The Galactic Heavy Metal
Transit System
(Survival-astrophysics for the common man)
Copyright 1998: Larry Leonard
"I mean, why not? All you're talking about is the mathematical
equivalent of parallel mirror image Hawking/Gnikwah universes which interchange
Dilbert-mass for Frohmm-energy and vice versa at an infinite number of
identical but sign-opposite pointillistic cosmic quantum-duality intersections!"
There was this toy car lurching across the surface of mars ...
The way it ran into things, one wondered if the computer that was directing
it would pass a breathalyzer test. The Russian MIR space station
has more plumbing problems than a south Bronx apartment. And, the
Apollo 13 lads only made it back because they had plenty of duct tape.
Why are we spending billions out "there?" What's the fascination?
And, considering the fact that if you run out of duct tape, it's just as
dangerous as quoting Rush Limbaugh at a NOW meeting, why would anybody
risk going there?
We'll start with the "why."
A few years ago, a multi-university group of
astronomers working with the 88" reflector telescope on Mauna Kea (a mountain
in Hawaii) were studying space when they found a strange object that wasn't
Al Gore. It is circling two colliding galaxies at two million miles
per hour, and is sizeable -- perhaps 100 million times the mass of our
sun. It may even weigh in a thousand times bigger than that and so
have the same mass as our entire galaxy, the Milky Way!
What, besides a copy of the U.S. tax code,
could weigh this much?
The problem you run into on jobs like these
is that the envelope of gasses around our planet acts a lot like the cigar
smoke in an old-west cardroom, God Bless both. It distorts some kinds
of radiation, and even flat stops some other kinds. (If it didn't,
you'd be dead.) That's one reason why we have to get out there.
Orbiting astronomical devices like the Hubble Space Telescope (modified
in February, 1997 to, among other things, make it into a black-hole-a-scope)
are by definition far above the madding clouds.
Not that we've given up trying to get a better
look from down here.
VLBI (Very Long Baseline Interferometry, or
widely-spaced smaller astronomical observation machines working in tandem
to simulate a single device of the same overall size) is in its early stages
here on earth. This type of scope usually works with equipment that
looks like a satellite TV dish, and which "sees" parts of the electromagnetic
spectrum other than visible light.
(60 inch Hale optical at Mt. Wilson and a radio telescope
dish)
The idea may hold great promise. We're
even planning on experimenting with this technique in space, which offers
the potential of RLBI, or Ridiculously Long Baseline Interferometry.
(For a comparison, the best optical scopes we've got have the
theoretical capability to see, from Los Angeles, a man waving in San Francisco.
Think of the Hubble as being able to see the same guy in Moscow.
Earth-based VLBI has the potential to see him waving from the moon.
A VLBI in space may be able to see him standing on, for example, Saturn's
moon, Titan. It could observe planets circling stars ten light years
distant.)
Besides the already mentioned mystery-whopper-meets-the-colliding-galaxies,
what else will we be looking for?
One task might be figuring out what Gamma
Ray Bursters are. These sudden emission points of the most energetic
kind of radiation were once thought to be the result of a collision between
two dead stars, say John Wayne and Orson Welles The short term energy
release is impressive. It equals the total output of our sun over
its predicted lifespan.
Recently, the observation of two such bangs
in the same vicinity seems to have killed the dead star collision theory,
since the odds of two pairs doing it in the same neighborhood within a
couple of days are, well, astronomical.
Another task will be that of taking a long
look at the beginning of the universe. Telescopes, according to every
astronomy program ever produced, are time machines. The farther out
you look, the farther back in time you're looking. (Indians called astronomers
"the men with long eyes.")
This is true, but misleading. Telescopes don't
"look out." They collect light or some other kind of radiation.
The best ones are the best at collecting light, and so manage to "see"
the faintest objects. The faintest objects are the farthest away,
and so the light has taken longer to get here. It began to come towards
us at an earlier time than the light from nearer objects, and so represents
a source from deeper in our past. Our sun is nine "light minutes"
away. The object you see in the sky is the sun that existed nine
minutes in the past. If it blew up as you are reading this sentence,
you wouldn't know it, nobody would know it, for that length of time.
This is what astrophysicists mean when they talk about the "event horizon."
(A nice side effect of this bit of science
is that you can now understand why you think you are the center of the
universe. The fact is: you are! Everything around you started
sending its light to you in your past. You are the only "present"
item, anywhere.)
Yet another question to answer is why galaxies
weigh more than they should. We know this because the galaxies, many
with a goodly percentage of stars like our sun in them, spin wrong.
