The Week USA 03.20.2020

Health & Science NEWS^21

Forests won’t stop climate change

The world’s tropical forests are rapidly los-

ing their ability to soak up carbon dioxide

from the atmosphere, a worrying develop-

ment that could accelerate climate change,

reports The Guardian (U.K.). In a new

study using data from 565 tropical forests

across Africa and the Amazon, an inter-

national team of researchers found that

the forests’ intake of carbon peaked in the

1990s. In the past decade, they’ve absorbed

a third less—a difference of 23 billion tons,

or about the same as a decade of fossil fuel

emissions from the U.K., Germany, Canada,

and France combined. Forests lose their

ability to soak up carbon as trees dry out

and die from droughts and higher tempera-

tures, but the greatest threats to rain forests

are logging, burning, and other forms of

human activity. If the Amazon—the world’s

largest tropical forest—continues to degrade

at its current rate, researchers believe, it will

turn from a carbon sink to a source of emis-

sions by 2035. “Humans have been lucky so

far, as tropical forests are mopping up lots

of our pollution, but they can’t keep doing

that indefinitely,” says senior author Simon

Lewis, from Leeds University in the U.K.

Was Earth a water world?

Our blue planet may have been a whole lot

bluer some 3 billion years ago, devoid of

continents and almost entirely covered by

a global ocean. That’s the conclusion of a

new study that examined an ancient chunk

of ocean-bed crust that now sits on its side

in the Australian outback. The researchers

examined the levels of two different isotopes

of oxygen that seawater carried into the

slab: Oxygen-16 and the slightly heavier

atom Oxygen-18. After studying more than

100 rock samples, they determined that

seawater contained more Oxygen-18 when

the crust was formed 3.2 billion years ago.

Today, land masses across Earth soak up

heavier oxygen isotopes from water and lock

them in clay-rich soils. The scientists suspect

that the ancient ocean crust contains higher

levels of Oxygen-18 because there were no

soil-covered continents to absorb it. Study

co-author Boswell Wing, from University

of Colorado, Boulder, tells CNN.com that

“teeny micro-continents” that resembled the

Galapagos Islands might have stuck out of

this ancient ocean. “We just don’t think that

there was global-scale formation of conti-

nental soils like we have today.”

Dogs’ heat-seeking noses

Scientists may have solved one of the great

mysteries of the animal kingdom, reports

ScienceMag.org: why dogs have cold, wet

noses. Most mammals have smooth, dry

skin around the edges of their nostrils, an

area known as the rhinarium. But dogs rhi-

naria are moist, colder

than the ambient

temperature, and

packed with nerves.

Vampire bats have

cool patches near

their noses that act

as heat detectors, so

researchers in Sweden

and Hungary won-

dered if canine rhinaria

might work in a similar

way, helping them track

warm-blooded prey. To

test this theory, scientists

trained three pet dogs to identify which of

two identical 4-inch wide objects had been

warmed to about 22 degrees Fahrenheit

above room temperature. All of the dogs

were able to identify the hotter object at a

distance of 5 feet. Scientists then scanned

the brains of 13 dogs as they were exposed

to a warm object and one kept at room

temperature. Sure enough, the part of the

brain linked to the dogs’ noses became more

active when the pooches were shown the

warm object. “It’s a fascinating discovery,”

says Marc Bekoff, an expert on canine sniff-

ing at the University of Colorado, Boulder,

who wasn’t involved in the study. It “pro-

vides yet another window into the sensory

worlds of dogs’ highly evolved cold noses.”

Health scare of the week

Thirdhand smoke exposure

Nonsmokers who carefully avoid going

anywhere where people light up can still

be exposed to the negative health effects of

cigarette smoke, warns a new study from

Yale University. It found that chemicals

from tobacco smoke can infiltrate nonsmok-

ing rooms by hitching a ride on smokers’

clothes, skin, and hair and then evaporating

into the air. To discover how so-called third-

hand smoke can spread, the researchers put

an air-sampling device in a cinema that has

enforced a smoking ban for 15 years—long

enough for any pre-ban contaminants to

have cleared out. Over four days, they

observed sharp spikes in 35 tobacco-

related chemicals—including cancer-

causing compounds such as benzene

and formaldehyde—when audience

members entered the theater. Although

the room was well-ventilated, by the end

of the movie patrons had breathed in the

equivalent of the secondhand smoke from

up to 10 cigarettes. Lead author Drew

Gentner tells Agence France-Presse that he

hopes the study “will generate much-needed

Cha discussion about thirdhand smoke.”

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Astronomers have detected what might be

the biggest explosion in the universe since

the Big Bang—a colossal blast that blew a

hole the size of 15 Milky Ways in the sur-

rounding space. The explosion happened

a few hundred million years ago in the

Ophiuchus galaxy cluster, 390 light-years

from Earth. Such clusters contain thou-

sands of galaxies intermingled with hot

gas and dark matter. Near the heart of the

Ophiuchus cluster is a large galaxy with a

supermassive black hole. Although black

holes are known for sucking in matter, they

can also push out phenomenal amounts

of material, reports CBSNews.com. In this

case, researchers believe the black hole

shot out a jet of material at close to the

speed of light, which then hit something in

space and exploded, releasing five times

more energy than any previously known

blast. Signs of the explosion were first

detected in 2016 by NASA’s Chandra X-ray

Observatory, which spotted an unusual

curved edge in the cluster’s hot gas—

possibly part of a cavity formed by a blast.

Using X-ray and radio telescopes, a new

team of scientists has now determined

that the curved edge is indeed the bound-

ary of an enormous blast cavity. “This has

been like discovering a dinosaur,” say

study co-authors Simona Giacintucci and

Maxim Markevitch, “with just a little piece

(the unusual X-ray edge) sticking out at

first and then suddenly a new kind of crea-

ture coming out from the ground.”

An explosion that left a dent in a galaxy

Deforestation in the Amazon

The Ophiuchus cluster: Site of a big bang