Gravitational waves: Monster black hole merger detected – BBC News
Image copyright IGO/Caltech/MIT/Sonoma State Image caption Artwork: The coalescing objects produced a single black hole over 80 times the mass of our star Gravitational waves have been picked up from the biggest black hole merger yet detected.
Scientists say their laser labs sensed the ripples in space-time emanating from this gargantuan collision on 29 July 2017.
The event saw two holes, weighing more than 50 and 34 times the mass of our Sun, uniting to produce a single object over 80 times the mass of our star.
It happened at least five billion light-years from Earth.
The discovery follows a major data re-analysis project .
Researchers from the LIGO-VIRGO Collaboration have also listed three other black hole mergers that were missed in the initial run-though of the data; and the promotion to full detection status of a previously uncertain “candidate”.
The re-analysis brings the total number of gravitational waves events now in the catalogue to 11. Ten are black hole mergers; one occurrence was the result of a collision between dense star remnants, so-called neutron stars.
Gravitational waves: So many new toys to unwrap Einstein’s waves detected in star smash Einstein’s waves win physics Nobel Image copyright Ligo Image caption The LIGO and VIRGO laser instruments are among the most sensitive scientific tools ever built Why have the detections come to light now? The international collaboration operates three laser interferometer facilities – in Washington and Louisiana states in the US, and Pisa province in Italy.
Their super-sensitive instruments “listened” for gravitational waves emanating from cosmic events during two periods, across 2015, 2016 and 2017.
Algorithms hunting through the colossal streams of data saw what they regarded as the obvious patterns relating gravitational waves at the time, but it was always planned to go back through the data and do a reassessment.
Writing on his blog at the weekend , collaboration member Prof Shane Larson from Northwestern University, in Evanston, said: “Since [the initial discoveries], we’ve been sifting through the data, looking at every feature, comparing it to our astrophysical predictions, cross-checking it against monitors that tell us the health of the instruments, determining if it appears in all the detectors, and using our most robust (but slow-running) super-computer analysis codes.”
It is this fine-tooth comb search that has thrown up the new black hole mergers. All of the new detections come from the second period of operation, which ran for nearly nine months from November 2016 to August 2017.
In the catalogue , they are given the “GW” prefix, for “Gravitational Waves”, followed by the date (yr/month/day) of occurrence: GW170729, GW170809, GW170818 and GW170823.
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Cannabis firm confirms investment talks with Marlboro maker – BBC News
Cannabis firm confirms investment talks with Marlboro maker 4 December 2018 These are external links and will open in a new window Close share panel Image copyright Getty Images Altria, the maker of Marlboro cigarettes, is in talks with a Canadian cannabis producer over a potential investment in the firm.
Canada’s Cronos Group confirmed the discussions but said it had not yet reached an agreement.
It follows reports that Altria was in talks to acquire Cronos as it moves to diversify from traditional smokers.
Canada legalised recreational cannabis in October – the second country in the world to do so.
Cronos confirmed in a statement “it is engaged in discussions concerning a potential investment by Altria Group Inc. in Cronos Group.”
“No agreement has been reached with respect to any such transaction and there can be no assurance such discussions will lead to an investment or other transaction involving the companies.”
‘Awe-inspiring’ cave discovered in Canada’s wilderness – BBC News
These are external links and will open in a new window Close share panel Image copyright Courtesy Catherine Hickson Image caption The entrance of ‘Sarlacc’s Pit’ A massive unexplored cave of “national significance” has been discovered in the Canadian wilderness.
It was spotted in April by a government survey team counting the caribou population in the remote Wells Gray Provincial Park, in British Columbia.
A group of cave specialists and geologists took a closer look at the discovery in September.
They said the cave “promises a dramatic new chapter in the story of Canadian cave exploration”.
Government biologist Bevan Ernst, who was on the caribou survey team, unofficially dubbed the discovery “Sarlacc’s Pit” because it looked to him a bit like the lair of a Sarlacc, a fictional creature from the planet Tatooine featured in Star Wars.
“We were looking for caribou, not caves,” Mr Ernst told the BBC.
He said helicopter pilot Ken Lancour was the one who thought the deep, snow-filled pit they had spotted was worth bringing to the attention of provincial parks officials.
Mr Ernst said the hard-to-access cave is in a region that “is about as remote as we get” and is near where the park’s mountainous landscape transitions into “glacier-type country”.
