2. ASTRONOMİ VE UZAY BİLİMİ
Astronomy and Space Science
Astrophysics

3. Galaxy
A galaxy is a massive, gravitationally bound system consisting of stars, stellar remnants, an interstellar medium of gas and dust, and an important but poorly understood component called dark matter.

4. Galaxy
The word galaxy is derived from the Greek galaxias (γαλαξίας), literally "milky", a reference to the Milky Way galaxy. Examples of galaxies range from dwarfs with as few as ten million (107) stars to giants with a hundred trillion (1014) stars, each orbiting their galaxy's own center of mass

5. The nuclear bulge and Galactic Center.
The Milky Way Galaxy
The Milky Way galaxy is a spiral galaxy consisting of over 400 billion stars,
plus gas and dust arranged into three general components as shown to the left: The halo - a roughly spherical distribution which contains the oldest stars in the Galaxy,
The nuclear bulge and Galactic Center.
The disk, which contains the majority of the stars, including the sun, and virtually all of the gas and dust

6. Andromeda Galaxy
The Andromeda Galaxy (/ænˈdrɒmɨdə/) is a spiral galaxy approximately 2.5 million light-years (2.4×1019 km) from Earth in the
Andromeda constellation.
Also known as Messier 31, M31, or NGC 224, it is often referred to as the
Great Andromeda Nebula
in older texts.
The Andromeda Galaxy is the nearest spiral galaxy to our Milky Way galaxy

7. Andromeda Galaxy
At an apparent magnitude of 3.4, the Andromeda Galaxy is notable for being one of the brightest Messier objects, making it visible to the naked eye on moonless nights even when viewed from areas with moderate light pollution.

15. Please watch the following video clip
You will be asked to answer some questions
about the theory in the clip

16. How_the_Universe_Works_S01E08_Part1

18. Definitions and Terms
GALAXY: A galaxy is a massive, gravitationally bound system consisting of stars, stellar remnants, an interstellar medium of gas and dust, and an important but poorly understood component called dark matter.
ACCRETION: This is the growth of a massive object by gravitationally attracting more matter, typically gaseous matter in an accretion disc. This is also a phenomena that resulted in the formation of many of the moons orbiting the planets in our solar system.
MOON: All moons have one thing in common –
They are all “natural satellites held in position by gravity”
Nebula A nebula is an interstellar cloud of dust, hydrogen, helium and other ionized gases. Originally, nebula was a name for any extended astronomical object, ...