Terrestrial Time is a theoretical uniform time scale, defined to provide continuity with the former Ephemeris Time ( ET ).

ET was an independent time-variable, proposed ( and its adoption agreed ) in the period 1948 – 52 with the intent of forming a gravitationally uniform time scale as far as was feasible at that time, and depending for its definition on Simon Newcomb's Tables of the Sun ( 1895 ), interpreted in a new way to accommodate certain observed discrepancies.

Newcomb's tables formed the basis of all astronomical ephemerides of the Sun from 1900 through 1983: they were originally expressed ( and published ) in terms of Greenwich Mean Time and the mean solar day, but later, in respect of the period 1960 – 1983, they were treated as expressed in terms of ET, in accordance with the adopted ET proposal of 1948 – 52.

The term ephemeris time ( often abbreviated ET ) can in principle refer to time in connection with any astronomical ephemeris.

Close equality between the ET second with the later SI second ( as defined with reference to the cesium atomic clock ) has been verified to within 1 part in 10 < sup > 10 </ sup >.

These measurements can be considered as secondary realizations ( in a metrological sense ) of the primary definition of ET in terms of the solar motion, after a calibration of the mean motion of the Moon with respect to the mean motion of the Sun.

Such secondary realizations were used and described as ' ET ', with an awareness that the time scales based on the atomic clocks were not identical to that defined by the primary ephemeris time standard, but rather, an improvement over it on account of their closer approximation to uniformity.

The atomic clocks gave rise to the atomic time scale, and to what was first called Terrestrial Dynamical Time and is now Terrestrial Time, defined to provide continuity with ET.

The availability of atomic clocks, together with the increasing accuracy of astronomical observations ( which meant that relativistic corrections were at least in the foreseeable future no longer going to be small enough to be neglected ), led to the eventual replacement of the ephemeris time standard by more refined time scales including terrestrial time and barycentric dynamical time, to which ET can be seen as an approximation.

In addition to these motor problems, a variety of non-motor features have recently been linked with ET.

Recent studies have demonstrated that late-onset ET ( onset > age 65 ) may be associated with an increased risk of developing dementia.

ET is one of the most common neurological diseases, with a prevalence of approximately 4 % in persons age 40 and older and considerably higher among persons in their 60s, 70s, 80s, and 90s.

In disabling cases, ET can interfere with a person's ability to perform tasks of daily living, including feeding, dressing, and activities of personal hygiene.

People with ET can sometimes have problems with word finding and can't articulate themselves effectively even with preparation.

A person with ET may become shy, withdrawn, pessimistic, anxious and also have difficulties concentrating.

It is common for those with ET to be embarrassed by the condition even though it is out of their control.

Recent postmortem studies have demonstrated the presence of degenerative changes in the ET brain, with these changes including Purkinje cell axonal swellings and Purkinje cell loss in the majority of cases and brainstem Lewy bodies in the remainder.

ET does sometimes occur in combination with other neurological disorders such as dystonia.

In addition, there may be a link between ET and Parkinson's disease, with one study showing ET patients having an approximately 4 times greater likelihood of developing Parkinson's disease.

Minor cases of ET can be treated with physical therapy and development of the muscles in the sections of the body that are severe in their shaking.

ET, and rebroadcasts TMC's " Splatterday " block from the previous week on Friday nights at 10 p. m.

ET, with rebroadcasts through 6 a. m. local time, depending on the station ( though most CBS stations end Up to the Minute at 4: 00 a. m. with the CBS Morning News airing after it ).

The so-called Stabilized Temperature Platform Furnace ( STPF ) concept, proposed by Walter Slavin, based on research of Boris L ’ vov, makes ET AAS essentially free from interference.

ET, in turn, can now be seen ( in light of modern results ) as close to the average mean solar time between 1750 and 1890 ( centered on 1820 ), because that was the period during which the observations on which Newcomb's tables were based were performed.

The atomic clocks offered a further secondary realization of ET, on a quasi-real time basis that soon proved to be more useful than the primary ET standard: not only more convenient, but also more precisely uniform than the primary standard itself.

However, emerging research based on brain autopsies of 50 deceased ET patients ( as of December 2009 ), showed clear degenerative and pathological abnormalities, including " messy " neurofilaments which can impede nerve impulses.

The series ran on ABC Television for an hour each weekday in the 1955 – 1956 and 1956 – 1957 seasons ( from 5: 00 to 6: 00 pm ET ), and only a half-hour weekdays ( 5: 30 to 6: 00 pm ET ) in 1957 – 1958, the final season to feature new programming.

The female announcers have been featured in almost every medium including television ( CBS Sunday Morning, The Today Show, The View, Sally Jessy Raphaël, and numerous appearances on Entertainment Tonight and ET Insider ) newspapers and magazines, ( TV Guide, Playboy ) and as guests on multiple radio shows including Howard Stern.

Sometimes the sport is called Quad Hockey, Hóquei em Patins ( PT ), Rolhockey ( NL ), Rollhockey ( DE ), International Style Ball hockey, Rink Hockey ( FR ), Hockey Su Pista ( IT ), Hoquei sobre Patins ( CA ), Hockey sobre Patines ( ES ), Rulleskøjtehockey ( DA ), Rullbandy ( S ), Rulluisuhoki ( ET ) and Hardball hockey ( US ), depending on which region of the world it is played.

