Astronomy

PROFICIENCY: BLACK HOLES

Far off in the universe, on the grave of a star, a great monster lies in wait. It’s incredibly strong to the point where even light can’t escape its grasp. It consumes anything and everything that gets too close and nothing it gets a hold of can ever escape. This monster is a black hole. Black holes are the strongest things in the universe, and one of the most mysterious; almost everything we know about them is theory. The fact that they can be very hard to find only adds to this lack of knowledge, but astronomers are finding more and more black hole candidates and adding to the world’s knowledge of black holes all the time. No matter how many of them we find, though, we may never know more than theories when it comes to what lies within black holes.

A black hole is a region in space that has so much mas within it that the resulting gravity is strong enough to distort space-time and suck in light. The gravity of a black hole can do this because it has a high escape velocity, which is the speed an object must go to overcome the force of gravity. The earth’s escape velocity is 25,000 miles per hour, so if a person were to throw an object straight up at that speed, the object could overcome the Earth’s gravity and fly away in space. The escape velocity of a celestial body depends on both its mass and the distance to its center. The closer to the center of a planet one is, and more mass that planet has, the greater the escape velocity will be. Black holes are massive enough to distort space time, but not very big, so as a result, the escape velocity of a black hole is faster than light. Since there exists nothing that is faster than light, there exists nothing that can escape the gravity of a black hole. However, the gravity of a black hole only becomes this powerful once an object has passed a certain point call the event horizon. The event horizon is the point of no return; one you have passed it you can’t go back. From far away, the event horizon seems to be a spherical surface around the black hole that is static and unmoving, but is revealed to actually be moving outward at the speed of light when viewed from close up. This is why it’s possible to pass through the event horizon from the outside but not the inside; if the event horizon is moving outward at the speed of light, an object would have to travel faster than the speed of light to catch up to and pass back through it. This is also why it’s impossible to see anything that has gone past the event horizon, since the light reflected off of the object within the horizon would be traveling at the same speed the event horizon is traveling outward, and to go past the event horizon would require the light to move faster than light, which cannot be done. This is the reason black holes are black. If light can’t escape the black hole, then there is nothing to be reflected off of it for our eyes to register and, because no light means no color, black holes appear black to us as black. This blackness against the blackness of space makes the black hole near invisible.

It’s this invisibility that makes black holes infinitely more difficult to find than even some of the most distant stars. This doesn’t mean it’s impossible, though. Astronomers can find some of the invisible patches of extreme gravity that are black holes by observing their affect on the stars and gases nearby. Because of these influences, probably the easiest black holes to find are the ones that used to be one of the stars in a binary system. Binary systems are two objects in space that are so close together they rotate around a common center of mass, which can be within one of the objects in the case of binary stars, due to their gravitational interactions. Because the two stars in a binary system are so close, if one were to become a black hole, the normal star would be close enough that the gravity of the black hole would rip gases out of the star and form them into a ring around the black hole, called an accretion disc, which the black hole would slowly suck in. While the gasses in the accretion disc are spinning, the high speeds at which it spins would cause it to heat up to millions of degrees; hot enough to give of x-rays. If Astronomers find an x-ray source in space, there’s a good chance that it’s a black hole, especially if the x-ray source is in a binary system. Another way in which astronomers can detect black holes through their affects on the area around them is by measuring the velocity of the objects disk are orbiting the black hole, they’re heated up to several million degrees; hot enough to cause radiation in the X-ray part of the electromagnetic spectrum. This means that if astronomers detect an X-ray source out in space, they can  This means that whenever astronomers detect X-ray sources in space, they can theorize that it may be the accretion disc around a black hole, especially if the source is a binary system. Another way in which astronomers can find possible black holes through their affect on surrounding objects is by using this affect to measure the amount of mass in an area. If a region of space has been found that may be a black hole, the speed at which surrounding objects orbit that region can tell astronomers how much mass is in that region. For an object in space to orbit a mass at a given speed, the mass that it’s orbiting must be of a certain mass, and the more mass there is, the faster objects will orbit around it. This means objects orbiting at extremely high speeds must be orbiting something extremely massive.The astrophysicist Chandrasekhar proved that there exists a mass which cannot be exceeded by a non-rotating body without gravitational collapse, so if the region has a mass beyond that limit, then it can be said with confidence that that region is a black hole. It was through a combination of these methods that the first black holes were discovered and the theory of black holes was proven true.

