How did we discover that the Universe is Expanding? What does
it mean that it is expanding? This lecture introduces Hubble's Law,
the observational evidence that the Universe is systematically
expanding. As galaxies get more distant from us, the apparent speed
of recession gets larger in proportion. The proportionality is the
rate of expansion, called t ... Show More
Feb 2006
Lecture 32: Space, Time, & Gravity: General Relativity
What is gravity? Newton left that question unanswered when he formulated
his inverse square law of the gravitational force, framing no hypothesis
for what agency transmits gravity, only asserting it was an action
at a distance. Einstein brought gravity into relativity by answerin ... Show More
47m 56s
Feb 2006
Lecture 31: A Tale of Two World Views: Special Relativity
What are space and time? To begin our exploration of the evolving
Universe, we must first understand what we mean by space and time.
This lecture contrasts the Newtonian view of the World, with its
absolute space and absolute time, with that of Einstein, who showed
that space and ... Show More
43m 3s
Jun 2009
Telescopes that Rocked Our World
This year marks the 400th anniversary of Galileo’s use of the first telescope. On this week’s show, we reflect on how telescopes have shifted our perspective on how small we are in size, space, and time. We also discuss how they help astronomers discover new and interesting aspec ... Show More
56 m