[person - cosmology, planetary science, space exploration, stellar and galactic astronomy] Welsh astronomer, born near Launceston, Cornwall (1819-1892). He successfully predicted the existence of a then-unknown planet (Neptune) based on perturbations in Uranus' orbit. He also studied the Leonid meteor shower, successfully predicting its occurrence and proving its association with Tempel's Comet.

• Appears in modules:

• Gravity

[noun - planetary science, evolution & adaptation, organisms] The branch of biology concerned with the search for life forms native to worlds other than Earth and with the origin, distribution, and evolution of life throughout the cosmos.

• Appears in modules:

• France Anne-Dominic Córdova
• Origins of Life I

[noun - astrophysics, cosmology, planetary science, scientific concepts] A theory proposed by Georges Lemaitre (originally known as the "hypothesis of the primeval atom") describing the origin of the universe. It was based on the idea that if the space between galaxy clusters is continuing to increase, then there had to be a time when these same bodies were closer together. The term "Big Bang" was coined by Fred Hoyle in 1949 to describe an event 13.7 million years ago involving the rapid expansion of matter and energy from a single hot, dense point. This expansion and cooling provided a foundation for the creation of the Universe.

[noun - astrophysics, stellar and galactic astronomy] A term coined by Sir William Herschel in 1802 to describe a pair of stars that revolve around a common mass and are unaffected by the mass of other stars, creating their own system.

• Appears in modules:

• The Nature of Scientific Knowledge

[noun - stellar and galactic astronomy, scientific concepts] Occurs when the observed light from an object appears to be of a shorter wavelength (bluer) than what is actually emitted. Blueshift is caused by the Doppler Effect, when a source of light moves toward an observer. See also redshift.

[person - planetary science] Danish astronomer, born in Knutstorp Castle (1546-1601). He is famous for his geocentric theory of the solar system, as well as for his meticulous astronomical observations concerning the positions of planets. He made his observations over 20 years, from the island of Hven. He later was appointed Imperial Mathematician to the Holy Roman Emperor, Rudolph II, in Prague.

• Appears in modules:

• Gravity
• Introduction to Descriptive Statistics

[noun - cosmology] (CMBR) a faint thermal radiation that exists in all of space. Theorized to be residual energy resulting from the Big Bang, this energy fills the Universe almost uniformly.

• Appears in modules:

• The Nature of Scientific Knowledge

[person - planetary science, research tools, solar and lunar processes, laws & theories, scientific tools & techniques, research methods, science & decision making, scientific concepts] The Italian physicist, mathematician, and astronomer born in Pisa in the Grand Duchy of Tuscany (1564-1642 CE). Among other things, Galileo studied the acceleration of objects and discovered the four largest moons of the planet Jupiter. His work significantly advanced the use of quantitative experimentation in science, and he made noteworthy contributions in the development of technology: He invented the refracting telescope, perfected the compound microscope, and improved compass design. Galileo was famously jailed during the Inquisition for his support of Copernicus's heliocentric view of the cosmos.

• Appears in modules:

• Factors that Control Regional Climate
• Gravity
• Scientific Institutions and Societies
• Temperature
• The Practice of Science
• Utilizing the Scientific Literature
• Water
• Waves and Wave Motion

[person - cosmology, planetary science] English astronomer born in Derbyshire (1656-1742). He observed transits of Mars and Venus to determine the distance from the Earth to the Sun, and accurately predicted the return of a comet, now named after him.

• Appears in modules:

• Gravity
• Utilizing the Scientific Literature

[person - cosmology] British cosmologist and theoretical physicist, born in Oxford (1942-). His most important contributions to science have been his study of quantum gravity and black holes. He also authored the extremely popular A Brief History of Time, which spent 237 weeks on the British Sunday Times best-seller list. Hawking suffers from amyotrophic lateral sclerosis (ALS), a degenerative motor neural disease also known as Lou Gehrig's disease, which was diagnosed during his graduate studies. He is confined to a wheelchair and speaks through a voice-box. As part of an ongoing effort to popularize science and space-travel, Hawking went on a sub-orbital flight, during which he became the first quadriplegic to experience antigravity.

