UNIT 5 Space Exploration · Telescopes A telescope is a device that magnifies objects at great...
Transcript of 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)
Hubble Space TelescopeWhere can I see pictures taken by the
Hubble?
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
Check Your Understanding
Check Your Understanding
Hint: use the
process of
elimination to
determine the
aperture
Check Your Understanding
Check Your Understanding
Check Your Understanding
The Hubble Space Telescope uses _i_ to _ii_ the
light into the focal point
BREAK
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
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
Check Your Understanding
Check Your Understanding
Researchers study the spectrum of a star to determine the
star’s
A. total mass
B. temperature
C. composition
D. gravitational force
Check Your Understanding
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
Check Your Understanding
Check Your Understanding
Check Your Understanding
Check Your Understanding
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
Check Your Understanding
Check Your Understanding
Check Your Understanding
Sometimes
the PAT is
about
“process of
elimination”!
Check Your Understanding