That is, the outer stars orbit at higher velocities than they should. Galactic
components (stars), unlike the planets in our solar system, keep their
place. Their outer stars seem to be on the end of spokes connected
to the center. (M100, below, is a spiral similar to our galaxy, the
Milky Way. Our sun, Sol, is located about 2/3 of the way out an arm like
those you can see here.)
It's almost as if the galaxies are like terrestrial
planets ... with the surface always over the same spot in the core.
(Ignoring the possibility, of course, that Earth's core, a giant ball bearing
made of super-iron that is floating inside a sphere of liquid iron, might
be rotating at a different speed than we on the surface are spinning.
We do live on an electromagnet, after all.)
Gravity has to be the agent of this strange galactic
spin problem. But, gravity is an effect related to mass. When
you add up all of the matter that we can visually observe, the total works
out to be less than a tenth of that neccessary to do the job. That
means that galaxies have more mass than we can see.
Cosmic dust was once suspected. Next came
neutrinos, which are atomic particles that can pass through ten miles of
solid lead without slowing down. "Observatories" under mountains,
which slow down most other particles, haven't come up with much that supports
this idea, so far.
(News! In May of this year, the experiment
at Kamioka, Japan, established that the neutrino has mass! How much
is yet to be determined.)
Whatever it is, the astronomers have named
this mass we can't see: cold dark matter. (Sounds like a medieval
romance novel, doesn't it?) A friend of Cambridge University Lucasian
Professor, Stephen Hawking, a fellow working in the state of Washington,
proposed that this stuff might be floating around in clumps he called MACHOs,
or MAssive Cosmic Halo Objects. Relativity theory, which we will
get into in more depth later, says that if there are such things they would
make a kind of light-lens in space-time. (A galactic cluster gravity
lens is shown, later.) Stars behind them would appear to flare up, get
brighter, until they passed by. The fellow, named Stubb, actually discovered
that MACHOs exist, but, sadly, came to the conclusion that there can't
be enough of them to account for the galactic spin problem. These
days, some folks are down in the bottom of mile-deep mine shafts,looking
for WIMPs, a name that stands for Weakly Interactive Massive Particles.
But, because of Kamioka, muons, the subatomic particle
from which black cats are made, are now the best bet. They can't
be seen when they don't want to be seen because they flit in and out of
the light. They're charged, as you know if you've ever petted one.
And, they're sneaky.
You might be saying, "Well, this is all interesting, but
why should I care about it?"
Actually, if you're both a back-to-agricultural-existence
hippie and an atheist, it'll never matter (pun intended) to you, at all,
so you probably shouldn't care. But, cold dark matter, after you
run the numbers, represents ninety-percent or more of the universe.
For those interested in the subject, that means a good estimate of its
actual mass total would tell them the future of the universe. (And its
past.)
Here's how that works.
Over a certain number, the universe will stop expanding,
begin contracting and finally end up in a Big Crunch -- a nice symmetry
when matched with the original Big Bang. Under the critical mass
number, the universe will continue expanding, cooling and decaying until
it's just a mass of subatomic particles with nothing to do but watch reruns
of Sixties television sitcoms. (For the non-atheists, the first version
needed God to kick it into gear, but runs without Him afterwards.)
Muons aside, I have suggested to a number
of professional stargazers that there is a kind of dark matter that fits
the requirements, and which has been ignored by them -- since the stuff
is heavy, and black, it could be 1953 Buicks.
But, the answer, in the end, might be all of the
above and more. And, what might tip the scale one way or the other
(to the frozen eternal damnation of universal heat death or, joy of joys,
the eternal recreation of worlds without end) is the number of black holes.
Stellar Sumo Objects, I calls them, since a teaspoonful of black hole material
can weigh a billion tons.. Even without the galactic missing mass
problem, though, they'd study these babies. Black holes, sometimes
referred to as "iron suns," are definitely fascinating "things."
You'll understand soon why I put quotes around that word. Black holes
are strange.
Disney did a movie on the subject about the
time the Beatles discovered universal consciousness, books have been written
about it; in fact, it's probably one of the few astronomical topics of
which the general populace is even aware. (Especially since Stephen
Hawking's Universe mini-series hit PBS.) Most people can't even name the
nearest star, which happens to be the Sun. Most people think the
Dog Star is Lassie. (Or Benji.) Most people think Planck's Constant
is slivers. And, you could spend your life walking the streets of
New York looking for someone who could name a famous observational astronomer
who had a metal nose, or a legendary theoretical astronomer whose mother
was tried as a witch.* (Answers at the end of this article.)
