Universe: Recent featured articles

Cosmogony, or cosmogeny, is any theory concerning the coming into existence or origin of the universe, or about how reality came to be. The word comes from the Greek "cosmos, the world", and the root of "to be born, come about". In the specialized context of space science and astronomy, the term refers to theories of creation of (and study of) the Solar System. More about the Cosmogony origin of the universe.

The Galactic Center is the rotational center of the Milky Way galaxy. It is located at a distance of 7.62±0.32 kpc (~25,000±1,000 ly) from the Earth in the direction of the constellations Sagittarius, Ophiuchus, and Scorpius where the Milky Way appears brightest. It is believed that there is a supermassive black hole at the Galactic Center of the Milky Way. More about the Galatic Center.

In our universe, The Large Magellanic Cloud (LMC) is a nearby irregular galaxy, once thought to be a satellite of our own. At a distance of slightly less than 50 kiloparsecs (˜160,000 light-years), the LMC is the third closest galaxy to the Milky Way, with the Sagittarius Dwarf Spheroidal (~ 16 kiloparsecs) and Canis Major Dwarf Galaxy (~ 12.9 kiloparsecs) lying closer to the center of the Milky Way. More about the Large Magellanic Cloud.

In the universe, a supernova remnant (SNR) is the structure resulting from the gigantic explosion of a star in a supernova. The supernova remnant is bounded by an expanding shock wave.

There are two possible routes to a supernova: either a massive star may run out of fuel, ceasing to generate fusion energy in its core, and collapsing inward under the force of its own gravity to form a neutron star or a black hole; or a white dwarf star may accumulate (accrete) material from a companion star until it reaches a critical mass and undergoes a thermonuclear explosion. More about the Supernova remnant.

The Copenhagen interpretation is an interpretation of quantum mechanics. A key feature of quantum mechanics is that the state of every particle is described by a wavefunction, which is a mathematical representation used to calculate the probability for it to be found in a location or a state of motion. According to this interpretation, the act of measurement causes the calculated set of probabilities to "collapse" to the value defined by the measurement. This feature of the mathematical representations is known as wavefunction collapse. More about the Copenhagen interpretation.

Schrödinger's cat is a thought experiment, often described as a paradox. It illustrates what he saw as the problem of the Copenhagen interpretation of quantum mechanics applied to everyday objects. According to Schrödinger, the Copenhagen interpretation implies that the cat remains both alive and dead (to the universe outside the box) until the box is opened. More about the Schrödinger's cat.

The Chaotic Inflation theory is a variety of the inflationary universe model, which is itself an outgrowth (or extension) of the Big Bang theory. Chaotic Inflation, proposed by physicist Andrei Linde, models our universe as one of many that grew as part of a multiverse owing to a vacuum that had not decayed to its ground state. In this theory, the peaks in the evolution of a scalar field (determining the energy of the vacuum) correspond to regions of rapid inflation which dominate, creating "bubble universes," making the structure of space fractal on the very largest scales, likely at scales larger than the observable universe. More about the Chaotic Inflation theory.

The Cosmic Background Explorer (COBE), also referred to as Explorer 66, was a satellite dedicated to cosmology. Its goals were to investigate the cosmic microwave background radiation (CMB) of the universe and provide measurements that would help shape our understanding of the cosmos.

This work provided evidence that supported the big-bang theory of the universe: that the CMB was a near-perfect black-body spectrum. More about the COBE

The Columbia Hills are a range of low hills inside Gusev crater on Mars. They were observed by the Mars Exploration Rover Spirit when it landed within the crater in 2004. They were promptly given an unofficial name by NASA since they were the most striking nearby feature on the surface. The surface of Mars is thought to be primarily composed of basalt, based upon the Martian meteorite collection and orbital observations. There is some evidence that a portion of the Martian surface might be more silica-rich than typical basalt, perhaps similar to andesitic stones on Earth More about the Columbia Hills Mars

Eagle is a small impact crater in which the Mars Exploration Rover Opportunity found itself after landing on Mars in 2004.

The crater is located on Meridiani Planum. Scientists are delighted that the rover landed there, as the crater contains rocky outcroppings that helped prove that Meridiani was once an ocean floor. Read more about: Eagle crater Mars.

