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September 29, 2015

Life on Mars? NASA discovers evidence of water


NASA has discovered evidence of water on the surface of Mars, raising the potential for life on the planet.

Since exploration of Mars started in the 1960s, scientists have looked for indications of life or conditions that may have once supported it.

Now, darkly shaded streaks appearing in satellite images taken of Mars’ surface appear to show seasonal flows of briny water on the slopes of craters and hillsides.

Evidence suggests that Mars once possessed a warm and wet climate, but became very dry and cold as it lost most of its atmosphere. The high salt content in the detected liquid explains why it has not frozen, according to NewsHour science correspondent Miles O’Brien.

“Flowing water has been kind of the Holy Grail on Mars,” O’Brien said. “Wherever we look on (Earth), where we see liquid water, we see life. It’s a prerequisite for life as we know it.”

A device called the HiRise instrument on the Mars Reconnaissance Orbiter currently circling the planet used spectral analysis to identify the content of the liquid after scientists first noticed the streaks in 2010.

Now, the questions for scientists include where the water originates from and whether it could support life despite its high salt content. Underground aquifers represent one possible source for the moisture, but the fact that it appears on top of slopes may also suggest some sort of humidity exists even in the dry Mars climate.

The discovery likely has NASA and other scientists eager to begin planning a mission to investigate the streaks more closely with the hope of answering the age-old question, “Are we alone in the universe?”

Warm up questions
  1. What do we know about the planet Mars?
  2. What is NASA?
  3. Why do scientists study outer space?
Critical thinking questions
  1. What is the significance of water on Mars?
  2. How is the water on Mars different than the water on Earth?
  3. Do you think NASA and other space agencies should try to send humans to Mars? Why or why not?
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