Blue light is scattered more than other wavelengths by the gases in the atmosphere, giving the Earth a blue halo when seen from space.

Limb view, of the Earth's atmosphere. Colours roughly denote the layers of the atmosphere.

This image shows the moon at centre, with the limb of Earth near the bottom transitioning into the orange-coloured troposphere, the lowest and most dense portion of the Earth's atmosphere. The troposphere ends abruptly at the tropopause, which appears in the image as the sharp boundary between the orange- and blue- coloured atmosphere. The silvery-blue noctilucent clouds extend far above the Earth's troposphere.

The atmosphere of Earth is a layer of gases surrounding the planet Earth that is retained by Earth's gravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night (the diurnal temperature variation).

Atmospheric stratification describes the structure of the atmosphere, dividing it into distinct layers, each with specific characteristics such as temperature or composition. The atmosphere has a mass of about 5×10¹⁸ kg, three quarters of which is within about 11 km (6.8 mi; 36,000 ft) of the surface. The atmosphere becomes thinner and thinner with increasing altitude, with no definite boundary between the atmosphere and outer space. An altitude of 120 km (75 mi) is where atmospheric effects become noticeable during atmospheric reentry of spacecraft. The Kármán line, at 100 km (62 mi), also is often regarded as the boundary between atmosphere and outer space.

Air is the name given to atmosphere used in breathing and photosynthesis. Dry air contains roughly (by volume) 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1%. While air content and atmospheric pressure vary at different layers, air suitable for the survival of terrestrial plants and terrestrial animals is currently only known to be found in Earth's troposphere and artificial atmospheres.

Composition[link]

Composition of Earth's atmosphere. The lower pie represents the trace gases which together compose 0.039% of the atmosphere. Values normalized for illustration. The numbers are from a variety of years (mainly 1987, with CO₂ and methane from 2009) and do not represent any single source.

Mean atmospheric water vapor

Air is mainly composed of nitrogen, oxygen, and argon, which together constitute the major gases of the atmosphere. The remaining gases are often referred to as trace gases,^[1] among which are the greenhouse gases such as water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Filtered air includes trace amounts of many other chemical compounds. Many natural substances may be present in tiny amounts in an unfiltered air sample, including dust, pollen and spores, sea spray, and volcanic ash. Various industrial pollutants also may be present, such as chlorine (elementary or in compounds), fluorine compounds, elemental mercury, and sulfur compounds such as sulfur dioxide [SO₂].

Structure of the atmosphere[link]

Principal layers[link]

In general, air pressure and density decrease in the atmosphere as height increases. However, temperature has a more complicated profile with altitude. Because the general pattern of this profile is constant and recognizable through means such as balloon soundings, temperature provides a useful metric to distinguish between atmospheric layers. In this way, Earth's atmosphere can be divided into five main layers. From highest to lowest, these layers are:

Exosphere[link]

The outermost layer of Earth's atmosphere extends from the exobase upward. It is mainly composed of hydrogen and helium. The particles are so far apart that they can travel hundreds of kilometers without colliding with one another. Since the particles rarely collide, the atmosphere no longer behaves like a fluid. These free-moving particles follow ballistic trajectories and may migrate into and out of the magnetosphere or the solar wind.

Thermosphere[link]

Temperature increases with height in the thermosphere from the mesopause up to the thermopause, then is constant with height. Unlike in the stratosphere, where the inversion is caused by absorption of radiation by ozone, in the thermosphere the inversion is a result of the extremely low density of molecules. The temperature of this layer can rise to 1,500 °C (2,700 °F), though the gas molecules are so far apart that temperature in the usual sense is not well defined. The air is so rarefied that an individual molecule (of oxygen, for example) travels an average of 1 kilometer between collisions with other molecules.^[3] The International Space Station orbits in this layer, between 320 and 380 km (200 and 240 mi). Because of the relative infrequency of molecular collisions, air above the mesopause is poorly mixed compared to air below. While the composition from the troposphere to the mesosphere is fairly constant, above a certain point, air is poorly mixed and becomes compositionally stratified. The point dividing these two regions is known as the turbopause. The region below is the homosphere, and the region above is the heterosphere. The top of the thermosphere is the bottom of the exosphere, called the exobase. Its height varies with solar activity and ranges from about 350–800 km (220–500 mi; 1,100,000–2,600,000 ft).^{[citation needed]}