So, since you have personally hocked your
future by financing the space program you might as well know a little about
what the machines that you didn't know you were paying for are going to
observe about what you didn't know you were looking for, which, by the
way, can't be seen because as every physicist knows, Relativity-ly speaking,
it isn't there.
Put simply, a black hole (also called a collapsar)
is a stellar object whose gravitational effect is so great that even light,
the fastest stuff/thing in the universe, cannot escape from its immediate
vicinity. Think of it as an invitation to dinner at your fiance's parent's
house. There's just no way out.
(Well, sort of. Nothing, unfortunately, can
escape a black hole. And, if you ever actually understand what I
just said, you'll be put in either a university physics lab or a home for
the mentally deranged. There is no real difference between the two
these days.)
So, getting beyond the question of the overall
fate of the universe, why do astronomers and physicists give a hoot about
the things?
It seems likely, even to a few stable scientists,
of which there must be some, that these dinguses may offer a way out of
a trap that Einstein set for our astronauts at the other end of this century.
They could even ultimately provide a mechanism for the survival of the
human race; assuming, of course, that that is a desirable thing.
(It will, in any event, become a problem in
some four or five billion years, when the sun's atmosphere expands to envelop
all of our solar system's inner, or terrestrial, planets. This event may,
as well, be abetted by the collision of our galaxy with another galaxy.
There is, in other words, trouble ahead for our descendants.)
(Albert Einstein)
The history of interest in black holes is inextricably
tied to some very special people. Most important of these is Albert
Einstein. Because of his Special (1905) and General (1916) Theories
of Relativity, we may both need and be able to understand black holes.
This is not to say Einstein first proposed them, however. Some two
hundred years ago, a fellow named, Laplace, leaping from Newton's shoulders,
conjectured the existence of stars so large that their gravity denies even
the escape of light itself. This, of course, had to be based on the
supposition that light has mass; an opinion widely supported at that time
because it was the opinion of the Greatest Scientist Who Ever Lived, Sir
Isaac Newton (1642-1727).
But, it was Einstein's thought-experiments
and equations about beyond-Newtonian stuff that kicked the modern interest
in these things into gear. Einstein himself rejected the idea even
though his own theory demanded its "reality." Hawking (the
famous Cambrige fellow in the wheelchair) bet his friend Skip that they
didn't "exist," even though his own studies clearly told him that they
did. (He thought of it as theoretical astrophysical insurance, but
it was really superstition on his part -- which makes him, unlike most
physicists, human.)
For years, you heard the "ists" talk a lot about the possibility
that black holes might "exist" at the center of our galaxy, and maybe at
the centers of many other galaxies, too. Below one is "shown."
The Hubble took a shot of the Hubcap galaxy, and there it was. At
the center of the right hand picture, inside that white ball, is a galactic
core black hole. The bright glow comes from matter speeding towards it.
Before Hubble astrophysicists thought it might be
easer to find one in a binary (two star) system. The Mauna Kea find
mentioned at the top of this article stirred some hopes. It has to
do with measuring orbital irregularities. (Large objects going around
other large objects cause them.) This wobble can be identified by
a shift in spectral lines.
(But how one measures the wobbling of a galaxy is
beyond me. Yes, galaxies have spectral identities, and no I don't believe
even Bill Gates can come up with software that can identify the spectral
shift of a Galaxy a billion miles away that just moved four feet to the
left.)
What's a spectral identity? And, how
does this identity shift?
If you want to see a spectrum, look at a rainbow.
Imagine dark lines between the colors. Spectral line shifts, like
the famous "red shift" that is explained by an expanding cosmos, are now
nailing down planetary systems! As a planet and its star orbit around
a mathematical gravity center they make each other wiggle. The fact
that planetary orbits are elipses rather than perfect circles doesn't hurt,
here. The star wobbles more when the planet is approaching perihelion
(nearest orbital position) and less when the planet heads for aphelion
(most distant orbital position)
When the star is wiggling toward us, the spectral
lines, like the sound of an approaching train whistle, shift "up."
When the star is wiggling away from us, the spectral lines, like the sound
of a departing train whistle, shift "down."
As mentioned, only nearby companions of classical
mass can make that happen. One star out there has something going
around it every four of our days. You read that right. A planet
with a year four days long.
Astronomers think the photo below may be the first
visual of an extra-solar system.