The steady state theory of Bondi, Gold, was inspired by the circular plot of the film Dead of Night which they had watched together. Theoretical calculations showed that a static universe was impossible under general relativity and observations by Edwin Hubble had shown that the universe was expanding. The steady state theory asserts that although the universe is expanding, it nevertheless does not change its look over time (the perfect cosmological principle); it has no beginning and no end. More about the Steady State Theory of the Universe.

In particle physics, the strong interaction, or strong force, or color force, holds quarks and gluons together to form protons, neutrons and other particles. The strong interaction is one of the four fundamental interactions, along with gravitation, the electromagnetic force and the weak interaction. The word strong is used since the strong interaction is the "strongest" of the four fundamental forces; its typical field strength is 100 times the strength of the electromagnetic force, some 10¹³ times as great as that of the weak force, and about 10³⁸ times that of gravitation. Read more about: Strong force.

The four inner or terrestrial planets are characterised by their dense, rocky composition, few or no moons, and lack of ring systems. They are composed largely of minerals with high melting points such as silicates to form the planets' solid crusts and semi-liquid mantles, and metals such as iron and nickel, which form their cores.. More about the Inner planets.

The four outer planets, or gas giants, (sometimes called Jovian planets) are so large they collectively make up 99 percent of the mass known to orbit the Sun. Jupiter and Saturn are true giants, at 318 and 95 Earth masses, respectively, and composed largely of hydrogen and helium. Uranus and Neptune are both substantially smaller, being only 14 and 17 Earth masses, respectively.. Read more about: Outer planets.

Lasers are thought of as emitting light with a narrow wavelength spectrum ("monochromatic" light). This is not true of all lasers, however: some emit light with a broad spectrum, while others emit light at multiple distinct wavelengths simultaneously. The coherence of typical laser emission is distinctive. Most other light sources emit incoherent light, which has a phase that varies randomly with time and position. More about the Lasers.

The goddess Isis (the mother of Horus) was the first daughter of Geb, god of the Earth, and Nut, the goddess of the Overarching Sky, and was born on the fourth intercalary day. At some time Isis absorbed some characteristics of Hathor a powerful deity. He represented the pharaohs and provided them with protection. In later myths about Isis, she had a brother, Osiris, who became her husband, and she then was said to have conceived Horus. Isis was instrumental in the resurrection of Osiris when he was murdered by Seth. Her magical skills restored his body to life after she gathered the body parts that had been strewn about the earth by Seth. This myth became very important in later Egyptian religious beliefs. Read more about: Isis Goddess.

Night sky is a commonly used term most often employed to refer to the sky as it is seen at night. The term is usually associated with astronomy, with reference to views of heavenly bodies such as stars, the Moon and planets that become visible on a clear night after the Sun has set. Read more about: Night sky.

Optics usually describes the behaviour of visible, ultraviolet, and infrared light; however because light is an electromagnetic wave, similar phenomena occur in X-rays, microwaves, radio waves, and other forms of electromagnetic radiation and analogous phenomena occur with charged particle beams. Since the discovery by James Clerk Maxwell that light is electromagnetic radiation, optics has largely been regarded in theoretical physics as a sub-field of electromagnetism. Some optical phenomena depend on the quantum nature of light relating some areas of optics to quantum mechanics. In practice, the vast majority of optical phenomena can be accounted for using the classical electromagnetic description of light, as described by Maxwell's equations, resorting to phenomenological rules (e.g. Beer's Law, constitutive equations) to describe the interaction of light with matter. Read more about: Optics.

Fermi's interaction is an old explanation of the weak force, proposed by Enrico Fermi. Four fermions directly interact with one another. For example, this interaction is directly able to split a neutron (or two down-quarks and an up-quark) to an electron, antineutrino and a proton (or two up-quarks and a down-quark).. More about the Fermi's interaction.

The Hertzsprung-Russell diagram can be used to define different types of stars in the universe and to match theoretical predictions of stellar evolution using computer models with observations of actual stars. It is then necessary to convert either the calculated quantities to observables, or the other way around, thus introducing an extra uncertainty. More about the The Hertzsprung-Russell diagram.

In most modern usages of spectrum there is a unifying theme between extremes at either end. Some older usages of the word did not have a unifying theme, but they led to modern ones through a sequence of events set out below. Modern usages in mathematics did evolve from a unifying theme, but this may be difficult to recognize: Read more about: Spectrum.