Though black holes have been proven to be real, it doesn’t mean that there aren’t still theories relating to them. Just because we know something exists, doesn’t mean we know everything about it. For instance, the only forms of black holes to be proven are stellar black holes, formed from a single  massive star, and super massive black holes. However, there are theories of a third kind of black hole. It has been discovered that there is ‘missing mass’ within the universe; there is less mass present than scientist’s calculations say there should be and no one knows why. One of the better known proposed solutions to this phenomena is dark matter, an unseen, dense form of matter that has gone undetected until now. But this theory does not agree with every scientist, so as a result, some cosmologists prefer the theory of mini black holes, which states that countless numbers of microscopic black holes were created during the big bang and may account for some of the missing mass in the universe, because it keeps their preferred hypothesis of cosmological evolution more consistent that the theory of dark matter. Some scientists believe that if there ever were mini black holes in the universe they would have evaporated by now due to the principles of hawking radiation, a radiation black holes give out that slowly decreases mass and raises the temperature of black hole relative to it’s mass. This means that the smaller the black hole, the more it heats up and the faster it evaporates. A spinning black hole doesn’t give of hawking radiation, though, so the theory of mini black holes stands. There is another theory of another, more unlikely type of black hole called a white hole. White holes are the very opposite of black holes, as black holes suck in matter indefinitely while white holes spit out matter indefinitely. There are other theories that branch off of this one, such as the theory the matter spit out by a white hole is matter that was sucked into a black hole and carried to the white hole be means of a worm hole connecting the two. The theory also implies that the white hole connected to the black hole could even be in a different universe and the worm hole with a black hole could one day be utilized to travel to other universe. If we can find a way to , you know, not get torn apart and crushed by the black hole first. However, these theories can not be proven or even tested until evidence of the existence of white holes has been found. Besides these theories on new kinds of black holes, there are theories regarding the behavior of black holes, like the theory that they attack stars, consuming them from the inside out and maybe producing the gamma-ray bursts whose origins are unknown. Basically, the black hole invades a nearby star and sucks the star inside it from within the star itself. When the matter falls into the black hole, it can generate magnetic forces withing the black hole, causing the matter to spin so fast that the force generated by the spinning matter weakens the black hole gravity at it’s ‘poles’ enough for gamma rays to escape for a short amount of time.

There are also many other theories about the behavior of black holes, like how the super massive black holes at a galaxy’s heart reacts when two galaxies with black hole merge, as well as theories that try to explain black holes better than they currently are, such as String Theory, which is way too hard to explain along with most of other such theories. But out all the theories about black holes, there are more theories about what lies within the black holes than anything else. All that is known for sure is that at the very center of the black hole lies the singularity, a point of no volume where mass is infinite. When an object gets near enough to the black hole, it is well known that the gravity will stretch it out until it is rip apart down to particles, unless the black hole in question is super massive, in which case it will enter the black hole and be crush before being ripped apart. What is completely unknown is what happens when the object, or the objects particles really, reaches the singularity. It’s not as simple as the particles just collect there, and there is a theory that explains why. What happens is space and time supposedly switch roles inside a black hole, meaning time has space like qualities and space has time like qualities. It could technically be said that inside a black hole, time is infinite and unbound and space can only move forward into the future. (this would also mean that the more one would struggle to escape falling into the singularity, the closer they would bring themselves to the singularity, since every move they made would send them further into the future, and thus, the singularity.) So if the laws of time now apply to space, then the object inside the black hole would have to move forward into the future, which is now the singularity, forever. But what happens when the object reaches the singularity? It can not stop, go backwards, turn away from, or circle the singularity because time can only go unwaveringly forward. Some people think that the object would simply be crushed into non-existence, or forever if this proves impossible. Another theory that is more widely accepted says that the singularity is where the wormhole which supposedly connects the black hole to a white hole is located, or may even be the singularity, though this theory is as unlikely as theoretical white holes. So, sorry, no universal travel...or is there? Stephen Hawking’s baby universe theory does indeed include universal travel, but not in the same sense. When an object falls into a black hole and is ripped into particles, those particle come into contact with the singularity and simply cease to exist in real time. The singularity is the end of history, so the particles’ histories end when they come into contact with it, but this is only in real time. In imaginary time, the histories of the particles haven’t stopped, but transferred to a ‘baby universe’ along with the rest of the matter that was sucked in by the black hole. Once the black hole evaporates, the baby universe could rejoin ours in the form of another black hole of the same mass as the first, and the matter that was inside would be emitted as particles from the new black hole. In my opinion, this baby universe theory is the most probable black hole theory I have heard of yet. This is because it it not only explains where the particles go when they reach the singularity, but why the objects the matter that was sucked into the black hole doesn’t just fall out when the black hole evaporates. And this theory doesn’t just explain what happens to matter inside a black hole; this theory also offers a solution to the phenomena of the acceleration and deceleration of the rate at which the universe is expanding that has lead to the theory of dark energy, of which very little is known.

