Kennelly-Heaviside layer
Encyclopedia
The Kennelly–Heaviside layer, named after Arthur Edwin Kennelly
and Oliver Heaviside
, also known as the E region or simply the Heaviside layer, is a layer of ionised gas
occurring between roughly 90–150 km (56–93 mi) above the ground
— one of several layers in the Earth
's ionosphere
. It reflects medium-frequency
radio wave
s, and because of this reflection
radio wave
s can be propagated
beyond the horizon
.
Propagation is affected by time of day. During the daytime the solar wind
presses this layer closer to the Earth, thereby limiting how far it can reflect radio waves. On the night side of the Earth, the solar wind drags the ionosphere further away, thereby greatly increasing the range which radio waves can travel by reflection, called skywave
. The extent of the effect is further influenced by the season
, and the amount of sunspot
activity.
(1861–1939) and the British physicist Oliver Heaviside
(1850–1925). However, it was not until 1924 that its existence was shown by British scientist Edward V. Appleton, for which he received the 1947 Nobel Prize in Physics
. In 1925, Americans Gregory Breit
and Merle A. Tuve first mapped its variations in altitude.
's musical Cats
. This reference is based on a quote found in a letter written by T. S. Eliot
, whose book Old Possum's Book of Practical Cats
forms the basis of the musical. In the musical, one cat is chosen each year by Old Deuteronomy
to go to the Heaviside Layer and begin a new life. In the song "The Journey to the Heaviside Layer", it is stated that the Heaviside Layer is "past the Russell Hotel
" and "past the Jellicle moon", indicating that it is very far away and difficult to access.
In the end of the musical, Grizabella
is chosen to go the Heaviside Layer. She does so by ascending on a flying tire until she reaches a structure resembling clouds, into which she disappears, although in the film version of Cats she ascends with Old Deuteronomy
and then she walks up a giant metal hand to the Heaviside layer.
Eliot also refers to the "Heaviside Layer" in his play The Family Reunion
which explores issues around the afterlife, heaven and hell.
In Tim Powers
supernatural spy novel "Declare
" the Heaviside layer is the realm of the "spirits of the upper air".
In Thomas Pynchon
's 1964 short story "The Secret Integration," a boy's dreams are affected "when the thing in the sky, the Heaviside layer, was right for it."
Arthur Edwin Kennelly
Arthur Edwin Kennelly , was an Irish-American electrical engineer.-Biography:Kennelly was born December 17, 1861 in Colaba, in South Mumbai, India and was educated at University College School in London. He was the son of an Irish naval officer Captain David Joseph Kennelly and Catherine Gibson...
and Oliver Heaviside
Oliver Heaviside
Oliver Heaviside was a self-taught English electrical engineer, mathematician, and physicist who adapted complex numbers to the study of electrical circuits, invented mathematical techniques to the solution of differential equations , reformulated Maxwell's field equations in terms of electric and...
, also known as the E region or simply the Heaviside layer, is a layer of ionised gas
Gas
Gas is one of the three classical states of matter . Near absolute zero, a substance exists as a solid. As heat is added to this substance it melts into a liquid at its melting point , boils into a gas at its boiling point, and if heated high enough would enter a plasma state in which the electrons...
occurring between roughly 90–150 km (56–93 mi) above the ground
Altitude
Altitude or height is defined based on the context in which it is used . As a general definition, altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The reference datum also often varies according to the context...
— one of several layers in the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
's ionosphere
Ionosphere
The ionosphere is a part of the upper atmosphere, comprising portions of the mesosphere, thermosphere and exosphere, distinguished because it is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere...
