Astro 7 Flashcards
Who was Giovanni Schiapparelli and what did he observe on Mars in the 1870s?
He was the director of Brera Observatory in Italy and observed ‘caneli’ (channels) on Mars, which some thought were evidence of life or civilization.
What was Percival Lowell’s belief about Mars?
He believed that the ‘canals’ on Mars were built by intelligent beings.
What did improved telescopes in 1909 reveal about Mars’ canals?
They revealed that no constructed canals existed on Mars.
By early 1900s, what conclusion was made about advanced civilizations in the Solar System?
It was considered unlikely-to-impossible that advanced civilizations existed anywhere else in the Solar System, though microbe life was still possible.
What are the key requirements for a habitat capable of supporting life?
Heavy elements (O, C, H, N, P, S), a protective shield (atmosphere or liquid), energy source, liquid water (or substitute), environmental stability, a surface, and possibly a moon.
Why is water considered ideal for life?
It has a large liquid temperature range (0°C to 100°C), is a polar molecule (good for dissolving other molecules for cell chemistry), and ice floats on liquid water.
Which locations in the Solar System have shown evidence of water or potential for it?
Europa, Enceladus, Callisto (outer solar system), Earth’s Moon, and Mars.
What did the Galileo satellite find about Europa’s surface?
A young, cracked surface with water ice, suggesting an ocean beneath the ice layer.
What chemical may provide energy for life on Europa?
Hydrogen peroxide (H₂O₂), which breaks down into oxygen, supplying a potential energy source for life.
What evidence supports the possibility of life on Enceladus?
Cassini detected plumes of water vapor and complex organic molecules (>200 amu) erupting from its surface.
How was water on the Moon confirmed, and why is it important?
2010 lunar missions (LCROSS, LRO) detected water ice and volatiles. Water is valuable for future exploration (drinking and fuel).
What new discovery was made about water on the Moon in 2018?
OH/H₂O was detected everywhere on the lunar surface, suggesting the role of solar wind and a potential for widespread water.
What did Mariner 4’s 1965 flyby reveal about Mars?
Mars is arid, cratered, has little atmosphere, and no magnetic field; polar ice caps were observed that change seasonally.
What surface features suggest past water on Mars?
Dry river beds, channels, crater lakes, sedimentary rocks, and minerals that only form in water.
What did the Mars Phoenix Lander confirm in 2008?
Water ice exists just below the surface of Mars.
What did the Curiosity rover discover on Mars?
Clay minerals (formed in water), evidence of ancient rivers and lakes, and essential life elements (S, N, H, O, P, C).
Where on Mars is life most likely to be found, and why?
Underground, several meters below the surface, due to harsh surface radiation (no magnetic field or thick atmosphere).
What did the Viking missions’ ‘labelled release experiment’ show, and why is it controversial?
It recorded increased CO₂ when Martian soil was exposed to water and oxygen, possibly indicating life, but results remain debated.
What is sublimation, and why is it relevant to Mars?
Sublimation is when a solid turns directly to a gas. On Mars, CO₂ ice sublimates seasonally, affecting polar ice caps.
What is the current consensus about the potential for life on Mars and its moons?
Mars has strong evidence for water (mostly as ice), conditions suitable for life existed in the past, and some moons like Europa and Enceladus may have suitable conditions for life today.
