Twenty-eight years ago today, on July 8th, 1997 (June 4th, 1997 in the lunar calendar), scientists discovered new evidence of life on Mars. The latest photos sent back by the American "Mars Pathfinder" spacecraft show that there was a catastrophic flood billions of years ago in the Ares Plain of Mars where the spacecraft landed. From these photos, you can clearly see the clear water marks left on the pebbles and rocks accumulated by the strong torrent. When the flood happened remains to be further analyzed. According to Michael Marin, a scientist involved in the research project of Mars Pathfinder, the time of the flood may have occurred 3 billion to 1 billion years ago. The photos sent back by Mars Pathfinder this time are the strongest evidence that there has been a flood on Mars so far. Marin said that the flooded area is equivalent to the area of the Mediterranean Sea, with a width of hundreds of kilometers and a flood flow of up to 1 million cubic meters per second. The water marks on the rocks are caused by salt and sediment in the torrent. The significance of the new discovery of "Mars Pathfinder" is that if liquid water once existed on Mars, it means that there may have been life on Mars. However, the current humidity on the surface of Mars is very low, with the highest temperature of minus 12 degrees Celsius during the day and minus 76 degrees Celsius at night. To this end, Matthew Grombeck, another scientist involved in the research of the project, pointed out that the new discovery of Mars Pathfinder raised such a question: Was Mars warmer and wetter in ancient times? Some scientists also say that the existence of torrents alone can't mean that there was life on Mars. The key is to find evidence that still water once existed on Mars. NASA scientists expressed confidence in finding such evidence. Within a few weeks this year, they will further analyze the photos about the flood of Mars sent back by Mars Pathfinder. Scientists believe that whether life ever existed on Mars is a big question. Only studying the surface landscape of Mars can't answer this question. Instead, it is necessary to collect Martian rock specimens and analyze them in laboratories on Earth. This work can't be carried out until 2005.