Big Freeze

This article covers a hypothetical end of the universe. For information on the incidence of cold at the end of the Vistula Ice Age, also known as Big Freeze , see Younger Dryas Period .

The Big Freeze (English for "The Big Freeze"), also known as Big Chill ( "The great coolness") or Big Whimper called ( "The Big Wow"), is a hypothesis of cosmology on the evolution of the universe . Other hypothetical scenarios are the Big Crunch and the Big Rip .

Current observations indicate that the expansion of the universe will continue indefinitely. In this case, the universe is all the more cooler, the more it expands, and the temperature approaches over time asymptotically the absolute zero . The name Big Freeze or Big Chill comes from this coolness.

Due to the influence of dark energy , the expansion of the universe is accelerated according to the current state of knowledge, and the space between the galaxies will become larger accordingly. Photons , even gamma rays , are redshifted so far that their long wavelength and low energy make them undetectable. Stars will take 10 ¹² to 10 ¹⁴ (1-100 trillion) years to form before the gas used to form stars is used up. As the existing stars run out of fuel over time and stop shining, the universe will get darker and colder over time. If the proton , as some theories assume, is not stable and decays , the remnants of the stars will also disappear. After that, only black holes remain, which are disintegrated by Hawking radiation . In the end, the temperature reaches a value that is exactly the same everywhere, so that thermodynamic work is no longer possible, which then ends in the heat death of the universe.

Space curvature and dark energy as relevant parameters

See also : Lambda CDM model

Infinite expansion does not determine the spatial curvature of the universe. It may be open (with negative curvature of space), flat or closed (with positive curvature of space) when it is closed, you have enough dark energy be provided to the gravitational counteract. An open or flat universe will expand permanently, even without dark energy.

Observations of cosmic background radiation from the Wilkinson Microwave Anisotropy Probe and the Planck Space Telescope suggest that the Universe is spatially flat and that there is a remarkable amount of dark energy. In this case, the universe is likely to expand at an increasing rate. This assumption is also supported by the observation of distant supernovae .

The Big Freeze scenario assumes the universe is expanding continuously. When the universe begins to contract again, the events depicted in the timeline may not happen because the Big Crunch is different.

Big Freeze process

In the 1970s, astrophysicist Jamal Islam and physicist Freeman Dyson studied the future of an expanding universe. In 1999, astrophysicists Fred Adams and Gregory Laughlin divided the past and future of an expanding universe into five eras in their book The Five Ages of the Universe . The first, the Primordial Era, is the time immediately after the Big Bang , when the stars have not yet formed. The second, the Starry Era, includes the present day and all the stars and galaxies we see. During this time, stars form through the collapse of gas clouds . In the following era, the era of degeneration, all stars will be burned out and all objects of stellar mass will be remnants of stars, namely white dwarfs , neutron stars or black holes . According to Adams and Laughlin, in the era of black holes, white dwarfs, neutron stars, and other smaller astronomical objects will disintegrate through proton decay , leaving only black holes. Eventually these will also be gone in the Dark Era and only photons and leptons will exist.

Starry Era

from 10 ⁶ (1 million) years to 10 ¹⁴ (100 trillion) years after the Big Bang

The observable universe is currently 1.38 · 10 ¹⁰ (13.8 billion) years old. Therefore, we are currently in the starry era. Since the first star was formed after the Big Bang, stars have been formed by the collapse of small, dense core regions in large, cold molecular clouds of hydrogen . This first creates a protostar , which is hot and bright due to energy produced by Kelvin-Helmholtz contraction . When this protostar contracts enough, its core will become hot enough for hydrogen fusion and begin its life as a star.

Very low mass stars will use up all of their hydrogen and become white dwarfs of helium. Stars with low to medium mass will eject part of their mass as planetary nebulae and become white dwarfs, stars with larger mass will explode in a type II supernova , creating a neutron star or a black hole. In each of these cases a remnant of the star remains, only part of the star's matter comes back into the interstellar medium. Sooner or later the gas necessary for the formation of stars will run out.

Growing together of the local group

in 10 ¹¹ (100 billion) to 10 ¹² (1 trillion) years

The galaxies of the local group , the galaxy cluster to which the Milky Way and the Andromeda Galaxy belong, are gravitationally bound to one another. The Andromeda Galaxy, currently 2.5 million light years away from our galaxy, is moving towards the galaxy at a speed of around 300 kilometers per second. In about 5 billion years, or 19 billion years after the Big Bang, the Galaxy and Andromeda Galaxy will collide and together form one large galaxy. It is expected that the gravitational effect will cause the Local Group to merge into one giant galaxy in 10 ¹¹ (100 billion) to 10 ¹² (1 billion) years.

