5.5.3 Hubble's Law

• The formula for Hubble's Law is v = H_0d
• Using Hubble's Law, one can calculate either distance or recession velocity
• In the Hubble's Law formula, \(v\) represents the recessional velocity
• What is the recessional velocity measured in?

  km/s
• The Hubble constant is denoted by the symbol H_0
• The Hubble constant represents the rate of expansion
• Hubble's Law implies that galaxies farther from us are receding faster.


  True
• The Hubble constant describes the rate of expansion of the universe
• What does \(H_0\) represent in Hubble's Law?

  Hubble constant
• Hubble's Law implies that all galaxies are moving away from each other.

  False
• Hubble's Law states that the recessional velocity of a galaxy is inversely proportional to its distance.

  False
• Velocity in Hubble's Law is measured in kilometers per second.


  True
• What does a higher value of the Hubble constant indicate?

  Faster expansion rate
• What formula is used to calculate recession velocity or distance in Hubble's Law?

  $v =$$H_{0}d$
• The Hubble constant is measured in kilometers per second per megaparsec.
• What are the units used for distance in Hubble's Law?

  Mpc
• What does Hubble's Law state about the recession velocity of a galaxy and its distance from us?

  Recession velocity is directly proportional to distance
• The recession velocity of a galaxy increases with its distance from us.

  True
• Hubble's Law is a cornerstone of modern cosmology.


  True
• Match the term with its meaning:

  v ↔️ Velocity at which a galaxy moves away

  H_0 ↔️ Hubble constant; rate of expansion of the universe

  d ↔️ Distance to the galaxy
• The Hubble constant indicates the rate of expansion of the universe.


  True
• What is the meaning of the Hubble constant in cosmology?

  Rate of expansion
• What does \(v\) represent in Hubble's Law?

  Recessional velocity
• The recessional velocity in Hubble's Law is measured in kilometers per second
• Arrange the variables in Hubble's Law from most fundamental to derived:

  1️⃣ Distance (d)

  2️⃣ Hubble constant (H₀)

  3️⃣ Recessional velocity (v)
• The Hubble constant is a key parameter in cosmology
• What are the three variables in Hubble's Law formula?

  v, H₀, d
• What does the Hubble constant (\(H_0\)) represent in Hubble's Law?

  Rate of expansion
• The current estimate for the Hubble constant is 70 km/s/Mpc.


  True
• Hubble's Law states that the recession velocity of a galaxy is directly proportional to its distance from us.

  True
• The Hubble constant is the proportionality constant in Hubble's Law.


  True
• Galaxies farther away recede at a faster rate.
• The formula for Hubble's Law is v = H_0d
• The Hubble constant is measured in units of km/s/Mpc
• What is the significance of Hubble's Law in creating a cosmic distance scale?

  It allows astronomers to calculate distances to far-off galaxies
• Match the cosmological term with its significance:

  Hubble's Law ↔️ Evidence for the expansion of the universe

  Expansion of the Universe ↔️ Supports the Big Bang theory

  Cosmic Distance Scale ↔️ Helps measure distances to galaxies
• Observational uncertainties in measuring galaxy distances can affect the value of the Hubble constant
• What is Hubble's Law about?

  Recessional velocity and distance
• What does the proportionality constant in Hubble's Law represent?

  Hubble constant
• What are some limitations of Hubble's Law?

  Local gravitational effects