Don't miss the piglix.com special BONUS offer during our Beta-test period. The next 100 new Registered Users (from a unique IP address), to post at least five (5) piglix, will receive 1,000 extra sign-up points (eventually exchangeable for crypto-currency)!

* * * * *    Free piglix.com Launch Promotions    * * * * *

  • Free Ads! if you are a small business with annual revenues of less than $1M - piglix.com will place your ads free of charge for up to one year! ... read more

  • $2,000 in free prizes! piglix.com is giving away ten (10) Meccano Erector sets, retail at $200 each, that build a motorized Ferris Wheel (or one of 22 other models) ... see details

Mathe Forum Schule und Studenten
0 votes
This piglix contains articles or sub-piglix about Physical universe
piglix posted in Celestial objects by Galactic Guru
   
0 votes

Energy


This piglix contains articles or sub-piglix about Energy


...

Wikipedia
0 votes

Universe


imageUniverse

The Universe is all of time and space and its contents. It includes planets, moons, minor planets, stars, galaxies, the contents of intergalactic space, and all matter and energy. The size of the entire Universe is unknown.

The earliest scientific models of the Universe were developed by ancient Greek and Indian philosophers and were geocentric, placing the Earth at the center of the Universe. Over the centuries, more precise astronomical observations led Nicolaus Copernicus (1473–1543) to develop the heliocentric model with the Sun at the center of the Solar System. In developing the law of universal gravitation, Sir Isaac Newton (NS: 1643–1727) built upon Copernicus's work as well as observations by Tycho Brahe (1546–1601) and Johannes Kepler's (1571–1630) laws of planetary motion.

Further observational improvements led to the realization that our Solar System is located in the Milky Way galaxy, which is one of many galaxies in the Universe. It is assumed that galaxies are distributed uniformly and the same in all directions, meaning that the Universe has neither an edge nor a center. Discoveries in the early 20th century have suggested that the Universe had a beginning and that it is expanding at an increasing rate. The majority of mass in the Universe appears to exist in an unknown form called dark matter.



...

Wikipedia
0 votes

Space


This piglix contains articles or sub-piglix about Space


...

Wikipedia
0 votes

Nature


This piglix contains articles or sub-piglix about Nature


...

Wikipedia
0 votes

Matter


This piglix contains articles or sub-piglix about Matter


...

Wikipedia
0 votes

Age of the universe


In physical cosmology, the age of the universe is the time elapsed since the Big Bang. The current measurement of the age of the universe is 13.799±0.021 billion years ((13.799±0.021)×109 years) within the Lambda-CDM concordance model. The uncertainty of 21 million years has been obtained by the agreement of a number of scientific research projects, such as microwave background radiation measurements by the Planck satellite, the Wilkinson Microwave Anisotropy Probe and other probes. Measurements of the cosmic background radiation give the cooling time of the universe since the Big Bang, and measurements of the expansion rate of the universe can be used to calculate its approximate age by extrapolating backwards in time.

The Lambda-CDM concordance model describes the evolution of the universe from a very uniform, hot, dense primordial state to its present state over a span of about 13.8 billion years of cosmological time. This model is well understood theoretically and strongly supported by recent high-precision astronomical observations such as WMAP. In contrast, theories of the origin of the primordial state remain very speculative. If one extrapolates the Lambda-CDM model backward from the earliest well-understood state, it quickly (within a small fraction of a second) reaches a singularity called the "Big Bang singularity". This singularity is not understood as having a physical significance in the usual sense, but it is convenient to quote times measured "since the Big Bang" even though they do not correspond to a physically measurable time. For example, "10−6 seconds after the Big Bang" is a well-defined era in the universe's evolution. If one referred to the same era as "13.8 billion years minus 10−6 seconds ago", the precision of the meaning would be lost because the minuscule latter time interval is swamped by uncertainty in the former.



...

Wikipedia
0 votes

Accelerating expansion of the universe


The accelerating expansion of the universe is the observation that the universe appears to be expanding at an increasing rate. In formal terms, this means that the cosmic scale factor a(t) has a positive second derivative, so that the velocity at which a distant galaxy is receding from the observer is continuously increasing with time.

The expansion of the universe has been accelerating since the universe entered its dark-energy-dominated era, at redshift z ≈ 0.4 (roughly 5 billion years ago). Within the framework of general relativity, an accelerating expansion can be accounted for by a positive value of the cosmological constant Λ, equivalent to the presence of a positive vacuum energy, dubbed "dark energy". While there are alternative possible explanations, the description assuming dark energy (positive Λ) is used in the current standard model of cosmology, known as ΛCDM (lambda cold dark matter).

