Black holes are going to kill you and everyone you love.
Well, maybe.
As one of the most powerful forces in the universe, black holes were originally believed
to be a myth for centuries, and were only recently proven to in fact exist by modern
science.
Way back in 1687, Newton blew the mind of every scientists alive when he dropped his
famous book, Principia.
When earth's scientists were done scooping their brains back inside their skulls, they
discovered that Newton's three-volume work, Philosophiae Naturalis Principia Mathematica,
had mathematically described the laws of motion and universal gravitation.
Then a hundred years later a British monk by the name of John Michell used Newton's
own math to deduce that there might in fact be an object so massive that matter would
need an escape velocity greater than the speed of light in order to escape its gravitational
attraction- a physical impossibility.
This didn't jibe well with the scientific establishment, and in the 1900s even Einstein
joined in on the anti-black hole bandwagon.
Then in 1970 scientists discovered Cygnus X-1, which was at the time the best candidate
for a real-live black hole, and in 1994 the Hubble telescope took photos of stars orbiting
at incredible speeds near the center of their galaxies, indicating an invisible supermassive
object.
Then, following the age-old adage of “picture, or it didn't happen”, scientists managed
to photograph a black hole for the first time earlier this year.
We'd love to say that this for sure settled the debate on the existence of black holes
with even the most die hard unbelievers, but well, there's hundreds of thousands of people
around the world who still believe the world is flat.
This picture of a black hole was taken from the galaxy M87, and shows a supermassive black
hole at the heart of the galaxy with a mass of 6.5 billion of the earth's suns, and with
a diameter of 24 billion miles (38 billion kilometers).
The black hole is so big, that if you were to try to cross it by a modern jetliner...
then you would instantly be disintegrated because nothing can enter a black hole and
survive.
That's because a black hole's gravity is greater than any force known or predicted by science,
and there's simply no escape once you're caught inside it.
That includes light, which is why the photo of the black hole inside galaxy M87 is only
possible due to the superheated gas and material that is stuck around its event horizon- the
point of no return.
The intense gravity causes this material to spin so quickly that it heats to incredible
temperatures, and makes the edges of a black hole visible to X-ray detectors.
Not content to let these galactic monster lie dormant, scientists have continued to
press on in their quest to understand black holes, and one of their leading questions
was: just how fast do these monsters really spin?
The answer turned out to be, really, really fast.
Measuring the spin of five different supermassive black holes, all safely located around 10-11
billion light years away from earth, scientists discovered that the event horizon of one of
these giants was spinning at just shy of the speed of light, 670 million miles an hour
(1.1 billion kph).
Turns out that this particular black hole was an overachiever though, and the other
four black holes were only found to be spinning at about half of that rate.
One of these black holes however had a large spinning vortex of material, known as an accretion
disk, which was found to be spinning at a vomit-inducing seventy percent the speed of
light, which might just make it some of the fastest moving material in the universe.
But you can rest your fears about black holes to rest, because the truth is that, despite
popular opinion, black holes are actually pretty safe stellar phenomenon.
That's because black holes don't really 'suck in' objects, but rather have a gravitational
influence that catches wayward objects.
As long as you stay outside of its gravitational influence, you and your space ship would be
perfectly fine.
Even if you managed to get inside its gravitational field though, most matter is spun around with
so much force that it is ejected back out into space.
Only a small percentage of matter actually manages to reach the event horizon, where
its fate is doomed.
If your ship reached this point, then you're in some serious trouble.
As you approach the black hole the gravity is so intense that the gravitational force
your feet experiences is far greater than your head, and so your body would be stretched
out at the atomic level in a process scientists have termed, 'spaghettification'.
The good news is though that time itself would be warped by the intense gravity, so much
so that it would actually move at a fraction of the speed it moves for the rest of the
universe.
So as you fell inside the black hole your own personal perception of time would slow
to a crawl, and if you were to look out at the universe you would see the rest of the
universe moving along at normal speed- so as you're slowly being sucked into a black
hole you would actually be able to watch the universe evolve over billions and billions
of years.
Well, you'd be able to do this if you weren't, you know, a long string of atoms being slowly
ripped into their fundamental particles.
So just stay out of a black hole and you're safe, right?
Well, remember how at the start of this episode we told you a black hole was going to kill
you and everyone you love?
That was only half-wrong.
Most black holes are so massive that they hold the rest of the galaxy in place around
themselves, all the stars and their planets orbiting around what becomes the galactic
core.
The stars are caught in the black hole's gravity field, but due to their velocity are safely
kept in orbits that never bring them close enough to be consumed.
Therefore, relative to you and me, the black hole at the center of our own galaxy doesn't
move- it never gets any further or closer away from us unless our own orbit is highly
eccentric.
Not all black holes play by the rules though, and some black holes are galactic wanderers.
While scientists don't believe that supermassive black holes are capable of being galactic
wanderers, many smaller black holes are believed to be right now roaming space, devouring everything
they come across and totally invisible as they stalk the heavens above.
Black holes may be huge sources of gravity, but they too are affected by the gravity of
other objects- thus smaller black holes can be ejected from stable orbits by interactions
with other sources of gravity, and set them on a collision course with stars, planets,
and maybe, possibly, one day you and me.
Such an encounter would be extremely rare, and probably doesn't warrant much panic- but
some scientists have hypothesized that the earth encounters much, much smaller black
holes the width of a human hair, at a rate of about 1 per 1,000 years.
These are remnants from the Big Bang, formed in the first nanoseconds of all creation,
and whizzing through space like cosmic bullets.
While these shrimpy black holes most likely don’t exist and certainly won't be able
to destroy the earth, if one were to cross your path the incredible tidal effects on
your body might just kill you.
So don't worry, because black holes aren't going to kill you and everyone you love.
Probably.
Maybe.
How would you save the earth from a rogue black hole?
Let us know in the comments!
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