Australian scientists said that they have discovered why human beings have not been able to find out signs of alien life. It is quite sad a reason for the ones who wish to meet up with a real-life ET someday.

The paper was published in the journal Astrobiology, this week. The researchers theorized that that alien life forms cold have arisen a number of times in numerous places, but were rapidly snuffed out when acute heating or cooling left their host planets unfit to live in.

In a written statement, lead author of the study Aditya Chopra, an astrobiologist at Australian National University in Canberra, said that early life is fragile, thus it hardly evolves sufficiently fast to survive. In other words, it surrenders to extreme temperatures quite before it has a chance of evolution beyond the microbe level.

Everybody isn’t convinced with the same. While speaking to The Huffington Post in an email, Seth Shostak, senior astronomer at the SETI Institute in Mountain View, California, said, “Early Armageddon, as proposed here, may occur on some planets some of the time. However, while change may thin the cosmic herd, I can hardly imagine it inevitably wipes the herd out”.

Shostak cited Earth as a clear example of how life can evolve and continue for billions of years. Shostak said that in 65 million years, mammals transformed from being tiny rodents to us. It can be said that even if the neighborhood deteriorates, life has time sufficient time for adaption.

However, the fates of our planet’s own planetary neighbors are apparently consistent with the hypothesis.

In an email, an associate professor of astronomy at Australian National University and co-author of the paper, Charles Lineweaver told HuffPost Science that life on our planet is ‘an uncommon exception to the cosmic default, which is early extinction’