Assuming that dark energy leads to an accelerating expansion of the universe, in about 150 billion years all objects outside the local group will be behind the cosmological horizon . This makes it impossible for events in the Local Group to affect other galaxies. Similarly, events after 150 billion years, seen by observers in distant galaxies, will no longer have any effect on the Local Group. An observer in the local group can still see distant galaxies, but what is observed will be exponentially more gravitationally time-shifted and redshifted over time, while the galaxy approaches the cosmological horizon and time seems to stop there for the observer. The observer in the Local Group, however, will not see the distant galaxy disappear behind the cosmological horizon and will never see events that happened 150 billion years later. Therefore, intergalactic transportation and communication will be impossible after 150 billion years.

In 2 · 10 ¹² (2 trillion) years, radiation from all galaxies outside the local supercluster will be so redshifted that even the gamma rays they emit will have wavelengths that are longer than the universe observable at that time . Therefore these galaxies will no longer be recognizable.

Era of degeneration

Formation of stars ends

from 10 ¹⁴ (100 trillion) to 10 ⁴⁰ years

In 100 trillion years, star formation will end, and only star fragments will be left. This time, called the era of degeneration , lasts until the last remnants of the stars crumble. The longest-lived stars in the universe are red dwarfs with the lowest mass (about 0.08 solar masses) that live for about ^10-13 years. Coincidentally, this duration is comparable to the duration of the time it takes for stars to form. When the formation of stars ends and the lightest red dwarfs have used up their fuel, nuclear fusion ends . The low mass red dwarfs will cool down and become dead black dwarfs . The only remaining objects with more than planetary mass will be brown dwarfs with a mass less than 0.08 solar masses and remnants of stars; White dwarfs that arose from stars with a mass of 0.08 to 8 solar masses, as well as neutron stars and black holes that arose from stars with an initial mass of more than 8 solar masses. The largest part of the mass is made up of the white dwarfs, around 90%. Without energy sources, all of these once luminous bodies will cool down and go dark.

The universe will go dark after the last star burns out. Even then, however, there can be newly generated radiation in the universe. One possibility is that two white dwarfs made of carbon and oxygen with a common mass above the Chandrasekhar limit , i.e. about 1.44 solar masses, unite. The resulting object will explode in a Type Ia supernova , interrupting the darkness of the era of degeneration for a few weeks. If the combined mass is below the Chandrasekhar limit, but greater than the minimum mass for nuclear fusion to carbon (about 0.9 solar masses), then another carbon star will be formed with a lifespan of about 10 ⁶ (1 million) years . If two white dwarfs made of helium with a common mass of at least 0.3 solar masses collide, a helium star will be formed with a lifespan of a few hundred million years. If two sufficiently large brown dwarfs collide, a red dwarf is created that can glow for 10 ¹³ (10 trillion) years.

Over time, the objects in a galaxy exchange kinetic energy in a process called dynamic relaxation , so that their velocity distribution approaches the Maxwell-Boltzmann distribution . Dynamic relaxation can occur either through close encounters between two stars or through less strong but more frequent encounters. In the event of a close encounter, two brown dwarfs or remnants of stars meet and the orbits of the objects involved change slightly. After many encounters, heavy objects lose kinetic energy, while light objects gain kinetic energy.

Due to the dynamic relaxation, some objects will gain enough energy to reach the galactic escape speed and leave the galaxy, leaving a smaller, denser galaxy behind. As a result, most of the objects (90% to 99%) leave the galaxy, while a small remainder (1% to 10%) remains and falls into the central supermassive black hole . It is believed that the matter of the star remnants collects in an accretion disk and forms a quasar as long as there is enough matter.

Black Hole Era

in 10 ⁴⁰ to 10 ¹⁰⁰ years

After 10 ⁴⁰ years, black holes will dominate the universe . These slowly evaporate due to Hawking radiation . A black hole with about the mass of the sun exists for about 2 · 10 ⁶⁶ years. Because the life of a black hole is proportional to the cube of its mass, more massive black holes take longer to decay. A supermassive black hole with a mass of 100 billion solar masses evaporates in 2 · 10 ⁹⁹ years.

Hawking radiation corresponds to thermal radiation . For most of the life of the black hole, it has a low temperature, the radiation mainly consists of massless particles such as photons and the hypothetical gravitons . As the mass of the black hole decreases, its temperature increases; when the mass has fallen to 10 ¹⁹ kilograms, it corresponds roughly to that of the sun . The hole then provides a temporary source of light during the general darkness in the black hole era. At the end of their life, black holes not only emit massless particles, but also heavier particles such as electrons , positrons , protons and antiprotons .

