Hubble's law | Scale of the universe | Cosmology & Astronomy | Khan Academy | Summary and Q&A

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November 24, 2010
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Hubble's law | Scale of the universe | Cosmology & Astronomy | Khan Academy

TL;DR

As the universe expands, objects move away from each other at velocities proportional to their distance.

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Questions & Answers

Q: How does the expansion of the universe affect the distances between objects?

The expansion of the universe causes objects to move away from each other, increasing the distances between them.

Q: Why do objects further from Earth move away faster?

Objects further from Earth move away faster because they not only experience the general expansion of the universe but also the cumulative expansion from other objects in between.

Q: Can the expansion of the universe be visualized?

Yes, the expansion can be visualized as points on a grid or the surface of a sphere moving away from each other.

Q: How do we know that objects are moving away from each other?

Scientists can observe the redshift of objects, which indicates that they are moving away, and by comparing the redshifts of different objects, they can determine their relative velocities.

Summary & Key Takeaways

  • Every interstellar object in the universe is moving away from Earth due to the expansion of the universe.

  • The further an object is from Earth, the faster it is moving away.

  • The expansion can be visualized as points on a grid moving away from each other, or the surface of a sphere expanding.

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