Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Astronomy Quiz 5
Midterm
| Question | Answer |
|---|---|
| The most abundant elements in the universe are hydrogen and helium, but there are also small but significant amounts of heavier elements in stars and planets and in our own bodies. Where did these heavy elements originate? | in nuclear fusion deep in the interiors of stars |
| What process heated the early solar nebula as it slowly condensed toward a central protosun? | release of heat from the kinetic energy in collisions of particles as they fall toward the center of the nebula |
| What is a proplyd? | protoplanetary disk |
| The reason the inner planets are mostly rock and iron and the outer planets are mostly lighter material, such as hydrogen and ices, is that | the inner solar system was warm enough that the lighter material vaporized (or never solidified), leaving rock and iron to form the inner planets. |
| 1 / 1 point What is the process by which the terrestrial planets are believed to have formed? | process of accretion, in which dust particles stick together to form asteroid-like objects and then collide to eventually form the planets |
| Which components of the present solar system have probably remained essentially unchanged since the solar system was formed and can therefore provide valuable clues to the manner of this formation? | comets, asteroids and meteoritic material |
| The ages of lunar rocks brought back to Earth by astronauts and robotic spacecraft have been determined by measuring the | relative concentrations of radioactive elements. |
| The age of the solar system has been measured by radioactive dating. Which of the following objects gives the most precise value for this age? | oldest meteorites |
| Where in the solar system would you find Kuiper Belt objects? | beyond the orbit of Neptune, extending perhaps as far as 500AU from the Sun |
| An object less than 1000 km across, composed of rock and iron and orbiting closer to the Sun than the planet Jupiter, would be called a(n) | asteroid |
| What does the long, flowing tail of a comet tell us about the solid body of the comet? | It is composed of ice |
| The eight major planets of our solar system can be classified on the basis of their properties and orbits in which of the following ways? | They divide naturally into two main groups. |
| What major fact common to the giant planets leads to the conclusion that they are composed mainly of light elements such as hydrogen and helium? | low average density |
| Which of the following groups of planets have average densities close to that of water, that is, about 1000 kg/m3? | large outer planets because of their composition, mainly H and He |
| Suppose a small object is discovered in orbit around the Sun, with a mass of 1 million kg and a volume of 1000 m3. This object is most probably made almost entirely of | ice |
| Our planetary system is believed to have originated in a disk of gas and dust that surrounded the Sun shortly after the Sun formed. Such disks around young stars are | an observational fact, having been observed around other stars in our Galaxy. |
| What method has been used in the successful search for planets around stars other than the Sun? | measurement of the "wobble" of a star, caused by the orbital motion of the planet, detected either by accurate positional measurement of the star or by wavelength shifts in the star's spectrum |
| Do we have any direct evidence that stars can swallow their planets? | Yes. The presence of a rare element in one star's spectrum indicates that stars can swallow their planets. |
| How does the gravitational microlensing technique work for discovering planets around some stars? | Light from a star is focused on the Earth, making it appear brighter, a nearer star passes in front of it as seen from the Earth. If the nearer star has a planet, the planet also focuses the light, causing a short-duration secondary peak in brightness. |
| A gas giant planet has been found in orbit around the star HD 209458. How have astronomers been able to study the atmosphere of this planet? | The planet frequently passes in front of the star as seen from the Earth, and its atmosphere absorbs some of the star's light at wavelengths characteristic of hydrogen and other elements in the planet's atmosphere. |
Created by:
ches8