SNC1D Science Astronomy Exam Practice Grade 9

How far is a light year?

-9.46 x 10^12 km -9.5 trillion km

What are some differences between asteroids and comets?

-Asteroids have circular orbits while comets have elliptical orbits -Asteroids have no tails while comets have 2 tails

What are some similarities between dwarf planets and asteroids?

-Both are located in the asteroid belt and in the Kuiper belt. -Both orbit the Sun. -Both can have moons.

What are the similarities between Venus and Uranus?

-Both experience retrograde rotation -Both are in the Oort Cloud -Both revolve around the Sun in circular orbits

What are some similarities between static and current electricity?

-Both formed by the flow of electrons -Both rely on the laws of electrostatics

What are some similarities between planets and dwarf planets?

-Both orbit the Sun -Both have nearly round shape

What are some similarities between planets and asteroids?

-Both orbit the Sun -Both inside the Oort cloud

What are some similarities between asteroids and comets?

-Both orbit the Sun -Both rocks of various shape and size

What are some differences between dwarf planets and asteroids?

-Dwarf planets have enough mass that their gravity is strong enough to maintain their nearly round shapes (hydrostatic equilibrium) while asteroids do not. -There are effectively millions of asteroids in our solar system while there are only 5 dwarf planets discovered so far.

What are some differences between planets and asteroids?

-Planets are not inside of the asteroid belt (they are around it) while asteroids can be found in the asteroid belt and the Kuiper belt -Planets are larger and have more mass while asteroids are smaller and have less mass

What are some differences between planets and dwarf planets?

-Planets have cleared their orbit of debris while dwarf planets have not -Planets are closer together while dwarf planets are farther apart in belts

What are some differences between static and current electricity?

-Static electricity is studied using mainly electroscopes while current electricity is studied using circuits. -Static electricity is created by rubbing two different objects together while current electricity is created by the flow of electrons through a wire.

How are Venus and the Earth similar?

-They both have iron-nickel cores and rocky crusts. -They both orbit the Sun within the Oort cloud. -They both are terrestrial planets.

How are Venus and Earth different?

-Venus has an atmosphere composed 96% of carbon dioxide while Earth's atmosphere has 78% nitrogen and only 0.03% carbon dioxide. -Venus has retrograde rotation while Earth has a regular rotation.

What are some differences between Venus and Uranus?

-Venus is terrestrial, Uranus is gas giant -Venus has no rings, Uranus has rings -Venus has no natural satellites, Uranus has 27 natural satellites

What is the Sun's diameter?

1,390,000 km

What were 4 asteroids first discovered?

1-Ceres, 2-Pallas, 3-Juno, 4-Vesta

What are 7 ways humans are searching for intelligent life in the universe?

1. Voyager 1 and 2 2. SETI 3. Arecibo Message 4. Drake equation 5. Fermi Paradox 6. Kepler Mission 7. Exoplanets

What does the Cassiopeia constellation resemble?

A W

What is a comet? What is it made of?

A comet is a celestial body that orbits around the sun. It is made up of a nucleus (solid, frozen ice, gas and dust), a gaseous coma (water vapor, CO2, and other gases) and two tails (dust and ionized gases).

Where does a comet's dust and ion tails always point? Why is this?

A comet's tails always point away from the Sun. Gas (ion) tail points straight away from the Sun. Dust tail curves towards orbital path.

What is a constellation?

A constellation is a group of stars that are considered to form imaginary outlines or meaningful patterns on the celestial sphere.

What does the Big Dipper constellation resemble?

A large spoon

What does the Orion constellation resemble?

A man shooting from a bow and arrow or a small triangular spoon.

What is albedo?

A measure of how much light is reflected from a planet's surface (0 = very dark, 1 = very bright).

What is a meteor? What are they made of? What are they sometimes called?

A meteor is a meteoroid that has entered the Earth's atmosphere, usually making a fiery trail as it falls. Usually made of rock and metals. It is sometimes called a shooting star.

What is a protoplanetary disc?

A protoplanetary disk is a rotating circumstellar disk of dense gas and dust surrounding a young newly formed star.

What is a protostar?

A protostar is a very young star that is still gathering mass from its parent molecular cloud. The protostellar phase is the earliest one in the process of stellar evolution.

What are 3 basic components of spiral galaxies like the Milky Way?