But, even though we now know there are planets out
there, for reasons described below, we may need a black hole to get to
most of them.
It has long been believed that a black hole
may reside about 6,000 light years away in the constellation of Cygnus
the Swan, orbiting a giant star designated as HDE 226868. The astronomers
haven't seen it, since you can't. As I said, it traps light.
But there is something out there that is not only affecting the orbital
path of the star, but also stirring up a lot of X-rays.
Whatever it is, it's too big to be a planet
and too dark to be a normal star. Binary, or double, star systems
seem to be quite common in the universe, and they shift each other's spectral
lines as they go around each other. But HDE 226868's companion isn't visible.
It could be a black hole.
The x-rays fit the pattern, too. Things
captured by a gravitational field accelerate toward its center. They
bounce up against each other now and then on the way in. Compress
any gas (reduce its volume) and you get heat. Some things emit radiation
when that happens.
The book shown was written by the genius, Hawking.
Click on the title here in the text to order it from Amazon.com, then use
your back button to return. A
Brief History of Time is just one of the books I drew from in
the process of writing this text, but it is one of the best. Another
one, written decades ago by Adrian Berry is titled The Next Ten Thousand
Years. In some respects, this 1974 work is mildly out of date, now,
but I believe it to be still the finest predictive work ever on the future
of man in space.
Okay, black holes and Relativity. To understand
what this thing we can't see, and that Hawking says isn't even in our universe,
is like, we must now take a very selective course in basic post-Newtonian
physics.
Don't worry. It'll be as easy to grasp
as the aforementioned U.S. tax code.
Important point about Relativity #1: Light,
for some reason, is as fast a thing as exists. In free space, light
travels nearly 670 million miles an hour -- or, as my HAM radio friends
will tell you, 300,000 kilometers per second. Oddly enough, it maintains
this speed irrespective of the velocity of its source. Whether you
throw a ball of light forward off the front of a rocket or backwards off
the tail, it will travel at exactly the same speed. Its spectral
lines, measured by astronomers, will shift, but its MPH won't.
(I think this is ridiculous, frankly.
But scientists swear it's so.)
To say it another way (with a tip of the hat
to Arthur C. Clarke) if you, yourself, were on an escalator that was ripping
along at the speed of light, whether you stood still, ran back down or
leaped forward, you'd get to the top at the same instant from the point
of view of an imaginary (and stationary) outside observer.
(Which is more legerdemain, since according
to the same scientists, nothing anywhere is stationary.)
I'm not sure you could do that, of course.
Run up an escalator that was traveling at the speed of light, I mean.
Einstein, and the other physicists may not let you. According to
them, although you would seem a picture of health to yourself, to that
outside observer you would appear very much like Roseanne Barr: infinitly
massive and infinitely wide, with zero depth.
This happens, incidentally, anytime anything
with mass goes anywhere. It becomes wider at ninety degrees to the
direction of travel, thinner (has less depth) in the line of travel, and
grows in mass. You don't notice it in your car because the effect
doesn't get really going until you're whipping along at a serious chunk
of the speed of light.
Important point about Relativity #2: Light
"curves" in the presence of a gravitational "field." (photo shows
gravity-distorted light images due to to galaxy cluster) That was tested
during an eclipse, and also found to be true. Things that were behind
other things were visible. The light from the first things, therefore,
was bending around the second things. Which means that light must have
mass.
But you don't even need a classic, or planetary,
mass to screw things up. As our aforementioned escalator approaches
the speed of light, something very strange happens. We feel, again,
that everything is normal, but in truth our time has slowed down when compared
to that outside observer who isn't on the escalator. This scientific
peeping tom might age ten thousand, a hundred thousand, a million years
before we need our next shave! Exactly at the speed of light, time
stops completely.
This is known as UDST (Ultimate Daylight Savings
Time), and the principle has been tested. Two atomic clocks (timepieces
that count the decaying particles in Cesium atoms, which can't be an exciting
job) were used. One was put on a speeding jet, the other nailed to
the ground. The airborne clock lost time with respect to the
other one. When the plane landed, its clock was "younger" than the
ground-bound chronometer. (Had recorded less time.)
Whether this was due to the speed of the airborne
clock, which would be more massive than the clock on the ground, or due
to the distance of the airborne clock from the mass of the earth (the force
of gravity declines with distance), or both, I have no idea. Since
the same experiment worked the same way with the clocks sitting at the
bottom and top of a water tower which was not flying anywhere, it makes
one shiver. But, the clock at the top of the water tower, like the head
of a golf club, was going faster than the clock at the base, so it might
mean that the hurrieder you go, the behinder you get.
