Black holes in the universe

I would have never thought that I would be able to photograph a black hole with my own digital camera. But with some of these new super cameras it is now possible.

My Sony HX300 is capable of shooting stars with a 50x zoom, but with the internal zoom that increases the magnification to 3000x plus it is possible to see into the backgrounds behind the close stars and photograph galaxies and black holes.

Just lucky I guess, but in a corner of  one of my photographs I was able to photo enhance it through Photoshop and produce the following image.

It shows a few galaxies if you look closely, but one of the galaxies is shown in a curve. This is a classical distortion caused by a black hole. The black hole’s gravity is so intense that the space around the dense star is distorted and anything behind the black hole can be seem in this arc like distorted fashion.

This black hole is not at the centre of a galaxy but seems to be a rogue wandering black hole.

Black Whole in top right hand corner

Black Whole in top right hand corner

Identifying black wholes in the sky is almost impossible but because of the intense gravitational field around these stellar objects we often see a phenomenon called gravitational lensing. This effect bends the light from the distant galaxy around the intense gravity of the black hole in the for ground.

This affect of gravitational lensing can also be seen with other large masses of material. These gas clouds are non light emitting masses like black wholes but are not dense like black wholes. However, because they product some gravitational effects can also bend light from distant galaxies. Theory has it that a large part of the universe is made up of this dark matter. It is thought that much of the grey areas of the above photograph is related in some way to the effects of dark matter.

However, principally, the gravitational lensing effect in the right hand top corner of the photograph is identifying the location of a very massive object with a huge gravitational influence on the light from the distant galaxy causing the galaxy to look like an arc instead of an ellipse similar to the galaxy in the middle lower right hand corner of the same photograph.

 

by David Holland

 

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Achernar the elliptical Star

When you start to investigate some of our stellar neighbours you get a variation of characteristics presented to you. I think that Achernar is probably one of the most surprisingly unusual stars we have this close to the sun.

It is 139 light years from us although this figure seems to be quite elastic as other references put it at 144 lys from us. It is a hot class of star B3 Vpe main sequence still fusing hydrogen into helium as our own sun is, but has a luminosity of 2900 to 5400 time the sun.

It has a temperature ranging from 10,000 to 30,000 K but sources give an average of between 14,500 to 19,000K.  So that means it is in the colour range of Blue-white.

Its shape is unusual as it is not spherical as our Sum. It is an oblate ellipse. Actually, if you were to take some notice of the photographs below it is even more irregular in shape that this description made by other commentators which say that it is the least spherical star in the Milky Way galaxy studied to date. Its proportions are roughly 12:7.7 as a ratio of height to girth.

It has a estimated mass per unit volume of some 6 to 8 times the Sun and 7 times the Diameter of the sun assuming this is about its minor axis.

Even though it is rotating at 225km/sec it still takes 2.2 earth days to make one revolution.

Achernar

Achernar

This Photo show the star emitting gas from the end we will arbitrarily call the both pole.

Since the star is rotating at such a fast speed it is loosing a great deal of mass particularly from its equator. But because the star is loosing mass it is probably spinning at an ever increasing rate of spin.

Let’s assume that the star was spherical at one time and a large body collated with it glancing the star in such a way as to transfer energy to the star to rotate at a new faster speed. At the time this happened the star may have lost some mass, but at the faster rotation it continued to loose mass because the centrifugal force for many of the heavier gas particles was not enough to be counteracted by the gravitational pull of the star.

This put the star into a cycle of loosing mass and spinning faster. The theory of the conservation of angular motion says that as a particle becomes closer to the centre of mass it will spin faster around the mass. If we consider each atom of helium produced by the fusion process to be in an atmosphere around the star, each will move away from the star by centrifugal forces. as this happens the star becomes thinner at the equator and as a result the energy in the mass of the remaining particles in the atmosphere have to remain at the same energy level as a result start to move more quickly. With a spin period of 2.2 days and a speed of 225Km/sec it is easy to calculate the stars girth. With this it is again possible to work out the forces involved in the escaping gas from the star.

If this process were to continue the star will become quite an unusual type of star.

Colour saturation showing dark areas

Colour saturation showing dark areas

This Photo of Achernar shows the north pole at the bottom of the frame and was taken 10 days later than the first at the same time of night. This means that this photo is looking at the reverse side of the star from the one above and the one below.

You now can see some of the very hot gas around the star that has escaped the star’s atmosphere.

In addition you are able to see darker areas on the stars surface. these are not cooler areas but areas that are not producing visible light or light the camera can see. they may be  highly magnetic areas similar to our own sun.

Also it is easy to see this star as even more irregular that a simple oblate ellipse.

Hot and cold part of the star

Hot and cold part of the star

Finally, this photo was manipulated by reducing the brightness and increasing the contrast. If more contrast were used you would see a much darker area in the equatorial areas of the star. This agrees with stella commentators who suggest that these areas are cooler that the poles. This photo again shows the north pole at the top of the photo.

Article by David Holland

Al Nair the 31st brightest star in the sky

Al Nair is a hot blue class B sub giant star. It is in the constellation of Gruis. At a temperature of 13,500 Kelvin it is emitting a blue-white light. With characteristics of 2.3 times as hot as our sun , 3.6 times the radius of the sun and 380 time the luminosity of the Sun, it is still considered to have similar chemistry to the Sun although in the last stages of the process of burning Hydrogen.

It is a wild sun, spinning at a rate of 236 km/second at its equator, which means that it rotates one full revolution in less than a day.

The photograph of the star below has court the star in such a way as to allow the viewer to see two faces in the swirling gases at its surface. One face is a devilish face facing to the right and down of in the frame and the other is a big brain alien face looking straight at the viewer.

Although there are two distinct faces, some people can only see one face. See it you are clever enough to see both faces

Alnair - Star in Gruis

Alnair – Star in Gruis

At 101 light years from earth the star is not in our close neighbourhood, one sixth of the way to Betelgeuse which is 640 light years away.

The photograph was taken in December 2013 by the Sony super camera HX300 with a 50 times optical magnification and a 200 times overall magnification. The camera specifications included a 20.4 mega pixel sensor. The frame was then magnified 8x internally in the camera and a photo internally recorded. Then a further magnification was made of approximately 2.7x. This is a total magnification of about 4300 times.

The Photo was takes on Manual with an ISO setting of 3200 and a shutter speed of about 1000th of a second.

Article by David Holland