Space, A Journey Beyond the Sky

Space, A Journey Beyond the Sky.

You are never too late to thank the first man whoever at first thought that space is conquerable. You can’t chase a goal unless you set it before. So, the first man who dreamt of setting a journey to space, whether unknown; still deserves thanks from all of us. Although he lived several thousand years before Christ (or more), we followed his particular thought to spread our territory to space and we are pushing our limits more today. 

Yes, indeed, a term like ‘Astronomy’ is not the result of that specific man rather it’s the combined effort of a lot of people ranging from the age Before Christ till today. If we cannot find out him from the past, at least some others made continuous hard work to bring us space. 

As you can assume the number of scientists or scholars related to astronomy is enormous, here are some mentionable illustrations of some of the major incidents and contributions of them. You can have a bird’s-eye view over the timeline of astronomy and get a proper idea about the journey of their knowledge that took place before the first spaceship launched.  

From 2000 BC to 1000 BC:

Most of the civilization was active in this period and they left their footprint in the arena of astronomy. The Mesopotamians invented the constellations of Leo, Taurus, Scorpius, Gemini, Capricorn, and Sagittarius and that helped them to make a list of the passage of the Sun, the Moon and the planets throughout the year. Around 1600 BC, the Sumerians and the Babylonians developed the earliest astronomical records and star catalogs. They also recorded the position of the planets and solar eclipse dating on clay tablets and built the first solar and lunar calendar. In 1450 BC, the Egyptians built sundials to calculate time using sunlight. The Chinese did not remain behind in this race. They started keeping astronomical records in 1000 BC. Clever, weren’t they?

From 1000 BC to AD:

“The earth moves around the sun”- this universal truth was first proposed by Yajnavalkya, an Indian astronomer. He came up with a concept that the Sun is at the center and the Earth is spherically encircling the sun. In 750 BC, Mayan astronomers calculated the 18.6-year cycle in the Moons setting and rising. From this, they created tables containing the movements of the Sun, Moon and the planets. 

600 BC is the starting point for the Greek scholars to enrich astronomy with their knowledge. We have so many of them like Anaxagoras, Pythagoras, Thales, Plato, Heraclides and Aristotle. Some of them were in the opinion that the earth is at the center of every other planets including the sun and moon. 585 BC is the time when Thales of Miletus predicts a solar eclipse.

Anaxagoras was probably the bravest philosopher of that time because he suggested stars are little suns and we don't feel their heat on earth for their vast distance. The people of his age did not like his ideas and exiled him from Athens for spreading atheism (as this idea was against their religion at that time). Besides explaining eclipses correctly, he attempted to explain rainbows and meteors. Did you know that he was the first to explain Moon borrows its light from the Sun? Yes, he is the one to explain it first. All his efforts range from 467 to 450 BC. 

In 400 BC, the Babylonians showed us the perfect use of the zodiac as they divided the heavens into 12 equal parts each containing 30 degrees. Plato’s school named the ‘Platonic Academy’ promoted the idea that the earth is at the center of everything in 387 BC. While Aristotle described a geocentric universe, Heraclides explained the motions of planets and stars at that time. 

But in 280 BC Aristarchus of Samos defied this belief. On the contrary, he proposed heliocentrism in his model with the sun in the middle and the earth revolves it. Many people did not like his idea at that time but indeed it is the truth proven 1800 years later. The Aristarchus model has an estimation of the distance between the earth and the sun. No one before 270 BC estimated the size of the earth but Eratosthenes made this estimation accurately.

In 240 BC, the Chinese astronomers recorded the earliest sighting of Halley’s Comet. The recording is useful for modern astronomers for predicting the orbit changes accurately. Another notable incident of that time is Eratosthenes of Cyrene (now in Libya) discovery that measures the circumference of the earth with surprising accuracy! The Babylonian astronomers also recorded the sighting of Halley’s Comet 76 years later in 164 BC.  

Hipparchus, a Greek scholar, developed a star catalog for the first time. His catalog covers over 850 of the biggest stars in that accurate star map. Roman Empire introduces the first Roman calendar based on the solar system in 45 BC. In terms of star cataloging, Shi Shen made a tremendous effort to catalog 809 stars from 122 constellations.  He also observed the sunspots very clearly at first.

