BRAINCAKEThe Age of the Universe
If the universe has expanded at a constant rate since the Big Bang, Hubble's law can be used to estimate its age.
Imagine a galaxy now at a distance d, moving away at speed v. If its speed has always been the same, the time t it has taken to reach its current position from the start of the expansion is:
t = d/v
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Key terms in this lesson
- hubble's law
- The recession speed of a galaxy is directly proportional to its distance from us.
- dark energy
- An unknown form of energy, spread evenly through space, thought to be responsible for the accelerating expansion of the universe.
More in Astrophysics and Cosmology
- The Cosmological Principle
- The Doppler Effect and Red Shift
- Hubble's Law
- The Big Bang Theory
- Cosmic Microwave Background Radiation
- Evolution of the Universe
- Dark Matter
- Dark Energy
All 24 lessons in Astrophysics and Cosmology · All OCR A-level Physics topics