Wednesday, October 31, 2012

Some of The Strangest Things in The Universe


I thought in honor of Halloween, I might blog a little bit about the strange but true. I figured it might be fun to discuss some of the wackiest things about our universe that although seem utterly impossible or unlikely, are very true and help to fill this universe with the awe and wonder that will hopefully inspire everyone for generations to come. I've created a list of some of the things I've found very strange, but fascinating about our universe, in no particular order of course.

1. BLACK HOLES

One of the most amazing phenomena in our universe for a long time was thought only to be a theory. Conceived accidently by Albert Einstein while explaining his theory of relativity, black holes are a point in spacetime where gravity has become so strong, that nothing, not even light can escape its grasp.

A black hole is created when a very large star, one that is three to five times the mass of our own star, or 3 to 5 solar masses, collapses in on itself, producing a supernova and leaving its black hole corpse behind. At the very heart of every star is an engine of nuclear fusion that fuses hydrogen atoms into helium, the explosion created when the atoms fuse together becomes the fuel of the star. Because stars are so massive, they have very large gravitational force that continually pushes against the surface of the star. At the same time, the star’s inner fusion is creating outward pressure that counteracts the force of the gravity pushing inward. It’s a very real balancing act that is taking place in every star, even our own Sun. But this star is bigger than our Sun, as the star’s hydrogen fuel begins to run out and less helium can be fused, the star begins its expansion phase. The star will continue to expand, as it does, it begins combining helium into heavier elements: Lithium, Beryllium, Boron, Carbon, Nitrogen, Oxygen, etc. It will continue to fuse elements together as the star expands, and only when it begins to fuse Iron, is the star on its final countdown. The problem with iron is that the amount of energy needed to fuse elements into iron exceeds the amount of energy released by the fusion itself. Because the iron fusion process begins absorbing energy instead of radiating it, the star can no longer sustain the pressure needed to keep gravity from collapsing it, and the star begins to collapse in on itself. Within seconds the star will explode but not before gravity crushes all the remaining elements into heavier ones at the core. The star explodes, sloughing off its layer of elemental particles and tossing them into the cosmos. Then suddenly without any energy left, gravity collapses the remaining core into an infinitesimal point of extreme gravity, the black hole.

Once believed to be a terrifying reality of gravity that is the harbinger of doom, a deeper understanding of the process has left scientists understanding that although black holes certainly mean death, they are also critical to life as their process has helped seed our universe with the elements necessary to create life.

An example of a stellar black hole.


2. NEUTRON STARS

Not all stars become black holes when they supernova, because not all stars are large enough and have enough mass for that to occur. Some stars become even stranger objects when they die than a black hole.
Neutron stars form when a star with mass equivalent to about three solar masses collapses into a supernova, but the process is halted because the gravitational mass of the star was not big enough to cause it to collapse further, the outer layers of the star containing elemental particles are sloughed off, leaving behind a stellar remnant comprised almost entirely of neutrons. Neutron stars are so dense that a teaspoon of its material would weigh 5.5×1012 kg or 5,000 million tonnes.

Artwork depicting a neutron star.


3. MAGNETARS

As if Neutron Stars were not weird enough, some Neutron stars form into something stranger called the Magnetar.  Magnetars form when a newly formed spinning Neutron Star with a perfectly aligned magnetic field and enough heat, causes it to convert heat and rotation into magnetic energy. The resulting stellar remnant becomes a dense magnet of pure neutrons. So dangerous are the effects of magnetars that a small change in the surface of a magnetar, can cause a quake on the star that would burst energy that could be felt as far as 50,000 light-years away, that’s halfway across our own Milky Way galaxy. The electromagnetic energy would be strong enough to fry unshielded electronic equipment.

Actual NASA photo of a distant magnetar.

4. PULSARS

When a Neutron Star forms, if its angular momentum is strong enough, it can emit electromagnetic beam of energy from its axis which shines outward like the beam of light coming from a lighthouse. As the star spins faster and faster, the star’s light appears to pulsate, hence its name: Pulsar.

Actual NASA photo of distant pulsar.


5. SUPERMASSIVE BLACK HOLES

When scientists went snooping at the center of our Milky Way galaxy, they discovered that something odd was occurring there. Around the center were dozens of stars that appeared to be orbiting very quickly around an invisible object, at seemingly astronomical speeds. Typical stars move through space around 220 km/s. These orbiting stars were moving around this invisible object around 5,000 km/s, approximately 22 times faster than our Sun moves through space, indicating a massive gravitational field. But when scientists looked with telescopes, they saw nothing was there. Scientists then began to examine the orbit of these stars over time and could see that each orbit had a common focal point. Toward its center there is a faint radio emission scientists dubbed Sagittarius A, which doesn't seem to be moving much at all, indicating that it’s tied to something much more massive. When you examine the mass around Sagittarius A, you reach something of a lower limit of 4 million solar masses. Astronomers can't see the galactic center well enough to measure exactly how large Sagittarius A is, but they can say for sure that its radius is no larger than about two-tenths the distance between the Earth and the sun. That means that something 4 million times more massive than our own Sun fits inside an area that would fit the orbit of Mercury, astronomers could only draw from this one conclusion. At the center of our galaxy lies a supermassive black hole. Intrigued, scientists began looking at other galaxies, and were astonished to find that each galaxy they looked at appeared to have at its center a supermassive black hole. Scientists now believe all galaxies have them.

