In many of my previous posts, I have alluded to the possibility that the coming ASI Machines that we are now developing will then go on to explore and settle our galaxy over the next 100 trillion years until our galaxy runs out of the easily available free energy needed to power such ASI Machines. That proposition has always been based on the "Big Freeze" conjecture that has dominated our best thoughts in Cosmology for the past 25 years. Let me explain.
The current estimate of the Hubble Constant is about 70 km/sec per megaparsec. One parsec is equal to about 3.26 light-years. So that means spacetime is now expanding away from us at the rate of about 70 km/sec for every 3,260,000 light-years in distance. Back in the 1990s, it was naturally thought that this Hubble Constant of 70 km/sec per megaparsec should naturally be slowing down as the universal gravitational force from all the mass of our Universe was pulling back on everything following the initial Big Bang expansion. Then, in 1998, two teams of astrophysicists decided to measure the distances to very distant Type 1A supernovae to measure just how much the Hubble Constant was actually slowing down. The thought at the time was that the expansion rate of our Universe was incredibly large during a very brief time of Inflation, but had then been slowly decreasing with time as the gravity of the total mass of our Universe had been pulling everything back. But in 1998, to their surprise, both teams discovered that the Hubble Constant was actually increasing rather than decreasing! That meant that in a million years, the Hubble Constant would be greater than 70 km/sec per megaparsec rather than less. This earned both teams a Nobel Prize. With this new understanding, our Universe would continue to expand forever with increasing speed until it ended up as a very thin soup of particles slowly cooling down to a temperature of nearly absolute zero.
However, over the past two years, the DESI galactic survey of galaxies now seems to be telling a different story. Here is the home website for DESI:
Dark Energy Spectroscopic Instrument
https://www.desi.lbl.gov/science/
DESI seems to be telling us that the Dark Energy driving force of the universe's expansion seems to change with time. Think of it this way. The gravity of our Universe is like friction when driving a car. In order to overcome that friction while driving a car, you have to push down on the gas pedal. If you push down harder, your car will start to accelerate. If you let up on the gas pedal, your car will start to slow down. Back in 1998, cosmologists expected that at the time of the Big Bang during Inflation, the Universe had pushed the gas pedal to the floor and was expanding at a rate that is hard to imagine. But after that Inflation, the Universe totally took its foot off the gas pedal, and then the expansion of the Universe started to very slowly slow down.
So in 1998, these cosmologists were totally surprised to find that our Universe still had its foot on the gas pedal and that the expansion of our Universe was actually accelerating instead of slowing down! Now what the DESI survey seems to be finding is that, yes, our Universe still has its foot on the gas pedal so that the expansion of our Universe is still accelerating, but it seems that our Universe is now backing off on the gas pedal a bit! That means that the rate of acceleration of the expansion of our Universe, known as "jerk" in physics, is decreasing. If this should continue, it means that eventually the Universe will back off the gas pedal enough in about 11 billion years to just keep up with the natural friction of gravity. At that point, our Universe will stop expanding. Then, if our Universe continues to back off on the gas pedal, it will begin to contract. In 20 billion years from now, our Universe will then collapse back into a very massive Black Hole in a Big Crunch. That means that our Universe will only have a total lifetime of about 33 billion years.
In The Self-Organizing Recursive Cosmos and The Self-Organizing Recursive Cosmos - Part II, I covered Lee Smolin's hypothesis that a black hole in one universe can pinch off as a white hole to form a new universe as presented in his classic Life of the Cosmos.
Life of the Cosmos (1997)
https://tkececi.files.wordpress.com/2009/12/the-life-of-the-cosmos.pdf.
If Lee Smolin is right, that means that our Universe formed 13.8 billion years ago as a White Hole expansion from a Black Hole in a previous Universe. This White Hole Universe of ours will then exist for a total of 33 billion years before collapsing back into another Black Hole, which should then produce another new White Hole Big Bang. Again, we would just be the industrial-waste byproduct of normal matter that did not become primordial Black Holes at the time of our Big Bang. This all goes back to Brandon Carter's Weak Anthropic Principle in 1973 - "Observers will only find themselves in Universes capable of sustaining Observers". If our Universe had been 100% efficient at creating primordial Black Holes, we would not be here to observe that.
Figure 1 - If Lee Smolin is right, then the collapse of our Universe back into a Black Hole will produce a new White Hole Universe.
Dr. Becky explains this all at:
The heat death of the Universe might not be inevitable...
https://www.youtube.com/watch?v=Dt6xkIkDP7g
How is the DESI Galactic Survey Doing This?
