The planet Mars
A Why is Mars so exciting for scientists? Probably because it is the planet that is
the most similar to Earth. Most of the planets in our solar system, like Mercury,
Venus and Neptune, are hostile environments. They are extremely cold or
extremely hot, with poisonous gases and constant volcanic eruptions. In contrast,
Mars is a planet which, at some time in the past may have been, like Earth, home
to life. But for life to exist there, scientists agree that Mars must at one time have
had liquid water, not ice. The temperature on Mars today is too cold for liquid
water. However, there is clear evidence that ice exists, in the polar caps. The
question is, has Mars ever had running water?
B It is generally thought that it has. There is some evidence that there were once
rivers, lakes, and possibly oceans. However, the evidence is mostly indirect. Ice
has been found under the surface of the planet, for example. Scientists have
never found direct evidence, until now.
C A recent probe to Mars seems to have provided, if not proof, at least clear
evidence for free-flowing water. At a cost of two and half billion dollars,
Curiosity, a roving vehicle, was sent to Mars to find out if life could exist there.
And Curiosity has made an exciting discovery. It has sent back pictures of rocks
which have other small stones in them. The stones are smooth and are too big to
have been moved by the wind. The scientists studying the pictures believe that
the most likely reason that they are smooth and stuck in the rocks is that, at some
time in the past, there was running water. They believe that this water must have
been between 1/10th to 1/2 meter deep.
D At the time of writing, the roving vehicle is still on its mission to search for
signs of life on Mars. Scientists are undecided whether to examine the rocks
further right now. For example, they could find out the chemical structure by
carrying out a chemical analysis of the rocks. However, this analysis is time-
consuming and costly, and so they are unwilling to start on this process until
Curiosity has explored the planet more. The thinking is that perhaps even greater
evidence exists to support the theory that there was once running water on Mars,
The planet MarsA Why is Mars so exciting for scientists? Probably because it is the planet that is the most similar to Earth. Most of the planets in our solar system, like Mercury, Venus and Neptune, are hostile environments. They are extremely cold or extremely hot, with poisonous gases and constant volcanic eruptions. In contrast, Mars is a planet which, at some time in the past may have been, like Earth, home to life. But for life to exist there, scientists agree that Mars must at one time have had liquid water, not ice. The temperature on Mars today is too cold for liquid water. However, there is clear evidence that ice exists, in the polar caps. The question is, has Mars ever had running water? B It is generally thought that it has. There is some evidence that there were once rivers, lakes, and possibly oceans. However, the evidence is mostly indirect. Ice has been found under the surface of the planet, for example. Scientists have never found direct evidence, until now.C A recent probe to Mars seems to have provided, if not proof, at least clear evidence for free-flowing water. At a cost of two and half billion dollars, Curiosity, a roving vehicle, was sent to Mars to find out if life could exist there. And Curiosity has made an exciting discovery. It has sent back pictures of rocks which have other small stones in them. The stones are smooth and are too big to have been moved by the wind. The scientists studying the pictures believe that the most likely reason that they are smooth and stuck in the rocks is that, at some time in the past, there was running water. They believe that this water must have been between 1/10th to 1/2 meter deep.D At the time of writing, the roving vehicle is still on its mission to search for signs of life on Mars. Scientists are undecided whether to examine the rocks further right now. For example, they could find out the chemical structure by carrying out a chemical analysis of the rocks. However, this analysis is time-consuming and costly, and so they are unwilling to start on this process until Curiosity has explored the planet more. The thinking is that perhaps even greater evidence exists to support the theory that there was once running water on Mars,
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