Water vapor (H2O)
Water vapor condensed in clouds
Systematic name	Water vapor
Liquid State	water
Solid state	ice
Properties[1]
Molecular formula	H2O
Molar mass	18.01528(33) g/mol
Melting point	0 °C (273 K)[2]
Boiling point	99.98 °C (373.13 K)[2]
specific gas constant	461.5 J/(kg·K)
Heat of vaporization	2.27 MJ/kg
Heat capacity at 300 K	1.864 kJ/(kg·K)[3]

Water vapor or water vapour (see spelling differences), also aqueous vapor, is the gas phase of water. It is one state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice. Under typical atmospheric conditions, water vapor is continuously generated by evaporation and removed by condensation. It is lighter than air and triggers convection currents that can lead to clouds.

Water vapor is a potent greenhouse gas along with other gases such as carbon dioxide and methane.

General properties of water vapor[link]

Evaporation and sublimation[link]

Whenever a water molecule leaves a surface and diffuses into a surrounding gas, it is said to have evaporated. Each individual water molecule which transitions between a more associated (liquid) and a less associated (vapor/gas) state does so through the absorption or release of kinetic energy. The aggregate measurement of this kinetic energy transfer is defined as thermal energy and occurs only when there is differential in the temperature of the water molecules. Liquid water that becomes water vapor takes a parcel of heat with it, in a process called evaporative cooling.^[4] The amount of water vapor in the air determines how fast each molecule will return back to the surface. When a net evaporation occurs, the body of water will undergo a net cooling directly related to the loss of water.

In the US, the National Weather Service measures the actual rate of evaporation from a standardized "pan" open water surface outdoors, at various locations nationwide. Others do likewise around the world. The US data is collected and compiled into an annual evaporation map.^[5] The measurements range from under 30 to over 120 inches per year. Formulas can be used for calculating the rate of evaporation from a water surface such as a swimming pool.^[6][7]

Evaporative cooling is restricted by atmospheric conditions. Humidity is the amount of water vapor in the air. The vapor content of air is measured with devices known as hygrometers. The measurements are usually expressed as specific humidity or percent relative humidity. The temperatures of the atmosphere and the water surface determine the equilibrium vapor pressure; 100% relative humidity occurs when the partial pressure of water vapor is equal to the equilibrium vapor pressure. This condition is often referred to as complete saturation. Humidity ranges from 0 gram per cubic metre in dry air to 30 grams per cubic metre (0.03 ounce per cubic foot) when the vapor is saturated at 30 °C.^[8] (See also Absolute Humidity table)

Meteorite Recovery Antarctica

Electron micrograph of tight junctions in blood–brain barrier, prepared by sublimation in freeze-etching process.

Another form of evaporation is sublimation, by which water molecules become gaseous directly, leaving the surface of ice without first becoming liquid water. Sublimation accounts for the slow mid-winter disappearance of ice and snow at temperatures too low to cause melting. Antarctica shows this effect to a unique degree because it is by far the continent with the lowest rate of precipitation on Earth. As a result there are large areas where millennial layers of snow have sublimed, leaving behind whatever non-volatile materials they had contained. This is extremely valuable to certain scientific disciplines, a dramatic example being the collection of meteorites that are left exposed in unparalleled numbers and excellent states of preservation.

Sublimation is of importance in the preparation of certain classes of biological specimens for scanning electron microscopy. Typically the specimens are prepared by cryofixation and freeze-fracture, after which the broken surface is freeze-etched, being eroded by exposure to vacuum till it shows the required level of detail. This technique can display protein molecules, organelle structures and lipid bilayers with very low degrees of distortion.

Condensation[link]

Clouds, formed by condensed water vapor.

Water vapor will only condense onto another surface when that surface is cooler than the dew point temperature, or when the water vapor equilibrium in air has been exceeded. When water vapor condenses onto a surface, a net warming occurs on that surface. The water molecule brings heat energy with it. In turn, the temperature of the atmosphere drops slightly.^[9] In the atmosphere, condensation produces clouds, fog and precipitation (usually only when facilitated by cloud condensation nuclei). The dew point of an air parcel is the temperature to which it must cool before water vapor in the air begins to condense.

Also, a net condensation of water vapor occurs on surfaces when the temperature of the surface is at or below the dew point temperature of the atmosphere. Deposition, the direct formation of ice from water vapor, is a type of condensation. Frost and snow are examples of deposition.

Chemical reactions[link]

A number of chemical reactions have water as a product. If the reactions take place at temperatures higher than the dew point of the surrounding air the water will be formed as vapour and increase the local humidity, if below the dew point local condensation will occur. Typical reactions that result in water formation are the burning of hydrogen or many other hydrocarbons in air itself or in combination with oxygen or other oxidisers.