Though it is far less probable than Hawking’s theory (And with much less evidence to back it up), I have my own theory of what’s inside a black hole. It drops the idea of a singularity and of the space-time switch and assumes the inside of a black hole is larger than the outside due to the warping of space time. My theory is that the inside of a black hole is actually a small universe made up of all the matter that has been sucked inside, and that all universes are created this way. This would go with the big bang theory, which states that the universe started off as a singularity, like the singularities at the centers of black holes. The universe would have expanded from the singularity as the black hole got a hold on some matter and reduced it to basic particles such as quarks before consuming it and, thus, adding it to the universe as quark soup. Quark soup is possible in this black hole, as it has extreme density, which means it may have the right conditions for there to be extreme heat, both of which being conditions in which quark soup forms. The quark soup would have formed protons, which would have come together as nuclei, which would have compiled into hydrogen and helium, the first elements present in the universe according to the big bang. The universe would have continued expanding as the black hole consumed matter and the amount of matter that crosses the event horizon and is consumed by the black hole at a time is not consistent, meaning the rate at which the universe expanded would not be consistent. This means the rate at which the universe inside the black hole expended would be constantly accelerating and decelerating accord to the amount of matter available to the black hole and would explain the strange acceleration that has occurred in the rate at which our universe is expanding if our universe is indeed inside a black hole. The black hole would also appear the same as they are described now because this universe within the black hole is incredibly compact like the black hole. This is also how the black hole would retain the features that make it a black hole; it is still incredibly dense since it has an entire universe crammed within it so it’s gravity still reduces matter to quarks before consuming it and adding to the universe within. However, if, by some miracle, my theory actually did work, it would only be able to work this way if the black hole were stellar sized, because super massive black holes do not reduce matter to quarks before consuming it. 

Black holes mysteries wrapped in enigmas with pure, unmatched strength to top it off. For every fact we know about black holes, we have more questions, more theories, and more mysteries. Though we know how and where to find black holes, how they’re made and how they work, we can use them to prove and disprove theories and ideas, but we may never know what lies within them or completely understand their affect on space time. The future may hold a multitude of breakthroughs with black holes--travel between universes, a better understanding of our universe and how it works, a potential energy source, and more. The future is full of possibilities for these monstrous gravitational traps of space! And we can only move into the future can’t we?

"BLACK HOLES by Ted Bunn." Berkeley Cosmlogy Group. N.p., n.d. Web. 17 Jan. 2011.

Hence, no information can travel faster than the speed of light., suggesting that the object was only a few kilometers wide. Thus evidence was found that one of the stars was a compact object. Finally, found that it was greater than the critical mass, and so that it was most likely a black hole. That is about the discovery of the first black hole in our universe.. "Curious About Astronomy: How are black holes discovered?." Curious About Astronomy? Ask an Astronomer. N.p., n.d. Web. 19 Jan. 2011.

Smith, Dr Richard. "Black Holes: The Ultimate Abyss." ABC.net.au. N.p., n.d. Web. 20 Jan. 2011.

