Unit 4 - Flashcards

Front 1

Frame of Reference

Back 1

set of axes that is used to describe the position or motion of things

Front 2

Celestial Bodies

Back 2

natural objects visual in the sky

Front 3

Constellations

Back 3

groupings of stars that form patterns in the night sky (eg. Ursa Major) - officialy there are 88 constellations

Front 4

Planets

Back 4

A celestial body moving in an elliptical orbit around a star

Front 5

Ancient Myths

Back 5

myths, folklore and legends wre used to explain what ancient people observed in the night sky

Front 6

Azimuth

Back 6

the angle between the most northerly point of the horizon and the point directly below a celestial body; also the horizontal angle or direction of a compass bearing

Front 7

Altitude-Azimuth Coordinates

Back 7

altitude tells you how far above the horizon the object is - a point overhead has an altitude of +90 degrees and a point straight underneath has an altitude of -90 degrees - points on the horizon have 0 degree altitudes.

azimuth determines which compass direction it can be found in the sky - an azimuth of 0 degrees puts the object in the East and an azimuth of 180 degrees puts the object in the South.

Front 8

Astrolabe

Back 8

1.An instrument formerly used to make astronomical measurements, typically of the altitudes of celestial bodies, and in navigation for calculating latitude, before the development of the sextant.

Front 9

Compass

Back 9

1.An instrument containing a magnetized pointer that shows the direction of magnetic north and bearings from it.

Front 10

Earth Centered/Geocentric Model

Back 10

The Earth was fixed and the center of the solar system with all celestial bodies in space rotating around it. Geocentric model was created by Arisotle's model

Front 11

Sun Centered/Heliocentric Model

Back 11

Nicholas Copernicus developed this model, in which the Sun was fixed and a rotating Earth revolved around it

Front 12

Telescope

Back 12

they allow us to see objects which are very distant in space. Hans Lippershey made one of the first telescopes - but Galileo was the one who made pratical use of it. Optical telescopes are 'light collectors' - they collect and focus the light from the stars. There are two types of optical telescopes - refracting which uses a lens and reflecting which uses a mirror

Front 13

Ocular Lens

Back 13

the eyepiece

Front 14

Objective lens

Back 14

the larger lens at the front of the telescope

Front 15

Eyepiece

Back 15

The lens or group of lenses that is closest to the eye in a microscope, telescope, or other optical instrument.

Front 16

Galileo

Back 16

he was the first to make pratical use of a telescope. He made several observations including:
- The moon had blemishes (mountains and craters like the Earth).
- Sun spots indicated that it rotates on its axis.
- Jupiter’s moons orbit the planet.
- Planets were disk-shaped, but because the stars were still pinpoints, they were further away.
his observations supported the sun-centered model because the moons he observed orbiting jupiter indicated that the earth was not the centre of the universe

Front 17

Hans Lippershey

Back 17

in 1608, Hans Lippershey made one of the first telescopes

Front 18

Resolving Power

Back 18

produces finer detail of the object being viewed due to the diameter of the objective lens

Front 19

Refracting telescope

Back 19

It uses two lenses to gather and focus starlight - Galileo used a refracting telescope

Front 20

Reflecting telescope

Back 20

Designed by Isaac Newton in order to focus colors at the same point - they use mirrors as the optics to focus and bounce light

Front 21

Ellipse

Back 21

an oval formed around two foci (a circle is formed around one focus); the orbital paths of planets travelling around the sun are ellipses

Front 22

Universal Gravitation

Back 22

Every point mass attracts every single other point mass by a force pointing along the line intersecting both points

Front 23

Spectrum

Back 23

Isaac Newton passed a beam of light through a prism to produce a spectrum of color.
passing light through a narrow slit before sending it through a prism (a spectroscope is a the device that does this) the spectrum will be in more detail

Front 24

Spectroscope

Back 24

an instrument used by astronomers to observe and measure the spectrum of a star

Front 25

Spectral lines

Back 25

Joseph von Fraunhofer used a spectroscope to observe the spectrum produced by the Sun. He noticed dark lines, called spectral lines, but didn’t know what they meant. He found these spectral lines throughout the solar system.

Front 26

Spectroscopy

Back 26

the significance of spectral lines was then discovered about 50 years later - when two chemists (Bunsen and Kirschoff) used a spectroscope to observe various chemicals when they were heated - they found some lines missing in some of the chemicals and each particular element had its own unique spectral lines. which led to the science of spectroscopy - the study of spectra - they found 3 types of spectra

Front 27

Continuous Spectrum

Back 27

a

Front 28

Emission/bright line spectrum

Back 28

a

Front 29

Absorption/dark line spectrum

Back 29

a

Front 30

Diffraction grating

Back 30

Besides splitting light using spectroscopes or prisms, a diffraction grating can, by using thousands of closely spaces slits produce much better detail in the spectrum it produces.

Front 31

Spectral Anaylsis

Back 31

To determine a star’s composition, the spectra of a star are compared to known spectra of elements.
Spectrometer is used to do this

Front 32

Doppler effect

Back 32

the apparent change in frequency of sound, light, and other waves as the observer and
the wave source move towards or away from each other; also referred to as “Doppler shift”

Front 33

Red shift

Back 33

Object is moving away

Front 34

Blue shift

Back 34

object is moving away