Exam 20: Astrobiology: Life on Other Worlds

Why is it believed that life cannot evolve on a planet that orbits a spectral type A, B, or O star?

All life on Earth is based on carbon chemistry.

Explain the times, periods, and events that refer to life's evolution leading to human life on Earth.

____________ is a segment of a chromosome that controls a specific function.

Our civilization's lifetime needs to be considered in obtaining a realistic estimate of the number of civilizations that we can communicate with in our galaxy.

DNA is important to a cell because

The Miller experiment succeeded in creating ____________.

What part of the radio spectrum is thought most likely to be successful for communication with other civilizations? Why?

How does the likelihood of the survival of technological societies restrict the number of civilizations with which we might communicate?

The Miller-Urey experiment created synthetic DNA.

How can we select stars whose planets are likely homes for life?

Evolution is random.

The Viking landers searched for life on ____________.

In the Arecibo message shown above, the sky blue line leads to a sky blue letter S and its mirror image, which represent

As far as we know all forms of life on Earth use ____________ as a medium for chemical reactions.

Earth has not been visited by aliens, according to your textbook.

Chemical evolution concentrated the various smaller molecules into the more stable forms.