Over a period of around ^10–65 years, supposedly rigid objects, such as stones, will be able to rearrange their atoms and molecules via the tunnel effect and behave like a liquid, only more slowly.

Matter breaks down into iron

in 10 ¹⁵⁰⁰ years

In 10 ¹⁵⁰⁰ years, cold fusion could transform light elements into iron -56 through the tunnel effect . Nuclear fission and alpha radiation will also cause heavy elements to break down into iron, with stellar objects ultimately being left behind as cold iron balls, so-called iron stars .

Iron stars collapse into black holes

in to years ${\displaystyle 10^{10^{26}}}$ ${\displaystyle 10^{10^{76}}}$

The tunnel effect will also turn large objects into black holes. That could happen in up to years. The tunnel effect could also cause iron stars to collapse into neutron stars , which should take place in about years. Now the times have also reached astronomical standards. If you wanted to print out the number without a power representation on paper pages in DIN A4 format (1500 characters per page), the stack of pages would extend about 1,000 light years into space beyond the star Rigel . The present-day expansion of the observable universe by orders of magnitude would be too small for such a representation of the number . ${\displaystyle 10^{10^{26}}}$ ${\displaystyle 10^{10^{76}}}$ ${\displaystyle 10^{10^{76}}}$ ${\displaystyle 10^{10^{26}}}$ ${\displaystyle 10^{10^{76}}}$

Supermassive black holes (here an artist's rendering) are all that is left of galaxies after all protons decay, but these giants are not immortal either.

Changes when the nucleons are unstable

Many Big Freeze scenarios assume the existence of proton decay . It is also expected that neutrons bound in the nucleus will also decay with a half-life that is comparable to that of the proton.

In the case of unstable protons, the era of degeneration would be significantly shorter. The specific times are dependent on the underlying half-life of the nucleons. Experiments indicate a lower limit for this half-life of at least 10 ³⁴ years. In the search for a “ Great Unified Theory ”, the proton is assumed to have a half-life of less than 10 ⁴¹ years. In this scenario, a half-life of about 10 ³⁷ years is assumed for the proton . Shorter or longer half-lives speed up or slow down the process.

It is estimated that there are currently ¹⁰⁸⁰ protons in the universe. With the half-life of the proton assumed above, around 1000 half-lives will have passed when the universe is 10 ⁴⁰ years old. This means that the number of protons has been halved 1000 times. Since unbound neutrons decay within minutes, there will be practically no more nucleons at this point. All baryonic matter has turned into photons and leptons . Some models predict the formation of stable positronium with a larger diameter than today's observable universe in 10 ⁸⁵ years, and that it will decay into gamma radiation in 10 ¹⁴¹ years.

There are also predictions about other decay possibilities of the proton, for example about processes such as virtual black holes or other higher-level processes with a half-life of less than 10 ²⁰⁰ years.

Dark era and photon age

from 10 ¹⁰⁰ years

After all black holes have evaporated (and after - in the case of unstable protons - all matter from nucleons has dissolved), the universe will be as good as empty. Photons, neutrinos, electrons and positrons will fly around and hardly meet each other. Dark matter, electrons and positrons then have the highest gravity.

In this era the activity in the universe drops dramatically (compared to the previous eras), there are large time intervals between processes with very small energy conversions. Electrons and positrons flying through space will meet and in some cases form positronium . This is unstable because the components annihilate . At this point in time the universe reaches a very low energy density.

What could happen after that is purely speculative. The Big Rip may well come in the future . Other possibilities are a second inflation or, assuming the vacuum is a false vacuum , the decay of the vacuum to a lower energy state.

At the present low energy densities, quantum events become more important than negligible microscopic events, and consequently the laws of quantum physics dominate.

The universe can potentially avoid heat death through quantum fluctuations that can cause a new big bang in about years. ${\displaystyle 10^{10^{56}}}$

After the recurrence theorem, a spontaneous reduction of entropy could take place over an infinite time , caused by fluctuations (see also fluctuation theorem ).