Now, back to the iron sun.
A black hole is very, very, very, very massive,
so both light and time go into orbit around one, sort of. Don't think
about this, either. Just remember that it's always happy hour in
the vicinity of a black hole. It's always 5 P.M. Checks never
get to the bank, so you're never overdrawn. No horse ever crosses
the finish llne, so you never lose, and if you go in at the age of 23,
you will always be 23.
The significant point is that the greater
the mass (amount of matter) in a given volume of space, the greater the
curvature of the light. And, similarly, the greater warping (for
the Trekkies) of what we call time. A golf ball affects light and
time a little. Our sun affects them a lot. Galactic clusters
mess them up good. A black hole controls both the horizontal and
the vertical.
Important point about Relativity #3: (from
the General Theory of Relativity) Space (the nothing between things)
exists only because the things exist. No things, no space.
And (get ready for this) it is affected by "gravity" just like light and
time!
A rational person would add all the above and come
up with the conclusion that space has mass! (The man's gone
round the bend, Martha. He just said nothing is something!)
Well, I did not say that. I don't think
Einstein said that, either. And, Stephen Hawking, who gets money
for teaching it at upscale British universities, probably didn't say it
either. What they seem to be saying is that even though space doesn't
have mass, it acts like it does. I have absolutely no idea what that
means. Anyone who does should be put on Prozac.
But, insane or not, this stuff we've been
discussing might have a use. It might open the door for extremely
long distance space travel. This is important, because all space
travel is extremely long distance.
If you wanted to walk to the moon, you'd have
to hoof the equivalent of ten times around the Earth. That's 240,000
miles or, oh, let's say nearly four hundred thousand kilometers.
To go to the Sun to get a better tan, your star trek would cover a hundred
and fifty million kilometers (93,000,000 miles).
Pluto, sometimes the eighth planet because
it has a bizarre orbit, is at times as far as seven billion kilometers
away. The nearest star is 4.3 light years. (A light year is
the distance light travels in one of our years, 9.5 million million kilometers
or nearly six trillion miles.)
Our galaxy, the Milky Way, is a hundred thousand
light years across. So, to walk from one side to the other, we would
have to cover six hundred thousand trillion miles. And, the most
distant objects we know of are (twelve to fifteen) billions of light years
distant. It's impossible to express that kind of journey in miles
because there are not enough zeros to do it.
There are two reasons why we'll go, though.
It's in our nature to poke around in new territory, of course. But,
as mentioned earlier, in a few (four or five billion) years we're going
to have to because our sun is going to expand into a Red Giant whose outer
atmosphere will include the orbit of Mars. The Earth will then be
inside the sun. Stock in air conditioning companies will shoot up
in value and Florida, having boiled away, will lose some of its winter
attraction.
But, space offers alternative off-season destinations.
Our galaxy, the Milky Way, has a hundred billion suns, and there are at
least half that many other galaxies. We already know that some other
stars have planets. Some of these planets may be uninhabitable, like
North Dakota. Others may be veritable Edens, like Washington, D.C.
No doubt there are some nice places out there.
The problem is, of course, getting there.
(Apollo 11 launch. These ships are streamlined)
(Space ships that don't operate in an atmosphere don't have to be aerodynamic.
They can look like the Gamma Ray Observatory.)
If you would care to divide fifty thousand
miles per hour into a hundred trillion miles, which would get you around
the galactic neighborhood, so to speak, you will see why some people have
suggested making giant "colony" ships. These rigs would be inside-out
worlds with a completely enclosed, recycling ecosystem.
The people who started out in these sub-light
vehicles wouldn't see the nearest star with habitable planets in their
lifetimes, but their great, great, great, great, great, great, great, great,
great, great, great grandchildren might.
A spaceship that big would have a lot of mass.
Even using the slingshot method of stealing velocity from a planetary mass
in a near flyby wouldn't do the job.
It would take a lot to get it going and a lot to
slow it down. They might have to do that for every star they passed
because of another Relativity effect. The closer you get to the speed
of light, the weirder things that aren't going as fast as you look.
So, the faster you go, the harder it is to
simply look out the windshield and see where you are.
Einstein giveth, and Einstein taketh away.
I wouldn't be surprised, however, if optics
and computers could adjust for a lot of the navigation, and even visual,
difficulties.