Hypergiants are very luminous stars, up to millions of solar luminosities, and have temperatures varying widely between 3,500 K and 35,000 K. Almost all hypergiants exhibit variations in luminosity over time due to instabilities within their interiors. Because of their high masses, the lifetime of a hypergiant is very short in astronomical timescales, only a few million years compared to around 10 billion years for stars like the Sun. Because of this, hypergiants are extremely rare and only a handful are known today. More about the Hypergiant star.

The Extreme ultraviolet Imaging Telescope (EIT) is an instrument on the SOHO spacecraft used to obtain high-resolution images of the solar corona in the ultraviolet range. The EIT instrument is sensitive to light of four different wavelengths: 17.1, 19.5, 28.4, and 30.4 nm, corresponding to light produced by highly ionized iron (XI)/(X), (XII), (XV), and helium (II), respectively. EIT is built as a single telescope with a quadrant structure to the entrance mirrors: each quadrant reflects a different color of EUV light: Read more about: Ultraviolet Imaging Telescope.

According to the electroweak theory, at very high energies, the universe has four massless gauge boson fields similar to the photon and a complex scalar Higgs field doublet. The gauge bosons are associated with a SU(2) ×U(1) gauge symmetry. However, at low energies, one of the Higgs fields acquires a vacuum expectation value and the gauge symmetry is spontaneously broken down to the U(1) symmetry of electromagnetism.

The weak interaction affects all left-handed leptons and quarks. It is the only force affecting neutrinos (except for gravitation, which is negligible on laboratory scales). The weak interaction is unique in a number of respects: Read more about: Weak force.

The Standard Model of particle physics is a theory of three of the four known fundamental interactions and the elementary particles that take part in these interactions. These particles make up all visible matter in the universe. The standard model is a gauge theory of the electroweak and strong interactions with the gauge group SU(3)×SU(2)×U(1). . More about the The Standard Model of particle physics.

In this physical cosmology context, the limitation of the definition of "universe" that it has only one set of "physical laws and constants that govern them," is expanded to include multiple sets of physical laws and constants, each expressed as a wholly or partially separate universe. The term is used in quantum mechanics to differentiate the concept of a limited number of universes from all existent universes. Read more about: Omniverse.

ome theories beyond the Standard Model include a hypothetical fifth force, and the search for such a force is an ongoing line of experimental research in physics. In supersymmetric theories, there are particles that acquire their masses only through supersymmetry breaking effects and these particles, known as moduli can mediate new forces. Another reason to look for new forces is the recent discovery that the expansion of the universe is accelerating, giving rise to a need to explain a nonzero cosmological constant, and possibly to other modifications of general relativity. More about the Fundamental interaction.

The future of an expanding universe is bleak. If a cosmological constant accelerates the expansion of the universe, clusters of galaxies will rapidly be driven away from each other, leaving observers in different clusters unable to either reach each other or sense each other's presence in any way. Stars are expected to form normally, but eventually the supply of gas needed for star formation will be exhausted. Once the last star has exhausted its fuel, stars will then cease to shine. The stellar remnants left behind are expected to disappear as their protons decay, leaving behind only black holes which themselves eventually disappear as they emit Hawking radiation. More about the Future expanding universe.

The addition of gravity to the story leads to a considerably richer variety of phenomena. The key insight is that a false vacuum with positive potential energy density is a de Sitter vacuum, in which the potential energy acts as a cosmological constant and the Universe is undergoing the exponential expansion of de Sitter space. This leads to a number of interesting effects, first studied by Coleman and de Luccia. Read more about: False vacuum.

Nothing or nothingness is defined as: The state of being nothing; no thing; not anything; zero. However, from a philosophical point of view, nothing could be farther from the truth. How could the universe come from nothingness? Could nothingness actually exist? Or has ther always been a something. This page examines the fundamentals of all concepts; both philosophy and logic.

Did God create the universe? Or did the universe create God? These are just some of the intriguing questions posed.

Maybe a nothing could be physics neuterd. And if there was a nothingness before the universe existed, what caused the nothing to become something? More about the Nothing.

An Epoch in astronomy is a point of reference. To help us understand the universe better, the epoch is determined when an observation is made, or when a prediction is calculated for a specific event, such as orbital elements of a celestial body.

Due to precession and proper motion, star positions become less useful as their equinox and epoch get older. After a while, it is easier to switch to a newer epoch and equinox than keep applying corrections to data from the older epoch and equinox.