In a similar fashion other chemical or physical reactions can take place in the presence of water vapour resulting in new chemicals forming such as rust on iron or steel, polymerisation occurring (certain polyurethane foams and cyanoacrylate glues cure with exposure to atmospheric humidity) or forms changing such as where anhydrous chemicals may absorb enough vapour to form a crystalline structure or alter an existing one, sometimes resulting in characteristic colour changes that can be used for measurement.

Measurement[link]

Measuring the quantity of water vapor in a medium can be done directly or remotely with varying degrees of accuracy. Remote methods such electromagnetic absorption are possible from satellites above planetary atmospheres. Direct methods may use electronic transducers, moistened thermometers or hygroscopic materials measuring changes in physical properties or dimensions.

Water vapor density[link]

Water vapor is lighter or less dense than dry air. At equivalent temperatures it is buoyant with respect to dry air.

Water vapor and dry air density calculations at 0 °C[link]

The molar mass of water is 18.02 g/mol, as calculated from the sum of the atomic masses of its constituent atoms.

The average molecular mass of air (approx. 79% nitrogen, N₂; 21% oxygen, O₂) is 28.57 g/mol at standard temperature and pressure (STP).

Using Avogadro's Law and the ideal gas law, water vapor and air will have a molar volume of 22.414 litre/mol at STP. A molar mass of air and water vapor occupy the same volume of 22.414 litres. The density (mass/volume) of water vapor is 0.804 g/litre, which is significantly less than that of dry air at 1.27 g/liter at STP.

STP conditions imply a temperature of 0 °C, at which the ability of water to become vapor is very restricted. Its concentration in air is very low at 0 °C. The red line on the chart to the right is the maximum concentration of water vapor expected for a given temperature. The water vapor concentration increases significantly as the temperature rises, approaching 100% (steam, pure water vapor) at 100 °C. However the difference in densities between air and water vapor would still exist.

Air and water vapor density interactions at equal temperatures[link]

At the same temperature, a column of dry air will be denser or heavier than a column of air containing any water vapor. Thus, any volume of dry air will sink if placed in a larger volume of moist air. Also, a volume of moist air will rise or be buoyant if placed in a larger region of dry air. As the temperature rises the proportion of water vapor in the air increases, and its buoyancy will increase. The increase in buoyancy can have a significant atmospheric impact, giving rise to powerful, moisture rich, upward air currents when the air temperature and sea temperature reaches 25 °C or above. This phenomenon provides a significant motivating force for cyclonic and anticyclonic weather systems (tornadoes and hurricanes).

Water vapor and respiration or breathing[link]

Water vapor is a by-product of respiration in plants and animals. Its contribution to the pressure, increases as its concentration increases. Its partial pressure contribution to air pressure increases, lowering the partial pressure contribution of the other atmospheric gases (Dalton's Law). The total air pressure must remain constant. The presence of water vapor in the air naturally dilutes or displaces the other air components as its concentration increases.

This can have an effect on respiration. In very warm air (35 °C) the proportion of water vapor is large enough to give rise to the stuffiness that can be experienced in humid jungle conditions or in poorly ventilated buildings.

Lifting gas[link]

Due to its low molecular weight, water vapor is a lifting gas under STP conditions, though it is limited by the low amount of water vapor which can exist in the air at a given point in time. High enough temperatures to maintain a theoretical "steam balloon" yield approximately 60% the lift of helium and twice that of hot air.^[10]

General discussion[link]

The amount of water vapor in an atmosphere is constrained by the restrictions of partial pressures and temperature. Dew point temperature and relative humidity act as guidelines for the process of water vapor in the water cycle. Energy input, such as sunlight, can trigger more evaporation on an ocean surface or more sublimation on a chunk of ice on top of a mountain. The balance between condensation and evaporation gives the quantity called vapor partial pressure.

The maximum partial pressure (saturation pressure) of water vapor in air varies with temperature of the air and water vapor mixture. A variety of empirical formulas exist for this quantity; the most used reference formula is the Goff-Gratch equation for the SVP over liquid water below zero degree Celsius:

Where T, temperature of the moist air, is given in units of kelvins, and p is given in units of millibars (hectopascals).

The formula is valid from about −50 to 102 °C; however there are a very limited number of measurements of the vapor pressure of water over supercooled liquid water. There are a number of other formulae which can be used.^[11]

Under certain conditions, such as when the boiling temperature of water is reached, a net evaporation will always occur during standard atmospheric conditions regardless of the percent of relative humidity. This immediate process will dispel massive amounts of water vapor into a cooler atmosphere.

Exhaled air is almost fully at equilibrium with water vapor at the body temperature. In the cold air the exhaled vapor quickly condenses, thus showing up as a fog or mist of water droplets and as condensation or frost on surfaces. Forcibly condensing these water droplets from exhaled breath is the basis of exhaled breath condensate, an evolving medical diagnostic test.

Controlling water vapor in air is a key concern in the heating, ventilating, and air-conditioning (HVAC) industry. Thermal comfort depends on the moist air conditions. Non-human comfort situations are called refrigeration, and also are affected by water vapor. For example many food stores, like supermarkets, utilize open chiller cabinets, or food cases, which can significantly lower the water vapor pressure (lowering humidity). This practice delivers several benefits as well as problems.