(Actually, if we're talking about "nearby"
stars, we're probably no more then twenty years from sending an unmanned
ship. The problem is mostly engineering, and will probably be solved
with an engine that uses hydrogen, the most commen element in the universe.
When we can come up with a one G (one earth gravity) accelleration for
a hundred days, we can get to Proxima Centauri and back in nine years or
so, ship time.)
Some fanciful folks, like Portland, Oregon's
science fiction writer and former OMNI fiction editor, Robert Sheckley,
believe faster-than-light travel will be harnessed by some kind of special
engine. Nick Herbert, in his fascinating "FASTER THAN LIGHT: Superluminal
Loopholes In Physics," points out that there is no theoretical reason why
the humps of a caterpillar can't exceed the lightspeed barrier. The
caterpillar, he points out, can't, but the humps can.
(Remember when I said "nothing can exceed
the velocity of light"?)
This is based on the reasoning that there
may be no light barrier at all for those "vehicles" which carry no "message."
No cargo, no information, in other words. Stephen Hawking, uncomfortably
aware that astrophysicists are calling weird particles that somehow seem
to escape black holes, "Hawking particles," agrees with Herbert.
This hump method, to me, does not seem a practical solution for avoiding
the future worldwide barbecue. It's even worse than the colony ship
concept.
If these "Hawking particles" or, if you prefer,
this "Hawking radiation," don't or doesn't provide some unsuspected avenue
to the stars, we have only only one possible way to travel long distances
in space, it seems.
And, that way may be via the space-time effects
of a black hole.
It goes like this. You are standing
in Astoria, Oregon near the mouth of the Columbia River, and you want to
visit a friend who lives over on the Washington side. How do you
get there if you don't have a boat and if the bridge just fell down, and
you can't swim, and you don't know anybody who owns an airplane?
Simple: you drive all the way up the river,
through Oregon, Idaho and Canada, go around the headwaters and come all
the way back down along the other side. That's normal space travel.
But, if you don't have the time for that, what you need is for somebody
to build you a bridge. That is what some people think a black hole
is: a bridge.
Well, that's enough basic astronomy for now.
Fun is fun, but we have work to do. Now that we know we'll be needing
one of these things, let's find out what it is and how it got that way.
Maybe then we can figure out how to use it.
First, a black hole was a star. Probably
even used to shine, just like our own sun. But it was bigger.
At a minimum from three to seven times bigger, at least. Ten times
is more likely. Using the less likely smaller figure, we'll put it
in nice round numbers that anybody can grasp. Since our sun has a
mass of 2,000,000,000,000,000,000,000,000,000 tons, a black hole must start
out as a star of at least 6,000,000,000,000,000,000,000,000,000 tons.
(Compare that to the Earth, which "weighs"
a puny six times ten to the twenty-seventh grams.)
Aha! you say. If it takes that size
of a thing to be a black hole, and if it was that size, then it couldn't
have ever shined like our sun. Ipso fatso. It either is or
it ain't a black hole, Leonard!
True.
But, you see, I said it had to be that big
to start with. Just because it is at least three solar masses doesn't
mean it's a black hole. There are lots of stars out there that are
a hundred, a thousand times bigger than our sun, and they shine just fine.
The thing is, every heavenly body (Julie Christie's,
for those old enough to remember "Dr. Zhivago," for example) no matter
what size has what is called an "escape velocity." How fast you have
to go to get away from it without falling back when you turn off the rockets.
You could run fast enough to get off the smallest
planetary moons in our solar system. Our astronauts have to poke
along at 25,000 mph to get away from Earth. If they were trying to
break free of Jupiter's grasp (see photo), they'd have to kick in the afterburners
and pedal like crazy, since that planet's escape velocity is more than
135,000 mph.
That escape velocity is determined by the
object's mass, of course. Jupiter's mass is greater than every other
object in our solar system combined--excluding the sun. It "weighs"
more than all the other planets, moons, comets, asteroids and 1953 Buicks
combined.
But it's not just the extra mass that matters.
The other big factor, when we're talking about black hole escape velocities,
is the radius: the distance from the center to the surface of a stellar
sphere.
The density, in other words.
(Uranus, our seventh planet, is a gas giant.
It's much larger than earth, yet has a density less than that of water.
Uranus should float, as should Neptune, shown in this photo!)
I detect glimmerings in your head.
"Let's see ... 25 grand to get away from Earth
... 135 for Jupiter ... our potential black hole shines even though it's
massive enough not to ... Eureka! Then it has to shrink -- the radius
must get smaller, the density increase, before it's a black hole!"
