STEREO

STEREO (Solar Terrestrial Relations Observatory) is a solar observation mission.[1] Two nearly identical spacecraft were launched in 2006 into orbits around the Sun that cause them to respectively pull farther ahead of and fall gradually behind the Earth. This enables stereoscopic imaging of the Sun and solar phenomena, such as coronal mass ejections.

STEREO
Deployment of STEREO spacecraft panels (crop)
Illustration of a STEREO spacecraft during solar array deployment
Mission typeSolar observation
OperatorNASA
COSPAR IDSTEREO A: 2006-047A
STEREO B: 2006-047B
SATCAT no.STEREO A: 29510
STEREO B: 29511
Websitehttp://stereo.gsfc.nasa.gov/
http://stereo.jhuapl.edu/
Mission durationPlanned: 2 years
Elapsed: 12 years, 2 months, 22 days
Spacecraft properties
ManufacturerJohns Hopkins University Applied Physics Laboratory
Launch mass619 kg (1,364 lb)
Dry mass547 kg (1,206 lb)
Dimensions1.14 × 2.03 × 6.47 m
3.75 × 6.67 × 21.24 ft
Power475 W
Start of mission
Launch dateOctober 26, 2006, 00:52 UTC
RocketDelta II 7925-10L
Launch siteCape Canaveral SLC-17B
ContractorUnited Launch Alliance
Orbital parameters
Reference systemHeliocentric
PeriodSTEREO A: 346 days
STEREO B: 388 days
Instruments
SECCHISun Earth Connection Coronal and Heliospheric Investigation
IMPACTIn-situ Measurements of Particles and CME Transients
PLASTICPlasma and Suprathermal Ion Composition
S/WAVESSTEREO/WAVES

Mission profile

This introductory video demonstrates STEREO's locations and shows a simultaneous image of the entire Sun.
Animation of STEREO trajectory
Animation of STEREO's trajectory from 27 October 2006 to 1 October 2014
  STEREO A ·   STEREO B ·   Earth

The two STEREO spacecraft were launched at 00:52 UTC on October 26, 2006, from Launch Pad 17B at the Cape Canaveral Air Force Station in Florida on a Delta II 7925-10L launcher into highly elliptical geocentric orbits. The apogee reached the Moon's orbit. On December 15, 2006, on the fifth orbit, the pair swung by the Moon for a gravity assist. Because the two spacecraft were in slightly different orbits, the "ahead" (A) spacecraft was ejected to a heliocentric orbit inside Earth's orbit while the "behind" (B) spacecraft remained temporarily in a high Earth orbit. The B spacecraft encountered the Moon again on the same orbital revolution on January 21, 2007, being ejected from Earth orbit in the opposite direction from spacecraft A. Spacecraft B entered a heliocentric orbit outside the Earth's orbit. Spacecraft A will take 347 days to complete one revolution of the Sun and Spacecraft B will take 387 days. The A spacecraft/Sun/Earth angle will increase at 21.650 degree/year. The B spacecraft/Sun/Earth angle will change −21.999 degrees per year. Given that the length of Earth's orbit is around 940 million kilometres, both craft have an average speed, in a rotating geocentric frame of reference in which the sun is always in the same direction, of about 1.8 km/s, but the speed varies considerably depending on how close they are to their respective aphelion or perihelion (as well as on the position of Earth). Their current locations are shown here.

Over time, the STEREO spacecraft will continue to separate from each other at a combined rate of approximately 44 degrees per year. There are no final positions for the spacecraft. They achieved 90 degrees separation on January 24, 2009, a condition known as quadrature. This is of interest because the mass ejections seen from the side on the limb by one spacecraft can potentially be observed by the in situ particle experiments of the other spacecraft. As they passed through Earth's Lagrangian points L4 and L5, in late 2009, they searched for Lagrangian (trojan) asteroids. On February 6, 2011, the two spacecraft were exactly 180 degrees apart from each other, allowing the entire Sun to be seen at once for the first time.[2]

Even as the angle increases, the addition of an Earth-based view, e.g., from the Solar Dynamics Observatory, will still provide full-Sun observations for several years. In 2015, contact was lost for several months when the STEREO spacecraft passed behind the Sun. They will then start to approach Earth again, with closest approach sometime in 2023. They will not be recaptured into Earth orbit.[3]

