Chp 2: Age and Size of the Universe Flashcards
How do we measure distances in space (2 different units of measure)?
Light-years and parsecs
Explain how you can use trigonometric parallax to tell the distance of nearby stars
relies on an object appearing to be at a different place relative to the background, depending on your viewpoint.
What is our nearest neighbour galaxy as found by Hubble?
Andromeda galaxy (spiral)
What is the Hubble law? Explain the terms? V = Hd
where v is the speed expressed in kilometres per second, d is the distance of the star/galaxy away from Earth in parsecs (1 parsec = 3.26 light years), and Ho is the ‘Hubble constant’. Ho is actually the speed of expansion of the Universe.
What are the 4 ways to determine distance?
- Trigonometric Parallax (up to 500 ly)
- Main-Sequence Fitting (500- 500 million ly away)
- Cephid Technique (500- 500 million ly away)
- Hubble’s Law (Beyond 500 Million ly)
Will the Milky Way ever crash with the Andromeda galaxy?
yes, the Andromeda Galaxy is hurtling toward the Milky Way Galaxy at something like 500,000 km/hour, and they are expected to crash (or merge?) in about 3 billion years.
When discussing the true brightness of a star, we refer to its ______ brightness.
intrinsic
Our galaxy is
A spiral galaxy
When discussing the brightness you see of a star from Earth, we refer to its ______ brightness.
apparent
Chart to relate the luminosity of stars to temperature
Hertzprung-Russell Diagram
Cepheids
‘marker stars’ that have a special property: they have a pulsing brightness that peaks with absolute regularity (its ‘period’), which is completely related to the star’s brightness.
The big three galaxies in the Local Group
- Andromeda Galaxy (largest)
- Milky Way Galaxy
- Triangulum Galaxy (smallest)
Orion Arm
is a minor spiral arm of the Milky Way Galaxy
