Final Exam Flashcards
How many Apollo missions landed on the moon?
- Apollo 11, 12, 14,15, 16, 17
How many Astronauts walked on the moon?
12
Name the Inner planets
Mercury, Venus, Earth
Describe Mercury
- Inner planet, no moon, rocky
- Shows phases like the moon
- 40% larger than the moon
- Crater appearance like the moon but no large maria
Venus
- Inner planet, no moon, rocky
- Shows phases like the moon
- bright object in our sky, it appears during sunset/sunrise.
- Similar in size and mass to earth
- Covered by extremely thick atmosphere, surface cannot be observed directly. Runaway greenhouse effect
Mars
- Outer planet, rocky, two small irregular moons- Phobos and Deimos
- Diameter 53% that of earth
- winds are strong enough to produce dust storms
- mars has been visited by numerous missions- orbiters and landers
- Surface is cratered, has deep canyons, massive volcanoes.
- Phobos & Deimos are probably captured asteroids
Jupiter
- Jovian planet- large diameter, low density, gaseous
- mass is more than 300 times earth’s
- Although clouds are twisted by the winds, the zones and belts are stable, have not changed position since first detected.
- largest feature is the great red spot, has lasted more than 300 years. It is a giant hurricane 3 times larger than the earth. two small spots were detected with Hubble recently.
- Jupiters ring is different from Saturn’s rings. It is made of rocky material, not icy.
- 4 galilean moons- Io, Europa, Ganymede, Calisto. Io is closest, Calisto is farthest
- Jupiter has more than 60 other moons, but mostly are small and have irregular shapes. They resemble the asteroids in the belt.
Saturn
- Jovian planet. it can float on water
- Rings: made up of millions icy particles. Rings may be only 100,000 years old. Could have formed if any icy planetesimal came within Saturn’s Roche Limit.
- Titan is giant ice moon with a thick atmosphere. Larger than mercury. Escape velocity low, but able to hold onto gases due to cold conditions. Atmosphere mostly N2, with methane, ethane and other organic compounds. Pressure great enough and temperature low enough to form methane/ethane oceans
Uranus and Neptune
- Blue color- methane absorbs the red light
2. both planets, Uranus and Neptune have similar sizes- 4 times the size of Earth, and have rings like jupiter
Asteroid Belt
located between mars and jupiter
ceres and vesta are among the large asteroids
Trans-Neptunian Objects
Objects found beyond Neptune’s orbit because it has a large moon
Oort Cloud
cloud of comets believed to lie as far as 100,000 AU
Comets
- small dirty snow balls
- travel around the solar system leaving debris. When approach the sun, they develop a tail.
- solar wind will push the tail away from the sun. Meteor showers on earth are often related to material left by comets in their orbits.
What were galileo’s major discoveries using a telescope? Did they support a heliocentric or geocentric system?
Major discoveries include: Sun has spots Venus has phases Jupiter has 4 moons Moon has craters
Supported heliocentric, because the fact that we were in the middle meant we were special
What is the difference between a lunar and solar eclipse
Lunar: Sun - Earth - Moon
Solar: Sun - Moon - Earth
Why do seasons occur?
Because earths axis is tilted 23.5 degrees. Because of that angle the sun shines on different hemispheres
Why do we need a leap year every four years
Because it takes 365.25 days to go around the sun
Why aren’t constellations used very often by astronomers.
Stars aren’t actually physically connected, just a projection. Astronomers only use it to map the sky. Astrology thinks that it’s something that will have a huge impact on people’s lives
What is Copernicus major contribution to astronomy
Copernicus discovered heliocentric- sun in the middle
What are the two most abundant chemical elements in the sun? How old is the sun?
Hydrogen and Helium . 4.5 billion years
What are the sunspots and where are they located? Are they related to the solar activity?
Located in photosphere
What is the main difference between fusion and fission? Which one can we produce on earth ?
Fission is breaking apart (uranium)
Fusion is putting together
Very massive stars and less massive stars lifespan
Very massive = millions
Less massive = billions
What will happen after supernova explosion
Supernova stars can become neutron or black holes. Most massive will become black holes
Rotating stars are known as?
Neutrons. Made of degenerate gas of neutrons Very compact Strong magnetic field Spin very fast Radiate like lighthouse
Evolutionary path of sun
Main sequence
Red giant
Planetary nebula
White dwarf
Sun will not explode as supernova
Since no electromagnetic radiation can escape from black hole how can we detect such things?
Using x Ray satellites we can detect radiation leaving the disk around the black hole
How did Edwin Hubble prove that spiral nebulae were actually galaxies external to the Milky Way
observing types of stars that had change in their brightness called cepheids. Started observing some of the stars in fuzzy nebulae and realized that they were different because the objects were too far away and light takes time to get here.
What were hubbles main types of galaxies
Ellipticals, Spirals, and Irregulars
Milky Way is what type of Galaxy
Spiral
What will happen between our galaxy and andromeda Galaxy 5 billion years from now
Collide. Stars don’t only gas does because of the large separation between stars
Which type of galaxies have old stars
Elliptical
Explain v=HD
V = velocity D= distance H= Hubble constant
Equation tells us further away = faster
How do we know dark matter exists in universe
When astronomers look at a galaxy they can measure how fast stars are moving. When they add up all the matter in the stats and gas visible, it doesn’t add up correctly to what they see. We can see the bright matter like stars but we know some other matter is there because of how it pulls on the bright matter. It is made up of black holes and objects that are too small to be stars, and new particles smaller than atoms
Is the expansion of the universe a direct conclusion from hubbles law
Yes
