Tuesday, May 06, 2008

So long, and thanks for all the fish.

Astrobiologists at the Cardiff Centre have built a model of our solar system travels through our galaxy. Our solar system is on the outer edges of one of the spiral arms of the Milky Way, taking its sweet ole time to complete a complete revolution (around 250 million years, if I remember correctly). But that's not the only movement of the solar system. Apparently, it bounces up and down through the plane of the Milky Way every 35-40 million years -- and with each bounce through the plane, the solar system is exposed to a denser region of the galaxy -- the plane has much more stuff. A bounce through that stuff could lead to catastrophic events -- such as comets colliding with Earth. In fact, the 35-40 million year cycle coincides quite well with mass extinction events on Earth.

Now here's the bad news. We're up for another bounce through the galactic plane -- tomorrow in fact -- so place your head firmly between your knees, it's going to be a rough ride.

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Tuesday, March 11, 2008

The Day Before Genesis

In the mispent youth of science classes and houses of ignorance, where robed mystics babble incoherently, we were led to the belief that there was a beginning. That the beginning was something miraculous and mysteriious, and if we stared too long we'd probably go mad with more questions -- or worse, blind. In the beginning, there was nothing, and from it, everything emerged -- space, time and the very laws of nature.
The Man (Purusha) has a thousand heads, a thousand eyes, a thousand feet. He pervades the earth everywhere and extends beyond for ten fingers' breadth. The Man himself is all this, whatever has been and whatever is to be. He is the lord of immortality and also lord of that which grows on food. Such is his greatness, and the Man is yet greater than this. All creatures make up a quarter of him; three quarters are the immortal in heaven. With three quarters the Man has risen above, and one quarter of him still remains here, whence he spread out everywhere, pervading that which eats and that which does not eat. From him Virj was born, and from Virj came the Man, who, having been born, ranged beyond the earth before and behind. When the gods spread the sacrifice, using the Man as the offering, spring was the clarified butter, summer the fuel, autumn the oblation. They anointed the Man, the sacrifice, born at the beginning, upon the sacred grass. With him the gods, Sdhyas, and sages sacrificed. From that sacrifice in which everything was offered, the clarified butter was obtained, and they made it into those beasts who live in the air, in the forest, and in villages. From that sacrifice in which everything was offered, the verses and the chants were born, the metres were born, and the formulas were born. From it horses were born, and those other animals which have a double set of incisors; cows were born from it, and goats and sheep were born from it. [Source]
At one point in my life, that all made sense, and I was at peace knowing that I knew all there was to know. Then I got some education and it made me think, and doubts and questions arose. If Vishnu never woke up, would the world have been created?

I stopped pinning my hopes on the Big Bang after a while. The Big Bang implied something came before, and even though I wasn't supposed to ask, I asked -- quietly. Thinking of everything, at the vast scale of the universe to the weirdly, wonderous quantum scale, one can get lost. The human species may never find the answers before we go extinct, but that possibility isn't stopping us. In the April issue of Discover Magazine, Adam Frank teases us with three tantilizing prospects that dares venture beyond the Big Bang and conventional thinking. Cosmological heresey, if you will.

(1) The universe is more than we can see, and at the fundamental level, are one-dimensional objects called strings. The promise of string theory is the unification of general relativity and quantum mechanics -- and it's all dizzyingly complex mathematics, that may prove itself unobservable. There are many interpretations of string theory, including the possibility of dimensions beyond the four that we are familiar with. In this theory, our four-dimensional universe is a brane (short for membrane) inside a higher-dimension space, called the bulk. There could be many branes within a bulk, all with different laws of physics. Think of bedsheets hung out on clotheslines to dry in the summer. Each bedsheet would be a four-dimensional universe, flapping in the wind. When bedsheets touch each other in the bulk, the results materialize in the brane, like, well -- a miracle. One such effect would be the Big Bang. In this version of the universe, ours is but one in a multiverse. The concept of a beginning disappears, as universes are constantly being popped into the multiverse. Each new universe is a brane, that could likewise interact with other branes to create more branes, and so the multiverse continues.