Water vapor in Earth's atmosphere[link]

Gaseous water represents a small but environmentally significant constituent of the atmosphere. The percentage water vapor in surface air varies from a trace in desert regions to about 4% over oceans.^[12] Approximately 99.13% of it is contained in the troposphere. The condensation of water vapor to the liquid or ice phase is responsible for clouds, rain, snow, and other precipitation, all of which count among the most significant elements of what we experience as weather. Less obviously, the latent heat of vaporization, which is released to the atmosphere whenever condensation occurs, is one of the most important terms in the atmospheric energy budget on both local and global scales. For example, latent heat release in atmospheric convection is directly responsible for powering destructive storms such as tropical cyclones and severe thunderstorms. Water vapor is also the most potent greenhouse gas owing to the presence of the hydroxyl bond which strongly absorbs in the infra-red region of the light spectrum. Because the water vapor content of the atmosphere will increase in response to warmer temperatures, there is a water vapor feedback which is expected to amplify the climate warming effect due to increased carbon dioxide alone. It is less clear how cloudiness would respond to a warming climate; depending on the nature of the response, clouds could either further amplify or partly mitigate warming from long-lived greenhouse gases.

Fog and clouds form through condensation around cloud condensation nuclei. In the absence of nuclei, condensation will only occur at much lower temperatures. Under persistent condensation or deposition, cloud droplets or snowflakes form, which precipitate when they reach a critical mass.

Increasing stratospheric water vapor at Boulder, Colorado.

The water content of the atmosphere as a whole is constantly depleted by precipitation. At the same time it is constantly replenished by evaporation, most prominently from seas, lakes, rivers, and moist earth. Other sources of atmospheric water include combustion, respiration, volcanic eruptions, the transpiration of plants, and various other biological and geological processes. The mean global content of water vapor in the atmosphere is roughly sufficient to cover the surface of the planet with a layer of liquid water about 25 mm deep. The mean annual precipitation for the planet is about 1 meter, which implies a rapid turnover of water in the air – on average, the residence time of a water molecule in the troposphere is about 9 to 10 days.

Episodes of surface geothermal activity, such as volcanic eruptions and geysers, release variable amounts of water vapor into the atmosphere. Such eruptions may be large in human terms, and major explosive eruptions may inject exceptionally large masses of water exceptionally high into the atmosphere, but as a percentage of total atmospheric water, the role of such processes is minor. The relative concentrations of the various gases emitted by volcanoes varies considerably according to the site and according to the particular event at any one site. However, water vapor is consistently the commonest volcanic gas; as a rule, it comprises more than 60% of total emissions during a subaerial eruption.^[13]

Atmospheric water vapor content is expressed using various measures. These include vapor pressure, specific humidity, mixing ratio, dew point temperature, and relative humidity.

Radar and satellite imaging[link]

MODIS/Terra global mean atmospheric water vapor

Because water molecules absorb microwaves and other radio wave frequencies, water in the atmosphere attenuates radar signals.^[14] In addition, atmospheric water will reflect and refract signals to an extent that depends on whether it is vapor, liquid or solid.

Generally, radar signals lose strength progressively the farther they travel through the troposphere. Different frequencies attenuate at different rates, such that some components of air are opaque to some frequencies and transparent to others. Radio waves used for broadcasting and other communication experience the same effect.

Water vapor reflects radar to a lesser extent than do water's other two phases. In the form of drops and ice crystals, water acts as a prism, which it does not do as an individual molecule; however, the existence of water vapor in the atmosphere causes the atmosphere to act as a giant prism.^[15]

A comparison of GOES-12 satellite images shows the distribution of atmospheric water vapor relative to the oceans, clouds and continents of the Earth. Vapor surrounds the planet but is unevenly distributed.

Lightning generation[link]

Water vapor plays a key role in lightning production in the atmosphere. From cloud physics, usually, clouds are the real generators of static charge as found in Earth's atmosphere. But the ability, or capability of clouds to hold massive amounts of electrical energy is directly related to the amount of water vapor present in the local system.

The amount of water vapor directly controls the permittivity of the air. During times of low humidity, static discharge is quick and easy. During times of higher humidity, fewer static discharges occur. Permittivity and capacitance work hand in hand to produce the megawatt outputs of lightning.^[16]

After a cloud, for instance, has started its way to becoming a lightning generator, atmospheric water vapor acts as a substance (or insulator) that decreases the ability of the cloud to discharge its electrical energy. Over a certain amount of time, if the cloud continues to generate and store more static electricity, the barrier that was created by the atmospheric water vapor will ultimately break down from the stored electrical potential energy.^[17][18] This energy will be released to a locally, oppositely charged region in the form of lightning. The strength of each discharge is directly related to the atmospheric permittivity, capacitance, and the source's charge generating ability.^[19]

See also, Van de Graaff generator.

