A black hole life preserver

The link for this story is:
http://www.dallasnews.com/health/columnists/tsiegfried/stories/091503dnl
ivtomco
l.33516.html

I think you have to register to view these stories so I thought I would
just 
post it for everyone to read (I work at The Dallas Morning News so I'm
not 
going to feel guilty for posting the whole thing :-)

I have to give Tom kudos for the Highlander reference.

Doughnut can delay death for black hole tourist 

By TOM SIEGFRIED / The Dallas Morning News 

When you toss an endangered swimmer a life preserver, you should really
call it 
a death delayer. 

After all, nobody lives forever, except the Highlander, and even he'd be
in 
trouble if he fell into a black hole. 

Today's question is, when the Highlander dives into a black hole, is
there any 
point in providing him with a death-delaying life preserver? And the
answer, 
actually, is yes, say J. Richard Gott III and Deborah Freedman. 

Dr. Gott, of Princeton University, and Ms. Freedman, of Harvard, have 
calculated a way to prolong your life, or at least reduce your agony, as
a 
black hole's gravity sucks you in and rips you to shreds. You just need
to 
surround yourself with a gigantic electrically charged doughnut. 

If you fall into a black hole unprotected, gravity draws all parts of
your body 
toward the center of the black hole. So your left side will be pulled to
the 
right and your right side to the left. If you go in feet first, the 
gravitational pull will be much stronger on your shoes than your head,
tending 
to make you instantly thinner and taller. 

"It is like being stretched on a rack and simultaneously crushed in an
iron 
maiden," the two researchers write in a new paper submitted to the
journal 
Physical Review D. 

Such gravitational (or "tidal acceleration") forces don't hurt, up to a
point. 
Fighter pilots can withstand forces up to 9 G's or so – nine times the
normal 
pull of gravity. 

"But beyond 10 G's, the tidal acceleration will cause pain and
dismemberment," 
the scientists write in their paper, available on the World Wide Web at 
xxx.lanl.gov/abs/astro-ph/0308325. 

So at some point, your journey to the black hole's center will turn into

painful torture. 

(Actually, the torture can begin even before you reach the black hole's
outer 
boundary, the event horizon. For large black holes – greater than
13,800 times 
the mass of the sun – crossing the event horizon remains within the
acceptable 
range of G-forces. But small black holes have masses of only a few suns.
For 
those, you'll start stretching before you cross the border.) 

Anyway, the good news is that the time of torture passes pretty quickly.
In 
fact, from the start of the pain to getting crunched out of existence 
altogether comes to less than a 10th of a second, the scientists
calculate. 

But a life preserver – er, death delayer – can prolong your pain-free
travel 
time and make the torture time even shorter. 

It has to be big – about the size of one of Saturn's rings and the mass
of a 
large asteroid. But when diving into a black hole with this huge ring 
surrounding you, the pull of the ring on you will cancel the pull of the
black 
hole. 

As you fall closer to the black hole's center, its pull on you
increases. But 
the black hole tugs on the ring, too, compressing it so that more of its
mass 
is closer to you. So the ring's pull on you increases, counteracting the
black 
hole's efforts to crush you. 

"Your head is being pulled downward by that ring, and your feet are
being 
pulled upward, so it just counters the tidal force that the black hole
is 
giving," Dr. Gott said in a telephone interview. 

To keep the ring from collapsing under its own weight, it must be
electrically 
charged (electrical repulsion counters the ring's self-gravity).
Unfortunately, 
the electrical fields would fry you, so you need to encase yourself in a

protective container known as a Faraday cage. But that's pretty simple
compared 
to making the giant doughnut to begin with. 

If all works well till then, the ring can keep you comfortable up to
6,760 G's. 
After that you'd be tortured for a mere three one-thousandths of a
second. 

"You really wouldn't know what hit you," Dr. Gott and Ms. Freedman
write. 

If that still bothers you, you can reduce the torture time even more.
Instead 
of falling in feet first, assume the fetal position. Then align the line

connecting your shoulders so it points toward the black hole's center.
With a 
ring suitably adjusted for your new size, you can reduce the torture
time to 
less than two one-thousandths of a second. 

Of course, another approach to avoiding such torture is simply staying
away 
from black holes. But that's not very much fun. And having fun with
black holes 
is what such exercises are all about. 

"This business that you're ripped apart when going into a black hole is 
something that's said in every astronomy book," Dr. Gott said. "We just 
wondered if there was something you could actually do about it." 

The calculations in the Gott-Freedman paper can be grasped by a bright
high 
school student; these death-delaying scenarios offer insights into the
basics 
of Einstein's general relativity and fundamental principles of physics. 
Analyzing such seemingly silly situations can give students – and
scientists – 
a more tangible grasp of what nature is really like in realms outside 
earthbound experience. 

Besides, there really could be practical applications someday, when 
interstellar travelers want to explore black holes or perhaps neutron
stars. 
Maybe some sort of doughnutlike death delayer would help keep you alive
when 
encountering such objects. 

"An adjustable-radius, actively oriented life preserver might enable you
to 
venture closer than would otherwise have been the case," the scientists
write, 
"and still return safely home from the adventure."