Loss of contact with STEREO-B

On October 1, 2014, contact was lost with STEREO-B during a planned reset to test the craft's automation, in anticipation of the aforementioned solar "conjunction" period. The team originally thought the spacecraft had begun to spin, decreasing the amount of power that could be generated by the solar panels.[3] NASA used its Deep Space Network, first weekly and later monthly, to try to re-establish communications.[3] After a silence of 22 months, contact was regained at 22:27 UTC on August 21, 2016, when the Deep Space Network established a lock on STEREO-B for 2.4 hours.[4][5][6]

Later analysis of the received telemetry concluded that the spacecraft was in an uncontrolled spin of about three degrees per second; this is too rapid to be immediately corrected using its reaction wheels, which would become oversaturated.[5] Engineers will work to develop software to fix the spacecraft, but once its computer is powered on there will only be about two minutes to upload the fix before STEREO-B enters failure mode again.[7] Further, while the spacecraft was power positive at the time of contact, its orientation will drift and power levels will fall.[5]

As of 11 October 2016, recovery attempts have been reduced until the spacecraft returns to a favorable orbit. Six attempts at communication between September 27 and October 9 failed, and a carrier wave has not been detected since September 23.[5] The Hubble Space Telescope will be used in 2019 to image STEREO-B in order for engineers to determine its anomalous orientation in space which will help lay the groundwork for reestablishing contact. STEREO-B and Earth will overlap in 2023.

NASA terminated periodic recovery operations effective October 17, 2018.[8]

Mission benefits

The principal benefit of the mission is stereoscopic images of the Sun. In other words, because the satellites are at different points along the Earth's orbit, but distant from the Earth, they can photograph parts of the Sun that are not visible from the Earth. This permits NASA scientists to directly monitor the far side of the Sun, instead of inferring the activity on the far side from data that can be gleaned from Earth's view of the Sun. The STEREO satellites principally monitor the far side for coronal mass ejections — massive bursts of solar wind, solar plasma, and magnetic fields that are sometimes ejected into space.[9]

Since the radiation from coronal mass ejections, or CMEs, can disrupt Earth's communications, airlines, power grids, and satellites, more accurate forecasting of CMEs has the potential to provide greater warning to operators of these services.[9] Before STEREO, the detection of the sunspots that are associated with CMEs on the far side of the Sun was only possible using helioseismology, which only provides low-resolution maps of the activity on the far side of the Sun. Since the Sun rotates every 25 days, detail on the far side was invisible to Earth for days at a time before STEREO. The period that the Sun's far side was previously invisible was a principal reason for the STEREO mission.[10]

STEREO program scientist Madhulika Guhathakurta expects "great advances" in theoretical solar physics and space weather forecasting with the advent of constant 360-degree views of the Sun.[11] STEREO's observations are already being incorporated into forecasts of solar activity for airlines, power companies, satellite operators, and others.[12]

STEREO has also been used to discover 122 eclipsing binaries and study hundreds more variable stars.[13] STEREO can look at the same star for up to 20 days.[13]

On July 23, 2012, STEREO-A was in the path of the Solar storm of 2012 which was similar in strength to the Carrington Event.[14] Its instrumentation was able to collect and relay a significant amount of data about the event. STEREO-A was not harmed by the solar storm.

Science instrumentation

Stereo mission
Instrument locations on STEREO

Each of the spacecraft carries cameras, particle experiments and radio detectors in four instrument packages:

  • Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) has five cameras: an extreme ultraviolet imager (EUVI) and two white-light coronagraphs (COR1 and COR2). These three telescopes are collectively known as the Sun Centered Instrument Package or SCIP, and image the solar disk and the inner and outer corona. Two additional telescopes, heliospheric imagers (called the HI1 and HI2) image the space between Sun and Earth. The purpose of SECCHI is to study the 3-D evolution of coronal mass ejections through their full journey from the Sun's surface through the corona and interplanetary medium to their impact at Earth.[15][16]
  • In-situ Measurements of Particles and CME Transients (IMPACT) will study energetic particles, the three-dimensional distribution of solar wind electrons and interplanetary magnetic field.[15][17]
  • PLAsma and SupraThermal Ion Composition (PLASTIC) will study the plasma characteristics of protons, alpha particles and heavy ions.[15]
  • STEREO/WAVES (SWAVES) is a radio burst tracker that will study radio disturbances traveling from the Sun to the orbit of Earth.[15]

