Chapter 23 Earth Science

Light travels 300,000 km/s. Many communications satellites are in geosynchronous orbit at about 36,000 km above the earth's surface. If you talk to your friend on the other side of the world via a geosynchronous satellite using Skype or your phone, what is the minimum time delay there will be between you and your friend in your conversation?

.42 seconds

The amount of energy released during a nuclear reaction was established by ________.

Albert Einstein

What does Einstein's formula e = mc2 have to do with the Sun?

It relates to how much energy is carried away from the Sun when mass is ejected from the Sun at the speed c.

You take a block of granite and heat it to 1000 degrees Kelvin, and it glows bright red. If you then heat it to 1200 Kelvin, how might it look different?

It would be brighter and more white.

A microwave oven is a good example of a familiar device that relies on absorption of electromagnetic waves at fixed frequencies by specific elements or compounds. In this case, water absorbs strongly in the microwave band used by the device, heating water molecules in food. What might a microwave oven imply about measuring microwaves emitted by the Sun on Earth?

Microwave radiation will be heavily absorbed in the earth's atmosphere, particular if humidity is high.

What is the ideal way, if cost is no object, for a telescope to avoid atmospheric disturbance?

Place it in space

If a yellow star is moving away from us very rapidly, what color will it appear to be?

Reddish orange

The problems encountered with lenses caused this scientist to build reflecting telescopes of his own design.

Sir Isaac Newton

The study of spectroscopy was begun by ________.

Sir Isaac Newton

Light is an electromagnetic wave, meaning an electric field and magnetic field travel together, oscillating at specific frequency. All metals are electrical conductors and all metals are also opaque to light. Why might this be, knowing the nature of light waves?

The electric field of the wave excites electrons, which move through the solid conductor and dissipate the electric field, stopping the light wave.

If solar flares pose a danger to orbiting spacecraft and astronauts, how much warning is there for the danger?

The primary danger is from high energy particles that travel at the speed of the solar wind 500km/s, so there is ample warning of 3-5 days.

There are websites that predict solar weather, or essentially the impact of the solar wind on earth (in one sense, our planet is within the outer atmosphere of the sun). How is this possible when the speed of light is a fixed quantity?

The solar wind does not travel at the speed of light, so it arrives much later than when a solar event is observed.

Hale discovered that sunspots were associated with magnetic fields. What happens to these magnetic fields during a full sunspot cycle?

They change polarity.

Which of the following is not an advantage that radio telescopes have over optical telescopes?

They have better resolution.

A solar telescope would quickly incinerate your eyes, so how do astronomers save their eyes when looking at the Sun?

They project the telescope image onto a large screen or record the image with a camera.

How do modern telescopes prevent problems of earlier telescopes that limited mirror size and stability during temperature changes?

They use a mirror that is constantly adjusted in shape to adjust for changes in atmospheric distortions.

The old fashioned incandescent light bulb produces yellowish colored light by heating tungsten to a very high temperature and the tungsten radiates light peaking in the yellowish-white range. If you wanted a more blue light that was brighter, what would you need to do with a simple filament light bulb?

You would have to add more electrical current to raise the filament to a higher temperature, which would make it burn out faster.

Classic Newtonian reflector telescopes use a mirror shaped like ________.

a parabola

In a radio telescope, the electromagnetic energy is gathered by ________.

a parabolic metallic mirror, commonly wire mesh

The Spitzer space telescope is ________.

a thermal infrared detecting telescope

The frequency of sunspots and related solar activity is ________.

an 11 year cycle

Hydrogen "burning" in stars is ________.

an atomic reaction that fuses 4 protons to make a helium nucleus, releasing energy by converting mass to energy

Visible light is a small part of the electromagnetic spectrum, but when we see colors, we are seeing ________.

an even narrow range of wavelengths than white light within the visible light spectrum

X-rays have shorter wavelength than visible light; therefore, X-rays ________.

are higher energy than light waves

If you live at high latitude, when do you expect to see the aurora?

at times of high sunspot activity, during the active sun

Because lenses act like a prism to separate the colors of the spectrum, they produce a troublesome effect known as ________.

chromatic aberration

The layer of the solar atmosphere directly above the photosphere is referred to as the ______.

chromosphere

The type of spectrum produced by a common light bulb is a ________.

continuous spectrum

The outermost layer of the Sun is called the ________.

corona

The first telescopes, and most amateur telescopes, rely on the human eye to observe objects. Modern telescopes record the observations with ________.

digital cameras

Which of the following is not a discovery made by the Hubble Space Telescope?

distinction of the various rings of Saturn

The spectra of most stars are dark-line spectra because ________.

elements in the Sun's outer atmosphere absorb in these dark-line bands, blocking the radiation in those bands

Which of the following is not considered a form of electromagnetic radiation?

gravity

To improve the resolution of radio telescopes, astronomers ________.

group smaller telescopes in arrays, like the very large array in New Mexico

What fuel is the source of energy from the Sun?

hydrogen

The Sun produces energy by converting ________.

hydrogen nuclei to helium nuclei

Irregularities in brightness on the Sun's photosphere (granules) are produced by ________.

large convective cells within the photosphere

The source of the Sun's energy is ________.

nuclear fusion

The first telescopes, and most amateur telescopes, rely on the human eye to observe objects. The first improvement on this observation method used ________.

photographic film

Electromagnetic radiation that behaves like a particle is called a(n) ________.

photon

The layer of the Sun that radiates most of the light that reaches Earth is called the ________.

photosphere

During periods of high solar activity, huge cloudlike structures that appear as great arches extending from the Sun are often produced. These solar features are called ________.

prominences

Which of the following colors has the longest wavelength?

red

Nearly all large optical telescopes built today are ________.

reflectors

The most conspicuous features on the surface of the Sun are dark areas called ________.

sunspots

The most explosive events to occur on the Sun are ________.

sunspots

To determine whether a celestial body is approaching or receding from Earth, astronomers employ ________.

the Doppler principle

The part of the Sun clearly visible during a solar eclipse is ________.

the chromospheres

The solar wind originates from ________.

the corona

The wavelength of light emitted from a distance object is related to ________.

the energy of the source—more energetic source has lower wavelength emissions

Streams of protons and electrons emitted from the Sun produce ________.

the solar wind

When excited electrons decay to ground state, hydrogen emits along distinctive line near the visible red. An astronomer observes what appear to be hydrogen emission lines from a distant star but they are in the infrared spectral band. She concludes ________.

the star must be moving very fast away from Earth

As the temperature of a radiating surface is increased ________.

the total amount of energy emitted increases and a larger portion of the energy is radiated at shorter wavelengths (A and C)

Prominences and solar flares present dangers to astronauts primarily because ________.

they can overheat the spacecraft.

Why would astronomers place an X-ray observatory in space, like the Chandra observatory?

to map deep X-ray emissions from deep space, particularly as a proxy for materials being sucked into black holes

Why would astronomers be interested in placing a gamma ray detecting observatory in space?

to map high-energy electromagnetic waves from distant sources that would be blocked out or scattered by Earth's atmosphere