Europa Flashcards
Which missions have gone to Europa
Pioner 10 and 11 - 1973
Voyager 1 and 2 - 1979
Galileo space probe - 1995
New Horizons - 2007
What did the Galileo space probe do?
First orbit of Jupiter and released probe into it
Focused on Europa for two years
What are the 4 largest Moons of jupiter?
Ganyemede
Callisto
Io
Europa
What are the properties of Io?
Highest density
Driest object in solar system
400 active volcanoes
What are the properties of Ganyemede?
Largest moon in SS
Has magnetosphere
Has dark cratered surface and lighter cross cut surface
Salty ocean under crust of ice
What are the properties of Callisto?
Second largest moon
Most heavily cratered object in SS
White spots against dark regions
May have subsurface ocean
How is Europa locked to Jupiter?
Tidally
How many of Jupiters moons are in orbital resonance?
3
How does tidal effect work?
- Each moon receives tug from its neighbours at same point causing more elliptical orbit
- Tidal forces from Jupiter circularise their orbits
- eccentricity of the orbits causes regular flexing which heats the moons interior through friction
What are the properties of Europa?
3122km diameter
Water ice surface
Very smooth
Silicate rock with iron core
Thin atmosphere of oxygen
What are Europa’s surface features like?
Dark streaks crossing it
Resembles sea ice on Earth
When are most of the surface features from?
Past 50 million years
What are the cracks caused by?
tectonic stress and melted and refrozen ice
How big are crustal plates that break up and rides on the surface?
8 miles across plates
Ridges of 1.6 miles wide from a fault in the ice
What is a possible internal structure of Europa?
Iron core + rocky interior
Outer layer of water
What could be the sources of internal heat?
Tidal friction
Radioactive decay
How would the core heat melt the ice?
Conduction from the core - 5 kelvin per km lost in heat
At depth of 30km it would be high enough to melt ice
What could be a source of biogenic elements within Europas oceans?
Hydrothermal systems
Silicate minerals from the rocky core
What formed Europas thin oxygen atmosphere?
Sunlight and charged particles interacting with water on the surface
What is Lake vostok?
Largest sub-glacial lake in Antarctica
Discovered in 1970s
How is it a Europa analogy?
Prescence of fresh water 4km beneath ice
Water temp is around -3c
How does lake vostok stay liquid?
High pressure from overlying ice
Geothermal heat from below
How many sub-glacial lakes in Antarctica?
140
How often and how is the lake water replaced?
Every 13,300 years
Freezing and then carried away by antarctic ice sheet motion as its replaced by other melting ice
What ice cores were drilled to reach the lake?
3600m deep
Halted 100m above lake
What was found in the ice cores?
Microbial life all the way down ice cores
0.5 million yeas old
Found in ice migrating up from the lake
What microbes were found from lake vostok?
- Regular bacteria
- Many cyanobacteria with lots of toxic heavy metals
What did the finding of microbial life in the lake show?
extremely cold, dark environment cut off from nutrients can still support life
What explains Europas induced magnetic field?
Subsurface salt-water ocean that encompasses the whole planet
What was the Galileo spacecraft?
Orbit and entry probe
1989
Orbited Jupiter 34 times before entering it
What are the future missions to Europa?
Jupiter Icy Moon Explorer
Europe clipper
Europa Lander