There has been much speculation as to why they exist, and where they came from, but much of that remains a mystery. Most scientists believe that these supermassive black holes formed from very massive stars that formed long after the big bang, during its infancy, when galaxies were still forming. As the gas and dust coalesced, the supermassive black holes pulled the gas and dust together, allowing smaller stars to form, and the angular momentum of the supermassive black hole continued to spin the galaxy allowing everything within to coalesce. In a very real sense, all galaxies owe their existence to black holes, without which nothing would have stuck together. It is believed that the angular momentum that continues to spin the black holes allows galaxies to rotate continuously, moving everything throughout the universe.

Example depiction of supermassive black hole.

6. QUASARS

Until recently, Quasars were kind of a mystery. Much of why they exist remained a mystery, but due to the discovery of supermassive black holes, quasars can be more easily explained. A Quasar is a very energetic and active galactic nucleus. Quasars are very luminous and some of the brightest objects in the universe and are responsible for much of the light that can be seen at the center of some galaxies. Quasars are believed to be the compact region of space that surrounds the supermassive black hole at the center of each galaxy. It’s powered entirely by the accretion disc surrounding that black hole. Quasars emit a radio signal that can be picked up as x-rays and gamma rays extend outward from its center.

Actual NASA photo of a distant quasar.


7. GAMMA RAY BURSTS

When a star goes supernova producing a black hole, the black hole begins sucking everything in around it. Much of what is left of the star that hasn't escaped its gravitational grasp begins being deposited into the black hole’s event horizon at a tremendous rate. So much material begins passing through this tiny hole in space that eventually the black hole burps, sending out a burst of pure gamma radiation, so bright it will outshine anything else in the universe, and vaporizing everything in its path for thousands of light-years. So powerful are these bursts that if a star exploded within close relative distance to Earth that produced a gamma ray burst in our path, it would wipe out all life on Earth. It has also been observed that primordial galaxies produced massive gamma-ray bursts at their center during formation, an occurrence that can now be explained by supermassive black holes.

Actual NASA photo of gamma ray burst.


8. NEUTRINOS

Neutrinos are tiny almost massless particles that pass seemingly through everything, all the time, with no interaction. Neutrinos do not carry electric charge, which means that they are not affected by the electromagnetic forces that act on charged particles such as electrons and protons. Neutrinos are affected only by the weak sub-atomic force. Because of this neutrinos can pass through matter completely unimpeded. Neutrinos are produced in a variety of ways, either through the process of nuclear fusion in a star, or as a result of supernova, or even through radioactive decay.

Actual image of neutrinos interacting with other particles.

9. COSMIC MICROWAVE BACKGROUND RADIATION

When the universe was in its infancy, before the formation of stars and planets, it was smaller, much hotter, and filled with a uniform glow from its white-hot fog of hydrogen plasma. As the universe expanded, it cooled off. When the universe cooled enough, protons and electrons could form neutral atoms. These atoms could no longer absorb the thermal radiation, and the universe became transparent. As photons began freely flowing throughout the universe, their wavelengths increased over time, as it expanded and they grew less energetic. This produced a glow that could be seen uniformly throughout the universe and could be picked up by radio telescopes as a hum.

This hum is evidence of our universe’s beginning, and before we switched our televisions to a digital signal, the Cosmic Microwave Background Radiation could be felt, anytime a television network went off the air, leaving static on your television.

WMAP reading of the Cosmic Microwave Background Radiation

10. DARK MATTER

When scientists with apparently a lot of time on their hands wanted to know how much the universe weighed, they began adding up all the matter in the universe and came to an astonishing inaccuracy. If you account for all observable matter in the universe, there is a large chunk of matter that cannot account for what is actually out there. That means that the universe weighs more than it’s letting on. This didn't make a whole lot of sense, so a scientist by the name of Fritz Zwicky hypothesized that there must be some type of matter out there that cannot be seen, and must account for the missing matter. He dubbed this phenomena dark matter. After years of calculations we now know that dark matter accounts for 84% of all the matter in the universe and 23% of the mass-energy. So much of the matter that exists today, is completely unseen, and undetectable by modern instrumentation, however  there are indicators to suggest that dark matter really does exist.

When scientists began looking into galactic formations they observed that in some galaxies density of star formation could not account for enough gravity and kinetic energy to keep the stars in the galaxy. The only plausible explanation why a galaxy with stars so far from each other could hold themselves together gravitationally would be if there was some force that was holding them together. This force is dark matter. If the matter unseen between stars, accounted for the missing gravity, it would explain that much of the matter in galaxies is actually dark and it’s this binding force that holds things together.