Mesosphere[link]

The mesosphere extends from the stratopause to 80–85 km (50–53 mi; 260,000–280,000 ft). It is the layer where most meteors burn up upon entering the atmosphere. Temperature decreases with height in the mesosphere. The mesopause, the temperature minimum that marks the top of the mesosphere, is the coldest place on Earth and has an average temperature around −85 °C (−120 °F; 190 K).^[4] At the mesopause, temperatures may drop to −100 °C (−150 °F; 170 K).^[5] Due to the cold temperature of the mesosphere, water vapor is frozen, forming ice clouds (or Noctilucent clouds). A type of lightning referred to as either sprites or ELVES, form many miles above thunderclouds in the troposphere.

Stratosphere[link]

The stratosphere extends from the tropopause to about 51 km (32 mi; 170,000 ft). Temperature increases with height due to increased absorption of ultraviolet radiation by the ozone layer, which restricts turbulence and mixing. While the temperature may be −60 °C (−76 °F; 210 K) at the tropopause, the top of the stratosphere is much warmer, and may be near freezing^{[citation needed]}. The stratopause, which is the boundary between the stratosphere and mesosphere, typically is at 50 to 55 km (31 to 34 mi; 160,000 to 180,000 ft). The pressure here is 1/1000 sea level.

Troposphere[link]

The troposphere begins at the surface and extends to between 9 km (30,000 ft) at the poles and 17 km (56,000 ft) at the equator,^[6] with some variation due to weather. The troposphere is mostly heated by transfer of energy from the surface, so on average the lowest part of the troposphere is warmest and temperature decreases with altitude. This promotes vertical mixing (hence the origin of its name in the Greek word "τροπή", trope, meaning turn or overturn). The troposphere contains roughly 80% of the mass of the atmosphere.^[7] The tropopause is the boundary between the troposphere and stratosphere.

Other layers[link]

Within the five principal layers determined by temperature are several layers determined by other properties:

• The ozone layer is contained within the stratosphere. In this layer ozone concentrations are about 2 to 8 parts per million, which is much higher than in the lower atmosphere but still very small compared to the main components of the atmosphere. It is mainly located in the lower portion of the stratosphere from about 15–35 km (9.3–22 mi; 49,000–110,000 ft), though the thickness varies seasonally and geographically. About 90% of the ozone in our atmosphere is contained in the stratosphere.
• The ionosphere, the part of the atmosphere that is ionized by solar radiation, stretches from 50 to 1,000 km (31 to 620 mi; 160,000 to 3,300,000 ft) and typically overlaps both the exosphere and the thermosphere. It forms the inner edge of the magnetosphere. It has practical importance because it influences, for example, radio propagation on the Earth. It is responsible for auroras.
• The homosphere and heterosphere are defined by whether the atmospheric gases are well mixed. In the homosphere the chemical composition of the atmosphere does not depend on molecular weight because the gases are mixed by turbulence.^[8] The homosphere includes the troposphere, stratosphere, and mesosphere. Above the turbopause at about 100 km (62 mi; 330,000 ft) (essentially corresponding to the mesopause), the composition varies with altitude. This is because the distance that particles can move without colliding with one another is large compared with the size of motions that cause mixing. This allows the gases to stratify by molecular weight, with the heavier ones such as oxygen and nitrogen present only near the bottom of the heterosphere. The upper part of the heterosphere is composed almost completely of hydrogen, the lightest element.
• The planetary boundary layer is the part of the troposphere that is nearest the Earth's surface and is directly affected by it, mainly through turbulent diffusion. During the day the planetary boundary layer usually is well-mixed, while at night it becomes stably stratified with weak or intermittent mixing. The depth of the planetary boundary layer ranges from as little as about 100 m on clear, calm nights to 3000 m or more during the afternoon in dry regions.

