Astronomy for GCSE







Astronomy... Further Reading

Whilst reading about the Sirius Binary system [referred to in 3. Astronomy Through the Ages] I found a news report about another:
Startling evidence suggests the ancient Egyptians understood the inner mechanics of [the] binary star system [Algol - also known as the Demon Star], spinning through our skies 93 light years away...

The binary system... was first noted in modern astronomy by a John Goodricke, back in 1783.

The Egyptians were huge star-gazers, taking copious and accurate notes about changes in the heavens, and using these to form predictions about lucky and unlucky parts of the day.

When Finnish researchers studied the Cairo Calendar, a badly-damaged but readable calendar highlighting the good and bad days of a year in 1200BC, they came to some startling observations.

For the Egyptians not only made observations, they made conclusions and calculations to figure out the inner mechanisms of the stars for their charts.

Two cycles were spotted in the Cairo Calendar. One lasted 29.6 days - almost exactly that of the lunar cycle.

And the other was 2.85 days - which researchers from the University of Helsinki in Finland ascribe to the Algol system.

And as the Egyptians made very specific calculations, their figures appear to have solved a very modern puzzle.

The Algo system has now been confirmed as a tertiary system - three stars in total.


I then found this paper [source] "Algol as Horus in the Cairo Calendar: the possible means and the motives of the observations" (to read at a later date)

Algol is known colloquially as the Demon Star... The association of Algol with a demon-like creature (Gorgon in the Greek tradition, ghoul in the Arabic tradition) suggests that its variability was known long before the 17th century, but there is still no indisputable evidence for this...

The variability of Algol was noted in 1667 by Italian astronomer Geminiano Montanari, but the periodic nature of its variations in brightness was not recognized until more than a century later, when the British amateur astronomer John Goodricke also proposed a mechanism for the star's variability...

This system ... exhibits x-ray and radio wave flares. The x-ray flares are thought to be caused by the magnetic fields of the A and B components... The radio-wave flares might be created by magnetic cycles similar to those of sunspots, but because the magnetic fields of these stars are up to ten times stronger than the field of the Sun, these radio flares are more powerful and more persistent...

Algol is about 92.8 light-years from the Sun, but about 7.3 million years ago it passed within 9.8 light-years of the Solar System[39] and its apparent magnitude was about −2.5, which is considerably brighter than the star Sirius is today. Because the total mass of the Algol system is about 5.8 solar masses, at the closest approach this might have given enough gravity to perturb the Oort cloud of the Solar System somewhat and hence increase the number of comets entering the inner Solar System....

The name Algol derives from Arabic رأس الغول raʾs al-ghūl : head (raʾs) of the ogre (al-ghūl) (see "ghoul"). The English name Demon Star was taken from the Arabic name.

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It seems to me that a number of (more recent) astronomers have show an interest in such star systems. Take William Herschel for example (mentioned on the Astronomy Through The Ages page).

It is said in Patrick Moore's book 'Astronomy for GCSE' p.14:

"[William] Herschel did his best to measure the distance of the stars. He selected pairs of stars (doubles) because he believed that one member of the pair would be much closer than the other, so that the second star would be in the background, so to speak; in this case there should be a regular apparent shift due to the Earth's motion round the Sun. In fact, no such shift was detected, because most double stars are physically-associated or binary pairs, moving through space together and at the same distance from us."

[To be continued...]

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