Month: October 2018

Thirty Years In The Life Of Supernova 1987A

Since it first appeared in the southern night sky on February 24th 1987, Supernova 1987A has been one of the most studied objects in the history of astronomy.

The supernova was the cataclysmic death of a blue supergiant star, some 168,000 light-years from Earth, in the Large Magellanic Cloud, a satellite galaxy of our own Milky Way Galaxy. It was the brightest supernova to appear in our skies since Kepler’s Supernova in 1604 and the first since the invention of the telescope.

The brilliant new star was first spotted by two astronomers working at the Las Campanas Observatory in northern Chile the night of the 24th: the University of Toronto’s Ian Shelton, and a telescope operator at the observatory, Oscar Duhalde.

Now, Yvette Cendes, a graduate student with the University of Toronto and the Leiden Observatory, has created a time-lapse showing the aftermath of the supernova over a 25-year period, from 1992 to 2017. The images show the shockwave expanding outward and slamming into debris that ringed the original star before its demise.

In an accompanying paper, published in the Astrophysical Journal on October 31st, Cendes and her colleagues add to the evidence that the expanding remnant is shaped — not like a ring like those of Saturn’s — but like a donut, a form known as a torus.

They also confirm that the shockwave has now picked up some one thousand kilometres per second in speed. The acceleration has occurred because the expanding torus has punched through the ring of debris.

Geological Survey Discovers Active Volcano 14,000 Feet Under The Sea

There are at least 20 to 40 volcanoes erupting on Earth at any given moment, but most of that volcanic activity is hidden from view at the bottom of the ocean. It is estimated that almost 5 cubic-miles of lava erupt every year along the mid-ocean ridges and submarine fault systems associated with subduction zones, where the oceanic crust is pulled into Earth’s mantle. This is twice the lava that erupts from all volcanoes found on land.

In 1973, the submarine Alvin by chance discovered “black smokers” on the seafloor near Hawaii. These underwater hot springs, named after the smoke-like 750 °F hot fluids that billow out from their vents, were the first evidence that there is geothermal activity to be found on the bottom of the ocean. In the last 500 years, only 17 deep submarine eruptions have been known, and even then mostly identified only by indirect evidence, like changes in the bathymetry of the seabed, plumes of volcanic ash and fluids dispersed in the water and by occasional pumice rafts appearing on the ocean surface.

Deep sea volcanoes are still poorly studied and most of what we know about submarine eruptions is based on studying outcrops, where the seabed was pushed by tectonic forces above the sea. When an eruption occurs under the water, water pressure prevents the explosions as seen on land. We do know that when lava erupts beneath the sea, it develops distinctive pillow structures. Cold water instantly chills the extruded lava, forming a thin crust that stretches to resemble a tube or pillows as new hot lava enters under it. As the pillow expands, its surface cracks, allowing some lava to flow out from it and form another pillow. Geologists would like to compare what they see in an outcrop with what actually happens during an eruption under water. Observing a submarine eruption is not easy. Rarely we know in time when an underwater volcano will erupt and expensive survey technology, like manned submarines or unmanned rovers, is needed to observe the eruption.

An international research team was quite lucky, as it apparently discovered traces of a very recent eruption of a still active submarine volcano. It is also the deepest volcanic eruption ever recorded. During a survey mission near the Mariana Trench in the Pacific Ocean, typical pillow structures were discovered at a depth of 14,000 feet. The submarine lava flow, as mapped following the pillow lava, is 650 to 2,600 ft wide, almost 450 ft thick and 4.5 miles long. Milky fluids rising from the ground indicated that the lava was still warm and therefore very young. A comparison with older surveys of the seafloor suggests that the eruption occurred sometime between 2013 and 2016.

Deep-sea volcanic eruptions differ in some important characteristics from volcanic eruptions in shallow waters. In 14,000 feet the water pressure is much higher as near the surface. Volcanic gases, important in pushing the lava out from the volcanic vents, can’t expand here as much as under normal conditions. The resulting eruption style is less violent. Also, rock fragmentation, caused by exploding bubbles in the lava, should be less effective, but the researchers found large quantities of broken rocks and ash. Apparently, the bottom water in 14,000 feet plays a major role in such a case. The cold (32-38°F) water coming into contact with hot lava flash-boils and expands enormously, and the force of the steam expansion deforms and fragments the lava. The researchers were also surprised how long the lava will stay warm despite the chilling temperatures. This observation may of interest for marine biologists, as such eruptions and their aftermath could provide a habitat for various lifeforms.

