Astro 115 Ch7

If life does indeed exist elsewhere in our solar system it will most likely take the form of

• human beings

• plants

• birds

• microbes or other simple life

Habitability generally refers to an environment capable of sustaining

• human life

• plant life

• microbial life only

• any kind of life

The necessary chemical elements of life should

• only be found on the Earth and Mars

• be widespread in the solar system but not elsewhere in our Milky Way galaxy

• be widespread throughout the universe

• be widespread in our Milky Way galaxy but not in other galaxies

Given that organic molecules need to react in order to produce life, this suggests we should search for worlds in the solar system that have

• either an atmosphere, or a surface or subsurface liquid medium such as water, or both.

• organic molecules on their surfaces

• an atmosphere

• rocky surfaces

The planet Saturn is approximately 10 times farther away from the Sun than the Earth is. Given this, how much sunlight does it receive compared to the Earth?

• 1/1,000th

• 1/10,000th

• 1/100th

• 1/10th

A newly discovered asteroid of the Aten family is found to be 50% closer to the Sun than the Earth is. Given this, how much sunlight does it receive compared to the Earth?

• half as much

• four times as much

• twice as much

• about the same

Photosynthetic life existing on a planet farther from the Sun than the Earth would most likely be

• smaller, less efficient at collecting solar radiation or have a faster metabolism than photosynthetic life on Earth

• identical to photosynthetic life on Earth

• larger, more efficient at collecting solar radiation or have a slower metabolism than photosynthetic life on Earth

• impossible

All of the most likely alternatives to water as a biological solvent are liquids at

• higher temperatures

• lower temperatures

• lower pressures

• similar temperatures

Which of the following is an advantage that liquid water has as a biological solvent compared to other alternatives?

• when it freezes it becomes less dense

• it is a liquid over a wide temperature range and remains liquid at higher temperatures

• it is able to dissolve many things

• all of these are advantages

Which one of the following properties is unique to water?

• it has a high heat capacity

• it is a good solvent

• it is a liquid over a wide temperature range

• it expands on freezing