He suggested it might not have been previously spotted because it would usually have been covered with snow or avalanche debris when the team did their annual census.
Geologist Catherine Hickson and cave specialist John Pollack led the 9 September reconnaissance visit for a preliminary exploration of the cave after reviewing photographs and satellite images of the feature. Image copyright Courtesy Catherine Hickson Image caption Cave specialist Lee Hollis managed to descend partway into the cave
The entrance of the cave is 100m (328ft) long by 60m (197ft) wide – about the size of small football pitch or a National Football League football field.
The team believes that the cave is at least 180m deep, but were prevented from formally measuring the depth due to mist from a “turbulent” river that flows into the cave entrance.
Researchers say the dimensions are unprecedented in Canadian caving history.
Ms Hickson told the BBC that standing next to the cave’s massive entrance was “awe-inspiring”.
“You can see snow at the bottom but you can also see this black void,” she said.
The reconnaissance team believes the length of the cave runs at least 2km (1.25 miles).
Gravitational waves: Monster black hole merger detected – BBC News
End of Youtube post by SXS Collaboration
Gravitational waves – Ripples in the fabric of space-time Image copyright NSF Image caption The LIGO Louisiana lab has 4km-long pipes running out from its control centre Gravitational waves are a prediction of the Theory of General Relativity It took decades to develop the technology to directly detect them They are ripples in the fabric of space-time generated by violent events Accelerating masses will produce waves that propagate at the speed of light Detectable sources include merging black holes and neutron stars LIGO/VIRGO fire lasers into long, L-shaped tunnels; the waves disturb the light Detecting the waves opens up the Universe to completely new investigations What of the uncertain candidate?
The advanced laser labs in Washington and Louisiana began their first science run in September 2015 and almost immediately made the historic detection of a black hole merger on 14 September (GW150914) , a discovery that would later earn a Nobel Prize .
But less than a month later, the alarms triggered again at the lab to raise the possibility of a second detection. At the time, scientists didn’t think this event met the necessary criteria for a confident discovery, and so they labelled it LVT151012, where LVT stood for “LIGO-VIRGO Trigger”.
It was frequently mentioned in communications, but could not really be counted in the catalogue of full detections.
This has now changed following the re-analysis. The criteria are met and the LVT prefix is replaced with GW.
Prof Christopher Berry at Northwestern called GW151012 a “Cinderella story, a quiet signal that could”.
New warden wanted for Lihou Island – BBC News
New warden wanted for Lihou Island 4 December 2018 These are external links and will open in a new window Close share panel Image caption Lihou offers outdoor activities including climbing, abseiling, coasteering, rock jumping and archery A tiny island which comes with its own natural swimming pool needs a new warden.
The successful applicant will have Lihou – about 500m off the west coast of Guernsey – to themselves.
The job offers the chance to live off grid, surrounded by the Atlantic Ocean. with a tractor for a company car.
Duties include maintaining the island’s only house and looking after the nature reserve’s wildlife. Image copyright Guy Brown Image caption Lihou is owned by the States of Guernsey, but needs a warden to maintain and run the island’s only house
The new warden would need to have “fresh ideas” and be looking for new challenges, according to the incumbent, Richard Curtis. Image caption The house on Lihou has borehole providing water and solar panels for electricity
Lihou is only accessible by walking across a causeway at low tide, and can be cut off for days at a time.
The house was built in the 1960s but became derelict a few decades later, before being rebuilt and refurbished by the Lihou Charitable Trust in 2005. Image copyright Visit Guernsey Image caption On the western tip, a natural swimming pool – or “Venus Pool” – has formed in the coastline, with the sea topping it up on each passing tide
Mr Curtis, who is moving to France, said it had been “a privilege” to do the job for 14 years.
The island is under the administration of nearby Guernsey, although the new warden will be employed by the trust. Image caption Situated 500m from the west coast of Guernsey, the island has spectacular sunsets
The island has a rich history, with monks from Mont St Michel the earliest known settlers.
They built a monastery in the 12th Century – the remains of which can still be seen – as they tried to convert Guernsey’s pagan community.
Lihou was also used for target practice by occupying German soldiers during World War Two, with more than 100 pieces of ordinance found buried beneath the soil in the last few decades. Related Topics