Rare luminous nebula spotted 10 billion light years away poses cosmic puzzle

In a study conducted in 117 countries, researchers have found that the world is experiencing the most dramatic reduction in the seismic noise (the hum of vibrations in the planet's crust) in recorded history due to global COVID-19 lockdowns.

Measured by instruments called seismometers, seismic noise is caused by vibrations within the Earth, which travel like waves and the waves can be triggered by earthquakes, volcanoes, and bombs - but also by daily human activity like travel and industry.

This quiet period was likely caused by the total global effect of social distancing measures, closure of services and industry, and drops in tourism and travel, the study published in the journal Science, reported.

The new research, led by the Royal Observatory of Belgium and five other institutions around the world including Imperial College London (ICL), showed that the dampening of 'seismic noise' caused by humans was more pronounced in more densely populated areas.

"Our study uniquely highlights just how much human activities impact the solid Earth, and could let us see more clearly than ever what differentiates human and natural noise," said study co-author Stephen Hicks from ICL in the UK.

For the findings, the research team looked at seismic data from a global network of 268 seismic stations in 117 countries and found significant noise reductions compared to before any lockdown at 185 of those stations.

Researchers tracked the 'wave' of quietening between March and May as worldwide lockdown measures took hold.

The largest drops in vibrations were seen in the most densely populated areas, like Singapore and New York City, but drops were also seen in remote areas like Germany's the Black Forest and Rundu in Namibia.

Citizen-owned seismometers, which tend to measure more localised noise, noted large drops around universities and schools around Cornwall, UK and Boston, US - a drop in noise 20 per cent larger than seen during school holidays.

The findings showed that countries like Barbados, where lockdown coincided with the tourist season, saw a 50 per cent decrease in noise.

"The changes have also given us the opportunity to listen in to the Earth's natural vibrations without the distortions of human input," the study authors wrote.

Earlier in April, a study published in the journal Nature, reported at least a 30 per cent reduction in that amount of ambient human noise since lockdown began in Belgium.

Chennai, Jun 22: Commuting the death sentence to life imprisonment for five convicts, the Madras High Court on Monday set free Chinnasamy, the main convict, who had also been sentenced to death in the Udumalpet Shankar honour killing case.

A Division Bench comprising Justice M. Sathyanarayanan and Justice M. Nirmal Kumar also dismissed the appeal by the state police against the acquittal of three persons by a lower court.

The Bench ordered the five convicts sentenced for life to undergo a jail term of not less than 25 years.

In 2016, V. Shankar, who had married C. Kausalya, was killed by a gang in Udumalpet in Tamil Nadu. The gang also injured Kausalya in the attack.

It was alleged the parents of Kausalya -- Chinnasamy, Annalakshmi -- were against the marriage.

P. Pandidurai, the uncle of Kausalya at the behest of Chinnasamy and Annalakshmi had hired a gang to kill Shankar.

The gang killed Shankar in broad daylight in a public place and Kausalya too got injured in the attack as she tried to save her husband.

The Principal District and Sessions Court in Tiruppur had convicted and sentenced to death six accused persons -- Chinnasamy, P. Jagadeesan, P. Selvakumar, M. Manikandan, M. Mathan alias Michael and P. Kalaithamilvaanan.

The court also sentenced two other accused, K. Dhanraj for life and Manikandan to a five year jail term, while acquitting Annalakshmi, Pandidurai and Prasanna.

The convicts had filed an appeal against their sentence in the Madras High Court while the police filed an appeal against the acquittal of three persons.