The orbiter was lifted up on a sling very similar to the one used at Kennedy Space Center and placed inside the Dynamic Test Stand building, and there mated to the Vertical Mate Ground Vibration Test tank ( VMGVT-ET ), which in turn was attached to a set of inert Solid Rocket Boosters ( SRB ) to form a complete shuttle launch stack, and marked the first time in the program's history that all Space Shuttle elements, an Orbiter, an External Tank ( ET ), and two SRBs, were mated together.

Prior to the closing of the Vandenberg facility, orbiters were transported from the OPF to the VAB on their undercarriages, only to be raised when the orbiter was being lifted for attachment to the SRB / ET stack.

* Ephemeris Time ( ET ) was from 1952 to 1976 an official time scale standard of the International Astronomical Union ; it was a dynamical time scale based on the orbital motion of the Earth around the Sun, from which the ephemeris second was derived as a defined fraction of the tropical year.

It provides 15 hours of prime time programming to owned-and-operated and affiliated stations: 8 – 10 p. m. Monday to Saturday ( all times ET / PT ) and 7 – 10 p. m. on Sundays.

Reruns of Match Game 74 currently air weekday mornings at 8: 30am ET on GSN

The show premiered on September 19, 1983 on CBS at 10: 30 AM ET ( 9: 30 CT / MT / PT ), replacing Child's Play, and placing it between The New $ 25, 000 Pyramid and The Price Is Right.

There is now a resort style hotel and an " ET Escape " sport fishing lodge on the island and visitors are welcome.

ET on October 7, 2002, Disney Channel introduced a new on-air appearance with a new logo designed by CA Square ( using an outline of Mickey Mouse's head as its centerpiece ) that was adopted by its international sister channels in May 2003, and unveiling a new graphics designed to fit the network's new look.

Many of the channel's earliest original movies ( particularly those made from 1997 to 2002 ) have seldom been aired by Disney Channel in recent years, except for some holiday-themed movies ; in January 2009, the channel began airing these older original movies on Friday and Saturday nights at 3 am ET / PT ; since June 2010, movies also air on Sundays in late night and since July 2010, the movies start at 2: 30 am ET / PT and some of the late-night weekend movies are aired without promo breaks.

The first game of the Saturday night doubleheader typically originates in Eastern Canada, beginning at 7 p. m. ET / 4 p. m. PT.

ESPN will air several SEC games each week among its various channels, with Saturday time slots generally at 12: 00 ET, 7: 00 ET, and 7: 45 ET, and some SEC games will be shown on Thursday nights.

ET on Univision ; as such, the program is currently one of only three remaining first-run primetime programs airing on Saturday nights on any of the American commercial broadcast television networks, along with CBS's 48 Hours Mystery and Fox's COPS.

ET with the launch of a primetime block called SNICK, which was home to shows such as Are You Afraid of the Dark ?, Clarissa Explains It All, Roundhouse, All That, The Amanda Show and Kenan & Kel ; in 2004, the block was reformatted as the Saturday edition of TEENick ( which originally debuted on Sunday evenings in 2000 ), and the Saturday night block continues today without an official block name ( though A Night of Premieres is occasionally used when two or more programs feature new episodes on that night ); the TEENick branding, with its spelling altered to TeenNick, has since been used on the Nickelodeon sister channel previously known as The N. In June 1993, Nickelodeon resumed its magazine brand, Nickelodeon Magazine.

Nickelodeon and its sister channels Nick Jr., TeenNick and Nicktoons ( along with some international versions of the channel ) suspend programming for three hours from 12 – 3 p. m. ET / PT on a Saturday afternoon in late September ( since 2005 ) during the event and show their testcards instead, and the respective websites of all four Nickelodeon channels are taken offline during that same three-hour time period.

ET, Saturday mornings, Saturday nights from 8 – 10 p. m.

ET as part of " See It Saturday ", and broadcasts a featured movie Sunday through Fridays at 10 p. m.

In the fall of 1961, ABC truncated American Bandstands airtime from 90 to 60 minutes ( 4: 00 – 5: 00pm ET ), then even further as a daily half-hour ( 4: 00 – 4: 30pm ET ) program in September 1962 ; beginning in early 1963, all five shows for the upcoming week were videotaped the preceding Saturday.

The program was broadcast live beginning at 7: 00 a. m. ET / 6: 00 a. m. CT on Saturday mornings from the GM Building on Fifth Avenue in New York City, across the street from Central Park.

ET ) and has been spoofed on the American late-night television sketch comedy Saturday Night Live.

The 2011 Fiesta Bowl took place on Saturday, January 1 at 8: 30 PM ET.

On January 21, 2006, just days after the unexpected death of his wife Ramona, Bell announced he would host Coast to Coast AM every Saturday and Sunday evening, and that former weekend host Ian Punnett would work a new live prefeed program for the four hours preceding Bell's slot on Saturday nights ( 9: 00 pm – 1: 00 am ET ).

The Clark Howard Show show on HLN runs every Saturday and Sunday at 6: 00 am, noon and 4: 00 pm ET.

ET each night and features a horror movie double feature on Saturday nights at 10 p. m.

ET as part of " Splatterday on Saturday ".