The average temperature of the atmosphere at the surface of Earth is 14 °C (57 °F; 287 K)^[9] or 15 °C (59 °F; 288 K),^[10] depending on the reference.^{[11] [12][13]}

Physical properties[link]

Comparison of the 1962 US Standard Atmosphere graph of geometric altitude against air density, pressure, the speed of sound and temperature with approximate altitudes of various objects.^[14]

Pressure and thickness[link]

The average atmospheric pressure at sea level is about 1 atmosphere (atm) = 101.3 kPa (kilopascals) = 14.7 psi (pounds per square inch) = 760 torr = 29.92 inches of mercury (symbol Hg). Total atmospheric mass is 5.1480×10¹⁸ kg (1.135×10¹⁹ lb),^[15] about 2.5% less than would be inferred from the average sea level pressure and the Earth's area of 51007.2 megahectares, this portion being displaced by the Earth's mountainous terrain. Atmospheric pressure is the total weight of the air above unit area at the point where the pressure is measured. Thus air pressure varies with location and weather.

If the atmosphere had a uniform density, it would terminate abruptly at an altitude of 8.50 km (27,900 ft). It actually decreases exponentially with altitude, dropping by half every 5.6 km (18,000 ft) or by a factor of 1/e every 7.64 km (25,100 ft), the average scale height of the atmosphere below 70 km (43 mi; 230,000 ft). However, the atmosphere is more accurately modeled with a customized equation for each layer that takes gradients of temperature, molecular composition, solar radiation and gravity into account.

In summary, the mass of the earth's atmosphere is distributed approximately as follows:^[16]

• 50% is below 5.6 km (18,000 ft).
• 90% is below 16 km (52,000 ft).
• 99.99997% is below 100 km (62 mi; 330,000 ft), the Kármán line. By international convention, this marks the beginning of space where human travelers are considered astronauts.

By comparison, the summit of Mt. Everest is at 8,848 m (29,029 ft); commercial airliners typically cruise between 10 km (33,000 ft) and 13 km (43,000 ft) where the thinner air improves fuel economy; weather balloons reach 30.4 km (100,000 ft) and above; and the highest X-15 flight in 1963 reached 108.0 km (354,300 ft).

Even above the Kármán line, significant atmospheric effects such as auroras still occur. Meteors begin to glow in this region though the larger ones may not burn up until they penetrate more deeply. The various layers of the earth's ionosphere, important to HF radio propagation, begin below 100 km and extend beyond 500 km. By comparison, the International Space Station and Space Shuttle typically orbit at 350–400 km, within the F-layer of the ionosphere where they encounter enough atmospheric drag to require reboosts every few months. Depending on solar activity, satellites can still experience noticeable atmospheric drag at altitudes as high as 700–800 km.

Density and mass[link]

Temperature and mass density against altitude from the NRLMSISE-00 standard atmosphere model (the eight dotted lines in each "decade" are at the eight cubes 8, 27, 64, ..., 729)

The density of air at sea level is about 1.2  kg/m³ (1.2 g/L). Density is not measured directly but is calculated from measurements of temperature, pressure and humidity using the equation of state for air (a form of the ideal gas law). Atmospheric density decreases as the altitude increases. This variation can be approximately modeled using the barometric formula. More sophisticated models are used to predict orbital decay of satellites.

The average mass of the atmosphere is about 5 quadrillion (5×10¹⁵) tonnes or 1/1,200,000 the mass of Earth. According to the American National Center for Atmospheric Research, "The total mean mass of the atmosphere is 5.1480×10¹⁸ kg with an annual range due to water vapor of 1.2 or 1.5×10¹⁵ kg depending on whether surface pressure or water vapor data are used; somewhat smaller than the previous estimate. The mean mass of water vapor is estimated as 1.27×10¹⁶ kg and the dry air mass as 5.1352 ±0.0003×10¹⁸ kg."

Optical properties[link]

Solar radiation (or sunlight) is the energy the Earth receives from the Sun. The Earth also emits radiation back into space, but at longer wavelengths that we cannot see. Part of the incoming and emitted radiation is absorbed or reflected by the atmosphere.

