Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
21 Cards in this Set
- Front
- Back
|
What are the types of stars?
|
There are seven main types of stars. In order of decreasing temperature, O, B, A, F, G, K, and M.
O and B stars are uncommon but very bright; M stars are common but dim.. An easy mnemonic for remembering these is: "Oh be a fine girl, kiss me." |
|
|
Distance to Nearest Spiral Galaxy
|
2,000,000 light years
|
|
|
Distance to Most distant galaxies known
|
13 billion light years
|
|
|
how many km per Mpc? m per Mpc? cm per Mpc?
|
3.08 times 10 ^ 19
3.08 times 10 ^ 22 3.08 times 10 ^24 |
|
|
Angular/orbital period
|
P = 2 pi R/velocity of rotation
|
|
|
Probability
|
Target area/Total area
a.) One target in one hit anywhere in the other whole target = Target area/Total area b.) One Target in one hit ALL targets in the other (times the # of targets) c.) ALL targets in one hit all TARGETS in the other (times the Number of Targets in the other) |
|
|
REdshift and distances
|
D (now) = D (then) (z+1)
|
|
|
Redshift and TEMPERATURE
|
T (now) = T (then) / (z+1)
|
|
|
Redshift and Volume
|
V (now) = V then ( z+1) ^3
|
|
|
Redshift and Density
|
ρ (now) = - ρ (then) / (z +1) ^3
|
|
|
Proportional Redshifts
|
z = 0.1 - about a 1.25 BLY (nearest quasar)
z = 1 - about 7.25 BLY or half the age of the universe (farthest quasar) z = 5 about5 BLY z = 10 - about 13.2 BLY z = infinite - about 13.7 BLY |
|
|
CMB redshift
|
z = 1100
|
|
|
Nearest star
|
4 LY
|
|
|
Nearest Galaxy cluster
|
Virgo Galaxy cluster - (really the core cluster of the supercluster that our galaxy group (local) belongs to)
- 59 MLY |
|
|
What galaxy group do we belong to?
|
the Local Group
|
|
|
Closest galaxy group
|
M81 - 11 MLY
|
|
|
Mass of the MW
|
3.6 × 10 ^41 kg
|
|
|
- Flux=F=
|
Energy emitted per second per area…
|
|
|
ionization capability probs
|
number of photons
number of protons COMPARE Number of Photons E TOTAL (4 σ T ^4/c^3) divided by E of one photon (if you know the λ... then E = hν where v = c/λ so E (photon) = hc/λ NUMBER Of Protons ρ (matter)/ mass of proton = # of protons where ρ (matter) = total mass/ total volume (4/3 pi r ^3) |
|
|
Volume
|
4/3 pi r ^3
|
|
|
critical radiation density
|
Ώ (rad) = 4σT^4/c^3
important for the calculation of the number of photons and the number of protons in the early universe ... |
