Astronomy chapter 1

What makes dark matter and dark energy so mysterious? -Dark matter and dark energy are mysterious because we don't know exactly what they are. -Dark matter and dark energy are mysterious because we don't know how they interact with the ordinary matter of the universe.

-Dark matter and dark energy are mysterious because we don't know exactly what they are.

What makes dark matter and dark energy so important? -Dark matter and dark energy make up the minority of the total energy in the universe. -Dark matter and dark energy make up the majority of the total energy in the universe. -Dark matter and dark energy reduce the total energy in the universe. -Dark matter and dark energy increase the total energy in the universe.

-Dark matter and dark energy make up the majority of the total energy in the universe.

How do the speeds at which we are moving with Earth's rotation and orbit compare to the speeds of more familiar objects? -Earth's rotation carries most people around the axis at about the speed of a commercial jet, and Earth's orbit carries us around the Sun at about the speed of a military jet. -Earth's rotation carries most people around the axis at about the speed at which the Space Shuttle orbits Earth, and Earth's orbit carries us around the Sun at nearly the speed of light. -Earth's rotation carries most people around the axis at about the speed of a car on the freeway, and Earth's orbit carries us around the Sun at about the speed of a commercial jet. -Earth's rotation carries most people around the axis faster than a commercial jet travels, and Earth's orbit carries us around the Sun faster than the Space Shuttle orbits Earth.

-Earth's rotation carries most people around the axis faster than a commercial jet travels, and Earth's orbit carries us around the Sun faster than the Space Shuttle orbits Earth.

Where does dark matter reside in our galaxy -Most dark matter resides in the center of the galaxy. -Most dark matter resides within the disk of galaxy. -Most dark matter resides in the halo of the galaxy.

-Most dark matter resides in the halo of the galaxy.

When we say the universe is expanding, we mean that: -Everything in the universe is growing in size. -The average distance between galaxies is growing with time. -The universe is getting older.

-The average distance between galaxies is growing with time.

The fact that nearly all galaxies are moving away from us, with more distant ones moving faster, helped us to conclude that: -The universe is expanding. -Galaxies repel each other like magnets. -Our galaxy lies near the center of the universe.

-The universe is expanding.

If stars existed but galaxies did not: -We would probably still exist anyway. -We would not exist because life on Earth depends on the light produced by galaxies. -We would not exist because we are made of material that required recycling in galaxies.

-We would not exist because we are made of material that required recycling in galaxies.

The Moon orbits the Sun -once a year. -once a day. -once a month.

-once a year.

How long does it take the Earth to complete one orbit around the Sun? -one week -one month -one day -one year -The time it takes Earth to orbit the Sun changes significantly from one orbit to the next.

-one year

The age of our solar system is about: -one-third of the age of the universe. -three-fourths of the age of the universe. -two billion years less than the age of the universe.

-one-third of the age of the universe.

The total number of stars in the observable universe is roughly equivalent to: -the number of grains of sand on all the beaches on Earth. -the number of grains of sand on Miami Beach. -infinity.

-the number of grains of sand on all the beaches on Earth.

If we represent the solar system on a scale that allows us to walk from the Sun to Pluto in a few minutes, then: -the planets would be the size of basketballs and the nearest stars would be a few miles away. -the planets would all be marble size or smaller and the nearest stars would be thousands of miles away. -the planets would be microscopic and the stars would be light-years away.

-the planets would all be marble size or smaller and the nearest stars would be thousands of miles away.

how long does it take light to travel from moon to earth?

1 second

1 light-hour in kilometers

1.08×10^9 km

1 light-minute in miles

1.1×10^7 mi

1 light-day in miles

1.6×10^10 mi

1 light-minute in kilometers;

1.8×10^7 km

1 light-second in miles;

1.9×10^5 mi

How big is the universe?

