10 Amazing Facts About Black Holes

An artists illustration of the central engine of a Quasar. These Quasi-stellar Objects QSOs are

now recognized as the super massive black holes at the center of emerging galaxies in the early

Universe. (Photo Credit: NASA)

Imagine matter packed so densely that nothing can escape. Not a moon, not a planet and not even

light. Thats what black holes are a spot where gravitys pull is huge, ending up being

dangerous for anything that accidentally strays by.

But how did black holes come to be, and why are they important? Below we have 10 facts about

black holes just a few tidbits about these fascinating objects.

Fact 1: You cant directly see a black hole.

Because a black hole is indeed black no light can escape from it its impossible for us to

sense the hole directly through our instruments, no matter what kind of electromagnetic radiation

you use (light, X-rays, whatever.) The key is to look at the holes effects on the nearby

environment, points out NASA. Say a star happens to get too close to the black hole, for

example. The black hole naturally pulls on the star and rips it to shreds. When the matter from

the star begins to bleed toward the black hole, it gets faster, gets hotter and glows brightly in X-

rays.

Fact 2: Look out! Our Milky Way likely has a black hole.

A natural next question is given how dangerous a black hole is, is Earth in any imminent danger

of getting swallowed? The answer is no, astronomers say, although there is probably a huge

supermassive black hole lurking in the middle of our galaxy. Luckily, were nowhere near this

monster we are about two-thirds of the way out from the center, relative to the rest of our

galaxy but we can certainly observe its effects from afar. For example: the European Space

Agency says its four million times more massive than our Sun, and that its surrounded by

surprisingly hot gas.

Sagittarius A in infrared (red and yellow, from the Hubble Space Telescope) and X-ray (blue,

from the Chandra space telescope). Credit: X-ray: NASA/UMass/D.Wang et al., IR:

NASA/STScI

Fact 3: Dying stars create stellar black holes.

Say you have a star thats about 20 times more massive than the Sun. Our Sun is going to end its

life quietly; when its nuclear fuel burns out, itll slowly fade into a white dwarf. Thats not the

case for far more massive stars. When those monsters run out of fuel, gravity will overwhelm the

natural pressure the star maintains to keep its shape stable. When the pressure from nuclear

reactions collapses, according to the Space Telescope Science Institute, gravity violently

overwhelms and collapses the core and other layers are flung into space. This is called a

supernova. The remaining core collapses into a singularity a spot of infinite density and

almost no volume. Thats another name for a black hole.

Fact 4: Black holes come in a range of sizes.

There are at least three types of black holes, NASA says, ranging from relative squeakers to

those that dominate a galaxys center. Primordial black holes are the smallest kinds, and range in

size from one atoms size to a mountains mass. Stellar black holes, the most common type, are

up to 20 times more massive than our own Sun and are likely sprinkled in the dozens within the

Milky Way. And then there are the gargantuan ones in the centers of galaxies, called

supermassive black holes. Theyre each more than one million times more massive than the

Sun. How these beasts formed is still being examined.

A binary black hole system, viewed from above. Image Credit: Bohn et al. (see

http://arxiv.org/abs/1410.7775)

Fact 5: Weird time stuff happens around black holes.

This is best illustrated by one person (call them Unlucky) falling into a black hole while another

person (call them Lucky) watches. From Luckys perspective, Unluckys time clock appears to

be ticking slower and slower. This is in accordance with Einsteins theory of general relativity,

which (simply put) says that time is affected by how fast you go, when youre at extreme speeds

close to light. The black hole warps time and space so much that Unluckys time appears to be

running slower. From Unluckys perspective, however, their clock is running normally and

Luckys is running fast.

Fact 6: The first black hole wasnt discovered until X-ray astronomy was used.

Cygnus X-1 was first found during balloon flights in the 1960s, but wasnt identified as a black

hole for about another decade. According to NASA, the black hole is 10 times more massive to

the Sun. Nearby is a blue supergiant star that is about 20 times more massive than the Sun, which

is bleeding due to the black hole and creating X-ray emissions.

Illustration of Cygnus X-1, another stellar-mass black hole located 6070 ly away.

(NASA/CXC/M.Weiss)

Fact 7: The nearest black hole is likely not 1,600 light-years away.

An erroneous measurement of V4641 Sagitarii led to a slew of news reports a few years back

saying that the nearest black hole to Earth is astoundingly close, just 1,600 light-years away. Not

close enough to be considered dangerous, but way closer than thought. Further research,

however, shows that the black hole is likely further away than that. Looking at the rotation of its

companion star, among other factors, yielded a 2014 result of more than 20,000 light years.

Fact 8: We arent sure if wormholes exist.