Extraterrestrial water vapor[link]

The brilliance of comet tails comes largely from water vapor. On approach to the sun, the ice many comets carry sublimates to vapor, which reflects light from the sun. Knowing a comet's distance from the sun, astronomers may deduce a comet's water content from its brilliance.^[20] Bright tails in cold and distant comets suggests carbon monoxide sublimation.

Scientists studying Mars hypothesize that if water moves about the planet, it does so as vapor.^[21] Most of the water on Mars appears to exist as ice at the northern pole. During Mars' summer, this ice sublimates, perhaps enabling massive seasonal storms to convey significant amounts of water toward the equator.^[22]

A star called CW Leonis was found to have a ring of vast quantities of water vapor circling the aging, massive star. A NASA satellite designed to study chemicals in interstellar gas clouds, made the discovery with an onboard spectrometer. Most likely, "the water vapor was vaporized from the surfaces of orbiting comets."^[23]

Spectroscopic analysis of HD 209458 b, an extrasolar planet in the constellation Pegasus, provides the first evidence of atmospheric water vapor beyond the Solar System.

See also[link]

Wikimedia Commons has media related to: Water vapor

References[link]

External links[link]

• National Science Digital Library – Water Vapor
• Calculate the condensation of your exhaled breath
• Water Vapor Myths: A Brief Tutorial
• AGU Water Vapor in the Climate System – 1995
• Free Windows Program, Water Vapor Pressure Units Conversion Calculator – PhyMetrix

Katherine Heigl
Katherine Heigl in 2008
Born	Katherine Marie Heigl (1978-11-24) November 24, 1978 (age 33) Washington, D.C., U.S.
Other names	Katie
Occupation	Actress, producer
Years active	1992–present
Spouse	Josh Kelley (m. 2007) «start: (2007)»"Marriage: Josh Kelley to Katherine Heigl" Location: (linkback:http://en-wiki.pop.wn.com/index.php/Katherine_Heigl)
Children	2
Website
www.kheigl.com

Katherine Marie Heigl ( /ˈhaɪɡəl/;^[1] born November 24, 1978)^[2] is an American actress and producer. She is possibly best known for her role as Dr. Izzie Stevens on ABC's Grey's Anatomy from 2005 to 2010, for which she won a Primetime Emmy Award for Outstanding Supporting Actress – Drama Series in 2007. She has also starred in films such as Under Siege 2: Dark Territory, Knocked Up, Zyzzyx Road, 27 Dresses, The Ugly Truth, Killers, Life As We Know It, New Year's Eve, and One for the Money.

Heigl started her career as a child model with Wilhelmina Models before she turned her attention to acting. She made her debut in the coming-of-age film That Night. Heigl co-starred as Isabel Evans in the television series Roswell and movies including My Father the Hero before landing her break-out role in Grey's Anatomy. Heigl has established herself as a cover model appearing on numerous publications including Maxim, Vanity Fair and Cosmopolitan.^[2]

Heigl is married to singer Josh Kelley, with whom she has two daughters.

Early life[link]

Heigl was born in Washington, D.C., at Columbia Hospital for Women.^[3] She is the daughter of Nancy (née Engelhardt), a personnel manager, and Paul Heigl, a financial executive and accountant.^[4][5] Heigl has German and Irish ancestry,^[6] and was raised in The Church of Jesus Christ of Latter-day Saints.^[7][8][9] She is the youngest of four children (her siblings are Meg, Jason (deceased), and Holt).^[10] Heigl lived in Virginia and then Denver before her family settled in Connecticut, when they moved into a large, old Victorian-style farmhouse in the wealthy town of New Canaan, where she spent most of her childhood.^[11]

In 1986, her older brother Jason died of injuries suffered in a car accident, after being thrown from the back of a pickup truck while out for lunch with some of his high school classmates. Following his death, the family decided to donate his organs.^[12] Heigl was unnerved by this at the time, and later became a strong proponent of organ donation, working as a spokesperson for Donate Life America.^[13] After Jason Heigl's death, their parents converted to The Church of Jesus Christ of Latter-day Saints (prior to that her mother was Lutheran and her father Catholic).^{[10][14][15][16]}

Career[link]

Early work, 1986–1998[link]

When Heigl was nine, an aunt visiting the family decided to take a number of photographs of her. After returning to her home in New York, her aunt sent the photos to a number of modeling agencies, with the permission of Heigl's parents. Within a few weeks, Heigl was signed with Wilhelmina Models as a child model.^[17] Soon after signing with the agency, a client slated Heigl for use in a magazine advertisement where she made her debut. At the time, she was earning $75 an hour posing for Sears and Lord & Taylor catalogs. Heigl appeared in her first national television spot for Cheerios cereal.

