UFO is short for Unidentified Flying Object. It’s also called Flying Saucer. It is one of the most popular topics in the 20^thcentury. With films likeClose Encounters of the Third Kind andETin the 1970s came a rapid increase in reports of flying saucers and men from Mars. More than 20 countries said their people once saw the UFO and there were over 1,200 reports about the UFO. Some even said they saw aliens.

In July, 1916, Gaynor was a nine-year-old girl and lived in North Wales. One day, on her way home from school, she saw a silver object in a field not far from her home. The object looked like a saucer. Gaynor was very scared. She stayed in the tall grass and watched the door of the strange object open. She saw two aliens wearing silver suits get ou. Then they use something to examine the ground. They were short and had pink eyes. After about half an hour, the two aliens went back into the object. Then it took off. When Gaynor got home, she told her mother about her unusual experience, but her family decided to keep quiet about it. They didn’t want others to laugh at their daughter. However, 18 months later, Gaynor told her story to UFO scientists. They found out that Gaynor told the truth.

【推荐2】Our fascination with Mars has never stopped. However, in the early days of space exploration, visits were restricted to “fly-bys”, such as those by Mariner Space Probes, by means of which craft would simply pass the planet, taking pictures and collecting data as they went. The Viking “orbiters” were next, and later craft in the Viking series, known as “Landers”, began to study the surface, equipped with instruments which continued to collect data about the environment until they stopped working.

The more recent “Rovers” move around the planet’s surface as they gather information. Current proposals include missions to study geographic features, climate, and soil components, in order to determine, among other things, whether the planet can ever have supported carbon-based life forms. Scientists now believe that at some stage the planet cooled dramatically, resulting in the near-loss of its atmosphere and, thanks to the wearing away of some surface features mineral deposits and other factors, it is also believed that liquid water once flowed here.

One of the most famous craft is “Phoenix”, which landed in November 2008. Its mission was to obtain samples from beneath the surface by digging into the arctic ice while its camera provided geological data and other equipment scanned the atmosphere, measuring temperature and pressure in an attempt to discover whether the chemicals necessary for life might exist beneath the surface. The craft was expected to send back data for three months, but managed to hold out for further two. An especially important part of the project was the need to keep absolute cleanliness of the equipment in order to ensure that any organic material collected was not contaminated by microbes(微生物).

In the future manned landings may probably come true-and though it may seem an extremely difficult undertaking, plans have already been discussed for the “terraforming(行星地球化)”of the planet, giving it an atmosphere, oceans and other elements similar to earth, with, the possibility of human settlement.