Space - Science 9

What is a frame reference?

the perspective or pov from which you observe and measure things like position, speed, and motion

• stationary frame

• moving frame

What are celestial bodies?

the sun, moos, planets, and stars

What are celestial bodies measured in?

degrees

• altitude-azimuth coordinates

What is azimuth?

A measurement in degrees, clockwise from the north

• measured by compass

  • N: 0

  • E: 90

  • S: 180

  • W: 270

What is altitude?

A measurement in degrees from the horizon

• measured by astrolabe

  • horizon: 0

  • halfway: 45

  • zenith (directly above): 90

What is a geocentric model?

The model of the universe with earth at the centre and all the celestial bodies orbiting around it

What are epicycles?

A small circle that moves along a bigger circle

• old idea that attempted to explain how planets move in the sky

What is a heliocentric model?

The model of the universe with sun at the centre and earth as one of the planets orbiting around the sun

• used to be widely opposed and went against many religious beliefs

What is a telescope?

A device used to magnify objects at great distances

• ocular lens: lens we look through to see an object

• objective lens: large lens at the front of the telescope

  • invented in 1600’s

How did Galileo discover that the universe was heliocentric?

Other planets had moons

What is an ellipse?

a stretched out circle in which the planets orbit around the sun

• has 2 foci (focuses): one is the sun, one is empty space Y

What is universal gravitation?

all objects with mass attract all other objects with mass

What is resolving power?

How much detail that can be observed

• a telescope with a large diameter objective lens has more resolving power than one with a smaller lens

What are refracting telescopes?

Uses lenses to bend light to produce a magnified image

• used 2 lenses

What are reflecting telescopes?

Uses a curved mirror as the objective

• ocular is still a lens

What are catadioptric telescopes?

telescopes that have reflecting mirrors and refracting lenses to focus light and produce clear images

What is spectrum and its types?

white light spread into its colours or wavelengths

• continuous spectrum

• absorption spectrum

• emission spectrum

What is a spectroscope?

device that produces a focused spectrum of light

• light is passed through a thin slit before passing through a prism which gives a spectrum much finer detail

What are spectral lines?

dark or bright narrow lines in a spectrum caused by atoms absorbing or releasing/emitting light energy

• absorption dark lines (electrons jump up)

• emission bright lines (electrons drop down)

What is an emission spectrum?

light passing through gas at a low pressure

• bright spectral lines

• electrons drop down and release energy

What is a continuous spectrum?

When light is passed through high pressure gas or hot solid or liquid

• All colours produced

What is an absorption spectrum?

When light from a continuous spectrum is passed through a cooler gas

• dark spectral lines

• electrons jump up and absorb energy

What is spectroscopy?

The study of light and interactions with matter (elements giving off different colors of light when heated to incandescence)

What is magnification and its formula?

the process of making an image of an object appear larger than its actual size, by using a lens or mirror

• M = focal length of objective/focal length of eyepiece

What is diffraction?

the bending and spreading of waves (like light or sound)

• usually occurs when passed through an edge or narrow opening

What is spectra?

multiple spectrums

ex. scientists study the spectra of stars to see what they are made out of

What are diffraction gratings?

a device made of many closely spaced slits

What kind of spectrum does the sun have?

absorption spectrum

• the hot object is the sun, the cool gas is the sun’s atmosphere leaving us with dark lines on its spectrum

What is the doppler effect?

a change in the observed frequency and wavelength due to the motion of the source or the observer

• ambulance approaching:

  • moving towards: waves compress, higher pitch and shorter wavelength

  • passes/moving away: waves spread out, lower pitch longer nd wavelength

• red shift

• blue shift

What is redshift in the doppler effect?

moving away from us

• shift right

• when the lines in a spectrum shift towards the red end (longer wavelength)

What is blueshift in the doppler effect?

moving towards us

• shift left

• when the lines in a spectrum shift towards the blue end (shorter wavelength)

What is focal length, point, and plane ?

focal length

• the distance from a lens or mirror to where light focuses/focal point

focal point

• the exact spot where light rays meet after diffraction

focal plane

• the flat surface where a lens or mirror brings light from a distant object into focus to form an image

How do you get a clear image in a telescope?

the objective lens forms a real image at its focal plane, and the eyepiece is adjusted to focus on that image clearly

• If the eyepiece is too close or too far, the image will appear blurry, like a magnifying glass

What is spectral analysis?

The process of studying the frequencies or wavelengths in a signal or light to identify its components

Why do astronomers continue to build larger telescopes?

larger telescopes increase the surface area of the objective which means more light is collected to do a spectral analysis

What are adaptive optics?

a technology that adjust telescopes mirrors to remove the twinkling (distortion) of stars caused by our atmosphere

• computer softwares can also correct distorted images after collected by telescope

What is parallax?

The apparent shift in position of an object based on the position of the observer

• used to measure distances

What is triangulation?

an indirect method of measurement using triangles to calculate an unknown distance

• the further apart the observation points are, the more accurate the calculation will be

What are astronomical units (AU)?

the distance from the sun to earth

• around 150 000 000 km

What is a light year?

the distance light will travel in one year

• about 9.46×10^12 km

What is radio astronomy?

the study of stars using radio waves

What is the electromagnetic spectrum?

complete range of all types of electromagnetic radiation, includes all forms of light and energy that travel through space

shortest to longest:

• radio waves

• microwaves

• infrared

• visible light

• ultraviolet'

• x-rays

• gamma rays

What is electromagnetic radiation?

energy that travels through space in form of waves

• travels ae speed of light

What are radio objects?

objects in space that emit strong radio waves, which can be detected with radio telescopes

• the sun and jupiter are our brightest radio objects

• in radio telescopes, the louder the hiss, the larger amounts of radio waves given off

What is inferometry?

a method of combining signals from two or more radio telescopes to make a sharp image

• radio waves provide images with much less resolution than light waves

• Very long baseline inferometry: combine signals from telescopes around the world to produce 100x quality photos

Two types of telscopes?

radio and optical telescopes

What is a rocket?

a tube containing combustible material that exits the tube at high speed from one end when burned

• based on Newtons 3rd law; for every action there is an opposite and equal reaction

• to go forward gases must exit as a high velocity

What is a payload?

the object carried by the rocket

What is exhaust velocity?

the speed at which gas or fuel is pushed out of a rocket engine

What are liquid fueled rockets?

rockets with liquid fuel which has high exhaust velocity

• made by Robert Goddard

What are staged rockets?

when rockets have lower sections of the rocket drop off when their fuel is gone to allow the lighter upper section to fly higher and faster

• made by Robert Goddard

What are ballistic missiles?

a rocket carrying an explosive payload

• first ballistic missile was the German V2 Rocket

What are probes?

a spacecraft that travels through space to collect scientific information

What is gravitational assist?

a technique used by spacecrafts to gain speed and change direction by flying close to a planet or moon

What is a satellite?

an object which orbits another larger celestial body

• allows communication around the world

• natural satellites: naturally orbiting object such as the moon

• artificial satellites: human-made object placed into orbit

What is low earth orbit?

• 200-800 km high

• orbits in around 1.5 hours

• requires moving antennae to track

What is geosynchronous orbits?

• about 36 000 km high

• orbits once a day (syncs to earth’s rotation)

• tracked with stationary antennae

What is remote sensing?

taking measurements of earth from space

• ex. tracking weather, erosion, pollution

What is GPS?

Global Positioning System is a navigation system that provides location info

• developed by military

• requires at least 4 GPS satellites

What are CDD’s?

Charged Coupled Devices convert light signals into electric signals