Astronomy

ASTRONEWS

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Astronomers believe that

supermassive black holes at

the centers of galaxies “flicker”

on and off, alternately gob-

bling up material, “burping”

out bubbles of hot gas, and

“napping” between meals. But

while spotting a single out-

burst isn’t rare, identifying the

remnants of two past meals

has never occurred until now.

A team led by researchers at

the University of Colorado

Boulder published such a find

in The Astrophysical Journal

November 6, identifying two

separate burps emitted by the

galaxy SDSS J1354+1327 (or

J1354, for short): one ancient

and on the verge of dissipat-

ing, and one hinting at a more

recent meal.

Because burps dissipate over

time, they become increasingly

difficult to see. “We happened

to observe this galaxy at a time

when we could clearly see evi-

dence for both events,” said

study leader Julie Comerford of

CU Boulder in a press release.

The researchers spotted a

large, diffuse cone of gas

extending 30,000 light-years

below the galaxy’s bulge, where

the supermassive black hole is

located. The atoms in the gas

were stripped of their electrons

by a huge burst of radiation

from the black hole about

100,000 years ago. Above the

bulge, they saw a shock wave

3,000 light-years away from the

black hole, associated with a

second, more recent meal.

Between the two events,

the black hole was likely much

more dormant. “We are seeing

this object feast, burp, and

nap, and then feast and burp

once again, which theory had

predicted,” said Comerford.

That theory also applies to

the Milky Way. “Our galaxy’s

supermassive black hole is now

napping after a big meal, just

like J1354’s black hole has in the

past. So we also expect our mas-

sive black hole to feast again,

just as J1354’s has,” said Scott

Barrows of CU Boulder. — A.K.

Black hole lets out a double burp

SINK IN. The surface of Jupiter’s moon Europa may be so porous

that visiting spacecraft would sink into the world.

BAD MANNERS. Astronomers imaged the galaxy J1354, about

800 million light-years away, in X-rays and optical light. They saw the

remnants of one ancient (blue-green emission) and one more recent

(blue arc) burp. A nearby companion galaxy hints at a galactic collision

that funneled material in toward the supermassive black hole, providing

the meals that prompted those burps.

© YANSOLO | DREAMSTIME.COM

X-RAY NASA/CXC/UNIVERSITY OF COLORADO/J. COMERFORD ET AL.; OPTICAL: NASA/STS

CI

DEATH’S HOT/COLD TOUCH

The four outer planets have

no solid surfaces. If you

started at the top of their

atmospheres, you’d fall for

about a minute (choking all

the way) before the intense

atmospheric pressure

crushed you.

PLANETARY BODY. Science fiction movies sometimes show bad

things happening to spacesuits. Indeed, films like The Martian and Tota l

Recall attempt to visualize what would happen if a suit depressurized.

But how long could an astronaut last without that first level of

protection? Here are some rough estimates. — Michael E. Bakich

Earth

71.4 years

(average)

Mars

2 minutes

Jupiter, Saturn,

Uranus, and

Neptune

1 minute

Venus

1 to 2 seconds

Mercury

30 seconds

X-ray & optical

New

burp

Old burp