Astropedia

Intended for all audiences, this textbook is an introduction to the nature of the universe. Use it to research or review our solar system, stars, galaxies, and the history of the universe. Each chapter has a set of corresponding homework questions.

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Articles related to: Mars  Read article

1. Climate Change on Mars  Read article

The discovery of ancient riverbeds on Mars raises exciting questions about Mars and our own planet. For rivers to exist, the climate must have been different in the past. Why did the climate change? What was the ancient Martian climate like? Could the same thing happen to our planet?

2. Polar Caps of Mars  Read article

Like on Earth, both Martian poles have permanent deposits of ice. Scientists once thought the southern polar cap is composed of mostly frozen carbon dioxide (dry ice), but recent measurements of the polar temperatures indicate both permanent caps are mostly H2O ice, with some CO2<...

3. A Close-Up View of Mars  Read article

The morning of July 20, 1976, dawned cold and clear on a deserted, rocky plain called Chryse, on the planet Mars. This particular morning was seven years to the day after the first humans had walked on the Moon. The dawn temperature on Mars was around -84 °C (-120 °F), but by afternoon th...

4. Life on Mars  Read article

For over 100 years, one of the greatest mysteries in Solar System Science has remained: Is there life on Mars? While several tantalizing results hint at the possibility of microbial life, no incontrovertible evidence exists. While we can't answer this profound question definitively, modern eviden...

5. Early Studies of Mars  Read article

In its orbit around the Sun, Mars comes within 56 million kilometers (35 million miles) of Earth - closer than any other planet but Venus. Because it’s farther from the Sun than the Earth, its sunlit side faces Earth when it is closest to us. (You can draw a simple diagram of the two orbits...

6. Basic Rock Types  Read article

A rock is a combination of two or more minerals that have either been fused together by heat or pressure, or that have cooled out of a liquid together. The minerals are nothing more than individual grains of a constant chemical composition, and they usually have a crystal structure. As an example...

7. Normal Atmospheric Composition  Read article

Carbon dioxide is supposed to be the "normal" atmospheric composition of a terrestrial planet. This generalization might seem wrong at first, because only a couple of planets follow it. Mars and Venus have CO2 atmospheres, but the Moon and Mercury have no significant atmosphe...

8. Water on Mars  Read article

One of the most exciting revelations from the mapping of Mars in the 1970s was the discovery of ancient, dry riverbeds. We know these channels were carved by water because they have the same structure as networks of terrestrial rivers and they are associated with minerals that only form in the pr...

9. Missions to Mars  Read article

Human exploration of Mars started in the mid-1960s, in the first decades of the “space race.” While Russia concentrated its efforts on exploring Venus, the United States sent a series of spacecraft to our other neighbor, Mars. The pictures returned by the first few Mariner missions sh...

10. The Planets  Read article

The inner solar system has four terrestrial planets composed of rocky and metallic materials. Mercury is small and appears similar to the Earth's Moon. Its surface is heavily cratered, and its gravity is too weak to retain a substantial atmosphere. Venus is roughly Earth's size. Our "sister planet" ...