She made her acting debut in the 1992 movie That Night. Heigl appeared as Christina Sebastian in Steven Soderbergh's Depression-era drama King of the Hill before being cast in her first leading role in the 1994 comedy My Father the Hero. During this time, Heigl continued to attend New Canaan High School, balancing her film and modeling work with her academic studies. Heigl dropped out of New Canaan High School after her sophomore year to pursue her career in Hollywood.

In 1995, she starred in the Steven Seagal action thriller Under Siege 2: Dark Territory. Heigl portrayed a 16-year-old travelling on a train across a mountain pass to visit the grave of her deceased father with uncle Casey Ryback (Seagal), an ex-SEAL counter-terrorist expert. The main plotline has the train hijacked by mercenaries in Colorado, keeping her as a hostage. Much of her work in the film was opposite Morris Chestnut, Sandra Taylor and Everett McGill.

Despite an increased focus on acting, she still modeled extensively, appearing regularly in magazines such as Seventeen. She landed the lead role in Disney's made-for-television film Wish Upon a Star in 1996, portraying two body-swapping characters along with Danielle Harris. Also in 1996, Heigl's parents divorced and her mother was diagnosed with cancer.^[10] After her high school graduation in 1997, she moved with her mother into a four-bedroom house in Malibu Canyon, Los Angeles, and her mother became her manager.

In 1998, she co-starred with Peter Fonda in a re-working of the classic Shakespearean play The Tempest, set during the American Civil War. Later that year, she starred in the horror film Bride of Chucky.

Rise to fame, 1999–2004[link]

In 1999, Heigl turned her attention to television when she accepted the role of Isabel Evans on the science fiction TV drama Roswell, a role that was expanded in the show's second and third seasons. Heigl had auditioned for all three of the show's female leads (the other two roles eventually went to Shiri Appleby and Majandra Delfino) before she was finally cast as Isabel, an alien human hybrid.^[18]

Heigl was frequently featured in photo essays in magazines such as Life, TV Guide, and Teen as well as FHM. She appeared in the FHM and Maxim calendars, FHM's annual "100 Sexiest Women in the World", and was featured in the Girls of Maxim Gallery.^[19] In May 2006, Maxim awarded her #12 on their annual Hot 100List as well as voted the 19th "Sexiest Woman in the World" by readers of FHM magazine. While Roswell was in production, Heigl worked on several films, including 100 Girls, an independent 2001 film, and Valentine, a horror film starring David Boreanaz and Denise Richards.^[20]

Heigl accepted a role in Ground Zero, a television thriller scheduled to be telecast that fall which was based on the bestselling James Mills novel The Seventh Power, in the spring of 2001. She co-starred as a brilliant and politically-concerned college student who helps to build a nuclear device to illustrate the need for a change in national priorities. The device ends up in the hands of a terrorist following betrayal by a fellow student. However, after the September 11, 2001 terrorist attacks, the film was shelved when its plot was considered inappropriate. It reemerged in 2003 under the title Critical Assembly. After the attacks, Heigl recorded a public service announcement for the American Red Cross in an effort to help raise money for victims.

In 2003, Heigl appeared in three television movies. She returned to the horror genre with Evil Never Dies, a modern-day variation on the Frankenstein story co-starring Thomas Gibson. Love Comes Softly, for Hallmark Entertainment, found Heigl starring as Marty Claridge, a young, pregnant newlywed traveling west. (She reprised the role of Marty in the sequel Love's Enduring Promise the next year.) Heigl played Isabella Linton in MTV's modern revamp of Emily Brontë's Wuthering Heights. In October 2003, Heigl was cast opposite Johnny Knoxville in The Ringer, a Farrelly brothers comedy that was released in December 2005. Heigl starred as Romy in the 2005 television movie Romy and Michele: In the Beginning, a prequel to the 1997 film Romy and Michele's High School Reunion.

Breakthrough, 2005–present[link]

In 2005, Heigl was cast in what would become her most high-profile role to date, as medical intern Dr. Isobel "Izzie" Stevens on Grey's Anatomy, an ABC medical drama. The show, originally introduced as a mid-season replacement, became a huge ratings success and is still one of the highest-rated television series on broadcast television. The same year, Heigl landed the starring role in the independent film, Side Effects,^[21] a romantic comedy about marketing and the pharmaceutical industry, where she was also executive producer. In late 2006, Heigl was nominated for a Golden Globe award in the category Best Supporting Actress in a Series, Mini-series, or Motion Picture Made for Television for her work on Grey's Anatomy. Also in 2006, she filmed Knocked Up, a comedy from writer/director Judd Apatow, starring opposite Seth Rogen, Paul Rudd, and Apatow's real life wife, Leslie Mann. Upon its June 2007 theatrical release, the film received largely positive reviews from critics, and proved to be a box office success. Heigl won greater financial after the film's success. The movie grossed $148,761,765 in the U.S., for which she earned a salary of $300,000 USD.^[22] In a highly-publicized Vanity Fair Heigl admitted that though she enjoyed working with Apatow and Rogen when she starred in Knocked Up, she had a hard time enjoying the film itself. She called the movie "a little sexist", claiming that the film "paints the women as shrews, as humorless and uptight, and it paints the men as lovable, goofy, fun-loving guys".^[23] In his review for The Guardian, humorist Joe Queenan called Knocked Up "the latest in a new genre of romantic comedies in which an unappealing hero gets together with a gorgeous, successful woman".^[24]

