LANGA HIGH SCHOOL

1
LANGA HIGH SCHOOL

• AIMSSEC PRESENTATION
• 21 JUNE 2005

2
THE EXPANDING UNIVERSE

• Many scientists explain how the universe began
  using a theory called the BIG BANG THEORY.
• This occurred after an Astronomer called Edwin
  Hubble discovered that the galaxies we see in all
  directions are moving away from the Earth.

3
Who is Edwin Powell Hubble
Born in 1889 in Marsfield, Missouri
1910 received Undergraduate degree in Law under a
Rhodes Scholarship at Oxford University .
Later, in 1917 he changed his mind and completed
his Ph.d. in Astronomy at Chicagos Yerkes
Observatory
In the 1920s, Edwin P. Hubble discovered a
relationship that is now known as Hubble Law.
4
USING Hubbles own data
5
Hubble's Law

• The Velocity of a galaxy is proportional to its
  distance from us.
• The more distant the galaxy, the faster it was
  moving from us
• V H0 D Where
• V is a velocity of galaxy (km/sec)
• H0 is the proportionality constant
• D is the distance to the galaxy (Mpc)
• Mega parsec (Mpc) 3.26 million light years

6
Estimating the Age of the Universe

• If you know the speed of an object, and the
  distance it has traveled you can calculate the
  time it must take to travel the distance
• FORMULAR Velocity Distance
• Time

7
Hubble Constant (H0)

• The Hubble constant is a measure of the current
  expansion rate of the universe.
• Simple way to estimate the value of H0 is to draw
  a straight line that best fits the points on the
  graph, and measure the slope of the line.
• If the Universe has been expanding at a constant
  speed since the Big Bang, the universe age would
  be simply 1/H0

8
Calculations from Data

• Slope Velocity(km/sec) 1800 520
• Distance (Mpc) 3.45
• Convert the Units Velocity (km/year)
• Distance (km)
• 5.358 X 10-10
• Time 1/ 5.358 X 10-10
• 1.86 X 109
• In more familiar units, astronomers believe that
  1/Ho is between 12 and 14 billion years.

9
THANK YOU