Download The following article provides a short look at another Black Hole

Grade 9 Applied Science – Space
Black Holes
http://teacher.scholastic.com/researchtools/articlearchives/space/BlackHole.htm
How does a Black Hole form?
The theory is a Black Hole forms when a very massive star collapses at the end of its lifetime.
Like our sun, stars produce energy from nuclear reactions occurring deep inside the star. In these
reactions, hydrogen is converted to helium. The chemical reaction gives off energy, which in turn,
becomes light. Once that hydrogen is used up, stars use helium for the reaction. Eventually, the star will
run out of "fuel", collapse and become a "white dwarf."
Very massive stars — 10X heavier than our sun — have such strong gravity that when they collapse they
cannot stop. Everything in the star collapses to a tiny point that still has the mass and gravity of the star
but no longer shines. The gravity is so strong that even light cannot escape, and a Black Hole is formed.
Does a Black Hole "suck" down everything in its vicinity?
The gravity of a Black Hole is the same as the gravity of a star with the same mass. If the sun suddenly
became a Black Hole, Earth would continue to orbit the Black sun as usual. The danger is that if you get
too close to the Black Hole, the gravitational pull would be extremely strong and it would be hard to
escape.
Have astronomers found any Black Holes?
Yes. Can we see a Black Hole? No, it is Black. We can see hot gases being "sucked" into the Black
Hole. The collisions and explosions that occur as the gases collide generate huge bursts of light
including X-rays.
Several stars appear to have invisible but very massive companion stars. The invisible companion
appears to pull gas from the regular star.
We also see explosions in the centres of some galaxies.
How do Black Holes have energy if they form from dead or burned-out stars?
Black Holes form from large stars that collapse when they run out of fuel for their nuclear reactions.
There are many forms of energy — heat, light, energy of motion and the energy of gravity. Black Holes
have LOTS of gravitational energy.
Are there any Black Holes in our galaxy?
There are no Black Holes near our solar system, but there are several Black Holes in our galaxy.
We think that galaxies have a big Black Hole at each centre. Our Milky Way probably has a big Black
Hole at its centre, but it is hard to tell because there are so many stars in the way when we look toward
the centre. (NOTE: The centre is in the constellation Sagittarius which you can see during the summer
towards the south).
Could a beam of light orbit a Black Hole?
It is possible if the light came in at just the right angle so it would be in a perfectly circular orbit. It is more
likely the light would either pass by the Black Hole in a curved path or go into the Black Hole.
What is meant by the term associated with Black Holes called the "event horizon"?
A beam of light is passing by a Black Hole. The gravity of the Black Hole pulls on the light, but the beam
of light has energy that offsets the pull. The Black Hole’s gravity bends the light beam, but if the light is
not too close, it can pass by the Black Hole. If the light gets too close, the gravity of the Black Hole bends
the light into the Hole. Thus, there is a sphere around the Black Hole where, if light (or an object) went
in, it could not come out. The sphere is the "event horizon."
What is at the end of a Black Hole?
In science fiction, people travel through Black Holes. Some people have suggested that you could go into
one Black Hole and come out another. That is science fiction. At this time, there is no answer.
Could a probe be sent down a Black Hole and send information back?
There are two problems.
1. We do not have, at present, the technology to explore that distance in space. The nearest Black
Hole is many light-years away. With current technology, it would take thousands of years for a
probe to reach the nearest Black Hole.
2. Radio waves are a form of light. Light cannot escape from the Black Hole because of the huge
gravity. At present, we could not get information out.
What happens to time in a Black Hole?
Time is no different inside a Black Hole.
Will the sun become a Black Hole?
Our Sun will never become a Black Hole. Only a very big star, several times more massive than our Sun,
will become a Black Hole.
How close can something get to a Black Hole before it is sucked in?
That depends on how much matter has been pulled into the Black Hole. The more matter, the stronger
the gravity.
If a Black Hole were inside a cloud of gas, the gas near it would probably be pulled in. Now, the Hole has
more matter, and thus, it has more gravity. More mass, more gravity.
What are white Holes?
A "White Hole" is supposed to be the opposite of a Black Hole. If matter and light can be trapped inside a
Black Hole, then a White Hole is where the matter and light come spewing out.
What is a Wormhole?
An idea that two Black Holes could be connected. This is a Wormhole. How would you know? Could
you escape the gravitational pull of the second Hole to know it is a second hole?
SUMMARY
A Black Hole is a region where matter collapses to infinite density, and where, as a result, the curvature
of space-time is extreme. As well, the intense gravitational field of the Black Hole prevents any light or
other electromagnetic radiation from escaping. To summarize, a Black Hole is a region where matter
and energy disappear from the visible universe?
A Black Hole grows by pulling in the mass (…and the associated gravitational energy…) around it.
Theoretically, a Black Hole can emit particles. A big Black Hole would emit a particle very slowly;
whereas, a small hole would have explosions.
Black Holes
Answer the following questions applying your acquired knowledge and ideas.
Question
Your Idea
What is a Black Hole?
How does a Black Hole
form?
Why would a Black Hole
suck things into it?
Will everything be sucked
into a Black Hole?
Can we see a Black Hole?
Why? Why not?
How could you tell a Black
Hole exists?
Where does a Black Hole
get its energy?
What is meant by the term
“Event Horizon”?
How close can you get to
a Black Hole without being
sucked in?
Could we get information
about the inside of a Black
Hole by sending a space
probe into one?
Will our Sun become a
Black Hole?
If our Sun did become a
Black Hole, what would
happen to Earth?
What is a White Hole?
What is a Wormhole?
Class Idea
Black Holes
The following article provides a short look at another Black Hole theory. Read the article and, in your own
words,
 Highlight the main points
 Provide your opinion (e.g., Are Wormholes possible?)
