Tag Archives: Galaxies

[COSMIC BODIES] – When Galaxies Collide

16 Sep

Collisions within the Universe are essential for its continued existence. Mass explosions and impacts will endure to take place like they have done for over 13 Billion years since the Universe’s birth. Asteroids, moons, planets and even stars all go through this process of death and re-birth via impacts, but what about whole clusters of stars? Even galaxies some 200 million light years across are also victim to this force of nature. What are the consequences and what has this got to do with us?

Our galaxy the Milky Way sits across the sky as a smokey band of stars and nebulae. From the Southern Hemisphere you can see this band stream elegantly above the horizon. Obviously it is difficult for ourselves to see our galaxy side on, so we take from examples of similar galaxies of size and characteristics. We live within what is known as a ‘barrel spiral galaxy’ consisting of up to 400 billion stars, some 120,000 light years across. Beauty is usually followed by complexity in the cosmos and nothing seems more complex than a system of this many stars heading straight for one another.

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Two such systems that are currently entangled together are NGC 4038 and NGC 4039 or ‘Antennae Galaxies’ part of the NGC 4038 collection of galaxies.  Currently this system appears like a heart in the sky, seeming to be interlocked at the centre, sending the outer stars spiraling in tails across the cosmos. This phenomenon started to occur some 700 million years ago and is scheduled to continue for at least the next 400 million. As they continue in this mesmerizing cosmic dance, stars will career past each other at over 650,000 mph. A hurtling mass of stars, moons, planets and cloud will stream past each other narrowly missing while chaotically disrupting the laws of physics.

Magnetic fields will be thrown upside down and around and round, climates will be thrown into turmoil as atmospheres are ripped from the surfaces of moons and planets. This vision of hell is hard enough to compromise let alone imagine. The chances of life surviving while under this gravitational entanglement seems unlikely and most certainly impossible when you consider the ‘Stephan’s Quintet’ collective or ‘Pandora’s Cluster’.

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Named after it’s discoverer Edouard Stephan in 1877, ‘Stephan’s Quintet’ is a major galaxy cluster which features 4 out of 5 close galaxies combining into quite a spectacular tango of stars. Found within the Pegasus constellation these four galaxies span a distance of 340 Million light years at nearly the same distance from Earth. Pandora’s Cluster (Abell 2744) is a very similar in quantity to Stephan’s, as in the combination of galaxies but they are somewhat different. Pandora’s bunch seems to be at a rather different stage. There are more gases present around the cluster suggesting that friction and gravity have super-heated the space around the collision and somewhat spread out the destruction. Stephan’s Quintet and Pandora’s Cluster are marvelous examples of the sheer power and force the Universe has to offer. The force that goes into these types of collisions has the same amount of energy as the expulsion of more than 100 Million Supernovae. Unbelievable.

Positives to take away from these cataclysmic events are that in actual fact collisions are extremely rare between the stars and planets that populate these regions. It is hard to believe that an event of this size and quantity of objects, that nothing hits one another. Well it is that fact of size again. Infrequent collisions indicate that the distances between each star are still to great to affect each other. However, being in the middle of one of these events is not good news and our planet, like millions of others it is on course for a cosmic tango with death.

Our galaxy ‘The Milky Way’ is heading straight for our neighboring spiral galaxy, ‘Andromeda’ at over 310,000 mph with no brakes. Both galaxies tails will interlock first twisting into one another as the force of gravity builds and builds between all the smaller masses inside. Planets will start to spin and distort with the force pushed upon them by an invisible nature. Magnetic fields protecting any sort of biospheres or atmosphere will be torn from their surfaces. Unsettled centrifugal forces will reverse orbits, disrupt cores and tear apart worlds. Stars will heat up and expand outwards away to the external reaches of their solar systems engulfing everything in the already uninhabitable heat.

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For the moment we are safe, from Andromeda at least, this collision isn’t scheduled to take place for at least another 4 Billion years, more than a quarter of the existence of the entire Universe.

Regardless of the small chances of stars colliding it is still a reality. This is sill however not the end of the world (providing no planets are involved). Collisions of this power and energy will eventually settle into new nebulae creating hundreds if not thousands of new stars.

Collisions of this magnitude breads life and death into the cosmos. Where there is catastrophe in clashes there is creation within the remnants.


[COSMIC BODIES] – Galaxies Far Far Away

19 Sep

When humans think about distances in space, it is almost impossible to comprehend the vast expanse in between different masses. In a humans mind circumnavigating the globe is a huge deal, the time it would take is almost inconceivable let alone the distance. Scientists however will continue to strive in order to see further into the universe and therefore longer back in time. Images are just starting to reach us of some of the oldest known bodies within the universe and lots more discoveries are sure to come; hopefully with the notion of letting us understand where we come from.

Until recently the oldest known objects in space, except the universe itself, have thought to be stars, or gamma ray bursts as these stars explode, but now there is evidence to suggest that the galaxies, containing these stars are much older than thought previously. The universal limit for age is set by the boundaries of the universe, which is considered to be as old as 13.75 billion years old. These galaxies come pretty close to this age, in astrological terms.

Galaxies consist of a huge collection of stars orbiting a central core; this is thought to be a super-massive black hole, although this is not yet official. Galaxies range in sizes, our galaxy, the ‘Milky Way’, is thought to contain between 100 billion and 400 billion stars. Our closets neighboring galaxy ‘Andromeda’ is thought to have a mass of three trillion stars with a diameter of 250,000 light-years.

A light year is a measurement of distance, unsurprisingly, the distance it takes light to travel in one year. Light travels at a speed of 186,000 miles per second that is 671 million miles an hour. Keep that astronomical speed in mind as we delve further into the cosmos.

In September 2009 a group of astronomers handling the ‘Hubble Ultra Deep Field Telescope’ (HUDF) came across what was soon to be spectroscopically confirmed as the furthest, and therefore the oldest, object to be discovered in the universe.

What the scientist had found was a galaxy some 13.1 billion light-years away, meaning it was only 600 million years younger than the universe itself.  Scientists believe that galaxies only start to form at a limit of 200 million years after the Big Bang, meaning that this galaxy was formed during what is known as the ‘Reionization Epoch’, a period in which galaxies were forming at the fastest rate.

This galaxy was soon to be named by those who found it as UDFy-38135539 or HUDF.YD3 and it even featured on the television series presented by Professor Brian Cox, ‘Wonders of the Universe’.

Arguably it is a small galaxy registering one billion stars that covers just one- tenth the diameter of the Milky Way. However when thinking about those numbers it gives even the experienced travellers amongst us severe jet lag.

Now here is the even more exciting bit…

As soon as January of the next year an even older galaxy was discovered and this now holds the record for the oldest known object in the cosmos. Similarly named UDFj-39546284 is roughly 150 millions years older than the previous, although it has not yet been spectroscopically verified.

It is thought confirmation of this galaxy will occur when NASA and ESA launch the James Webb Space Telescope (JWST) planned for 2018. ESA also have another telescope in range in which they hope to have operational at the beginning of the next decade. The European-Extremely Large Telescope (E-ELT) will help us not only understand how galaxies and planets are formed but should aid us in looking into the recesses of the universe in a hope to understand where we came from and ultimately where we are going.