Black holes are becoming stranger — even to scientists who study planets and other objects in outer space.
Astronomers recently reported the discovery of the signal from a violent collision of two black holes. The event, which took place long ago, created a new black hole of a size that scientists had never seen before.
California Institute of Technology physicist Alan Weinstein was part of the discovery team. He noted that the finding was the “biggest bang” ever observed by human beings since the Big Bang.
The Big Bang is a term many astronomers use to explain the beginning of the universe.
Black holes are compact areas of space. They are so dense that not even light can escape. Until recently, astronomers had observed them in two general sizes.
There are “small” ones called stellar black holes. These black holes are formed when a star collapses. They are about the size of a small city.
There are also supermassive black holes. These black holes are millions, maybe billions, of times more massive than our sun.
Astronomers’ calculations suggest that anything in between the two sizes did not make sense. That was because stars that grew too big before collapse would generally destroy themselves, leaving no black holes.
Nelson Christensen is research director of the French National Centre for Scientific Research. He says scientists thought that star collapses could not create stellar black holes much bigger than 70 times the mass of our sun.
Then in May 2019 two sensors received a signal that turned out to be the energy from two stellar black holes crashing into each other. One was 66 times the mass of our sun. The other was 85 times the mass of the sun.
The result: The first ever discovered intermediate black hole, at 142 times the mass of the sun. The word intermediate suggests being in the middle of a process or development.
In the collision, a large amount of energy was lost. The energy was in the form of a gravitational wave, a ripple in space that travels at the speed of light.
It was that wave that physicists in the United States and Europe, using detectors called LIGO and Virgo, captured last year. After studying the signal and reexamining their work, scientists published the results this week in Physical Review Letters and Astrophysical Journal Letters.
Because the detectors receive the gravitational waves as audio signals, scientists actually heard the collision. For all the violence, the signal lasted only one-tenth of a second.
“It just sounds like a thud,” Weinstein said. “It really doesn’t sound like much on a speaker.”
This crash happened about 7 billion years ago, when the universe was about half its current age. It was only detected now because the collision was so far away.
Black hole collisions have been observed before. But the black holes involved were smaller to begin with. Even after the collision, they did not grow beyond the size of normal stellar black holes.
Scientists still do not know how supermassive black holes at the center of galaxies formed, Christensen said, but this new discovery may offer a clue.
I’m John Russell.
Seth Borenstein reported on this story for The Associated Press.John Russell adapted it for VOA Learning English. George Grow was the editor.
Words in This Story
collision – n. an act of colliding, such as a crash in which two or more things or people hit each other
bang – n. a sudden, loud noise
compact – adj. closely or firmly joined together
calculation – n. an estimate or prediction
ripple – n. something that passes or spreads through or over someone or something; a shape having small waves
detector – n. a device that can tell if a substance or object is present; a device that measures the presence of something
thud – n. a loud sound made especially when a heavy object hits something
Lunar Surface Radiation Measurements Show Moon Is Safe for Long-Term Human Exploration – Science Times
Moon is safe for human exploration according to the first detailed radiation measurements on the lunar surface by China’s Chang’e 4 lander. The data will be used by future researchers in determining how much protective shielding is needed to protect future crews.
Past missions of Apollo during the ’60s and ’70s have failed to capture the radiation exposure of the mission while on the Moon’s surface because the dosimeters they carried recorded the total exposure from their entire journey. Since then, scientists have had to estimate levels of radiation on the crew while on the Moon from extrapolation and modeling.”
Measuring Radiation Levels on the Lunar Surface
NASA is planning to put humans back on the Moon by 2024 with its new lunar mission called Artemis. Likewise, the China National Space Administration is also eying human explorations on the lunar surface by the 2030s. China’s Chang’e 4 lander made history in 2019 when it successfully landed on the Moon’s Von Kármán crater.
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Chang’e 4 has brought along instruments which include a new dosimeter operated by study co-author and physicist Robert Wimmer-Schweingruber of the University of Kiel, and his colleagues in China and Germany.
The new dosimeter measures the hourly radiation rates on the lunar surface and found that astronauts would be exposed to roughly 200 times the radiation levels people get on Earth.
Wimmer-Schweingruber said that the results of the measurements are relatively applicable to human explorers because the dosimeter is placed inside the probe of Chang’e 4proving a partial shielding like how their spacesuit protects astronauts.
He also said that they could measure radiation levels five to ten times of what passengers of an intercontinental flight from New York to Germany receive when flying above the protective atmosphere.
Protecting Future Moon bases
The measurements they got from Chang’e 4 lander were used to calculate the amount of protection future Moon bases would need. They estimated that at least 50 centimeters of regolith would be sufficient to protect them. Additionally, at least 10 meters of water shielding a deeper chamber would be enough to protect against solar storms that can cause a dramatic spike on radiation levels.
The new dosimeter measured both charged and neutral particles. Charged particles are those protons and heavy nuclei that have been stripped off their electrons, which are considered hazardous because it can penetrate human skin and damage the DNA, which then leads to cancer and other health conditions.
The charged particles come from two primary sources: the powerful solar flares and a constant rain of galactic cosmic rays from space.
Furthermore, the Moon does not have a magnetic field to deflect radiation, unlike the Earth. When radiation hits the lunar surface, neutral particles are sprayed over the Moon, which penetrates deeper than the charged particles and can wreak havoc on other cells.
Francis Cucinotta said that the results were already expected. Still, it is good to have specific measurements that verify astronauts can be safe in shielded bases and spend six months on the Moon without exceeding NASA’s legally mandated limits.