A spiral galaxy like the Milky Way has 3 basic components to its visible matter: (1) the disk (containing the spiral arms), (2) the halo, and (3) the nucleus or central bulge.

What does the Cygnus constellation resemble?

A t or a cross

How can a comet become a meteor?

After passing by the sun several times, the comet can melt to the point where there is no water left and the remaining pieces of rock can crash into earth; meteors.

Who and when proposed the theory of relativity? What does it state?

Albert Einstein, a German scientist you may have heard of, proposed his theory of relativity in 1915. Summed up, the theory states that mass can warp both space and time, which allows large masses like stars to bend light.

What might have caused the extinction of dinosaurs?

An asteroid impact with the Earth.

What is an asteroid?

An asteroid is a large rocky object or very small planet (planetoid).

What is an astronomical unit?

An astronomical unit (AU) is defined as the average distance between Earth and the Sun, 8.3 light minutes, or 149,000,000 km.

What is the closest galaxy to us?

Andromeda galaxy, 2,500,000 ly away

What is obliquity?

Angle between a planet's equator and its orbital plane.

What is orbit inclination?

Angle between a planet's orbital plane and the ecliptic.

How do meteors/meteoroids/meteorites get classified?

Any object in space, usually an asteroidal fragment, is called a meteoroid. When the meteoroid enters the Earth's atmosphere, it is now a meteor. Some meteors fully burn up in our atmospheres while some hit the ground, cool down, and are now called meteorites.

Sun's envelope

Area where heat escapes the core.

Sun's core

Area where nuclear reactions occur, T = 15,600,000 K.

How can asteroids become comets? What do their new orbits look like?

Asteroids can become comets if they get knocked out of their orbits. Their new orbits are highly elliptical (oval).

What are the Trojan asteroids?

Asteroids that orbit the Sun on the orbit path of Jupiter.

Who discovered the heliocentric model, when, and what is it?

Astronomers had speculated about heliocentrism (the idea that the Earth revolves around the sun, not the other way around) since ancient times, but in 1543 Copernicus was the first person to actually demonstrate the math behind the idea to prove it was a viable concept.

Why do we say "average" distance between the Earth and the Sun?

Because Earth's orbit around the Sun is not perfectly circular, at times the Earth is slightly further from the Sun than at other times.

Why do we only see one side of the moon?

Because the moon rotates and revolves at the same rate

What is a brown dwarf?

Brown dwarfs are objects too large to be a planet, but too small to be a star. There is so much friction that they remain balls of hot gas, but the gas does not get hot enough to become a star.

3 things about Mercury are...

Closest to the Sun, fastest period of revolution (88 days), looks like Luna

Sunspots

Cold areas on the Sun's surface, T = 4,000 K.

3 things about Uranus are...

Coldest planet, spins on its side, moons named about characters from Shakespearean plays

When are comets visible?

Comets are only visible when they're near the sun in their highly eccentric orbits.

Which of the following has been called a 'dirty snowball'? Meteor, meteorite, asteroid, comet, or meteoroid.

Comets, since they are made of ice and rock.

Solar Wind

Creates ion tails on comets.

What was the Drake equation designed to do?

Designed to calculate the number of intelligent civilizations that exist in our galaxy right now able to communicate with us right now. The answer was about 900.

How does a dwarf planet differ from a planet?

Dwarf planets have not cleared its orbit of debris, while planets have.

What does it mean to have a transient atmosphere?

Dwarf planets have transient atmospheres, meaning that their atmospheres have an inconsistent nature. They will lift off the grounds during certain periods and settle back down afterward.

Who and when discovered that the universe is expanding?

Edwin Hubble gave the astronomy world a one-two punch of knowledge between 1924 and 1929. Not only was he the first to discover other galaxies, but by tracking their movement he learned that they are moving away from us (and the ones farther away are moving faster), which was the first evidence we had to suggest that the universe is expanding.

Who discovered galaxies?

Edwin P. Hubble

What are the most common galaxy shapes? What are galaxies called if they do not fit into these categories?

Elliptical and spiral. Galaxies that are different are called irregular.

Solar flares

Explosions on the Sun's surface that sends high energy through space (neutrino)

What do Fg, G, m1, m2, and r squared mean in the gravity formula?

Fg=force of gravity G=constant m1=mass of object #1 m2=mass of object #2 r squared=distance between m1 and m2

Who and when made Herschel's map? What was it? What was its original name?

