Page 12 - AT Sept 3 2020
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A12 SCIENCE
Thursday 3 sepTember 2020
Cosmic Legos: Black holes merge into never before seen size
By SETH BORENSTEIN said, but this new discovery
AP Science Writer may offer a clue.
Black holes are getting Perhaps, like playing Legos,
stranger — even to astrono- smaller blocks combine
mers. They've now detect- to make bigger ones and
ed the signal from a long those combine to make
ago violent collision of two even bigger ones, said Har-
black holes that created a vard astronomer Avi Loeb,
new one of a size that had who wasn't part of the
never been seen before. study but said the results
"It's the biggest bang since chart new astronomical
the Big Bang observed by territory.
humanity," said Caltech And indeed the bigger
physicist Alan Weinstein, of the two black holes in-
who was part of the discov- volved in this crash could
ery team. have been the result of an
Black holes are compact earlier merger, both Wein-
regions of space so densely stein and Christensen said,
packed that not even light further bolstering that the-
can escape. Until now, ory.
astronomers only had ob- "It's conceivable that this
served them in two gen- pair of black holes formed
eral sizes. There are "small" entirely differently, possi-
ones called stellar black This illustration provided by LIGO/Caltech in September 2020 depicts two black holes of about 66 bly in a dense system with
holes that are formed and 85 solar masses spiralling into each other to form the GW190521 black hole. Associated Press lots of dead stars whizzing
when a star collapses and about, which allows one
are about the size of small tensen, research director of space that travels at the Weinstein said. "It really black hole to capture an-
cities. And there are super- the French National Centre speed of light. It was that doesn't sound like much on other during a fly by," said
massive black holes that for Scientific Research. wave that physicists in the a speaker." Barnard College astrono-
are millions, maybe billions, Then in May 2019 two de- United States and Europe, This crash happened about mer Janna Levin, who
of times more massive than tectors picked up a signal using detectors called LIGO 7 billion years ago, when wasn't part of the research
our sun and around which that turned out to be the and Virgo, captured last the universe was about and is author of the book
entire galaxies revolve. energy from two stellar year. After deciphering the half its current age, but is "Black Hole Survival Guide."
According to astronomers' black holes — each large signal and checking their only being detected now On the other hand, sci-
calculations, anything in for a stellar black hole — work, scientists published because it is incredibly far entists can't quite explain
between didn't quite make crashing into each other. the results Wednesday in away. Black hole collisions how merged black holes,
sense, because stars that One was 66 times the mass Physical Review Letters and have been observed be- flying around the universe,
grew too big before col- of our sun and the other a Astrophysical Journal Let- fore, but the black holes would meet so many others
lapse would essentially husky 85 times the mass of ters.Because the detectors involved were smaller to to merge again and grow
consume themselves, leav- the sun. The end result: The allow scientists to pick up begin with and even after ever bigger. It could in-
ing no black holes. first ever discovered inter- the gravitational waves as the merger didn't grow be- stead be that supermassive
Star collapses couldn't mediate black hole, at 142 audio signals, scientists ac- yond the size of typical stel- black holes were formed in
create stellar black holes times the mass of the sun. tually heard the collision. lar black holes. the immediate aftermath
much bigger than 70 times Lost in the collision was an For all the violence and Scientists still don't know of the Big Bang.
the mass of our sun, scien- enormous amount of en- drama, the signal lasted how supermassive black "In astrophysics we're al-
tists thought, according ergy in the form of a gravi- only one-tenth of a second. holes at the center of gal- ways faced with surprises,"
to physicist Nelson Chris- tational wave, a ripple in "It just sounds like a thud," axies formed, Christensen Weinstein said.q
Can I use a face shield instead of a mask?
By The Associated Press
Can I use a face shield instead of a mask?
No. Health officials don't recommend the clear plastic barriers as a sub-
stitute for masks because of the lack of research on whether they keep
an infected person from spreading viral droplets to others.
However, those who want extra protection may want to wear a face
shield in addition to a mask.
Face shields have the added benefit of protecting your eyes and dis-
couraging you from touching your face by acting as a physical barrier,
says Christopher Sulmonte, project administrator of the biocontainment
unit at Johns Hopkins Hospital.
Meanwhile, the available research so far indicates that the best face
shields for preventing viral spread are hooded or wrap around the sides
and bottom of the face, according to the U.S. Centers for Disease Con-
trol and Prevention. That's because those shields leave less space for
droplets from sneezing, coughing and talking to escape.
If you do wear a reusable face shield in addition to a mask, the CDC A Congressman Aldo Davila, wearing a face mask and face shield amid the
notes the importance of cleaning it after each use. The agency also COVID-19 pandemic, waits outside the presidential office with Indigenous
leaders, hoping for a meeting with President Alejandro Giammattei in
says you should wash your hands before and after taking it off, and Guatemala City, Friday, Aug. 21, 2020.
avoid touching your face while removing it.q Associated Press