Heigl's comments spurred widespread reaction in the media, primarily consisting of personal attacks in which she was called "an ungrateful traitor", "hypocrite", and "assertive, impatient go-getter who quickly tired of waiting for her boyfriend to propose", in some cases debasing her religious beliefs and criticizing her private relationships.^[25][26] Heigl clarified her remarks to People magazine, stating that, "My motive was to encourage other women like myself to not take that element of the movie too seriously and to remember that it's a broad comedy", adding that, "Although I stand behind my opinion, I'm disheartened that it has become the focus of my experience with the movie".^[27] Despite her run of success, she also starred in the box office bomb Zyzzyx Road which despite being filmed in 2004, was not released until 2006. It has been cited as the lowest grossing film of all time.^{[citation needed]} She has been on FHM's "100 Sexiest Women in the World" list twice as of 2007.

Heigl at the 59th Annual Emmy Awards in 2007

On September 16, 2007, Heigl won an Emmy for Outstanding Supporting Actress in a Drama Series for her role as Izzie Stevens. In her acceptance speech she acknowledged that even her mother did not believe she would win, and when her name was called, she had to be censored vocally by the telecast's producers, due to her saying "Shit!" when she reacted to the win.^[28] Earlier, she had corrected telecast announcer Rebecca Riedy, who had been given an incorrect phonetic spelling of Heigl's name, when she mispronounced her name as Hi-jell before the presentation of the award with Kyle Chandler for Outstanding Supporting Actor in a Miniseries or Movie. In January 2008 she starred in the film, 27 Dresses, for which she was paid $6 million USD, and appeared alongside James Marsden.^[22] Following the release of 27 Dresses, the New York Post expressed some disappointment with the mismatch of Heigl's talent with the "chick-flick" triviality of the film, suggesting that Heigl might be more compatible "with female directors such as Kimberly Peirce (Boys Don't Cry) or Tamara Jenkins (The Savages)...".^[29]

Heigl was announced the Most Desirable Woman of 2008, according to AskMen.com.^[30]

There was some speculation that Heigl might be leaving Grey's Anatomy after the end of the 2008–2009 season. This speculation revolved around her refusal to put her name in for Emmy Award^[31] consideration and the time she had devoted to producing a film version of Carolyn Jessop's book Escape.^{[32][33][34][35]} Grey's showrunner Shonda Rhimes said she was not insulted by Heigl's Emmy withdrawal, but also noted that Heigl's character Izzie had less to do during the season because Heigl asked for a light work schedule.^[36] However, despite Heigl's reported displeasure with the previous season as well as suggestions that her character had died, Heigl's return for the sixth season of Grey's has been confirmed by ABC.^{[37][38][39][40]}

In 2009, Heigl starred opposite Gerard Butler in The Ugly Truth, which opened July 24.^[41]

In June 2010, Heigl starred in the Lionsgate comedy-thriller Killers, opposite Ashton Kutcher, and then starred in and produced the big-screen drama Life As We Know It, directed by Greg Berlanti, which revolved around a woman and a man whose respective best friends die in a car accident; following the tragedy, they are left to share in caring for the deceased's orphaned daughter. Heigl received $12 million for both films.^[42]

Whether or not Heigl would leave Grey's Anatomy remained to be seen for the bigger part of season six.^[43] However, on March 11, 2010, Heigl reportedly did not show up for work when she was supposed to, and she and Shonda Rhimes had apparently come to an agreement to release her from her contract immediately. Therefore, Heigl's last appearance on the January 21 episode of Grey's Anatomy is also her final appearance on the season. Heigl said that her departure was not about advancing her film career but that she wanted to focus more on her family.^[44][45][46]

In January 2012, Heigl stated in an interview that she has asked the producers of Grey's Anatomy if she could return to the show to wrap up Izzie's storyine: "I’ve told them I want to [return],” she said. “I really, really, really want to see where [Izzie] is. I just want to know what happened to her and where she went and what she’s doing now. My idea is that she actually like figures it out, and finds some success and does really well in a different hospital. She was always floundering you know, and so she was always one step behind the eight ball and I want to see that girl take some power back."^[47][48] She also went on to say that she regrets leaving the show: "Oh yeah, sometimes, yeah. You miss it. I miss my friends. It was a great work environment ... and it becomes a family. I spent six years together with these people every day ... you grow up together, in a way," and again commented on the possibilty of Izzie returning to the show, "I always felt that if they wanted me to come back and sort of wrap up that storyline ... I want them to know that I'm down with it if they want me to, but I completely understand if it doesn't necessarily work ... They've got a lot of story lines going on there."^[49]

