"Earth 2.0", "Earth twin" or "older brother"? Whatever you call Kepler-452b, the Earth-like star discovered by NASA has caught the attention of people around the world, with the Chinese certainly no exception.

Many in China stayed awake for the big news promised at midnight Beijing Time on Thursday.

Millions of them are excited by the administration's discovery of a planet that it says has a "substantial opportunity" to host life, but this has been tempered by the realization that they will not be able to visit Kepler-452b.

On China's Twitter-like microblogging service Sina Weibo, more than 44 million people have read posts with the hashtag #Another Earth#, and nearly 90,000 have taken part in the discussion.

The comment "Even Earth has found its other half, why am I still single?" became so popular that it's difficult to trace its original writer.

China Daily echoed this with a post saying "We wish you happiness with your other half, Earth!"

Cartoonist "Wangzuozhongyou", who has some 330,000 Sina Weibo followers, designed two pictures with the words "Earth" and "brother".

Someone with the screen name "Yeweiyang" suggested, "There will come a a day when human beings possess one passport for Earth, and we travel around the universe with Jupiter, Pluto as our destinations."

The books channel of Sina.com treated the occasion as an opportunity to promote several classic books about the universe, including Stephen Hawking's "The Universe in a Nutshell" and "A Brief History of Time", under the banner "Tips for moving from Earth to another planet".

Despite excitement among the media and the public, science organizations have kept a clear head.

Guokr.com, a Chinese science social networking service, published an article explaining what the discovery really means.

"If you take the media's enthusiastic tone too seriously, you would be disappointed by the NASA release," it said, throwing something of a wet blanket on Chinese euphoria.

Even if Kepler-452b is an Earth-like rocky planet as scientists have speculated, it wouldn't be suitable for human survival, Guokr said in a piece citing scientists from the Search for Extraterrestrial Intelligence (SETI) Institute.

It quoted Doug Caldwell, a SETI Institute scientist working on the Kepler mission, as saying, "Kepler 452b could be experiencing now what Earth will undergo more than a billion years from now, as the Sun ages and grows brighter."

Caldwell was also quoted as saying that "the increasing energy from its aging sun could be evaporating any oceans, leaving behind large lakes ringed with mineral deposits."

Guokr joked, "This is the big news you've been waiting for: Kepler-452b is about 1,400 light years from Earth, and has a better-than-average chance of having a rocky composition. That's all and nothing more."

Netizens expressed their disappointment. "I stayed up the whole night... for this?" said Weibo user "Yang Haosheng".

"It takes millions of years to get there. Let's just forget it and go to bed," suggested "Hanfei".

However, "Jizhezhanwang" said, "Kepler-452b may not be a second home for human beings, but [the planet's discovery] is part of our constant exploration of the universe, which demonstrates the charm of science."