Chapter 1&2 Flashcards
What is the Universe?
The totality of everything in existence
What do scientists do to test the validity of a hypothesis?
Conduct experiments and observations
How is the number 500,000 written in scientific notation?
5x10 to the 5th
What is a nanometer?
One billionth of a meter
Or
10 to the -9
How many arc seconds are there in an angle of one degree?
3600
1* = 60’ (arc minutes)
1’ = 60” (arc seconds)
Which represents the biggest distance:
1 pc, 1 AU, or 1 ly?
1 pc= 3.262 ly
1 ly = 6x10 to the 12th miles
1AU= 93x10 to the 6th miles
Today, what is a pattern of bright stars called?
Asterism
Why do we have seasonal stars?
Because of the Earths orbit around the Sun
What causes the seasons we experience on the Earth?
The 23.5* tilt of the Earth’s rotation axis
What type of day is the true rotation period of the Earth?
Sidereal Day
If a star rises tonight at 11:00 pm, when will it rise tomorrow night?
10:56pm
Stars rise about 4 minutes earlier each night
Where must you be on the Earth to have the north celestial pole at your zenith?
On the North Pole
What is the ecliptic?
Earths orbital plain and the apparent path of the Sun
What two celestial coordinates are used to specify the positions of objects in the sky
Declination and Right Ascension
Why is Polaris not always the North Star for the Earth
The Earth’s rotation axis precesses
What is retrograde motion for the planets
Motion backwards from normal motion
As far as we know, who first accurately measured the size of the Earth
Eratosthenes
What type of model was the one promoted by Copernicus
Heliocentric
What was Tycho’s major contribution to astronomy
Accurate planetary positional data
According to Kepler’s laws, where is the Sun located in a planet’s orbit
At one focus of the ellipse
What is meant by inertia
Tendency for constant velocity motion
What did Galileo prove by observing Venus and Jupiter through his telescope
The Earth is not the center of all motion (the geocentric model is wrong)
What is Newton’s second law of motion
Force equals mass times acceleration, F=ma
Why do objects weigh more on Earth than they do on the Moon
The Earth is much more massive than the moon
What is Earth doing at this very moment
Freefalling into the Sun
According to Newton, light behaves as if it is made of what
Particles (colored)
According to Young, light seems to act like what
A wave (of some unknown type)
Did Maxwell confirm Young’s result? If so, according to Maxwell what is light
Yes- light is an electromagnetic wave
According to Einstein, energy within light comes in the form of what (and its name)
Particles (photons)
Today, what do physicists state about the nature of light
Light has a “wave-particle duality” of nature (it shows both aspects)
Which has a longer wavelength: violet light or red light? Which has more energy
Red light has a longer wavelength (and less energy) than violet light
Which differs greatly from others: x-rays, radio waves, sound waves, visible light
Sound waves (all of the others are light)
You want to observe the x-rays that an object emits. Where is your telescope located
In space (above the Earth’s atmosphere)
Sirius is white, Betelgeuse is red, and Spica is blue. List these stars from hottest to coolest
Spica (blue) is the hottest, then Sirius, and the Betelgeuse (red) is the coolest
What do astronomers use to determine the chemical composition of the stars
Spectroscopy (spectral analysis)
A very hot, dense, glowing object produces what type of spectrum
Continuous
A warm glowing cloud produces what type of spectrum
Emission
The Sun (and other stars) produces which type of spectrum
Absorption
Are normal atoms overall positively, negatively, or neutrally charged
Normal atoms are always neutrally charged
According to Rutherford’s results, the nucleus of the atom is what (three answers)
Small, massive and positively charged
Within the atom, where are neutrons and protons located
The nucleus (center)
When atoms absorb photons, the electrons can move to (——-) orbits
Higher
When electrons move to (—–) orbits, atoms emit photons
Lower
What transitions of the electron within the hydrogen atom result in the Balmer series
The second and all the higher orbits
The spectrum of the light from a star exhibits a blue shift. What does this mean
It’s moving towards us
The wavelength of the hydrogen alpha line is 656.28 nm. In a stars spectrum, this line is observed at a wavelength of 657.28.
Is the star moving towards or away from us?
How do u immediately know?
It is moving away from us, its wavelength is now longer, or a red shift