Charity work[link]

Heigl has worked with Best Friends Animal Society on several projects including their Pup My Ride program. The program transports small dogs from high-kill animal shelters to other parts of the US where there is a greater demand for such dogs. Her involvement in this led her to give Best Friends a grant which would fund a year of the program.^[50]

Heigl and her mother, Nancy, then started Heigl's Hounds of Hope which operates as part of the Jason Debus Heigl Foundation. The Foundation was created in honor of Katherine's brother, who was killed in a car accident in 1986 at the age of fifteen. Heigl's Hounds of Hope rescues larger dogs with behavior problems from shelters with a high kill rate and rehabilitates them through training and other adjustments to make them suitable for re-homing.^[50]

As of 2009, Heigl had six dogs of her own.^[50]

Personal life[link]

In June 2006, Heigl became engaged to singer Josh Kelley, whom she had met a year earlier on the set of his music video for "Only You".^[51] They chose not to live together before they were married, with Heigl later explaining, "I think I just wanted to save something for the actual marriage... I wanted there to be something to make the actual marriage different than the dating or the courtship."^[52] They were married on December 23, 2007 in Park City, Utah.

On September 9, 2009, Heigl's representative said the couple had started the process of adopting a baby girl from South Korea.^[53] Later that month, the couple adopted a special needs baby girl they named Nancy Leigh (after Heigl's mother and sister, respectively), nicknamed Naleigh. Heigl's sister is Korean-born and was adopted before Heigl was born.^[54] The baby had to have a congenital heart defect repaired with open heart surgery before she had left Korea.^[55] Kelley and Heigl adopted a second daughter in April 2012, named Adalaide Marie Hope Kelley.^[56][57]

Filmography[link]

References[link]

External links[link]

Wikiquote has a collection of quotations related to: Katherine Heigl

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• Official website
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David Letterman
Letterman performing on his show in June 2011.
Pseudonym	Earl Hofert
Born	(1947-04-12) April 12, 1947 (age 65) Indianapolis, Indiana, United States[1]
Medium	Stand-up, talk show
Nationality	American
Years active	1974–present
Genres	Observational comedy, surreal humor, deadpan
Subject(s)	Self-deprecation, everyday life
Influences	Steve Allen,[citation needed] Johnny Carson,[2] Jack Paar,[citation needed] Paul Dixon[3]
Influenced	Jimmy Kimmel, Jim Gaffigan, Jon Stewart, Conan O'Brien, Jimmy Fallon
Spouse	Michelle Cook (1969–1977) Regina Lasko (2009–present)
Domestic partner(s)	Regina Lasko (1986–2009)
Notable works and roles	Host of The David Letterman Show (NBC) Host of Late Night with David Letterman (NBC) Host of Late Show with David Letterman (CBS)
Signature
Website	CBS.com/latenight/lateshow
Emmy Awards
Outstanding Host or Hostess in a Variety Series 1981 The David Letterman Show Outstanding Individual Achievement — Writers 1981 The David Letterman Show Outstanding Writing in a Variety or Music Program 1984 Late Night with David Letterman 1985 Late Night with David Letterman 1986 Late Night with David Letterman 1987 Late Night with David Letterman Outstanding Variety, Music or Comedy Series 1994 Late Show with David Letterman
American Comedy Awards
Funniest Male Performer in a TV Special (Leading or Supporting) Network, Cable or Syndication 1989 Late Night with David Letterman 1995 Late Show with David Letterman: Video Special Funniest Male Performer in a TV Series (Leading Role) Network, Cable or Syndication 1994 Late Show with David Letterman 2001 Late Show with David Letterman

David Michael Letterman (born April 12, 1947) is an American television host and comedian.^[1] He hosts the late night television talk show, Late Show with David Letterman, broadcast on CBS. Letterman has been a fixture on late night television since the 1982 debut of Late Night with David Letterman on NBC. Letterman recently surpassed friend and mentor Johnny Carson for having the longest late-night hosting career in the United States of America.^[4]

Letterman is also a television and film producer. His company Worldwide Pants produces his show as well as its network follow-up The Late Late Show with Craig Ferguson. Worldwide Pants has also produced several prime-time comedies, the most successful of which was Everybody Loves Raymond, currently in syndication.

In 1996, David Letterman was ranked #45 on TV Guide's 50 Greatest TV Stars of All Time.^[5]

Early life and career[link]

Letterman was born in Indianapolis, Indiana. His father, Harry Joseph Letterman (April 1915 – February 1973),^[6] was a florist of British descent; his mother Dorothy Letterman (née Hofert, now Dorothy Mengering), a Presbyterian church secretary of German descent, is an occasional figure on the show, usually at holidays and birthdays.

