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🔗 Physics 🔗 Lists 🔗 Statistics 🔗 Astronomy 🔗 Time 🔗 Futures studies 🔗 Geology 🔗 Extinction 🔗 Solar System 🔗 Astronomy/Solar System

While the future can never be predicted with absolute certainty, present understanding in various scientific fields allows for the prediction of some far-future events, if only in the broadest outline. These fields include astrophysics, which has revealed how planets and stars form, interact, and die; particle physics, which has revealed how matter behaves at the smallest scales; evolutionary biology, which predicts how life will evolve over time; and plate tectonics, which shows how continents shift over millennia.

All projections of the future of Earth, the Solar System, and the universe must account for the second law of thermodynamics, which states that entropy, or a loss of the energy available to do work, must rise over time. Stars will eventually exhaust their supply of hydrogen fuel and burn out. Close encounters between astronomical objects gravitationally fling planets from their star systems, and star systems from galaxies.

Physicists expect that matter itself will eventually come under the influence of radioactive decay, as even the most stable materials break apart into subatomic particles. Current data suggest that the universe has a flat geometry (or very close to flat), and thus will not collapse in on itself after a finite time, and the infinite future allows for the occurrence of a number of massively improbable events, such as the formation of Boltzmann brains.

The timelines displayed here cover events from the beginning of the 11th millennium to the furthest reaches of future time. A number of alternative future events are listed to account for questions still unresolved, such as whether humans will become extinct, whether protons decay, and whether the Earth survives when the Sun expands to become a red giant.

🔗 Astronomy 🔗 Sweden 🔗 Solar System 🔗 Astronomy/Solar System

The Sweden Solar System is the world's largest permanent scale model of the Solar System. The Sun is represented by the Ericsson Globe in Stockholm, the largest hemispherical building in the world. The inner planets can also be found in Stockholm but the outer planets are situated northward in other cities along the Baltic Sea. The system was started by Nils Brenning and Gösta Gahm and is on the scale of 1:20 million.

🔗 Physics 🔗 Astronomy

The Oh-My-God particle was the highest-energy cosmic ray detected at the time (15 October 1991) by the Fly's Eye detector in Dugway Proving Ground, Utah, US. Its energy was estimated as (3.2±0.9)×10²⁰ eV, or 51 J. This is 20 million times more energetic than the highest energy measured in electromagnetic radiation emitted by an extragalactic object and 10²⁰ (100 quintillion) times the photon energy of visible light, equivalent to a 142-gram (5 oz) baseball travelling at about 26 m/s (94 km/h; 58 mph). Although higher energy cosmic rays have been detected since then, this particle's energy was unexpected, and called into question theories of that era about the origin and propagation of cosmic rays.

Assuming it was a proton, this particle traveled at 99.99999999999999999999951% of the speed of light, its Lorentz factor was 3.2×10¹¹ and its rapidity was 27.1. At this speed, if a photon were travelling with the particle, it would take over 215,000 years for the photon to gain a 1 cm lead as seen in Earth's reference frame.

The energy of this particle is some 40 million times that of the highest energy protons that have been produced in any terrestrial particle accelerator. However, only a small fraction of this energy would be available for an interaction with a proton or neutron on Earth, with most of the energy remaining in the form of kinetic energy of the products of the interaction. The effective energy available for such a collision is √2Emc², where E is the particle's energy and mc² is the mass energy of the proton. For the Oh-My-God particle, this gives 7.5×10¹⁴ eV, roughly 60 times the collision energy of the Large Hadron Collider.

While the particle's energy was higher than anything achieved in terrestrial accelerators, it was still about 40 million times lower than the Planck energy. Particles of such energy would be required in order to explore the Planck scale. A proton with that much energy would travel 1.665×10¹⁵ times closer to the speed of light than the Oh-My-God particle. As viewed from Earth it would take about 3.579×10²⁰ years, or 2.59×10¹⁰ times the current age of the universe, for a photon to gain a 1 cm lead over a Planck energy proton as observed in Earth's reference frame.

Since the first observation, at least 72 similar (energy > 5.7×10¹⁹ eV) events have been recorded, confirming the phenomenon. These ultra-high-energy cosmic ray particles are very rare; the energy of most cosmic ray particles is between 10 MeV and 10 GeV. More recent studies using the Telescope Array have suggested a source for the particles within a 20-degree radius "warm spot" in the direction of the constellation Ursa Major.

🔗 Technology 🔗 History 🔗 Medicine 🔗 Religion 🔗 Biology 🔗 Agriculture 🔗 Economics 🔗 Lists 🔗 Skepticism 🔗 Literature 🔗 Psychology 🔗 Astronomy 🔗 History of Science 🔗 Islam 🔗 Food and drink 🔗 Sexology and sexuality 🔗 Judaism 🔗 Christianity 🔗 Popular Culture 🔗 Sports 🔗 Evolutionary biology

This is a list of common misconceptions. Each entry is formatted as a correction; the misconceptions themselves are implied rather than stated. These entries are meant to be concise, but more detail can be found in the main subject articles.