Scattering[link]

When light passes through our atmosphere, photons interact with it through scattering. If the light does not interact with the atmosphere, it is called direct radiation and is what you see if you were to look directly at the Sun. Indirect radiation is light that has been scattered in the atmosphere. For example, on an overcast day when you cannot see your shadow there is no direct radiation reaching you, it has all been scattered. As another example, due to a phenomenon called Rayleigh scattering, shorter (blue) wavelengths scatter more easily than longer (red) wavelengths. This is why the sky looks blue; you are seeing scattered blue light. This is also why sunsets are red. Because the Sun is close to the horizon, the Sun's rays pass through more atmosphere than normal to reach your eye. Much of the blue light has been scattered out, leaving the red light in a sunset.

Absorption[link]

Different molecules absorb different wavelengths of radiation. For example, O₂ and O₃ absorb almost all wavelengths shorter than 300 nanometers. Water (H₂O) absorbs many wavelengths above 700 nm. When a molecule absorbs a photon, it increases the energy of the molecule. We can think of this as heating the atmosphere, but the atmosphere also cools by emitting radiation, as discussed below.

Rough plot of Earth's atmospheric transmittance (or opacity) to various wavelengths of electromagnetic radiation, including visible light.

The combined absorption spectra of the gases in the atmosphere leave "windows" of low opacity, allowing the transmission of only certain bands of light. The optical window runs from around 300 nm (ultraviolet-C) up into the range humans can see, the visible spectrum (commonly called light), at roughly 400–700 nm and continues to the infrared to around 1100 nm. There are also infrared and radio windows that transmit some infrared and radio waves at longer wavelengths. For example, the radio window runs from about one centimeter to about eleven-meter waves.

Emission[link]

Emission is the opposite of absorption, it is when an object emits radiation. Objects tend to emit amounts and wavelengths of radiation depending on their "black body" emission curves, therefore hotter objects tend to emit more radiation, with shorter wavelengths. Colder objects emit less radiation, with longer wavelengths. For example, the Sun is approximately 6,000 K (5,730 °C; 10,340 °F), its radiation peaks near 500 nm, and is visible to the human eye. The Earth is approximately 290 K (17 °C; 62 °F), so its radiation peaks near 10,000 nm, and is much too long to be visible to humans.

Because of its temperature, the atmosphere emits infrared radiation. For example, on clear nights the Earth's surface cools down faster than on cloudy nights. This is because clouds (H₂O) are strong absorbers and emitters of infrared radiation. This is also why it becomes colder at night at higher elevations. The atmosphere acts as a "blanket" to limit the amount of radiation the Earth loses into space.

The greenhouse effect is directly related to this absorption and emission (or "blanket") effect. Some chemicals in the atmosphere absorb and emit infrared radiation, but do not interact with sunlight in the visible spectrum. Common examples of these chemicals are CO₂ and H₂O. If there are too much of these greenhouse gases, sunlight heats the Earth's surface, but the gases block the infrared radiation from exiting back to space. This imbalance causes the Earth to warm, and thus climate change.

Refractive index[link]

The refractive index of air is close to, but just greater than 1. Systematic variations in refractive index can lead to the bending of light rays over long optical paths. One example is that, under some circumstances, observers onboard ships can see other vessels just over the horizon because light is refracted in the same direction as the curvature of the Earth's surface.

The refractive index of air depends on temperature, giving rise to refraction effects when the temperature gradient is large. An example of such effects is the mirage.

Circulation[link]

An idealised view of three large circulation cells.

Atmospheric circulation is the large-scale movement of air through the troposphere, and the means (with ocean circulation) by which heat is distributed around the Earth. The large-scale structure of the atmospheric circulation varies from year to year, but the basic structure remains fairly constant as it is determined by the Earth's rotation rate and the difference in solar radiation between the equator and poles.

Evolution of Earth's atmosphere[link]

Earliest atmosphere[link]

The outgassings of the Earth were stripped away by solar winds early in the history of the planet until a steady state was established, the first atmosphere. Based on today's volcanic evidence, this atmosphere would have contained 60% hydrogen, 20% oxygen (mostly in the form of water vapor), 10% carbon dioxide, 5 to 7% hydrogen sulfide, and smaller amounts of nitrogen, carbon monoxide, free hydrogen, methane and inert gases.^{[citation needed]}

A major rainfall led to the buildup of a vast ocean, enriching the other agents, first carbon dioxide and later nitrogen and inert gases. A major part of carbon dioxide exhalations were soon dissolved in water and built up carbonate sediments.

