Earth Science

“The Sun-Earth-Moon System”

Tools of Astronomy

Radiation

Telescopes

Satellites, Probes, and Science Based Astronomy

Radiation

Light is a common term for electromagnetic radiation. Which consists of electric and magnetic disturbances, traveling through space as waves.

Naked eye only sees limited range of all various wavelengths.

Radiation

Now use the back of your Earth-Moon scale to draw illustration of wavelengths and frequency at the top of page 748.

Radiation

Electromagnetic radiation is classified by:Wavelength - distance between peaks on a

waveFrequency - the number of waves or

oscillations occurring per second.

Radiation

There is a mathematical relationship between frequency and wavelength.

Frequency is related to wavelength by:

c = speed of light (3.0 X 10^8 m/s) = wavelength f = frequency Note that all types of electromagnetic radiation travel

at the same speed, because c is constant.

Telescopes

A telescope collects light from a distant object and focuses it at a point where the image of the object can be studied or recorded.

Telescopes

4 benefits of telescopes: Ability to attach different detectors to telescopes to

observe all wavelengths A telescope brings much more light to focus than

the human eye can Allow astronomers to use specialized equipment Telescopes can be used to make time exposures,

light is collected over a long period of time. Why telescopes are able to detect objects that are too faint for the human eye to see.

Telescopes

Refracting telescopes- uses lenses to bring visible light to a focus

Reflecting telescopes- bring light to focus with mirrors

Although both refracting and reflecting telescopes are still in use today, the majority are reflectors

telescopes

Radio telescopes - reflect radio waves into electrical signals that can be stored in a computer for analysis.

Interferometry - is the process of linking separate telescopes together so that they act as one telescope.

Satellites, Probes, and Space-Based Astronomy

Astronomers often have to send their instruments into space to collect the information they seek.

Earth’s atmosphere blocks infrared radiation, ultraviolet radiation, X rays and gamma rays.

Close up pictures are needed.

Spacecraft

In addition to making observations from above Earth’s atmosphere, space-based exploration can be achieved by sending spacecraft directly to the bodies being observed.

Human Spaceflight

A multi-country space station called the International Space Station is the ideal environment to study the long-term effects of space. It started in 2000.

Spinoffs

Space-exploration programs have benefited our society far beyond our increased understanding of space.

Spinoffs - technologies have been passed on to commercial industries for common use.

1400 different NASA technologies have been passed on to commercial industries. Cordless tools, pumps for artificial hearts

Earth Science

“The Moon”

Reaching for the Moon

Astronomers have learned much about the Moon from telescopic observations.

Most of our knowledge comes from explorations by space probes and astronauts.

Lunar Properties

Our moon is unique to all the moons in the solar system It is one of the largestFarther from earth than most moonsSolid and rockyOnly large moon of the inner planets

Lunar Surface

Albedo - the amount of sunlight that the surface reflects Moon 7% Earth 31% No atmosphere, so sun heats surface to 127

degrees C. Absences of sunlight temp plummets to -173 degrees C.

Lunar Surface

Different from the Earth in that there is no erosion.

Highlands - light in color, mountainous, and heavily covered with craters

Maria - dark, smooth plains, which onb average are 3 km lower in elevation than the highlands

Lunar Surface

Impact craters All craters on the Moon are impact cratersFormed when objects from space crashed

into the lunar surface.

Lunar Surface

Ejecta - the materials blasted out during these impacts fell back to the surface.

Rilles - which are meandering, valleylike structures as illustrated in Figure 28-8D on page 754.

Why does the Moon have many craters, while Earth has few?

Composition

The moon is made up of minerals similar to those of Earth - mostly silicates.

History of the Moon

Radiometric dating of lunar rocks from the highlands indicates an age between 3.8 and 4.6 billion years

Regolith - layer of loose rocks on the surface of the moon.

Tectonics on the Moon?

Mountain ranges around maria were not formed tectonically, as mountain ranges on Earth

The crust varies in thickness and is thickest on the far side.

The upper mantle if solid

The moon is not tectonically active

Formation Theories

Capture Theory - The large object floated to close to the Earth’s gravitational pull and became trapped.

Simultaneous formation theory - Moon and Earth formed in the same general.

The impact theory - computer models indicate that the Moon formed as the result of a gigantic collision between Earth and a Mars-sized object about 4.5 billion years ago.

Earth Science

“The Sun-Earth-Moon Relationship”

Sun-Earth-Moon

Relationship between the three are important for many reasons:Sun provides light and warmthSun provides most of the energyMoon raises tidesMoon illuminates sky with monthly cycle of

phases

Daily Motions

The Sun, Moon, planets, and stars do not orbit around Earth everyday. It only appears that way to us because we observe the sky from a planet that rotates once everyday, or 15 degrees per hour.

Earth’s Rotation

2 ways to demonstrate Earth’s rotation:Foucault pendulum - long wire and a heavy

weight. As the Earth turns the pendulum knocks down pegs in the floor.

Coriolis effect - diversion of the flowing air and water are diverted from north-south direction to an east-west direction.

Finish…