig. 3). Our task, now, is to build up from the world with which we are familiar to the portion of the universe portrayed in Figure 3.
Another Perspective, the Small Picture
Consider a crawling bug living a brief life on a 2-dimesional world.
Figure 4. Lifetime path of a 2-dimensional world of a crawling bug.
The bug is born at "A" and dies at "B" after traveling a modest path in its 2-dimensional world with x-y coordinates.
Figure 5. Lifetime path of a 2-dimensional world of a crawling bug with time "dimension" added. The bug's life lasts dt time units.
The duration of the bug's life in the time dimension is dt time units. The bug's life occupies a volume of 3-dimensional space/time bounded by the "cube" shown above. This is the bug's universe. It has no direct experience with anything outside its cube.
The bug's lifetime cube is a subset of larger cubes, as indicated below.
Figure 6. Bug's cube in relation to a larger space/time portion of the universe.
Every creature will have a lifetime cube. Obviously, a human's will be larger in both space and time than a bug's. Some people will have larger lifetime cubes than others. But wait a minute, I'm talking as if people lived on a flat world. Let's worry a little about this concept.
Whereas it may be appropriate to confine a bug to a flat, 2-dimensional world, all creatures really live in a 3-dimensional world, plus time as the 4th dimension. It was merely a graphical convenience to confine the bug to a flat world, because it allowed us to portray its passage through time as an upward movement through a time dimension. In other words, we usurped a space dimension for the purpose of representing time. We did this by collapsing one of the bug's dimensions, the vertical one, thus rendering it available for replacement by "time."
This collapsing operation didn't bother you because we can easily imagine a bug living a life confined to a flat world. To help you feel comfortable with this business of collapsing dimensions, let's return to the bug example, and perform one more collapsing operation. Look at Fig. 5 again. We can compute the maximum distance spanned by the bug's path by considering all possible pairs of points along its lifetime path and noting which is the biggest value. For the example in Fig. 5 it looks like the distance between "A" and "B" (by convenient coincidence). Let's call this distance dS, and refer to this "maximum distance spanned" as the "wandering span."
We've just collapsed the bug's world into just one spatial dimension. It's movement through a our initially hypothesized flat, 2-dimensional world has been converted to movement along just one dimension. The new spatial dimension just defined goes from one extreme location along its life path to another extreme location along its life path. For the specific case under consideration, shown in Fig. 5, the new spatial dimension goes through the points "A" and "B." The method for doing this is well specified. It can be done for any life path. A person born in Michigan, for example, who settles in California (and does no other travel), has created a spatial dimension that goes from Michigan to California. Moreover, that person can be said to have a "wandering span" equal to the 2000 miles between Michigan and California.
Consider the following diagram.
Figure 7. Space/time domain, where we can place a creature's life cube with collapsed space dimensions.
The red rectangle has a time width corresponding to a creature's lifespan, dt. Likewise, the red rectangle's vertical height corresponds to the creature's wandering span, dS. The location of the red rectangle is arbitrary. In the case of time, once we've chosen a "zero" for time, any other creature's rectangle will have a specified location along the time axis. In the case of the spatial distance dimension, things are confusing, given my abbreviated procedure for collapsing spatial dimensions. I will merely state, without proving, that any specified method for collapsing orthogonal spatial dimensions will lead to well-behaved collapsed dimensions, such that movement in the original space translated unambiguously to movment along the collapsed dimensions. Thus, it is possible, mathematically, to collapse the 3-dimensional world into a single dimension, along which all actual movements can be translated without arbitrary or ambiguous offsets.
By collapsing a person's 3-dimensional wanderings to a 1-dimensional wandering, we are able to convert a lifetime path to a well-defined rectangle in a "time/spatial distance" diagram, as in Fig. 7. Two such life paths can be compared to each other, as in the next diagram.
Figure 8. Space/time domain,showing the locus of points describing life paths for two creatures.
This figure shows two creature's life paths. The more expansive "green" creature died at about the same time as the "red" creature. They never could have encountered each other even if they had lived at the same time, because their spatial ranges don't overlap. You may think of the red creature as a bird, for example, and the green creature as a person living elsewhere on earth. The person hasn't travelled the world extensively, or else the spatial range of green would include that of red.
Most people live a normal lifespan, so plotting green rectangles for many people wouldn't provide much range of widths. However, people do vary in the extent of their travels. The next figure illustrates this.
Figure 9. Space/time domain,showing a bird and two people. Person "blue" is well travelled.
Later in time a person exists who travels more, represented by the blue rectangle in this figure. He lives a shorter life, but his greater travels makes his life more noticeable in this diagram.
By now you have intuited that the vertical axis spans approximately the earth's diameter, and the horizontal axis spans approximately a 1000 years. We need to cover more space and time if we're ever going to return to Fig. 3 with a better understanding of its meaning. So, let's try to accomodate an Apollo astronaut, whose travels to the moon and back constitute a wandering span of 384,000 km. We'll have to increase the vertical axis distance range by a factor of 30, and let's label it using meters instead of arbitrary units. Let's also try to accomodate a bristlecone pine tree, that can live 4000 years. We'll have to expand the range of the time axis, and in doing this let's label time in years.
