galaxies and the expanding universe

GROUP 1Leader: Elyssa BelenMembers: Leonard Faraon Angelyn Cabisuelas Paula Garingan Madeleine Pasco Kyla Roxas Christine Sornito

What is Galaxy?

It is a massive total of stars, with some gas and dust, held

together by gravity.

TYPES OF GALAXIES

Spiral Galaxy In 1936, a spiral galaxy is a

certain kind of galaxy originally described by Edwin Hubble.

Spiral galaxies consist of a flat, rotating disc containing stars, gas and dust, and a central concentration of stars known as the bulge.

These are surrounded by a much fainter halo of stars, many of which reside in globular clusters.

Elliptical Galaxy The most abundant

type of galaxies found in the universe.

Elliptical galaxies are

dim.

They contain less gas and dust.

Irregular Galaxy An irregular galaxy is a galaxy that

does not have a distinct regular shape, unlike a spiral or an elliptical galaxy.

They are often chaotic in appearance, with neither a nuclear bulge nor any trace of spiral arm structure.

They are among the smallest galaxies and are full of gas and dust. 

Universe

It includes planets, moons, minor planets, stars, galaxies, the contents of intergalactic space, and all matter and energy.

Also called the “Cosmos” The word universe derives from the Old

French word univers, which in turn derives from the Latin word universum.

The expanding has been going on since the “Big Bang” probably around 20 billion years ago.

Expanding UniverseEdwin Hubble was an American astronomer that made the

observations in 1925 to prove that the universe is expanding.

In 1929, he also definitively demonstrated that the universe was expanding, and formulated what is now known as Hubble's Law.

He proved that there is a direct relationship between the speeds of distant galaxies and their distances from Earth.

He has been called one of the most influential astronomers since the times of Galileo, Kepler and Newton.

Do you wonder if the universe will ever stop expanding?

One way to stop expanding

Enough mass

“Critical density”

Universe is more dense than critical, the gravity of all the stuff in the universe will be able to overcome the expansion, causing it to stop, and eventually re-collapse.

Thank you for listening!

TIME!

QUESTIONS:

1-2.) Galaxy is a massive total of stars, with some _____ and ______, held together by gravity. 3–5.) Give the three types of galaxy6.) This type of galaxy is the most abundant and they contain less gas and dust. 7.) It is also called the "cosmos" 8.) He is the American astronomer that made the observation in 1925 to prove that the universe is expanding. 9.) The type of galaxy that does not have a distinct regular shape.10.) The word universe was derived from old French word.

ANSWERS:

1-2.) Gas/Dust

3-5.) Spiral, Elliptical, Irregular

6.) Elliptical Galaxy

7.) Universe

8.) Edwin Hubble

9.) Irregular Galaxy

10.) Univers