🔗 Biography 🔗 Women scientists 🔗 Biography/science and academia 🔗 Women's History 🔗 Astronomy 🔗 Smithsonian Institution Archives

Cecilia Helena Payne-Gaposchkin (née Payne; (1900-05-10)May 10, 1900 – (1979-12-07)December 7, 1979) was a British-born American astronomer and astrophysicist who proposed in her 1925 doctoral thesis that stars were composed primarily of hydrogen and helium. Her groundbreaking conclusion was initially rejected because it contradicted the scientific wisdom of the time, which held that there were no significant elemental differences between the Sun and Earth. Independent observations eventually proved she was actually correct

🔗 Telecommunications 🔗 Meteorology 🔗 Astronomy 🔗 Solar System

The solar storm of 1859 (also known as the Carrington Event) was a powerful geomagnetic storm during solar cycle 10 (1855–1867). A solar coronal mass ejection (CME) hit Earth's magnetosphere and induced the largest geomagnetic storm on record, September 1–2, 1859. The associated "white light flare" in the solar photosphere was observed and recorded by British astronomers Richard C. Carrington (1826–1875) and Richard Hodgson (1804–1872). The storm caused strong auroral displays and wrought havoc with telegraph systems. The now-standard unique IAU identifier for this flare is SOL1859-09-01.

A solar storm of this magnitude occurring today would cause widespread electrical disruptions, blackouts and damage due to extended outages of the electrical grid. The solar storm of 2012 was of similar magnitude, but it passed Earth's orbit without striking the planet, missing by nine days.

🔗 History 🔗 Physics 🔗 Telecommunications 🔗 Skepticism 🔗 Astronomy 🔗 History of Science 🔗 Physics/History 🔗 Paranormal

The Wow! signal was a strong narrowband radio signal received on August 15, 1977, by Ohio State University's Big Ear radio telescope in the United States, then used to support the search for extraterrestrial intelligence. The signal appeared to come from the direction of the constellation Sagittarius and bore the expected hallmarks of extraterrestrial origin.

Astronomer Jerry R. Ehman discovered the anomaly a few days later while reviewing the recorded data. He was so impressed by the result that he circled the reading on the computer printout, "6EQUJ5", and wrote the comment "Wow!" on its side, leading to the event's widely used name.

The entire signal sequence lasted for the full 72-second window during which Big Ear was able to observe it, but has not been detected since, despite several subsequent attempts by Ehman and others. Many hypotheses have been advanced on the origin of the emission, including natural and human-made sources, but none of them adequately explains the signal.

Although the Wow! signal had no detectable modulation—a technique used to transmit information over radio waves—it remains the strongest candidate for an alien radio transmission ever detected.

🔗 Physics 🔗 Astronomy

Entropic gravity, also known as emergent gravity, is a theory in modern physics that describes gravity as an entropic force—a force with macro-scale homogeneity but which is subject to quantum-level disorder—and not a fundamental interaction. The theory, based on string theory, black hole physics, and quantum information theory, describes gravity as an emergent phenomenon that springs from the quantum entanglement of small bits of spacetime information. As such, entropic gravity is said to abide by the second law of thermodynamics under which the entropy of a physical system tends to increase over time.

At its simplest, the theory holds that when gravity becomes vanishingly weak—levels seen only at interstellar distances—it diverges from its classically understood nature and its strength begins to decay linearly with distance from a mass.

Entropic gravity provides the underlying framework to explain Modified Newtonian Dynamics, or MOND, which holds that at a gravitational acceleration threshold of approximately 1.2×10⁻¹⁰ m/s², gravitational strength begins to vary inversely (linearly) with distance from a mass rather than the normal inverse-square law of the distance. This is an exceedingly low threshold, measuring only 12 trillionths gravity's strength at earth's surface; an object dropped from a height of one meter would fall for 36 hours were earth's gravity this weak. It is also 3,000 times less than exists at the point where Voyager 1 crossed our solar system's heliopause and entered interstellar space.

The theory claims to be consistent with both the macro-level observations of Newtonian gravity as well as Einstein's theory of general relativity and its gravitational distortion of spacetime. Importantly, the theory also explains (without invoking the existence of dark matter and its accompanying math featuring new free parameters that are tweaked to obtain the desired outcome) why galactic rotation curves differ from the profile expected with visible matter.

The theory of entropic gravity posits that what has been interpreted as unobserved dark matter is the product of quantum effects that can be regarded as a form of positive dark energy that lifts the vacuum energy of space from its ground state value. A central tenet of the theory is that the positive dark energy leads to a thermal-volume law contribution to entropy that overtakes the area law of anti-de Sitter space precisely at the cosmological horizon.

The theory has been controversial within the physics community but has sparked research and experiments to test its validity.

🔗 Technology 🔗 Environment 🔗 Science Fiction 🔗 Astronomy 🔗 Transhumanism 🔗 Futures studies 🔗 Energy

The Kardashev scale is a method of measuring a civilization's level of technological advancement based on the amount of energy they are able to use. The measure was proposed by Soviet astronomer Nikolai Kardashev in 1964. The scale has three designated categories:

• A Type I civilization, also called a planetary civilization—can use and store all of the energy available on its planet.
• A Type II civilization, also called a stellar civilization—can use and control energy at the scale of its stellar system.
• A Type III civilization, also called a galactic civilization—can control energy at the scale of its entire host galaxy.

🔗 Physics 🔗 China 🔗 Astronomy 🔗 History of Science 🔗 Astronomy/Astronomical objects 🔗 Arab world

SN 1006 was a supernova that is likely the brightest observed stellar event in recorded history, reaching an estimated −7.5 visual magnitude, and exceeding roughly sixteen times the brightness of Venus. Appearing between April 30 and May 1, 1006 AD in the constellation of Lupus, this "guest star" was described by observers across the modern day countries of China, Japan, Iraq, Egypt, and the continent of Europe, and possibly recorded in North American petroglyphs. Some reports state it was clearly visible in the daytime. Modern astronomers now consider its distance from Earth to be about 7,200 light-years.