Figure 10. Space/time domain,with enlarged distance and time range to accomodate an Apollo astronaut and bristlecone pine tree. The astronaut is represented by the tall red rectangle. The bristlecone pine tree is the long horizontal green line, having a height too narrow to discern (a few meters). The red dot, barely visible, is the bird, and the two men from the previous figure can also be seen.
In this figure we have the two extremes of earth life: 1) an Apollo astronaut, representing the life form exhibiting the most distant travel, and 2) the bristlecone pine tree, representing the life form having the longest longevity.
If you, dear reader, are well-travelled, your life is contained in a rectangle the size of the small blue rectangle 1.4 mm wide, by 2.3 mm tall, if you're a "well-travelled man".
Figure 11. 100 times larger range, for both time and distance, compared with last figure. The tiny box around the origin represents the size of the time/distance range of the previous figure. The astonaut and bristlecone pine lines are barely visible (close to the origin). The series of interglacial warmings are shown as short magenta lines (just below the distance = 0 level). The mark at 200,000 BC is an approximate time for the split between caucasians and negroids; shortly afterwards the asians split from the caucasians. At 28,000 BC the Cro Magnon race (caucasians) completed their theft of Europe from the Neanderthals, thus finalizing a million year process of competition between many humanoid species, leaving just one winner species with three major races. At a good "inferior conjunction" Venus comes to within about 39 million km of Earth.
A person's life occupies a space so small in this figure that its corresponding "dot" would be invisible unless a microscope were used (14 by 23 microns). The entirety of recorded history would be a line about half the length of the magenta line segment denoting the most recent "interglacial" (that extends from 11,000 BC to the present). You can be sure that in the next figure there will be no trace of Humanity's magnificent strutting upon the Earth!
Figure 12. 20 times larger range, for both time and distance. The small box enclosing the origin represents the distance/time extent of the previous figure. The glacial period, with interglacial warmings, is barely discernible to the left of the origin. Along the zero-distance line are marks for when the human ancestral line split from that of the orangutan, gorilla, ape and A. afarensis (earliest pre-human). At 1.75 million years ago the human brain underwent a rapid expansion, followed by the control of fire. The distances to Venus, Mars and Jupiter, at closest approach, are indicated along the zero-time axis, as is the nearly constant distance to the sun.
You, the "well-travelled man," live in a wolrd that is now 0.7 microns wide by 1.1 microns tall in this figure (slightly larger than a cell nucleus).
Figure 13. Approximately 30 times larger range, for both time and distance. The small box enclosing the origin represents the distance/time range of the previous figure. Along the time axis are shown when primitive reptiles and the first dinosaurs evolved, the first mammals, when the supercontinent Pangea began to break apart, when the dinosaurs were exterminated by an asteroid, when the lemurs evolved away from the shrew lineage, when continental drift began to separate America from Europe, and when apes evolved away from the lemur lineage. The distances to Jupiter, Saturn and Pluto are indicated along the zero-time axis.
It is worth noting that reptiles have existed for most of the time span of this figure, whereas humans have existed less than 1% of it. Shortly before the time spanned by this figure the continents had coalesced into one large supercontinent, Pangea, and they began their breakup into two supercontinents near the middle of the period spanned. These two supercontinents, Laurasia and Gondwanaland, commenced their break up (with some "collisions") at about the middle of the figure.
The world of our "well-travelled man" is 230 Angstroms wide by 370 Angstroms tall. Let us suppose that Future Man achieves a form of immortality that allows him to live a million years, and that his travels take him throughout the solar system. Future Man's world would then encompass a box, in hte above fiure, about 1 millimeter wide by 20 millimeters tall. From now on we shall identify with Future Man!
Figure 14. Approximately 20 times larger range of time, 100 times larger range of distance. As before, the small rectangle surrounding the orogin, now squished vertically due to the greater distance zoom, represents the time/distance intervals represented by the previous figure. There's so little between our solar system and the stars that "empty space" is the only notation worth mention in this figure. However, notable events are present during the time interval covered by this figure. The solar system formed, life on earth started, oxygen build-up occurs in ouratmosphere, and continents breakup and reform as Pangea.
The world of the "well-travelled Future Man" is now 50 microns wide by 200 microns tall.
Figure 15. Only 3 times larger in time, but 20 times larger range. The box including the origin represents the coverage of the previous figure. Along the distance axis we finally have something to plot, the nearest star Proxima Centauri. The bottom of the figure corresponds to a distance of 9.5 light years, within which there are a mere 10 stars.
In the next figure we shall change the origin for the time scale, setting "zero" to the beginning of the universe. Also, we shall leave the time scale the same while increasing the distance coverage by a large amount. The range of distances covered will increase by a factor 10,000. Space is so large that we need to do this to make progress toward adjusting our scales to be in alignment with Fig. 3.
