Essay title: Mars
Throughout the research all these years, humanity has rightly regarded Mars as the extraterrestrial planet, which is most likely to have life. Of the SunЎЇs nine planets, Earth and Mars are the only two that have been washed by water and possess atmospheres that are supportive to exist life. Mars has a rotation period, which is almost same to EarthЎЇs: the Martian day equals 24.5 hours. And Mars also has variations on seasons and amounts of sunshine that are similar to Earth.
However, Mars has thinner atmosphere than Earth, and also it cannot have liquid water on the surface. The planetЎЇs size and distances from the Sun explain most of the differences between Earth and Mars. Mars only has 54% of EarthЎЇs diameter and just 11% of EarthЎЇs mass. As a result of low mass, Mars has only 40% of EarthЎЇs gravitational force on objects at its surface. Mars is 130-160 million miles from the sun, while the Earth remains between 91-94 miles. The combination of its low mass and low solar heating leaves Mars with an uphill fight to maintain the conditions that favor life.
On August 7, 1996, President Bill Clinton, standing outside the White House in Washington, D.C, announced that a meteorite found evidence suggesting the existence of ancient life on Mars. Donald Goldsmith (1998) recorded the details in his book, saying Ў° The meteorite has in fact come from MarsЎEven more surprising, age-dating techniques based on the decay of radioactive elements had set its age at four and half billion years, making this Martian meteorite older than any other rock ever found on Earth or the moonЎancient four-pound visitor from Mars contained several types of evidence implying that incredibly tiny, long-dead forms of life had once inhabited crevices in the rock.Ў±. What did the scientists find in the rock of Mars? Science Magazine on August 16, 1996 published an article under that headings: The rock contains globules of carbonates, mineral deposits made from carbon and oxygen atoms combined with atoms such as calcium, iron, or magnesium. About 1% of the rockЎЇs mass consists of these globules, each of them not much more than a hairbreadth wide.
Malcolm Walters (1999) insisted Ў°The best candidates in a reconnaissance for Martian life are ancient lake bedsЎ±, Christopher McKay notes, an expert on Mars who worked at NASA (National Aeronautics and space Administration) in California, Ў°Think of the Bonneville Salt Flats in Utah, which are also an old lake bed. You drive a rover around the ancient lake, and then right up the bed of the bed of the creek that once fed it. ThatЎЇs where you drill to look for life.Ў± Christopher McKay feels confident that a better exploration of Mars will reveal clear signs of ancient life.
We know during long-vanished eras, three to four billion years ago or more, the environment on Mars was more favorable to life than it is now. Mars apparently had streams, lakes, rainfall and evaporation. But now Goldsmith (1998) insists