The epoch itself addresses changes in the position of the celestial body. Read more about: Epoch in Astronomy.

Galaxy Messier 49 (also known as M 49 or NGC 4472) is an elliptical / lenticular galaxy about 49 million light-years away in the constellation Virgo. The galaxy was discovered by Charles Messier in 1771.

Messier 49 is the brightest member of the Virgo Cluster. The galaxy is located at the center of one of the subclusters within the Virgo Cluster. Read more about: Galaxy Messier 49.

The first stars in the universe are thought to have been considerably brighter and more massive than the stars in the modern universe. These stars were part of the theorized population III of stars. Their existence is necessary to explain observations of elements other than hydrogen and helium in quasars.

Most type II supernova progenitors are thought to be red supergiants. However, the progenitor for Supernova 1987A was a blue supergiant. It is believed that it was a red supergiant before losing its outer layers to its strong stellar wind. More about the Supergiant stars.

Could one single theory really unlock all the secrets of the universe? It might just be possible!

Grand Unification, grand unified theory, or GUT refers to any of several very similar unified field theories or models in physics that predicts that at extremely high energies (above 10¹⁴ GeV), the electromagnetic, weak nuclear, and strong nuclear forces are fused into a single unified field. More about the Grand Unified Theory

The European Organization for Nuclear Research (French: Organisation Européenne pour la Recherche Nucléaire), known as CERN, is the world's largest particle physics laboratory, situated in the northwest suburbs of Geneva on the Franco-Swiss border, established in 1954. The organization has twenty European member states, and is currently the workplace of approximately 2,600 full-time employees, as well as some 7,931 scientists and engineers (representing 580 universities and research facilities and 80 nationalities). Read more about the CERN.

An Equinox occurs twice a year, when the tilt of the Earth's axis is inclined neither away from nor towards the Sun, the Sun being vertically above a point on the Equator. The term equinox can also be used in a broader sense, meaning the date when such a passage happens. The name "equinox" is derived from the Latin aequus (equal) and nox (night). More about the Equinox

The horizon problem results from the premise that information cannot travel faster than light, and hence two regions of space which are separated by a greater distance than the speed of light multiplied by the age of the universe cannot be in Causal contact. The observed isotropy of the Cosmic microwave background (CMB) is problematic in this regard, because the horizon size at that time corresponds to a size that is about 2 degrees on the sky. If the universe has had the same expansion history since the Planck epoch, there is no mechanism to cause these regions to have the same temperature.

About the same time space shuttle Atlantis’ landing was waved off today due to continued rainy weather in Florida, the White House announced that former shuttle commander Charles Bolden Jr. will be nominated as NASA’s next administrator. President Obama also chose Lori Garver to be Bolden’s deputy administrator. Obama said, “These talented individuals will help put NASA on course to boldly push the boundaries of science, aeronautics and space exploration in the 21st century and ensure the long-term vibrancy of America’s space program.”

A now-you-see-it, now-you don’t accretion disk (white and blue in the artist’s rendering at left) has tipped astronomers to the birth of a superfast, “millisecond” pulsar that was happening right before their eyes — er, their radio telescopes.

The new finding confirms the long-suspected evolutionary connection between a neutron star and a millisecond pulsar: they are two life stages of the same object.

Anne Archibald, of McGill University in Montreal, Canada and her colleagues announced their discovery in the May 21 online issue of the journal Science.

Not surprisingly, former astronaut Jeff Hoffman has been watching the current Hubble servicing mission with interest. After all, he was a member of the first repair crew that visited the telescope in December 1993, part of the team which essentially rescued the Hubble program from what could have been a disaster. But, now Hoffman is impressed with this current crew and what they’ve accomplished, saying they are part of a “brotherhood of Hubble warriors.”

And Hoffman is feeling a little nostalgic, too

In a convergence of science fiction and current technology, the new Star Trek movie has been “beamed up” to the International Space Station so the three occupants can watch it while orbiting 220 miles above Earth. Paramount sent a copy of the movie to NASA’s Mission Control, which then uplinked the movie to the International Space Station. The crew plans to watch the film on a laptop computer in the Unity module.

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Radio Telescopes looking for signals from distant civilizations might be an effort in futility, according to scientists who met at Harvard University recently. The dominant view of astronomers at a symposium on the future of human life in the Universe seems to be that if other life is out there, it likely is dominated by microbes or other nonspeaking creatures.