(2) In seeking to explain the Big Bang and the resulting universe, the concept of inflation has been proposed -- and while the mechanism that precipitated it is not understood, it has made predictions that have been confirmed by observations. The universe as we know it today, is expanding from a distance past; seeming to originate from a single point; is flat; and in whichever direction we look, appears the same. The concept of inflation states that at some point in the beginning of everything -- perhaps just after the Big Bang -- the universe underwent a period where it expanded exponentially, driven by negative pressure vacuum energy; i.e. stuff appearing out of nothing, and flung out to create the universe. As crazy as it might sound, stuff does appear out of nothing, all the time. What if then, inflation isn't as unique as once thought, but occurs on quite a regular basis? The result would be a multiverse, in which the Big Bang really isn't unique, but is constantly happening. A multiverse of infinite, interconnected universes. An interesting outcome from this thinking is that time has no meaning. Our inflation only pushed time in the direction we experience it today. It could very well happen that other inflations have time running in the opposite direction.

(3) The craziest idea of the three, and my favourite, cause it seems to make the most sense, is that time is an illusion. Time doesn't exist. It's an idea proposed physicist Julian Barbour. In this theory, the universe is like pages in a book. Every page exists at the same time. There is no past, and no future. The flow from one Now (page) to another Now (page), produces the illusion of time (narrative) that we experience. In such a universe, nothing changes. Everything just is. This may sound crazy, but there is hard mathematics to support it.

If you're still here, you may want to check out some related reading. (The Adam Frank Discover article, The Day Before Genesis, isn't online as yet.)

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Friday, February 01, 2008

A Map of the Universe

The Universe
Ever wonder how large everything is? Well, at least the known universe? People have been wondering for a long, long time about it. Some folks over at Princeton produced this map published in 2005, in the Astrophysical Journal [PDF], of the known universe.
We have produced a new conformal map of the universe illustrating recent discoveries, ranging from Kuiper belt objects in the Solar system, to the galaxies and quasars from the Sloan Digital Sky Survey. This may projection, based on the logarithm map of the complex plane, preserves shapes locally, and yet is able to display the entire range of astronomical scales from Earth's neighborhood to the cosmic microwave background. The conformal nature of the projection, preserving shapes locally, may be of particular use for analyzing large scale structure. Prominent in the map is a Sloan Great Wall of galaxies 1.37 billion light years long, 80% longer than the Great Wall discovered by Geller and Huchra and therefore the largest observed structure in the universe.
Feel small?

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Thursday, January 10, 2008

OJ287: Really, really BIG!

Biggest black hole in the cosmos discovered
The most massive black hole known, has been discovered -- weighing in at a massive 18-billion Suns. And it gets better. This black hole is so massive, it has another black hole, weighing about 100-million Suns, orbiting it. The smaller black hole makes a complete orbit of the larger one every 12 years, ploughing through its accretion disk twice during an orbit. Each time the smaller black hole moves through the larger's accretion disk, huge outbursts of radiation is released, causing the system to brighten. The two black holes form the heart of the quasar QJ287. As general relativity predicts, astronomers have observed the decay of the smaller black hole's orbit. At the rate of decay, the smaller black hole will be swallowed by the larger in 10,000 years.

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Sunday, May 13, 2007

Bullet-Shaped Solar System

Asymmetric Heliosphere
As results from our various instruments pour in, we get an increasingly accurate view of our universe, and our place in it. Recently, researchers analyzing data from the Voyager spacecrafts, began to piece together an image of our solar system’s place within the galaxy. The solar system travels in an invisible bubble, created by solar particles streaming towards interstellar space. The edge of our solar system is in fact, defined as the point where particles from the Sun and those of interstellar space, reach a happy medium -- undulating against each other. Our solar system moves through the Milky Way, carving it’s way through interstellar space -- with the bubble of solar particles shaped like a bullet, forming a protective shell around the system. The edge of this bubble, carves a path through the Milky Way’s magnetic field at an angel of 60-degrees, traveling at 1/3 the speed of light. The bullet shaped is formed from the solar particles hitting the galactic magnetic field.

Ain't that cool?

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Thursday, May 10, 2007

They're Made of People!

