From Al-Khwarizmi to Johannes Kepler

800 years long journey explained.By: Bilal Karim Mughal

Tycho Brahe14 Dec 1546 – 24 Oct 1601

Danish nobleman

Known for accurate planetary observations

Refuted Aristotle and Ptolemy’stheories about the Universe.

Tycho BraheIn November, 1572, Tycho Brahe observed

the Supernova SN1572

Built an observatory “Uraniborg” in 1576

Tycho BrahePresented Geo-Heliocentric explanation of

the Solar System

Prepared detailed star charts with accurate timings, without any telescope.

Achieved supreme accuracy in predicting the positions of celestial bodies

Johannes KeplerDec 27, 1571 – Nov 15, 1630

German Mathematician, Astronomer, and Astrologer

Famous for his Laws of Planetary Motion.

Johannes KeplerWorked as Tycho Brahe’s assistant for 2

years

Tycho did not trust Kepler, allowed him little access to his data

Tycho Brahe asked him to develop an explanation of the Solar System

Johannes KeplerTycho never believed the Planets to be

orbiting the Sun.

Kepler was unable to match this with Geometrical Models.

Finally in 1609, Kepler gave Laws of Planetary Motion, describing that the Planets orbit the Sun.

The QuestionWas it purely the work of Tycho Brahe and

Johannes Kepler that led to the current understanding of the Solar System?

Era of Muslim ScientistsSpans over 600 years.

Significant improvements in Geometry and Mathematics.

Development of more sophisticated instruments like Sextant, Astrolabe.

Muhammad ibn Musa Al-Khwarizmi 780 – 850 C.E

Mathematician, Astronomer, Geographer

Developed the Tables for movements of Sun, Moon and 5 planets in 830. A.D

Muhammad Ibn Jabir Al Battani858 – 929 C.E

Determined the value of Solar day to be 365 days, 5 hours, 46 minutes and 24 seconds.

Made significant advances in Trigonometry.

Abd al-Rehman Al SufiDecember 7, 903 – May 25, 986

Wrote “The Book of Fixed Stars” in 964

Observed and described the Stars, their magnitudes, and their positions

Abu-Mahmud al-Khujandi940 – 1000 C.E

Persian Mathematician, Astronomer

Accurately computed the tilt of the Earth’s axis to be (23.53°) in 994 A.D

Abu Rayhan Al-Biruni 973 – 1048 C.E

Believed the Earth rotated about its own axis and around the Sun

Wrote 35 treatises on Astronomy

Abu Rayhan Al-Biruni Calculated the circumference of Earth

Believed in spherical Earth therefore

Also discovered that gravity exists within the heavenly bodies

Ibn al-Haytham965 – 1040 C.E

Proposed the Earth's rotation  on its axis in  The Model of the Motions

Abu Said al-Sijzi945 – 1020 C.E

Persian Mathematician, Astronomer

Suggested for the first time, the heliocentric system,

in which Planets orbit the Sun

Al-Biruni agreed with his ideas

Nasir al-Din al-Tusi1201 – 1274 C.E

Built an observatory at Maragha

Made accurate tables of planetary motions

Calculated the Precession of Equinoxes

Mirza Muhammad Tariq Ulugh Beg1394 – 1449 C.E

In 1424 built an observatory at Samarkand

Found the values of trigonometric tables up to 8 decimal places Determined the Earth’s axial tilt to be 23.52

degrees

Mirza Muhammad Tariq Ulugh BegCalculated the value of Sidereal year to be

365d, 6h, 10m, 8s (only 62 seconds more than the present estimation)

Taqi al-Din Muhammad ibn Ma'ruf1526 – 1585 C.E

Built an observatory at Istanbul

Wrote 33 treatises on Astronomy

Taqi al-Din Muhammad ibn Ma'ruf

Paved the way for the transfer of Islamic knowledge to the West

Developed an Astronomical Catalogue more accurate than Nicolaus Copernicus and Tycho Brahe

Final astronomer of Muslim Era

ConclusionTycho Brahe was the champion in observations

Kepler was successful in presenting the true image of Solar System

But the real pioneers of it were Muslim scientists of Medieval times who had researched for more than 400 years and had founded the base for Tycho Brahe and Johannes Kepler

ReferencesDictionary of Scientific Biography (1970)

Encyclopedia of the History of Arabic Science by Regis Morelon and Rushdi Rashed

The Touch of Midas: Science, Values and Environment in Islam and the West by M.A Kettani

Astronomy and Mathematics by Carra de Vaux