From 1780 to 1834, telescope maker William Herschel and his sister Caroline systematically mapped the heavens, charting thousands of stars and nebulae in the process. He also discovered Uranus, and if astronomers had stuck with his proposed name of Georgium Sidus (George's Star) we would have been saved centuries of terrible jokes.

3 things about Neptune are...

Furthest planet, giant dark spot, largest moon is Triton

Who and when discovered the moons of Jupiter? What were they called?

Galileo, arguably the most important scientist ever, used a fancy telescope he half invented and half stole the idea for to discover four moons orbiting Jupiter in 1610. They were the first moons of another planet to be spotted, making them a landmark discovery. They are called Callisto, Ganymede, Europa, and Io.

What is Jupiter's largest moon?

Ganymede

What are gas giants (outer) planets made of?

Gas and ice

What are globular clusters?

Globular clusters are gravitationally bound concentrations of approximately ten thousand to one million stars, spread over a volume of several tens to about 200 light years in diameter.

3 things about Earth are...

Has life, has surface water, 3rd rock from the Sun

What are nebulae?

Huge clouds of hydrogen gas floating in space.

What are the two most abundant elements in a young star?

Hydrogen and helium

Explain Dynamic Equilibrium.

If our universe has a certain density, it will expand to a certain size and remain that size forever.

Explain the Big Crunch.

If our universe is dense, it will expand to a certain size then begin to shrink. It will collapse into ylem once again and be reborn.

Explain the Big Chill.

If our universe is not very dense, it will continue to expand until it freezes solid at -273 degrees Celcius.

What is the Fermi Paradox?

If there are that many out there, why have we not heard from them - we have not heard from them because they are so far away.

Where can Ceres be found?

In between the orbits of Mars and Jupiter can be found the Asteroid Belt. This is the home of Ceres.

Where can millions of comets be found?

In the Oort Cloud

When a star is being born, how does gravity affect the nebula?

It gets smaller, hotter, flatter, and spins faster.

What is a blue supergiant?

It is the star created when a middle/heavyweight and heavyweight stars' cores merge into one Iron core and the star expands.

3 things about Jupiter are...

Largest planet, most moons (69), giant red spot

3 things about Saturn are...

Largest rings, 62 moons, 2nd largest planet

Solar prominence

Loop of hot gases, gas trying to escape the Sun but pulled back down by gravity.

What does the Moon's anatomy include?

Mare- ancient flat pads of lava, terra- highlands with mountains, rille- deep valleys, craters- holes from asteroid impacts, and regolith- fine, sandy soil.

What is eccentricity?

Measure of how circular an orbit is (0 = circle, >0 = oval).

When do meteor showers occur?

Meteor showers occur when our planet's orbit crosses the orbit of a comet where debris from that comet burns up in our atmosphere.

What are asteroids sometimes known as?

Minor planets or planetoids.

Where are most asteroids located? Where do some approach more closely?

Most asteroids orbit the Sun in the asteroid belt between Mars and Jupiter. A few asteroids approach the Sun more closely.

What is Giotto?

Named after an artist that painted Halley's comet long ago, it is a spaceship that was sent into space to visit Halley's Comet.

Explain the life process of a lightweight star.

Once a star is born, it converts the H (hydrogen) in its core into He (helium). When it runs out of He, the nuclear reactions stop, and gravity shrinks the star into a white dwarf. This eventually cools into a black dwarf.

What do 2 hydrogen atoms in the nucleus of a protostar create?

One helium atom and E (light and heat).

What are open clusters?

Open clusters are physically related groups of stars held together by mutual gravitational attraction.

How many planets and dwarf planets are there in our solar system? Name them in order of closest to farthest from the Sun.

Our solar system is composed of 8 planets and 5 dwarf planets. They are, in order of closest to farthest from the Sun; Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto, Haumea, Makemake, and Eris. The planets can be divided into the inner and outer planets.

What are exoplanets?

Planets located outside of our solar system (orbiting another star). Nearly 4,000 discovered so far. Some are similar to us.

Where are Pluto and Eris be found?

Pluto and Eris are located in the Kuiper belt.

What are the closest stars to us?

Proxima Centauri, Alpha Centauri, and Centauri. They are in a binary star system, meaning they go around each other. They are 4.2 ly away

How are a comet's tails formed?

