Space Science Exam 2

Characteristics of Jovian Planets

-primarily composed of hydrogen, helium, and hydrogen compounds -Low average density -extensive ring systems, -numerous orbiting moons

What is the asteroid belt?

A large group of asteroids with orbits located between Mars and Jupiter

What is true of radio telescopes?

They have poorer angular resolution than a refractor of same size

The most important advantage of CCDs over film is that

They record much more light in a given exposure time

What problem does adaptive optics correct?

turbulence in the earth's atmosphere which creates twinkling

Which of the following is/are true when comparing radio telescopes to optical telescopes?

-Radio telescopes can observe objects in daytime -Radio telescopes can observe objects even when it's cloudy

As telescopes become larger and larger, astronomers favor ________.

-Reflecting telescopes, in part because large lenses and mirrors sag under their own weight, and it is easier to support a mirror along its entire back side than it is o support a lens only around its edge

Characteristics of Terrestrial Planets

-Small size -Solid, rocky surface -Located within the inner solar system

Meteoric material dates the formation of the solar system at about_____ billion years.

4.6

What is the primary advantage of techniques of radio interferometry?

An increase in resolving power

Planetary orbits

Are almost circular, with low eccentricities

Which of the following is not icy in composition?

Asteroids

The Spitzer Space Telescope (SST) is stationed far from Earth because

Earth is a heat source and the telescope must be kept very cool

The ingredients of a typical comet's nucleus are most likely ________.

Dust and rocky particles trapped in methane, ammonia, and water ice

A telescope with an 8-inch mirror will collect twice as much light as one with a 4-inch mirror.

False

The design of modern X-ray telescopes depends on

Grazing incidence optics

Which of the following is NOT a property of a terrestrial planet?

High mass

List characteristics of Reflecting Telescopes

Hubble space telescope, world's largest telescope, most commonly used by professional astronomers today

Which of the following regions of the electromagnetic spectrum is useful for studying distant galaxies?

Infrared light, visible light, radio waves, ultraviolet light

The best way to study young stars hidden behind interstellar dust clouds would be to use

Infrared light

When used in a single instrument to greatly enhance its resolution, the four separate mirrors of the VLT act as a(n) _____.

Interferometer

Which planet by itself contains the majority of mass of all the planets?

Jupiter

Which of the following are the jovian planets?

Jupiter, Saturn, Uranus, and Neptune only

Which of the following is NOT a reason to use a reflecting telescope rather than a refractor?

Lenses are harder to focus than mirrors

If we double the diameter of a telescope's mirror, what happens to its light-gathering ability?

Light gathering ability quadruples

Which of the following is true about observations at wavelengths other than optical or radio?

Most observations at wavelengths other than optical or radio need to be conducted by space-based telescopes

Assuming that other planetary systems form in the same way as our solar system formed, where would you expect to find terrestrial planets?

Near the Sun

The Arecibo radio telescope is laid out like which optical telescope design?

Prime focus reflector

What is meant in astronomy by the phrase "adaptive optics"?

Rapid modifications are made to the tilt and location of the elements of a telescope to correct for the effects of atmospheric and instrumental distortion

Chromatic aberration in lenses is a result of which wave property of light?

Refraction

It is diffraction that limits the ________ of a telescope of a given objective diameter.

Resolution

Rank based on mass (highest to lowest)

Sun, Jupiter, Earth, Mars, Mercury, Pluto

What is true about solar system densities?

The denser planets lie closer to the Sun

Which of the following statements about the use of infrared telescopes is true?

The detector and telescope must be cooled to very low temperatures

What property of a telescope influences its resolving power?

The size of the main mirror of the lens

Which of the following is an advantage the Hubble Space Telescope has over ground-based telescopes?

There is no blurring due to the atmosphere

One of the primary advantages of CCDs over photographic plates is the former's high efficiency in detecting light.

True

Optical telescopes are usually used only at night, but radio telescopes can be used day or night.

True

Radio telescopes have poorer angular resolution than optical telescopes because radio waves have a much longer wavelength than optical waves.

True

The Cassegrain reflector needs a primary concave main mirror and a smaller, convex secondary mirror to reflect light back through a hole in the primary.

True

Which planet is approximately halfway between Pluto's orbit and the Sun?

Uranus

List characteristics of Refracting Telescopes

World's largest is 1 meter in diameter, Galileo's telescopes, incoming light passes through glass, very large telescopes become "top heavy"

The jovian planets

all have rings around their equators

The primary purpose of a telescope is to

collect a large amount of light and bring it into focus

If our eyes were sensitive only to X rays, the world would appear __________.

dark because x-ray light doesn't reach Earth's surface

If you want to make a very dim object appear much brighter in an image photographed through a telescope, which of the following factors are important?

diameter of the telescope and the length of the exposure

In astronomy, an interferometer can be used to

improve the angular resolution of radio telescopes

If you had only one telescope and wanted to take both visible-light and ultraviolet pictures of stars, where should you locate your telescope?

in space

The James Webb Space Telescope is designed primarily to observe __________.

infrared light

What is the resolution of a telescope?

its ability to distinguish two adjacent objects close together in the sky

Compared to terrestrial planets, jovian planets are

more massive and lower in average density

Which of the following forms of light can be observed with telescopes at sea level?

visible light, radio waves