Mercury Flashcards
which planets are terrestrial planets?
mercury, venus, earth, mars
which planets are inferior planets? why?
mercury and venus, they orbit the sun closer than the Earth.
What is the mass of mercury compared to earth?
0.555 x
what is the radius of mercury and the radius compared to earth?
2440 km
0.38 x
what is the surface gravity compared to earth?
0.38 x
what is the albedo of mercury?
9%
what is the elongation of mercury? what does this have to do with visibility?
28 degrees
only seen in twilight and not black sky
does mercury have phases ?
yes but 1/140th apparent size of moon on the sky
how many days does it take mercury to orbit the sun?
88 days
what is the mean orbital radius of mercury ?
0.39
what is the eccentric orbit of mercury?
perhelion 0.308 AU (46 mil km)
Aphelion 0.467 AU (70 km)
does mercury keep the same face towards the sun? yes or no and why?
no, disproved by W.E howard 1962.
Radio observations showed warm side (sunward) 400 degrees as expected but dark side was -170 degrees cold. Not as cold as if never faced sun.
what is the rotation period of mercury in days?
59 days
why does mercury make 3 rotations every 2 orbits? explain
rotation period is exactly 2/3 of orbital period. Caused nu combination of elliptical orbit and asymmetric planet density
what is the implications of perihelion because mercury is denser on one side?
tidal forces will try to keep the denser side facing towards or away from sun at perihelion.
tidal forces balanced, no tendancy to slow rotation down to synchronous
why did mercury’s spin slow?
tidal forces tugged rotation and slowed it down. If orbit was more circular- synchronous rotation.
what did mariner 10 reveal in regards to craters?
more widely separated with more smooth space between them. Less surface gravity on mercury than moon so ejecta travels more.
what did mariner 10 reveal in regards to extensive and prominent cliffs (scarps)?
they were not seen elsewhere- caused by shrinking of crust after hardening, making it shrivel and crack
Mariner 10 revealed the large impact crater on mercury. What is its name and what its its features?
Caloris Basin. concentric rings around it.
when does caloris basin point directly towards the sun?
every other perihelion
what may the caloris basin of caused?
the one side of mercury being denser
what is the weird terrain?
rippled appearance may of been created by seismic waves.
because mercury has a high overall density, what could this mean?
large dense core like earth that is partially liquid
what is the magnetic field of mercury compared to earth ?
1%
does mercury have an atmosphere?
no atmosphere because gravity is too low and too hot
when was the messenger launched?
3 august 2004
what did messenger show?
improved surface, new details of caloris basin. discovery of volcanoes.
when did the messenger crash into mercury?
april 2015
