Unique galactic insights

1. How many galaxies do scientists estimate to exist in the universe?

Up to 10 million

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1 million – 1 billion

1 billion – 100 billion

100 billion – 1 trillion or more

2. What proportion of an average galaxy’s mass consists of regular matter like stars and gas?

Less than 5 percent

21 percent

67 percent

100 percent

3. Scientists occasionally categorize galaxies into various types, some of which were established by Edwin Hubble in 1926. Which of the following is NOT a usual classification?

Spiral galaxies

Elliptical galaxies

Lenticular galaxies

Blended galaxies

Irregular galaxies

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4. Centaurus A, a galaxy approximately 12 million light-years from Earth, is peculiar in which aspect?

It possesses lobes protruding from its center, perpendicular to its disk, created by energetic jets released by the supermassive black hole at the galaxy’s core

It’s an elliptical galaxy featuring spiral arms, indicating that it has merged with a spiral galaxy

It is classified as a starburst galaxy, which has recently experienced an exceptionally vigorous phase of star formation

All of the above

6. Which of the following techniques is NOT utilized to determine distances to other galaxies?

Evaluating the luminosity of stellar explosions termed “supernovae”

Estimating the visible size of galaxies

Assessing the travel time of radio waves to and from the galaxy, additionally known as radar ranging

Determining the velocity at which a galaxy is receding from us

Analyzing random noisy variations in images of galaxies

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9. Lenticular galaxies represent a mid-type of galaxy situated between ellipticals and spirals: They possess substantial stellar disks, yet lack spiral arms. Which of these lenticular galaxies differs from the rest?

NGC 4550

NGC 4866

NGC 5308

NGC 5866

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10. The supermassive black hole at the heart of our galaxy, Sagittarius A*, is predominantly inactive, though it hasn’t always been like this. When was the last occasion our black hole showed considerable activity?

The Middle Ages, when early astronomers thought celestial events were signs of death

Approximately 6 million years ago, when the first hominids began to stand upright

Around 200 million years ago, when Earth’s continents were united in the supercontinent Pangea

About 4.9 billion years ago, prior to the formation of Earth

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