Flashcards in The Sun, Our Solar System, and Earth Deck (39):
What is the asteroid belt and where is it located?
The region of the solar system in which most asteroids have their orbits, between Mars and Jupiter
What is the chromosphere?
A region of the solar atmosphere between the bright photosphere and the more extensive corona. Hard to observe because of its relative faintness.
What is the corona?
The outer (high-temperature) region of the solar atmosphere.
What is a solar flare?
Rapid release of energy from a small region of the solar surface, observed as a sudden and localized brightening. Solar flares can emit cosmic rays as well as electromagnetic radiation.
What does granulation mean?
Terrazzo-like appearance of solar photosphere when observed at high magnification.
What is the heliocentric model and who invented it?
With the Sun at the center, as in the Copernican model for the solar system.
What is the Oort cloud and where is it located?
Suggested reservoir of comets, located in a spherical region around the Sun and about 50,000 AU in radius
What is the photosphere?
Bright apparent surface of a star from which most of the radiant energy is emitted. Not a solid surface but rather a region within the stellar (or solar) atmosphere
What is a sunspot?
Area that appears dark on the solar disc because the sunspot has a temperature somewhat lower than its surroundings.
What is the sunspot cycle?
11-year periodicity in the number of sunspots
What are the terresterial planets?
Mercury, Venus, Earth, and Mars
What are the Van Allen belts?
Regions around the Earth where the Earth?s magnetic field confines high-speed electrically charged particles, mostly protons and electrons.
What is the aphelion?
In a noncircular orbit around the sun, the aphelion is the position where a planet is farthest from the sun. For a noncircular orbit around the Earth, the apogee is the position where a satellite is farthest from the Earth.
What is an aroura?
Light emitted in the upper atmosphere in the far northern and southern latitudes. Produced by collisions of high-speed particles with atmospheric atoms and molecules, and strongly influenced by the Earth's magnetic field and solar activity.
What is the celestial equator?
Great circle formed on the celestial sphere by the extension out of the Earth's equatorial plane
What is the celestial sphere?
Apparent spherical surface, centered on the Earth to which the stars seem to be fixed.
What is the core of a planet?
Central region of a planet. The Earth?s core is liquid, possible with a small, solid inner core.
What is elongation?
Angle between the directions of a planet and the Sun, as viewed from the Earth.
How often do equinoxes occur and what are they?
Two days each year when the Sun is above and below the horizon for equal lengths of time.
What is the gegenschian?
Dim and hazy glow in the sky, seen in the direction opposite to the Sun, probably caused by sunlight reflected from many small dust particles.
What is Earth's ionosphere?
Outer region of the Earth's atmosphere where many of the atoms have been ionized by the absorption of solar ultraviolet radiation.
What are the Jovian planets in our solar system?
Jupiter, Saturn Uranus, and Neptune
What is the meridian?
Great circle, on the celestial sphere or the Earth, that passes through both north and south poles and an observer's zenith or location.
What is the nadir?
The point opposite the zenith on the celestial sphere.
What is the perigee?
Point in an Earth satellite?s orbit where it is closest to the center of the Earth.
What is the perihelion?
Place in an orbit around the Sun which is closest to the center of the Sun. A term most frequently encountered in describing cometary orbits.
What is a solstice?
Extreme positions reached by the Sun, north and south of the celestial equator. When the Sun is at these positions, the shadows it casts on the Earth?s surface are the longest or shortest (depending on whether you are making this observation in the northern or southern hemisphere).
What is the stratosphere and where is it located?
One of the upper layers of the Earth?s atmosphere, above the troposphere that contains most of the weather, and below the ionosphere
What does ecliptic mean in relation to the Sun and Stars?
Path that the Sun appears to follow, against the stars on the celestial sphere, during the course of a year.
What is the ecliptic plane pertaining to the Earth and the Sun?
Plane defined by the Earth?s orbit around the Sun
What is a limb? (as viewed from earth)
Edge of a bright object (Sun or planet) as viewed from Earth.
What is the summer solstice?
Extreme northern position of the Sun on the celestial sphere, north of the celestial equator (summer refers to the northern hemisphere).
What is the synodic period?
Time interval between successive repetitions of the same apparent positions of the Sun, Earth, and a body. Thus synodic period for a planet, or synodic month for the Moon.
What is the troposphere?
Layer of the Earth?s atmosphere, from sea level to about 10-15 km. altitude, containing most of the weather.
What is the winter solstice?
Extreme southern position of the Sun on the celestial sphere, south of the celestial equator (winter refers to the northern hemisphere).
What is the zenith?
Point on the sky directly overhead.
What is the zodiac?
Band on the sky, centered on the ecliptic, and about 18 degrees wide, through which the Sun, Moon and planets appear to move through the course of each year.
What are the Galilean satellites?
Four satellites of Jupiter discovered by Galileo who first named them Medicean satellites, after Cosimo de Medci, his patron.