Galaxy Notes

• Our galaxy is _________________________.

• Galaxies are made up of• A. • B.• C.

Shapes of Galaxies

• Spiral or Barred Spiral

Elliptical Irregular

• Spiral Galaxy- A nucleus of bright stars and 2 or more spiral arms.

•Elliptical Galaxy- Spherical or flattened disk. Usually contains the oldest stars. (elder)

•Irregular Galaxy- No definite Shape. Usually the smallest in size.

Space Measurement• A light year is…

the distance light travels in 1 year. 1 LY= 9.5 trillion km. (Used to measure distances outside the Solar System.)

• An AU stands for ________________

The avg. distance between the Earth and the Sun . (Used to measure distances inside the

Solar System.) 1 AU= 150,000,000 km

1 AU

Radio Telescope• Radio telescopes: used to study naturally

occurring radio emission from stars, galaxies, and other astronomical objects.

The largest (in terms of collecting area) radio wave telescope is located in Puerto Rico with a diameter of 305 meters and is suspended over a valley. (Reflecting Telescope)Used to:•Detect objects in space•Map the universe

Radio waves pass freely through the atmosphere, SO it collects data 24/7, rain or shine.

Reflecting v. Refracting• The Arecibo Observatory in Puerto Rico is an

example of a REFLECTING telescope.

• Another type is the REFRACTING telescope.

Optical Telescope

• Refracting telescopes use a convex lens to magnify objects; reflecting telescopes use a concave mirror to collect and focus the light.

• Which is which?

Satellites

An example of a satellite used to get information is the Hubble Telescope.

• Placed in orbit and sends info. back to Earth where it is interpreted.

Uses: Predict weather, locating lost ships/ people, Satellite T.V., Cell Phones, GPS, takes images of other celestial objects.

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Tilts of Planets in the Solar System

• The “Red planet”, the surface of Mars is red in color. This is because of the rich iron oxide present on the surface.

• Mars possesses polar ice caps like Earth. They are made up of carbon dioxide and water.

• The size of the Great Red Spot is 3 times the size of the Earth and it has been lasting for more than 300 years.

• Uranus seems to be rolling on the orbital plane. Tilt: 98°

Dwarf Planets• ERIS

•CERES

•JUNO

Composed of more than 98 percent nitrogen ice, with traces of methane and carbon monoxide

•PLUTO

ASTEROIDS•VESTA AND PALLAS

Vesta

Ceres- Was considered a dwarf planet, why?

Pallas- What is it considered? Why?

• There are about 100 billion galaxies in our universe.

• If we plot all the visible galaxies on a graph, we will see something like this.

•Elliptical:• They usually consist of old stars.

• SPIRAL: MILKY WAY GALAXY

Draw this

• The closest star to our Sun is 4.24 light years away, its name is Proxima Centauri

The North Star is known as Polaris and is 430 LY away.

• A spectroscope works by breaking light into the wavelengths (or spectra) that make it up. Different wavelengths of light bend by different amounts, so it splits the light into its colors. Scientists can tell the elements present in a star by looking at its light through a spectroscope. Each element will have its own unique spectral lines of color, just as people each have a unique fingerprint.

SPACE PROBE• A space probe is a scientific space

exploration mission in which a robotic spacecraft leaves the gravity of Earth to explore places too dangerous for astronomers.

•

Mariner 9 First Space Probe to orbit MarsPicture of Mercury from Messenger

ObservatoryObservatory• Houses telescopes• Often have dome

shaped roofs• Used to monitor

space• Some are ground

based, some are space based (like Hubble)

Mauna Kea: Arizona

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