Dwarf Galaxies and Satellite Systems

The Milky Way is not alone — it is surrounded by a whole family of smaller satellite galaxies. Meet our nearest galactic neighbors, including the Magellanic Clouds visible from the Southern Hemisphere, and learn about the galaxy currently being torn apart by our own.

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5–10 min

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Q1 Question 1 of 10

What is the most common type of galaxy in the universe?

Spiral galaxies like the Milky Way Giant elliptical galaxies Dwarf galaxies Lenticular galaxies

Q2 Question 2 of 10

Approximately how many known satellite galaxies does the Milky Way have?

Exactly 2 About 60 About 1,000 None — the Milky Way has no satellite galaxies

Q3 Question 3 of 10

How far away is the Large Magellanic Cloud (LMC)?

About 2,500 light-years away — just inside the Milky Way About 2.5 million light-years — about the same as Andromeda About 160,000 light-years away About 1 billion light-years away

Q4 Question 4 of 10

What was historically significant about Supernova 1987A?

It was the first supernova ever photographed with a camera It was the nearest supernova observed in modern astronomical history, occurring in the Large Magellanic Cloud It was a supernova that destroyed a dwarf galaxy entirely It was the most powerful supernova ever observed, outshining an entire galaxy cluster

Q5 Question 5 of 10

When is the Large Magellanic Cloud expected to merge with the Milky Way?

In about 100 million years In about 2.4 billion years In about 10 billion years Never — the LMC is moving away from the Milky Way

Q6 Question 6 of 10

What is happening to the Sagittarius Dwarf Spheroidal Galaxy right now?

It is being pushed away from the Milky Way by dark matter pressure It is colliding head-on with the Milky Way's central black hole It is being torn apart by the Milky Way's gravity, and its stars are forming a stream that wraps around the entire galaxy It is leaving the Local Group and escaping into intergalactic space

Q7 Question 7 of 10

Why are dwarf spheroidal galaxies particularly useful for dark matter research?

They are so small that dark matter is easier to detect at close range They have very high dark matter fractions — dark matter makes up a much larger proportion of their total mass than in large galaxies They contain a special type of star that makes dark matter visible They rotate so slowly that the effects of dark matter are amplified

Q8 Question 8 of 10

From which hemisphere of Earth are the Magellanic Clouds visible to the naked eye?

The Northern Hemisphere Only from the equator The Southern Hemisphere They are not visible without a telescope from any location

Q9 Question 9 of 10

How far away is the Small Magellanic Cloud (SMC)?

About 10,000 light-years — inside the Milky Way's disk About 200,000 light-years About 2 million light-years — roughly the same as Andromeda About 1 billion light-years

Q10 Question 10 of 10

How did the Milky Way grow more massive over its history?

By collecting interstellar gas from beyond the Milky Way's disk without any mergers Partly by absorbing dozens of smaller dwarf galaxies through gravitational capture and tidal disruption By converting dark matter directly into stars over billions of years By receiving material ejected from the Andromeda Galaxy across intergalactic space

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