unit 5 space exploration · telescopes a telescope is a device that magnifies objects at great...

UNIT E

Space ExplorationPart 2

- SCIENCE 9 -

How do we know so much about what we cannot actually see or measure???

Measuring Distance in Space● Proxima Centauri, the next

closest star to us, is 4.28 light

years away.

● How do we know this if there’s no

ruler that long?!?!

parallax & triangulation

Measuring Distance in Space• Parallax is the apparent shift in an object’s position when viewed from different

angles.

• We can use parallax to measure the distance to a celestial object using triangulation

Triangulation● Triangulation is the process of determining

the distance to an object using either scale

factor or trigonometry (triangle math)

● To use the triangulation method, you need to

know the length of one side of the triangle (the

baseline) and the measure of the angles

created when imaginary lines are drawn from

either end of the baseline to the same point on

the distant object.

Triangulation• To create your scale diagram, start by choosing an

appropriate scale (i.e. 20 m irl = 1 cm in drawing)

• Use this scale to measure & draw the baseline on

your diagram (i.e. 120 m = 6.0 cm)

• Use a protractor & a ruler to draw a line from each

end of the baseline at the angles you recorded. Stop

when the lines intersect.

• Use a ruler to measure the shortest distance from

the baseline to where your two lines intersect

• Use the scale factor of your drawing to determine

the actual distance to the object.

Triangulation PracticeHow far away is this star from the back of the class?

1) Set up a baseline parallel to the star

2) Measure angles created from the ends of the baseline to the star

3) Create a scale diagram of the situation

4) Determine the scale diagram distance to the star and translate to the actual

distance to the star

How Do Astronomers Use Triangulation to Measure the Distance to Stars?

Astronomers determine the

distance to the star by

viewing it from two angles:

Earth’s summer position

and Earth’s winter position

Telescopes• The invention of the telescope in

1608 led to a wave of new

discoveries, changing the way

we saw our universe and

ourselves

• The first person to use a

telescope to make major

discoveries was Galileo Galilei

Galileo Vs. The Church• The telescope allowed astronomers to make new

observations about the heavens; many of these

observations led to conclusions about our universe that

contradicted what the church was advocating at the

time.

• Galileo was one of the first to reveal these new details

of celestial bodies, suggesting that the sun, moon, stars

and even our planet are not “perfect” as previously

believed.

• He also observed the rotation of four small moons

around Jupiter; this finding got him in a lot of trouble

with the church. Why do you think they would care?

Sun-spots and craters on the

moon, as observed by Galileo

Inquiry-Based Science• Galileo is considered by many to be the

first true scientist. Before him, many did

not actually test their theories and models

by methods of observation.

• Galileo’s findings supported Copernicus’s

heliocentric model of the solar system,

which we now know to be true.

• Galileo paved the way for future scientists,

insisting that the scientific process must

involve the development of testable

theories based on a set of replicable

observations.

Telescopes A telescope is a device that magnifies

objects at great distances

A simple telescope has 3 parts

1) Objective Lens: Where light enters

the telescope

2) Focal Length: Distance from the lens

to the place where the light beams

converge (focus).

3) Ocular Lens or Eyepiece: Where

light leaves the telescope to enter the

eye.

Telescopes• Telescopes are only as good

as their resolving power

• Resolving power refers to the

clarity of a magnified image

• Telescopes with a higher

resolving power are able to

see finer details in objects that

are far away

Types of Telescopes1. REFRACTING TELESCOPE

● First kind of telescope invented (would have been used by Galileo)

● Refracting telescopes use lenses to magnify objects in view

Galileo, early 1600s

Types of Telescopes2. REFLECTING TELESCOPE

● Uses mirrors to magnify objects in view

● Better resolution than refracting telescopes

Modern Day Telescopes• Most astronomers today use spectroscopy to

examine stars and determine their composition

• This method requires bigger, better telescopes

which collect significantly more light

compared to telescopes used in the past

• Newer telescopes use powerful computers

which take images from two or more telescopes

and combine them – this process is called

INTERFEROMETRY.

Hubble Space Telescope Reflecting telescope

orbits Earth once every 90 minutes

Advantages over land-based optical

telescopes: images are not distorted by

night, clouds, or air pollution

The Extraordinary Hubble Space

Telescope (18 min)

https://youtu.be/-nNiULl5_2k

Hubble Space TelescopeWhere can I see pictures taken by the

Hubble?

http://hubblesite.org/

http://hubblesite.org/

Types of Telescopes3. RADIO TELESCOPES

● Collect RADIO waves instead of light waves

● Use computers to generate images from the radio

waves

● Information collected from radio telescopes

provided evidence that our galaxy is spiral shaped

● Two or more small radio telescopes can be

combined in an array to simulate the resolving

power of one large radio telescope. This is called

INTERFEROMETRY.

