Exploring the Solar System: Telescopes, Planets, and Moons, Exams of Nursing

Download Exploring the Solar System: Telescopes, Planets, and Moons and more Exams Nursing in PDF only on Docsity!

Test bank of Astro 7n Exam 1 (Unit 1 & 2)

questions and answers 2024 /202 5

Newton's First Law - ANSWER- An object at rest, or in motion in a straight line at a constant speed, will remain in that state unless acted upon by a force Ex) If the Sun suddenly disappeared, the Earth would continue in the direction that it was traveling in its orbit at that time Newton's Second Law - ANSWER- The acceleration of a body due to a force will be in the same direction as the force, with a magnitude directly proportional to its mass

• Force = Mass * Acceleration
• (A smaller mass will move faster, if the same force is applied to it.) Newton's Third Law - ANSWER- For every action, there is an equal and opposite reaction
• The Sun exerts force on planets, and they orbit it -- the planets exert equal force on Sun, but it only moves slightly because of its very large mass relative to the planets

The strength of gravity, g, on the surface of a planet is given by: - ANSWER- g=M/R^ where M is the mass of the planet and R is its radius What does more mass mean? - ANSWER- - More gravity If the mass of a planet were twice that of another, but they had the same radius, the gravity felt on the surface of the more-massive one would be twice as strong What does larger separation mean? - ANSWER- - Less gravity If the radius of a planet were twice that of another, the gravity is 1/(2)^2 = 1/ as strong Figure out the surface gravity of Mars, relative to the Earth Mars has 1/10 the mass of the Earth and 1/2 the radius of Earth. So for Mars, - ANSWER- g= (1/10)/(1/2)^2 = (1/10)/(1/4) = 4/

• Mars has a surface gravity 4/10 that of Earth Newton's Universal Law of Gravitation - ANSWER- This law gives the force of gravity between any two objects in the Universe. The force of gravity is proportional to (Mass of object 1) * (Mass of object 2) divided by the distance between the two objects squared:

F ∝ M1 x M2 / d^ If the objects were moved 2 times closer (or, to half of their initial distance between) ... - ANSWER- F ∝ M1 x M2 / (1/2)^2 = M1 x M2 / (1/4) = 4 (M1 x M2) so the gravitational attraction would because 4 times as great What causes day and night? - ANSWER- Rotation of the Earth on its axis How does the Sun appear to move in the sky in the course of a day? - ANSWER- East to West, because of Earth's rotation. The stars and planets move in the same way from our point of view, also, because of Earth's rotation What happens to the Earth in one year? - ANSWER- It orbits the Sun, once Why do we have seasons? - ANSWER- The tilt of the Earth's axis of rotation, with respect to the plane of its orbit around the Sun (The tilt is about 23 degrees) How is the Earth's axis tilted when we have summer in the Northern hemisphere? - ANSWER- With the North pole toward the Sun

What season is it in the Southern hemisphere when it is summer in the Northern hemisphere? - ANSWER- Winter When does Winter begin and what does that mean? - ANSWER- On or about December 21 = in the Northern hemisphere, the nights are longer than days When does Spring begin and what does that mean? - ANSWER- On or about March 21 = days and nights have equal length When does Summer begin and what does that mean? - ANSWER- On or about June 21 = days longer than nights in the North When does Fall begin and what does that mean? - ANSWER- On or about September 21 = days and nights have equal length What happens if the Earth's axis were not tilted? - ANSWER- Seasons would not happen What happens to the moon in 1 month? - ANSWER- It moves once around the Earth

What causes the phases of the moon? - ANSWER- The Sun is lighting up different fractions of the part of the Moon we see from Earth What is the order of the phases of the Moon? - ANSWER- New - Waxing Crescent - First Quarter - Waxing Gibbous - Full - Waning Gibbous - Third Quarter - Waning Crescent - New When is the full moon visible? - ANSWER- Only at night. It transits at midnight, rises 6 hours earlier (at sunset) and sets 6 hours later (at sunrise) When is the new moon visible? - ANSWER- The new moon is visible during the day. It transits at noon; it rises 6 hours earlier (at sunrise), and sets 6 hours later (at sunset) How are the Sun, Earth, and Moon positioned when it is new Moon? - ANSWER- In a straight line: Sun - Moon - Earth How are the Sun, Earth, and Moon positioned when it is full Moon? - ANSWER- Sun - Earth - Moon What is a solar eclipse? - ANSWER- The Moon is blocking the Sun's light, or a location on the Earth's surface is passing under the Moon's shadow

