Send the link below via email or IMCopy
Present to your audienceStart remote presentation
- Invited audience members will follow you as you navigate and present
- People invited to a presentation do not need a Prezi account
- This link expires 10 minutes after you close the presentation
- A maximum of 30 users can follow your presentation
- Learn more about this feature in our knowledge base article
Do you really want to delete this prezi?
Neither you, nor the coeditors you shared it with will be able to recover it again.
Make your likes visible on Facebook?
You can change this under Settings & Account at any time.
Transcript of Galaxies
formed and types of galaxies Galaxies What is a Galaxy? How do Galaxies form? Types of Galaxies The Milky Way Resources A galaxy is a space system composed of dust, gas, and millions or billions of stars.
The number of galaxies are countless; just from the observable universe there may be 100 billion. There are four main types of galaxies: Elliptical, Spiral, Lenticular and Irregular. The Milky Way, the galaxy we live in, is a typical barred spiral, much like billions of other galaxies in our universe. http://en.wikipedia.org/wiki/Galaxy
http://stardate.org/astro-guide/btss/galaxies/galaxy_formationhttp://www.jeffstanger.net/Astronomy/galaxyformation.html Elliptical Galaxies Elliptical galaxies are shaped like an elongated sphere.
The light coming off is smooth, the brightness decreases as you go farther out from the center. Elliptical and spiral galaxies are further classified using a system called the Hubble tuning fork. Edwin Hubble invented this system. Spiral galaxy A barred spiral is different than a normal spiral because it has a bar across the middle of it and it spouts two major arms. The center of the Milky Way is referred to as the “galactic bulge”. The bulge is full of dust, gas and stars which is why we cannot see 99.999997% of the stars in our galaxy. The center also includes a black hole in the very middle, billions of times as large as the sun. The Milky Way is in fact, a cannibal. When we were young, we ran into a lot of other galaxies, which we “ate”, and that added to our mass, making us very large and able to envelop other smaller galaxies. If you see this symbol: WRITE IT DOWN! It is probably
important! We may think we are a large part of the Milky Way, but in fact, there are around 400 billion stars in the Milky Way and scientists are led to believe there are at least as many planets! We have a “halo” surrounding us. It is a “halo” made up of dark matter that makes up 90% of the mass of the Milky Way! Another thing we cannot see is the actual galaxy. All pictures of the Milky Way is either other galaxies or simply just artists interpretations of what it would look like! Spiral galaxies look like spirals, with long arms winding from a bright bulge at the center. But if you looked at a spiral galaxy from the side, it looks like a thin disc with a bright bulge in the middle. A spiral galaxy is shaped like a disk, usually with a bulge in the center and with arms that spiral outwards. But sometimes spiral galaxies have a bar as well as arms. There's a center bulge with a bar through it then the arms coming off of that. Lenticular Galaxies Lenticular galaxies are just like spiral galaxies but they have no arms. They're just a bright center bulge. There are also barred lenticular galaxies which just have a bar through the center bulge how a spiral would have. Irregular Galaxies Elliptical galaxies contain older stars and very little gas and dust. An irregular galaxy has an undefined shape and has lots of young stars, dust and gas. One kind of irregular galaxies is a starburst and they shine very bright becuase there are so many new stars being born in a very short period of time. There are many theories as to how galaxies are actually formed. Difference in Formation -In spiral the star formation
forms slowly and forms a
disk shape Spiral -In elliptical star formation
is rapid and forms a
smooth shape Elliptical Less interactions
and isolation =
spiral galaxy Lots of successful
mergers = elliptical
galaxies Galaxy Collisions Interacting Galaxies When two galaxies pass by
each other, the force of gravity
interact and cause it to
bend out of shape. Galaxy
take millions of years,
so we cannot watch them happen COLLISION Milk Way Andromeda Spiral galaxies usually contain middle-aged stars along with clouds of gas and dust.