Chapter 1, Section 2

Chapter 1, Section 2

The Universe

Scientists assume that the methods used to study Earth can be applied to other objects in the universe. To study the universe, chemists gather data from afar and analyze matter that is brought back to Earth.

In the early 1800s, scientists began to study the composition of stars by analyzing the light they transmitted to Earth. In 1868, Pierre Janssen discovered a gas on the sun’s surface that was not known on Earth. Norman Lockyer named the gas helium from the Greek word helios, meaning “sun.” In 1895, William Ramsay discovered helium on Earth.

Because the moon and the planets do not emit light, scientists must use other methods to gather data about these objects. They depend on matter brought back to Earth by astronauts or on probes that can analyze matter in space. Chemists have analyzed more than 850 pounds of moon rocks that were brought back to Earth. The large rock in Figure 1.14a is similar to rocks formed by volcanoes on Earth, suggesting that vast oceans of molten lava once covered the moon's surface. Figure 1.14b is a drawing of the robotic vehicle Opportunity. The vehicle was designed to determine the chemical composition of rocks and soil on Mars. Data collected at the vehicle’s landing site indicated that the site was once drenched with water.

Figures 1.14 With help from NASA, chemists study matter from other bodies in the solar system. (a) Apollo astronauts brought rocks from the moon back to Earth. (b) This artist’s drawing shows the robotic vehicle Opportunity on the surface of Mars.