• Appears in modules:

• Peer Review in Scientific Publishing
• Scientific Institutions and Societies

[adjective - planetary science] Having or representing the sun as a center, as in the heliocentric concept of the universe. Compare to geocentric.

• Appears in modules:

• Factors that Control Regional Climate
• The Practice of Science

[person - stellar and galactic astronomy] Scottish astronomer born in Slough (1792-1871). Herschel studied double star systems, made a comprehensive map of the celestial Southern hemisphere, and was a pioneer and strong proponent of the use of photography in astronomy, now a staple of astronomical research. His book Outlines of Astronomy was a standard textbook for decades after its publication, and the modern New General Catalog (the best-known catalogue of deep sky objects in amateur astronomy) is derived largely from his General Catalogue of Nebulae and Clusters.

• Appears in modules:

• Using Graphs and Visual Data in Science

[person - planetary science, stellar and galactic astronomy] English astronomer and composer born in Hanover, Germany (1738-1822). Herschel worked closely with his sister, Caroline. Their most important contribution was the discovery, in 1781, of the planet Uranus. They also discovered two moons of Uranus in 1787, and two of Saturn's moons. William Herschel's work on double stars showed that gravity acts outside of the solar system. He also studied sunspots and their connection to weather.

[person - astrophysics] Greek astronomer, mathematician, and geographer born in Nicaea (ca. 190-120 BCE). Hipparchus made the oldest surviving quantitative and accurate models for the motion of the Sun and Moon. He also developed a method for accurately predicting solar eclipses and compiled the first comprehensive star catalogue of the western celestial hemisphere.

• Appears in modules:

• Description in Scientific Research
• Wave Mathematics

[noun - planetary science, stellar and galactic astronomy] (H₀) a numerical value of the expansion factor of the universe. In 1929, Hubble identified this value as 500 km/sec/Mpc (kilometers per second per megaparsec). Today, this value has been refined (as a result of extensive research) to range from 45-90 km/sec/Mpc.

• Appears in modules:

• The Nature of Scientific Knowledge

[person - planetary science, stellar and galactic astronomy] Astronomer, born in Missouri, United States (1889-1953). Author of The Observational Approach to Cosmology and The Realm of the Nebulae (1935). Hubble was the first individual to demonstrate the existence of galaxies outside of our own. He also used Vesto Slipher's redshift data to show that the degree of redshift increases with distance, thus providing evidence that the universe is expanding. He discovered the asteroid 1373 Cincinnati.

• Appears in modules:

• The Nature of Scientific Knowledge

[noun - planetary science, solar and lunar processes, atmospheric science, weather & climate, energy resources, weather & climate] The output of electromagnetic energy from the sun as measured on Earth. Solar insolation is often measured as watts per meter squared or W/m². Humans perceive this energy as sunlight.

• Appears in modules:

• Factors that Control Earth's Temperature
• Factors that Control Regional Climate

[person - planetary science] German mathematician and astronomer born in Weil der Stadt, Württemburg (now part of Stuttgart, Germany) (1571-1630). Kepler is best known for outlining his laws of planetary motion, which defined the paths of the planets as orbits that could be mathematically represented as an ellipse. He was a champion of the Copernican model of the universe, publishing the Mysterium Cosmographicum in defense of it.

• Appears in modules:

• Gravity
• The Practice of Science

[person - research tools, fundamental constants] French mathematician and astronomer born in Normandy, France (1749-1827). Laplace made significant contributions in mathematics and error quantification and is credited with founding the field of mathematical astronomy. In addition, he predicted the existence of black holes and the concept of gravitational collapse.