Second atmosphere[link]

Water-related sediments have been found dating from as early as 3.8 billion years ago.^[17] About 3.4 billion years ago, nitrogen was the major part of the then stable "second atmosphere". An influence of life has to be taken into account rather soon in the history of the atmosphere, since hints of early life forms are to be found as early as 3.5 billion years ago.^[18] The fact that this is not perfectly in line with the 30% lower solar radiance (compared to today) of the early Sun has been described as the "faint young Sun paradox".

The geological record however shows a continually relatively warm surface during the complete early temperature record of the Earth with the exception of one cold glacial phase about 2.4 billion years ago. In the late Archaean eon an oxygen-containing atmosphere began to develop, apparently from photosynthesizing algae which have been found as stromatolite fossils from 2.7 billion years ago. The early basic carbon isotopy (isotope ratio proportions) is very much in line with what is found today,^[19] suggesting that the fundamental features of the carbon cycle were established as early as 4 billion years ago.

Third atmosphere[link]

Oxygen content of the atmosphere over the last billion years. This diagram in more detail

The accretion of continents about 3.5 billion years ago^[20] added plate tectonics, constantly rearranging the continents and also shaping long-term climate evolution by allowing the transfer of carbon dioxide to large land-based carbonate storages. Free oxygen did not exist until about 1.7 billion years ago and this can be seen with the development of the red beds and the end of the banded iron formations. The Earth had a lot of iron in the beginning, and higher amounts of oxygen was not available in the atmosphere until all the iron had ben oxidized. This signifies a shift from a reducing atmosphere to an oxidising atmosphere. O₂ showed major ups and downs until reaching a steady state of more than 15%.^[21] The following time span was the Phanerozoic eon, during which oxygen-breathing metazoan life forms began to appear.

The amount of oxygen in the atmosphere has gone up and down during the last 600 million years. There was a peak 280 million years ago, when the amount of oxygen was about 30 %, much higher than today. The cause of changes in the atmosphere is two main processes: Plants converts carbon dioxide into the bodies of the plants, which emits oxygen into the atmosphere, and break down of pyrite rocks cause sulphur to be added to the oceans. Volcanos cause this sulphur to be oxidized, reducing the amount of oxygen in the atmosphere. But volcanos also emit carbon dioxide, so that plants can convert this to oxygen. The exact cause of the variation of oxygen in the atmosphere is not known. Periods with much oxygen in the atmosphere are believed to cause rapid development of animals. Even if the atmosphere today has only 21 percent oxygen, today is still regarded as a period with rapid development of animals because of a high amount of oxygen in the atmosphere.^[22]

Currently, anthropogenic greenhouse gases are increasing in the atmosphere. According to the Intergovernmental Panel on Climate Change, this increase is the main cause of global warming.^[23]

Air pollution[link]

Air pollution is the introduction of chemicals, particulate matter, or biological materials that cause harm or discomfort to organisms into the atmosphere.^[24] Stratospheric ozone depletion is believed to be caused by air pollution (chiefly from chlorofluorocarbons).^{[citation needed]}

See also[link]

	Atmosphere portal
	Environment portal

References[link]

External links[link]

Wikimedia Commons has media related to: Earth's atmosphere

• NASA atmosphere models
• NASA's Earth Fact Sheet
• American Geophysical Union: Atmospheric Sciences
• Outreach of the GEOmon project See how Earth atmosphere is observed and monitored by a European project that combines many approaches.
• Stuff in the Air Find out what the atmosphere contains.
• Layers of the Atmosphere
• Answers to several questions of curious kids related to Air and Atmosphere
• The AMS Glossary of Meteorology
• Paul Crutzen Interview Free video of Paul Crutzen Nobel Laureate for his work on decomposition of ozone talking to Harry Kroto Nobel Laureate by the Vega Science Trust.
• Slides describing the Earth's modern atmosphere

v t e Atmospheres Major Sun Venus Earth Mars Jupiter Saturn Titan Uranus Neptune Triton Pluto HD 209458 b Tenuous Mercury Moon Io Europa Ganymede Callisto Enceladus Dione Rhea See also Stellar atmosphere Coma (cometary) Extraterrestrial atmospheres