. It reflects medium-frequency
Mediumwave
Medium wave is the part of the medium frequency radio band used mainly for AM radio broadcasting. For Europe the MW band ranges from 526.5 kHz to 1606.5 kHz...
radio wave
Radio Wave
Radio Wave may refer to:*Radio frequency*Radio Wave 96.5, a radio station in Blackpool, UK...
s, and because of this reflection
Reflection (physics)
Reflection is the change in direction of a wavefront at an interface between two differentmedia so that the wavefront returns into the medium from which it originated. Common examples include the reflection of light, sound and water waves...
radio wave
Radio Wave
Radio Wave may refer to:*Radio frequency*Radio Wave 96.5, a radio station in Blackpool, UK...
s can be propagated
Radio propagation
Radio propagation is the behavior of radio waves when they are transmitted, or propagated from one point on the Earth to another, or into various parts of the atmosphere...
beyond the horizon
Horizon
The horizon is the apparent line that separates earth from sky, the line that divides all visible directions into two categories: those that intersect the Earth's surface, and those that do not. At many locations, the true horizon is obscured by trees, buildings, mountains, etc., and the resulting...
.
Propagation is affected by time of day. During the daytime the solar wind
Solar wind
The solar wind is a stream of charged particles ejected from the upper atmosphere of the Sun. It mostly consists of electrons and protons with energies usually between 1.5 and 10 keV. The stream of particles varies in temperature and speed over time...
presses this layer closer to the Earth, thereby limiting how far it can reflect radio waves. On the night side of the Earth, the solar wind drags the ionosphere further away, thereby greatly increasing the range which radio waves can travel by reflection, called skywave
Skywave
Skywave is the propagation of electromagnetic waves bent back to the Earth's surface by the ionosphere. As a result of skywave propagation, a broadcast signal from a distant AM broadcasting station at night, or from a shortwave radio station can sometimes be heard as clearly as local...
. The extent of the effect is further influenced by the season
Season
A season is a division of the year, marked by changes in weather, ecology, and hours of daylight.Seasons result from the yearly revolution of the Earth around the Sun and the tilt of the Earth's axis relative to the plane of revolution...
, and the amount of sunspot
Sunspot
Sunspots are temporary phenomena on the photosphere of the Sun that appear visibly as dark spots compared to surrounding regions. They are caused by intense magnetic activity, which inhibits convection by an effect comparable to the eddy current brake, forming areas of reduced surface temperature....
activity.
History
Its existence was predicted in 1902 independently and almost simultaneously by the American electrical engineer Arthur Edwin KennellyArthur Edwin Kennelly
Arthur Edwin Kennelly , was an Irish-American electrical engineer.-Biography:Kennelly was born December 17, 1861 in Colaba, in South Mumbai, India and was educated at University College School in London. He was the son of an Irish naval officer Captain David Joseph Kennelly and Catherine Gibson...
(1861–1939) and the British physicist Oliver Heaviside
Oliver Heaviside
Oliver Heaviside was a self-taught English electrical engineer, mathematician, and physicist who adapted complex numbers to the study of electrical circuits, invented mathematical techniques to the solution of differential equations , reformulated Maxwell's field equations in terms of electric and...
(1850–1925). However, it was not until 1924 that its existence was shown by British scientist Edward V. Appleton, for which he received the 1947 Nobel Prize in Physics
Nobel Prize in Physics
The Nobel Prize in Physics is awarded once a year by the Royal Swedish Academy of Sciences. It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895 and awarded since 1901; the others are the Nobel Prize in Chemistry, Nobel Prize in Literature, Nobel Peace Prize, and...
. In 1925, Americans Gregory Breit
Gregory Breit
Gregory Breit was a Russian-born American physicist and professor at universities in New York, Wisconsin, Yale, and Buffalo...
and Merle A. Tuve first mapped its variations in altitude.
Cultural impact
The "Heaviside layer" is used as a symbol for heaven (in the afterlife sense) in Andrew Lloyd WebberAndrew Lloyd Webber
Andrew Lloyd Webber, Baron Lloyd-Webber is an English composer of musical theatre.Lloyd Webber has achieved great popular success in musical theatre. Several of his musicals have run for more than a decade both in the West End and on Broadway. He has composed 13 musicals, a song cycle, a set of...