Spacecraft subsystems

Each STEREO spacecraft had a dry mass of 547 kg (1,206 lb) and a launch mass of 619 kg (1,364 lb). In their stowed configuration, each had a length, width and height of 2.0 × 1.2 × 1.1 m (6.67 × 4.00 × 3.75 ft). Upon solar array deployment, its width increased to 6.5 m (21.24 ft).[18][19] With all of its instrument booms and antennae deployed, its dimensions are 7.5 × 8.7 × 5.9 m (24.5 × 28.6 × 19.2 ft).[20] The solar panels can produce an average of 596 watts of power, and the spacecraft consumes an average of 475 watts.[18][19]

The STEREO spacecraft are 3-axis stabilized, and each has a primary and backup miniature inertial measurement unit (MIMU) provided by Honeywell.[21] These measure changes to a spacecraft's attitude, and each MIMU contains three ring laser gyroscopes to detect angular changes. Additional attitude information is provided by the star tracker and the SECCHI Guide Telescope.[22]

STEREO's onboard computer systems are based on the Integrated Electronics Module (IEM), a device that combines core avionics in a single box. Each single-string spacecraft carries two CPUs, one for command-and-data handling and one for guidance and control. Both are radiation hardened 25 megahertz IBM RAD6000 processors, based on POWER1 CPUs (predecessor of the PowerPC chip found in older Macintoshes). The computers, slow by current personal computer standards, are typical for the radiation requirements needed on the STEREO mission.

STEREO also carries Actel FPGAs that use triple modular redundancy for radiation hardening. The FPGAs hold the P24 MISC and CPU24 soft microprocessors.[23]

For data storage, each spacecraft carries a solid state recorder able to store up to one gigabyte each. Its main processor collects and stores on the recorder images and other data from STEREO's instruments, which can then be sent back to Earth. The spacecraft have an X-band downlink capacity of between 427 and 750 kbps.[18][19]

Gallery

The two STEREO observatories

STEREO probes stacked at Astrotech in Florida
August 11, 2006

STEREO launch Delta7925-10L 261006

Launch of the STEREO probes on a Delta II rocket
October 26, 2006

Sun STEREO 4dec2006 lrg

One of the first images of the Sun taken by STEREO
December 4, 2006

A lunar transit of the Sun captured during calibration of STEREO B's ultraviolet imaging cameras. The Moon appears much smaller than it does from Earth, because the spacecraft-Moon separation was several times greater than the Earth-Moon distance.
February 25, 2007

174719main LEFTREDSouthPole304

The Sun's South Pole. Material can be seen erupting off the Sun in the lower right side of the image.
March 2007

Sun 3D anaglyph STEREO crop bright

A three-dimensional anaglyph taken by STEREO
March 2007
3d glasses red cyan.svg 3D red cyan glasses are recommended to view this image correctly.

BLUE STEREO 3D Time for Space Wiggle

A three-dimensional time-for-space wiggle image taken by STEREO
March 2007

Jup20081123 000901 s4h1A 1024

Jupiter as seen by STEREO-A HI1
November 23, 2008

Far side of the Sun 3D STEREO crop

Nearly the entire far side of the Sun
February 2, 2011

STEREO EUV Feb10 rotating

Nearly the entire surface of the Sun, taken in extreme ultraviolet at 19.5 nm with white lines showing solar coordinates (0 degrees is directly towards Earth)
February 10, 2011

A full day of Sun data from the STEREO satellites
February 13–14, 2011

For STEREO's 10th anniversary, Deputy Project Scientist Terry Kucera gives an overview of the mission's top 5 success stories.