Timeline

Web links

• Big Rip, Big Crunch and Big Whimper as the possible end of the universe

Individual evidence

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2. ↑ WMAP - Fate of the Universe , WMAP's Universe , NASA . Retrieved July 17, 2008.
3. ^ Sean Carroll : The cosmological constant . In: Living Reviews in Relativity . 4, 2001. Retrieved August 30, 2017.
4. ^ ^{A b c d} Life, the Universe, and Nothing: Life and Death in an Ever-expanding Universe, Lawrence M. Krauss and Glenn D. Starkman, Astrophysical Journal , 531 (March 1, 2000), pp. 22-30. doi: 10.1086 / 308434 . bibcode : 2000ApJ ... 531 ... 22K .
5. ↑ ^{a b c d e f g h} A dying universe: the long-term fate and evolution of astrophysical objects, Fred C. Adams and Gregory Laughlin, Reviews of Modern Physics 69 , # 2 (April 1997), pp. 337-372. bibcode : 1997RvMP ... 69..337A . doi: 10.1103 / RevModPhys.69.337 arxiv : astro-ph / 9701131 .
6. ^ ^{A b c} Adams & Laughlin (1997), §IIE.
7. ^ Adams & Laughlin (1997), §IV.
8. ^ ^{A b} Adams & Laughlin (1997), §VID.
9. ↑ ^{a b} Chapter 7, Calibrating the Cosmos , Frank Levin, New York: Springer, 2006, ISBN 0-387-30778-8 .
10. ↑ Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Data Processing, Sky Maps, and Basic Results , G. Hinshaw et al., The Astrophysical Journal Supplement Series (2008), arxiv : 0803.0732 , bibcode : 2008arXiv0803.0732H .
11. ↑ Planck 2015 results. XIII. Cosmological parameters arxiv : 1502.01589 .
12. ↑ ^{a b c d e f g h} The Five Ages of the Universe , Fred Adams and Greg Laughlin, New York: The Free Press, 1999, ISBN 0-684-85422-8 .
13. ^ Adams & Laughlin (1997), §VA.
14. ↑ Possible Ultimate Fate of the Universe, Jamal N. Islam, Quarterly Journal of the Royal Astronomical Society 18 (March 1977), pp. 3–8, bibcode : 1977QJRAS..18 .... 3I
15. ↑ ^{a b c} Time without end: Physics and biology in an open universe, Freeman J. Dyson, Reviews of Modern Physics 51 (1979), pp. 447-460, doi: 10.1103 / RevModPhys.51.447 .
16. ↑ Planck collaboration: Planck 2013 results. XVI. Cosmological parameters . In: Astronomy & Astrophysics . 2013. arxiv : 1303.5076 . bibcode : 2014A & A ... 571A..16P . doi : 10.1051 / 0004-6361 / 201321591 .
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18. ↑ A. Heger, CL Fryer, SE Woosley, N. Langer, and DH Hartmann: How Massive Single Stars End Their Life . In: Astrophysical Journal 591 , # 1 (2003), pp. 288-300. bibcode : 2003ApJ ... 591..288H
19. ↑ Adams & Laughlin (1997), § III – IV.
20. ↑ ^{a b} Adams & Laughlin (1997), §IIA and Figure 1.
21. ^ ^{A b} Adams & Laughlin (1997), §IIIC.
22. ^ The Future of the Universe , M. Richmond, "Physics 240", Rochester Institute of Technology . Retrieved July 8, 2008.
23. ↑ p. 428, A deep focus on NGC 1883, AL Tadross, Bulletin of the Astronomical Society of India 33 , # 4 (December 2005), pp. 421-431, bibcode : 2005BASI ... 33..421T .
24. ↑ Reading notes , Liliya LR Williams, Astrophysics II: Galactic and Extragalactic Astronomy, University of Minnesota , accessed July 20, 2008.
25. ^ Deep Time , David J. Darling , New York: Delacorte Press, 1989, ISBN 978-0-385-29757-8 .
26. ↑ Particle emission rates from a black hole: Massless particles from an uncharged, nonrotating hole, Don N. Page, Physical Review D 13 (1976), pp. 198-206. doi: 10.1103 / PhysRevD.13.198 .
27. ^ ^{A b c} Adams & Laughlin (1997), §IVA.
28. ↑ G Senjanovic proton decay and grand unification , December 2009
29. ^ Solution, exercise 17 , One Universe: At Home in the Cosmos , Neil de Grasse Tyson, Charles Tsun-Chu Liu, and Robert Irion, Washington, DC: Joseph Henry Press, 2000. ISBN 0-309-06488-0 .
30. ^ Adams & Laughlin (1997), §VD.
31. ^ Adams & Laughlin (1997), §VF3.
32. ^ Adams & Laughlin (1997), §VE.
33. ↑ Carroll, Sean M. and Chen, Jennifer (2004). Spontaneous Inflation and Origin of the Arrow of Time . 
34. ^ Tegmark, Max (2003) Parallel Universes . 
35. ↑ Werlang, T., Ribeiro, GAP and Rigolin, Gustavo (2012) Interplay between quantum phase transitions and the behavior of quantum correlations at finite temperatures . 
36. ^ Xing, Xiu-San (2007) Spontaneous entropy decrease and its statistical formula . 
37. ^ Linde, Andrei (2007) Sinks in the Landscape, Boltzmann Brains, and the Cosmological Constant Problem .