Astronomy Exam 2 Study Set

Water freezes at ________ degrees Kelvin.

+273

The orbits of the 8 planets in our solar system ______________.

lie in nearly the same plane

Put the following EM waves in order from longest wavelength to shortest wavelength.

microwave<optical<UV

Comets are ______________.

mostly rock/ice

You are standing on Earth's equator at noontime. the sun is at zenith (ie., altitude = 90 deg.). The date is

sept 21

The amount of time for a planet to spin 360 deg is its _________________.

sidereal day

Asteroids and comets are

leftover material from the formation of the SS

A 'spectrometer' takes a sound or light signal and

separates it into its constituent wavelengths

An acoustic wave in air has a speed of about 300 m/sec. A light wave (in empty space) has a speed about _____________ than acoustic waves.

1 million times faster

Stars A and B both emit blackbody spectra (this is true of 90% of all stars). The max (or peak) amplitude from star A is at frequency 5x10^14 cps. Star B has twice the temperature of star A. Then star B has max (or peak) amplitude at frequency = __________ cps (cycles per second).

1x10^15

How many major categories of planets do we have?

2

If you cut the wavelength of an EM wave to 1/3 its original value, then the new frequency will be __________ its original value.

3 times

For Earth, the difference between our solar and sidereal day is ________________.

4 min

Pretend a certain wave has a speed of 100 m/sec and a frequency of 20 cycles per sec (cps, or Hz). What is its wavelength?

5 m

Which of the following wavelengths is in the optical range of the EM spectrum (see Freedman book, pg 110). (nm stands for nanometer= 10^-9 meter)

500 nm

For a planet that has a 90 deg tilt (ie., tilted all the way over), put yourself on its north pole. What will be the altitude of the Sun at noon on its summer solstice?

90 deg

You discover 3 planets in our SS in circular orbits. They are all at 1 AU from Sun. The 3 differ only in the amount of tilt of their spin axis; A has 63 deg, B has 26 deg, C has 45 deg. Rank them in order of seasonal weather variations, from weakest to most extreme.

B<C<A

Why are our sidereal and solar days not identical?

E is traveling around the Sun

Which of the following refers to the process of "accretion"?

It is the growth of an object by accumulation of material sticking to it

You are in New York City. On _________ you will have more minutes of daylight than on any other day of the year.

June 21

Rank the following in order from smallest diameter to largest.

Mercury<Mars<Earth

Rank the following in order of mass, from lowest to highest.

Mercury<Mars<Uranus

If you had an imaginary bathtub huge enough, and put all of the 8 planets into it, which one would float? (Hint, look at the density in the table )

Saturn

Which of the following is a correct statement about the Celsius and Kelvin temperature scales?

Water freezes at 273 K

Newton used a glass prism, but today's spectrometers usually use _____________.

a diffraction grating

Just as there exist ___________ waves outside the human sensitivity of hearing, there exist ____________ waves outside the human sensitivity of eyesight.

acoustic, electromagnetic

A spectrum is a plot of what wave properties?

amplitude and frequency

Prior to 4 1/2 billion years ago,

an interstellar cloud started undergoing gravitational collapse

Atoms ______________________.

are mostly empty space

The electromagnetic waves reaching Earth from the Sun ___________________.

are necessary for life on Earth

The spectral lines from an atom are sometimes referred to as its 'spectral fingerprint ' or supermarket bar code, because ______________. You Answered

both fingerprints and spectral lines consist of individual lines that make a pattern that identifies the source

An atom contains 7 neutrons, 8 electrons, and 6 protons. It is _________. (hint, see Periodic Table of elements)

carbon (C)

Pretend you discover a new planet in our SS. It is at a distance of 4.8 AU from Sun and has 39 moons. It most likely is a ____________.

gas giant type planet

In the 1800s , astronomers discovered a new element in the Universe, called ____________.

helium

The continuous spectrum from the Sun

is approximately a blackbody spectrum

That the original 5 wanderers orbit in the counter-clockwise direction _____________.

is not required by Newton's laws

Pretend you discover a new planet in our SS and it has a diameter equal to 0.9 Earth masses. Which of the following is most likely true of your new planet?

it has a solid surface

Pretend you have discovered a new planet in our solar system. It is 25 Earth masses. Which of the following is most likely true of your new planet?

it is mostly gas and liquid

Put the following three colors in order from lowest frequency to highest frequency.

orange<yellow<green

What is emitted from an atom when an electron makes a transition from a high energy orbit to a lower energy orbit?

photon

When you change the wavelength of an acoustic wave, you change its _______________, and when you change the frequency of an EM wave, you change its _____________.

pitch, color

Which of the following EM wave is better able to reach ground level?

radio

A continuous blackbody spectrum is the shape of the spectrum that you often get from

solids and liquids

You have two spheres of the same diameter, labeled A and B. Sphere A contains 50 kg of gold; sphere B contains 45 kg of air and 7 kg of water. Which of the following is most likely correct?

sphere B has higher average density than A

The Hubble Space Telescope discovered _____________ in the Orion Nebula.

spinning pancake disks of gas/dust around young stars

Pretend you discover a new planet in our SS. It has an average density of 5 times the density of water. It most likely is a ____________.

terrestrial type planet

In the formation of our SS, there is a certain radius from the center of the disk, inside of which one expects to get _________ type planets and outside of which one gets __________ type planets.

terrestrial, gas giant

A nice feature of the "Solar Nebula Model of the Formation of our Solar System" is that it naturally accounts for this property of our SS.

that the orbits of most of the planets are approximately circular, that the asteroids are mostly R/M and the comets contain alot of ices, that all 8 planets lie in nearly the same plane, than most of the moons and planets orbit in the same direction

What is the main cause of Earth's seasonal weather variations?

the changes in the distribution of the sunlight on E's surface

The summer solstice refers to the moment when a planet is at the location on its orbit around the sun such that

the northern hemisphere recieves more sunlight than on any other day of orbit

Which of the following factors is the main reason why the inner 4 planets have a different chemical composition than the outer 4 planets.

the variation of temperature with distance from the center of the disk

Which of the following is a defining characteristic of the 'planetesimal' stage of planetary formation?

they are large enough so that their own gravity attracts more matter and they grow larger faster.

Astronomers want to do X ray astronomy in addition to optical astronomy because

you gain more info than if you restrict yourself to optical

Hydrogen atoms have an emission line at f = 4.57x10^14 cps. A cloud of glowing hydrogen atoms is moving fast towards you on Earth. Which is most likely correct?

you measure its frequency to be higher than 4.57x10^14 cps