Astronomy study guide for final

Which of the following types of stars will spend the shortest time (the least number of years) on the main sequence?

B

The Milky Way is thought to be which type of galaxy from the class notes/lecture?

Barred Spiral

Working with the 2.5-meter telescope _______, was able to resolve individual stars in several of the brighter spiral-shaped nebulae, including M31, the great spiral in Andromeda

Edwin Hubble

What does the Fermi Paradox say?

Given all the time since the Big Bang and all the stars, why has some form of intelligent life in the Galaxy not established a network throughout the Galaxy and visited us?

_______ developed a technique to use cepheid variables stars to estimate distances in the universe.

Henrietta Leavitt

Which of the following statements is true of Einstein's famous equation E = mc2?

It emphasized for the first time that matter can be converted into energy and vice versa.

The first search for radio messages from extra-terrestrial civilizations was called

Project Ozma

The astrophysicist who first calculated the highest mass that a dying star can have and still be a white dwarf was

S. Chandrasekhar

_______ is the variable on the horizontal axis (or x-axis) for the H-R Diagram and is listed from ___ to _____

Temperature, high, low

Which technique allows astronomers to detect exoplanets by the planet dimming the star's light as it passes in front of the star?

Transit method

The first astronomer to show that spiral nebulae (today called spiral galaxies) have large Doppler shifts was

Vesto Slipher

At first, right after the Big Bang, the universe was too hot for nuclei and electrons to combine into the kinds of neutral atoms that are familiar to us today. How soon after the beginning did it become cool enough for neutral atoms to form?

a few hundred thousand years

A star moving toward the Sun will show:

a shift in the spectral lines toward the blue end (as compared to the laboratory positions of these lines)

A star that is quite hot and has a very small radius compared to most stars is called

a white dwarf

One of your good friends who is on a diet asks you to point out the stars with the smallest mass on an H-R diagram that you are studying. Where are you sure to find the stars with the lowest mass on any H-R diagram?

among the stars at the bottom right of the main sequence

If an astronomer wants to find and identify as many stars as possible in a star cluster that has recently formed near the surface of a giant molecular cloud (such as the Trapezium cluster in the Orion Nebula), what instrument would be best for her to use?

an infra-red telescope (and camera)

Which color star is likely to be the hottest?

blue

At an astronomical conference, an astronomer gives a report on a star that interests astronomers because of hints that it may have a planet around it. In his report the astronomer gives the average speed with which this star is moving away from the Sun. How did the astronomer measure this speed?

by looking at the Doppler shift in the lines of the star's spectrum

If we cool down a balloon to 77 K with liquid nitrogen, the pressure inside the balloon will _____ and the volume of the balloon will _____

decrease, decreaseWhich color star is likely to be the hottest?Which color star is likely to be the hottest?

Currently the furthest observable galaxies are moving so fast away from us that the light from their stars has redshifted so much that they are more observable in the part of the electromagnetic spectrum.

infrared

Measurements show a certain star has a very high luminosity (100,000 x the Sun's) while its temperature is quite cool (3500 K). How can this be?

it must be quite large in size

On a H-R diagram, where would we find stars that are cool and dim?

lower right

When energy is first produced by fusion deep in the core of the star, that energy moves outward mostly by what process?

radiation

Which band of the electromagnetic spectrum do astronomers suggest is likely to be the best (cheap, little competition from nature, penetrates atmospheres) for communication between civilizations around different stars?

radio waves

Astronomer have concluded that pulsars are

rotating neutron stars

Which of the following stages will our own Sun go through in the future:

spending a long time on the main sequence expanding to become red giant giving off a planetary nebula eventually fusing helium into carbon ALl OF THE ABOVE

Elements heavier than iron can be created during:

supernova explosion

The reciprocal of the Hubble constant (1/H) is a rough measure of the:

the age of the universe

What incident in a massive star's life sets off (begins) the very quick chain of events that leads to a supernova explosion?

the fusion of iron

Astronomers identify the "birth" of a real star (as opposed to the activities of a protostar) with what activity in the star?

when nuclear fusion reactions begin inside its core