Download Intro L4 IQ

IQ
• Most changes in the
appearance of the sky
are caused by the Earth’s
revolution.
• T
• F
IQ
•
•
False! “Revolution” refers to
the orbital motion of the Earth
about the Sun. These are
“annual” changes that happen
once per year. The seasonal
(annual) changing of
constellations depends upon
revolution.
Diurnal changes, for example,
the transit of stars during the
course of the night (or the sun
during the day) are caused by
the Earth’s rotation. Diurnal
changes are far more obvious
than annual changes
IQ
• Two theories that can explain
the apparent (observed)
motion of planets are the
“geocentric” (Earth-centered)
and “heliocentric” (Suncentered) models. The
accepted model today is:
A. Geocentric
B. Heliocentric
IQ
• B. “Heliocentric” is
the correct answer!
• Ancient astronomers
thought that the Earth was
the center of the universe.
Well, we’re not even the
center of the solar system!
The Sun is located at the
center of our solar system.
IQ
• Sir Isaac Newton
• When not inventing
the calculus or
defining gravitational
force, Isaac worked as
a stand-up comic
across Europe.
IQ – Schedule Information
• Our first test is scheduled for Monday, 14
February. We are on schedule to have the
test on this date. Plan on it!
• On Monday, 7 February we will have a
practice test to familiarize you with the type
of tests you’ll see the rest of the semester.
IQ
• A planet moving in a
circular orbit about a
star experiences:
• A. Good vibrations
• B. Uniform motion
• C. Accelerated motion
• D. The Taos Hum
IQ
• C. Accelerated motion is
correct.
• The planet is in a closed
orbit, therefore it is bound to
the star by the force of
gravity. Where there is a
force, there is an
acceleration.
• E.g. F=ma, where F is the
force on mass m resulting
from acceleration a.
IQ
• Parallax is a direct
technique to measure
the distances to nearby
stars by using:
• A. Cepheid variables
• B. The distance ladder
• C. One’s thumb
• D. Trigonometry
IQ
• The answer is D,
trigonometry.
• Parallax is the
measurement of the
apparent motion of nearby
star relative to much more
distant stars caused by the
revolution of the Earth
about the Sun.
IQ
• Light is one form of
electromagnetic radiation.
• T
• F
IQ
• True!
• Electromagnetic radiation
carries to us most of the
information we ever get
from the universe. It is
characterized by its
“wavelength.” Radio
waves are very long
wavelength and x-rays are
very short wavelength
electromagnetic radiation.
The wavelength of light is
in between.
BREAKING NEWS!
• These are the primordial thermal fluctuations present at the
creation of the universe 13.7 billion years ago!
• The amplitude (red to blue, or hot to cold) is approximately
1 x 10-5 Kelvins.