[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] – SuperStars

6 Nov

The stars… the givers of light, the givers of warmth, the givers of life…

These huge fiery furnaces have been burning brightly for billions of years and they will continue to light up the universe for many more to come. Our Sun is just one prime example of an ordinary, middle-aged star but stellar systems come in all shapes and sizes. In this issue we will uncover super massive stars and witness some of the most luminous objects in the universe.

The Sun, at the centre of our solar system, was integral to that of human existence, to large and our planet would be to hot for liquid water to form, to small and the energy emitted would not be enough to support the staples we rely upon. Our star is at exactly the right size and distance, 93 million miles away, for humans to bathe in its brilliant glory and prosper from its energy. The Sun is known as a ‘Yellow Dwarf’ star, it is at the middle of its life cycle or ‘Main Sequence’, the point of a stars life were it starts to burn its reserves in a bid to fight against the inevitable gravitational forces that will one day collapse it into a much smaller ‘White Dwarf’ star.

The sheer size of the Sun leaves our planet basking in the warmth of the radiation discharged from nuclear reactions going on under its surface. A super heated core converts hydrogen into helium at the temperature of 15 million degrees Celsius, compare that to the hottest Earth temperature of 70.7 degrees recorded in Libya and we can count ourselves lucky we are at the perfect distance. It is said that a million Earths could fit in the sun and that it is 750 times the size of all the masses of all the planets combined.

At this moment the star’s approximate size is thought to be near to 1,000,000 miles in diameter as it grows older it will start to expand outwards, past the orbits of Mercury, Venus, Earth and Mars as it uses up the last of its energy. Even at this inconceivable magnitude the star is still dwarfed by our next specimen 8,000 light years away.

Eta Carinae is a binary system, consisting of at least two stars orbiting each other, surrounded by a huge cloud nebula ejected from one of these stars in a mass explosion in the past. One of the stars is a smaller Wolf-Rayet star which burns slower and at a lesser temperature than its oversized blue neighbour. This star managed to stay stable for the time being but will be subject to a super or hypernova explosion in the near future, approximately in the next 10,000 to 20,000 years.

Supernova and hypernova explosions occur once a star has finished nuclear fusions and has exhausted its last reserves, this will lead to an eruption and total destruction, once gravity loses the battle, of the matter once holding it together. The size and class of the star determines what type of explosion it will endure.

This massive blue star, Eta Carinae, is 120 times the volume of the sun, which means if it was at the centre of our system it would extend beyond the distance of Jupiter, past the four inner planets and far beyond the asteroid belt that separates those rocky bodies from the outer gas giants.

Eta Carinae is a ‘Luminous Blue Variable’ (LBV), meaning its luminosity differs due to it pulsating irregularly; this aside this giant still burns at the brightness of 4 million suns. Although this star is younger than ours it is much larger, meaning these class of stars are able to produce an iron core at their centre, this is thought to one day cause Eta Carinae to go hypernova.

Another example of stellar behemoths that has its future yet to be determined is Betelgeuse(Beetlejuice) or Alpha Orionis. A red supergiant that is 300 times bigger than Eta Carinae and 500 times that of the sun. Placed at the centre of our solar system and the surface would reach out to twice the orbit of the planet Mars. Betelgeuse, due to its size, is the 10th largest star and its furnace is 14,000 hotter than our own. Sitting on the shoulder of Orion in this popular constellation, Betelgeuse has an uncertain future ahead of it. Running low on energy Betelgeuse is sure to explode into a supernova. When…? No one knows. It could happen in the next million years, it could happen this decade.

Betelgeuse (top left)

It is unlikely for this star to explode any time soon but it is not impossible, when it inevitably does happen Betelgeuse will appear as a second sun to us. Rivaling that of our own during the day and out shining the moon during the night. This will conclude in either the explosion slowly dimming out over the course of a few months, or turning into a gamma ray emitting pulsar sure to reign for thousands of years.

Finally we have our last remaining stars the brightest, Sirius and the largest VY Canis Majoris who both belong to the constellation Canis Major.

Sirius is also a binary star system like Eta Carinae but its major star Sirius A is our point of interest as it is the brightest of all the stars in the night sky. Sirius A is 23 times more luminous than our sun and double its size, quite small in comparison to some of the other stars featured above. Sirius used to be of huge significance to ancient civilizations that depended on the night sky for their survival. As time has moved on it held less importance due to technology helping us pinpoint ourselves on this planet but Sirius has still remained the brightest star ever discovered.

Sharing the same constellation as Sirius is VY Canis Majoris, of which this section of the night sky is named. It is massive, truly gigantic and is a bit of an anomaly. Being the biggest it is also one of the brightest, surprisingly unlike most other giant stars this is a single star system, consisting of just one red hypergiant, much like Betelgeuse but significantly larger.

