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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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New Study Shows That Binaries From Globular Clusters Can be Detected by LISA

The European Space Agency's next-generation Laser Interferometer Space Antenna (LISA) gravitational wave detector can potentially detect dozens of binary files in the globular clusters of the Milky Way, scientists say.

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In particular, these models suggest that the Kuiper Belt -- a cold region beyond the orbit of Neptune -- should contain a small fraction of rocky bodies from the inner solar system, such as carbon-rich asteroids, referred to as carbonaceous asteroids.
representational image, pixabay

The European Space Agency’s next-generation Laser Interferometer Space Antenna (LISA) gravitational wave detector can potentially detect dozens of binary files in the globular clusters of the Milky Way, scientists say.

Globular clusters are dense environments containing millions of tightly packed stars and are efficient factories for gravitational wave sources.

LISA, which is expected to be in space in 2034, will be able to detect binary sources — pairs of orbiting compact objects.

These binary sources will contain all combinations of black hole, neutron star and white dwarf components.

While 150 globular clusters have been observed so far in the Milky Way, one out of every three clusters will produce a LISA source.
Representational image. Pixabay

LISA will also be sensitive to gravitational waves of a lower frequency than those detected by the Earth-bound Laser Interferometer Gravitational-Wave Observatory (LIGO)

“LISA is sensitive to Milky Way systems and will expand the breadth of the gravitational wave spectrum, allowing us to explore different types of objects that aren’t observable with LIGO,” said lead author Kyle Kremer, a doctoral student at the Northwestern University in Illinois, US.

While 150 globular clusters have been observed so far in the Milky Way, one out of every three clusters will produce a LISA source.

Approximately eight black hole binaries will be detectable by LISA in our neighbouring galaxy of Andromeda and another 80 in nearby Virgo, the study showed.

The research, published by the journal Physical Review Letters, is the first to use realistic globular cluster models to make detailed predictions of LISA sources.

Also Read: NASA Is Sending a Helicopter to Mars in 2020 

The team used more than a hundred fully evolved globular cluster models with properties similar to those of the observed globular clusters in the Milky Way.

The models were run on Quest, Northwestern’s supercomputer cluster. This powerful resource can evolve the full 12 billion years of a globular cluster’s life in a matter of days. (IANS)

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