Space is the final frontier (前沿). Sending rockets into space has become almost common. The demand for communications satellites and space-based image services is growing.

Today, space efforts cost about $200 billion a year. Joint efforts between governments and businesses are helping to lower costs and increase our understanding of the universe.

The business of space looks good for Orbital ATK, a company based in the United States. In January, the company launched its Antares rocket. The rocket was carrying the first of eight planned supply shipments to the International Space Station. Orbital ATK is one of the two American companies paid by NASA to transport supplies to the space station.

A company called Arianespace is a private European space business. Clayton Nowry heads the American division of the company. He says the increase in rocket launches is partly the result of increased demand for space-based technologies. These include high-definition (高清的) broadcasts and satellite broadband services.

While there is more demand for satellites, the end of NASA's Space Shuttle program in 2011 has hurt the space industry. Janice Starzyk works at International Launch Services. She works on education issues at the Washington Space Business Roundtable. She said, "It's a pity that the program's shutdown was a huge, huge set of lay-offs (下岗人员) in the industry."

But even as NASA reduces its spending, other countries have announced plans to explore space. In December 2013, China became just the third country to land an unmanned space vehicle on the moon. A month later, India sent its first communications satellite.

Most people feel that dreams are unique to humans, but many dog owners will likely disagree. They have noticed that their dogs at various times during the sleep may shake legs, snort(哼)and sometimes growl (低声吼叫)which gives the impression that they are dreaming. These things may wonder us about whether dogs dream.

Scientists confirm that dogs probably do dream. It turns out that dog brains and human brains have many similarities during sleep cycles. Researchers used special machines to measure electrical activity in a dog’s brain and a human’s brain. Scientists already knew that when humans dream, a certain part of the brain is active during sleep. Researchers discovered that the same part of the brain is active in sleeping dogs. Scientists have other data that back up these findings.

Many people dream that they are trying to move but cannot. Interestingly, part of that experience is not a dream. When people sleep, the brain produces a chemical that causes the dreamer to become temporarily paralyzed(使麻痹). Researchers think this happens so that people cannot physically act out dreams while they are sleeping. Dog brains make the same chemical. In one study during which this chemical was blocked, sleeping test dogs performed physical activities, such as standing up, sniffing around the room for imaginary rabbits, or chasing (追逐)imaginary balls.

Because of these similarities, researchers believe that the content of a dogs dream might come from the same source as a human’s dream. “People’s dreams are usually based on things they did that day, ” says Dr. Samantha Hudspith. “So we have reasons to believe that dogs dream about the things theyve done that day. Of course, there will never be a way to prove this. Dogs cannot describe their dreams the way that humans can. ”