• Appears in modules:

• Introduction to Descriptive Statistics
• Uncertainty, Error, and Confidence

[person - planetary science] French astronomer, born in Saint-Lô, (1811-1877). He worked primarily on celestial mechanics and, like John Couch Adams, predicted the existence of Neptune based on perturbations in the orbit of Uranus. He also, incorrectly, predicted the existence of a planet inside the orbit of Mercury, which he named Vulcan, based on perturbations in Mercury's orbit.

• Appears in modules:

• Gravity

[adjective - stellar and galactic astronomy, atmospheric science, rocks & minerals, weather & climate] Shaped like a lens, of or related to a lens; often referring to clouds, galaxies, rock bodies, or small features within rocks.

[noun - planetary science, solar and lunar processes] A celestial event occurring when the moon passes through some portion of Earth's shadow. This only occurs when the sun, Earth, and moon are aligned so that Earth is between the sun and moon.

• Appears in modules:

• Description in Scientific Research
• The Nature of Scientific Knowledge
• Utilizing the Scientific Literature

[noun - astrophysics, units of measurement] (Mpc) A numerical value of distance in space. 1 Mpc = 1 million paresecs, where one parsec equals 3.26 light years, or ~19 trillion miles.

[person - stellar and galactic astronomy, light & optics] American physicist, born in Strelno, Prussia (1852-1931). He is remembered for his work in optics, particularly for his early, extremely accurate experiments to determine the velocity of light. Michelson invented the interferometer, which he used to determine the effect of Earth's motion on the observed velocity of light. He was also interested in astronomy, and, using his interferometer, accurately measured the diameter of the star Betelgeuse. He was awarded a Nobel Prize in physics in 1907.

• Appears in modules:

• Light and Electromagnetism

[acronym - planetary science, space exploration] The National Aeronautics and Space Administration, a US government office established in 1958 to research flight in the Earth's atmosphere and beyond.

• Appears in modules:

• Confidence Intervals
• Description in Scientific Research
• Ellen Ochoa
• Factors that Control Earth's Temperature
• France Anne-Dominic Córdova
• Franklin Chang Díaz
• History of Earth's Atmosphere I
• Kevin Arrigo
• Origins of Life II
• Scientific Institutions and Societies
• The How and Why of Scientific Meetings
• The Practice of Science
• Unit Conversion

[noun - stellar and galactic astronomy] A nebula (singular) is a cloud of interstellar matter, mainly dust and gases. Nebulae (plural) are numerous nebula that form a cluster, such as a galaxy. Nebulae are the birthplace of stars, with rare exceptions.

• Appears in modules:

• History of Earth's Atmosphere I
• The Nature of Scientific Knowledge

[noun - forces, stellar and galactic astronomy, forces, modern physics] Occurs when the observed light from an object appears to be of a longer wavelength (redder) than what is actually emitted. Redshift may be caused by the Doppler Effect, when emitting source of light moves away from an observer. Cosmological redshift, by comparison, is caused by the stretching of space in which light rays travel due to the expansion of the universe. See also blueshift.

• Appears in modules:

• The Nature of Scientific Knowledge

[person] American astronomer and astrochemist, born in Brooklyn, New York (1934-1996). Sagan was a pioneer in astrobiology, and championed the Search for Extra-Terrestrial Intelligence (SETI). He was also a prolific researcher: He was key in the determination of Venus's high surface temperature, was an early proponent of oceans on Titan and Europa, and studied planetary atmospheres. He is best remembered for hosting the TV series Cosmos and for writing a widely popular companion book by the same name.

• Appears in modules:

• Origins of Life I
• Peer Review in Scientific Publishing

[person - planetary science, cosmology] Astronomer, born in Indiana, United States (1875-1969). Slipher was responsible for the discoveries of both galactic redshifts and the sodium layer, as well as involved in the work that led to the discovery of Pluto. Slipher's measurement of redshifts in spiral nebulae provided early evidence in support of the Big Bang Theory.