BREAKING NEWS: 6.8 Earthquake Hits North Tip of Cascadia Subduction Zone

Three powerful earthquakes struck off the coast of British Columbia Sunday night within an hour. This area sits at the northern end of the Cascadia Subduction Zone which is monitored closely due to its prediction of a cyclical mega-quake.

The United States Geological Survey reports a preliminary magnitude 6.6 earthquake struck near Port Hardy, Canada at 10:39 p.m. local time at a depth of about 7 miles (11 kilometers).

At 11:16 p.m., a magnitude 6.8 earthquake struck the same area at a depth of 13 miles (21 kilometers). At 11:22 p.m. a magnitude 6.5 earthquake struck the same area at a depth of 6 miles (10 kilometers). The U.S. National Tsunami Warning Center reported that a tsunami was not expected.

There was no initial word on damage or injury resulting from the quakes. The earthquakes centered about 355 miles northwest of Seattle. Several smaller quakes followed, including a 4.9-magnitude temblor at 11:36 p.m. PDT.

JUST IN: Cosmic Ray Particles That Tunnel Through Earth

A fountain of high-energy particles that resembles an upside-down cosmic-ray shower is detected for the second time by the Antarctic Impulsive Transient Antenna (ANITA).

ANITA detected an unexpected signal – radio waves coming from the ice with an inverted phase. The detection suggest the signals came from upward-moving particles that tunneled through Earth before erupting from the ice.

In a paper published in the journal American Geophysical Union (AGU) Space Weather, associate professor Nathan Schwadron of the UNH Institute for the Study of Earth, Oceans, and Space (EOS) and the department of physics says that due to this solar cycles vast drop in solar activity, a stream of cosmic ray particles are flooding Earth’s atmosphere – and further driving in and through Earth’s core.

In addition to a lower solar minimum cycle, Earth’s magnetic field continues to weaken which also allows a greater number of cosmic particles to enter our atmosphere. Some cosmic charged particles known as Ultra High Energy Cosmic Rays (UHECR) are millions of times greater in kinetic energy than cosmic rays. These powerful particles plow right through Earth’s upper and lower mantle, into the outer and inner core.

My research suggest the radiation of these particles has a significant influence on Earth’s core by increasing temperatures. As a natural result, Earth compensates to maintain its ambient temperature. This is done by sweating. Just as us humans sweat through our pores to manage an overheated body, the Earth sweats by releasing magma through its pores known as ‘mantle plumes’.

More Coming Later…

 

Orionids 2018 Meteor Shower Peaking Overnight Tonight

The Orionids meteor shower will peak overnight from Sunday, Oct. 21 to Monday, Oct. 22. The meteor shower, which will produce between 15 to 20 meteors per hour, is best seen between 2-5 a.m. The origin of the Orionids shower comes from Halley’s comet as it returns to our inner solar system.

Peaking during mid-October, the Orionids are considered one of the most beautiful showers of the year. Its meteors are fast, traveling at about 148,000 mph and leaving glowing “trains” – incandescent bits of debris in the wake of the meteor – which last for several seconds to minutes, according to NASA.

The shower’s radiant – or the point in the sky from which the Orionids appear to come from – is the constellation Orion but NASA said don’t limit your viewing to only that area. The Orionids should be visible throughout the night sky.

If you miss the Orionids, don’t fret. The Leonids meteor shower will peak on Nov. 17.

 

Antarctic Ice Shelf ‘Sings’ As Winds Whip Across Its Surface

Winds blowing across snow dunes on Antarctica’s Ross Ice Shelf cause the massive ice slab’s surface to vibrate, producing a near-constant set of seismic “tones” scientists could potentially use to monitor changes in the ice shelf from afar, according to new research.

