Mastering astronomy Assignment 2

Astronomy has shown us that the Earth

• is the only planet in the universe with advanced life

• occupies a special location in the universe so that life elsewhere is unlikely

• is just one planet orbiting an ordinary star in a vast universe

• is the only planet in the universe with any kind of life

For most of human history it was believed that the Earth was at the center of the universe. This idea is referred to as

• stellocentric

• egocentric

• geocentric

• heliocentric

A habitable world is defined to be one that

• has an atmosphere

• has conditions suitable for life

• is identical to the Earth

• is in orbit about a solar-type star

Extraterrestrial life elsewhere in the universe

• will be completely different than life on Earth

• will be unrecognizable

• will be identical to life on Earth

• could be similar to life on Earth or might be completely different

Astronomy has shown us that the fundamental laws of physics are

• completely random and unpredictable

• different on other planets in our solar system

• the same everywhere in the universe

• the same in our solar system but different beyond the solar system

The fact that the life on Earth seems to have appeared quite rapidly suggests that life

• can arise on most habitable worlds

• on any kind of planet is inevitable

• can only appear soon after a planet forms

• is only possible on Earth-like planets

The discovery of any kind of life beyond the Earth would:

• only be on interest to biologists

• be of interest to all scientists, but of little interest to the wider public

• be of no interest to anyone at all

• cause a profound change in perspective of the whole of humanity

The molecular building blocks of life have been found

• on the Earth and in meteorites

• only on the Earth

• on the Earth, in interstellar clouds, and in meteorites

• on the Earth and on Mars

Which three branches of science are most important in our study of life in the universe?

• physics, mathematics, and astronomy

• astronomy, planetary science, and biology

• planetary science, biology, and mathematics

• biology, mathematics, and physics

The discovery of extrasolar planets indicates that planets around other stars are

• common

• nonexistent

• all Earth-like

• relatively rare

Biologists have found that life on Earth can

• survive over only a very narrow range of environmental conditions

• only survive on the surface of the Earth

• survive only in the presence of sunlight

• survive over a wide range of environmental conditions

Humanity has been thinking about the possibility of extraterrestrial life

• throughout human history since the time of the ancient Greeks

• since reports of canals on Mars were first made in the 1870's

• since the first reports of unidentified flying objects in the 1940's

Extraterrestrial life is defined to be

• advanced life forms that have visited the Earth

• life found beyond the Earth which is based on the same biology and chemistry as life on Earth

• advanced life found on Earth-like planets around other stars

• any kind of life found beyond the Earth

The portrayal of nearly all aliens in movies and on TV as being humanoid is

• realistic because the human form has several unique qualities that make it a good choice for any advanced civilization

• probably unrealistic because the human form is most likely a result of the particular conditions and events that occurred on the Earth

• based on the fact that it would be impossible for us to understand anything that wasn't very similar to a human

• based on the fact that the human form is the only possible form for an advanced civilization

If life exists on Mars today it will most likely be found

• everywhere—on the surface, beneath the surface, and in its atmosphere

• beneath the surface

• on the surface

• in its atmosphere