’Best ever’ simulation solves 40-year black hole mystery

’Best ever’ simulation solves 40-year black hole mystery
This handout photograph released by Northwestern University on June 5, 2019, shows a vertical slice of a black hole alignment as scientists on unveiled the most detailed simulation of a black hole yet seen, solving a mystery dating back more than four decades over how the star-devouring monsters consume matter. (AFP)
Updated 06 June 2019

’Best ever’ simulation solves 40-year black hole mystery

’Best ever’ simulation solves 40-year black hole mystery
  • It is precisely this electromagnetic effect that causes matter to fall to the center of the black hole

PARIS: Scientists on Thursday unveiled the most detailed simulation of a black hole yet, solving a mystery dating back more than four decades over how the star-devouring monsters consume matter.
Coming fresh on the heels of the first ever photo of one of the giant objects, which are scattered across the Universe, astrophysicists are now several steps closer to understanding how they form and develop.
A black hole is born when a large star collapses in on itself. Far from being a “hole,” they are instead incredibly dense objects with a gravitational pull so strong that nothing, not even light, may escape them.
As they suck in matter such as gas, dust and space debris, they form an accretion disk — a churning mass of super-accelerated particles that are among the brightest objects in the Universe — around them.
It is the accretion disk that can be seen as a blurry halo around the image of the black hole released in April from the Event Horizon Telescope.
But accretion disks are nearly always tilted at an angle to the orientation of the black hole, known as its equatorial plane.
In 1975, Nobel Prize-winning physicist John Bardeen and astrophysicist Jacobus Petterson theorized that a rotating black hole would cause the inner region of a tilted accretion disk to line up with the black hole’s equatorial plane.
But no model could ever work out how, precisely, that would happen. Until now.

A team of astrophysicists from Northwestern University, Oxford University, and the University of Amsterdam, used graphical processing units to crunch large sets of data and simulate how black holes interact with their accretion disks.
Crucially, their approach gave them the computing power to account for magnetic turbulence, which occurs when different particles churn at different speeds within the accretion disk.
It is precisely this electromagnetic effect that causes matter to fall to the center of the black hole.
Alexander Tchekhovskoy, assistant professor of physics and astronomy at Northwestern’s Weinberg College of Arts and Sciences, likened matter accumulating near a black hole to throwing a dart toward the board at random.
“If you don’t really aim it will never hit the bullseye,” he said. “In the same way, when (matter) falls into the black hole it has some rotation but this rotation will have nothing generally to do with how the black hole rotates. The two rotations will not know anything about each other.”

Previous simulations manually predicted the additional friction their creators believed was needed to make matter move toward the black hole.
“Whereas now in our model, we don’t have to postulate this friction,” Tchekhovskoy told AFP. “We put in magnetic fields and these actually cause an instability that then causes friction and the disk falls in as a result.”
This might seem like a small detail but it directly affects how fast black holes spin and, consequently, what effect they have on the galaxies that surround them.
The simulation, which produces a disk with two jets of gas and magnetic fields protruding from the center like fountains, shows the inner part of the accretion disk aligning perfectly with the black hole’s equator even as the outer part remains at an angle.
“Before now there was a worry that when you take into account all the complications that come with matter interacting with a black hole, such as magnetic fields, the turbulence in the disk, the swirling motions — those things might kill the alignment effect,” said Tchekhovskoy.
“We found that, no, it doesn’t kill it, actually the inner parts of the disk do align with the black hole and we can now more confidently make predictions about how black holes would look.”


Astronauts leave ISS, begin return journey to Earth on SpaceX craft

Astronauts leave ISS, begin return journey to Earth on SpaceX craft
Updated 02 May 2021

Astronauts leave ISS, begin return journey to Earth on SpaceX craft

Astronauts leave ISS, begin return journey to Earth on SpaceX craft
  • Astronauts Hopkins, Victor Glover, Shannon Walker and Japan’s Soichi Noguchi went to space last November as the crew on the first fully operational mission to the ISS aboard a vehicle made by Elon Musk’s SpaceX