Letterman lived on the north side of Indianapolis (Broad Ripple area), not far from Speedway, IN, and the Indianapolis Motor Speedway, and he enjoyed collecting model cars, including racers.^[7] In 2000, he told an interviewer for Esquire that, while growing up, he admired his father's ability to tell jokes and be the life of the party. Harry Joseph Letterman survived a heart attack at age 36, when David was a young boy. The fear of losing his father was constantly with Letterman as he grew up.^[8] The elder Letterman died of a second heart attack^[9] at age 57.

Letterman attended his hometown's Broad Ripple High School at the same time as Marilyn Tucker (future wife of Dan Quayle) and worked as a stock boy at the local Atlas supermarket.^[10] According to the Ball State Daily News, he originally had wanted to attend Indiana University, but his grades weren't good enough, so he decided to attend Ball State University, in Muncie, Indiana.^[11] He is a member of the Sigma Chi Fraternity, and he graduated from what was then the Department of Radio and Television, in 1969. A self-described average student, Letterman endowed a scholarship for what he called "C students" at Ball State.^[12]

Though he registered for the draft and passed his physical after graduating from college, he was not drafted for service in Vietnam due to receiving a draft lottery number of 352 (out of 365).^[13]

Letterman began his broadcasting career as an announcer and newscaster at the college's student-run radio station—WBST—a 10-watt campus station which now is part of Indiana Public Radio.^[14] He was fired for treating classical music with irreverence.^[14]

Letterman then became involved with the founding of another campus station—WAGO-AM 570 (now WWHI, 91.3).^[15]

Letterman credits Paul Dixon—host of the Paul Dixon Show, a Cincinnati-based talk show also shown in Indianapolis while Letterman was growing up—for inspiring his choice of career:^[3]

"I was just out of college [in 1969], and I really didn't know what I wanted to do. And then all of a sudden I saw him doing it [on TV]. And I thought: That's really what I want to do!"

Weatherman[link]

Letterman began his career as a radio talk show host on WNTS (AM), and on Indianapolis television station WLWI (now called WTHR) as an anchor, and weatherman. He received some attention for his unpredictable on-air behavior, which included congratulating a tropical storm for being upgraded to a hurricane and predicting hail stones "the size of canned hams."^[16] He would also occasionally report the weather and the day's very high and low temps for fictitious cities ("Eight inches of snow in Bingree and surrounding areas.") while on another occasion saying that a state border had been erased.^[17] ("From space you can see the border between Indiana and Ohio has been erased. I'm not in favor of this.") He also starred in a local kiddie show, made wisecracks as host of a late night TV show called "Freeze-Dried Movies" (he once acted out a scene from "Godzilla" using plastic dinosaurs),^[18] and hosted a talk show that aired early on Saturday mornings called "Clover Power,"^[19] in which he interviewed 4-H members about their projects.^[20]

In 1971, Letterman appeared as a pit road reporter for ABC Sports' tape-delayed coverage of the Indianapolis 500.^[21] David initially is introduced as Chris Economaki in his job as a corner reporter. Letterman interviews Mario Andretti who has just crashed out of the race and asks him a question about traffic on the course.

Move to Los Angeles[link]

In 1975, encouraged by his then-wife Michelle and several of his Sigma Chi fraternity brothers, Letterman moved to Los Angeles, California, with hope of becoming a comedy writer.^[22] He started off by writing material for comedian Jimmie Walker.^[23] He also began performing stand-up comedy at The Comedy Store, a proving ground for unknown comics.

In the summer of 1977, Letterman was a writer and regular on the six-week summer series The Starland Vocal Band Show, broadcast on CBS.^[24] He hosted a 1977 pilot for a game show entitled The Riddlers^[25][26] that was never picked up and co-starred in the Barry Levinson-produced comedy special Peeping Times that aired in January 1978. Later that year, Letterman was a cast member on Mary Tyler Moore's variety show, Mary.^[27] Letterman made a guest appearance on Mork & Mindy (as a parody of EST leader Werner Erhard^[28]) and appearances on game shows such as The $20,000 Pyramid,^[29] The Gong Show, Password Plus^[30] and Liar's Club, as well as talk shows such as The Mike Douglas Show.^[31] He was also screen tested for the lead role in the 1980 film Airplane!, a role that eventually went to Robert Hays.^[32]

His dry, sarcastic humor caught the attention of scouts for The Tonight Show Starring Johnny Carson, and Letterman was soon a regular guest on the show. Letterman became a favorite of Carson's and was a regular guest host for the show beginning in 1978. Letterman credits Carson as the person who influenced his career the most.^[2]

NBC[link]

Letterman at the 38th Primetime Emmy Awards in 1986

Morning show[link]

On June 23, 1980, Letterman was given his own morning comedy show on NBC, The David Letterman Show. It was originally 90 minutes long, but was shortened to 60 minutes in August 1980.^[33] The show was a critical success, winning two Emmy Awards, but was a ratings disappointment and was canceled in October 1980.

[edit] Late Night with David Letterman