⚙️ how
How do astronomers weigh a galaxy?
Quick Answer
They measure how fast stars or gas orbit inside it. The orbital speed reveals the galaxy’s total mass, including dark matter, which is often far more massive than the visible stars.
The Full Story
A galaxy is weighed by studying the motion of stars, gas, and sometimes satellite galaxies around it. If objects near the edge move faster than visible matter alone can explain, astronomers infer the presence of dark matter. This method helped show that galaxies are surrounded by enormous dark matter halos. In the Milky Way, most of the mass is not in stars or gas but in dark matter that cannot be seen directly.
Key Facts
1.Galactic mass is measured using orbital motion
2.Dark matter makes up most of a galaxy’s mass
3.The Milky Way’s visible matter is only a small part of its total mass
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Suggested video title for this topic:
"How do you weigh something you can’t see?"
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