[noun - solar and lunar processes] A celestial event occurring when the Moon passes between the Sun and the Earth such that the Sun is wholly or partially obscured. At least two and up to five solar eclipses occur each year on Earth, with between zero and two of them being total eclipses.

• Appears in modules:

• Description in Scientific Research

[noun - space exploration] A journey to space by a spacecraft for a particular purpose, such as to collect scientific data.

• Appears in modules:

• Franklin Chang Díaz

[noun - space exploration] A spacecraft that carries people and cargo between Earth and outer space.

• Appears in modules:

• Ellen Ochoa
• Franklin Chang Díaz
• Modeling in Scientific Research

[noun] A visual image of how the spectrum of a wave signal changes over time. Spectrograms have applications in seismology, ornithology, phonetics, and many other disciplines dealing with waves.

• Appears in modules:

• The Nature of Scientific Knowledge

[noun - research tools] An instrument that measures the intensity of radiation, including light, as a function of its wavelength. Because different substances, including elements and compounds, both absorb and emit specific wavelengths of radiation, spectrometers can be used to measure the composition of distant stars and planets, as well as the composition of various samples on earth including soil, water, minerals, and gases.

• Appears in modules:

• Description in Scientific Research
• History of Earth's Atmosphere I
• Properties of Minerals

[noun - stellar and galactic astronomy] (or spiral galaxy) A galaxy that has a spiral structure, such as the Milky Way. The older stars are concentrated toward the center of spiral nebulae, while younger stars occupy the spiral's arms.

[adjective - planetary science, hydrology & fresh water, landforms & geologic formations, natural resources, nutrient cycles] In Environmental Science: related to, located on, or living on land. Not aquatic.

In Astronomy: related to or occurring on Earth. Not extraterrestrial (from space).

• Appears in modules:

• Biodiversity I
• Charles Darwin I
• Defining Minerals
• DNA II
• Energy
• Factors that Control Earth's Temperature
• Factors that Control Regional Climate
• France Anne-Dominic Córdova
• History of Earth's Atmosphere I
• History of Earth's Atmosphere II
• Photosynthesis I
• Properties of Minerals
• The Carbon Cycle
• The Hydrologic Cycle
• The Nitrogen Cycle
• The Rock Cycle
• The Silicate Minerals
• Theories, Hypotheses, and Laws
• Uncertainty, Error, and Confidence

[person] Italian mathematician and astronomer, born in Faenza, Italy (1608-1647). He authored Torricelli's Theorem, which states that the flow of liquid through an opening is proportional to the square root of the height of the liquid. Torricelli also experimentally proved that air has weight and invented the barometer. His work is somewhat obscure today, in part because he only published one work, Opera Geometrica.

• Appears in modules:

• Composition of Earth's Atmosphere
• Early Ideas about Matter
• Kinetic-Molecular Theory
• Properties of Gases

[noun - cosmology] The cosmos and everything that exists in it.

• Appears in modules:

• Atomic Theory III
• Charles Darwin I
• Chemical Equations
• Composition of Earth's Atmosphere
• Description in Scientific Research
• Diffusion I
• Early Ideas about Matter
• Energy
• Factors that Control Regional Climate
• France Anne-Dominic Córdova
• Gravity
• History of Earth's Atmosphere I
• History of Earth's Atmosphere II
• Light and Electromagnetism
• Light I
• Luis Walter Alvarez
• Mario Molina
• Peer Review in Scientific Publishing
• States of Matter
• The Carbon Cycle
• The How and Why of Scientific Meetings
• The Nature of Scientific Knowledge
• The Practice of Science
• The Process of Science

[person] An English scientist (1632-1723) appointed as the Gresham Professor of Astronomy at Cambridge at the young age of 25. Wren was instrumental in the establishment of the Royal Society of London as one of the first scientific institutions and also made his name as an architect, particularly in the renovation of historic buildings in London after the Great Fire of 1666.

• Appears in modules:

• Scientific Institutions and Societies