An artistic illustration compares Earth (L) to a planet beyond the solar system that is a close match to Earth, called Kepler-452b in this NASA image released on July 23, 2015. [Photo/Agencies]

In a rare negative response to a scientific discovery, the Chinese Internet fell into deep melancholy at NASA's announcement that it had found an Earth-like planet, Kepler-452b. What prompted the disappointment?

While exciting scientific discoveries might be met with bewildered indifference from Penny of the hugely popular TV series The Big Bang Theory, the Chinese response to NASA's announcement perhaps came from setting their expectations too high.

Conditions on the planet seem ideal enough: Kepler-452b is positioned about as far from its parent star as Earth is from the sun, completing an orbit in 385 days, compared to Earth's 365-day orbit. At that distance, surface temperatures would be suitable for liquid water, a condition believed to be critical for life, according to details revealed by the US space agency.

So, much of the disappointment comes from the fact that Kepler 452b is very far away – 14,000 light years away, to be precise, making interstellar migration virtually impossible, and squashing hopes of being able to start over with a pristine new Earth.

Chinese netizens were probably also disappointed because of the way the information was revealed. They experienced an emotional roller-coaster since media outlets hinted at a major finding on Thursday afternoon. Many people went to bed in hopes that when they woke up the next morning – NASA's announcement came late at night on Beijing time – they would receive life-changing, revolutionary news. Sci-fi aficionados speculated that perhaps extraterrestrials weren't just the stuff of Hollywood blockbusters, while fantasists dreamed of building a whole new world.

Tech website guokr.com summed up the disappointment with a sarcastic post on Sina Weibo, China's Twitter-like social networking service:

"This is the so-called big news announcement…there's a better than ever chance that the planet is rocky. That's it.".

However, other Weibo users criticized the post's ungrateful tone. "What do you mean ‘that's it'? Doesn't a scientific breakthrough deserve more than this?" read one comment.

Others questioned the wisdom of looking for another planet to colonize in the first place, seeing such hopes as irresponsible escapism. We should be concentrating on making Earth a better world first, they argue. "Even if the planet is within the reach of colonization, do you think we can do any good there with our current environment-damaging practices?" asked one netizen pointedly.

Scientists agree that so far, Earth seems pretty unique.

"There doesn't seem to be a replacement for Earth in the universe", said Zheng Yongchun, researcher of the National Astronomical Observatories with the Chinese Academy of Sciences.

The right combination of water, air, gravity, and magnetic fields are all necessary for a planet to nurture life, and it's difficult to find an alternative that has all these conditions tuned as perfectly as Earth, Zheng told Caijing magazine.

"After all, we are on a lonely planet," he said.

Seems like we better settle in for the long haul.