See also

References

  1. ^ "NASA Launch Schedule". NASA. September 20, 2006. Retrieved September 20, 2006.
  2. ^ Zell, Holly, ed. (February 6, 2011). "First Ever STEREO Images of the Entire Sun". NASA.
  3. ^ a b c Sarah, Frazier (December 11, 2015). "Saving STEREO-B: The 189-million-mile Road to Recovery". NASA.
  4. ^ Fox, Karen C. (August 22, 2016). "NASA Reestablishes Contact with STEREO Mission". NASA. Retrieved August 22, 2016.
  5. ^ a b c d "What's New". STEREO Science Center. NASA. October 11, 2016. Archived from the original on October 23, 2016.
  6. ^ Geldzahler, Barry; et al. (2017). A Phased Array of Widely Separated Antennas for Space Communication and Planetary Radar (PDF). Advanced Maui Optical and Space Surveillance Technologies Conference. September 19-22, 2017. Wailea, Maui, Hawaii. pp. 13–14. Bibcode:2017amos.confE..82G.
  7. ^ Mosher, Dave (August 23, 2016). "NASA may have less than 2 minutes to rescue its long-lost spacecraft". Business Insider. Retrieved August 24, 2016.
  8. ^ "STEREO SCIENCE CENTER - Current Status".
  9. ^ a b "Sun bares all for twin space probes". CBC News. February 7, 2011. Retrieved February 8, 2011.
  10. ^ Lemonick, Michael (February 6, 2011). "NASA Images the Entire Sun, Far Side and All". Time. Retrieved February 8, 2011.
  11. ^ Winter, Michael (February 7, 2011). "Sun shines in twin probes' first 360-degree images". USA Today. Retrieved February 8, 2011.
  12. ^ "Stereo satellites move either side of Sun". BBC News. February 6, 2011. Retrieved February 8, 2011.
  13. ^ a b "STEREO turns its steady gaze on variable stars". Astronomy. Royal Astronomical Society. April 19, 2011. Retrieved April 19, 2011.
  14. ^ "Near Miss: The Solar Superstorm of July 2012". NASA. July 23, 2014. Retrieved July 24, 2014.
  15. ^ a b c d "STEREO Spacecraft & Instruments". NASA. March 8, 2006. Retrieved May 30, 2006.
  16. ^ Howard, R. A.; Moses, J. D.; Socker, D. G.; Dere, K. P.; Cook, J. W. (June 2002). "Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI)" (Submitted manuscript). Advances in Space Research. 29 (12): 2017–2026. Bibcode:2002AdSpR..29.2017H. doi:10.1016/S0273-1177(02)00147-3.
  17. ^ Luhmann, J. G.; Curtis, D. W.; Lin, R. P.; Larson, D.; Schroeder, P.; et al. (2005). "IMPACT: Science goals and firsts with STEREO". Advances in Space Research. 36 (8): 1534–1543. Bibcode:2005AdSpR..36.1534L. doi:10.1016/j.asr.2005.03.033.
  18. ^ a b c Gurman, Joseph B., ed. (2007). "STEREO Spacecraft". NASA/Goddard Space Flight Center. Retrieved August 22, 2016.
  19. ^ a b c "STEREO - Solar TErrestrial RElations Observatory" (PDF). NASA. 2005. NP-2005-8-712-GSFC. Retrieved August 22, 2016.
  20. ^ Beisser, Kerri (ed.). "STEREO - Characteristics". Applied Physics Laboratory. Retrieved August 22, 2016.
  21. ^ "Honeywell To Provide Miniature Inertial Measurement Units For STEREO Spacecraft". Honeywell International. Archived from the original on November 25, 2005. Retrieved October 25, 2006.
  22. ^ Driesman, Andrew; Hynes, Shane; Cancro, George (April 2008). "The STEREO Observatory". Space Science Reviews. 136 (1): 17–44. Bibcode:2008SSRv..136...17D. doi:10.1007/s11214-007-9286-z.
  23. ^ Mewaldt, R. A.; Cohen, C. M. S.; Cook, W. R.; Cummings, A. C.; Davis, A. J.; et al. (April 2008). "The Low-Energy Telescope (LET) and SEP Central Electronics for the STEREO Mission" (PDF). Space Science Reviews. 136 (1): 285–362. Bibcode:2008SSRv..136..285M. CiteSeerX 10.1.1.459.4982. doi:10.1007/s11214-007-9288-x.

