Borromeo Li Ka-kit, 17 Shun Lee Catholic Secondary School Evidence of water on Mars. People used to think that Earth was the only planet in our universe on which life could exist. But images taken by Nasa's Mars Global Surveyor in June 2000 using the Infrared Space Observatory's spectrometers raised the prospect that indigenous life could exist on Mars. Some experts believe the source could be underground 'pools' of water. This discovery is likely to spur future missions and boost hopes for life on Mars. Marvin Chung Man-ting, 15 Wah Yan College, Hong Kong The discovery of water on Mars. Some people have always thought that there could be aliens on Mars. However, there was no proof. Their excitement has been rekindled after ice was found on the surface of Mars. Water is vital for the survival of organisms. The discovery of ice on Mars increases the possibility of the existence of organisms on the Red Planet. Gullies and reservoirs of underground water were found as well. Our dream to live on Mars could come true. Perhaps one day we will meet each other somewhere on Mars, with a new outfit and a new house. Wu Ping, 15 STFA Tam Pak Yu College There are actually a lot more planets and stars in space. Besides the Milky Way Galaxy in which we live, there is the Triangulum Galaxy and the Andromeda Galaxy. Every time a new planet or a star is discovered, we learn a little bit more about space. Although Earth is just a small, blue planet, we can still discover things that are far away and we should be proud of that. Also, we should realise how insignificant we are. Discovering more about space is fantastic. It's like solving a mystery. Amy Siu Choi-hang, 17 SKH All Saints Middle School The moon lights up the night sky and people have expectations of that celestial body. The lunar terrain is made up of a bleak desert and inexhaustible outer-space dust. But the most interesting discovery is that the moon is hollow. In addition, when a solid object suffers a hit, it may cause two kinds of waves - longitudinal and surface. But a hollow object can only measure the surface wave. The exciting thing is after the astronauts landed on the moon and put the instrument on the lunar surface, they found out that it did not record the longitudinal wave, only the surface wave. Scientists were extremely surprised to discover that the moon is hollow. GET INVOLVED We'll kick one teen out each week until we have a winner. Who do you want out? E-mail firstname.lastname@example.org with the name of that person in the subject field. Only one vote per person. Votes must be cast by Wednesday 2pm. The ultimate winner will get a Nokia 5200 mobile phone worth HK$1,898.