Archive for the ‘Geology’ Category

This is real scientific breakthrough guys, scientists have used laser beams 60,000 billion times more powerful than a laser pointer to recreate scaled supernova explosions in the laboratory to investigate one of the most energetic events in the universe.

Supernova explosions, triggered when the fuel within a star reignites or its core collapses, launch shock waves that sweep through a few light years of space.

“It may sound surprising that a table-top laboratory experiment that fits inside an average room can be used to study astrophysical objects that are light years across,” said Professor Gianluca Gregori of Oxford’s Department of Physics.

“In reality, the laws of physics are the same everywhere, and physical processes can be scaled from one to the other in the same way that waves in a bucket are comparable to waves in the ocean. So our experiments can complement observations of events such as the Cassiopeia A supernova explosion,” said Gregori, who led the study.

The Cassiopeia A supernova explosion was first spotted about 300 years ago in the Cassiopeia constellation 11,000 light years away, its light having taken that long to reach us.

The optical images of the explosion show irregular ‘knotty’ features and associated with these are intense radio and X-ray emissions.

Whilst no one is sure what creates these phenomena one possibility is that the blast passes through a region of space that is filled with dense clumps or clouds of gas.

“Our team began by focusing three laser beams onto a carbon rod target, not much thicker than a strand of hair, in a low density gas-filled chamber,” said Jena Meinecke, an Oxford graduate student who headed the experiment.

The heat generated was more than a few million degrees Celsius and caused the rod to explode. The dense gas clumps that surround an exploding star were simulated by introducing a plastic grid to disturb the shock front.

“The experiment demonstrated that as the blast of the explosion passes through the grid it becomes irregular and turbulent just like the images from Cassiopeia,” said Gregori.

The research was published in the journal Nature Physics.


The sun, a star at the centre of the solar system, is known to provide ideal conditions for life to thrive on Earth. But, astronomers have claimed that it also leaves the planet wide open to harmful cosmic rays.

A joint team from University of Arizona and University of Texas in the US has found that the sun periodically leaves Earth open to assaults from interstellar nasties in a way that most stars do not, the ‘New Scientist’ reported.

The sun protects humans from cosmic rays and dust from beyond the solar system by enveloping in the heliosphere — a bubble of solar wind that extends past Pluto. These rays would damage the ozone layer and interstellar dust can dim sunlight and trigger an ice age.

However, when the solar system passes through very dense gas and dust clouds, the heliosphere can shrink until its edge is inside Earth’s orbit. So, in their research, the team, led by David Smith, has calculated the squeezing of various stars’ protective “astrospheres”.

Geology is special interest for me. Let me share something about the age of Himalayas – according to a new study, its about 15 million years old.

Read here….

The Himalayas may be a good five million years older than earlier estimates about the formation of the world’s highest mountain range, according to a joint study by Indian and British ocean scientists.

The new findings position the era of formation of the Himalayas to around 13.9-14.4 million years ago as against the earlier theory of eight million years.

The joint study carried out by Dr K S Krishna of National Institute of Oceanography (NIO) and his British colleagues, Southampton University Professor Jon Bull and Edinburg University Professor Roger Scrutton was published in the March issue of the Geological Society of America journal, Geology.

The study found that the Earth’s strong outer shell – the lithosphere – within the central Indian Ocean began to deform and fracture 13.9-14.4 million years ago, much earlier than previously thought.

It focuses on the tectonics-related deformation of the lithosphere below the central Indian Ocean.

India and Asia collided around 50 million years ago as a result of plate tectonics, large-scale movements of the lithosphere, which continues to this day, the study states.

This will impact our understanding of the birth of the Himalayas and the strengthening of the Indian-Asian monsoon, it adds.

“Compression of the lithosphere has caused large-scale buckling and cracking. The ocean floor has been systematically transformed into folds 100-300 kilometres long and 2,000-3,000 metres high, and there are also regularly spaced faults or cracks that are evident from seismic surveys and ocean drilling,” Krishna said.

The study paper mentions that the onset of this deformation marks the start of a major geological uplift of the Himalayas and the Tibetan Plateau, some 4,000 km further to the north, due to stresses within the wider India-Asia area.

Previous studies indicate that the uplift began around 8.0-7.5 million years ago, while others have said it started before 8.0 million years ago and perhaps much earlier, the study contends.

The researchers asanalysed seismic profiles of 293 faults (vertical cracks in the ocean floor) in the accumulated sediments of the Bengal Fan, a delta-shaped accumulation of land-derived sediments covering the floor of Bay of Bengal.

They demonstrate that deformation of lithosphere within the central Indian Ocean started around 13.9-14.4 million years ago. This implies considerable Himalayan uplift before 8.0 million years ago, which is when many geologists believe that the strong seasonal winds of India-Asia monsoon first started,” the study states.