5 . Is there anybody out there? For centuries humans have wondered although the ways in which we have gone about this have varied. As we have gained a greater understanding of the universe, our searches have taken on more concrete(具体的) forms. Questions about aliens(外星人) have become a subject for science rather than science fiction.

Now new cooperation between the Very Large Array (VLA) observatory in New Mexico and the SETI Institute in California means that our curiosity about whether aliens exist can be closer than ever before to being satisfied. Data from the VLA’S 28 radio telescopes, used to scan a vast area of sky, will be fed through a special supercomputer that will search for distant signals.

How likely it is that a signal will be found, and what this might mean, are hard questions to answer. SETI’s existing projects have not discovered any signals from other planets so far. But recent discoveries in space and Earth sciences have provided some encouragement for those who are enthusiastic about the possibility, however remote, of detecting other civilizations.

Once it was thought that our solar system could be unique. Since the discovery of the first exoplanet (a planet beyond the solar system) in the 1990s, thousands more have been located. Around one in five stars is now thought to have a planet in their orbit(运行轨道) in a so-called “habitable(适合居住的) zone”—that is, at a distance from the star where the temperature means that life is theoretically possible.

Are Earth’s 7.5 billion humans, along with billions of other animals and plants they share their home with, on their own in the universe? If there is another life form somewhere, could it be as intelligent as humans? Or could it threaten them? I think all of these need further exploration. As explorations of Mars continue, and a new set of observations from the James Webb Space Telescope are set to begin, our interest in the possibility of alien life appears as much as before.

6 . Despite what so many people would love to believe, NASA hasn’t discovered any evidence of past or present intelligent life on Mars. So, when the Curiosity rover (好奇号探测器) found something suspicious on the Red Planet’s surface, they were not only surprised but also a little bit worried.

The thin fragment was suspicious enough to guarantee its own name, with NASA’s Curiosity rover team calling it the “Pettegrove Point Foreign Object Debris,” named for the location where it was discovered. With no idea what it was or where it came from, the rover’s handlers began to worry that it might actually be a piece of the rover itself, suggesting some unseen damage or other issue with the robot. Thankfully, those concerns seem to have been unfounded.

In a new update from NASA the object has now been identified as a natural piece of rock rather than a piece of any man-made craft or vehicle. The team analyzed the bizarre object with a tool called the ChemCam RMI. The instrument uses a laser (激光器) to sniff out the makeup of anything it’s pointed at, and the results for this particular piece of debris revealed that it’s actually just a very thin piece of rock.

NASA describes the inspection: The planning day began with an interesting result from the previous plan’s ChemCam RMI analysis of a target that was referred to as “Pettegrove Point Foreign Object Debris” (PPFOD), and speculated to be a piece of spacecraft debris. In fact it was found to be a very thin flake of rock, so we can all rest easy tonight—Curiosity has not begun to shed its skin!

How this particularly thin sliver of rock got to where it is—and why it seems to be a different colour than the surrounding sand and debris —remains unexplained, but at least the rover isn’t falling apart.

7 . Do you think alien beings exist somewhere in the universe? It seems like Mars, our closest neighbor, has inspired the most science fiction as the place where aliens are most likely to come from. Recent Mars probes (探测) have shown us that there is no life on that planet—at least not now. But that does not mean that life does not exist elsewhere—after all, the universe is really big. A lot of scientific research is going on in the search for “extraterrestrial life”.

Think about it—why should the seven billion people on this little planet be the only living beings in the universe? It would, in fact, seem logical that this is not the case. So scientific research in this matter is based around the idea of finding other planets that have environments that can support life —environments similar to the Earth. The search is on for the evidence of the existence, or earlier existence of life: from very wise beings to simple organisms (有机物).

So far, there have been a number of theories as to which planetary bodies may have an atmosphere that can support such life and therefore deserve closer attention. As for places within our own Milky Way Galaxy, it has been assumed over the decades that Mars and Venus, as well as some of the moons of Jupiter and Saturn, may have been hosts for life. Now, as technologies have improved and we can obtain measurements of the composition of the atmosphere on extra-solar planets, the chances of finding “alien” life forms are increasing.

There has been a theory that some of the planets in the habitable zone of the red dwarf star Gliese 581 may be able to support life. In 2007, scientists discovered exoplanet Gliese 581c—and felt that its atmosphere was most suitable for supporting life. But further research revealed that it would not. Now, attention has been turned to Gliese 581d, at the outer edge of the star’s habitable zone. The main standards for deciding whether a planetary body can be life-supporting are atmospheric conditions which allow the existence of water. Gliese 581 is about 20. 4 light years away from the Earth, so even if life does exist there, the distance would mean that communication would be unlikely.

Having said this—who says alien life forms (if they exist) need water?