We send a lot of stuff into space. A lot. Not everything that goes up and stays out there, necessarily had a primary mission. Upper rocket stages of spacecrafts for instance -- they're just there to make sure the crafts we send up, get to where they're going, and have a chance at completing their missions. Upper rocket stages -- well, they just sort of get left to their own devices when they've been spent. As Space.com points out in a recent article, an interesting possibility arises from that scrap metal. The spacecrafts that get sent out are usually sterilized to ensure they're clean -- not so with the upper rocket stages. They're teeming with bacteria from the engineers who built them. The amazing thing about bacteria is their ability to survive. Bacteria has been known to hibernate for millions of years -- waiting for the right conditions to arise so they continue doing what bacteria do -- multiple, and evolve. Right now, upper rocket stages are hurtling out of our solar system to destinations unknown. Space is quite large. Time is very long. With some wild imagination, the possibilities can be really freaky.

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Wednesday, April 25, 2007

Second Earth, Gliese 581 c

The Planetary System of Gliese 581
Astronomers using the ESO's 3.6m telescope, have discovered a planet orbiting Gliese 581, a red dwarf star, that bear a striking resemblance to Earth. The planet has a radius 50% larger than Earth, with five times more mass and is 14 times closer to its star. Its orbit allows the planet to complete an orbit in 13-days. At that proximity to its star, you'd think the planet would be hot, but because Gliese 581 is smaller, cooler and is less luminous that our star, this new planet may actually have comfortable temperatures, and possibly even liquid water.

Gliese 581 is just over 20-light-years away from us, in the constellation Libra. It belongs to the group of most prevalent and stable stars in our galaxy. Due to their low luminosity however, they are difficult to observe. While the newly discovered planet is gaining a lot of press lately for being Earth-like, the chances that the system could support life as we know it, is fairly small. While red dwarfs are stable, handing around for a lot longer than stars like our Sun, they exist with much variability, emit light mostly in the infrared and would most likely lock habitable planets close to them in a tidal orbit.

For more, see: The HARPS search for southern extra-solar planets : XI. An habitable super-Earth (5 MEarth) in a 3-planet system. [PDF]

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Tuesday, March 27, 2007

Hexagon on Saturn's North Pole

The Cassini spacecraft has sent images back of a weird, six-sided hexagon that covers the entire north pole of Saturn. The hexagon shape was first imaged by the Voyager 1 and 2 spacecrafts, and is 25,000 km across -- a size that could hold about four Earths -- and 100 km deep. The hexagon has a system of clouds that is whipping around in it, as can seen in movies made from the Cassini images.

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Saturday, March 17, 2007

Frozen Water Under Mars' South Pole

Researchers using the MARSIS radar instrument on board the Mars Express spacecraft have found a huge deposit of frozen water under Mars' south pole. If the ice was convert to water and placed on the surface of Mars, it would be enough to cover the entire planet 11 metres deep. A striking find -- which gives more support to evidence that water once flowed on the surface of Mars. Millions, or even billions of years ago, Mars may have resembled a young Earth, and had possibly supported life similar to that of Earth. The hunt continues.

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Monday, March 12, 2007

Stereo Eclipse

NASA's Stereo A and Stereo B spacecrafts, launched in the fall of 2006, are on a mission to study the Sun. The spacecrafts have each taken up position in Earth's orbit around the Sun -- with Stereo A being 1 million miles ahead of Earth in orbit, and Stereo B being 1 million miles behind Earth in orbit. The orbits have been planned to afford the spacecrafts the ability to create stereoscopic images and videos of the Sun -- specifically, coronal mass ejections.

On Feb. 25 however, Stereo B made a cool video. In an exercise to calibrate its CCD detectors, the spacecraft made a movie of the Moon transiting the Sun. A couple of remarkable things show up on this video. Since the spacecraft is further away from the Moon than we are, the Moon appears smaller than the Sun -- unlike how we would see it on Earth. Secondly, because the spacecraft's cameras see in the extreme ultraviolet, the colours of the Sun are just plain alien.

Check out the video below.

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Friday, March 09, 2007

Tvashtar's Plume

Tvashtar's PlumeThis image of Io was taken by the New Horizons spacecraft from a distance of 2.5 million kilometres away.  It shows the plume from the Tvashtar volcano, near Io's north pole, which extends to 290-kilometres from the satellite's surface.  New Horizons is currently going snap happy as closes in on Jupiter, on its way for the planned encounter with Pluto in 2015.  Click the thumbnail for the larger image and check out the alien volcano!

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