A popular science-fiction topic concerns what happens if somebody falls into a black hole. Some

people believe these objects are a sort of wormhole to other parts of the Universe, making faster-

than-light travel possible. But as this Smithsonian Magazine article points out, anything is

possible since we still have a lot to figure out about physics. Since we do not yet have a theory

that reliably unifies general relativity with quantum mechanics, we do not know of the entire zoo

of possible spacetime structures that could accommodate wormholes, said Abi Loeb, who is

with the Harvard-Smithsonian Center for Astrophysics.

Diagram of a wormhole, or theoretical shortcut path between two locations in the universe.

Credit: Wikipedia

Fact 9: Black holes are only dangerous if you get too close.

Like creatures behind a cage, its okay to observe a black hole if you stay away from its event

horizon think of it like the gravitational field of a planet. This zone is the point of no return,

when youre too close for any hope of rescue. But you can safely observe the black hole from

outside of this arena. By extension, this means its likely impossible for a black hole to swallow

up everything in the Universe (barring some sort of major revision to physics or understanding of

our Cosmos, of course.)

Fact 10: Black holes are used all the time in science fiction.

There are so many films and movies using black holes, for example, that its impossible to list

them all. Interstellars journeys through the universe includes a close-up look at a black hole.

Event Horizon explores the phenomenon of artificial black holes something that is also

discussed in the Star Trek universe. Black holes are also talked about in Battlestar: Galactica,

Stargate: SG1 and many, many other space shows.

Here on Universe Today we have a great article about a practical use for black holes: as

spacecraft engines. No one can get to a black hole without space travel. Astronomy Cast offers a

good episode about interstellar travel.

About Elizabeth Howell

Elizabeth Howell is the senior writer at Universe Today. She also works for Space.com, Space

Exploration Network, the NASA Lunar Science Institute, NASA Astrobiology Magazine and

LiveScience, among others. Career highlights include watching three shuttle launches, and going

on a two-week simulated Mars expedition in rural Utah. You can follow her on Twitter

@howellspace or contact her at her website.

Related

Could a Black Hole Fit in Your Computer or In Your Pocket?

In "Black Holes"

Schwarzschild Radius

In "Astronomy"

How Much of the Universe is Black Holes?

In "Guide to Space"

@http://www.twitter.com/howellspace

Comments on this entry are closed.

killswitch January 22, 2015, 2:00 PM

This article is cool .. but black holes do not exist

Relying on mathematical equations and computer simulation about something you cant

see ( especially in the case of dark matter ) is nonesense

Link

o TedH January 22, 2015, 5:23 PM

Ok then but what happens at the center of the Milky Way? Why do the stars

there have that velocity? What,if not a BH, makes them turn on a dime? Just

because some people dont like the data / the idea doesnt make them go away.

We should accept by now that the universe is not only stranger as we think its

stranger than we can imagine.

Link

o TonyTrenton January 23, 2015, 4:18 AM

Maybe Black holes are ruptures in the Event Horizon and bleed energy out of our

system into a region I call the Big Nothing. A region of near total entropy ?

Creating bubble Universes.A cycle of Black Hole Singularities to Black Hole

Singularities. Add infinitum .

Traveling between parallel Universes. Through Worm Holes. Would mean

crossing E.Hs and because E.Hs would be moving in respect of one another.

Navigation would be a bitch.

It appears, everything in our Universe is scalable. What we perceive depends

upon the point of view.

Link

killswitch January 24, 2015, 7:29 AM

For god sake TedH and Tony , even Stephen Hawking is giving up the

black hole heresy . Why would you need mathematical mambo jumbo that

cannot be directly proven right or wrong ! Einstien abomination of the

case of infinite ratio is stupid even Mishio Caku states that it is an

abomination ! not to mention you cannot divide by zero duh we learned

that in elementary , check wikepedia . Science has gotten why to far into

the craziness (empty space , infinite universe , diving by zero , and

computer simulation instead of direct laboratory testing ) Please i urge you

to read about the electrical universe that is proper science ..

Link

TedH January 24, 2015, 6:39 PM

Killswitch, you are right up to the Event Horizon! But beyond

that threshold our laws of common physics break down, there

are other rules governing that space. Since we can get no data

out of that region to create some new laws especially for that

region its all hypothetic. And the big names you mentioned

some hundreds of years ago big names (kings, popes, greek

mathmaticians) thought the earth was flat. When Ive learned

one thing its this: dont take anything for granted because some

famous leader / physicist / thinker said so! Relax and wait.

Link

o jette February 2, 2015, 10:14 AM

Actually that is not a proven fact any more. Stephen Hawking says that black

holes radiate information and so proves that blackholes still exist.

Link

Pvt.Pantzov January 22, 2015, 10:57 PM

i heard that they are remaking disneys the black hole. does anyone remember that

movie? if i remember correctly, the ship itself was named cygnus. the movie came out

in the late 70s, and must surely have been one of the first black hole movies. the remake

will probably be 100% action and 0% science (like the new star treks).

i imagine that the remake will be garbage like many sci-fi remakes turn out to be.

Link

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