SATELLITES• A satellite is a smaller body that

orbits a larger one

• Can be natural (example: the moon)

or artificial (weather satellites, GPS)

ARTIFICIAL SATELLITESArtificial satellites have a variety of purposes including

1) Weather monitoring

2) Communication: radio, TV, GPS

3) Space Exploration: International Space Station (ISS), Hubble Space Telescope

Satellite OrbitsSome communication satellites are placed in a low earth orbit, while

others are placed in a geosynchronous orbit

• Objects in geostationary orbits appear

stationary to those on the earth’s

surface. Examples: weather, radio, and

tv satellites

• Objects in low earth orbits appear to

move across the sky. Examples:

Satellite phones and other

communication systems

International Space StationThe International Space Station (ISS) houses astronauts who collect

and monitor data from other satellites around the globe. These provide

us with information about weather systems and trends, carbon levels,

etc. on Earth

• The ISS orbits Earth once every 90 minutes – GEO or LEO?

ARTIFICIAL SATELLITESQ: Which satellites

can transmit signals

to a greater area of

Earth?

A: Geosynchronous

– the higher the

satellite, the greater

its area of coverage.

Global Positioning System (GPS)• GPS uses satellites to

determine the position of

objects on Earth

• There are 24 total GPS

satellites orbiting Earth.

• At any given time, there are

3 GPS satellites in range of

any given location on Earth.

Check Your Understanding


Hint: use the

process of

elimination to

determine the

aperture


The Hubble Space Telescope uses _i_ to _ii_ the

light into the focal point

What are stars

made of??

How do we know?

What are Stars Made of?• Isaac Newton discovered that when

a beam of light was passed through

a prism, it produced a rainbow

spectrum of colour.

• From this observation, he concluded

that white light is made up of all

wavelengths of colours.

• White light is the type of light

produced by our sun. Do all stars

produce the same type of light?

The Spectroscope● A spectroscope is a device that creates

a more focused, detailed spectrum of light

● When we look at the sun’s light through a

spectroscope, we actually see that there

are many small lines of missing light

● These lines are called spectral lines.

● What does this tell us about the light from

the sun?

The Spectroscope• When different elements are heated,

they begin to glow.

• If we observe these elements with a

spectroscope, we notice that each

element produces a unique of spectral

lines

• So, by comparing the spectral lines

produced by a star, we can determine

which elements is it composed of

HYDROGEN

HELIUM

NEON

SODIUM

MERCURY

Spectral Analysis• Which elements are present in

Mystery Star 1?

• Which elements are present in

Mystery Star 2?

HYDROGEN

MERCURY

CALCIUM

SODIUM

HELIUM

Mystery Star 1

Mystery Star 2

TRUE or FALSE?

The universe is

expanding

How do we know?

What happens to the spectral line pattern if the object is moving?

Object is

moving

towards us

Object is

moving away

from us

Wavelengths & the Doppler Effect● Spectroscopes not only tell us what a star is made

of, but also tell us how fast a star is moving towards

or away from us

● Red wavelengths indicate moving away; blue

wavelengths indicate moving towards

● This is comparable to the Doppler Effect; when an

object is moving away from us, its sound waves are

getting longer (like red wavelengths). When an

object is getting closer, its sound waves are getting

smaller (like blue wavelengths)

● Sheldon is the Doppler Effect for Halloween

https://youtu.be/Tn35SB1_NYI

https://youtu.be/Tn35SB1_NYI

http://youtube.com/v/FhfnqboacV0

http://youtube.com/v/FhfnqboacV0


Researchers study the spectrum of a star to determine the

star’s

A. total mass

B. temperature

C. composition

D. gravitational force


Given the spectra of the four gases,

what are two of the gases that are

present in the mystery star?

A. hydrogen and helium

B. hydrogen and calcium

C. helium and sodium

D. sodium and calcium

GEOCENTRIC MODEL

HELIOCENTRIC MODEL

ELLIPSES

TERRESTRIAL PLANETS

GASEOUS PLANETS

STAR

NEBULA

GALAXY

CONSTELLATION

TELESCOPE

REFRACTING TELESCOPE

REFLECTING TELESCOPE

HUBBLE TELESCOPE

ALTITUDE

ASTROLABE

AZIMUTH

ZENITH

SPECTROSCOPE

SPECTRAL ANALYSIS

RED SHIFT

BLUE SHIFT

LIGHT YEAR

PARALLAX

TRIANGULATION


Sometimes

the PAT is

about

“process of

elimination”!

unit 5 space exploration · telescopes a telescope is a device that magnifies objects at great...

Documents