How are the Sun, Earth, and Moon positioned when it a solar eclipse? - ANSWER- Sun - Moon - Earth (as in a new Moon) What is a lunar eclipse? - ANSWER- Earth's shadow passes across the Moon How are the Sun, Earth, and Moon positioned when it is a lunar eclipse, and what phase is the Moon in? - ANSWER- Sun - Earth - Moon (As in a full Moon) Why do eclipses not occur every month on Earth? - ANSWER- The Moon orbits the Earth in a slightly different plane than the Earth orbits the Sun What about eclipses of the moons of Mars? - ANSWER- Mars has two small moons, Phobos and Deimos. Relative to Earth's Moon, they are tiny, and closer to their planet and orbiting faster — and closer to the orbital plane of Mars around the Sun. This leads to more frequent eclipses visible from Mars Constellation - ANSWER- Large defined areas of the sky

• Anything visibly within that region is considered "in" that constellation
• There are 88 of them, in all (dividing up the total celestial sphere)

Ecliptic - ANSWER- The apparent path of the Sun over the course of a year, with respect to the distant stars - also refers to the plane in which the Earth orbits the Sun Zodiac constellations - ANSWER- the 12 (or 13) constellations that lie along the ecliptic The Sun is inside a Zodiac constellation at all times - ANSWER- In each one for about a month, each year

• During that time you cannot see that constellation since it is behind the Sun all day and not on the nighttime side of Earth Winter Zodiac constellations - ANSWER- Ones opposite the Sun in the winter Summer Zodiac constellations - ANSWER- Ones opposite the Sun in the summer What does light have properties of? - ANSWER- It has some properties of a wave and others of a particle Photon - ANSWER- A particle of light

Forms of light, from high energy to low energy - ANSWER- - Gamma ray

• X-ray
• Ultraviolet (UV)
• Visible
• Infrared (IR)
• Microwave
• Radio A bluer color - ANSWER- High-energy light = high frequency = low/short wavelength A redder color - ANSWER- Low-energy light = low frequency = high/long wavelength All forms of radiation travel at.... - ANSWER- the speed of light Wavelengths of radio waves - ANSWER- = Meters and centimeters Wavelengths of visible light - ANSWER- = Ten-billionths of a meter (Hundreds of nanometers)

Wavelengths of X-rays - ANSWER- = even smaller (nanometers down to picometers) A prism splits light into different colors by... - ANSWER- Bending different wavelengths by different angles Blackbody spectrum - ANSWER- Higher temperature = more light in total, and a pearl intensity at a shorter wavelength (or at a bluer color) The Sun's surface temperature is about... - ANSWER- 5800 degrees Kelvin Its spectrum peaks in the visible light region (peak around green — a "green star"!). Room temperature is about... - ANSWER- 300 degrees Kelvin A "blackbody" at room temperature peaks in the infrared (IR) region of light What kinds of radiation get through the Earth's atmosphere? - ANSWER- Visible and radio (so, to be able to see other kinds of light with a telescope — e.g., infrared, x-ray — you would need to place that telescope in space) Continuum Spectrum - ANSWER- Light at all wavelengths

Absorption Spectrum - ANSWER- Shows absorption lines - dark lines in the spectrum at certain wavelengths, superimposed on a continuum spectrum --produced by a (less-energetic_ gas cloud in front of a light source An absorption lines is produced when... - ANSWER- The electrons in atoms absorb photons and remove light of specific energies from the spectrum Then the electons move from a lower to a higher energy level Emission spectrum - ANSWER- Shows emission lines - bright lines at specific wavelengths, in an otherwise empty (dark) spectrum, due to emission of photons from atoms in gas that have electrons in elevated levels (i.e., an "excited" gas) An emission line is produced when... - ANSWER- Electrons jump from higher to lower energy levels, and emit photons of those specific energies Different chemical elements have... - ANSWER- Different energy levels that their electrons can occupy, and thus give rise to different placements and patterns of lines in their spectra; in other words, each chemical element has its own spectral fingerprint

Reflecting telescopes - ANSWER- Use a mirror to collect and focus light Refracting telescopes - ANSWER- Use a lens to collect and focus light What are important qualities of telescopes? - ANSWER- Light gathering power, angular resolution, and the quality of the instruments

