Astronomy (part 13) for my love

Based on counting the number of galaxies in a small patch of the sky and multiplying by the number of such patches needed to cover the entire sky, the total number of galaxies in the observable universe is estimated to be approximately

• 100 million

• 1 billion

• 10 billion

• 100 billion

• 1 trillion

Suppose that we look at a photograph of many galaxies. Assuming that all galaxies formed at about the same time, which galaxy in the picture is the youngest?

• the one that is reddest in color

• the one that is bluest in color

• the one that is farthest away

• the one that is closest to us

• the one that appears smallest in size

Which of the following types of galaxies are most spherical in shape?

• spirals

• ellipticals

• lenticulars

• irregulars

Which of the following types of galaxies are reddest in color?

• spirals

• ellipticals

• lenticulars

• irregulars

Which of the following statements about galaxies is true?

• Small galaxies outnumber large galaxies and produce most of the light in the universe.

• Small galaxies outnumber large galaxies but large galaxies produce most of the light in the universe.

• There is an approximately equal number of small and large galaxies in the universe and together they each contribute an equal amount of light.

• Most galaxies in the universe are about the same size as the Milky Way

• Galaxies come in a wide variety of shapes and sizes but are all very blue in color.

Which types of galaxies have a clearly defined halo component?

• spirals only

• ellipticals only

• lenticulars only

• irregulars only

• all but irregulars

Which types of galaxies have a clearly defined disk component?

• spirals only

• ellipticals only

• lenticulars only

• irregulars only

• spirals and lenticulars

Compared to spiral galaxies, elliptical galaxies are

• redder and rounder.

• redder and flattened

• bluer and rounder.

• bluer and flattened.

• always much smaller.

The disk component of a spiral galaxy includes which of the following parts?

• halo

• bulge

• spiral arms

• globular clusters

• all of the above

How does a lenticular galaxy differ from a normal spiral galaxy?

• It has no bulge.

• It has an elongated bulge resembling a bar more than a sphere

• It is flatter in shape.

• It has no gas or dust.

• It has no spiral arms