Bill Nye
Nye at Bridgewater State University in 2007
Born	(1955-11-27) November 27, 1955 (age 56)[1] Washington, D.C.[1]
Residence	Los Angeles
Fields	Mechanical engineering
Institutions	Boeing Cornell University Planetary Society
Alma mater	Cornell University (BS)
Known for	Bill Nye the Science Guy
Signature

William Sanford "Bill" Nye (born November 27, 1955),^[2] popularly known as Bill Nye the Science Guy, is an American science educator, comedian, television host, actor, mechanical engineer, and scientist. He is best known as the host of the Disney/PBS children's science show Bill Nye the Science Guy (1993–1998) and for his many subsequent appearances in popular media as a science educator.

Early life and career[link]

William Sanford Nye was born in Washington, D.C., the son of Jacqueline (née Jenkins; c. 1920–2000), a codebreaker during World War II, and Edwin Darby "Ned" Nye (died 1997), also a World War II veteran whose experience in a Japanese prisoner of war camp led him to become a sundial enthusiast.^[3][4][5] Nye is a fourth-generation Washington, D.C. resident on his father's side of the family. After attending Lafayette Elementary and Alice Deal Junior High in the city, he was accepted to the private Sidwell Friends School on a partial scholarship, graduating in 1973.^[6][7] He studied mechanical engineering at Cornell University, where one of his professors was Carl Sagan,^[8] and graduated with a Bachelor of Science in 1977.^[9] He was awarded an honorary doctorate by The Johns Hopkins University in May 2008. In May 2011, Nye was awarded an Honorary Doctor of Science degree from Willamette University where he was the keynote speaker for that year's commencement exercises.^[10]

Nye began his career in Seattle at Boeing, where, among other things, he starred in training films and developed a hydraulic pressure resonance suppressor still used in the 747. Later he worked as a consultant in the aeronautics industry. Nye told the St. Petersburg Times in 1999 that he applied to be a NASA astronaut every few years but was always rejected.^[11]

The Science Guy[link]

Nye began his professional entertainment career as an actor on a local sketch comedy television show in Seattle, Almost Live!; Nye attempted to correct the host of Almost Live! after the host pronounced "gigawatt" as "jigowatt."^[12][13] The character name came from the host's comment "Who do you think you are—Bill Nye the Science Guy?" and Nye was thereafter known as such on the program. His other main recurring role on Almost Live! was as Speedwalker, a speedwalking Seattle superhero.

Coincidentally, in 1991–93 he appeared in the live-action educational segments of Back to the Future: The Animated Series with a nonspeaking role as an assistant to Dr. Emmett Brown, played by Christopher Lloyd, in which he would demonstrate science with Lloyd's voice-over. The segments' national popularity led to Nye's hosting the educational television program Bill Nye the Science Guy from 1993 to 1998. Each of the 100 episodes aimed to teach a specific topic in science to a preteen audience, yet it garnered a wide adult audience as well. The show was very popular as a school resource and is still used to this day. He has written several books as The Science Guy. In addition to hosting the show, he was also a writer and producer for the series, which was filmed entirely in Seattle.

When portraying "the Science Guy", Nye wears a light blue lab coat and a bow tie and takes on the persona of an excited, jocular science educator. This popular image of Nye has been parodied by numerous sources, including the webcomic xkcd^[14] and the satirical news organization The Onion.^[15][16] In response to the fake headline "Crack Nearly Killed Me," Nye took the joke in good humor and sent The Onion an email thanking them for "dealing compassionately with this matter."^[17]

He appeared in his Science Guy persona alongside Ellen DeGeneres and Alex Trebek in Ellen's Energy Adventure, an attraction that has played since 1996 at the Universe of Energy pavilion inside Epcot at Walt Disney World. He also has a voice-over at the DINOSAUR attraction in Disney's Animal Kingdom park, where he tells guests about the dinosaurs while they queue for the ride. In addition, he appears in the "Design Lab" of CyberSpace Mountain inside DisneyQuest at Walt Disney World, where he refers to himself as "Bill Nye the Coaster Guy."