• (The magnification is not so important) Light-gathering power - ANSWER- Telescopes collect light in proportion to the area or their mirrors
• The area of circle is proportional to its diameter squared
• Ex) A 2m-diameter telescope collects 2 * 2 = 4
• Or, a 2m-diameter telescope collects the same amount of light as a 1m- diameter telescope in 1/4 the time Angular resolution - ANSWER- The ability to distinguish or separate two nearby light sources (with good angular resolution) Earth's atmosphere limits angular resolution, or "seeing," for ground-based telescopes... - ANSWER- Makes stars twinkle

Magnification - ANSWER- Zooms in on a smaller portion of the sky, to see more detail (but also observes a smaller overall area of the sky) Telescopes above Earth's atmosphere are better because: - ANSWER- - Certain kinds of radiation cannot get through atmosphere all the way to the surface (X- ray, gamma-ray, UV, IR)

• Conditions give clearer images without atmospheric blurring; i.e., better seeing Telescopes above Earth's atmosphere are worse because: - ANSWER- It is hard (and expensive) to get a very large light-collecting area launched into space Distance between Earth and Sun - ANSWER- 1 "Astronomical Unit" 1 (AU) Time for Earth to orbit the Sun - ANSWER- 1 Earth year (365 days) Kepler's First Law - ANSWER- The planets orbit the Sun in elliptical orbits with the Sun at one focus. These ellipses tend to be nearly circular for the planets in our Solar System. Kepler's Second Law - ANSWER- "A line joining a planet and its star sweeps out equal areas during equal intervals of time." Or, a 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) Kepler's Third Law - ANSWER- P^2 = a^3, where P is the orbital period (a planet's year, given as a multiple of Earth years) and a is the semi-major axis (average distance from Sun, given in AU) A hypothetical planet takes 3 years to orbit the Sun. How far from the Sun does it orbit? - ANSWER- P^2 = 3 * 3 = 9 P^2 = a^3 = 9 Well, 2^3 = 8 and 3^3 = 27, so "a" must be something between 2 and 3 A hypothetical planet orbits the Sun at a distance of 5 AU. How long is its orbit period? - ANSWER- a^3 = 5 * 5 * 5 = 125 P^2 = a^3 = 125 Well, 10^2 = 100 , 11^2 = 121, 12^2 = 144, so P must be something between 11 and 12 Mercury - ANSWER- - Can only see close to Sun - and hard to do with the naked eye. Displays phases.

• Much smaller than Earth. 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 every around the planet
• Many craters
• 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, even in daytime
• Density = mass/volume
  • Mercury's average density is 5 grams per cubic centimeter, similar to metals and rocks Venus - ANSWER- - 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)
  • Venus' rotation is in the opposite direction to its orbit around the Sun
  • Combo of these factors leads to a day/night cycle on Venus of about 117 Earth days; also, the Sun travels "west to east" across the sky
• Dense atmosphere - mostly CO
• Surface is very hot because of the presence of large amounts of greenhouse gases
• Density is about 5.2 grams per cubic centimeter

• Active volcanoes, huge lava flows and channels, some large craters, but small meteors burn up in the thick atmosphere Earth - ANSWER- - Fairly thick atmosphere, nitrogen and oxygen molecules; atmosphere cause sky to appear bright during the daytime due to the scattered light from the Sun
• Aurora caused by solar wind particles that hit atmospheric gas and lead to emission of different colors
• Plate tectonics = rocky plates on the surface of Earth float denser but more- fluid rocky material, and move around - leads to continental drift
• Ozone layer protects Earth from solar UV radiation; can be destroyed by certain gases "Greenhouse Effect" - ANSWER- Energy from Sun heats Earth. Earth's surface radiates this heat back towards space by giving off infrared radiation
• Particular gases 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
• Without greenhouse gases Earth's surface would be about 33 degrees Centigrade cooler

Earth's Moon (luna) - ANSWER- - Rotates on its own axis with exactly the same period that it takes to travel once around the Earth

• Lacks as much high-density material such as iron
• 1/4 diameter of Earth
• Has no atmosphere; daytime sky is dark
• Surface gravity is 6 times stronger on the Earth than on the Moon
• Formed later than Earth, from giant impact of a large object with Earth Terra - ANSWER- "land" Light-colored features, heavily-cratered, high peaks; geologically older; highlands uplifted from impacts in early solar system Maria - ANSWER- "seas" Dark-colored, less cratered, valleys; geologically younger; filled by lava 1 to 4 billion years ago Regolith - ANSWER- Powdery dust and rocky debris that covers the Moon; broken apart by small meteorites hitting moon continuously Impact craters - ANSWER- Gouged out from explosions, asteroids or comets that hit the moon

