Lecture 3 Flashcards
(24 cards)
How many stars are in the milky way galaxy?
200 million-250 billion
What are some of the components of the milky way?
Planets gravitating around stars, nebulae, interstellar dust, solar systems.
What do things gravitate around in the milky way?
The centre of the galaxy-consists of closely spaced stars and dense dust.
What is the diameter of the milky way and it’s mass?
80 000 light years, and 750 billion times the mass of the sun
What are the four arms of the milky way galaxy?
Perseus, Cygnus-Orion, Sagittarius and Centaurus
What is the “local group?”
The group of galaxies in relatively close proximity to us-ours is part of the Virgo Superchain
Who discovered the existence of red and blue shifted stars?
Vesto Stipher
What does it mean that a star is blue shifted/red shifted?
Blue shifted- the very few galaxies that are moving towards us
Red-shifted- galaxies moving away from us
How did we find out the existence of red and blue shifted stars?
Once we invented telescopes that were able to see infrared waves.
What did Edwin Hubble discover?
The farther away a galaxy is, the faster it is receding. This proves that the Universe is EXPANDING
How can we calculate the universe’s age?
Using it’s rate of expansion.
When did the process of universe expansion begin?
13.7-13.8 billion years ago (before this, it’s mass was concentrated into a very small space)
What is the Big Bang Theory?
Theory that explains the initiation of universe expansion.
Which two space craft gave experimental confirmation of the Big Bang?
COBE and WMAP
What did COBE (Cosmic Background Explorer) measure in 1992?
Discrete temperature fluctuations in the deepest regions of space.
What did WMAP measure in 2002?
Plotted the oldest light in the universe.
What are the Nebulae?
Concentrations of interstellar gas and dust.
How are Nebulae formed? (3 Ways)
1) Concentration of small sized material
2) Explosion of a star or other celestial body
3) Collision between 2 or (rarely) more celestial bodies
What is the Eagle Nebulae?
The most spectacular nebula we know of- regarded as a typical example of “the birthplace of stars”
What does the Eagle Nebulae consist of?
Dust, gases (hydrogen and helium), and vapors which are referred to as “interstellar fog”
What are stars?
Massive celestial bodies consisting of ionized gas (hydrogen and helium)
What is gravitational contraction?
Due to a stars mass being so big, they are constantly in danger of shrinking.
What are some of the stars that are smaller than the sun?
Sirius B, Proxima and Centauri
What are some stars that are bigger than the sun?
Rigel and Beetle Juice