From 1 to 1000 AD:

The first most important work of this millennium is Greek astronomer Ptolemy’s star catalog listing 48 constellations in 150 AD. In his masterpiece ‘Almagest,’ he endorses the geocentric (Earth-centered) view of the universe and chartered the motions of the stars and planets. Surya Siddhanta, a Sanskrit treatise on Indian Astronomy, gives the average length of the sidereal year in 400 AD. The length is 1.4 seconds longer than the modern value. So what? They are the first to prove 365 days makes a year.    

Why we do not fall from the earth when it rotates?  Yes, because of gravity. This smart discovery was by Aryabhata, an Indian mathematician, and astronomer in 499 AD. The whole solar system is geocentric because of gravitation and the planets spin on their axis in an eccentric elliptical way. He also proved that the moon and the earth borrow light from the sun. That also proves the earth's rotation on its axis causes day and night and the sun’s rotation around the earth causes the year. 

Another Indian mathematician-astronomer Brahmagupta recognizes gravity as a force of attraction for the first time in 628 AD. He also describes the second law of Newton's law of universal gravitation in his Brahma-Sphuta-Siddhanta. 

From 773 AD the Arabians astronomers came into being. They started translating Aryabhata and Brahmagupta’s work from Sanskrit to Arabic. They also translated Surya Siddhanta. In 777, Yaʿqūb ibn Ṭāriq and Muhammad al-Fazari translated Brahmasphutasiddhanta and Surya Siddhanta and compiled them in a book named Zij al-Sindhi. But the Zij al-Sindh published by al-Khwarizmi in 830 is the most notable work by the Arabian astronomers. In this, he illustrated the movements of the Sun, the Moon, and the five planets known at the time.

al-Farghani wrote Kitab fi Jawani in 850. The book besides giving a brief summary of Ptolemy’s cosmography corrected Ptolemy according to the findings of the Arab astronomers. He gave revised values of the precessional movement of the sun and the moon and the circumference of the earth. This book was also translated into Latin for its influence.  

The Baghdad School of Astronomy is another milestone for the Arabian astronomers. Al Mamon founded the school in 813 AD. Astronomer Mohammad al-Fazari constructed astrolabe (a circular device used for measuring the movement of stars) in 928 AD and it was an advanced instrument for them at that time. This device helped to measure the positions of stars and planets and thus Arabian astronomy flourished to the next level. 

From 1000 to 1900 AD:

In 1054, the Chinese astronomers observe the supernova in Taurus and this is further clarified when we find this in Native- American rock carvings showing the star close to the moon. Nicolaus Copernicus explained his theory that the earth moves around the sun in his book ‘De revolutionibus orbium coelestium’ published in 1543. 

Hans Lippershey, a Dutch eyeglass maker, invented the refracting telescope in 1608. It was a revolution in astronomy.  Followed by the revolution, Johannes Kepler came with his book ‘New Astronomy,’ published in 1609. This book contains his idea of three laws of planetary motion. In 1610, Galileo Galilei finds spots on the sun, craters on the moon and four satellites of Jupiter. He also proved that everything does not orbit the earth. Isaac Newton built his ‘Newtonian telescope’ (the first reflecting telescope) in 1668. His famous book ‘Philosophiae Naturalis Principia Mathematica’ was published in 1687. This book is about the theory of gravitation and laws of motion.

Edmond Halley measured an interval of the comets from 1456 to 1682 in 1705 AD and predicted that it will appear 76 years later in 1758. It was named after him as an honor when the prediction came to reality. William Herschel, an amateur astronomer discovers the planet Uranus in 1781 which he thought was a comet at first. In 1784, Charles Messier publishes his catalog of star clusters and nebulae and suggests not to mix them up with comets. William Herschel used a prism to split sunrise through it in 1800 and built the foundation of spectroscopy. 

Ceres is the name of the first asteroid and Giuseppe Piazzi discovered it in 1801. By using the method of stellar parallax, Friedrich Bessel calculates the distance to 61 Cygni. It was a great achievement to measure the scale of the universe. After studying the sun for 17 years, Heinrich Schwabe gave a clear idea about the sunspots having a regular cycle in 1843. In 1846, German astronomer Johann Gottfried Galle discovered Neptune. Konstantin Tsiolkovsky, a Russian and Soviet rocket scientist published an article in 1895 about the possibility of space flight. 