[edit] Post-Science Guy career

This article is in a list format that may be better presented using prose. You can help by converting this article to prose, if appropriate. Editing help is available. (May 2010)

Bill Nye "The Science Guy" and Executive Director of The Planetary Society received the Committee for Skeptical Inquiry's "In Praise of Reason" Award at CSICON 2011 in New Orleans

Nye remained interested in science education through entertainment. He created a 13-episode PBS KCTS-TV series about science, called The Eyes of Nye, aimed at an older audience than his previous show had been. Airing in 2005, it often featured episodes based on politically relevant themes such as genetically modified food, global warming, and race.

He played a science teacher in Disney's 1998 TV movie The Principal Takes a Holiday; he made a hovercraft in order to demonstrate science in an unusual classroom manner. From 2000 to 2002, Nye was the technical expert in BattleBots. In 2004 and 2005, Nye hosted 100 Greatest Discoveries, an award-winning series produced by THINKFilm for The Science Channel and in high definition on the Discovery HD Theater. He was also host of an eight-part Discovery Channel series called Greatest Inventions with Bill Nye.

Nye has guest-starred in several episodes of the crime drama Numb3rs as an engineering faculty member. A lecture Nye gave several years ago on exciting children about math was an inspiration for creating the Numb3rs show.^[18]

Bill joined the American Optometric Association in a multimedia advertising campaign to educate parents on the importance of getting their children a comprehensive eye examination.^[19]

He was a regular in TV Land discussions. He has also made guest appearances on the VH1 reality show America's Most Smartest Model.^[20]

Nye appears in segments of The Climate Code on The Weather Channel, telling his personal ways of saving energy. He still makes regular appearances on the show, often asking quiz questions.

As of fall 2008, Nye also appears on the daytime game show Who Wants to Be a Millionaire as part of the show's reintroduced "Ask the Expert" lifeline. In 2008, he also hosted Stuff Happens, a show on the then new Planet Green network.

In November 2008, Nye appeared in an acting role as himself in the fifth-season episode "Brain Storm" of Stargate Atlantis alongside fellow television personality and astrophysicist Neil deGrasse Tyson.^[21]

Nye has appeared numerous times on the talk show Larry King Live, speaking about topics such as global warming^[22] and UFOs.^[23] He argued that global warming is an issue that should be addressed by governments of the world in part because it could be implicated in the record-setting 2005 Atlantic hurricane season. On UFOs he has been skeptical of extraterrestrial explanations for sightings such as those at Roswell and Malmstrom Air Force Base in 1967.

In 2009, portions of Bill Nye's shows were used as lyrics and portions of the second Symphony of Science science education music video by composer John Boswell.

Nye recorded a short YouTube video (as himself, not his TV persona) advocating clean energy climate change legislation on behalf of Al Gore's Repower America campaign in October 2009.^[24]

Nye (as his TV persona) also made a guest appearance on The Dr. Oz Show.

On March 12, 2011, Nye made an appearance on CNN to discuss the evolving nuclear incidents in Japan as a result of the devastating earthquake and tsunami there. Nye erroneously stated that cesium is used to "slow and control" the nuclear reaction. ^[25] In reality, cesium (specifically cesium-137) is a nuclear fission product, not a control rod material. Nye also erroneously stated that the nuclear reactor involved in the Three Mile Island incident is still running and that the use of boron to slow the nuclear chain reaction is uncommon, when in fact boron-10 is commonly used in control rods, and is circulated in the coolant of reactors in the United States, as well as stored on site as a method of emergency shutdown.^[26][27]

A solar noon clock atop Rhodes Hall was gifted from Nye to Cornell on Aug. 27 following a public lecture that filled the 715-seat Statler Auditorium. Nye talked about his father's passion for sundials and timekeeping, his time at Cornell, his work on the sundials mounted on the Mars rovers and the story behind the Bill Nye Solar Noon Clock. ^[28]

Life outside television[link]

Nye speaking in 2010.

