Universe and Galaxy

Question 1

What is Astronomy?

Answer 1

Astronomy is the science which investigates all the matter-energy in the universe: its distribution, Composition, Physical states, movements and evolution. It is the study of the universe and the celestial bodies, gas and dust within it.

Question 2

What is Cosmology?

Answer 2

“Cosmology is the branch of science that deals with the scientific study of the origins and the evolution of the Universe and the nature of the Universe on its largest scale”.

Question 3

Who was Nicolaus Copernicus?

Answer 3

• Proposed a heliocentric (Sun-Centred) model of solar system.
• Astronomers believed that Earth was stationary at the centre of the solar system.
• Galileo attempted to publicise Copernican theory (Early 1600s) and was convicted of heresy as a result.
• His theory was accepted over 100 years after his death in late 17th century.

Question 4

What is CMB?

Answer 4

• CMB (The Cosmic Microwave Background)
• The afterglow of the
  BigBang.
• the heat was spread in the Universe then proportionally dropped.
• represents a temperature of 2.7 kelvin, which it self a microwave radiation.
• First evidence that the Universe had a Beginning.

Question 5

Who Discover CMB?

Answer 5

In 1964, Radio Astronomers:

• Arno Penzias
• Robert Wilson

Question 6

Who was Galieo Galilei?

Answer 6

• Italian mathematician, astronomer and physicist.
• Invented thermometer in 1593
• First one to use telescope.
• Discovered the rings of Saturn.
• Saw the four major moons of Jupiter.

Question 7

Who is the Father of BigBang theory?

Answer 7

George Lemaître in 1927

Question 8

About Bigbang theory?

Answer 8

• term coined by Sir Fred Hoyle in 1950.

* rapid expansion of space and time like blowing up a balloon.

Question 9

What are the Models of possible futures for universe?

Answer 9

• Closed Model (Contracting universe theory)
• Flat Model (Steady State Theory)
• Cyclic Model (Cyclic Universe Theory)
• Open Model (Expanding Universe Theory)

Question 10

What is Universe?

Answer 10

“The totality of everything that exists, including al matter and energy, the planets, stars, galaxies and the content of intergalactic space”.

Question 11

What is Galaxy?

Answer 11

• massive aggregate of stars,
• All bodies are gravitationally interacting and orbiting around common centre.
• 125 billion galaxies in universe.
• e.g Milkyway and Andromeda

Question 12

Type Of Galaxies?

Answer 12

• SPIRAL: contain middle age stars along with cloud of gas and dust.
• ELLIPTICAL: Older star and very little gas and dust.
• IRREGULAR: undefined shape and has younger stars, dust and gas.

Question 13

Milky Way?

Answer 13

• is the large, disk shaped galaxy that includes our solar system.
• contain 200-400 billion other galaxies.

Question 14

Features of Milky way galaxy?

Answer 14

• Milky way is a spiral galaxy
• diameter- 100,000 light years
• formed 14bn years ago.
• sun takes 250 ml years to orbit it.
• our S. system is 30,000 lightyear away from it centre.
• nearest galaxy is andromeda
• major arms of it are: Pursues, Sagittarius, Centaurs, Cygnus.