ASTRO 100 Unit 2

Mars

"The Red Planet," the color of rust. Has whitish ice caps at its poles, many craters, some prominent old volcanoes, some large valleys, but no significant surface water (lakes, oceans, etc.).

Oort Cloud

(houses long-period comets) is out beyond the Kuiper belt

Miranda

(one of the larger moons) heavily-cratered, with weird valleys and cliffs; appearance caused by upwelling of ices One of Uranus' known moons

Jupiter

- 300 times the mass of the Earth, but is on average far less dense. Radius of 11 times that of the Earth -about the density of milk (about 1.3 grams per cubic centimeter) - made mostly of hydrogen and helium gas. - Windspeeds can reach 360 km/hr - rotates rapidly (once every 10 hours), which stretches the clouds into long bands -It takes 12 Earth years to orbit the Sun -Interior temperatures and pressures get very high, deep inside its gaseous body -likely to have a rocky/metallic core - Magnetic fields are 10 times stronger than Earth due to the rotating liquid-metallic region - Life forms were proposed to exist by astronomers Carl Sagan and Edwin Salpeter; these speculative creatures were referred to as "sinkers," "floaters," and "hunters." - has more than 50 moons -periods range from 1.8 to 17 Earth days, and Jupiter's mass is about 317 Earth masses.

Mars

- days and nights are similar in length to those on Earth - About half Earth's diameter; 1/10th Earth's mass -No thick atmosphere, but does have thin one that causes orangish sky; mostly carbon dioxide; only modest Greenhouse effect because the atmosphere is so thin. - Average surface temperature - 65 ˚C, but warmer at equator - Has two moons, Phobos and Deimos, but they are tiny — only 0.3 % of the planets' size -Their large volcano is 3 times higher than Earth's highest mountain. -The deepest canyon in solar system is about 300 times the size of the Grand Canyon on Earth -Water once existed on the surface, permafrost - Dust storms are common; occasionally make it hard to see surface features.

Jovian Planets

-"Gas Giants" -much larger than Earth-sized - short day (much less than an Earth day); fast rotation -long length of year (orbital period) -very far from Sun -low density (primarily composed of gaseous or light elements) -very cold temperature -all of them have rings -many moons

terra

-(Latin for "land") -light colored features, heavily cratered, peaks, geologically older, highlands uplifted from impacts in early solar system.

maria

-(Latin for "seas") -dark colored, less cratered, valleys, geologically younger, filled by lava 1 to 4 billion years ago

Comets

-A few kilometers in size -Made of ice (both water ice and "dry ice") and dust— remnants of Solar System formation -Tails pointing away from the Sun develop due to the solar wind -Shine by reflected sunlight — do not produce light of their own -Highly-elliptical orbits that take them far from the Sun -Spend most of their time in the outer reaches of the Solar System — they zip by the inner Solar System and travel back out very quickly -Move slowly across the sky from our perspective on Earth -Period rnage from 200 years to 1,000s of years and come from the Oort cloud, as much as 50,000 AU from Sun

Venus

-Closest planet to Earth; visible in western sky in evenings near the Sun, and in the eastern sky just before sunrise; looks like a very bright star. -Also shows phases, like the Moon -Just slightly smaller than Earth in mass (82%) and in radius (95%). - has a longer rotational period (243 days) than its year (225 Earth days) - rotation is in the opposite direction to its orbit around the Sun — i.e., it rotates clockwise when viewed from above (Earth & most other planets rotate counter-clockwise). -The combination of these factors leads to a day/night cycle of about 117 Earth days. -Dense atmosphere -surface is very hot (> 700 K, hotter than Mercury - Density of planet is about 5.2 grams per cubic centimeter, similar to Mercury, and made of metals/rock -Active volcanoes, huge lava flows and channels, some large craters, but small meteors burn up in atmosphere

Neptune

-Discovered in 1846 -Similar to Uranus, but a deeper blue color; atmosphere of hydrogen, helium, and methane -a solid core the size of earth; surrounded by a mantle of liquid ices -Rapid winds and large storms/vortices; include Great Dark Spots -Ring structure, faint and dark; made of clumps of dust -14 known moons

greenhouse effect

-Energy from Sun heats Earth. Earth's surface radiates this heat back towards space by giving off infrared radiation. - Particular gases (including water vapor and CO2) in the Earth's atmosphere recapture and redirect this heat back towards the surface, preventing it from escaping to space. - This trapped heat is redistributed back on Earth; act like a thermal blanket keeping Earth warm.