If the Earth were to represent 1cm on a ruler then VY Canis Majoris would correspond to 2.3km.

If, like the others, it were placed in the middle of the solar system we call home. This star would end far beyond the orbit of the planet Saturn.

It is one billion times the size of the sun.

Much like Betelgeuse VY Canis Majoris will meet a violent end. Thought to occur in the next 100,000 years both of these red supergiants are expected to go supernova causing beautiful but dangerous eruptions that will eventually be recycled into new, possibly even bigger stars.

Example of a Hypernova

[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.

[COSMIC BODIES] – Frozen Oceans

12 Aug

Ever since man first started to gaze out into the skies, he has always wondered if he is alone. Is life possible among the millions of stars he could see or even just in this small band of planets we call the Solar System? Ever since man has had the aid to his eyes and knowledge of science, he has been able to come closer to the conclusion of that question.

Places like Mars and The Moon (Lunar) have always had romanticisms about alien life living on their surfaces, and as of yet we are still to proven wrong. I’d like to introduce two more alluring worlds among our Solar System that show decent signs of a habitat for E.T.

These worlds are far out into the more inhospitable regions of our host star system; they both orbit huge gas giant planets and both have a temperature that is lower than -150 degrees Celsius.

These worlds are the small icy Moons; Europa, who orbits Jupiter, and Enceladus, who’s host planet is Saturn. These worlds, although some distance apart, share a few similarities in the essential aspects for them to support life. Both moons share the most important of these, water, and lots of it. In fact, Enceladus is believed to be made up of 91% water vapor.

As a species we know that water is an essential building block for life, you only have to look around you for proof. So it seems entirely plausible that these moons can be the habitat for some bizarre marine life as there is already so much of it here on Earth.

Enceladus is a tiny moon, smaller than Great Britain, which sits in the E-ring of the planet Saturn, over 147,000 miles away from its host. Discovered in 1789 by William Herschel, the man who also discovered Uranus, Enceladus is the sixth moon of Saturnian orbit and the brightest object in the solar system. Believed to reflect 99% sunlight off its surface, Enceladus is small but an incredible find. Scientists are excited about this moon because of it’s surface appearance and subterranean goings-on.

In 2005 a probe named ‘Cassini’ was sent passed Enceladus with instructions to take photographs. The satellite took some amazing images of giant jets of liquid water protruding into outer space some 80 miles. This indicated the presence of liquid water and the possibility of a subterranean ocean beneath its icy surface.

The area of interest became known as the ‘tiger stripes’, a series of linear depressions on the surface indicating a raised temperature in the south Polar Regions. This proved the presence of an ice volcano fuelled by underground heat.

‘This finding is a crucial new piece of evidence showing that environmental conditions favorable to the emergence of life can be sustained on icy bodies orbiting gas giant planets’ – Nicolas Altobelli, ESA project scientist for Cassini.

No impact craters in the surrounding area also implies that this region is young, therefore ever changing. A spectacle this moon shares with her step-sister Europa.

Jupiters moon Europa

Europa is a Jovian moon, meaning it orbits within the realms of Jupiter, and is also one of four of the Galilean moons. Named by Galileo Galilei, in respect to a Greek queen, Europa was discovered in 1610, along with the three other closets moons to Jupiter. Although somewhat bigger than Enceladus, Europa is still smaller than our moon but with a high potential to preserve life due to its huge ocean. Scientists believe the surfaces layer, some -160 degrees Celsius, is tens of kilometers thick and the water layer below is thought to be 50 -105 kilometers deep, that’s more water than Earths oceans combined.  This leads scientists to believe that the shear size of the ocean underneath, in comparison to the size and diversity to life on Earth, that life on Europa is a mathematical certainty.

‘we calculate that the odds of finding life in the waters of Europa are 122 out of 123. The 122 known bodies of saltwater harbor microbial life. The 123rd body of saltwater, Europa’s vast ocean, is the body that has yet to be tested. Therefore, the odds are 122 of 123 in favor of finding life, or above 99%’– David Darling, part time astronomer and science writer.

Europa is close to Jupiter, so close that the massive planet exerts tidal pressures on the moon much like the relationship the Earth has with it’s lunar neighbour. This causes ‘plates’ on the moons surface to crack and move due to warm temperatures below the surface most probably caused by underwater hydrothermal vents.

This below surface phenomena is also true of Enceladus and as we recently discovered, on our planet, life does not necessarily require sunlight to exist.