Check out more news and information on the Moon Exploration on Science Times.
Researcher Discusses Whether or not Time Journey May Stop a Pandemic – Editorials 360
College of Queensland pupil Germain Tobar who labored with UQ physics professor Fabio Costa on a brand new peer-reviewed paper “says he has mathematically confirmed the bodily feasibility of a selected type of time journey” with out paradoxes, experiences Common Mechanics:
Time journey dialogue focuses on closed time-like curves, one thing Albert Einstein first posited. And Tobar and Costa say that so long as simply two items of a complete state of affairs inside a closed time-like curve are nonetheless in “causal order” once you go away, the remaining is topic to native free will… In a college assertion, Costa illustrates the science with an analogy
“Say you travelled in time, in an try and cease COVID-19’s affected person zero from being uncovered to the virus. Nevertheless for those who stopped that particular person from changing into contaminated, that will remove the motivation so that you can return and cease the pandemic within the first place. This can be a paradox, an inconsistency that usually leads folks to suppose that point journey can not happen in our universe. [L]ogically it is exhausting to just accept as a result of that will have an effect on our freedom to make any arbitrary motion. It might imply you may time journey, however you can’t do something that will trigger a paradox to happen….”
However the actual fact, by way of the mathematical outcomes, is extra like one other traditional parable: the monkey’s paw. Watch out what you would like for, and watch out what you time journey for. Tobar explains within the assertion:
“Within the coronavirus affected person zero instance, you may attempt to cease affected person zero from changing into contaminated, however in doing so you’ll catch the virus and turn out to be affected person zero, or another person would. It doesn’t matter what you probably did, the salient occasions would simply recalibrate round you. Attempt as you may to create a paradox, the occasions will at all times regulate themselves, to keep away from any inconsistency.”
Learn extra of this story at Slashdot.
UPI Almanac for Sunday, Sept. 27, 2020 – UPI News
Today is Sunday, Sept. 27, the 271st day of 2020 with 95 to follow.
The moon is waxing. Morning stars are Jupiter, Mars, Neptune, Saturn, Uranus and Venus. Evening stars are Jupiter, Mars, Mercury, Neptune, Saturn and Uranus.
Those born on this date are under the sign of Libra. They include statesman Samuel Adams in 1722; political cartoonist Thomas Nast in 1840; magician Harry Blackstone Sr. in 1885; actor Jayne Meadows in 1919; filmmaker Arthur Penn in 1922; actor William Conrad in 1920; actor Wilford Brimley in 1934; golf Hall of Fame member Kathy Whitworth in 1939 (age 81); rock musician Randy Bachman in 1943 (age 77); singer Meat Loaf, born Michael Lee Aday, in 1947 (age 73); baseball Hall of Fame member Mike Schmidt in 1949 (age 71); actor/singer Shaun Cassidy in 1958 (age 62); gold medal-winning speed skater Beth Heiden in 1959 (age 61); actor Gwyneth Paltrow in 1972 (age 48); rapper Lil Wayne, born Dwayne Michael Carter Jr., in 1982 (age 38); actor Anna Camp in 1982 (age 38); singer Avril Lavigne in 1984 (age 36); actor Thomas Mann in 1991 (age 29); actor Jenna Ortega in 2002 (age 18).
On this date in history:
In 1540, the Society of Jesus, known as the Jesuits, was chartered by the Roman Catholic Church.
In 1825, in England, George Stephenson operated the first locomotive to pull a passenger train.
In 1930, golfer Bobby Jones won the U.S. Amateur Championship, capturing the era’s Grand Slam. Earlier in the year, he won the British Amateur, British Open and U.S. Open.
In 1938, Queen Elizabeth christened the world’s largest ocean liner with her own name during a ceremony in Scotland. The Queen Elizabeth was the sister ship of the Queen Mary, which was christened four years earlier.
In 1939, after 19 days of heavy air raids and artillery bombardment, Polish defenders of Warsaw surrendered to German forces.
In 1954, The Tonight Show made its television debut with host Steve Allen.
In 1964, the Warren Commission report on the assassination of President John F. Kennedy was released after a 10-month investigation, concluding that there was no conspiracy and that Lee Harvey Oswald, the accused assassin, acted alone.
In 1998, Gerhard Schroeder led Germany’s Social Democratic Party to victory in parliamentary elections, bringing to an end 16 years of power by Chancellor Helmut Kohl and his Christian Democratic Party.
In 2008, Zhai Zhigang left the Shenzhou VII spacecraft and became the first Chinese astronaut to take a space walk.
In 2010, Jimi Heselden, 62, manufacturer of the upright Segway scooter, was killed when he apparently lost control of one of the two-wheeled, self-balancing machines and ran over a cliff into a river.
In 2014, Mount Ontake, Japan’s second highest volcano, erupted in a cloud of ash, killing 63 people, many of them hikers.
In 2017, Thailand’s Supreme Court ruled unanimously to sentence former Prime Minister Yingluck Shinawatra to five years in prison for failing to report false and corrupt government-to-government sales in a rice-pledging scheme.
In 2018, India’s top court said a colonial-era law that criminalized adultery was unconstitutional and discriminatory in a landmark ruling hailed by women’s rights groups.
A thought for the day: “The single story creates stereotypes, and the problem with stereotypes is not that they are untrue, but that they are incomplete. They make one story become the only story … The consequence of the single story is this: It robs people of dignity.” — Nigerian author Chimamanda Ngozi Adichie
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