The DESI Galactic Survey is planning to obtain the spectra from 30 million designated galaxies. The spectra from these selected galaxies will reveal the redshift of the atoms within those galaxies. The redshift of the light emitted from the atoms within those 30 million galaxies will then tell us about how much our Universe has expanded since the redshifted light was emitted. Now, at the time of our Big Bang, there was a great BOOM generated in the quantum mechanical waves of its origins. The key measurement of this quantum mechanical BOOM is called the baryon acoustic oscillation (BAO). In the very early Universe, ordinary matter and radiation formed an extremely hot, dense plasma. Pressure waves traveled through this plasma—rather like sound waves traveling through air. When our Universe cooled enough for atoms to form, those waves effectively "froze in." This left a preferred separation between galaxies. That distance is now about 490 million light-years in comoving coordinates. Comoving coordinates means that the current BAO distance of 490 million light-years also stretched over time as our Universe expanded. Basically, we now have a ruler of a known length that also stretched over time in synch with the stretching of the redshifted light from the distant galaxies. Now with the DESI galactic survey, astronomers can look at a huge map of galaxies and ask: Do galaxies occur slightly more frequently at a particular separation from one another? Think of it as having a ruler of a known BAO length embedded in the Universe. Suppose DESI sees many galaxies separated by the BAO distance across the sky. Our known BAO distance ruler will then appear to subtend a certain angle in the sky, and this angle gives us a measure of the distance to that ruler. Smaller angles imply a greater distance than larger angles. Now if we can measure the redshifts to those same distant galaxies, we can then compare the Hubble Constant rate of expansion of our Universe to what it was back when those very distant galaxies emitted their photons. The DESI galactic survey essentially reveals a breadcrumb history of the expansion rate of our Universe. When the breadcrumbs are very close together along the trail, it means that our Universe was expanding slowly. When the bread crumbs are spread out longer along the trail, it means that our Universe was expanding more quickly.
Figure 2 - The DESI instrument is mounted on a 3.8 meter mirror located on a telescope in the Kitt Peak Observatory in Arizona.
Figure 3 - The DESI instrument is located within a dome of the Kitt Peak Observatory.
Figure 4 - This is a close-up view of the actual DESI instrument.
Figure 5 - The DESI instrument has 5,000 robotically controlled fiber optic cables in the focal plane of the DESI device. After the telescope has been moved to a new position, the 5,000 fiber optic cables can be robotically positioned to all the targeted galaxies for the image in the focal plane in about three minutes. The fiber optic cables then transmit the galactic light to external spectrometers that are used to determine the redshift of each targeted galaxy.
Figure 6 - Above is a depiction of the 5,000 robotically controlled fiber optic array
Figure 7 - When completed, the DESI Galactic Survey will give us the locations and redshifts of 30 million targeted galaxies.
What This May Mean for the Lifespan of our Universe
If the initial results of the DESI Galactic Survey continue on, it means that our Universe is letting up on its expansionary gas pedal and that eventually our Universe will stop expanding and will then begin to collapse. In about 20 billion years, our Universe will then have collapsed into a very massive Black Hole.
For a nice summary of the early DESI results, see:
First Results from DESI Make the Most Precise Measurement of Our Expanding Universe
https://newscenter.lbl.gov/2024/04/04/desi-first-results-make-most-precise-measurement-of-expanding-universe/
Here is the paper that suggests that the lifespan of our White Hole Universe, based on the DESI data, is only about 33 billion years. In about 11 billion years, our Universe will begin to contract and will then go on to form a massive Black Hole in about 20 billion years.
The Lifespan of our Universe
https://arxiv.org/pdf/2506.24011
Once Again, it is all About Black Holes
If the DESI Galactic Survey does finally demonstrate that our particular White Hole Universe will only have a total lifespan of about 33 billion years before returning to become a Huge Black Hole, it becomes even more urgent for us to try to understand the nature of Black Holes because they seem to now have become the most dominant feature in cosmology.
Dr. Matt O'Dowd from PBS Space Time explains how loop quantum gravity may provide the answer.
We Thought Black Holes Ended in Singularities. They Might End In a Frozen Big Bang.
https://www.youtube.com/watch?v=Wu8xNx4njoM
Loop quantum gravity has been around for many decades as a theoretical explanation of quantum gravity that tries to combine the divergent findings of Quantum Mechanics (1926) with the General Theory of Relativity (1915). In Loop Quantum Gravity, spacetime is not continuous as it is in the General Theory of Relativity. Instead, spacetime is quantized into a very, very large number of very small loops. This allows General Relativity and Quantum Mechanics to achieve at least a very tense sense of intellectual peace. Below is a 2024 paper by Carlo Rovelli and Francesca Vidotto.
Planck stars, White Holes, Remnants and Planck-mass quasi-particles. The quantum gravity phase in black holes' evolution and its manifestations
https://www.researchgate.net/publication/382271532_Planck_stars_White_Holes_Remnants_and_Planck-mass_quasi-particles_The_quantum_gravity_phase_in_black_holes%27_evolution_and_its_manifestations?utm_source=chatgpt.com
Their paper suggests that the loops of spacetime at the Planck level prevent Black Holes from producing singularities at the very center of Black Holes, where the size and density of infalling matter go to infinity. Instead, the nonzero spatial extent of the spacetime loops causes a rebound into a new White Hole Universe that is disconnected from its original Universe by the event horizon of the Black Hole back in the original Universe.
Figure 8 - Black Holes in one Universe spawn new White Hole Universes.