Congratulations. You have just won an
autographed photo of a carbon atom in a compromising position.
So, how does it happen? Somebody let
the air out?
In a manner of speaking, yes. Look,
you know that our sun (that's its surface in the photo) is a bunch of mostly
hydrogen engaged in a process known as nuclear fusion. The middle
parts of all those hydrogen atoms are jammed so tight by all that gravity
that they fuse together. Einstein's famous equation, E equals MC2
(energy equals mass times the square of the speed of light), does its number
after that and the hydrogen is transmuted (converted) into helium, plus
some leftover energy is released which makes sure that the girls of California
end up with a white mark where their deliciously brief swimsuits were.
A sun starts out as a massive hydrogen bomb
surrounded by a big hot air balloon; Sagan's gigantic glowing glob of gas.
Its size is determined by the balancing act between elastic forces, the
expanding hot gases, and gravity. When, inevitably, the fuel is exhausted,
the sun comes to a point where, unlike politicians, it runs out of gas.
There are all kinds of wonderfully complex
things that can happen, then. Multiple explosions (novas), one real
good banger (a supernova), simple expansion and contraction (variable stars),
all sorts of possibilities. In the case of a sun destined to become
a black hole, eventually the leftover lumps of non-sentient matter (iron,
1953 Buicks and liberals) form into new bigger lumps, which attract other
bigger lumps until the atomic structure (normally mostly space) collapses.
Eventually, it's hard for a lump to turn around in there, let alone Boogie.
Jam the population of Tokyo into a Honda ash
tray and you're getting there. Compress the Earth into an object
the size of a marble and you are there.
Thus, when a star burns out (transmutes its
original fuel into elements that won't sustain nuclear fusion), it can
begin to fall in upon itself. Its radius may start to diminish.
What it becomes after that depends in part
on the original mass.
It might become a white dwarf star and get
the lead in a Steven Spielberg fantasy movie. Or it might become
a pulsar; a solid carbon "radio" star. It might even go supernova
and guide the Seattle Seahawks to the Superbowl.
But, if it has enough mass to begin with,
and some other known and unknown conditions exist, it may continue collapsing
until its mass/radius ratio demands a greater escape velocity than even
light can manage. And, since there ain't nothing faster than light,
no matter what goes in, it don't come out, right?
Right, except, possibly, for Hawking particles/radiation,
whatever they/that is/are or isn't/aren't. (They could be merely
particles that appear to be coming from the collapsar.)
"So," you ask, "why are we even discussing this
thing? I can't get anywhere in drivetime traffic. How would
flying into a black hole help me get anywhere?" (When you think about
it, the two are very similar, aren't they?)
Well, it wouldn't. But what if you just
grazed one? What if you could fly by real close?
In 1963, a mathematician named Roy Kerr got
to mathematizing about these collapsars. One thought he had was really
interesting. Black holes, he postulated, like most other celestial objects,
must rotate. Figuring that out might not seem like much to you, but
it would impress Copernicus, who built a reputation on a single shtick;
and not even an original shtick, since Aristarchus of Samos suggested a
sun-centered "universe" long before the C-man did. Kerr wasn't hied
to the house-arrest slammer by the church like Copernicus, but his suggestion
set some scientific folks on their ears. To those who understood
the implications, it meant, among other things, that we might not be doomed
in four billion years, after all.
Quick scene change. We are watching
an ice skater, a lovely girl in a lovely small costume, whirling in place.
As she begins to bring her lovely outstretched arms into her lovely body
she spins faster and faster. Soon, unfortunately, she is a blur.
What caused that? (The speedier spin,
not the blur.)
The Law of the Conservation of Angular Momentum
caused that!
I bet you knew it all along.
Take an object ten times the mass of our sun,
squeeze it into a ball fewer than forty miles across and the aforementioned
law will have it spinning around a thousand times a second. At the
slow rotational rate of the Earth, there's an equatorial bulge. Imagine
the bulge at a thousand times a second!
In the case of the black hole, it may not
be a simple bulge. (Actually, the earth is slightly pear-shaped.)
Some people think it warps into two frisbees stacked back to back.
That may or may not be important. What is, is this other business,
the warping thing. Remember when we discovered that nothing (space)
is a thing that can be bent? And, remember how we avoided driving
around the Columbia River?
You see, until black holes came along,
the faster than light warp drive of the star ship Enterprise was nothing
more than a literary tool. I suppose this will be confusing, but
it still is. Nothing "substantial" can exceed the speed of light
in free space. Nothing with mass will ever equal it and remain mass,
or at least the kind of mass it was.