Charap, John M.. Explaining the universe: the new age of physics. Princeton, N.J.: Princeton University Press, 2002. Print

Hawking, S. W.. Black holes and baby universes and other essays . New York, N.Y.: Bantam Books, 1993. Print

"Big Bang Theory." Big Bang Theory. N.p., n.d. Web. 21 Jan. 2011.

Thompson, Alex. "The Big Bang Theory - by Alex Thompson - Helium." Helium - Where Knowledge Rules. N.p., n.d. Web. 21 Jan. 2011.

"Quark–gluon plasma - Wikipedia, the free encyclopedia." Wikipedia, the free encyclopedia. N.p., n.d. Web. 21 Jan. 2011.

"Structure of a matter, protons, neutrons, quarks, electrons, gluons: Etacude.com." General information on science: chemistry, physics, astronomy, etc from Science Park of Etacude.com. N.p., n.d. Web. 21 Jan. 2011.

"Flickr: Discussing Is a Black Hole hot or cold? in Quantum Physics." Welcome to Flickr - Photo Sharing. N.p., n.d. Web. 21 Jan. 2011.

now, the energy of the black hole (through the hole's gravity): the. " Frequently Asked Questions About Black Holes." Virginia Tech Department of Physics. N.p., n.d. Web. 21 Jan. 2011. 

PROFICIENCY: DARK MATTER AND DARK ENERGY

A person stands under a single light bulb in and otherwise completely dark void. All they can see in the vast space around them is the small area illuminated by the light bulb and anything that happens to come into the light from the darkness beyond. This is a somewhat accurate example of how much we realized we know about the universe when the mysterious forces called dark matter and dark energy were discovered. Together, dark matter and dark energy make up most of the universe, but we probably know less about them than anything other known thing in the universe.

Dark matter and dark energy are probably best described as possible solutions to two separate instances of gravitational phenomena. They aren’t the same thing; they have different properties and affects on the universe and each is applied to only one of the two phenomena mentioned before. Dark matter is meant to explain an abnormality between the gravitational mass and the luminous mass of galaxies. Gravitational mass is the the measure of how powerful an object’s gravity is and is found by measuring the speed and radius of it’s satellites’ orbits, while luminous mass is the amount of light a group of stars produces converted to a mass through a process based on what we know about how stars shine. When the two masses were compared, the amounts didn’t add up, the amount of mass exceeding what would result in the amount of  light that was given off. There’s also the mystery of the mass distribution in the outer ring of galaxies. Studies have shown that instead of the center of galaxies spinning faster than the outer edges, the outer edges somehow spin faster than the centers, which shouldn't happen because the centers should have more mass than the outer edges because the centers of galaxies have more stars closer together. No one knows how these phenomena could be explained, but one theory is that the outer edges of galaxies contains an extremely high amount of very dense, invisible, or at least very dark, matter that gives off no light and interacts with normal matter weakly. Dark matter would also explain how galaxies in clusters orbit faster than their individual masses should cause them to; if the cluster had a dark matter core, the extra mass would provide extra gravity and allow for the speed at which the galaxies orbit. There is a particle that has been recently discovered, called a sterile neutrino, that may in fact be the elusive dark matter causing these anomalies. But right now, most of what we know for sure is what dark matter isn’t, rather than what it is. We know that dark matter doesn’t come in the form of stars and planets we can see because of the luminous-to-gravitational mass ratio mismatch that brought this phenomenon into view in the first place. We know that dark matter isn’t normal matter because if it were, it would have to be in the form of dark baryonic clouds, which weren’t detected in the areas where dark matter is supposed to be, or antimatter that produces gamma radiation, also not detected. We know dark matter isn’t really just the affects of large black holes because there isn’t enough gravitational lensing. This means dark matter is a different kind of matter than normal matter, and since measurements like the mass-to-luminosity ratio tell us that normal matter can only account for 20% of the universe’s mass, the other 80% must be from dark matter. Dark matter also makes up more of the mass-energy in the universe than normal matter, 25% dark matter as compared to the 5% normal matter, and dark Energy makes up more than both of them combined, 70%.

