|
| |
|
|
Dara radioed a log entry to Mission Control. Then she brought onscreen a file titled COLLECTING ENVIRONMENTAL SAMPLES. Although she had studied the file several times, she read it again. A gray, crater-covered globe loomed large in the window.
SAM's voice boomed through the control panel. "Activate all sensors, Humans. Final approach to Mercury has begun. Be aware of these facts. Mercury is small, with a diameter of about 3,030 mi (about 4,900 km). The planet is barren and rocky, with little or no atmosphere and no vegetation. Gravity is weak. A human weighing 100 Earth pounds will weigh only 38 pounds on Mercury. Distance from the Sun is 36,000,000 mi (57,900,000 km).
"The planet rotates slowly. Thus a Mercury day is long, about 59 Earth days. The planet moves swiftly around the Sun. One revolution, a Mercury year, is only 88 Earth days.
"With no atmosphere to even out temperatures, the planet is usually very hot or very cold. Surface temperatures may be 800 }S?&F (425x°C) during the day and -280S¨ }SF (-175eg;&dC) at night. Because of heat and radiation from the Sun, the landscape may be glazed with cinders.
"Landforms tell history. The planet is covered with deep craters created when large meteorites crashed into it billions of years ago. The largest crater is the Caloris Basin, a low-lying area about 800 mi (1,300 km) across and ringed with mountains. The planet also has scarps, ridges of cliffs that were probably pushed up when the planet shrank after its formation."
Brenn said, "Dara, let's review the facts about Mercury and decide how to handle each problem, one by one."
------------------------------------------------------------------------
QUESTIONS
Help Brenn and Dara make their list of Mercury facts. Answer the questions below.
1. What is the atmosphere like? _________________________________________
Will the twins be able to breathe without special equipment on Mercury?___________
2. Is there vegetation on Mercury? Will the twins be able to get any plant samples?______
3. What are temperatures like on the planet? _____________________ Compare these temperatures to some we know. What is room temperature on Earth? _______
How cold is a freezing winter day? ____________ How hot is the oven when we bake
potatoes or a cake?____________
4. How strong is the gravity on Mercury? __________________________________
Will the twins be able to jump high and far on Mercury? ______________________
5. What are the landforms like? What will the twins be walking, wading, or climbing across?
______________________________________________________________
Writing Assignment: On the back of this sheet, write a paragraph explaining all the preparations Brenn and Dara should make for their exploration of Mercury. What kind of shields will the ship need? What kind of suits and shoes would work best?