The world of the "well-travelled Future Man" is now 17 microns wide by 10 microns tall, the size of a lmphocyte cell in the blood.
Figure 16. Same time scale, but with "zero" set to correspond to the birth of the universe. The distance scale covers a 10,000 times greater range than the previous graph.
With this distance scale we can portray our galaxy conveniently, as with the following image, constructed from COBE (Cosmic Background Explorer) satellite IR data (from a web site that acknowledged Ned Wright for creating the image).
The "well-travelled Future Man's" world is now as tall as 10 Angstroms, or the height of several average molecules.
Figure 17. Image of our Milky Way galaxy, created from COBE IR data.
We're approaching the Fig. 3 scales. The only adjustments left are vertical, distance scale changes.
Figure 18. Same time scale as in the previous figure, but 30 times more distance coverage. The Andromeda Galaxy is the closest galaxy to ours (aside from our galaxy's satellite mini-galaxy, the Large Magellanic Cloud). The green ovals represent the diameters of our galaxy and the Andromeda galaxy, with sizes to the proper distance scale. The thick dashed green line represents the closing of the distance between the Andromeda Galaxy and our own galaxy, leading to a possible collision in 3 billion years.
Figure 19. Illustration of sizes in relation to separation of our galaxy and our nearest neighbor, the Andromeda galaxy (photos of M51 and M31 by Jason Ware).
The image above shows the sizes of our galaxy (represented on the left by a portion of M51) and our nearest galaxy neighbor, the Andromeda galaxy, in approximate proportion to the distance between them. In preparing this web page I was struck by how close galaxies can be to each other in relation to their size. The Andromeda galaxy and ours are moving together at 500,000 km/hr, and the two may "collide" in one billion years.
The "well-travelled Future Man" inhabits a world that on this scale as tall as a hydrogen atom.
Figure 20. Same time scale, but 100 times greater coverage by distance scale (vertical axis). The Andromeda Galaxy is not plotted because it would be too close to the Earth symbol. However, the more distant Virgo Cluster of galaxies is shown, as well as a "supercluster" of many, many galaxies. Superclusters are the largest structures known to exist in the universe, and they are approximately 250 million light years across. The yellow circle's vertical dimension represents this size. The edge of our universe is shown by the red lines on the left.
In this figure the Andromeda Galaxy is 100 times closer to us because of the distance scale change, and is not plotted because it is too close to the "here & now" symbol. The Virgo cluster of galaxies is 20 times farther away, and is plotted. Superclusters of galaxies are the largest known structures in the universe; they consist of galaxies and clusters of galaxies. There are many superclusters of galaxies in our universe.
Dear Future Man, your world is now diminished to the size of the nucleus of the largest atom.
Figure 21. A factor of 10 increase in distance coverage, showing many superclusters of galaxies.
In this figure the edge of the universe has a more noticeable slope, and more superclusters of galaxies can be seen.
Future man's world extends as high as a proton is wide.
Figure 22. Another factor of 10 times larger distance
coverage. The "edge" of our universe is indicated by the red lines.
The Earth, at the present time, is depicted by the bright violet circle
at 13 billion years (along the x-axis). There could be 30 superclusters
between us and both (all) edges of the universe (not shown).
With this last 10-fold increase in the distance covered by the figure's vertical axis we have finally arrived at the same scales as in Fig. 3!
Note: The age of the universe has just been determined to be 13.7 billion years, with an accuracy of 1%, based mostly upon satellite-measured spatial fluctuations of the 2.73 K cosmic background radiation. Please substitute 13.7 billion years for 13 billion years wherever it appears on this web page. 2003.02.20.
It is theoretically impossible to see anything, or know about it, that is beyond the edges of the universe. Everything in the universe that we can know about is a subset of the area (volume) formed by the red line edges of the universe and the vertical "now line" at 13 billion years. In fact, we cannot know about things at the edges of the universe at the present time, since light from there is just starting its journey to Earth. The "knowable universe" is therefore limited to a volume depicted in the next figure.
Future Man's solar system journeys fit inside a proton, and his dreams of travelling to the nearest star would extend his world to a height that on the scale of the previous figure would almost reach the innermost electrons from the nucleus of a typical atom.
But wait! Even though a "reprise" is a good place to end something, this story isn't over yet. For the last figure isn't the big picture - not yet. Consider expanding both time and distance scales by a factor 10.
Figure 23. Both scales are expanded by a factor of 10, compared to the previous figure.
We're not done yet!
Figure 24. Both scales are expanded by a factor of 10, compared to the previous figure.
We haven't even reached #8 in Fig. 1, when the last red dwarf dies. This factor of 10 expanding process would have to be done another 108 times just to reach the limits shown in Fig. 1. And then we could continue, and continue ... forever!
Yes, the universe is bigger than you think, even bigger than you can imagine!
This site opened: July 27 2000. Last Update: February 20, 2003