External links

8-track tape

The 8-track tape (formally Stereo 8; commonly known as the eight-track cartridge, eight-track tape, or simply eight-track) is a magnetic tape sound-recording technology that was popular in the United States from 1964 to 1988, when the Compact Cassette format took over. The format is regarded as an obsolete technology, and was relatively unknown outside the United States, the United Kingdom, Canada, New Zealand, Australia, Germany and Japan.Stereo 8 was created in 1964 by a consortium led by Bill Lear of Lear Jet Corporation, along with Ampex, Ford Motor Company, General Motors, Motorola, and RCA Victor Records (RCA - Radio Corporation of America). It was a further development of the similar Stereo-Pak four-track cartridge introduced by Earl "Madman" Muntz (marketing and television set dealer), which was adapted by Muntz from the Fidelipac cartridge developed by George Eash. A later quadraphonic (four-channel sound as opposed to earlier more widely used stereo/two channel sound) version of the format was announced by RCA in April 1970 and first known as Quad-8, then later changed to just Q8.

Audio mixing

Audio mixing is the process by which multiple sounds are combined into one or more channels. In the process, a source's volume level, frequency content, dynamics, and panoramic position are manipulated and or enhanced. This practical, aesthetic, or otherwise creative treatment is done in order to produce a finished version that is appealing to listeners.

Audio mixing is practiced for music, film, television and live sound. The process is generally carried out by a mixing engineer operating a mixing console or digital audio workstation.

Audio mixing (recorded music)

In sound recording and reproduction, audio mixing is the process of combining multitrack recordings into a final mono, stereo or surround sound product. These tracks that are blended together are done so by using various processes such as equalization and compression. Audio mixing techniques and approaches can vary widely, and due to the skill-level or intent of the mixer, can greatly affect the qualities of the sound recording.Audio mixing techniques largely depend on music genres and the quality of sound recordings involved. The process is generally carried out by a mixing engineer, though sometimes the record producer or recording artist may assist. After mixing, a mastering engineer prepares the final product for production.

Audio mixing may be performed on a mixing console or digital audio workstation.

Bose Corporation

Bose Corporation is a privately held American corporation, based in Framingham, Massachusetts, that designs, develops and sells audio equipment. Founded in 1964 by Amar Bose, the company sells its products throughout the world. According to the company annual report in the 2017 financial year, Bose received revenue of US$3.8 billion and employed more than 8,000 people.

Bose is best known for its home audio systems and speakers, noise cancelling headphones, professional audio systems and automobile sound systems. The company has also conducted research into suspension technologies for cars and heavy-duty trucks and into the subject of cold fusion. Bose has a reputation for being particularly protective of its patents, trademarks, and brands.

A majority of Bose Corporation's non-voting shares were given by Amar Bose in 2011 to his alma mater and former employer, the Massachusetts Institute of Technology. They receive cash dividends, but are prohibited from selling the shares and are unable to participate in the management and governance of the company.

Dolby Digital

Dolby Digital is the name for audio compression technologies developed by Dolby Laboratories. Originally named Dolby Stereo Digital until 1994, except for Dolby TrueHD, the audio compression is lossy. The first use of Dolby Digital was to provide digital sound in cinemas from 35mm film prints; today, it is now also used for other applications such as TV broadcast, radio broadcast via satellite, digital video streaming, DVDs, Blu-ray discs and game consoles.

FM broadcasting

FM broadcasting is a method of radio broadcasting using frequency modulation (FM) technology. Invented in 1933 by American engineer Edwin Armstrong, wide-band FM is used worldwide to provide high-fidelity sound over broadcast radio. FM broadcasting is capable of better sound quality than AM broadcasting (under normal listening conditions), the chief competing radio broadcasting technology, so it is used for most music broadcasts. Theoretically wideband AM can offer equally good sound quality, provided the reception conditions are ideal. FM radio stations use the VHF frequencies. The term "FM band" describes the frequency band in a given country which is dedicated to FM broadcasting.

Game Boy

The Game Boy is an 8-bit handheld game console which was developed and manufactured by Nintendo and first released on April 21, 1989 (1989-04-21), in North America on July 31, 1989 (1989-07-31), and in Europe on September 28, 1990 (1990-09-28). It is the first handheld console in the Game Boy line and was created and published by Satoru Okada and Nintendo Research & Development 1. This same team, led by Gunpei Yokoi at the time, is credited with designing the Game & Watch series as well as several popular games for the Nintendo Entertainment System. Redesigned versions were released in 1996 and 1998 in the form of Game Boy Pocket and Game Boy Light (Japan only), respectively.

The Game Boy is Nintendo's first handheld game console and it combined features from both the Nintendo Entertainment System and Game & Watch. It was sold either as a standalone unit or bundled with the puzzle game Tetris.