From 1900 to 2000 AD:

In 1901, the Henry Draper Catalogue is published. In this comprehensive survey of stars, Annie Jump Cannon suggests a sequence of classifying stars by their spectra lines absorption which is still in use today. Ejnar Hertzsprung shows a relationship between color and absolute magnitude in the majority in the Milky Way Galaxy of the stars when he establishes the standard for measuring the true brightness of a star in 1906. Albert Einstein published the final form of the theory of general relativity in 1916 and German physicist Karl Schwarzschild uses his theory to lay a groundwork for black hole theory.    

"Andromeda Nebula" is a galaxy and Edwin Hubble discover that in 1923. He also discovers the universe expansion and another farther away a galaxy is moving away from us faster. This idea shows Georges Lemaître to found his initial “Big Bang” theory in 1931. Clyde Tombaugh discovered the dwarf planet Pluto in 1930. The trace of radio waves was not anymore, an unsolved mystery as Karl Jansky detects them in 1932. In 1948, the American scientists started to use the largest telescope. 

The space-age begins in 1957. Russia sends its first artificial satellite, Sputnik 1 into orbit and America sends Explorer 1 four months later. In 1958 the USA established NASA. The space competition between the two states started in 1959. Both launch their probes to the moon but Russia is the winner. 

Yuri Gagarin, a Russian astronaut becomes the first person to orbit Earth in April 1961. Mariner 2 and Mariner 4 by NASA are the first probes to reach another planet in 1962. Scientists discover the weak radio signals coming from all parts of the sky in 1965. A pulsar is an object that emits a regular pulse of radio waves. It is detected in 1967. The US wins the moon in 1969.   

The first space station Salyut 1. Russia launches the station in 1971. NASA’s two probes arrive at Mars and took pictures in 1976. NASA builds Space Shuttle Columbia (the first reusable Space Shuttle) in 1981. Scientists launch IRAS, the first infrared astronomy satellite in 1983.

The year 1990 added a new chapter in astronomy. The Hubble Space Telescope provides quality images of distant stars, nebulae, and galaxies. In 1992, the telescopes become more precise with computerized processes. Michel Mayor and Didier Queloz discovered 51 Pegasi b (the first exoplanet) in 1995. ISS (International Space Station), the huge space station covering most of the countries, including the USA and Russia was launched in 1998.  

From 2000 to now:

Mike Brown and his team effort direct them to the discovery of a number of objects including Eris, Sedna, Makemake, Haumea beyond Pluto in 2005. Being larger than Pluto, it is called the tenth planet. It also proves that Pluto is a dwarf planet. The International Astronomical Union (IAU) provides a new definition of planet and classified objects as dwarf planets in 2006. Meteoroid has great impact on the earth and we have seen the direct impact of 2008 TC3 over Sudan in 2008.   

Suvi Gezari's team at Johns Hopkins University used the Hawaiian telescope Pan-STARRS 1 in 2012 and proved the existence of black holes visually. In October 2013, the first extrasolar asteroid is detected near white dwarf star GD 61. The USA becomes the first nation to explore all the nine major planets as they completed a successful encounter with Pluto by using NASA’s New Horizons spacecraft in 2015. LIGO also detects gravitational waves that year. European Southern Observatory Discovered Exoplanet Proxima Centauri b around Proxima Centauri in 2016. 

A neutron star collision occurred in the galaxy NGC 4993 in August 2017 producing gravitational-wave signals and gamma-ray. This gravitational-wave having a simultaneous electromagnetic signal is a milestone for multi-messenger astronomy. 1I/2017 U1 (Oumuamua) is believed to be the first interstellar asteroid because it leaves the solar system after entering into it and passing the sun. 

In 2019, China made a successful attempt to complete a soft landing on the far lunar side by using Chang’e 4. The Event Horizon Telescope Collaboration gets the first image of a black hole at the center of the galaxy M87 in April 2019. The images with general relativity provide more evidence that supermassive black holes exist and we are going to find them soon.