Exam 1 Review Astronomy

how much time would it take the light from a solar flare on the sun to reach earth?

• 10 hours

• 8 minutes

• 1 day

• 11 years

A light year is the measure of ____

• distance

• time

• speed

• mass

we only observe events that happened in the past because ____

• it takes time to analyze data

• the speed of light is finite

• the universe is very old

• our telescopes are not large enough yet

which of the following does not use light-year in the right way?

• it's about 4 light-years from here to Alpha Centauri

• it will take me light-years to complete this homework assignment

• A light-year is about 10 trillion kilometers

• the milky way galaxy is about 100,000 light-years in diameter

We can describe the position of an object in our local sky by stating its ________.

•  

  altitude and meridian

•  

  altitude and direction (azimuth)

•  

  latitude and direction (azimuth)

•  

  latitude and longitude

The angular sizes of the Sun and Moon are about the same because ________.

•  

  both objects have the same physical size

•  

  both objects are located the same distance away

•  

  the Sun is larger in size than the Moon by the same factor (about 400) that it is farther in distance

•  

  their angular sizes are an illusion created by their apparent locations on the celestial sphere

suppose we look at 2 galaxies: galaxy 1 is twice as far away as galaxy 2. in that case ___

• we are seeing galaxy 1 as it looked at an earlier time in the history of the universe than galaxy 2

• we can't say anything about these galaxies except for their distances

• they are both the same distance away from us

• we are seeing galaxy 1 as it looked later in time in the history of the universe than galaxy 2

shortly after the big bang, the chemical composition of the universe was ___

• about equal amounts of all the elements

• hydrogen only

• almost entirely helium and hydrogen

• about the same as it is today

If you locate the north celestial pole in your local sky and measure its altitude, then you will know ________.

•  

  your latitude and longitude

•  

  your latitude and the direction that is due north for you

•  

  your longitude and the direction that is due north for you

•  

  your latitude, longitude, and local time

on the scale of the cosmic calendar, in which the history of the universe is compressed to 1 year, when did the sun and earth form?

• january

• december

• february

• septemeber