During its early lifetime, the Game Boy mainly competed with Sega's Game Gear, Atari's Lynx, and NEC's TurboExpress. The Game Boy outsold its rivals and became a significant success. The Game Boy and its successor, the Game Boy Color, have sold over 118 million units worldwide. Upon the Game Boy's release in the United States, its entire shipment of one million units was sold within a few weeks. Production of the Game Boy and Game Boy Color were discontinued in the early 2000s, being replaced by the subsequent Game Boy Advance, released in 2001.

List of Kannada-language television channels

Below is the list of current satellite television channels in Kannada language, a Dravidian language widely spoken in the South Indian state of Karnataka. Apart from those in the below list, many other Kannada channels exist that are limited to certain cities or districts, run by local cable TV operators.

Monaural

Monaural or monophonic sound reproduction (often shortened to mono) is sound intended to be heard as if it were emanating from one position. This contrasts with stereophonic sound or stereo, which uses two separate audio channels to reproduce sound from two microphones on the right and left side, which is reproduced with two separate loudspeakers to give a sense of the direction of sound sources. In mono, only one loudspeaker is necessary, but, when played through multiple loudspeakers or headphones, identical signals are fed to each speaker, resulting in the perception of one-channel sound "imaging" in one sonic space between the speakers (provided that the speakers are set up in a proper symmetrical critical-listening placement). Monaural recordings, like stereo ones, typically use multiple microphones fed into multiple channels on a recording console, but each channel is "panned" to the center. In the final stage, the various center-panned signal paths are usually mixed down to two identical tracks, which, because they are identical, are perceived upon playback as representing a single unified signal at a single place in the soundstage. In some cases, multitrack sources are mixed to a one-track tape, thus becoming one signal. In the mastering stage, particularly in the days of mono records, the one- or two-track mono master tape was then transferred to a one-track lathe intended to be used in the pressing of a monophonic record. Today, however, monaural recordings are usually mastered to be played on stereo and multi-track formats, yet retain their center-panned mono soundstage characteristics.

Monaural sound has largely been replaced by stereo sound in most entertainment applications, but remains the standard for radiotelephone communications, telephone networks, and audio induction loops for use with hearing aids. FM radio stations broadcast in stereo, while most AM radio stations broadcast in mono. (Although an AM stereo broadcast standard exists, few AM stations are equipped to use it.) A few FM stations—notably talk-radio stations—choose to broadcast in monaural because of the slight advantage in signal strength and bandwidth the standard affords over a stereophonic signal of the same power.

Phone connector (audio)

A phone connector, also known as phone jack, audio jack, headphone jack or jack plug, is a family of electrical connectors typically used for analog audio signals.

The phone connector was invented for use in telephone switchboards in the 19th century and is still widely used.

The phone connector is cylindrical in shape, with a grooved tip to retain it. In its original audio configuration, it typically has two, three, four and, occasionally, five contacts. Three-contact versions are known as TRS connectors, where T stands for "tip", R stands for "ring" and S stands for "sleeve". Ring contacts are typically the same diameter as the sleeve, the long shank. Similarly, two-, four- and five- contact versions are called TS, TRRS and TRRRS connectors respectively. The outside diameter of the "sleeve" conductor is 6.35 millimetres (1⁄4 inch). The "mini" connector has a diameter of 3.5 mm (0.14 in) and the "sub-mini" connector has a diameter of 2.5 mm (0.098 in).

Quadraphonic sound

Quadraphonic (or Quadrophonic and sometimes Quadrasonic) sound – equivalent to what is now called 4.0 surround sound – uses four channels in which speakers are positioned at the four corners of the listening space, reproducing signals that are (wholly or in part) independent of one another. Quadraphonic audio was the earliest consumer product in surround sound and thousands of quadraphonic recordings were made during the 1970s.

It was a commercial failure due to many technical problems and format incompatibilities. Quadraphonic audio formats were more expensive to produce than standard two-channel stereo. Playback required additional speakers and specially designed decoders and amplifiers.