's musical Cats
Cats (musical)
Cats is a musical composed by Andrew Lloyd Webber, based on Old Possum's Book of Practical Cats by T. S. Eliot...
. This reference is based on a quote found in a letter written by T. S. Eliot
T. S. Eliot
Thomas Stearns "T. S." Eliot OM was a playwright, literary critic, and arguably the most important English-language poet of the 20th century. Although he was born an American he moved to the United Kingdom in 1914 and was naturalised as a British subject in 1927 at age 39.The poem that made his...
, whose book Old Possum's Book of Practical Cats
Old Possum's Book of Practical Cats
Old Possum's Book of Practical Cats is a collection of whimsical poems by T. S. Eliot about feline psychology and sociology, published by Faber and Faber. It is the basis for the record-setting musical Cats....
forms the basis of the musical. In the musical, one cat is chosen each year by Old Deuteronomy
Old Deuteronomy
Old Deuteronomy is a character in T. S. Eliot's Old Possum's Book of Practical Cats and its musical adaptation, Cats.In Eliot's original poem, Old Deuteronomy is described as an ancient, wise cat who has "lived many lives in succession" and is respected by the other cats and humans in his...
to go to the Heaviside Layer and begin a new life. In the song "The Journey to the Heaviside Layer", it is stated that the Heaviside Layer is "past the Russell Hotel
Hotel Russell
The Hotel Russell is a four star hotel, located on Russell Square, Bloomsbury, London, owned and operated by the Principal Hayley Group.The Hotel Russell was built in 1898 by the architect, Charles Fitzroy Doll. It is distinctively clad in decorative thé-au-lait terracotta, and was based on the...
" and "past the Jellicle moon", indicating that it is very far away and difficult to access.
In the end of the musical, Grizabella
Grizabella
Grizabella is the "Glamour Cat" in the musical production Cats. She does not appear in T. S. Eliot's work Old Possum's Book of Practical Cats, but she is a prominent character in the stageplay. It appears that she is the feline version of the woman mentioned in T.S...
is chosen to go the Heaviside Layer. She does so by ascending on a flying tire until she reaches a structure resembling clouds, into which she disappears, although in the film version of Cats she ascends with Old Deuteronomy
Old Deuteronomy
Old Deuteronomy is a character in T. S. Eliot's Old Possum's Book of Practical Cats and its musical adaptation, Cats.In Eliot's original poem, Old Deuteronomy is described as an ancient, wise cat who has "lived many lives in succession" and is respected by the other cats and humans in his...
and then she walks up a giant metal hand to the Heaviside layer.
Eliot also refers to the "Heaviside Layer" in his play The Family Reunion
The Family Reunion
The Family Reunion is a play by T. S. Eliot. Written mostly in blank verse, it incorporates elements from Greek drama and mid-twentieth-century detective plays to portray the hero's journey from guilt to redemption. The play was unsuccessful when first presented in 1939, and was later regarded as...
which explores issues around the afterlife, heaven and hell.
In Tim Powers
Tim Powers
Timothy Thomas "Tim" Powers is an American science fiction and fantasy author. Powers has won the World Fantasy Award twice for his critically acclaimed novels Last Call and Declare...
supernatural spy novel "Declare
Declare
Declare is a supernatural spy novel by Tim Powers. It presents a secret history of the Cold War in which an agent for a secret British spy organization learns the true nature of several beings living on Mount Ararat. In this he is opposed by real-life communist traitor Kim Philby, who did travel...
" the Heaviside layer is the realm of the "spirits of the upper air".
In Thomas Pynchon
Thomas Pynchon
Thomas Ruggles Pynchon, Jr. is an American novelist. For his most praised novel, Gravity's Rainbow, Pynchon received the National Book Award, and is regularly cited as a contender for the Nobel Prize in Literature...
's 1964 short story "The Secret Integration," a boy's dreams are affected "when the thing in the sky, the Heaviside layer, was right for it."