Hydrothermal vents were discovered just in the last decade, they prove that life can go on without heat provided for it by the Sun. These vents send columns of water reaching temperatures of 460 degrees Celsius from the core and out into the depths of our oceans. Crabs, worms and bacteria like creatures were discovered to be living within this eco-system and thriving well without sunlight. It was clearly all down to these vents and the heat they were giving off that allowed complex life to live in such an extreme enviroment. Now scientists were excited because they thought that this could just as easily be true of any other body supporting water or water ice.

Underwater Hydrothermal Vents

So scientists from NASA and the European Space Agency (ESA) went on the hunt for worlds that looked like a suitable home for these hydrothermal vents and their answers were both Europa and Enceladus.

As mentioned before Enceladus has a satellite nearby already, named Cassini after the Italian/French astronomer of the 17th and 18th century. Launched in 1997 Cassini has beamed back tons of information surrounding Saturn and her moon system and will continue to do so for the 20-year duration of its mission.

ESA and NASA also had a similar, but far more advanced, probe that was scheduled for launch in 2020 in order to understand Jupiter’s moons Europa and Ganymede. NASA have since pulled out of the mission called, Europa Jupiter System Mission (EJSM) and have left ESA to fund its own quest to the region, Jupiter Icy Moon Explorer (JUICE).

Russian interests have also spurred this assignment forwards as they look to actually having a lander set up home on the moon. In an attempt to understand Europa’s icy surface and subterranean ocean the Europa Lander will be separated from the main rocket in order to carry out various fly-by missions. This launch looks likely to be scheduled far beyond its original date of 2020.

Until this mission we still have a lot to understand about both these moons complexity and intriguing imagery. They both leave us wondering just what lies beneath their surfaces and how much of it is Alien and how much is familiar.

For Galileo to have gazed up and wondered so much and known so little speaks the same of us today. With his help, along with Herschel and the understanding of the critical aspects of life, we can envisage, like Galileo did, the grandeur of celestial knowledge while still understanding so little.

[COSMIC BODIES] – What is WR-104?

26 Jul

What is WR-104 and does it pose a threat to Planet Earth?

Discovered only in 1998 poetically named WR-104 is massive star system located in the constellation Sagittarius. It is what is known as a binary star system consisting of a pair of stars orbiting each other. It takes roughly around 8 months for WD-104 (the name of the bigger of the two, WD meaning White Dwarf) and its OB-type partner (name given to a young, blue star) to orbit each other. Both will live for a few hundred thousand years, side-by-side, constantly ripping each other apart. Living this distance in time generally means all the stars are young which causes them to shine a brilliant blue or bluish white. Burning slightly less bright than a full moon, as seen by an observer, this star system has secrets that scientists have rushed to uncover in recent years.

WR-104 joins many other systems with the initials W and R, named after Charles Wolf and George Rayet, two French Astronomers who were the first to discover one of these massive stars in 1867. When these star types are described as massive it really means massive, not the biggest in the Universe but still nearly 20 times the mass of our own Sun. WR type stars have very short lives, in the scope of the universe that is, and exist for just a heartbeat compared to its celestial companions. Once they have used all their nuclear energy they go the same way as all stars by first collapsing in and exploding out. This explosion will release more energy in one second than our Sun will release in its entire life. Wolf-Rayet stars will burn 200,000 times brighter than the Sun due to solar winds that have ripped off its outer layers to reveal the inner core of hydrogen converting into helium gas combustion that burns this bright blue.

The star system is particularly interesting however due to the spiral shape dust remnants that are being dragged behind the orbiting bodies. This occurs because of the two interacting and compressing eachs radioactive material, which was left behind after their birth, causing it to follow the stars in their cosmic dance.

Another point of interest fixed to this star are its poles. Every celestial body has a north and south pole made clearer by its point of rotation or ‘wobble’. The reason why WR-104’s is so interesting is because scientists believe that one of the poles could be pointed straight at Planet Earth. ‘WR-104 is a fascinating object that got a lot of press last spring’, says Dr Grant Hill who works on the Keck Telescope, ‘Since the object is in our galaxy, it could be devastating [for Earth]’. The system is situated 4,800 light years away from the Sun but this is still close enough to be blasted by a Gamma-Ray burst that will be emitted when this star goes Supernova. Supernova is the name given to massive stars when they collapse and explode. This Gamma-Ray burst could stream through the cosmos and rip anything, thats in the way, apart. The radioactive beam would tear layers of the Earth’s crust from the core and deem all life extinct.

It is thought however that previous calculations of the star’s axis being 16 degrees of Earth are incorrect and the sum is now thought to be 30-40 degrees. So WR-104 doesn’t seem to pose as bigger threat than once feared…