Unit 10 Topic 3.4 In Our Backyard Flashcards

Question

Conditions on Mars Today | DISTANCE, SIZE, AND SURFACE TEMP VS. EARTH

Answer 1

* Mars = 232 million km away from sun, while Earth = 148 million km away * Mars diameter = 6,792 km; much smaller than Earth * The average surface temperature on Mars hovers around -65°C, a stark contrast to Earth's milder 15°C.

Answer 2

* Mars's atmosphere, comprising about 95% carbon dioxide, is **significantly thinner than Earth’s**, with an **atmospheric pressure at the surface less than 1% of that found on our planet**. * These low-pressure conditions would cause liquid water to evaporate at the surface rapidly. * Additionally, **Mars lacks an active magnetosphere**, leading to high levels of radiation at the surface.

Answer 3

* Likely had a **thicker atmosphere** and a **magnetic field**, which could have helped shield the surface from radiation. * Evidence suggests that **liquid water once flowed on its surface** and may have even formed **oceans**. * **Much of that water is now frozen at the poles.** Mars was also more geologically active in the past, as evidenced by its numerous inactive volcanoes and possible tectonic activity

Answer 4

* YES * Early Mars had all the conditions necessary for life to evolve: liquid water, a source of organic materials from meteorites, energy from the sun and perhaps from active volcanic heat sources. * In addition, all the life-essential "**CHNOPS**” have now been identified on the surface of Mars.

Answer 5

* **MISS**: Microbially-induced sedimentary structures. * In addition to stromatolites, microbes can cause **wrinkles** on the surface of sediments called Elephant Skin Textures * Images taken by the Curiosity Rover on a potentially dried lake that may have undergone seasonal flooding billions of years ago. * Some of the features on the image resemble MISS fossils from the Precambrian found on Earth today

Answer 6

to find **biosignatures** or convincing **fossils** that date to this period on Mars

Answer 7

Although Mars today is very challenging for life, **it still possesses essential life elements (CHNOPS)** and plenty of **water** frozen at the poles or within the Martian regolith, a blanket of unconsolidated loose material covering the rocky surface.

Answer 8

* Liquid water might still occur in the subsurface close to old volcanic centers warm enough to melt the ice. * The water would be very salty, but halophile Martian microbes might survive in such conditions.

Answer 9

* Possibility of a subsurface biosphere comes from analyzing **methane**, a gas commonly produced by microbial activity on Earth. * The Curiosity Mars rover **discovered that methane appears to have a *seasonal cyclicity in Mars's atmosphere***, with more gas released during the summer months * Could this be evidence of a subsurface colony of methanogenic (methane-producing) microbes that are more active when the Martian surface warms during the summer? * It is possible, but it is important to note that rocks rich in the mineral Olivine (common on Mars) can react with liquid water to produce methane (Figure 13-right).

Answer 10

1. Mars evolved a **biosphere that is now completely extinct** 2. Mars' **biosphere still exists but in very restricted locations** 3. **Life never evolved on Mars**

Answer 11

* Icy moons are a class of natural satellites with surfaces mostly composed of ice. * We will focus on two icy moons: **Jupiter’s Europa** and **Saturn’s Enceladus.**

Answer 12

The surface of Jupiter’s moon, Europa, exhibits a complex network of ridges and cracks and a notable absence of craters, suggesting a degree of geological activity

Answer 13

* As Europa orbits around Jupiter, the gravitational influence induces tidal flexing on the moon, akin to a baker kneading dough. * This gravitational kneading process is **hypothesized to generate heat within Europa's rocky core**. * Consequently, **this internal heat is believed to have facilitated the formation of a saline ocean beneath Europa's icy crust. ** * The visible ridges and cracks on the moon's surface indicate dynamic movements within this subsurface ocean.

Answer 14

* While other moons in the Jovian system, such as Ganymede and Callisto, may also harbour subsurface oceans, **it is thought these are situated between layers of ice** * In contrast, **Europa's ocean is believed to have *direct contact with its rocky interior*** * This direct interface is of particular interest due to the potential for chemical processes that may produce a variety of substances necessary for the evolution of life

Answer 15

* Enceladus, a moon of Saturn, has provided clear evidence of a subsurface liquid ocean below its south pole * These cracks radiate heat, with temperatures recorded by Cassini at -80°C, 120°C warmer than the rest of the surface (detected amines/amino acids, phosphorous) * The water was salty, and the composition was very similar to that being released at hydrothermal vents on Earth.

Answer 16

* As with Europa, tidal flexing is probably the mechanism that has produced a subsurface liquid ocean in Enceladus. * It has been suggested that the **heat generated by this process in both moons may be sufficient for the formation of hydrothermal vents on the surface of their rocky cores**, potentially supporting a microbial chemosynthetic ecosystem akin to those found in Earth's oceans

Answer 17

* Titan, a moon of Saturn, is **the only moon with a thick atmosphere**; 96 % nitrogen, the rest predominantly methane. * It is also the **only other object with stable bodies of liquid on its surface**. * In Titan's case, **this liquid is methane (CH4) and Ethane (C2H6), gasses on Earth but liquids in the extreme cold (around -179°C) on Titan**. * Hydrocarbons cycle through Titan, similar to how water cycles on Earth. Methane is evaporated from the moon's surface, forming clouds that generate liquid methane rain that returns to the lakes in methane river systems.

Unit 10 Topic 3.4 In Our Backyard Flashcards

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