Adapted from: Than, Ker. 9 April 2010. Every Black Hole Contains Another Universe? National
Geographic News. (Online). http://news.nationalgeographic.com/news/2010/04/100409-blackholes-alternate-universe-multiverse-einstein-wormholes/
Like part of a cosmic Russian doll, our Universe may be nested inside a Black Hole that is itself part of a
larger universe. In turn, all the Black Holes found so far in our universe -- from the microscopic to the
supermassive -- may be doorways into alternate realities.
According to a mind-bending new theory, a Black Hole is actually a tunnel between universes -- a type of
Wormhole. The matter the Black Hole attracts does not collapse into a single point, as has been
predicted. Rather, it gushes out a Hhite Hole at the other end of the black one.
In a recent paper published in the journal Physics Letters B, Indiana University physicist Nikodem
Poplawski presents new mathematical models of the spiraling motion of matter falling into a Black Hole.
His equations suggest such wormholes are viable alternatives to the "space-time singularities" that Albert
Einstein predicted to be at the centres of Black Holes.
According to Einstein's equations for general relativity, singularities are created whenever matter in a
given region gets too dense, as would happen at the ultradense heart of a black hole. Einstein's theory
suggests singularities take up no space, are infinitely dense, and are infinitely hot -- a concept supported
by numerous lines of indirect evidence but still so outlandish that many scientists find it hard to accept.
If Poplawski is correct, they may no longer have to.
According to the new equations, the matter Black Holes absorb and seemingly destroy is actually
expelled and becomes the building blocks for galaxies, stars, and planets in another reality.
Wormholes Solve Big Bang Mystery?
The notion of Black Holes as Wormholes could explain certain mysteries in modern cosmology. For
example, the Big Bang Theory says the Universe started as a singularity. Yet, scientists have no
satisfying explanation for how such a singularity might have formed in the first place. If our Universe was
birthed by a white hole instead of a singularity, it would solve the problem of Black Hole singularities and
also the Big Bang singularity. Wormholes might also explain gamma ray bursts, the second most
powerful explosions in the universe after the big bang. Gamma ray bursts occur at the fringes of the
known universe. They appear to be associated with supernovae, or star explosions, in faraway galaxies,
but their exact sources are a mystery.
Poplawski proposes that the bursts may be discharges of matter from alternate universes. The matter, he
says, might be escaping into our Universe through supermassive Black Holes – Wormholes -- at the
hearts of those galaxies. However, it is not clear how that would be possible.
There is at least one way to test Poplawski's theory: Some of our Universe's Black Holes rotate, and if
our Universe was born inside a similarly revolving Black Hole, our Universe should have inherited the
parent object's rotation. If future experiments reveal that our Universe appears to rotate in a preferred
direction, it would be indirect evidence supporting the Wormhole theory.
Are Wormholes "Exotic Matter" Makers?
The Wormhole theory may also help explain why certain features of our Universe deviate from what
theory predicts. Based on the standard model of physics, the curvature of the universe should have
increased after the Big Bang over time so that now -- 13.7 billion years later -- we should seem to be
sitting on the surface of a closed, spherical universe. Yet, observations show the universe appears flat in
all directions. Moreover, data on light from the very early Universe show that everything just after the Big
Bang was a fairly uniform temperature. This means that the farthest objects we see on opposite horizons
of the Universe were once close enough to interact and come to equilibrium, like molecules of gas in a
sealed chamber. Once again, observations do not match predictions because the objects farthest from
each other in the known Universe are so far apart that the time it would take to travel between them at the
speed of light exceeds the age of the Universe.
To explain the discrepancies, astronomers devised the concept of inflation. Inflation states that shortly
after the Universe was created, it experienced a rapid growth spurt during which space itself expanded at
faster-than-light speeds. The expansion stretched the Universe from a size smaller than an atom to
astronomical proportions in a fraction of a second. Thus, the Universe appears flat since the sphere we
are sitting on is extremely large from our viewpoint -- just as the sphere of Earth seems flat to someone
standing in a field.
Inflation also explains how objects so far away from each other might have once been close enough to
interact. However assuming inflation is real, astronomers have always been at pains to explain what
caused it. That is where the new Wormhole theory comes in. According to Poplawski, some theories of
inflation say the event was caused by "exotic matter," a theoretical substance that differs from normal
matter, in part because it is repelled rather than attracted by gravity. Poplawski thinks such exotic matter
might have been created when some of the first massive stars collapsed and became Wormholes. "There
may be some relationship between the exotic matter that forms Wormholes and the exotic matter that
triggered inflation," he suggests.
Wormhole Equations an "Actual Solution"
The new model is not the first to propose that other Universes exist inside Black Holes. Damien Easson,
a theoretical physicist at Arizona State University, has made the speculation in previous studies. "What is
new here is an actual Wormhole solution in general relativity that acts as the passage from the exterior
Black Hole to the new interior universe. We just speculated that such a solution could exist, but Poplawski
has found an actual solution," said Easson.
Future work in quantum gravity -- the study of gravity at the subatomic level-- could refine the equations
and potentially support or disprove Poplawski's theory.
Wormhole Theory No Breakthrough
Overall, the Wormhole theory is interesting, but not a breakthrough in explaining the origins of our
Universe. By saying our Universe was created by a gush of matter from a parent universe, the theory
simply shifts the original creation event into an alternate reality. In other words, it does not explain how
the parent universe came to be or why it has the properties it has -- properties our Universe presumably
inherited. Yet, the idea of Universe-bridging Wormholes any stranger than the idea of Black Hole
singularities. "Everything people ask in this business is pretty weird. You can't say the less weird idea is
going to win, because that's not the way it's been, by any means," suggests University of California
physicist Andreas Albrecht.