NASA Hubble map of dark matter.


11. DARK ENERGY

When scientists convinced that the expansion of the universe was slowing down peered into the universe for a look, they made an astonishing discovery. Not only was the universe not on the verge of collapse, but indeed its expansion was accelerating exponentially. This meant that galaxies were accelerating away from each other faster and faster as time passes. Scientists have come to dub this mysterious phenomenon as Dark Energy. Once you account for everything in the universe something amazing happens, Dark Energy accounts for 72% of all the mass-energy in the universe today, 23% of it accounted for by Dark Matter, and only 4.6% of it from Atoms. That means all the galaxies, planets, stars, moons, comets, asteroids, and life account for almost nothing. The universe is mostly made up of stuff we can’t see or detect, and remain partially a mystery.

Because of Dark Energy, ultimately the fate of our universe has already been decided. Eventually the light from galaxies will be too far from each other to ever reach, and the light inside each galaxy will slowly fade over time. As each star fades away into darkness, without a supply of new hydrogen, no new stars will form, and eventually all the light in the universe will go out and all that will be left is a cold, dark shell of a once brilliant existence. And on that day when the last star’s light dims out for the last time, like a candle in the wind, the universe will breathe its last breath, and its last light, will go out, and it will die, cold, alone, in the vast emptiness.

Example of web-like effect of Dark Energy, pervasive in universe.

12. QUANTUM ENTANGLEMENT

When quantum particles interact physically and separate, sometimes they take on the characteristics of each other. This means that two particles become a pair, which otherwise would not have. It has been shown that this pair will remain identical until a measurement is taken, at which point one particle will decide to change its characteristic, which then forces the other to take on this characteristic as well. What seems most amazing about this phenomenon is that entangled particles can change other particles even over vastly large distances, where it would seem that a connection would be impossible. In lab experiments entanglement has been used for the first time to teleport information from one position to another. If ever the possibility of future Star Trek type transporters exists, it will be from the work with quantum entanglement that such a thing becomes possible.

Depiction of two particles entangled together.

13. QUANTUM TUNNELING

Quantum tunneling is an effect where a particle can pass through a barrier it would not normally have the energy to surmount.  Because of Heisenberg’s uncertainty principle on particles that disallows a certain amount of knowledge to ever be known about the particle, the probability of a particle passing through a barrier becomes as probable as it would not. Thus a particle can borrow energy from the barrier that it is interacting with, allowing it to pass through it, effortlessly, and then simply discard the energy. And this is where it gets really weird, because the energy of the particle cannot be measured accurately, the particle can be in many places on its way to the barrier including passing through and being on the other side. It is only when such a measurement is taken, that the particle decides its position. So for a time, the particle is indeed in every place it could be, in front, inside, and on the other side of the barrier.

Example of quantum tunneling physics.

14. NEBULAE

Nebulae are extremely large clouds of dense, hot, dust, gas, and plasma. Nebulae which can span light-years across are the birth place of stars. It is in this dense cloud of material that the amazing process of star formation begins, when gas and dust coalesce into new baby stars. This stellar nursery is responsible for the cluster formation of thousands of stars to form in galaxies.

Actual NASA photo of Eta Carinae Nebula

15. LIFE

Maybe the strangest thing to come out of our universe is found in abundance on our planet Earth. Life is a wonderfully mysterious result of billions of years of cosmic evolution. And as much as we do know about how life evolved, we still know little about the chemistry that allowed it to form in the first place. As we expand ourselves outward in our own universal backyard, we look to places inside our own solar system that we believe will have life.

Three candidates with the best possibilities are Jupiter’s little moon Europa, and the moons of Saturn, Titan and Enceladus. Europa is a small moon covered in ice marked with a cracked eggshell-like appearance that suggests reformation. Because of the intense gravitational pull of Jupiter it is believed that beneath its icy surface lies a deep liquid ocean of water, a natural womb for the possibility of life outside our own planet. Saturn’s moon Titan is another candidate for the possibility of life, besides Earth, it is the only known place in our solar system with liquid lakes. Although Titan does not have water per se, its liquid lakes of methane, and endless hydrocarbon rain, allow the possibility of life to form. It is believed that for life to form liquid is necessary in whatever form, because it is only through the natural motion of liquid that interaction of molecules can occur freely. And although water is not in the equation for Titan, its liquid-formed lakes of natural gas do allow for life to form chemically. But maybe the best chance for life to form in our solar neighborhood beyond Earth lies on the icy moon of Saturn called Enceladus. When NASA’s Cassini photographed geysers of hot water spewing from cracks in its surface, it meant that below the surface of that moon exist reservoirs of liquid water, heated by the gravitational pull of Saturn on the little moon. And if liquid water exists, so does the possibility of life.  

Actual photo of unlinked DNA under a microscope.

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