"tidal locking" - ANSWER- The same side of the Moon always faces the Earth Mars - ANSWER- - Mars' days and nights are similar in length to those on Earth

• About half Earth's diameter, 1/10th Earth's mass

• 12 spacecraft have visited Mars; rovers explored surface

• No thick atmosphere, but does have thin one that causes orangish sky; mostly CO2; only modest Greenhouse effect because the atmosphere is so thin
• Average surface temperature is about - 65*C, but can be warmer at its equator
• Iron oxide ("rust") in surface rocks gives Mars its red color
• Has two moons, Phobos and Deimos, but they are tiny - 0nly 0.3% of Mars' size
• Large volcano is 3 times higher than Earth's highest mountain; Martian volcanos appear dormant
• The deepest canyon in Solar System - about 300 times size of the "Grand Canyon" on Earth
• Water once existed on the surface of Mars, but is not flowing regularly there at present; permafrosts = water ice locked beneath Martian soil
• Dust storms are common; occasionally make it hard to see surface features Comets - ANSWER- - A few kilometers in size
• Made of ice and dust - remnants of Solar System formation
• Tails pointing away from the Sun develop due to the solar wind

• Shine by reflected sunlight - i.e., comets do not produce light of their own
• Highly-elliptical orbits that take them far from the Sun; as would be predicted by Kepler's 2nd Law, comets spend most of their time in the outer reaches of the Solar System - they zip by inner Solar System and travel back out very quickly
• Comets move slowly across the sky from our perspective on Earth
• Short-period comets have periods < 200 years
• Long-period comets have longer periods (can be 1,000s of years) and come from the Oort cloud, as much as 50,000 AU from Sun
• Halley's Comet is 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 Asteroids - ANSWER- - Remnants of the Solar System's formation - rocks left over when the planets form
• Many are in the "Asteroid Belt" between Mars and Jupiter
• Asteroid orbits are typically slightly elliptical
• A few major types exist; carbon-rich, metallic, and silicate (stony)
• We see asteroids by reflected sunlight; they do not shine visibly on their own
• The orbits of some asteroids intersect Earth's orbit, and lead to meteors
• Most are less than 1 kilometer in size, but some are bigger
• Like comets, asteroids tend to move very slowly across the sky to a viewer on Earth

Meteors - ANSWER- - Streak across the sky very quickly -- they are also called "shooting/falling stars"

• Most meteors are tiny dust particles or grains -- less than a centimeter in size --
• that rapidly burn up in Earth's atmosphere; pieces of Solar System debris
• Meteors occur when an asteroids crosses Earth's orbit, or when Earth passes through a cloud of debris left behind by a comet passing through the inner Solar System
• A "fireball" = very bright meteor due to larger-than-usual chunk of debris
• A "meteorite" = piece of meteor that survives atmospheric entry, hits Earth's surface
• Asteroid collisions were more common in the younger Solar System
• 65 million years ago a large meteor collision with Earth contributed to the extinction of dinosaurs; dust and smoke thrown into the atmosphere were greater cause of extinction -- not so much the initial impact itself Jupiter - ANSWER- - Jupiter is about 300 times the mass of the Earth, but is on average far less dense -- overall about 1.3 grams per cubic centimeter (about the density of milk); it has a radius of 11 times that of the Earth
• Jupiter has a small ring system
• Jupiter is made mostly of hydrogen and helium gas
  • Gaseous molecules of ammonia, methane, and water vapor also present

• Windspeeds can reach 360 km/he; the "Great Red Spot" is a giant storm larger than Earth -- like an anticyclone on Earth -- and has lasted for at least 300 years
• Jupiter rotates rapidly (once every 10 hours), which stretches the clouds into long bands
• It takes Jupiter 12 Earth years to orbit the Sun
• Interior temperatures and pressures get very high, deep inside Jupiter's gaseous body
• Magnetic fields are 10 times stronger than Earth's due to the rotating liquid- metallic region; interaction between this magnetic field, the solar wind, and Jupiter's atmosphere leads to aurora like we see on Earth
• Methane can convert to carbon soot, and high pressures inside Jupiter can compress that into diamonds Jupiter's moons - ANSWER- - Has more than 50 moons
• The 4 largest were discovered by Galileo in the early 17th century
• Periods range from 1.8 to 17 Earth days, and Jupiter's mass is about 317 Earth masses lo - ANSWER- - One of Jupiter's largest moons
• The closest
• Mostly coppery-yellow with black dots, which are active volcanic sites
• Overall very volcanically active, due to "tidal heating" from Jupiter

