Galaxies
How would you describe the shape of the Large Magellanic Cloud?
Irregular
Which statement best describes the Hubble ultra deep field image?
It shows very young galaxies in the early universe. Most of the galaxies in this field are too faint to be seen from ground-based telescopes. This image shows some of the most distant objects detectable in visible light. All of the above.
Which type of galaxy is very difficult to see, but (astronomers recently realized) may be very common?
dwarf elliptical
The galactic plane is obscured when observations are made using visible light. What do observations in other wavelengths reveal about this part of the galaxy?
The whole of the galactic plane is an active region in the Milky Way
The central plane of the galaxy is characterized in visible light by:
Obscuring clouds of dark gas and dust
The type of galaxy that consists almost entirely of old stars and is thus less blue (more yellow and reddish) than the other types is:
elliptical
Which type of galaxy is observed to contain mostly older stars?
elliptical
Our Milky Way Galaxy is what type of galaxy?
spiral
The type of galaxy that sometimes has a distinct bar of stars running across the central region is
spiral
Edwin Hubble developed a classification scheme for galaxies. By what characteristic did he classify galaxies?
their shape
Among irregular galaxies, what makes the Large and Small Magellanic Cloud especially useful for astronomers?
they are (for galaxies) very close to us, so they are easy to study
Which particular feature of a spiral galaxy is evident, even from this interior view of the Milky Way?
A central bulge and dust lanes.
Which of the following is NOT a characteristic of a spiral galaxy?
when we take spectra of its stars, they have far less of the heavier elements than the Sun
What is the most striking visual feature of this lenticular galaxy?
it looks like the central bulge of a spiral galaxy but it has no spiral arms.
The new instrument that made it possible for Edwin Hubble to demonstrate the existence of other galaxies in the early 1920's was:
the 100-inch reflector on Mount Wilson
One of the most important observations in the history of astronomy was the one by Edwin Hubble that established that there are other galaxies, quite removed from the Milky Way. How did Hubble show this?
by observing a Cepheid variable in a nearby galaxy and using it to get the distance
Which of the following statements about the different types (shapes) of galaxies is correct?
collisions and mergers between galaxies can sometimes change a galaxy's type (shape)
What type of galaxy is NGC1317? (Use the diagram for Hubble's galaxy classification scheme to help you in answering this question.)
SBa
How does this elliptical galaxy differ in appearance from a spiral galaxy?
There are no visible spiral arms
What features do these visibly different spiral galaxies have in common?
They both have a bright central core surrounded by a disk of spiral arms.
About two thirds of the nearby spiral galaxies (which we can study in more detail) don't have a round central bulge, but instead show
a central bulge with a bar of stars in the middle
