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Indian origin scientist tells why aliens can’t contact us

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Sydney: If the search for an alien life has not yielded any conclusive results in the last 50 years, it is probably because life on other planets was brief and has gone extinct soon after its origin owing to runaway heating or cooling on their planets, say astrobiologists led by an Indian origin scientist.

“The universe is probably filled with habitable planets, so many scientists think it should be teeming with aliens,” said Aditya Chopra from Australian National University (ANU).

“Early life is fragile so we believe it rarely evolves quickly enough to survive,” he added in a paper published in the journal Astrobiology.

“Most early planetary environments are unstable. To produce a habitable planet, life forms need to regulate greenhouse gases such as water and carbon dioxide to keep surface temperatures stable,” Dr Chopra added.

About four billion years ago the Earth, Venus and Mars may have all been habitable. However, a billion years or so after formation, Venus turned into a hothouse and Mars froze into an icebox.

“Early microbial life on Venus and Mars, if there was any, failed to stabilise the rapidly changing environment,” said co-author associate professor Charley Lineweaver.

“Life on Earth probably played a leading role in stabilising the planet’s climate,” he noted.

According to Dr Chopra, their theory has solved a puzzle.

“The mystery of why we haven’t yet found signs of aliens may have less to do with the likelihood of the origin of life or intelligence and have more to do with the rarity of the rapid emergence of biological regulation of feedback cycles on planetary surfaces,” he explained.

Wet and rocky planets, with the ingredients and energy sources required for life seem to, be ubiquitous. However, as physicist Enrico Fermi pointed out in 1950, no signs of surviving extra-terrestrial life have been found.

A solution to Fermi’s paradox, say the researchers, is near universal early extinction which they have named the “Gaian Bottleneck”.

“One intriguing prediction of the ‘Gaian Bottleneck’ model is that the vast majority of fossils in the universe will be from extinct microbial life, not from multicellular species such as dinosaurs or humanoids that take billions of years to evolve,” Lineweaver pointed out.(IANS)(image-wired.com)

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NASA’s Kepler Discovers Nearly 100 New Exoplanets

NASA researchers found that some of the signals were caused by multiple star systems or noise from the spacecraft

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UFO religion as a concept is now becoming a part of popular understanding.
Countless galaxies exist in the universe, each hiding secrets that humankind is yet to unearth. Pixabay
  • NASA’s Kepler has discovered nearly 100 new exoplanets
  • Some of the planets discovered are as large as Jupiter
  • NASA has also found planet which orbits very bright stars

An international team of scientists have confirmed the discovery of nearly 100 new exoplanets — planets located outside our solar system.

The discovery was based on data from the second mission of NASA’s Kepler Space Telescope or K2 released in 2014.

NASA has discovered nearly 100 exoplanets. Wikimedia Commons
NASA has discovered nearly 100 exoplanets. Wikimedia Commons

K2 searches for exoplanet transits by registering dips in light caused by the shadow of an exoplanet as it crosses in front of its host star.

NASA researchers found that some of the signals were caused by multiple star systems or noise from the spacecraft.

But they also detected planets that range from sub-Earth-sized to the size of Jupiter and larger.

Also Read: Milky Way’s neighbouring galaxy is of the same size, not bigger

One of the planets detected was orbiting a very bright star.

“We validated a planet on a 10-day orbit around a star called HD 212657, which is now the brightest star found by K2 missions to host a validated planet,” said lead author Andrew Mayo, a doctoral student at the National Space Institute (DTU Space) at the Technical University of Denmark.

Some of the planets found are as big as Jupiter. VOA
Some of the planets found are as big as Jupiter. VOA

For the study, appearing in the Astronomical Journal, the team started out analyzing 275 candidates of which 149 were validated as real exoplanets.

In turn 95 of these planets have proved to be new discoveries, Mayo said.

The Kepler spacecraft was first launched in 2009 to hunt for exoplanets in a single patch of sky, but in 2013 a mechanical failure crippled the telescope.

NASA has found many planets before as well. Wikimedia Commons
NASA has found many planets before as well. Wikimedia Commons

However, astronomers and engineers devised a way to repurpose and save the space telescope by changing its field of view periodically. This solution paved the way for the follow up K2 mission.

Adding the newly discovered exoplanets brings the total number of exoplanets by K2 mission to almost 300, the study said.

Also Read: NASA sounding rocket probing dark regions of space falter

The first planet orbiting a star similar to our own Sun was detected only in 1995. Today some 3,600 exoplanets have been found, ranging from rocky Earth-sized planets to large gas giants like Jupiter. IANS