RCA Records

RCA Records (formerly legally traded as the RCA Records Label) is an American record label owned by Sony Music, a subsidiary of Sony Corporation of America. It is one of Sony Music's four flagship labels, alongside its former long-time rival Columbia Records, Arista Records, and Epic Records. The label has released multiple genres of music, including pop, classical, rock, hip hop, electronic, R&B, blues, jazz, and country. Its name is derived from the initials of its defunct parent company, the Radio Corporation of America (RCA). It was fully acquired by Bertelsmann in 1986, making it a part of Bertelsmann Music Group (BMG); however, RCA Records became a part of Sony BMG Music Entertainment, a merger between BMG and Sony Music, in 2004, and was acquired by the latter in 2008, after the dissolution of Sony BMG and the restructuring of Sony Music. It is the second oldest record label in American history, after sister label Columbia Records.

Artists currently signed to RCA Records include Britney Spears,

Shakira, SZA, Christina Aguilera, Miley Cyrus, Justin Timberlake, Alicia Keys, Backstreet Boys, Usher, Charlie Wilson, Enrique Iglesias, Foo Fighters, Jake Bugg, Kings of Leon, Kesha, Khalid, D'Angelo, Pentatonix, Pink, Craig David, Buddy Guy, Walk the Moon, Pitbull, Brockhampton and Zayn.

Stereochemistry

Stereochemistry, a subdiscipline of chemistry, involves the study of the relative spatial arrangement of atoms that form the structure of molecules and their manipulation. The study of stereochemistry focuses on stereoisomers, which by definition have the same molecular formula and sequence of bonded atoms (constitution), but differ in the three-dimensional orientations of their atoms in space. For this reason, it is also known as 3D chemistry—the prefix "stereo-" means "three-dimensionality".An important branch of stereochemistry is the study of chiral molecules. Stereochemistry spans the entire spectrum of organic, inorganic, biological, physical and especially supramolecular chemistry. Stereochemistry includes methods for determining and describing these relationships; the effect on the physical or biological properties these relationships impart upon the molecules in question, and the manner in which these relationships influence the reactivity of the molecules in question (dynamic stereochemistry).

Stereoisomerism

In stereochemistry, stereoisomers are isomeric molecules that have the same molecular formula and sequence of bonded atoms (constitution), but differ in the three-dimensional orientations of their atoms in space. This contrasts with structural isomers, which share the same molecular formula, but the bond connections or their order differs. By definition, molecules that are stereoisomers of each other represent the same structural isomer.

Stereophonic sound

Stereophonic sound or, more commonly, stereo, is a method of sound reproduction that creates an illusion of multi-directional audible perspective. This is usually achieved by using two or more independent audio channels through a configuration of two or more loudspeakers (or stereo headphones) in such a way as to create the impression of sound heard from various directions, as in natural hearing. Thus the term "stereophonic" applies to so-called "quadraphonic" and "surround-sound" systems as well as the more common two-channel, two-speaker systems. It is often contrasted with monophonic, or "mono" sound, where audio is heard as coming from one position, often ahead in the sound field (analogous to a visual field). In the 2000s, stereo sound is common in entertainment systems such as broadcast radio, TV, recorded music, internet, computer audio, and cinema.

Stereopsis

Stereopsis (from the Greek στερεο- stereo- meaning "solid", and ὄψις opsis, "appearance, sight") is a term that is most often used to refer to the perception of depth and 3-dimensional structure obtained on the basis of visual information deriving from two eyes by individuals with normally developed binocular vision. Because the eyes of humans, and many animals, are located at different lateral positions on the head, binocular vision results in two slightly different images projected to the retinas of the eyes. The differences are mainly in the relative horizontal position of objects in the two images. These positional differences are referred to as horizontal disparities or, more generally, binocular disparities. Disparities are processed in the visual cortex of the brain to yield depth perception. While binocular disparities are naturally present when viewing a real 3-dimensional scene with two eyes, they can also be simulated by artificially presenting two different images separately to each eye using a method called stereoscopy. The perception of depth in such cases is also referred to as "stereoscopic depth".The perception of depth and 3-dimensional structure is, however, possible with information visible from one eye alone, such as differences in object size and motion parallax (differences in the image of an object over time with observer movement), though the impression of depth in these cases is often not as vivid as that obtained from binocular disparities.

Therefore, the term stereopsis (or stereoscopic depth) can also refer specifically to the unique impression of depth associated with binocular vision; what is colloquially referred to as seeing "in 3D".

