Science 9: Space Exploration SE1 Vocabulary

SE1.1 - What do we understand about celestial bodies? SE1.2 - How have our views of the solar system changed? SE1.3 - How have telescopes been used to increase our understanding of space? SE1.4 - How can the composition of a star be determined using spectroscopy?

Celestial Bodies

All objects seen in the sky (the Sun, Moon, stars, and planets)

Constellations

Groupings of stars that form patterns, which appear like objects, and are given names (such as Orion, the Hunter)

Sky Coordinates

Locate a celestial body relative to a fixed Earth (as though the celestial bodies are circling Earth)

Azimuth

The angle measured clockwise from North when measuring altitude-azimuth coordinates

Altitude

The angle measured above the horizon in degrees when meausring altitude-azimute coordinates

Astrolabe

A device used to measure the altitude of an object

Compass

A device used to measure an object’s azimuth

Solstice

Either of the two times during the year when the sun is most northerly or southerly from the equator (shortest and longest day of the year)

Equinox

The days where days and nights are of equal length

Zenith

The point in the sky directly above an observer (90 degree altitude)

Geocentric Model

Earth centered Universe model, proposed by Aristotle

Heliocentric Model (Sun-centred)

A model of the universe that places the Sun at the centre with Earth, the planets, and Moons revolving around it

Universal Gravitaton

Newton’s law states that all objects attract all other objects, and provides an explanation for the planets’ elliptical orbits

Elliptical Orbit

An oval-shaped path due to gravitational interactions among celestial bodies

Aristotle

Greek philosopher that proposed Earth centered model (384-322 BC)

Ptolem

Greek philosopher attempted to explain retrograde motion by including small epicycles (AD 90-168)

Copernicus

Astronomer that proposed heliocentric system (orbiting sun)

Galileo

Improved the telescope in 1600s

Kepler

Predicted that the planets moved in elliptical orbits rather than circular orbits, explained retrograde motion (1571-1630)

Refracting Telescope

Invented by Lippershey/Galileo, uses lenses to gather more light than the human eye could collect on its own and focuses it. Used for planetary viewing.

Reflecting Telescope

Invented by Newton, uses a single or a combination of curved mirrors that reflect light and form an image. Used for deep sky viewing.

Radio Telescope

Invented by Jansky/Reber in the 1930s, detect radio waves from astronomical radio sources in the sky. Can penetrate dust clouds and access areas unavailable to optical telescopes, can be used day and night.

Resolving Power

Magnification

Focal Length of Objective Lens/Focal Length of the Eyepiece Lens

Interferometry

A technology that connects 2 or more telescopes to combine their images

Adaptive Optics

A technology for ground based telescopes that adjusts the mirrors of a telescope or the image they product to cancel the effects of atmospheric distortion

Electromagnetic Spectrum

The full range of electromagnetic radiation, organized by frequency or wavelength

Spectroscope

A scientific instrument that splits light into its different wavelengths, which humans see as different colours

Spectral lines

Dark or bright line in an otherwise uniform and continuous spectrum used to identify elements

Spectroscopy

Spectral analysis can be used to identify the chemical composition of distant stars. By comparing the black lines to the unique spectrum of each element, we can determine the composition of stars

Diffraction grating

A series of closely spaced slits

Spectral analysis

Spectral analysis can be used to identify the chemical composition of distant stars. By comparing the black lines to the unique spectrum of each element, we can determine the composition of stars