Connect with us

Scientists find supernovae showered Earth with radioactive debris

Gorkha Post

Published

on

An international team of scientists has discovered evidence of a series of massive supernova explosions near our solar system, which showered the Earth with radioactive debris.

The scientists found radioactive iron-60 in sediment and crust samples taken from the Pacific, Atlantic and Indian Oceans.

The iron-60 was concentrated in a period between 3.2 and 1.7 million years ago, which is relatively recent in astronomical terms, said research leader Dr Anton Wallner from The Australian National University (ANU).

“We were very surprised that there was debris clearly spread across 1.5 million years,” said Dr Wallner, a nuclear physicist in the ANU Research School of Physics and Engineering. “It suggests there were a series of supernovae, one after another.

The team from Australia, the University of Vienna in Austria, Hebrew University in Israel, Shimizu Corporation and University of Tokyo, Nihon University and University of Tsukuba in Japan, Senckenberg Collections of Natural History Dresden and Helmholtz-Zentrum Dresden-Rossendorf (HZDR) in Germany, also found evidence of iron-60 from an older supernova around eight million years ago, coinciding with global faunal changes in the late Miocene.

A supernova is a massive explosion of a star as it runs out of fuel and collapses.

The scientists believe the supernovae in this case were less than 300 light years away, close enough to be visible during the day and comparable to the brightness of the Moon.

Although Earth would have been exposed to an increased cosmic ray bombardment, the radiation would have been too weak to cause direct biological damage or trigger mass extinctions.

The supernova explosions create many heavy elements and radioactive isotopes which are strewn into the cosmic neighbourhood.

Continue Reading

World

Magnitude 8.2 quake rattles Fiji

Thompson Reuters

Published

on

A massive quake of magnitude 8.2 struck in the Pacific Ocean close to Fiji and Tonga on Sunday but it was so deep that it was not expected to cause any damage, the US Geological Survey (USGS) said.

The US Tsunami Warning Center also said the quake was too deep to cause a tsunami.

The quake was 347.7 miles (560 km) below the Earth which would have dampened the shaking at the surface.

“I would not expect any damage. People will feel it but it’s so deep that I would not expect any damage,” USGS geophysicist Jana Pursley said by telephone.

The quake was initially reported as a magnitude 8.0 and then upgraded to 8.2, a magnitude that could cause tremendous damage had it not been so deep.

The epicenter was located 167 miles (270 km) east of Levuka in Fiji and 275 miles (443 km) west of Neiafu in Tonga.

The area is located on the earthquake-prone Ring of Fire.

Continue Reading

TOP PICKS