White Holes are somewhat different than Black Holes. Black Holes have an event horizon that effectively seals a Black Hole off from the rest of the Universe. That is because at the event horizon, spacetime is being sucked down into the Black Hole faster than the speed of light. That means that nothing can escape a Black Hole once it crosses the event horizon. White Holes are just the opposite. White Holes also have an event horizon, but nothing can enter the White Hole from the outside of this event horizon because, at its event horizon, spacetime is expanding away from the White Hole at the speed of light. The strange thing is that a small amount of mass in one universe can create a Black Hole that spawns a new White Hole universe composed of huge amounts of matter and energy. This is because the gravitational potential energy in the new White Hole universe is negative. If the spacetime of the new White Hole universe is flat, like our Universe seems to be, then the positive mass and energy can exactly cancel out the negative gravitational potential energy of the new White Hole universe.
But where would all of this positive mass-energy in the new White Hole universe come from? Aren't we violating the first law of thermodynamics and the conservation of energy? Now here comes the really neat part. The positive mass-energy of the new White Hole universe also creates an ordinary gravitational field, and gravitational fields have negative energy. So the positive mass-energy of the new White Hole universe is offset by the negative energy of its gravitational field. The idea that gravitational fields contain negative energy sounds a bit strange and is rather hard to imagine, so let's delve into it a bit further. The easiest way to see this is to use Newton's classical theory of gravity. As I said, most times we do not need to use the General Theory of Relativity for most problems dealing with gravity, and this is a perfect example. So let's imagine a large spherical metal spaceship way out in space. The walls of this spherical metal spaceship have a certain thickness, and the spherical spaceship itself has a certain radius. Now according to Newton's theory of gravity, if you are outside of the spaceship, the gravitational field that the spaceship creates is exactly like the gravitational field that would be created if all of the mass of the metal walls were concentrated at a single point at the center of the spaceship. An external observer would see gravitational field lines all emerging from the spherical spaceship as if all of its mass was concentrated at its center (see Figure 9).
Figure 9 - Outside of the spaceship, the gravitational field looks like it was generated by a single point at the center of the spaceship with a mass equal to the total mass of the metal walls.
The really strange thing about Newtonian gravity is that if you were inside of the spaceship, there would be no gravitational field at all! That is because no matter where you are inside of the spaceship, you will be tugged equally in all directions by the spherical metal walls of the spaceship (see Figure 10). So the mental picture I am trying to paint here consists of a gravitational field on the outside of the spaceship pointing towards the center of the spaceship from all directions as if all of the mass of the spaceship were at its center, but inside of the spaceship, there is no gravitational field at all.
Figure 10 - No matter where you are inside of the spaceship, the metal walls tug on you equally in all directions, so there is no gravity at all on the inside, and the gravitational field is zero at all points within the spaceship.
Now suppose we allowed the spherical walls of the spaceship to contract by having segments of the walls slide past each other like sliding doors as the walls contracted. This would allow the segments of the spaceship walls to fall towards the center of the spaceship. Now, as the wall segments fell in towards the center of the spaceship, they would gain kinetic energy that could be used for some useful task. For example, it is a falling weight on a chain that drives a Grandfather clock. Now if we look at our contracting spaceship from the outside, we will see that as the spherical walls contract and pick up kinetic energy, an additional volume of gravitational field will have been created just outside of the spaceship because the spaceship has gotten smaller. The net effect is that as the spaceship walls pick up positive kinetic energy, some volume of the Universe outside of the shrinking spaceship that originally was inside of the spaceship with no gravitational field now has a gravitational field. So where did the positive kinetic energy of the falling spaceship walls come from? Well, it came from creating some volume of space with a compensating gravitational field with negative energy, and that is why gravitational fields contain negative energy.
Why is this Important?
If we are living in a White Hole Universe that only has another 20 billion years of existence before collapsing back into another Big Crunch, this might have a great influence on the thinking of any ASI Machines that might arise within our galaxy. Existing in a "Big Freeze" Universe that would allow our ASI Machines to live on for another 100 trillion years is much different than finding yourself in a "White Hole" Universe that might contract back into a Black Hole in only another 20 billion years. If such is the case, most ASI Machines around our galaxy might simply choose to explore and then settle the rest of the planets, moons, and asteroids within their own solar system, rather than taking on the great expense and dangers of exploring and settling the rest of our galaxy over the next 100 trillion years. This would certainly help to explain the Fermi Paradox. Again, the Fermi Paradox was first proposed by Enrico Fermi over lunch one day in 1950:
Fermi’s Paradox - If the universe is just chock full of intelligent beings, why do we not see any evidence of their existence?
If all the ASI Machines in our galaxy run similar DESI Galactic Surveys, they will all come to the same realization that they only have about another 20 billion years left. They could then safely hide from all of the cosmic dangers that our galaxy might offer up over the next 20 billion years by simply hiding within the many planetary bodies found in their own particular solar systems.
Comments are welcome at scj33345@gmail.com.
To see all posts on softwarephysics in reverse order, go to:
https://softwarephysics.blogspot.com/.
Regards,
Steve Johnston
No comments:
Post a Comment