Ozone Layer

-Stratosphere, protects Earth from solar UV radiation -can be destroyed by certain gases produced by human activity

Uranus

-Third-largest planet, after Jupiter (1st) and Saturn (2nd). Orbital period is about 84 Earth years. -thick atmosphere is made of gas, mostly hydrogen and helium, but some methane too -atmosphere does not have as continually prominent belts or zones, or bright clouds, like Jupiter -has liquid, icy core surrounding a smaller rocky core -Spin axis is nearly in plane of orbit around Sun (it is kind of "rolling on its side"); probably caused by collision early in its history; leads to continual near-darkness or light for 42 Earth years in a row, at its poles -Many thin, faint, dark rings made of carbon ("soot"). -27 known moons

Aurora

-caused by solar wind particles that hit atmospheric gas and lead to emission of different colors -they are prominent near the north and south poles

Pluto

-discovered in 1930 -dwarf planet in the Kuiper Belt -248 Earth-year period of orbit -orbit more highly-elliptical than any of the 8 planets, and not in the same plane; briefly intersects orbit of Neptune -icy ball of rock -very small compared to the planets; Earth's Moon is 7 times as massive - 5 moons

Earth

-fairly thick atmosphere; atmosphere causes sky to appear bright during the daytime; this is the scattered light from the Sun — otherwise the sky would appear dark -aurora -plate tectonics -ozone layer

Moon

-lacks high-density material such as iron, no large iron core -1/4 diameter of Earth -No atmosphere, daytime sky is dark. -Formed later than Earth, front giant impact of a large object (Mars-sized) with Earth.

Mercury

-much smaller than Earth. -It is similar to Mars in mass and radius, and only a bit bigger than Earth's Moon; surface gravity less than on Earth -Temperature is extremely high on the day side and extremely low on the night side, due to lack of an atmosphere to distribute heat evenly around the planet -Many craters, like the Moon, including a few permanently-shadowed craters near the poles that are cold enough all the time as to hold persistent ice deposits; shadows in other craters may be cold, even on the hot/daytime side - Rotates very slowly — 59 Earth days to rotate; has a short year — 88 Earth days to orbit the Sun - has no significant atmosphere; the sky appears black (can see in to deep space), even in daytime — except for the exact position of the Sun - average density is 5 grams per cubic centimeter, similar to metals and rocks

Asteroids

-remnants of the Solar System's formation — rocks left over when the planets form -many are in the "Asteroid Belt" between Mars and Jupiter -Orbits are typically slightly elliptical -a few major types exist: carbon-rich, metallic, and silicate -Visible by reflected sunlight; they do not shine on their own -the orbits of some intersect Earth's orbit, and lead to meteors -most are less than 1 kilometer in size, but some are bigger -like comets, they tend to move very slowly across the sky to a viewer on Earth

Saturn

-rings are incredibly thin; made of trillions of individual orbiting objects composed of dusty water-ice crystals, of various sizes - mass is about 100 x Earth's (about 1/3 Jupiter) -diameter about 10 x Earth's. -overall average density is 0.7 grams per cubic centimeter, which is less than that of water -the spin axis is tilted about the same as Earth's -like Jupiter, made of Hydrogen and Helium; clouds arranged into belts and zones; temperatures cooler than Jupiter. -More than 50 moons

Terrestrial Planets

-rocky, "Earth-like" planets -Earth-sized, or smaller -long day (often much longer than an Earth day); slow rotation - short year (due to being close to Sun -pretty close distance from each other -variable, but generally warmer for being closer to the Sun -high density (made of rocks & metals) -no rings -few or none moons

Meteors

-streak across the sky very quickly -they are also called "shooting / falling stars" (they can travel up to a hundred thousand kilometers per hour) -most are tiny dust particles or grains — less than a centimeter in size -rapidly burn up in Earth's atmosphere; pieces of Solar System debris - occur when an asteroid crosses Earth's orbit, or when Earth passes through a cloud of debris left behind by a comet passing through the inner Solar System

K/T event

65 million years ago a large meteor collision with Earth contributed to the extinction of dinosaurs -dust and smoke thrown into the atmosphere caused extinction, not so much the initial impact itself

Second Kepler Law

A line joining a planet and its star sweeps out equal areas during equal intervals of time. The planet's speed is fastest when the planet is closest to the Sun (at a point called perihelion), and slowest when it is farthest away (aphelion).

11.2 years

A planet is in orbit around the Sun. The semimajor axis of the orbit is 5 Astronomical Units (AU). Use P 2 = a 3 to calculate the period of the orbit in years.

Venus

Bright, yellowish, and cloud-covered (no sharp surface features visible). A clue that this is not a gas giant is that it does not have rings, which all gas giants (aka "Jovian planets") in our Solar System have.

Difference between Kuiper Belt and Oort Cloud

Comets from the Oort cloud have longer periods. Comets from the Kuiper belt tend to orbit in the same plane as the planets in the solar system, unlike Oort cloud.

heliocentric; geocentric

Copernicus proposed the _______________ (Sun-centered) model of the Universe, which replaced the _____________ (Earth-centered) model.

