Unit 4 PSY

Dark-line (absorption) spectra can be used to identify the ________ present in stars.

Elements

The only planet in the solar system whose axis of rotation lies close to its equatorial plane is ________.

Uranus

The Sun is considered a(n) ________ star.

Average

________ disintegrate and burn up as shooting stars; ________ survive an impact event and a trip through Earth's atmosphere.

Meteors; meteorites

The first modern astronomer to propose a Sun-centered universe was ________.

Nicolaus Copernicus

Which of these men formulated the Law of Universal Gravitation?

Sir Isaac Newton

Which observation supports the theory that the planets formed from a disk shaped nebula?

The planets revolve around the Sun in approximately the same plane of the ecliptic.

What did the Mars rover Opportunity discover on Mars that relates to questions about the existence of water on Mars?

The rover found sedimentary rocks that contained minerals that could only have formed by precipitation from water.

How did Eratosthenes estimate the size of Earth?

They measured the angle of the Sun above the horizon at midday in two places with different latitude and used the angle to estimate the circumference of Earth.

The high surface temperatures of ________ have been attributed to the greenhouse effect.

Venus

Relatively small bodies which generally orbit between Mars and Jupiter are called ________.

asteroids

The outermost layer of the Sun is called the ________.

corona

Radio telescopes have an advantage over optical telescopes in that they can be used ________.

during daylight hours

The most popular theory for the origin of the Moon today is ________.

the early Earth and a planet the size of Mars collided, and the ejected material coalesced to form the earth's moon.

The discovery that the universe appears to be expanding led to a widely accepted theory called ________.

Big Bang Theory

The fate of the universe that is currently favored is the Big ________.

Chill

In the Ptolemaic (Greek) model of the universe, ________.

Earth was the center of the universe

________ are found both on Mars and Earth.

Erosional features related to flowing water

What was Hubble's major contribution to Cosmology?

He identified numerous new galaxies outside the Milky Way.

What fuel is the source of energy from the Sun?

Hydrogen

Galaxies are collections of ________.

Interstellar mattee

Why did Galileo's observation that Venus showed phases like the Moon indicate that the geocentric theory of the solar system was not possible?

It demonstrated that Venus could not be in orbit around earth between earth and the sun because it shows "full" and "new" phases that would never occur with geocentric geometry.

Three laws of planetary motion were discovered by ________.

Johannes Kepler

_______ is the largest and most massive planet in the solar system.

Jupiter

Axial precession is sometimes called the precession of equinoxes because it results in a gradual shift, relative to the celestial background, of the position where the Sun crosses the celestial equator at the equinox. Astrology is a mythology based on things like your "sign" which refers to the position of the Sun in the celestial zodiac (the 12 constellations along the ecliptic) on your birthday. This system was established almost two thousand years ago. If this mythology were true (and you believe your horoscope) can you use the dates for your "sign" based on this 2000 year old system?

No, because 2000 years is almost 1/12, or one full sign shift, in the zodiac, so the 2000 year old signs are off by almost one full sign.

Saturn is famous for its rings. Which of the following Jovian planets does not have rings?

None, all of the Jovian planets have rings

This scientist determined the nature of the forces that kept the planets in their orbits.

Sir Isaac Newton

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.

What is the modern explanation for what the ancient Chinese called "guest stars"?

They are Nova or Supernova.

Why do the planets "drift" east relative to the stars and then move west for periods of time?

They are moving in the same rotation sense as the earth around the Sun, but as the earth moves faster (or slower, depending on the planet) the motion appears to be backwards.

How do astronomers believe an irregular galaxy forms?

They are regular galaxies that are distorted by the gravity field of a large nearby galaxy

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.

A statement you will sometimes hear people say is that a day is not 24 hours but is really 23 hr. 56 min. and 4 sec. What does this refer to?

This is sidereal time, not solar time, a solar day is 24 hours

The surface features of ________ are known only through satellite radar mapping.

Venus

Which planet rotates the opposite direction it revolves around the Sun?

Venus

What is a "main sequence star"?

a star that falls in a band in a band on the H-R Diagram with most other stars

The frequency of sunspots and related solar activity is ________.

an 11 year cycle

On a Hertzprung-Russell Diagram, our Sun is classified as ________.

an average star

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

Which color stars have the highest surface temperature?

blue

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

chromosphere

Patterns or configurations of stars named in honor of mythological characters are called ________.

constellations

Pluto is now classified as a ________ in our solar system.

dwarf planet

The largest known galaxies are ________.

elliptical

The red color of emission nebulae comes from the ________.

energy emission of hydrogen

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

gravity

What two elements formed first?

helium and hydrogen

Apparent magnitude is ________.

how bright stars appear to be from Earth

A comet is visible because ________.

it is a small object, but it ejects gas and dust that at is dispersed by the solar wind to form a tail thousands of km long

What is the main factor that determines what will happen to a star after it consumes all of its nuclear fuel?

mass

The ________ explains how our solar system probably formed from a giant cloud of gases and dispersed solid particles.

nebular hypothesis

A total eclipse of the Sun is only possible at ________.

new moon

The source of the Sun's energy is ________.

nuclear fusion

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

photosphere

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

solar wind

The 5000 year old Stonehenge stone circle of Salisbury Plains, England, allows light shafts to come straight between two rocks on ________ in the Northern hemisphere.

summer solstice

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

the Doppler principle

Based on the observed red shifts in the spectral lines of distant galaxies, astronomers conclude that ________.

the universe is expanding

The final stage for a star which is as massive as the Sun is a ________.

white dwarf

The belt of constellations through which all the planets move is called the ________.

zodiac