It has been suggested that the impression of "real" separation in depth is linked to the precision with which depth is derived, and that a conscious awareness of this precision – perceived as an impression of interactability and realness – may help guide the planning of motor action.

Stereoscopy

Stereoscopy (also called stereoscopics, or stereo imaging) is a technique for creating or enhancing the illusion of depth in an image by means of stereopsis for binocular vision. The word stereoscopy derives from Greek, Modern στερεός (stereos), meaning 'firm, solid', and σκοπέω (skopeō), meaning 'to look, to see'. Any stereoscopic image is called a stereogram. Originally, stereogram referred to a pair of stereo images which could be viewed using a stereoscope.

Most stereoscopic methods present two offset images separately to the left and right eye of the viewer. These two-dimensional images are then combined in the brain to give the perception of 3D depth. This technique is distinguished from 3D displays that display an image in three full dimensions, allowing the observer to increase information about the 3-dimensional objects being displayed by head and eye movements.

Stone Temple Pilots

Stone Temple Pilots (often abbreviated as STP) are an American rock band from San Diego, California, that originally consisted of Scott Weiland (lead vocals), brothers Dean DeLeo (guitar) and Robert DeLeo (bass, backing vocals), and Eric Kretz (drums). From the band's formation in 1989, its line-up remained unchanged until the firing of Weiland in February 2013. Linkin Park vocalist Chester Bennington joined the band in May 2013. In November 2015, Bennington left the band to focus solely on Linkin Park. On December 3, 2015, Weiland was found dead on his tour bus before a performance with his band The Wildabouts. In 2016, the band launched an online audition for a new lead vocalist. On July 20, 2017, Bennington was found dead at his home. His death was ruled as suicide by hanging. On November 14, 2017, Jeff Gutt became the new singer of the band.

After forming in 1989 under the name Mighty Joe Young, the band signed with Atlantic Records and changed its name to Stone Temple Pilots. The band's debut album, Core (1992), was a commercial success, and they went on to become one of the most commercially successful bands of the 1990s, selling more than 18 million albums in the United States and 35 million worldwide. The band released four more studio albums: Purple (1994), Tiny Music... Songs from the Vatican Gift Shop (1996), No. 4 (1999), and Shangri-La Dee Da (2001), before separating in 2002, after which the band members partook in various projects (most notably Velvet Revolver and Army of Anyone). The band eventually reconvened in 2008 for a reunion tour, released a new self-titled album in 2010, and actively toured until Chester Bennington's departure. The band's only material with Bennington was the EP High Rise in 2013. The band released its seventh studio album, also titled Stone Temple Pilots, on March 16, 2018.While initially rising to fame as part of the grunge movement of the early 1990s, further releases from the band expressed a variety of influences, including psychedelic rock, bossa nova and classic rock. The band's evolution throughout the 1990s and early 2000s involved periods of commercial highs and lows, brought about in part by Weiland's well-publicized struggles with drug addiction.

The Apples in Stereo

The Apples in Stereo, styled as The Apples in stereo, are an American rock band associated with Elephant Six Collective, a group of bands also including Neutral Milk Hotel, The Olivia Tremor Control, Elf Power, Of Montreal, and Circulatory System. The band is largely a product of lead vocalist/guitarist/producer Robert Schneider, who writes the majority of the band's music and lyrics. Currently, The Apples in Stereo also includes longstanding members John Hill (rhythm guitar) and Eric Allen (bass), as well as more recent members John Dufilho (drums), John Ferguson (keyboards), and Ben Phelan (keyboards/guitar/trumpet).

The band's sound draws comparisons to the psychedelic rock of The Beatles and The Beach Boys during the 1960s, as well as to bands such as Electric Light Orchestra and Pavement, and also draws from lo-fi, garage rock, new wave, R&B, bubblegum pop, power pop, punk, electro-pop and experimental music.

The band is well known for their appearance in a The Powerpuff Girls music video performing the song "Signal in the Sky (Let's Go)". It aired immediately after the show's seventh episode of season 4, "Superfriends", which was based on the song's lyrics. Moreover, the band has appeared widely on television and film, including performances on The Colbert Report, Late Night with Conan O'Brien and Last Call with Carson Daly, guest hosting on MTV, song placements in numerous television shows, commercials and motion pictures, the performance of the single "Energy" by the contestants on American Idol, and a song recorded for children's show Yo Gabba Gabba.

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