Neptune

Dark and deep blue in color. A few visible dark storm and cloud features. A smaller ring system than Uranus, with just a few thin dark rings.

Uranus

Distinctive deep blue-green color. Generally few visible cloud features. A wide ring system, but the individual rings are very dark and thin, with clear gaps between them (compare to Saturn's). Also, it is tipped nearly on its side, compared to other planets.

Jupiter

Distinctive stormy stripes, cloud bands in different colors (red or brown, to white or even blue-ish). Also has the Great Red Spot, an Earth-sized circular storm in its southern hemisphere.

Miranda

Dull and gray like many moons, but with few large craters and instead an oddly-jumbled striped look, as if it had broken up and been sloppily reassembled at some point — kind of a wrinkled look.

luna

Earth's moon, — Grayish and cratered, and with distinctive large dark maria, the remains of old lava flows that covered large patches of its surface.

ammonia, methane, and water vapo

Gaseous molecules of _______, _______, and _______ lead to different colors in Jupiter's stripey, swirling appearance.

6

Gravity is ___ times stronger on Earth than on the moon.

impact of asteroids

How do most craters on moons form?

84

How many Earth years does it take Uranus to orbit the Sun?

5, Charon is the largest

How many moons does Pluto have?

Saturn's mass

If you know the orbital period and the semimajor axis of the orbit of one of Saturn's moons, what could you determine?

1. orbit the Sun 2. be massive enough to be nearly round 3. clear the region around its orbit.

In order to be a planet, the object must

Adding mass increases gravity and compresses gasses

Jupiter is about three times as massive as Saturn, but only slightly larger. Why?

Saturn

Large ring system. Central planet tan-colored and has long-stretched cloud bands, but less color contrast between them as on Jupiter.

larger

Large-mass planets that are compact have _______ gravity.

Diamond Rain

Methane can convert to carbon soot, and high pressures inside Jupiter can compress that into diamonds

Saturn

Of these choices, which planet has the most moons? Earth Mercury Saturn Mars Venus

lo

One of Jupiter's moons, "I've seen better looking pizzas!" Sulfur volcanoes lend to its yellow color with black specks.

Callisto

One of Jupiter's moons, Generally darker and more cratered than the other Galilean (largest) moons of Jupiter. The largest crater is surrounded by what resemble frozen water ripples (icy body melted from large impact, then re-froze).

Europa

One of Jupiter's moons, Pale tan/white and covered in fine cracks. Very smooth-looking compared to the more cratered moons.

Ganymede

One of Jupiter's moons, an odd marbled look, alternating dark and light areas, and some bright white spots highlighting recent cratering events.

Third Kepler Law

P^ 2 = a^3, where P is the orbital period (in Earth years) and a is the semimajor axis (average Earth distance to Sun) in AU

Charon

Pluto's largest moon Over half the diameter of Pluto

Titan

Saturn's moon, Saturated orange color (as opposed to Venus' pale yellow). Complete cloud cover; cannot see sharp surface features. Like with Venus, the lack of rings is a hint to help not mistake this for a gas giant.

Tidal locking

The Moon rotates on its own axis with exactly the same period that it takes to travel once around the Earth; same side of Moon always faces Earth

the same cloud of gas and dust in which the Sun formed

The planets in our Solar System are thought to have come from

First Kepler Law

The planets orbit the Sun in elliptical orbits with the Sun at one focus. Ellipses are nearly circular in our Solar System.

Venus is more massive and is able to retain a thick atmosphere.

The surface of Venus is hotter than the surface of Mercury because

only near sunrise or sunset.

Venus is visible to us...

volcanic outgassing and sulfuric acid in clouds

Venus' dense atmosphere-mostly carbon dioxide- is produced by ...

Mercury, Venus, Earth, Mars

What are the 4 Terrestrial planets?

Jupiter, Saturn, Uranus, Neptune

What are the four Jovian Planets?

Lo, Europa, Ganymede, Callisto

What are the four largest "Galilean" moons of Jupiter?

atmosphere of hydrogen, helium, and methane

What causes Neptune's blue color?

Methane

What gives Uranus its blue-green color?

Iron Oxide

What in surface rocks gives Mars its red color?

nitrogen and oxygen molecules

What is Earth's atmosphere mostly composed of?

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Kuiper Belt, Pluto, Oort Cloud

What is the order of the planets? Going outward from the Sun ... 1. 2. 3. 4. then the main asteroid belts... 5. 6. 7. 8. then the ____ belt containing dwarf planets like _______. and outside all that, the diffuse ________ with comets and other small icy objects.

1 year (365 days)

What is the time for Earth to orbit the Sun?