Which brings us to what dark energy is; one of the proposed solutions to why the rate at which the universe expanding is accelerating rather than decelerating. It the 1990s, everyone thought the gravity caused by all the matter in the universe would pull on it enough to cause its expansion to slow, but in 1998, observation the Hubble telescope made of supernovae from a long time ago showed that the universe was actually expanding faster than it was during the time of the supernovae. Further research showed that the expansion of the universe did not speed up until 5 billion years ago for unknown reasons. This acceleration can not be explained by existing theories or already known forms of matter and energy, so the only explanations astronomers have is that either some of the existing theories explaining gravity are wrong, Einstein’s discarded cosmological constant is actually correct, or there’s another unknown matter or energy-fluid that fills space and exerts negative pressure that causes space time to repel itself. There are some theories that branch off of this last explanation that try to explain what this new energy is and what it’s source might be. One notion is that even in regions of space empty of all matter and radiation, the sources of all known energy, there is a residual energy from the big bang that pushes the universe to expand. As the universe expands, the amount of dark energy increases along with the distance between bodies of matter, which weakens gravity’s pull, allowing the push of dark energy to have more affect. Dark energy could also be caused by matter smaller than atoms acting oddly. The odd behavior of these small particles causes energy and matter to appear for very short instances and the constant appearance and disappearance could be the source of the dark energy within ‘empty’ space. There’s also the theory that dark energy itself doesn’t accelerate the universe’s expansion itself, but causes a new kind of force in the universe that only comes into affect once the universe reaches a certain size, or comes into affect, then accelerates the universe’s expansion for billions of years then disappears at random over and over again. However, these are all only theories, and in reality, anything new that we can learn about dark energy would be important because we know next to nothing about it. And if we know almost nothing about the substance that makes up over 70 percent of our universe, then how much do we really know about the universe itself?

This is why dark matter and dark energy have such a big impact on our knowledge of the universe; it tells us we aren’t even close to knowing as much about the universe as we thought we did. The day dark energy was discovered, astronomers went from knowing almost everything about the universe’s shape and age, to knowing almost nothing about over 70% of our universe. The discovery of dark matter put almost everything we know about gravity and how it works into question. Even the mathematics we’ve used to determine the size, shape, future, and many other things we know about the universe no longer hold true when dark matter and dark energy are factored in because we don’t know enough about them. There’s also much that might be changed if the existence of dark matter and dark energy were proved or disproved. If they are proved wrong, then the only explanation we could have from  the gravitational abnormalities they were meant to solve would be that are flaws in our current knowledge of gravity. Once the laws and theories were revised, how many of the things we ‘know’ based on gravity would be true? Could we still prove that black holes exist? Would the waves in the ocean still be caused by the moon? After we revised the theories and got the new facts, we may not be able to prove these things true anymore. On the other hand, if dark matter and dark energy were real, dark energy in particular, it could greatly affect our knowledge of the fate of the universe. There is a theory, called the Big Rip theory, where dark energy would make the universe continue to expand forever, and as the universe expanded, galaxies and other bodies of matter would be pulled away from each other until gravity becomes weak enough for cluster of galaxies to come apart, and galaxies themselves torn apart and so on until even matter itself is torn apart by the expansion.  Theories of the origin of the universe could also be validated by the existence of dark matter and dark energy, and by proving dark matter to be fact would in turn prove such things as MACHOs (Massive Astrophysical Compact Halo Objects) and/or WIMPs (Weakly Interacting Massive Particles) that are currently only theory. However, the greatest affect dark matter and dark energy has on astronomy is that there can be no progress toward a better understanding of the working of the universe, and maybe even a little regression, until we know more about dark matter and dark energy.

