The basics (Lecture 1) Flashcards
What is an Astronomical Unit (AU)
8 light minutes: The distance between the Sun and the earth
How far away is Jupiter in AU?
5 AU
How far away is Neptune in AU? (Outer solar system)
30 AU
What is the nearest star?
Centauri - 4.37 Light years
TASK: Review diagram
Diagram reviewed
What is the galactic plane?
Plane or cross-section of space where most of the mass of any disk-shaped galaxy lies
What is different about the sky below the equator?
Moon & Constellations appear upside down & inverted left/right
What is the diameter of the milky way
100,000 Light years
What is the diameter of the sun
1,500,000 kilometers/0.5 light seconds
What is 10,000 kilometers equal to?
The distance from the equator to a pole of the earth (1/4 the circumference)
What is the circumference of the earth?
40,000 km
What is the diameter of the earth?
15,000 km
What was the big thing discovered (on accident) in New Jersey?
The cosmic microwave backround (background radiation from the big bang)
What is the age of the universe?
13.77 Billion years
What happens to the light from a star the farther away you get?
Light spreads out over a larger area and brightness dims
What is the equation for the brightness of a star?
1/d^2
How do you find the celestial pole?
How fast is the Earth moving at the equator?
1670 km/hour
What is the “morning star” and “evening star”
Venus
What is Right Hand Rotation
The idea of something rotating or orbiting in the same direction that your fingers curl from your thumb on your right hand
Which Two planets orbit/rotate differently from the rest of the solar system
Uranus and Venus
Where in the Milky Way are we?
2/3 of the way out
What is the closest Galaxy?
Andromeda
What is the name of our group of galaxies?
Virgo Supercluster
What is the length of the Virgo supercluster?
100,000,000 light-years
What is the ecliptic (path)
The path of the sun and all the stars in the sky (tilted in relation to the earth because of earth’s axis tilt)
Where are the zodiac constellations?
In the ecliptic path (create a “year’s” worth of constellations correlating to the 12 months)
Where is the Orion omission nebula
Why does the Orion omission nebula have such stark lines?
Because it is a hot glowing hydrogen cloud
What is the red balmer line
Why is Betelgeuse red?
Because it is very cold (red giant)
TASK: review diagram of stars and such
What is Sirius?
The Brightest star in the sky
What is the tilt of the Earth’s axis?
23 degrees
How do you tell whether a phase is waxing or waning?
Right to left; right is bigger left is getting smaller.
What causes earth’s seasons
Axis tilt & rotation around the sun
What is happening during an equinox
The axis points in the direction of the sun
Explain angular size
Small piece of a pie, something is smaller farther away
Define Longitude, Latitude, Prime meridian, and Equator
Longitude - Vertical lines (vertical position)
Latitude - Horizontal lines (horizontal position)
Equator - medial/longest Latitudinal line
Prime meridian - Longest/medial longitudinal line
PARALLAX
Measuring distance with right triangle trigonometry
How long is the lunar (phase) cycle
29.5 days (LUNAR MONTH)
How long does it take for the moon to orbit the Earth?
27 days
What is a sidereal month?
Month based on the time it takes for the moon to orbit the earth (27 days)
Explain eclipses- What causes them?
The earth and moon lining up wiht relation to the sun
Solar eclipse, moon directly between sun and earth
Lunar eclipse - earth casts a direct shadow on the moon
Why do we not have eclipses every month?
Due to the earth’s tilt on its axis and the moons slanted rotation
Explain Opposition, Conjunction, and inferior/superior conjunction
Opposition - the object is behind the earth
Conjunction/superior conjunction (for inner planets only) - the object is in line on the front side, behind the sun but in front of the earth
Inferior conjunction - object is on front side of earth but between earth and sun (inner planets only)
SEE DIAGRAM
When do planets go into their retrograde loop?
At opposition
Explain retrograde/retrograde loop
The brief period of time when an object/planet that is going at a slower speed to Earth appears to go backwards fin the sky as the earth catches up & passes it. The loop represents the observed faltering position in the sky.
