Definition of Astrophysics
Astrophysics is defined as the study of the universe based on physical laws and chemical properties of celestial bodies such as stars, planets, and nebulae (clouds from which stars are born). The researches in the field of Astrophysics also function to prove the existence of other systems present in our galaxy.
Introduction to Astrophysics
It is said that the first discovery clears the deck to many new discoveries. You might have been familiar with this legendary name Sir Issac Newton and his thick of things theory The Gravitational Theory - Every particle attracts every other particle in the universe with force. He was the first scientist to prove that the physical laws applied on Earth are also applicable Outside of the earth's atmosphere and deep in the universe.
Ten Historical moments which turned the boat of Astrophysics
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| Pc: NASA/ESA/Hubble Heritage Team(STScI/AURA) |
1. Dark lines in the solar spectrum
Sun, the head of the solar system family, mainly comprises Hydrogen - the first element of the periodic table. In an experiment in 1802 & 1814 dark lines were observed in the spectrum of the sun. When the sunlight was allowed to pass through a prism it formed a colour spectrum; alongside, there were dark lines quite clearly visible among the coloured spectrum. These absorption lines denoted the presence of calcium, magnesium, sodium and Iron; opening doors to chemistry and contributing as an aid to Astronomy.
2. Classification of stars into 7 types
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| Harvard Classification System |
Pickering et al in 1885 grouped 400,000 stars of space into 7 types. This accomplishment paved the way for spectroscopy in Astrophysics.
3. H - He: The internal composition of stars
Eddington in the 1920s hypothesised that the stars' internal core comprises hydrogen and helium. Based on this hypothesis Eddington also launched a paper - 'The internal constitution of stars. He said that the energy that comes as light from the stars is a consequence of the fusion of hydrogen and helium atoms inside the core of these stars.
4. Doctoral thesis of Cecilia Payne (1925)
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| pc: Science History Images/ Alamy Stock Photo |
Laying a foundation for stellar evolution in science, Cecelia Payne hypothesised that stars are nothing but the home to hydrogen and helium gases.
5. The expanding universe (Hubble's law)
It was the time when Astrophysics had discovered the Andromeda galaxy, conveying the truth that 'the milky - way isn't alone in the universe. Hubble's law states that the farther the galaxy in deep space the faster it moves away; which is believed to indicate that the universe is expanding.
6. Detection of Radio waves
Karl jansky in August 1932, at Telephone Laboratories, recorded radio waves coming from the centre of the milky way galaxy, in the direction of the Sagittarius constellation in space. The waves were of 20.5 MHz of frequency and repeated after every 23 hours and 56 minutes. Hence Radio Astronomy became a prominent branch of Astronomy.
7. Discovery of the first black hole (1971)
Two Astronomers of NRAO & Leiden Observatories found X -rays coming deep from space. The source of this x-ray was a supergiant star which is believed to be incapable of producing x-rays without being heated to million degrees by a companion. This supergiant star was named AGK2 + 35 1910=HDE 226868 and its companion which partnered with it, was Cygnus x-1, a black hole.
8. Discovery of the first Exoplanet
Have you ever thought of the existence of systems of planets revolving around a star other than the sun? Such planetary systems which revolve around other stars are scientifically termed 'exoplanets'.
On the 9th of January 1992 two radio astronomers, Aleksander Wolsczan & Dale frail announced two planets orbiting the pulsar PSR 1257+12.
By the 2nd of April 2020; science acknowledged 4,241 exoplanets in 3,139 systems with 691 planets having more than one planet. This benchmark discovery has paved way for extraterrestrial life.
9. Detection of gravitational waves (2016)
Gravitational waves were recorded in 2016. Researching the cause of its production, scientists came to the conclusion that gravitational waves are produced due to the collision of two black holes which are fusing to become a massive blackhole capable to gulp a galaxy.
10. First black hole image (2019)
April 10, 2019, witnessed a milestone in the history of Astrophysics when the first blackhole image was captured. The black hole was pointed to be the heart of the M87 galaxy.
Books to Refer if you're an Astrophilic
- Fundamental Astronomy - Kartunen kroger
- An introduction to Astrophysics - Baidyanath Basu
- Schaum's Outline on Astronomy - Stacey palen
- An introduction to the study of stellar structure - S.Chandrasekhar
- Astrophysical concepts - Martin Harwit
- Essential Astrophysics - Kenneth lang
Life is a chain of events, events are caused by our actions; So, never give up and hook; you can't guess!!! when the eureka moment would strike your chain of events.
-Author