Foundational astronomy vocabulary including orbits, parallax, redshift, and light-years.
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- What is a light-year?
- A unit of distance equal to how far light travels in one year in vacuum
- Define parallax
- The apparent shift in position of a nearby object against distant background when viewed from two different locations
- What is redshift?
- A shift in light from an object toward longer wavelengths, usually indicating the object is moving away
- What is blueshift?
- A shift in light from an object toward shorter wavelengths, usually indicating the object is moving toward us
- Define orbit
- The curved path followed by an object around another object under the influence of gravity
- What is eccentricity?
- A measure of how elliptical an orbit is, ranging from 0 (circular) to 1 (parabolic)
- Define escape velocity
- The minimum speed an object must reach to break free from gravitational attraction without further propulsion
- What is luminosity?
- The total amount of energy radiated by a star per unit time in all directions
- What is apparent magnitude?
- The brightness of a star as observed from Earth
- What is absolute magnitude?
- The intrinsic brightness a star would have if placed at a standard distance of 10 parsecs
- Explain parallax angle
- The angle at which a nearby star appears to shift against the background of distant stars as Earth orbits the Sun
- What is an AU?
- Astronomical Unit, the average distance from Earth to the Sun, approximately 150 million kilometers
- What is a solar mass?
- The mass of the Sun, used as a standard unit to express the mass of other stars
- Define photosphere
- The visible surface layer of the Sun from which light is emitted
- What is the chromosphere?
- A thin layer of the Sun's atmosphere above the photosphere, visible during a total solar eclipse