• Low crater density
• Yellow color from sulfur Europa - ANSWER- - One of Jupiter's largest moons
• Water-ice surface
• No craters -- ice movement wiped them out
• Liquid water ocean below icy crust Ganymede - ANSWER- - One of Jupiter's largest moons
• Largest moon in the Solar System (larger than Mercury)
• Icy crust
• Has craters so not active now, but cracks show it once was more active Callisto - ANSWER- - One of Jupiter's largest moons
• The farthest out of the four large Galilean moons
• Very heavily cratered -- many young craters
• Does not get heated much
• Has not changed much since its formation
• About the size of the planet Mercury Saturn - ANSWER- - Galileo discovered its rings

• The rings are incredibly thin; made of trillions of individual orbiting objects composed of dusty water-ice crystals
• Mass is about 100 * Earth's (about 1/3 Jupiter); Diameter about 10 * Earth's
• Overall average density is 0.7 grams per cubic centimeter
• The spin axis is tilted about the same as Earth's
• Saturn is mostly made of Hydrogen and Helium; temperatures cooler than on Jupiter
• More than 50 moons by far the largest is Titan (2nd largest moon in Solar System); very think nitrogen-rich atmosphere like the young Earth Uranus - ANSWER- - Third-largest planet, after Jupiter (1st) and Saturday (2nd)
• Orbital period is about 84 Earth years
• Thick atmosphere is made of gas, mostly hydrogen and helium, but some methane too
• Atmosphere doesn't have as continually prominent belts or zones, or bright clouds
• Has liquid, ice core surrounding a smaller rocky core
• Spin axis is nearly in plane of orbit around Sun; leads to continual near- darkness or light for 42 Earth years in a row, at its poles
• Has many thin, faint, dark rings made of carbon Neptune - ANSWER- - Based on the orbit of Uranus not looking quite right

• 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 semi-fluid ices
• Rapid winds and large storms/vortices; include Great Dark Spots, big storms that can come and go over the timescale of a decade
• Ring structure, faint and dark; made of clumps of dust
• 14 known moons
  • Triton (largest): thin atmosphere made of nitrogen and methane; rocky composition; reflective icy surface; ice volcanoes with liquid nitrogen, dust, or methane coming out of them
• Unusual orbit suggests Triton may be a captured Kuiper Belt object Pluto - ANSWER- - 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
• Has 5 moons; largest is Charon, over half diameter of Pluto Pluto not considered a "planet" anymore, because... - ANSWER- 1) 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 Kuiper Belt - ANSWER- Is a disk-shaped region beyond Neptune, ranges 30 - 55 AU Oort Cloud - ANSWER- (houses long-period comets) is out beyond the Kuiper belt In order to be considered a planet, now, an object must: - ANSWER- 1) Orbit the Sun
3. Be massive enough to be nearly round
4. Clear the region around its orbit Formation of the Solar System - ANSWER- 1) Formed 4.5 billion years ago
5. Starting with cloud of gas and dust, it collapses due to its own gravity
6. As it collapses, the spinning cloud flattens and forms a disk
7. The Sun forms at center
8. "lumps" in the disk become planets
9. The regions around these photo-planetary clumps clear out
10. Only rocks and metals survive in inner region; outside, ices and gases also survive

8. Takes a few tens of millions of years to form Terrestrial Planets - ANSWER- - the inner four

• "Earth-like", rocky planets
• Mercury, Venus, Earth, & Mars Jovian Planets - ANSWER- - the outer four
• "Jupiter-like", gas giant planets
• Jupiter, Saturn, Uranus, & Neptune General size of Terrestrial Planets - ANSWER- Earth-sized, or smaller Length of day of Terrestrial Planets - ANSWER- Long day; slow rotation Length of year of Terrestrial Planets - ANSWER- Short Distance from the Sun of Terrestrial Planets - ANSWER- Close Distance from each other of Terrestrial Planets - ANSWER- Pretty close Density of Terrestrial Planets - ANSWER- High