Radiation from the sun pushes dust particles away from the coma, forming a dust tail, while charged particles from the sun convert some of the comet's gases into ions, forming an ion tail.

3 things about Mars are...

Red planet, liquid water under surface, 2 natural satellites (Phobos and Deimos, Fear and Terror)

What are terrestrial (inner) planets made of?

Rock and metal

What is SETI?

Search for Extra Terrestrial Intelligence.

Name some similarities between inner (terrestrial planets).

Small, close together, hottest (closest to Sun), thin atmosphere, rock + metal, no rings, few (if any moons), have cleared their orbit of debris.

Name some similarities between dwarf planets.

Smaller, terrestrial, farther apart (in belts), farthest from the Sun (except for Ceres), coldest, rock + metal, transient atmosphere, no rings, few (if any) satellites, have not cleared their orbit of debris.

What are Voyager I & II?

Spaceships that were sent to take photos of outer planets. They are just over 141 and 116 AU away after traveling for 40 years.

What are star lanes and dust lanes?

Star lane - spiral of stars in Milky Way Dust lane - lane around star lane

What are cosmogonies?

Stories that describe the birth of the universe.

3 things about Venus are...

The 3rd brightest object in the sky, hottest planet, always covered in clouds

What are the 3 fates of the universe? What do they depend upon?

The Big Chill, Dynamic Equilibrium, and The Big Crunch. They depend on the density of the universe.

What is the Oort Cloud? Who was it named after? How far away is it from the Sun?

The Oort cloud, named after the Dutch astronomer Jan Oort, sometimes called the Öpik-Oort cloud, is a theoretical cloud of predominantly icy planetesimals proposed to surround the Sun to as far as somewhere between 50,000 and 200,000 AU.

Why do larger stars live shorter lives?

The more luminous and large a star is, more nuclear reactions take place at its core. Massive stars live shorter lives because even though they have a larger amount of hydrogen for nuclear reactions, their rate of consuming their fuel is much greater.

What is the most accepted theory in cosmology? What evidence is there to support this theory?

The most accepted theory in cosmology is the Big Bang theory elucidated by Edwin P Hubble. There are two pieces of evidence in support of the theory: the Hubble Graph and Cosmic Background Radiation.

What do the leftovers from the birth of the star create?

The rest of the stellar system (planets, etc).

What is cosmology?

The scientific study of the birth of the universe, and its fate.

Explain the life process of a middleweight star.

These live the same life as a light/middleweight star, except that once they are red giants and they are about to die, they under go a helium flash. This converts all the He in the core into C in a split second. This is so violent, that it blows away the stuff around the core creating a ring around the core. This is called a planetary nebula.

Explain the life process of a light/middleweight star.

These live the same life as a lightweight star, except that as they get older, just before they die, they get very large and are called red giants. These occur because before they die they get very hot. The heat trying to escape is greater than the force of gravity so the star expands.

Explain the life process of a heavyweight star.

These live the same life as a middle/heavyweight star, except that the neutron stars formed is so dense that even life cannot escape it. These are called black holes.

Explain the life process of a middle/heavyweight star.

These stars get so hot in their core that you get multiple cores. The core eventually becomes Fe (iron). When this star dies, so much matter comes crashing into the core so quickly, that the star implodes, then explodes. The explosion is called a supernova. The supernova can be complete creating a nebula. The supernova can be incomplete, leaving behind a core that has undergone some nuclear reactions creating a neutron star. Some neutron stars spin and have a magnetic field around them. These are called pulsars.

What is Saturn's largest moon?

Titan

What is Uranus's largest moon?

Titania

What is Neptune's largest moon?

Triton

Sun's corona

Very hot gases surrounding the Sun, T = 1,000,000 K.

Name some similarities between outer (gas giants) planets.

Very large, far apart, far from Sun (colder), gas + ice, very thick atmosphere, rings, many satellites, have cleared their orbit of debris.

Periodicity

When a comet's return trip is predictable.

What is orbit?

an imaginary line that traces the path of an object through the sky.

What is ecliptic?

an imaginary plane traced out by Earth's orbit about the Sun.

What is the period of rotation?

the time it takes a planet to spin once on its axis of rotation - defines the length of the day.

What is the period of revolution?

the time it takes one object to travel around another object - defines the length of the year.