Once we do know what dark matter and dark energy are, though, there are many possibilities when it comes to what we might be able to do with them if they exist. Dark energy holds the most practical promise, as it might provide a source of pollution free energy that never runs out. If it were utilized, it could provide a form of renewable energy that was free like current renewable energy sources, but much more effective. Nikola Tesla might have already accomplished this when he utilized enough AC “radiant energy”, which may in fact be dark energy, to power a car. If we could figure out how this act could be duplicated, dark energy powered cars could eliminate the need for gasoline and reduce the cost to fuel a car. Dark energy also may have a much less probable, but much more revolutionary application in helping space traveling technology travel faster than light. The theory is that the universe is expanding fast than light travels due to dark energy, so if the dark energy in front of a space craft is decreased to the point of being negative, the affect would be the part of the universe in front of the space craft shrinking. If the dark energy were negative enough, thus the contraction of the universe severe enough, the space craft may be able to, theoretically, travel to the other side of the universe by traveling a much smaller distance. Of course, the amount of energy that would be needed to move the space craft just 33 feet by manipulating dark energy would be the same amount needed to turn Jupiter into pure energy, so even if we did know how to manipulate dark energy like this, we wouldn’t be anywhere near this kind of space travel. Dark matter could also be utilized for space travel, but as rocket fuel rather than a way to decrease distances. Because of the way dark matter particles are supposed to annihilate when they come into contact with one another, the amount of energy given off from the annihilation of one kilogram of dark matter would be about 10 billion times more powerful than an explosion from the same amount of dynamite. This would provide plenty of power to propel a space craft forward at high speeds. How we would obtain this dark matter, however, is a mystery, and how such a rocket would work is unclear. It’s also unclear as to whether or not dark matter is an unlimited or renewable fuel like dark energy. So for now, dark energy fuel and dark matter rockets are a long ways into the future.

Dark matter and dark energy aren't the same thing; dark matter pulls and dark energy pushes. Dark matter is the proposed solution to why gravity seems to be stronger than it should be and dark energy is a possible solution to why gravity isn’t as strong as it should be. They’re opposites in every fact except for one. When it comes to both dark matter and dark energy, we know so little, it keeps us from making progress in understand the universe. If it does turn out they exist, though, they could provide us with an unlimited, powerful source of energy. Either way, dark matter and dark energy is going to be a very important area of study in the future.




" dark matter/dark energy ." Mac OS X Server. N.p., n.d. Web. 23 Jan. 2011.

Biello, David. "What are dark matter and dark energy and how are they affecting the universe?: Scientific American." Science News, Articles and Information | Scientific American. N.p., 28 Aug. 2006. Web. 22 Jan. 2011.

"Dark Energy, Dark Matter - NASA Science." NASA Science. N.p., n.d. Web. 23 Jan. 2011.

"Dark matter - Wikipedia, the free encyclopedia." Wikipedia, the free encyclopedia. N.p., n.d. Web. 23 Jan. 2011.

"HubbleSite - Dark Energy - Fate of the Universe." HubbleSite - Out of the ordinary...out of this world.. N.p., n.d. Web. 23 Jan. 2011.

Marquit, Miranda, and Copyright 2006 PhysOrg.com.. "Is dark matter composed of sterile neutrinos?." PhysOrg.com - Science News, Technology, Physics, Nanotechnology, Space Science, Earth Science, Medicine. N.p., n.d. Web. 23 Jan. 2011.

Omega, the greek letter. "Martin White: Dark Matter." UC Berkeley Astronomy Department Home. N.p., n.d. Web. 23 Jan. 2011.

Stone, Alex. " The Birth of Dark Energy | Telescopes | DISCOVER Magazine ." Science and Technology News, Science Articles | Discover Magazine . N.p., n.d. Web. 23 Jan. 2011.

"Dark Energy As a Source of Power." EzineArticles Submission - Submit Your Best Quality Original Articles For Massive Exposure, Ezine Publishers Get 25 Free Article Reprints. N.p., n.d. Web. 24 Jan. 2011.

"Dark Matter Rocket." Next Big Future. N.p., n.d. Web. 24 Jan. 2011.

"Physicists: Faster-Than-Light Travel Might Be Possible - Science News | Science & Technology | Technology news - FOXNews.com." FOXNews.com | Fair & Balanced. N.p., n.d. Web. 23 Jan. 2011.

voltage. "Fuel-Efficient-Vehicles.org » Tesla Biography." FUEL-EFFICIENT-VEHICLES.org . N.p., n.d. Web. 24 Jan. 2011.