WASHINGTON: Four astronauts left the International Space Station on Saturday aboard a SpaceX vessel, after more than 160 days in space which will culminate in a splash landing off the Florida coast.
The Crew Dragon capsule undocked from the ISS as scheduled at 8:35 p.m. (0035 Sunday GMT). With the flight back to Earth expected to take six-and-a-half hours, the crew was scheduled to splash down in the dark of night off Panama City, Florida, in the Gulf of Mexico at 2:57 am.
“Dragon separation visually confirmed,” a NASA commentator said after two sets of six hooks tying the capsule to the ISS retracted.
The capsule then fired a series of short bursts with its thrusters to gently ease away from the ISS.
NASA livestream footage showed the Crew Dragon capsule moving off into the dark as it began its journey back to Earth, its rear engines lighting up in small flashes.
Seven astronauts remained on the ISS including a new crew of four who arrived on a different SpaceX craft last week.
“Thanks for your hospitality,” Michael Hopkins, one of the departing US astronauts, said as the capsule moved away. “We’ll see you back on Earth.”
NASA and SpaceX have alternative splash down sites ready, aside from Panama City, if need be.
“We have been practicing to recover the crews day or night,” Steve Stich, NASA’s Commercial Crew program manager, said shortly before the capsule’s departure.
“The ships have lots of lighting,” helped by “good moonlight,” he said, adding that weather conditions were excellent, with calm seas.
SpaceX boats are expected to reach the capsule about 10 minutes after splashdown.
Astronauts Hopkins, Victor Glover, Shannon Walker and Japan’s Soichi Noguchi went to space last November as the crew on the first fully operational mission to the ISS aboard a vehicle made by Elon Musk’s SpaceX, which has become NASA’s favored commercial transportation partner.
Prior to that, two American astronauts made a test mission to the ISS in May and stayed for two months.
That was the first launch to the ISS from US soil since the end of the Space Shuttle program in 2011. It was also the first crewed mission run by a private company, as opposed to NASA.
Until then US astronauts had caught rides to the ISS aboard Russian spacecraft.


What We Are Buying Today: Grounded

What We Are Buying Today: Grounded
Photo/Supplied
Updated 01 May 2021

What We Are Buying Today: Grounded

What We Are Buying Today: Grounded
  • Grounded is a Saudi brand that promotes the natural energy, and healing and soothing features of gemstones

Modern technology has many practical benefits and helps us keep pace with a fast-changing world, but our smartphones and computers can cause health problems when used excessively.
Grounded is a Saudi brand that promotes the natural energy, and healing and soothing features of gemstones.
Gemstones have long been used throughout human history as a way to achieve natural balance and ward off negative energies in homes. The brand offers glass water flasks with 11 types of gemstones, including citrine, smoky quartz, obsidian, green fluorite, ruby zoisite, lapis lazuli and amethyst.
Each stone promises an array of special healing qualities relevant to your lifestyle.
Flasks are half a liter in size, and feature a gemstone shaped like an obelisk that helps radiate calming energies.
One ancient way to preserve the beneficial properties said to be present in natural minerals is through the use of pottery vessels. Stone is said to restore the vitality and energy of flowing water.
When a gemstone is placed inside a water container, it can radiate the calm energy of the surrounding water and bring tranquility to your home, Grounded says.
If you are interested in the world of natural energy you can find more details about the benefits of each gemstone through the Instagram account @grounded.232.


Encrypted chat app Signal alleges flaws in Cellebrite equipment

Encrypted chat app Signal alleges flaws in Cellebrite equipment
Updated 22 April 2021

Encrypted chat app Signal alleges flaws in Cellebrite equipment

Encrypted chat app Signal alleges flaws in Cellebrite equipment

WASHINGTON: Encrypted chat app Signal suggested in a blog post published on Wednesday that products sold to law enforcement from Israeli surveillance provider Cellebrite can easily be sabotaged.
Cellebrite DI Ltd, which specializes in helping law enforcement and intelligence agencies copy call logs, texts, photos and other data off of smartphones, has repeatedly come under fire for past sales to authoritarian governments, including Russia and China.
Signal, a privacy-focused app eager to show the lengths it goes to protect users’ conversations, clashed with Cellebrite last year when the Israeli company said its equipment was upgraded to allow law enforcement to scoop up Signal messages from devices in their possession.
Signal creator and CEO Moxie Marlinspike said in his blog post on Wednesday he had come into possession of a bag of Cellebrite equipment and examined the gear inside.
He was “surprised to find that very little care seems to have been given to Cellebrite’s own software security,” Marlinspike said, noting it would be easy to add a specially crafted file onto a phone that would derail Cellebrite’s functionality.
In a statement, Cellebrite did not directly address Marlinspike’s claim but said that the company’s employees “continually audit and update our software in order to equip our customers with the best digital intelligence solutions available.”
Elsewhere in his blog post, Marlinspike alleged he had found snippets of code from Apple Inc. inside Cellebrite’s software, something he said “might present a legal risk for Cellebrite and its users” if it was done without authorization.
Apple did not immediately respond to a request for comment.
Signal’s allegations come as Cellebrite prepares to go public through a merger with a blank-check firm, valuing the equity of the combined company at around $2.4 billion. 