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In 1971 physicist Stephen Hawking suggested that there might be “mini” black holes all around us that were created by the Big Bang. The violence of the rapid expansion following the beginning of the Universe could have squeezed concentrations of matter to form miniscule black holes, so small they can’t even be seen in a regular microscope. But what if these mini black holes were everywhere, and in fact, what if they make up the fabric of the universe? A new paper from two researchers in California proposes this idea.

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The checkout and calibration phase for the Kepler spacecraft has been completed, and now the telescope will begin one of the longest and most important stare-downs ever attempted. Kepler will spend the next three-and-a-half years staring at more than 100,000 stars searching for telltale signs of planets. Kepler should have the ability to find planets as small as Earth that orbit sun-like stars at distances where temperatures are right for possible lakes and oceans. “Now the fun begins,” said William Borucki, Kepler science principal investigator for the mission. “We are all really excited to start sorting through the data and discovering the planets.”

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For 15 years, the Hubble Space Telescope’s Wide Field and Planetary Camera 2 (WFPC2) has been churning out amazing and breathtaking images of our universe. But during the upcoming HST servicing mission, a new and improved version of Hubble’s main camera will replace the optical workhorse that has provided so many memorable and awe-inspiring images. WFPC2 was brought up on orbit to Hubble in December of 1993 to replace the original camera, outfitted with special optics to overcome the spherical aberration in Hubble’s main mirror. To honor the WFPC2, here are a few of the most memorable discoveries the camera has made Galleries of the universe.

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As the race ramps up to find Earth-like planets around other stars, lasers are a viable option.

That according to researchers at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, who have created an “astro-comb,” a sort of calibration tool based on wavelengths of light, to pick up minute variations in a star’s motion caused by orbiting planets.

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Neutron stars are dying stars that are seemingly ‘off the charts’ in almost every category. They are small and extremely dense; about 20 km in diameter with masses of about 1.4 times that of our Sun, meaning that on Earth, one teaspoon of a neutron star would weigh about 100 million tons. They also rotate exceeding fast, about 700 times per second. And according to a new study, neutron stars have another almost super-hero like quality: the outer surface of these collapsed stars is likely to be 10 billion times stronger than steel or any other of Earth’s strongest alloys.

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The name “dark energy” is just a placeholder for the force — whatever it is — that is causing the Universe to expand. But astronomers are perhaps getting closer to understanding this force. New observations of several Cepheid variable stars by the Hubble Space Telescope has refined the measurement of the Universe’s present expansion rate to a precision where the error is smaller than five percent. The new value for the expansion rate, known as the Hubble constant, or H0 (after Edwin Hubble who first measured the expansion of the universe nearly a century ago), is 74.2 kilometers per second per megaparsec (error margin of ± 3.6). The results agree closely with an earlier measurement gleaned from Hubble of 72 ± 8 km/sec/megaparsec, but are now more than twice as precise.

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Caltech has announced it will begin decommissioning the Caltech Submillimeter Observatory (CSO) in Hawaii starting in 2016.

Caltech says the 23-year-old telescope is being replaced by the next generation of radio telescope, the Cornell Caltech Atacama Telescope (CCAT), to be located in Chile.

“The timing of this works very nicely,” says Tom Phillips, director of the CSO and Altair Professor of Physics in Caltech’s Division of Physics, Mathematics and Astronomy. “The international community of astronomers that rely on CSO will have a seamless transition as CCAT comes online just as CSO is decommissioned.”

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People looking for new ways to explain climate change on Earth have sometimes turned to cosmic rays, showers of atomic nuclei that emanate from the Sun and other sources in the cosmos.

But new research, in press in the journal Geophysical Research Letters, says cosmic rays are puny compared to other climatic influences, including greenhouse gases — and not likely to impact Earth’s climate much.

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Fireworks in the universe? Astronomers are comparing “starbursts” from a galaxy that is in the throes of star formation to a Fourth of July fireworks display. And three particular galaxies are like my children’s favorite part of a fireworks display: the grand finale. These bursts occur at a fast and furious pace, lighting up a region for a short time before winking out. But that’s only part of the story. Archived data from the Hubble Space Telescope are showing that starbursts — intense regions of star formation — sweep across the whole galaxy and last 100 times longer than astronomers thought. The longer duration may affect how dwarf galaxies change over time, and therefore may shed light on galaxy evolution.

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