100 billion galaxies in the observable universe 14 billion light-years in radius As many stars as grains of sand on Earth's beaches 10^22 stars

how long does light take to travel from andromeda galaxy to earth

2.5 million years

1 light-day in kilometers

2.6×10^10 km

How long does it take our solar system to complete one orbit around the Milky Way Galaxy? -100 million years -1 million years -230 million years -230 thousand years -10 thousand years

230 million years

1 light-second in kilometers

3.0×10^5 km

What is the speed of light?

300,000 km/s or 186,000 miles/s or 3x10^8 m/s

1 light-hour in miles

6.7×10^8 mi

how long does light take to travel from the sun to earth?

8 minutes

how long does it take light to travel from sirius to earth

8 years

what is a star?

A large, glowing ball of gas that generates heat and light through nuclear fusion

what is a planet?

A moderately large object that orbits a star; it shines by reflected light. Planets may be rocky, icy, or gaseous in composition. Each planet must have at least one moon.

what is a comet?

A relatively small and ICY object that orbits a star

What is the ecliptic plane? A) the plane of Earth's orbit around the Sun B) the plane of Earth's equator C) the plane of the Sun's equator D) the plane of the Milky Way Galaxy

A) the plane of Earth's orbit around the Sun

What is a galaxy?

An enormous "island of stars" far out in space, all held together by gravity and orbiting a common center

Dark matter can be detected only by its gravity, that affects other objects we can see. Why can't we see it directly by means of telescopes? -Dark matter is too far away from us to be seen. -Dark matter absorbs light. -Dark matter does not emit light. -Dark matter concentrates in very small space areas.

Dark matter does not emit light.

Which of the following correctly lists our "cosmic address" from small to large? -Earth, solar system, Milky Way Galaxy, Local Group, Local Supercluster, universe; -Earth, solar system, Local Group, Local Supercluster, Milky Way Galaxy, universe; -Earth, Milky Way Galaxy, solar system, Local Group, Local Supercluster, universe.

Earth, solar system, Milky Way Galaxy, Local Group, Local Supercluster, universe;

An astronomical unit (AU) is: 1. any large astronomical distance 2. any planet's average distance from the sun 3. Earths average distance from the sun 4. None of the above

Earths average distance from the sun (150 million KM)

Because nearly all galaxies are moving away from us, we must be located at the center of the universe. TRUE OR FALSE???

FALSE

True or False, The observable universe is the same size today as it was a few billion years ago.

FALSE!!!

Could we see a galaxy that is 50 billion light-years away? -No, because it would be beyond the bounds of our observable universe. -Yes, if we had a big enough telescope. -No, because a galaxy could not possibly be that far away. -None of the above.

No, because it would be beyond the bounds of our observable universe.

why is this statement false? "Because nearly all galaxies are moving away from us, we must be located at the center of the universe."

The fact that nearly all the galaxies are moving away from us made us realize that the universe is expanding, not that we are the center.

explain why the observable universe isnt the same size today as it was a few billion years ago

The observable universe is not the same size today as it was a few billion years ago because it is constantly expanding, and therefore larger today than it was a few billion years ago.

What is an asteroid?

a relatively small and ROCKY object that orbits a star

what is a moon?

an object that orbits a planet

what is a Nebula?

cloud of dust and gas between planets

time formula

distance/speed

speed formula

distance/time

How does Earth move in space?

earth rotates on its axis west to east -person at north pole rotates slower than person at equator -earth rotates at 1000 mph -earth revolves at 67,000 mph

How far is a light year?

nearly 10 trillion km or 9.46 x10^15m

Distance Formula

speed x time

A person located on the equator is orbiting the center of the Earth to the East at 1670 km/s. Relative to the center of the Earth, a person on the North Pole is: -moving toward the South at the same velocity. -stationary, except spinning in-place once per day. -not moving at all. -moving at the same velocity to the East, since they are both on the same planet in space.

stationary, except spinning in-place once per day.

What is the universe?

the sum total of all matter and energy

The star Betelgeuse is about 600 light-years away. If it explodes tonight, -we'll know it immediately because it will be brighter than the full Moon in the sky. -we'll know because debris from the explosion will rain down on us from space. -we won't know about it until 600 years from now. -none of the above.

we won't know about it until 600 years from now.