Venus

Question 1

whats is the mass of venus compared to earth?

Answer 1

0.82 x

Question 2

what is the radius of venus compares to earth?

Answer 2

0.95 x

Question 3

what is the surface gravity of venus compared to earth?

Answer 3

0.9 x

Question 4

what is the mean orbital radius?

Answer 4

0.72 au , almost circular

Question 5

what is the maximum elongation of venus?

Answer 5

48 degrees from sun as seen from earth

Question 6

what is the albedo?

Answer 6

76%, brightest object in sky after sun and moon

Question 7

does venus have phases?

Answer 7

yes, bigger than mercurys’ and can be seen with binoculars.

Question 8

what phase of venus is the brightest?

Answer 8

crescent

Question 9

when is venus visible?

Answer 9

evening or morning.

Question 10

rotation period of venus?

Answer 10

ranges from 22 hours up to 224.7 days

Question 11

what did photographic observations show in 1950s?

Answer 11

a y shaped feature gave a 4 day retrograde (reverse) rotation.

Question 12

what did radar measurements show in 1961?

Answer 12

surface rotated in a period of 243 days and was retrograde

Question 13

why does venus have a high albedo?

Answer 13

clouds of venus reflect sunlight

Question 14

what did spectroscopic measurements in 1930 show?

Answer 14

CO2 major constituent

Question 15

what did radio observations show?

Answer 15

that surface temp is hot about 500 degrees

Question 16

what is the composition of the atmosphere?

Answer 16

96% carbon dioxide
3.5% nitrogen
traces of so2 
water vapor h20
sulphuric acid h2s04 (acid rain)

Question 17

what is the temp at the cloud tops?

Answer 17

-30 degrees

Question 18

what is the pressure at the surface?

Answer 18

90 atmospheres

Question 19

what distances do the sulfuric acid clouds form?

Answer 19

between 48-60 km from ground

Question 20

how is the expected temperature calculated?

Answer 20

Tplanet = TSun (1 − a)^0.25√RSun/2d

Tplanet= expected temp in kelvin of planet
d= distance from sun
a= albedo (a=1 then 100% reflection)

Question 21

why is venus much hotter?

Answer 21

green house gases
visible light penetrates clouds and gets to surface- warmed and re-radiates in the infrared.
re-radiated energy is absorbed and heat is trapped near surface

Question 22

what did mariner 10?

Answer 22

flyby photos of cloud tops taken in ultraviolet showed rapidly moving circulation, only 4 days to circle planet speeds of 360 km/h- retrograde direction

Question 23

what did veneras do?

Answer 23

beneath clouds, landing probes on surface

Question 24

what did veneras find out?

Answer 24

hostile planet
90x pressure that earth at sea level
landscape- heap of stones- sharp edges and smooth
wind speeds sluggish
sunlight casts shadows

Question 25

what did the pioneer venus orbiter do?

Answer 25

moniter cloud motions, while probes recorded data on temp, pressure and composition with altitude

Question 26

what did the magellan do?

Answer 26

detailed radar map of entire surface- no magnetic field

Question 27

what did venus express do and when launched?

Answer 27

nov 2005 arrived april 2006 found evidence for past oceans and confirmed presence of lightning by studying atmosphere and clouds

Question 28

what did venera 9 show?

Answer 28

scree on a hill (15-25 degrees) slope, field of flat boulders,separated by sharp stones and dust

Question 29

what did venera 10 show?

Answer 29

older more weathered, smoother surface | gamma ray spectrometer revealed volcanic rock, basalt

Question 30

what did venera 13 show?

Answer 30

phoebe regio: rock-strewn plain, with outcrops and patches of dark, fine-grained material. evidence of chemical erosion. soil showed basalt and potassium

Question 31

what did venera 14 show?

Answer 31

less-fine grained material regular layers of rocky,broken plates basalts similar to earths seabed

Question 32

average density of venus?

Answer 32

5.3 g/cm^3

Question 33

which features reflect better?

Answer 33

a hard flat surface better than powdered one | earth facing slope better than oblique

Question 34

what was the pioneer venus the first to attempt 1978?

Answer 34

orbit radar around venus

Question 35

how did the pioneer venus take its recordings?

Answer 35

using radar altimeter which bounced microwaves off surface. Built up a map in strips as venus rotated. mapped 93% of surface- resolution of 50km

Question 36

what are the 3 general types of terrain on venus?

Answer 36

1: rolling plains (65%) 2: highlands (8%) 3: lowlands (27%)

Question 37

Describe features of rolling plains

Answer 37

lying within 500m of mean level, numerous craters and circular basins, some filled with lava. Some volcanic, some impact large and shallow.

Question 38

what are the three major regions of highlands?

Answer 38

ishtar terra, aphrodite terra, beta regio

Question 39

what are the features of ishtar terra?

Answer 39

size of australia. lofty plateau (3km). several mountains, including maxwell montes which is highest of venus volcanic region

Question 40

what are the features of aphrodite terra?

Answer 40

size of africa, rough and broken mountains

Question 41

what are the features of beta regio?

Answer 41

two large shield volcanoes, rhea and theia mons. 4km high and lie on fault line.

Question 42

what do the valley and trench systems imply?

Answer 42

tectonic activity played a role in formation of these regions

Question 43

why does water vapour increase green house gases on venus compared to earth?

Answer 43

no seas to dissolve co2 it in.

Question 44

what did eventually happen with the water?

Answer 44

dissociated into hydrogen which escapes and oxygen which reacted with rocks

Question 45

what is a transit of mercury and venus?

Answer 45

because closer to sun, get between earth and sun on occasion and can be seen as dark discs moving across solar surface

Question 46

why is there more opportunities to see a transit of mercury?

Answer 46

orbits the sun more quickly

Question 47

why does the geometric alignment of mercury only occur every 7 years in may or november?

Answer 47

the plane of mercurys orbit is tilted by 7 degrees with respect to that of earth

Question 48

what is the orbital plane of venus with respect to earths orbit?

Answer 48

inclined by 3.4 degrees so takes 8 years in pairs in june or december, each pair separated by 106 or 121 years

Question 49

what can transits be used for?

Answer 49

to measure parallax angle