Anyway, in spite of all of the above -- in
spite of the Einsteinian travel restrictions from the first years of this
century -- it is now Einsteinian theory, quantacized via Max Planck, that,
via black holes, offers travel that seems faster than light. (And from
one viewpoint is, and from another isn't, neither of which is my fault).
Here's how it works. The great mass
of a black hole warps (bends, curves) space and time the way it does light.
So those things are turned back upon themselves to varying degrees in the
vicinity, like the southern bank of the Columbia River goes all the way
to Canada and bends back on itself to become the northern side.
Two locations, in one sense 2,000 miles apart
are, looking at it in another way, only 2 miles distant from each other.
If our spinning black hole does have an odd
shape, there might be an adjacent distortion in the fabric of space-time
(whatever that is)... a ripple of varying time-space conformation just
outside what is known as the hole's "event horizon." (So called because
any "event" that takes place inside it is invisible to our universe.)
A space ship, if it could skim by the event horizon -- which
it must not cross since the vehicle and occupants would be stretched into
infinitely long threads that would fall, screaming, towards the center
of gravity of the collapsar, never reaching the bottom because Max Planck
won't let it, yet instantly reaching the bottom, probably due to "spooky
action at a distance" or simultaneity, which has recently, impossibly,
been experimentally proven, depending on one's perspective -- might be
able to scoot through this ("window" some people call it) and so would
benefit from a geodesic (the shortest distance between two points) that
is a fraction of the geodesic it would traverse going to the same destination
(planet, star, galaxy) via a route farther away from the collapsar that
would utilize a path in "normal" space-time where the geodesics are, as
viewed from the perspective near the collapsar, longer.
When the ship popped out, it would be a long
way off from the entry spot, additionally placing us, the passengers,
from the perspective of those we left on Earth, ten million years in their
future or, from our perspective, placing them ten million years in our
past. .
I mean, why not? All you're talking about
is the mathematical equivalent of parallel mirror image Hawking/Gnikwah
universes which interchange Dilbert-mass for Frohmm-energy and vice versa
at an infinite number of identical but sign-opposite pointillistic cosmic
quantum-duality intersections!
(Sorry about that. If you spend too much time
with this stuff, it can damage you. Four pounds of light fall on
the earth every second. How do you like that one? Want to hear
about wavicles? Or string theory ... that the universe is an expanding
cosmic bowl of noodles? People get paid to sit around and come up
with stuff like this! Worse yet, it may be true!)
Anyway, one author claims that the double-stacked-frisbee
theory says there's a slot about six hundred feet wide that you might be
able to use. One problem most physicists have with that comes out
of their belief that anything on the "in" side would be pulled into the
black hole at a different rate than anything on the "out" side. Your
left side would wish to leave your right side, in other words. Think
of it as a split personality, in spades. So, the scientists believe
it would be painful.
But, who knows? If somebody had told
your great grandparents when they were in their twenties that before the
end of the 20th Century, we would be doing triple organ transplants in
human beings, cloning mammals and walking on the moon, they would have
laughed the idiot out of town.
I think we'll figure it out, eventually.
Martian robot vehicles and space telescopes will not, in the end, be enough.
Even before the sun turns the Earth into a charcoal briquette, we'll put
our itchy foot on a superluminal gas pedal and head out. By utilizing
brilliant scientific deduction, spectacular engineering and plenty of duct
tape, we will yet get the opportunity to spread our wonderful species throughout
this galaxy and beyond. The only problem I can forsee is the fact
that we don't have any black holes in this neck of the cosmic woods.
The nearest possibility I've run across during my research, and which I
mentioned an eternally long time ago at the top of this article, is 6,000
light years (35,400 trillion miles) away.
Which is why some people have suggested we
might just go ahead and build our own, somehow, near Los Angeles or out
past Pluto where it won't suck up anything important. It might work,
at that. Let's see, now ... one dump truck holds four 1953 Buicks,
and we need, say, to be safe, ten solar masses ... so that's four, carry
the six ...
- 30 -
Mars is uncrowded in the off season, but it's the M82 exploding galaxy on the 4th of July
* The Royal Dane, Tycho Brahe, had a metal nose, and his assistant, Johannes Kepler, who discovered that planetary orbits were elipses rather than circles, was a son of a witch.)
Photo credits go to NASA, the folks at Mt. Wilson
and the Johnson Space Flight Center.
Don't
believe what's in this article? Click here. (NASA page link)