NASA, the U.S. space agency, believes there's a good chance that we're not alone

NASA, the U.S. space agency, believes there's a good chance that we're not alone in the universe. Last fall, NASA began a new project called the High Resolution Microwave Survey (HRMS). Its aim: to find evidence of life in one of the billions of galaxies in the universe.

The search for intelligent life on other planets isn't new. It began almost 100 years ago. That's when scientists built a huge transmitter to send radio waves into space. Scientists thought smart beings on other planets might pick up the signals.

Scientists also have sent a message about humans and our solar system to a nearby constellation (星座 ). But because the constellation is 25,000 light years away, a return message wouldn't reach Earth for 50,000 years! So don't wait up for an answer.

So far, no extraterrestrial (地球外的 ) beings that we know of have returned our “ calls. ” But according to Dr. Jill Tarter, an HRMS scientist, we haven't exactly had our ears wide open. “ Now, however, ” says Dr. Tarter, “ we've built the tools we need to listen well.”

Last October, Dr. Tarter switched on the largest radio receiver in the world. It's an enormous metal bowl stretching 1,000 feet across a valley in Puerto Rico.

Meanwhile, another NASA scientist turned on a huge radio receiver in California's Mojave Desert. NASA hopes these big dishes-and others around the world-will pick up radio signals from new world.

Dr. Frank Drake has been searching for life in outer space for years. He explains the HRMS project this way: To listen to your radio, you move the tuner on the dial until the channels come in loud and clear: Now imagine radio receivers that scan our galaxy “listening” to 14 million channels every second. That's what NASA's radio receivers in Puerto Rico and California are doing.

But that's not all. Powerful computers hooked to the receivers examine every signal carefully. The computers try to match the signals to ones that scientists already recognize, such as human-made signals. If they can't, Drake and Tarter check on them. “It could prove there is radio technology elsewhere in the universe, ” says Dr. Tarter. “ And that would mean we're not alone. ” 26、NASA scientists started a new project in order to _______.

A、discover life in other galaxies

B、send human beings into space

C、find evidence of a new galaxy

D、confirm the number of galaxies

27、According to Dr.Jill Tarter ,the reason why we haven't received any return any return messages from outer space is that_______.

A、our ears are not sharp enough to hear them

B、our equipment hasn't been good enough

C、it takes millions of yuars for them to reach us

D、it takes quite a long time to send them

28、Dr.Jill Tarter compares the large receiver to _______.

A、the human ear

B、the universe