In the early 2000s, Nye assisted in the development of a small sundial that was included in the Mars Exploration Rover missions. Known as MarsDial, it included small colored panels to provide a basis for color calibration in addition to helping keep track of time.^[29] From 2005 to 2010 Nye was the vice president of The Planetary Society, an organization that advocates space science research and the exploration of other planets, particularly Mars.^[30] He became the organization's second Executive Director in September 2010 when Louis Friedman stepped down.^[31][32]

In November 2010, Nye became the face of a new permanent exhibition at the Chabot Space & Science Center in Oakland, CA. Bill Nye’s Climate Lab features Nye as commander of the Clean Energy Space Station, and invites visitors on an urgent mission to thwart climate change. Beginning with a view of Planet Earth from space, visitors explore air, water, and land galleries to discover how climate change affects Earth’s connected systems, and how to use the Sun, wind, land, and water to generate clean energy. In an interview about the exhibit, Nye said, “Everything in the exhibit is geared to showing you that the size of the problem of climate change is big. Showing you a lot about energy use... It’s a huge opportunity... We need young people, entrepreneurs, young inventors, young innovators to change the world.” ^[33]

He holds several United States patents,^[34] including one for ballet pointe shoes^[30] and another for an educational magnifying glass created by filling a clear plastic bag with water.^[35][36] From 2001–2006 Nye served as Frank H.T. Rhodes Class of '56 University Professor at Cornell University.^[9][37] Nye supported the 2006 reclassification of Pluto from a planet to a dwarf planet by the International Astronomical Union.^[38]

Since 2006, Nye has lived in Los Angeles in a house with modifications, though has owned a house on Mercer Island.^{[citation needed]} As of July 2007, Nye and environmental activist Ed Begley, Jr. are engaging in a friendly competition "to see who could have the lowest carbon footprint," according to Begley.^[39] In a 2008 interview, Nye joked that he wants to "crush Ed Begley" in their environmental competition.^[40] Nye and Begley are neighbors in Los Angeles, and sometimes dine together at a local vegetarian restaurant.^[40] Nye often appears on Begley's Planet Green reality show Living with Ed.

Nye made an appearance in Palmdale's 2010 video "Here Comes the Summer"^[41]; the band's lead singer Kay Hanley is his neighbor.

Nye is a fellow of the Committee for Skeptical Inquiry, a U.S. non-profit scientific and educational organization whose aim is to promote scientific inquiry, critical investigation, and the use of reason in examining controversial and extraordinary claims.^[42]

Interviewed by John Rael for the Independent Investigation Group IIG, Nye stated that his "concern right now... scientific illiteracy... you don't [the public] have enough rudimentary knowledge of the universe to evaluate claims."^[43]

Personal life[link]

Nye announced his engagement during an appearance on The Late Late Show with Craig Ferguson and was married briefly to his fiancée of five months, author Blair Tindall, on February 3, 2006. The ceremony was performed by Rick Warren at The Entertainment Gathering at the Skirball Cultural Center in Los Angeles. Yo-Yo Ma provided the music.^[44] Nye left the relationship seven weeks later when the marriage license was declared invalid;^[45] their impromptu ceremony, which preceded the license purchase, violated California state law, said Tindall in a radio interview.^[46] Nye later secured a temporary restraining order against Tindall after she entered his property late at night to pour weed killer in his garden.^[45]

Nye enjoys baseball and occasionally does experiments involving the physics of the game. As a longtime Seattle resident before becoming an entertainer, he is said to have been a fan of the Seattle Mariners, although recently he has voiced his preference (as a D.C. native) for the Washington Nationals.^[6]

References[link]

External links[link]

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Biography portal

Wikimedia Commons has media related to: Bill Nye

• Official website
• Bill Nye at the Internet Movie Database
• Bill Nye on Twitter
• Nye-Tindall wedding video
• An interview/discussion with Nye as guest on the radio show Loveline
• "Changing The World With Science Education" interview on Point of Inquiry.
• Seattle Times interview (April 26, 2004)
• Science Channel interview