Transcript Celestial Tools and Measurements

Celestial Tools and Measurements
Coordinate Systems
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Celestial Sphere
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Imagine a sphere that surrounds our planet in
which all the stars are attached. This sphere is
allowed to rotate freely around the planet.
Celestial Equator
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Located above the Earth’s
Equator
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Right Ascension
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East-West Measurement similar to longitude
Declination
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North-South Measurement similar to latitude
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Ecliptic
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Sun’s path relative to the Stars
Parallax
The angle across the sky a star seems to move
in reference to the background of stars
between two observations that are 6 months
apart.
 The measurements are taken when the planet
is on opposite sides of the Sun.
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Parallax
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The farther the
star, the harder it is
to measure because
it doesn’t move
very much.
Types of Telescopes
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Refracting Telescope
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Uses a combination of lenses to created a larger
image.
Types of Telescopes
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Reflecting Telescope
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Uses mirrors or other types of reflective surfaces
to focus the signals onto a receiver.
Electromagnetic Radiation
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Electromagnetic radiation can be described in terms of
a stream of photons. These are massless particles each
travelling in a wave-like pattern and moving at the
speed of light.
Each photon contains a certain amount (or bundle) of
energy. The only difference between the various types
of electromagnetic radiation is the amount of energy
found in the photons.
Radio waves have photons with low energies,
microwaves have a little more energy than radio waves,
infrared has still more, then visible, ultraviolet, X-rays,
and ... the most energetic of all ... gamma-rays.
Electromagnetic Radiation
EM radiation from space is unable to reach
the surface of the Earth except visible light,
radio wave, and UV light
 Astronomers can get above enough of the
Earth's atmosphere to “see” the rest of the
spectrum.
 This is done by building telescopes on
mountains, in airplanes, or in satellites.
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Electromagnetic Radiation
Gamma Rays
Radiated by Objects at this temperature:
 More than 100 000 000
Pulsar
Gamma Rays
Typical Sources
 Accretion Disks around Black Holes
Gamma Rays
Technology
Fermi Gamma Ray Space
Telescope
X-Rays
Radiated by Objects at this temperature:
 1 000 000 – 100 000 000 k
X-Rays
Typical Sources
 Gas in Clusters of galaxies; supernova remnants;
stellar corona
Our Sun
Stephan’s Quintet
X-Rays
Technology
ROSAT
Chandra X-Ray
Observatory
Ultraviolet Rays
Radiated by Objects at this temperature:
 10 000 – 1 000 000 K
New Star Formations
Ultraviolet Rays
Typical Sources
 Supernova remnants; very hot stars
Andromeda
M81
Ultraviolet Rays
Technology
Hubble Telescope
Visible Light
Radiated by Objects at this temperature:
 1000 – 10 000 K
Visible Light
Typical Sources
 Planets; stars; some satellites
Visible Light
Technology
 Hubble Telescope
Infrared
Radiated by Objects at this temperature:
 10 – 1000 K
Infrared
Typical Sources
 Cool clouds of dust and gas; planets
Helix Galaxy
Sombrero Galaxy
Infrared
Technology
Space Infrared
Telescope Facility
SOFIA
Microwaves
Radiated by Objects at this temperature:
 1 – 10 K
Microwaves
Typical Sources
 Cool clouds of gas; including those round newly
formed stars; the cosmic microwave background.
Microwaves
Technology
 What are the values
of the Big Bang
Theory?
 How did structures of
galaxies form in the
Universe?
 When did the first
structure of galaxies
form?
Wilkinson Microwave
Anisotropy Probe
(WMAP),
Radio Waves
Radiated by Objects at this temperature:
 Less than 1 K
Radio Waves
Typical Sources
 Radio emissions produced by moving electrons in
a magnetic field.
Radio Waves
Technology
Arecibo radio
observatory
Quiz
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What is the Doppler Effect and how does it relate to stars?)
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Why do some stars explode as supernova? What determines its type of
Supernova?
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Explain the relationship between the type of death of a star and the star’s
initial mass and size.
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Astronomers can learn many things about a star from its spectral lines?
Name three things they can determine from the spectral lines.
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How would an increase in mass affect the basic properties of a star?
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What is the purpose of the Main Sequence? (3 marks)