Tag Archives: The Sun

Venus in Transit

4 Jun Venus in Transit (Google)

Astronomy runs just like clockwork and the intricate workings are there for all to see, if you know where to look. This year and specifically this week you will have the opportunity to see it first hand. The planet Venus will pass between Earth and in front of our Sun giving us humans a rare glimpse at the motion of poetry the solar system offers.

Galileo, Joseph Kepler and James Cook have all observed this transit in the past and all have made their own calculations and written their own findings but much is still to be learned. The next and last transit visible for this generation will take place tomorrow night and continue into the morning of June 6th (GMT).

Now obviously it is difficult to view the sun during the night time so viewing it on the meridian line will be near on impossible. Opportunity comes very early in the morning just after the sun rises around 4.30 (GMT). The transit will begin the night before and carry on for 7 hours before climaxing at around 4.47(GMT).

Here is a map showing all the best locations to view any point of the transit courtesy of F.Espenak, NASA.

The fact is it will be extremely difficult to view the phenomena this time around and unfortunately the same event wont take place until 2117. The only way for us in the UK to view this sensation will be once it is over and images are released for us to marvel.

As upsetting as it is not to be able to view this first hand we are lucky enough to live in a world where these events are accessible to everyone in one form or another. So once the Goddess of Beauty has finished her journey across our star take a moment to think about the intricate workings of the Solar System and the beauty it offers us for our viewing pleasure.

Re-Birth of the Sun

24 Dec Three Kings follow Sirius

The end of the year brings celebration and thanks to the continual harvest and health of the Earth. December is a month of socializing with feasting and story-telling and no tale is greater than the Story of Christmas and Jesus Christ. However another tale has been unfolding in the night sky and is yet to end. The strange goings on, astrologically speaking, is maybe over shadowed by celebrations. Here is just a small insight into winter solstice and the link it has to the greatest story ever told.

Winter solstice, in the northern hemisphere, occurs when the axial tilt of the north pole is at its furthest distance away from our host star thus shrouding the northerly half of our planet in longer periods of darkness as the nights draw in. The sun is at its lowest point in the sky for the calendar year, slowly heading down to the horizon as the days become shorter and colder. This phenomenon takes place over the latter part of the month of December and has been said to conclude, in the northern continents, on the 25th day.

Throughout history this time of year has always been celebrated with feasting and holidays and with good reason as the halfway point of winter means spring is around the corner. On the 22nd day of December the sun is said to be in a fixed position in the sky as it has been slowly moving south on the horizon since the summer solstice in June. On the 25th the sun reportedly then moves one-degree north and closer to that of the prosperous months of the year. It is this astrological piece of ingenuity we are to celebrate and be thankful for.

The night sky has many links to that of biblical and other religious stories due to the way tales were interpreted in ancient times. For instance, again in the Northern hemisphere, astrological alignments have incredible links to that of the birth of Jesus and coincidences to many other religious figures.

The ‘Star in the East’ the bible refers to is the star Sirius, the brightest in the night sky, this is also at a specific low point in our orbit with the sun along with the constellation Orion and more precisely the three stars of Orion’s belt, that are all in continual alignment. These two parts of the star map also then align with the sun on the 25th day of December, the Sun’s lowest point and, according to legend, soon to be its ‘rebirth’. The three stars of the belt are also known as ‘The Three Mary’s’ or ‘Three Kings’. Many believe this is the story of Jesus and that the three stars ‘follow’ Sirius (the star in the East) to the birth of the Sun (Son).

These occurrences are in no way linked to the exact year of the birth of Christ but happen every Winter and also in the months of November and January. The stars are permanently aligned and will only ever be seen apart over thousands if not millions of years of Earth’s movements.

As celebrations continue to go on throughout this month take a minute to gaze upon the night sky and witness this sight as it means that spring is sooner here and therefore the time of prosperousness. The birth or rebirth of the sun is a time to be thankful for.

[COSMIC BODIES] – SuperStars

6 Nov Sizes of Stars

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