A Dent in the Space-Time
(Note: This TPOD first
ran on March 24, 2006)
What does a dent in the
“fabric” of space and time look like? The cause in a faraway
place is invisible, scientists say. But theorists believe
its existence can be deduced from certain repetitive events.
In January this
year scientists reported that in 2005 two unusual X-ray
frequencies were detected coming from an extremely energetic
light source, GRO J1655-40. The source is seen in the
constellation Scorpius and it is estimated to lie about
10,000 light-years from Earth. Astronomers say it is a
“stellar black hole” about seven times the mass of our Sun,
gradually consuming the matter of a companion star.
seemed strange because scientists had recorded identical
emissions nine years earlier—an improbable coincidence, they
thought. This got them to thinking, and the chain of
reasoning that followed led to a report given at a recent
meeting of the American Astronomical Society.
of the story is a black hole, and black holes are said to
form in the death throes of massive stars as their fuel runs
out and their cores “implode into a point of infinite
density”. The “rebound” that follows produces a supernova
explosion that blows away the outer layers of the star. But
the gravity of the collapsed star is so great that, within a
boundary called the “event horizon”, nothing is able to
escape, not even light. And that’s why we can’t see a black
hole, astronomers say.
say that the gravitational tug of a black hole is sufficient
to distort Einstein’s “space-time fabric”. And that means it
could affect the movement of matter falling into this
emissions from GRO J1655-40 are sporadic—long periods of
relative calm followed by shorter periods of more intense
activity with emissions millions of times greater than
during the quiescent phase.
As reported on
Space.com, some scientists began to wonder if the blinking
pattern of X-ray activity is “related to how matter
accumulates around the black hole”. The black hole is said
to be stealing gas from a companion into an “accretion disk”
around the super-dense relic, and the scientists suggested
that as the mass of the disk accumulates for several years,
the black hole consumes very little of the gas, and X-ray
emissions are minimal.
years, however, something—scientists aren’t sure
what—triggers a sudden binge fest on the part of the black
hole, causing it to guzzle down most of matter in the disk
within a period of only a few months”. This is when the
profusion of X-rays occurs, the scientists suggested. (See “Black
Hole Puts Dent In Space-time”, January 24,
But NASA’s Rossi
X-ray Timing Explorer recorded something curious. Among the
X-ray frequencies observed in 1996 were one at 450 Hz and
one at 300 Hz. The same two frequencies were observed again
very hard to get gas to behave the same way twice, it argues
strongly that these frequencies are being anchored by the
black hole’s mass and spin”, study co-author Jon Miller of
the University of Michigan told SPACE.com.
were reminded of the weird things predicted by Einstein’s
theory of general relativity. “Because the black hole is so
massive and spinning so fast, it warps spacetime around it”.
And the more massive the object, the more spacetime is
distorted. “If the massive object is also spinning, it
causes spacetime to not only bend but to twist as well”.
suggest that the particles moving in “warped spacetime” near
the black hole exhibit two types of motions, each producing
a unique frequency. “One motion is the orbital motion of the
gas as it goes around the black hole. This produces the 450
Hz frequency. The lower 300 Hz frequency is caused by the
gas wobbling slightly due to the spacetime deformations”.
were not curved, we’d probably just see one peak," said
study co-author Jeroen Homan from the Kavli Institute for
Astrophysics and Space Research at MIT.
seemed confident that they were on the right track, and few
astronomers raised objections. "We can now begin to
determine the spin and thus, for the first time, more
completely describe the black hole," Miller said.
photograph above is at best only marginally relevant, we
have tried to be as accurate as possible in paraphrasing the
logic that two scientists applied to the X-ray emissions
from GRO J1655-40. Can you track the number of speculations
in their reasoning? Can you separate what is known from what
is imagined? If this seems difficult, that is because the
language used by scientific media continually confuses fact
The light source
in Scorpius is a fact. So are the sporadic X-ray emissions.
But it may surprise you to hear that everything else
discussed in the report is speculation, unsupported by
anything we can actually study in nature: the star running
out of fuel, the implosion, the rebound, the imploded star,
its “infinite density”, the “spacetime fabric”, the stellar
black hole, the “event horizon”, the companion star, the
siphoning of the companion’s gases, the “accretion” disk,
the “sudden binge fest”, X-ray production by accumulating
matter, the calculated “spin-rate”, the simultaneous
“bending and twisting of spacetime”, X-ray frequencies
linked to orbital motion of gases, and X-ray frequencies
linked to “wobbling” of gases due to “spacetime
So it is not
unreasonable to pose the question: Does the activity of GRO
J1655-40 really imply a “dent in the space-time fabric”? Or
is there a much simpler explanation based on accessible