The accelerated expansion was discovered in 1998, when two independent projects, the Supernova Cosmology Project and the High-Z Supernova Search Team simultaneously obtained results suggesting an acceleration in the expansion of the universe by using distant type Ia supernovae as standard candles. The discovery was unexpected, cosmologists at the time expecting a deceleration in the expansion of the universe, and amounts to the realization that the universe is currently in a "dark-energy-dominated era". Three members of these two groups have subsequently been awarded Nobel Prizes for their discovery. Confirmatory evidence has been found in baryon acoustic oscillations and other new results about the clustering of galaxies.



...

Wikipedia
0 votes

Big Bang


The Big Bang theory is the prevailing cosmological model for the universe from the earliest known periods through its subsequent large-scale evolution. The model accounts for the fact that the universe expanded from a very high density and high temperature state, and offers a comprehensive explanation for a broad range of phenomena, including the abundance of light elements, the cosmic microwave background, large scale structure and Hubble's Law. If the known laws of physics are extrapolated to the highest density regime, the result is a singularity which is typically associated with the Big Bang. Detailed measurements of the expansion rate of the universe place this moment at approximately 13.8 billion years ago, which is thus considered the age of the universe. After the initial expansion, the universe cooled sufficiently to allow the formation of subatomic particles, and later simple atoms. Giant clouds of these primordial elements later coalesced through gravity in halos of dark matter, eventually forming the stars and galaxies visible today.

Since Georges Lemaître first noted in 1927 that an expanding universe could be traced back in time to an originating single point, scientists have built on his idea of cosmic expansion. While the scientific community was once divided between supporters of two different expanding universe theories, the Big Bang and the Steady State theory, empirical evidence provides strong support for the former. In 1929, from analysis of galactic redshifts, Edwin Hubble concluded that galaxies are drifting apart; this is important observational evidence consistent with the hypothesis of an expanding universe. In 1965 the cosmic microwave background radiation was discovered, which was crucial evidence in favor of the Big Bang model, since that theory predicted the existence of background radiation throughout the universe before it was discovered. More recently, measurements of the redshifts of supernovae indicate that the expansion of the universe is accelerating, an observation attributed to dark energy's existence. The known physical laws of nature can be used to calculate the characteristics of the universe in detail back in time to an initial state of extreme density and temperature.



...

Wikipedia
0 votes

Clockwork universe


In the history of science, the clockwork universe compares the universe to a mechanical clock. It continues ticking along, as a perfect machine, with its gears governed by the laws of physics, making every aspect of the machine predictable.

This idea was very popular among deists during the Enlightenment, when Isaac Newton derived his laws of motion, and showed that alongside the law of universal gravitation, they could explain the behaviour of both terrestrial objects and the solar system.

A similar concept goes back, to John of Sacrobosco's early 13th-century introduction to astronomy: On the Sphere of the World. In this widely popular medieval text, Sacrobosco spoke of the universe as the machina mundi, the machine of the world, suggesting that the reported eclipse of the Sun at the crucifixion of Jesus was a disturbance of the order of that machine.

Responding to Gottfried Leibniz, a prominent supporter of the theory, in the Leibniz–Clarke correspondence, Samuel Clarke wrote:

In 2009 artist Tim Wetherell created a large wall piece for Questacon (The National Science and Technology centre in Canberra, Australia) representing the concept of the clockwork universe. This steel artwork contains moving gears, a working clock, and a movie of the lunar terminator.



...

Wikipedia
0 votes

Cosmic latte


imageCosmic latte

Cosmic Latte is a name assigned to the average color of the universe, given by a team of astronomers from Johns Hopkins University. In 2001, Karl Glazebrook and Ivan Baldry determined that the color of the universe was a greenish white, but they soon corrected their analysis in a 2002 paper, in which they reported that their survey of the color of all light in the universe added up to a slightly beigeish white. The survey included more than 200,000 galaxies, and measured the spectral range of the light from a large volume of the universe. The hexadecimal RGB value for Cosmic Latte is #FFF8E7.

The finding of the "color of the universe" was not the focus of the study, which was examining spectral analysis of different galaxies to study star formation. Like Fraunhofer lines, the dark lines displayed in the study's spectral ranges display older and younger stars and allow Glazebrook and Baldry to determine the age of different galaxies and star systems. What the study revealed is that the overwhelming majority of stars formed about 5 billion years ago. Because these stars would have been "brighter" in the past, the color of the universe changes over time shifting from blue to red as more blue stars change to yellow and eventually red giants.

Glazebrook's and Baldry's work was funded by the David and Lucile Packard Foundation.

As light from distant galaxies reaches the Earth, the average "color of the universe" (as seen from Earth) marginally increases towards pure white, due to the light coming from the stars when they were much younger and bluer.

The color was displayed in a Washington Post article. Glazebrook jokingly said that he was looking for suggestions for a name for the new color. Several people who read the article sent in suggestions. These were the results of a vote of the scientists involved based on the new color.



...

Wikipedia

1,000 EXTRA POINTS!

Don't forget! that as one of our early users, you are eligible to receive the 1,000 point bonus as soon as you have created five (5) acceptable piglix.

...