American, Russians dock at ISS in flight honoring first man in space

American, Russians dock at ISS in flight honoring first man in space
Updated 10 April 2021

American, Russians dock at ISS in flight honoring first man in space

American, Russians dock at ISS in flight honoring first man in space
  • Launch timed with 60th anniversary of Soviet cosmonaut Yuri Gagarin's historic flight
  • It was also the 40th anniversary of the first launch of NASA’s space shuttle

MOSCOW: A trio of Russian and American space travelers launched successfully and reached the International Space Station on Friday.
NASA astronaut Mark Vande Hei and Russian cosmonauts Oleg Novitskiy and Pyotr Dubrov blasted off as scheduled at 12:42 p.m. (0742 GMT, 3:42 a.m. EDT) aboard the Soyuz MS-18 spacecraft from the Russia-leased Baikonur launch facility in Kazakhstan.
They docked at the station after a two-orbit journey that lasted just over three hours.
It is the second space mission for Vande Hei and the third for Novitskiy, while Dubrov is on his first mission.
The launch came three days before the 60th anniversary of the first human flight to space by Soviet cosmonaut Yuri Gagarin and the 40th anniversary of the first launch of NASA’s space shuttle.
“When we started, we were competing with each other and that was one of the reasons we were so successful at the beginning of human space flight,” Vande Hei said at a pre-flight news conference Thursday. “And as time went on, we realized that by working together we can achieve even more. And of course, that’s continuing to this day and I hope that it will continue into the future.”
The three will work on hundreds of experiments in biology, biotechnology, physical science and Earth science.
On the International Space Station, they are joining NASA’s Kate Rubins, Michael Hopkins, Victor Glover and Shannon Walker, Russians Sergey Ryzhikov and Sergey Kud-Sverchkov and Japan Aerospace Exploration Agency astronaut Soichi Noguchi.
Rubins, Ryzhikov and Kud-Sverchkov arrived in a Soyuz ship in October; Hopkins, Glover, Walker and Noguchi — the crew of the SpaceX Crew Dragon Resilience — joined them in November.


NASA’s Ingenuity helicopter dropped on Mars’ surface ahead of flight

NASA’s Ingenuity helicopter dropped on Mars’ surface ahead of flight
Updated 04 April 2021

NASA’s Ingenuity helicopter dropped on Mars’ surface ahead of flight

NASA’s Ingenuity helicopter dropped on Mars’ surface ahead of flight
  • The ultra-light aircraft had been fixed to the belly of the Perseverance rover, which touched down on the Red Planet on February 18

WASHINGTON: NASA’s Ingenuity mini-helicopter has been dropped on the surface of Mars in preparation for its first flight, the US space agency said.
The ultra-light aircraft had been fixed to the belly of the Perseverance rover, which touched down on the Red Planet on February 18.
“MarsHelicopter touchdown confirmed!” NASA’s Jet Propulsion Laboratory tweeted Saturday.
“Its 293 million mile (471 million kilometer) journey aboard @NASAPersevere ended with the final drop of 4 inches (10 centimeter) from the rover’s belly to the surface of Mars today. Next milestone? Survive the night.”
A photograph accompanying the tweet showed Perseverance had driven clear of the helicopter and its “airfield” after dropping to the surface.
Ingenuity had been feeding off the Perseverance’s power system but will now have to use its own battery to run a vital heater to protect its unshielded electrical components from freezing and cracking during the bitter Martian night.
“This heater keeps the interior at about 45 degrees F (7 degrees Celsius) through the bitter cold of the Martian night, where temperatures can drop to as low as -130F (-90 degrees Celsius),” Bob Balaram, Mars Helicopter Project chief engineer at the Jet Propulsion Laboratory, wrote in an update on Friday.
“That comfortably protects key components such as the battery and some of the sensitive electronics from harm at very cold temperatures.”
Over the next couple of days, the Ingenuity team will check that the helicopter’s solar panels are working properly and recharging its battery before testing its motors and sensors ahead of its first flight, Balaram said.
Ingenuity is expected to make its first flight attempt no earlier than April 11, the Jet Propulsion Laboratory tweeted.
Ingenuity will be attempting to fly in an atmosphere that is one percent the density of Earth’s, which makes achieving lift harder — but will be assisted by gravity that is one-third of our planet’s.
The first flight will involve climbing at a rate of about three feet (one meter) per second to a height of 10 feet (three meters), hovering there for 30 seconds, then descending back to the surface.
Ingenuity will be taking high-resolution photography as it flies.
Up to five flights of gradual difficulty are planned over the month.
The 1.8-kilogram rotorcraft cost NASA around $85 million to develop and is considered a proof of concept that could revolutionize space exploration.
Future aircraft could cover ground much quicker than rovers, and explore more rugged terrain.