The Ross Ice Shelf is Antarctica’s largest ice shelf, a Texas-sized plate of glacial ice fed from the icy continent’s interior that floats atop the Southern Ocean. The ice shelf buttresses adjacent ice sheets on Antarctica’s mainland, impeding ice flow from land into water, like a cork in a bottle.

When ice shelves collapse, ice can flow faster from land into the sea, which can raise sea levels. Ice shelves all over Antarctica have been thinning, and in some cases breaking up or retreating, due to rising ocean and air temperatures. Prior observations have shown that Antarctic ice shelves can collapse suddenly and without obvious warning signs, which happened when the Larsen B ice shelf on the Antarctic Peninsula abruptly collapsed in 2002.

To better understand the physical properties of the Ross Ice Shelf, researchers buried 34 extremely sensitive seismic sensors under its snowy surface. The sensors allowed the researchers to monitor the ice shelf’s vibrations and study its structure and movements for over two years, from late 2014 to early 2017.

Ice shelves are covered in thick blankets of snow, often several meters deep, that are topped with massive snow dunes, like sand dunes in a desert. This snow layer acts like a fur coat for the underlying ice, insulating the ice below from heating and even melting when temperatures rise.

When the researchers started analyzing seismic data on the Ross Ice Shelf, they noticed something odd: Its fur coat was almost constantly vibrating.

When they looked closer at the data, they discovered winds whipping across the massive snow dunes caused the ice sheet’s snow covering to rumble, like the pounding of a colossal drum (see: https://youtu.be/w56RxaX9THY).

They also noticed the pitch of this seismic hum changed when weather conditions altered the snow layer’s surface. They found the ice vibrated at different frequencies when strong storms rearranged the snow dunes or when the air temperatures at the surface went up or down, which changed how fast seismic waves traveled through the snow.

“It’s kind of like you’re blowing a flute, constantly, on the ice shelf,” said Julien Chaput, a geophysicist and mathematician at Colorado State University in Fort Collins and lead author of the new study published today in Geophysical Research Letters, a journal of the American Geophysical Union.

Just like musicians can change the pitch of a note on a flute by altering which holes air flows through or how fast it flows, weather conditions on the ice shelf can change the frequency of its vibration by altering its dune-like topography, according to Chaput.

“Either you change the velocity of the snow by heating or cooling it, or you change where you blow on the flute, by adding or destroying dunes,” he said. “And that’s essentially the two forcing effects we can observe.”

The hum is too low in frequency to be audible to human ears, but the new findings suggest scientists could use seismic stations to continuously monitor the conditions on ice shelves in near real-time. Studying the vibrations of an ice shelf’s insulating snow jacket could give scientists a sense of how it is responding to changing climate conditions, according to Douglas MacAyeal, a glaciologist at the University of Chicago who was not connected to the new study but wrote a commentary about the findings also published today in Geophysical Research Letters.

Changes to the ice shelf’s seismic hum could indicate whether melt ponds or cracks in the ice are forming that might indicate whether the ice shelf is susceptible to breaking up.

“The response of the ice shelf tells us that we can track extremely sensitive details about it,” Chaput said. “Basically, what we have on our hands is a tool to monitor the environment, really. And its impact on the ice shelf.”

Hurricane Michael: Death Toll Continues To Rise Amid Searches

Areas of the US devastated by Hurricane Michael last week are continuing to count the storm’s cost as the number of confirmed dead rises.

At least 27 deaths have been blamed on the hurricane across four US states – a number expected to increase further.

A volunteer organisation has said it is trying to find more than 1,100 people believed to be unaccounted for.

The storm destroyed buildings and flattened communities as it tore through the Florida panhandle region.

Most of the missing are said to be in Panama City and are elderly, disabled or live alone, co-founder of Houston-based CrowdSource Rescue Matthew Marchetti told the Reuters news agency.

That number has not been confirmed by regional officials, and the Florida Department of Health has created an online form for people to report friends and loved ones missing.

US President Donald Trump and First Lady Melania visited the storm-affected region in Florida and Georgia on Monday.

As of Wednesday morning, more than 150,000 homes and businesses were still reported to be without power.

There were also reports of armed looting of homes and businesses in some areas.

A major at Bay County’s Sheriff’s office, Jimmy Stanford, said that local police there had arrested about 10 suspected looters every night since Friday.