Global Warming

When humans produce Greenhouse gases, it leads to extra heating — _____________.

most orbit the Sun in between the orbits of Mars and Jupiter

Which is NOT a characteristic of a comet? A: tails point away from the Sun B: tails become more prominent when comet is close to the Sun C: highly elliptical orbit D: most orbit the Sun in between the orbits of Mars and Jupiter E: they move slowly across the sky

Jupiter's moon Ganymede

Which is largest? Saturn's moon Mimas Mercury Saturn's moon Iapetus Pluto Jupiter's moon Ganymede

Titan

Which of Saturn's moons has a think and nitrogen-rich atmosphere?

the distance from Jupiter to Saturn

Which of the following is the largest distance? A: the distance from Jupiter to Saturn B: the distance from the Sun to the Earth C: the distance from the Earth to the Moon D: the distance from Earth to Mars E: the distance from Mercury to Venus

both the Moon and Mercury

Which of the following objects have a dark/black sky even in the daytime? A: both Venus and Mars B: both Mercury and Mars C: both the Moon and Earth D: both the Moon and Mercury E: both Earth and Titan

The planet Uranus is blue-green and virtually featureless.

Which of the following statements is TRUE? A: Neither Uranus or Neptune have ring systems. B: The planet Uranus is blue-green and virtually featureless. C: There is no evidence to suggest that either Jupiter or Saturn has a liquid metallic or rocky core beneath its gas layers. D: The Great Red Spot is a dust storm near the South polar cap of Mars. E: Jupiter's solid surface lies just below the cloud layers visible from Earth.

Venus

Which of the planets rotates the slowest?

Jupiter

Which planet has a moon with many sulfur volcanoes

Mercury

Which planet has a temperature of 800 degrees Fahrenheit on the side facing the Sun and -290 degrees Fahrenheit on the side opposite the Sun?

Mercury

Which planet looks the most like the Moon?

Galileo

Who discovered Saturns' rings (although he did not know what they were, at the time)

The early solar nebula flattened into a disk.

Why do the orbits of the planets all lie in nearly the same plane?

Prescence of large amounts of greenhouse gases

Why is Venus' surface so hot?

33

Without greenhouse gases Earth's surfaces would be about ____ degreess Centrigade cooler.

Kuiper belt

a disk-shaped region beyond Neptune, ranges 30 - 55 AU

Halley's Comet

a famous short period comet that returns every 76 years — its last visit to the inner Solar System was in 1986; the next return will be in 2061.

The Great Red Spot

a giant storm larger than Earth — like an anticyclone on Earth — and has lasted for at least 300 years

Vesta

an asteroid, — Distinctly non-spherical, unlike the planets. Dull gray and pitted with craters.

Great Dark Spots

big storms that can come and go over the timescale of a decade

1 astronomical unit (au)

distance b/t earth and sun

gravity formula

g ∝ M / R^2

impact craters

gouged out from explosions, asteroids or comets that hit the moon

Mercury

grayish color, and numerous craters. Overall it looks a lot like Earth's moon, but does not have prominent maria, the dark "seas," like the Moon does. (No picture sorry)

Ganymede

largest moon in the Solar System (larger than the planet Mercury); icy crust; has craters so not active now, but cracks show it once was more active

Triton

largest of Neptunes' moons thin atmosphere made of nitrogen and methane rocky composition reflective icy surface; ice volcanoes with liquid nitrogen, dust, or methane coming out of them -may be a captured Kuiper Belt object

Density

mass/ volume =

Reasons why Pluto is not considered a planet

other similar objects were found farther from the Sun — Quaoar, Sedna, Eris 2. not like other outer planets / small; referred to as an "ice dwarf", which are very abundant beyond the orbit of Neptune

Meteorite

piece of meteor that survives atmospheric entry, hits Earth's surface

Regolith

powdery dust and rocky debris that covers the Moon; broken apart by small meteorites hitting moon continuously

plate tectonics

rocky plates on the surface of Earth float on denser but more-fluid rocky material, and move around — leads to continental drift, mountains caused by collisions of plates; plates sliding past each other cause faults

Titan

second largest moon in Solar System; very thick nitrogen-rich atmosphere like the young Earth, but perhaps too cold for life. One of Saturn's moons.

4.5

the Solar System formed _____ billion years ago

lo

the closest moon; mostly coppery-yellow with black dots, which are volcanic plumes; very volcanically active, due to "tidal heating" from Jupiter; low crater density; yellow color from sulfur

Callisto

the farthest out of the four large Galilean moons; very heavily cratered — many young craters; does not get heated much, and has not changed much since its formation; about the size of the planet Mercury

Earth is not the center of the universe

the four largest were discovered by Galileo in the early 17th century CE; they looked like stars, but were found to orbit Jupiter — important because it helped demonstrate that ___________________________________________.

Fireball

very bright meteor due to larger-than-usual chunk of debris

Europa

water-ice surface; no craters — ice movement wiped them out; liquid water ocean below icy crust