W10 L1 - Galaxy types and features Flashcards
Summarises the shapes of galaxies and the cyclical processes within them
How thick is the Milky Way Galaxy?
About 1,000 light years thick
How far from the center is the Milky Way?
About 28,000 light years
Name two features outside the main disc of the Milky Way
Globular clusters and halo
What embeds the luminous matter in the Milky Way?
Dark matter
What angle is the ecliptic tilted to the Milky Way?
60 degrees
How many spiral arms does our Milky Way galaxy have?
Four (probably, it’s debated)
What are the orbital kinematics of the halo and bulge stars?
Random orientations
What are the orbital kinematics of the disc stars?
Dolphin dive like
How long does the Sun take to orbit the Milky Way?
230 million years
What speed does the Sun orbit the Milky Way?
220 km/s
How do stars recycle material into the galaxy?
Blow material off with planetary nebulae or supernovae
Which has the stronger stellar winds? Large or small stars?
Large
What do supernovae blow out of the galactic disc?
Hot bubbles that condense to form hydrogen clouds and then molecular clouds
What are the 4 steps in the recycling process of a star in a galaxy?
1) Star performs fusion 2) bubble 3) enrichment 4) next generation of star
What wavelength could you use to see bubbles being pushed out of the Milky Way disc?
X-ray
What wavelength would you use to see the H cooled into the galactic plane?
Radio (21cm)
What wavelength and molecule could you use to scan the sky for molecular clouds?
Radio, carbon monoxide
Name two types of nebula
Emission and reflection
What type of nebula is Orion?
Emission
What’s another name for an emission nebula?
Ionisation nebula
Where does star formation in a spiral galaxy happen?
In the spiral arms
Does the halo contain young or old stars?
Old stars
What’s the acronym for galaxy shapes?
ISE
Name the 3 main shapes of galaxies
1) spiral, 2) irregular, 3) elliptical
What is the most common shape of spiral galaxy?
Barred spiral galaxy
What age stars tend to be in elliptical galaxies?
Older mellow chill stars
What type of galaxy are the Magellanic clouds?
Irregular galaxies
What emission nebula is beside the Magellanic Cloud?
Tarantula Nebula
What’s the upper limit on the number of spiral galaxies you might find hanging with each other?
Up to a few dozen
How many elliptical galaxies might you find grouped together?
Hundreds to thousands
