Quiz: Can You Pass The Astronomy Test?

There are very large extinct volcanoes on Mars.

There is a very deep and long canyon that extends across Mars.

There are dried-up riverbeds on Mars.

Mars has polar caps made of "dry ice."

Mars has two small moons.

Mercury

Venus

Earth

Mars

Jupiter

Rocky minerals and water, as on Earth

Hydrogen and helium

Ammonia and methane

Ammonia and water

Nitrogen and methane

Nuclear fusion occurring in the core of the protosun produced energy that heated the nebula.

As the cloud shrank, its gravitational potential energy was converted to thermal energy.

Radiation from other nearby stars that had formed earlier heated the nebula.

The shock wave from a nearby supernova heated the gas.

Collisions among planetesimals generated friction and heat.

The interstellar cloud from which the solar nebula formed was originally somewhat flat.

The force of gravity pulled the material downward into a flat disk.

As the nebula cooled, the gas and dust settled onto a disk.

It flattened as a natural consequence of collisions between particles in the nebula, changing random motions into more orderly ones.

The original solar nebula happened to be disk-shaped by chance.

Any planets that once orbited in the opposite direction or a different plane were ejected from the solar system.

The laws of conservation of energy and conservation of angular momentum ensure that any rotating, collapsing cloud will end up as a spinning disk.

The Sun formed first, and as it grew in size it spread into a disk, rather like the way a ball of dough can be flattened into a pizza by spinning it.

Luck explains it, as we would expect that most other solar systems would not have all their planets orbiting in such a pattern.

0.5 percent

5 percent

50 percent

98 percent

100 percent

0 percent

0.1 percent

2 percent

20 percent

80 percent

Rocks

Metals

Silicon-based minerals

Hydrogen compounds

Molecules such as methane and ammonia

A collapsing nebula of gas

Flattened, spinning disks

Jovian planets

Terrestrial planets

Strong stellar winds

Asteroids

Kuiper belt comets

Oort cloud comets

All of the above

Our theory is not quite correct because it cannot explain these exceptions.

Most of the exceptions are the result of giant impacts or close gravitational encounters.

The exceptions probably represent objects that formed recently, rather than early in the history of the solar system.

The exceptions probably represent objects that were captured by our solar system from interstellar space.

The exceptions exist because, even though our theory is as correct as possible, nature never follows rules precisely.

Ice that condensed in the solar nebula in the region where Earth formed.

Chemical reactions that occurred in Earth's crust after Earth formed.

Chemical reactions that occurred in Earth's core after Earth formed.

Material left behind during the giant impact that formed the Moon.

Comets that impacted Earth.

Several million years.

Several tens of millions of years.

Several hundreds of millions of years.

About a billion years.

To the present time.

The oldest rocks on Earth.

The oldest rocks on the Moon.

The oldest meteorites.

The atmosphere of Mars.

It hasn't been done yet, but the age of the solar system could be obtained from a sample of Io's surface.

By Huygens, following his realization that other stars are Suns.

By Galileo following the invention of the telescope.

At the turn of last century.

About a decade ago.

At the turn of this century.

Ten

A few hundred

A few thousand

Tens of thousands

Millions

Measuring distances to stars

Searching for planets around stars

Measuring the positions of stars on the sky

Measuring the velocities of stars via the Doppler effect

Using metric units for distance (e.g. meters rather than light years)

Doppler

Astrometric

Transit

Gravitational lensing

Combining all the above

Doppler

Astrometric

Transit

gravitational lensing

combining all the above